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Some aspects of the geochemistry of sulphur and iodine in marine humic substances and transition metal… François, Roger 1987

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SOME A S P E C T S OF T H E GEOCHEMISTRY OF SULPHUR A N D IODINE MARINE HUMIC SUBSTANCES  AND TRANSITION M E T A L ENRICHMENT  IN ANOXIC SEDIMENTS by ROGER FRANCOIS M . S c , The University of Southampton A THESIS  SUBMITTED IN PARTIAL F U L F I L M E N T OF  THE REQUIREMENTS FOR T H E DEGREE OF DOCTOR OF PHILOSOPHY  in T H E F A C U L T Y O F G R A D U A T E STUDIES <  IN  The Department of Oceanography  We accept this thesis as conforming to the required standard  T H E U N I V E R S I T Y O F BRITISH C O L U M B I A 3 June  1987  ® Roger Francois, 1987  In  presenting  degree  at  this  the  thesis  in  University of  partial  fulfilment  of  of  department publication  this or of  thesis for by  his  or  that the  her  representatives.  It  this thesis for financial gain shall not  Department The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3  for  an advanced  Library shall make  it  agree that permission for extensive  scholarly purposes may be  permission.  DE-6(3/81)  requirements  British Columbia, I agree  freely available for reference and study. I further copying  the  is  granted  by the  understood  that  be allowed without  head  of  copying  my or  my written  ABSTRACT.  The  evolution  extracted  from  of the sulphur content of  a  near-shore  S p e c i a l a t t e n t i o n was  sediment  core  humic was  substances  investigated.  taken to a v o i d S contamination  of the humic  m a t e r i a l s d u r i n g sample handling and e x t r a c t i o n .  The S/C  increased  which  suggest by  continuously  with  depth  S a d d i t i o n to the humic matrix  reactions  products. supports  between  The  light  organic matter  t h i s view;  however,  the mechanism i n i t i a l l y  of  enrichment  the  boundaries,  such  i t s oxidation  the  sulphidic  zone,  as the i n t e r f a c e of anoxic microniches  has  redox within  or the s u l p h i d i c / s u b o x i c boundary of the  must have been important  m a t e r i a l s was  addition  and I^S or  diagenesis  i n v o l v e d . Since a l a r g e f r a c t i o n  i n f l u e n c e of sulphur enrichment  humic  during e a r l y  strongly  subsequent i s o t o p i c exchange  o c c u r r e d above  the more o x i d i z e d zones, sediment column,  values  i s o t o p i c composition of t h i s organic sulphur  obscured  The  to  ratios  also  on the complexing  investigated,  increases s i g n i f i c a n t l y  s i t e s for S addition.  and  i t was  c a p a c i t y of  shown that S-  the number of s i t e s on which  Cu  i s i r r e v e r s i b l y bound. Iodine  is  hemipelagic  and  conditions.  In  decrease  c h a r a c t e r i s t i c a l l y e n r i c h e d at nearshore such  the  sediments d e p o s i t e d under  sediments,  bulk  I/C  surface  oxygenated  ratios  org with depth to v a l u e s which are c h a r a c t e r i s t i c of  ii  of  usually anoxic  sediments,  reflecting  early diagenesis. iodine the  preferential  r e l e a s e of i o d i n e  during  There i s some debate as t o whether sedimentary  i s a s s o c i a t e d with the i r o n oxyhydroxide phase  organic f r a c t i o n ,  and whether the decrease i n  3  depth  or  with  I/C org  with  i s due to the d i s s o l u t i o n of the i r o n oxyhydroxides or the  decomposition shown  that  nearshore organic  of l a b i l e organic matter.  fraction in  core and,  the  experiments  on  sedimentary  humic  humic  study,  moreover,  that  iodine  humic  with  the  substances  are  enrichment.  uptake and r e l e a s e of i o d i n e  reduce iodate  Laboratory by  and  mechanism  at the sediment/water  matter to produce  burial,  this  whereby interface  iodinated  organic  molecules.  During  excess iodine c o u l d be d i s p l a c e d from the organic n u c l e o p h i l e s such as s u l p h i d e ions or  thiosulphate,  thus p r o v i d i n g a p o s s i b l e e x p l a n a t i o n f o r the decrease i n with  from  i o d i n e s p e c i e s which f u r t h e r r e a c t s with the  organic  ratio  i t is  sample and i n a  i s mainly a s s o c i a t e d  substances a l s o suggest a  an e l e c t r o p h i l i c  by  iodine  surficial  the  materials  matrix  In t h i s  i n a s u r f i c i a l hemipelagic sediment sediment  involved  to  a  depth  observed i n many  nearshore  and  I  /  c o r  g  hemipelagic  sediments. Bulk metal c o n c e n t r a t i o n s were measured i n the sediments Saanich  Inlet  i n an attempt  metal enrichments Pb,  of  to e s t a b l i s h the occurrence of t r a c e  i n the anoxic c e n t r a l b a s i n . Ba, N i , V, Cr, Zn,  Cu, and Mo were found to be e n r i c h e d i n the anoxic ooze over  the p o s s i b l e c o n t r i b u t i o n s from l i t h o g e n o u s sources.  iii  S p a t i a l and  seasonal  v a r i a t i o n s i n the chemical composition of the  particulates indications  collected of  the  with  mode  Biogenic Ba and Cr appeared  interceptor  of  traps  incorporation  of  gave  further  these  metals.  to be a s s o c i a t e d with o p a l i n e s i l i c a ,  although a l t e r n a t i v e e x p l a n a t i o n s are a l s o p o s s i b l e , for  Ba.  Zinc seemed t o be added to the sediment  association  with  planktonic  additional  source  directly  Similarly,  Ni,  V,  materials, l i n k e d to  essentially  while Cu  the  particularly  required  anoxic  occurring  nearshore  environment  at the  sediment-water  studied  here,  interface.  these  metals  to any s i g n i f i c a n t extent with p l a n k t o n i c  p a r t i c u l a r l y Ni and Mo. the l a r g e s t enrichment  Of a l l the elements  analyzed,  i n the anoxic sediments  iv  in an  environment.  and Mo were added to the anoxic sediments  reactions  associated  settling  by  In  the  were  not  materials, Mo showed  of Saanich  Inlet.  TABLE OF CONTENTS  ABSTRACT 1 INTRODUCTION 1.1 A BRIEF REVIEW OF THE SIGNIFICANCE SUBSTANCES IN THE MARINE ENVIRONMENT 1.2 SYNOPSIS OF THE PRESENT STUDY  OF  HUMIC  2 SULPHUR IN THE HUMIC SUBSTANCES OF NEARSHORE MARINE SEDIMENTS 2.1 INTRODUCTION 2.2 EVALUATION OF THE EXTRACTION CONDITIONS OF SEDIMENTARY HUMIC SUBSTANCES NECESSARY TO ESTIMATE THEIR TRUE, IN SITU SULPHUR CONTENT 2.2.1 INTRODUCTION 2.2.2 MATERIALS AND METHODS 2.2.3 RESULTS AND DISCUSSION 2.2.3.1 CONTAMINATION OF THE HUMIC FRACTION EXTRACTED FROM A SULPHIDIC SEDIMENT BY CO-EXTRACTED PYRITE 2.2.3.2 SULPHUR CONTAMINATION OF THE HUMIC FRACTION DURING THE OXIDATION OF ANOXIC SEDIMENTS 2.2.3.3 SULPHUR CONTAMINATION OF HUMIC SUBSTANCES BY REACTIONS WITH VARIOUS SULPHUR SPECIES DURING ALKALINE EXTRACTION 2.2.3.3.1 SULPHUR CONTAMINATION BY SULPHIDES ... 2.2.3.3.1.1 REACTIONS BETWEEN FREE SULPHIDES AND HUMIC SUBSTANCES IN BASIC SOLUTIONS 2.2.3.3.1.2 REACTIONS BETWEEN ACID VOLATILE SULPHIDES AND HUMIC SUBSTANCES IN BASIC SOLUTIONS 2.2.3.3.2 SULPHUR CONTAMINATION BY ELEMENTAL SULPHUR 2.2.3.3.3 REACTIONS BETWEEN POLYSULPHIDES AND HUMIC SUBSTANCES IN BASIC SOLUTIONS .. 2.2.4 CONCLUSIONS 2.3 EVOLUTION OF THE SULPHUR CONTENT OF THE HUMIC FRACTION OF MARINE SEDIMENTS DURING EARLY DIAGENESIS .. 2.3.1 INTRODUCTION 2.3.2 MATERIALS AND METHODS 2.3.2.1 SITE DESCRIPTION AND SAMPLING PROCEDURE ... 2.3.2.2 EXTRACTION AND ANALYTICAL METHODS 2.3.3 RESULTS AND DISCUSSION  V  1 1 15 19 19 23 23 24 25 25 26  30 30 30 34 35 39 45 47 47 48 48 50 55  2.3.4 CONCLUSIONS 2.4 REACTIONS BETWEEN REDUCED SULPHUR SPECIES AND HUMIC SUBSTANCES AT SEAWATER pH, UNDER LABORATORY CONDITIONS 2.4.1 INTRODUCTION 2.4.2 METHODS 2.4.3 RESULTS AND DISCUSSION 2.5 INFLUENCE OF S-ENRICHMENT ON THE COMPLEXING CAPACITY OF HUMIC MATERIALS 2.5.1 INTRODUCTION 2.5.2 METHODS 2.5.3 RESULTS AND DISCUSSION  80 86 86 87 87 89 89 101 103  3 THE INFLUENCE OF HUMIC SUBSTANCES ON THE GEOCHEMISTRY OF IODINE IN NEARSHORE AND HEMIPELAGIC SEDIMENTS 109 3.1 INTRODUCTION 109 3.2 MATERIALS 112 3 . 3 METHODS 112 3.3.1 ANALYTICAL METHODS 112 3.3.2 EXPERIMENTAL METHODS 112 3.3.2.1 PARTITIONING OF IODINE IN SEDIMENTS 112 3.3.2.1.1 OXYHYDROXIDE PHASE 112 3.3.2.1.2 HUMIC MATERIALS 113 3.3.2.2 UPTAKE OF IODINE BY HUMIC SUBSTANCES 113 3.3.2.2.1 PRELIMINARY EXPERIMENT 113 3.3.2.2.2 REACTION BETWEEN HUMIC SUBSTANCES AND IODATE 114 3.3.2.2.3 RELEASE OF IODINE FROM HUMIC SUBSTANCES 115 3.4 RESULTS AND DISCUSSION 115 3.4.1 THE PARTITIONING OF IODINE IN MARINE SEDIMENTS ...115 3.4.1.1 OXYHYDROXIDES 117 3.4.1.2 HUMIC SUBSTANCES 121 3.4.2 ASSOCIATION BETWEEN HUMIC SUBSTANCES AND IODINE DURING EARLY DIAGENESIS 123 3.4.3 EXPERIMENTAL STUDIES OF THE ADSORPTION AND RELEASE OF IODINE BY SEDIMENTARY HUMIC MATERIALS..126 3.4.3.1 UPTAKE OF IODINE BY HUMIC MATERIALS 128 3.4.3.2 INVESTIGATION OF THE MECHANISM OF IODINE UPTAKE BY HUMIC MATERIALS 130 3.4.3.3 RELEASE OF IODINE FROM HUMIC MATERIALS 138 3.5 CONCLUSIONS 141 4 A STUDY OF THE REGULATION OF METAL CONCENTRATION IN SAANICH INLET SEDIMENTS 4.1 INTRODUCTION 4.2 GENERAL FEATURES OF SAANICH INLET AND SAMPLING LOCATIONS 4.2.1 GENERAL DESCRIPTION  vi  145 145 148 148  4.2.2 4.2.3 4.2.4 4.3 BULK 4.3.1 4.3.2  PHYTOPLANKTON 152 GENERAL GEOLOGY OF THE SAANICH REGION 153 SAMPLING 158 COMPOSITION OF SAANICH INLET SEDIMENTS 158 MINERALOGY OF SAANICH INLET SEDIMENTS 162 GEOCHEMISTRY OF SAANICH INLET SEDIMENTS 167 4.3.2.1 ORGANIC MATTER 167 4.3.2.2 CARBONATE 178 4.3.2.3 MAJOR ELEMENTS 178 4.3.2.3.1 ALUMINIUM 178 4.3.2.3.2 SILICON 178 4.3.2.3.3 POTASSIUM 183 4.3.2.3.4 CALCIUM AND SODIUM 183 4.3.2.3.5 IRON AND MAGNESIUM 189 4.3.2.3.6 TITANIUM 198 4.3.2 3.7 CONCLUSIONS 202 4.3.2.4 PHOPHORUS 205 4.3.2.5 SULPHUR 205 4.3.2.6 MINOR ELEMENTS ..209 4.3.2.6.1 RUBIDIUM AND BARIUM 210 4.3.2.6.2 STRONTIUM 219 4.3.2.6.3 NICKEL AND CHROMIUM 223 4.3.2.6.4 VANADIUM AND MANGANESE 232 4.3.2.6.5 ZINC AND LEAD 241 4.3.2.6.6 COPPER 248 4.3.2.6.7 MOLYBDENUM 251 4.3.2.6.8 ZIRCONIUM 253 4.3.2.6.9 CONCLUSIONS 256 4.3.2.7 IODINE AND BROMINE 257 4.4 ELEMENTAL FLUXES IN SAANICH INLET FROM AUGUST 1983 TO SEPTEMBER 1984 261 4.4.1 FLUXES OF ORGANIC MATTER 266 4.4.1.1 STATION SI-9 266 4.4.1.1.1 45 M 266 4.4.1.1.2 110 M 268 4.4.1.1.3 150 M 268 4.4.1.2 STATION SN0.8 270 4.4.1.2.1 50 M 270 4.4.1.2.2 130 M AND 180 M 270 4.4.1.3 DISCUSSION 273 4.4.2 FLUXES OF MAJOR ELEMENTS 282 4.4.2.1 STATION SI-9 284 4.4.2.1 .1 45 M 284 4.4.2.1.2 110 M AND 150 M 291 4.4.2.2 STATION SN0.8 297 4.4.3 FLUXES OF MINOR ELEMENTS 301 4.4.3.1 BARIUM 301 4.4.3.2 ZINC, CHROMIUM, COPPER, VANADIUM, AND NICKEL 310  vii  4.4.3.2.1 ZINC 4.4.3.2.2 CHROMIUM 4.4.3.2.3 COPPER 4.4.3.2.4 VANADIUM 4.4.3.2.5 NICKEL 4.4.3.3 MOLYBDENUM 4.4.3.4 RUBIDIUM 4.4.3.5 ZIRCONIUM 4.4.3.6 MANGANESE 4.4.4 FLUXES OF IODINE 4.5 CONCLUSIONS  310 315 319 322 325 329 332 334 334 337 341  5 CONCLUDING REMARKS  344  6 BIBLIOGRAPHY  348  APPENDIX I : SAMPLE COLLECTION AND INITIAL PREPARATION 1-1 BOTTOM SEDIMENTS AND PORE WATERS I- 2 SETTLING PARTICULATES  SAMPLE 390 390 391  APPENDIX I I : ANALYTICAL METHODS 399 I I - 1 SOLID PHASE 399 II-1.1 ELEMENTAL ANALYSIS BY X-RAY FLUORESCENCE 399 II —1.1.1 SAMPLE PREPARATION 399 II —1.1.1.1 MAJOR ELEMENTS 399 11-1.1.1.2 MINOR ELEMENTS AND SODIUM 401 11-1.1.1.3 IODINE 405 II-1.1.1.4 CHLORINE AND SALT-CORRECTION PROCEDURE 405 11-1 .2 CARBON AND NITROGEN ANALYSIS 409 11-1.2 . 1 TOTAL CARBON AND NITROGEN 410 11-1.2.2 CARBONATE AND ORGANIC CARBON 410 II-1.2.2.1 GRAVIMETRIC DETERMINATION OF THE CARBONATES 410 11-1.2.2.2 ELEMENTAL ANALYZER 411 11-1.2.2.3 COULOMETRY 412 11-1.3 ELEMENTAL SULPHUR ANALYSIS 414 11-2 PORE WATERS 415 II-2.1 SULPHATE ANALYSIS 415 11-2.2 SULPHIDE ANALYSIS 416 11-3 HUMIC EXTRACTS 416 11-3.1 EXTRACTION OF HUMIC MATERIALS ..416 II-3.2 DISSOLVED ORGANIC CARBON IN HUMIC EXTRACTS ...416 II-3.3 POLYSULPHIDE CONCENTRATIONS IN HUMIC EXTRACTS 417 11-3.4 IODINE IN HUMIC EXTRACTS 418 11-4 HUMIC MATERIALS 418 II-4.1 ISOLATION OF HUMIC MATERIALS 418  viii  11-4.2 CARBON AND NITROGEN CONTENT 11-4.3 IODINE CONTENT I I - 4.4 SULPHUR CONTENT 11-4.4.1 TOTAL SULPHUR 11-4.4.2 PYRITIC SULPHUR 11-4.4.3 ORGANIC SULPHUR 11-4.4.4 ESTER SULPHATE 11-4.4.5 C-BONDED SULPHUR APPENDIX I I I : SEDIMENTATION RATE MEASUREMENT 111-1 PRINCIPLES OF THE METHOD II1-2 MEASUREMENT OF Po ACTIVITY SAMPLES I I I - 3 SEDIMENTATION RATE CALCULATIONS I I I - 3.1 STATION SN0.8 I I I - 3.2 STATION SI-9  419 419 419 419 420 421 421 423  IN  SEDIMENT  424 424 424 426 426 427  APPENDIX IV: CHEMICAL DATA 430 IV- 1 CHEMICAL COMPOSITION OF SAANICH INLET SEDIMENTS ...430 IV- 1.1 CHEMICAL COMPOSITION (SALT-CORRECTED) AND DEPTH OF COLLECTION OF FINE-GRAINED SEDIMENT SAMPLES FROM THE CENTRAL BASIN OF SAANICH INLET 431 IV-1.2 CHEMICAL COMPOSITION (SALT-CORRECTED) AND DEPTH OF COLLECTION OF THE SILL AND COWICHAN ESTUARY SEDIMENT SAMPLES 434 IV-1.3 CHEMICAL COMPOSITION (SALT-CORRECTED) AND DEPTH OF COLLECTION OF THE COARSE-GRAINED NEARSHORE SEDIMENT SAMPLES 436 IV-2 CHEMICAL COMPOSITION OF SI-9 AND SN0.8 SEDIMENT CORES 438 IV-2.1 SALT-CORRECTED MAJOR ELEMENT CONCENTRATIONS: SI-9 438 IV-2.2 SALT-CORRECTED MINOR ELEMENT CONCENTRATIONS: SI-9 439 IV-2.3 SALT-CORRECTED MAJOR ELEMENT CONCENTRATIONS: SN0.8 440 IV-2.4 SALT-CORRECTED MINOR ELEMENT CONCENTRATIONS: SN0.8 441 IV-3 FLUXES OF ELEMENTS AT SI-9 AND SN0.8 442  ix  LIST OF FIGURES 1.  Fractionation  of  humic substances  on the b a s i s  of  solubility  6  2.  Sulphur c y c l e  21  3.  I n f r a - r e d s p e c t r a of humic a c i d s .  43  4.  Map  49  5.  Humic e x t r a c t i o n procedure  6. 7.  Bulk sediment a n a l y s i s Distribution of pore concentrations  8.  Concentration p r o f i l e elemental sulphur  9.  S/C  10.  Total sulphur content of humic a c i d s h y d r o l y z e d i n 5N HC1, 5h at 120 C, normalized to C, , ' ' hyd Polysulphides ( ) associated with the humic e x t r a c t s obtained from core A  71  12.  Isotope composition humic a c i d s  74  13.  Possible mechanism of sulphur addition to the organic matrix i n the o x i c , sub-oxic, and s u l p h i d i c zones of nearshore marine sediments  11.  14.  of J e r v i s I n l e t  51 57  water s u l p h i d e and  isotope  and  sulphate  composition  of  r a t i o s of humic a c i d s e x t r a c t e d from core A  59 60 65 70  s s  n  of f r e e s u l p h i d e s and  hydrolyzed  The periodic table of the elements showing distribution of the "class-a", "borderline", " c l a s s - b " metal and m e t a l l o i d ions ( a f t e r Nieboer Richardson, 1 980)  the and and  84  93  15.  Chelate formation between o-hydroxycarboxylic a c i d s , o - d i c a r b o x y l i c a c i d s , and d i v a l e n t metal c a t i o n s  96  16.  Logarithms of the stability c_onstants f° complexes between Ba through Zn and the b i d e n t a t e ligands oxalic acids, glycine, ethylene-diamine, mercaptoacetic acid and mercapto-ethylamine (after S i e g e l and McCormick, 1 970)  100  r  2 +  1 : 1  2  x  17.  18.  Procedure followed in influence of S-enrichment humic substances 2+ Reaction between Cu and under anoxic c o n d i t i o n s  the experiment on the on the Cu retention by • . S-containing  proteins, 108  19.  I/C , Fe/Al, sedimint core HUD  20.  Sediment core HA-2: (a) Iodine, carbon and C /N r a t i o p r o f i l e s (C and N data from Losher, 1985) °b) I/C ratios i n sediments and extracted humic  and Mn p r o f i l e s of the hemipelagic 22 (from Pedersen et a l . , 1986)  subiiSnces  21.  102  116  124  Sediment c o r e HA-2: (a) s o l i d phase. - Mn (ppm) and S (%) p r o f i l e s , (b) pore waters - Mn and H S (umol/1) p r o f i l e s (from Losher, 1985) 7  125  22.  Displacement substances  139  23.  Map  24.  General geology of Southern Vancouver  25.  Sampling l o c a t i o n s  26.  P e r i o d of deployment  27.  Longitudinal transect of Saanich I n l e t p o s i t i o n i n g of the sediment t r a p s  28.  Distribution sediments  of  organic carbon  in  Saanich  Inlet  29.  Distribution sediments  of  the  in  Saanich  Inlet  30.  Relationship between organic carbon content sedimentation r a t e i n Saanich I n l e t sediments  31.  D i s t r i b u t i o n of CaCO^ i n Saanich I n l e t sediments  179  32.  D i s t r i b u t i o n of A l i n Saanich I n l e t  180  33.  R e l a t i o n s h i p between S i / A l and % C  2  of  iodine  from  I-enriched  humic  of Saanich I n l e t  149 Island  154 159  of the sediment t r a p moorings  C/N  xi  ratio  o r g  160  showing the  sediments  and  161 168 171 175  182  34.  Distribution sediments  of  the  K/Al r a t i o i n  Saanich  Inlet  35.  Distribution sediments  of  the Na/Al r a t i o i n  Saanich  Inlet  36.  Distribution sediments  of  the Ca/Al r a t i o i n  Saanich  Inlet  37.  Histogram ratios in  38.  Correlation sediments  between  %Fe and %Mg  39.  Correlation sediments  between  40.  Distribution sediments  41.  Histogram of d i s t r i b u t i o n Saanich I n l e t sediments  42.  Correlation sediments  43.  Distribution sediments  44.  Correlation sediments  45.  Correlation sediments  46.  Distribution  47.  Correlation sediments  between  %S and %C  48.  Correlation sediments  between  K  49.  Distribution sediments  50.  Distribution  of d i s t r i b u t i o n of the Na/Al Saanich I n l e t sediments  of  and  Ca/Al  in  Saanich  Inlet  %Fe and %A1 i n  Saanich  Inlet  the F e / A l r a t i o i n  Saanich  Inlet  between  Fe/Al  and %K i n  ratio  in  Saanich  Inlet  in  Saanich  Inlet  between  % T i and %A1 i n  Saanich  Inlet  between  % T i and %Fe i n  Saanich  Inlet  of  %Fe  of the  the Fe/K r a t i o  of sulphur i n Saanich I n l e t  of  and  the Rb/K  ?  sediments  i n Saanich  Inlet  Rb  in  Saanich  Inlet  ratio  in  Saanich  Inlet  of Ba i n Saanich I n l e t  xii  sediments  184 185 186 187 190 192 193 195 196 197 199 201 207 208 212 213 215  51.  Distribution sediments  of  52.  C o r r e l a t i o n between I n l e t sediments  53.  Correlation sediments  the  Ba/K r a t i o i n  Saanich  Ba/K and S i / A l r a t i o s  between  Sr  and Ca  in  Inlet  i n Saanich  Saanich  216 217  Inlet 220  54.  Distribution  55.  Correlation sediments  56.  Relationship between I n l e t sediments  57.  Distribution  58.  Relationship between I n l e t sediments  59.  Distribution sediments  60.  Distribution  61.  Correlation sediments  62.  Relationship between I n l e t sediments  63.  Distribution  64.  Relationship between I n l e t sediments  65.  Distribution sediments  66.  C o r r e l a t i o n between Mn and V i n nearshore sands  240  67.  Distribution  242  68.  Relationship between I n l e t sediments  69.  Distribution  of Ni i n Saanich I n l e t between  Ni  and Mg  sediments in  Ni/Mg and  %  of Cr i n Saanich I n l e t  of  Cr/Mg and  "excess"  Cr  between  V  and V/Fe  Ni  of  a  ?  c o  i - Saanich  r  a  .?  *  n  in  Inlet  ?.?  in  Inlet Saanich  sediments ?.?  in  Saanich Inlet  sediments in  sediments  230 231  234 235 237  Saanich  ?  227  233  Saanich  and %C  xiii  Saanich  sediments  and %C  of Pb i n Saanich I n l e t  226  229  Saanich  the Mn/Fe r a t i o i n  Zn/Fe  r  sediments  and %C  of Zn i n Saanich I n l e t  Inlet  n  o  in  of Mn i n Saanich I n l e t Mn/Fe  Saanich  c  %  of V i n Saanich I n l e t  224  238 239  Saanich 244 245  70.  Relationship between I n l e t sediments  71.  Distribution  72.  Relationship between I n l e t sediments  Pb/K and %C  of Cu i n Saanich I n l e t  in  Saanich  sediments %C  249  in  Saanich  ?.?  74.  Distribution  of Mo i n Saanich I n l e t  sediments  254  75.  Distribution  of Zr i n Saanich I n l e t  sediments  255  76.  Correlation sediments  between  77.  Distribution sediments  78.  Correlation sediments  79.  F r a s e r and Cowichan R i v e r d i s c h a r g e from August to September 1984  Br and %C  the  between  Cu  ?!;?  I/C r a t i o I and %C  ?.?  in  250  Distribution sediments  of  "excess"  246  73.  80.  of  Cu/Mg and  ?  Saanich  Inlet  in  Saanich  Inlet  in  Saanich  Inlet  in  Saanich  Inlet  252  258 259 260  1983 262  S°/oo and 0 /H S p r o f i l e s i n the water column over the time of sampling of the s e t t l i n g p a r t i c u l a t e s  264  Comparison between the S°/oo and 0 profiles measured i n the water column on June 18 and August 24, 1984  265  82.  Seasonal f l u x e s of o r g a n i c carbon a t SI-9  267  83.  V a r i a t i o n s i n the o r g a n i c carbon f l u x e s with depth a t SI-9  269  84.  Seasonal f l u x e s of o r g a n i c carbon at SN0.8  271  85.  V a r i a t i o n s i n the o r g a n i c carbon f l u x e s with depth a t SN0.8 ,.272  86.  Seasonal f l u x e s of major elements  87.  Seasonal variations p a r t i c u l a t e s (SI-9)  81.  2  2  2  (SI-9, 45 m)  i n the S i / A l r a t i o of  283  settling 285  xiv  88.  Seasonal f l u x e s of o p a l i n e s i l i c a  286  89.  Seasonal variations settling particulates  287  90.  Seasonal v a r i a t i o n s i n the Fe/K r a t i o of p a r t i c u l a t e s (SI-9, 45 m)  91.  XRD scan of sediment (a) i n August  i n the K/Al and Fe/Al r a t i o s of (SI-9, 45 m) settling  289  t r a p samples c o l l e c t e d at SI-9:  1984; (b) i n November 1983  290  92.  Seasonal f l u x e s of major elements  (SI-9, 110 m)  93.  Seasonal f l u x e s of A l (SI-9, 150 m)  293  94. 95.  V a r i a t i o n s i n A l f l u x e s with depth at s t a t i o n SI-9 Seasonal v a r i a t i o n s i n the C / A l r a t i o of s e t t l i n g p a r t i c u l a t e s (SI-9, 110 and 150 m)  294 295  96.  Seasonal variations i n the Fe/K r a t i o of p a r t i c u l a t e s (SI-9, 110 and 150 m)  296  97.  Variations  98.  Correlation between K and Ba i n the s e t t l i n g p a r t i c u l a t e s c o l l e c t e d at SI-9 (at the 3 depths)  304  99.  Seasonal variations p a r t i c u l a t e s at SI-9  305  g  settling  292  i n A l f l u x e s with depth at s t a t i o n SN0.8 ....300  i n the Ba/K r a t i o of  settling  100. V a r i a t i o n s i n the Ba/K and S i / A l r a t i o s of s e t t l i n g p a r t i c u l a t e s at SN0.8  306  101. F l u x e s of b i o g e n i c Ba at SN0.8  307  102. Seasonal variations particulates 103. Seasonal v a r i a t i o n s particulates  i n the Zn/Fe r a t i o of s e t t l i n g ....311  i n the C /Fe r a t i o of ?.?  104. R e l a t i o n s h i p between Zn/Fe and s e t t l i n g p a r t i c u l a t e s 105. Seasonal variations particulates  and %C  312  i n sediments ?  i n the Cr/Fe r a t i o of  xv  settling  314 settling  316  106. R e l a t i o n s h i p between Cr/Fe and %C and s e t t l i n g p a r t i c u l a t e s 107. Seasonal variations p a r t i c u l a t e s at SI-9  in  sediments  7  318  i n the Cu/Fe r a t i o of  settling  108. R e l a t i o n s h i p between Cu/Fe and %C_ in and s e t t l i n g p a r t i c u l a t e s ? 109. Seasonal variations particulates  111. Seasonal variations particulates  ?  114. Seasonal variations particulates 115. Seasonal variations particulates  321 settling  i n sediments and  i n the Ni/Fe r a t i o of s e t t l i n g  112. R e l a t i o n s h i p between Ni/Fe and sediments and s e t t l i n g p a r t i c u l a t e s 113. Seasonal variations particulates  sediments  i n the V/Fe r a t i o of  110. R e l a t i o n s h i p between V/Fe and %C settling particulates  %  *  c o  r  a  ?  118.  n  t  h  i n the Z r / A l r a t i o of  settling  i n the Mn/Fe r a t i o of s e t t l i n g  21 0 Po p r o f i l e s in gravity s t a t i o n SI-9 and SN0.8  xv i  Q r a  ?  cores  327  333 335 336  SN0.8 338  r a t i o of s e t t l i n g  collected  324  328  settling  i n the I / C  323  e  i n the Rb/K r a t i o of  116. Comparison between the Mn f l u x e s measured at (130 m) with and without NaN^ p o i s o n i n g 117. Seasonal variations particulates  320  from  339  429  LIST OF TABLES  1.  Some chemical  c h a r a c t e r i s t i c s of humic substances .  2.  C and S content  3.  Contamination of humic sediment by p y r i t e  of p l a n k t o n i c m a t e r i a l s acids extracted  2 20  from an anoxic 27  4.  S/C r a t i o of humic a c i d s e x t r a c t e d from an anoxic sediment a f t e r d i f f e r e n t i n t e r v a l s of a i r exposure  29  5.  Sulphur contamination by s u l p h i d e s e x t r a c t i o n of humic a c i d s  31  6.  Sulphur enrichment of humic alkaline solutions  7.  I n f l u e n c e of the presence and removal of the A.V.S on the sulphur content of e x t r a c t e d humic a c i d s  36  8.  Sulphur enrichment of humic sulphur i n a l k a l i n e s o l u t i o n s  40  9.  Sulphur enrichment of humic a c i d s by p o l y s u l p h i d e s i n alkaline solutions  10. D i a l y s i s of p o l y s u l p h i d e s  during  a c i d s by sulphide  present  acids  by  alkaline ions i n  elemental  33  42  i n humic extracts...... . 46  1 1 . Bulk sediment a n a l y s i s  56  12. Amount of C and S e x t r a c t e d by NaOH 0.5N from settling p a r t i c u l a t e materials (% 5.14%) c o l l e c t e d from an i n t e r c e p t o r t r a p deployed i n J e r v i s I n l e t ( s t a t i o n JV11.5)  66  13. M i c r o b i a l S/C r a t i o s  67  c  =  o r a  14. C and S content  of humic a c i d s e x t r a c t e d from core A ........ 68  15. C and S content of humic a c i d s e x t r a c t e d a f t e r h y d r o l y s i s i n 5N HC1, 120 C, 5h 16. Sulphur elemental 17.  isotope sulphur  from core A ...  73  composition of f r e e sulphides, , and hydrolyzed humic a c i d s  75  Isotope mass balance  78  xvii  18. Sulphur enrichment of humic a c i d s by v a r i o u s sulphur s p e c i e s a f t e r I8h. of c o n t a c t a t seawater pH (8.2)  88  19. Unidentate materials  90  20. 21.  ligands  likely  be  found  i n humic  Some examples of b i d e n t a t e l i g a n d s p o s s i b l y present in humic m a t e r i a l s ( a f t e r Houghton, 1979) Influence of S enrichment on the Cu acid-washed t e r r e s t r i a l humic m a t e r i a l s  22. Chemical composition 23.  to  retention  of  104  of HUD 22 (bulk s u r f a c e sample) ....118  Influence of r e s o r c i n o l on the e x t r a c t i o n of from HUD 22 by hydroxylamine h y d r o c h l o r i d e  iodine 120  24. E x t r a c t i o n of i o d i n e from HUD 22 by 0. 5N NaOH 25. Uptake of substances  92  iodine  by  26. Uptake of iodine by substances at pH 7.4-8  122  marine  sedimentary  humic  marine  sedimentary  humic  129 131  27. Rf values of r e s o r c i n o l and i t s i o d i n a t e d d e r i v a t i v e s d u r i n g T.L.C. on S i 0 with 80% CHCl /20% CH COOCH CH ...133 2  28.  3  3  2  3  Influence of the presence of r e s o r c i n o l on the i o d i n e uptake by humic substances a t pH 2.5-3  135  29. Displacement of i o d i n e from humic m a t e r i a l s e x t r a c t e d from HUD 22 by OH and HS  140  30. Major element composition (wt %) of the gneisses and granodiorite found i n the Saanich area (from Clapp, 1913)  157  31. Peak intensity kaolinite  1 64  ratios.  Quartz  /  chlorite  and  32. Peak intensity kaolinite  ratios.  Plagioclase / chlorite  and  33. Peak intensity kaolinite  ratios.  Hornblende /  and  34. C/N  organic  ratio  of  materials  xv i i i  chlorite  of  marine  and  165 1 66  terrestrial origin 35. Sediment Inlet  169  accumulation r a t e  (w) and %C  i n Saanich 174  36. Carbon accumulation r a t e s i n the deep basin of Saanich Inlet  176  37. Average Sr/Al ratio i n the different sediment present i n Saanich I n l e t  222  38. Annual carbon and aluminium f l u x e s and r a t e s i n sediment a t s t a t i o n SI-9  types  of  accumulation  274  39. Seasonal carbon and aluminium f l u x e s at s t a t i o n SN0.8 ...279 40. Annual C f l u x e s and accumulation r a t e s i n sediment at s t a t i o n SN0.8 41. Average C /Al and S i / A l r a t i o s i n sediment trap m a t e r i a l s colSected at s t a t i o n SI-9 and SN0.8 from May 5 to August 24, 1 984  281  299  42. F l u x e s of biogenic Ba at s t a t i o n SN0.8 (50 m)  303  43. E v a l u a t i o n of the extent of f l u s h i n g which occurred d u r i n g deployment of the sediment t r a p s  396  44. Instrumental c o n d i t i o n s f o r elemental sediment samples by X-ray f l u o r e s c e n c e  400  45. XRF a n a l y t i c a l p r e c i s i o n 46. XRF analytical sodium  analysis  of  f o r major elements  precision  f o r minor  402  elements  and  404  47. Comparison of the r e s u l t s obtained from the a n a l y s e s of 1 g and 0.5 g sediment p e l l e t s using the same c a l i b r a t i o n curve  406  48. C o r r e c t i o n f o r s e a s a l t  408  49. Comparison analyzer  of  C a n a l y s e s by Leco and C a r l o Erba  50. Sulphur recovery by C r C l / H C l treatment 2  xix  >  CHN  413 422  Acknowledgements. I would l i k e to thank my s u p e r v i s o r , h i s constant guidance Dr.  T.F.  Pedersen  discussions. committee,  I Dr.  am  Dr.  S.E. C a l v e r t , f o r  and encouragement throughout  t h i s work, and  f o r many hours of e n l i g h t e n i n g and also  Andersen,  g r a t e f u l to the other Dr.  Lewis,  and  Dr.  cheerful  members  of  my  Lowe f o r t h e i r  w i l l i n g n e s s to answer q u e s t i o n s and grant v a l u a b l e a d v i c e . Finally,  very s p e c i a l thanks go t o my w i f e ,  d r a f t i n g the 118 f i g u r e s present  for  i n t h i s d i s s e r t a t i o n and f o r her  unwavering support d u r i n g the past two y e a r s .  xx  Michaela,  1.  INTRODUCTION.  1 . 1 A BRIEF REVIEW OF THE SIGNIFICANCE OF HUMIC SUBSTANCES IN THE MARINE  ENVIRONMENT.  "Humic assemblage which  substances" i s a g e n e r a l term used to d e s c r i b e of r e f r a c t o r y ,  constitute  t e r r e s t r i a l , and reactions They  the  s t r u c t u r a l l y complex,  bulk of the organic  marine  environments.  of some r e p e t i t i v e ,  u n i t s , and consequently  identical.  in  result  of  their  significance  their  bulk  structural  distinctive  properties.  Some substances  from  random  f o r environmental  i n order problems,  to  chemical  well established of  polymers  well-  exactly  understand  variations  f e a t u r e s must be c o r r e l a t e d  of .the main are  structurally  one must t h e r e f o r e work i n  t h e i r general s t r u c t u r e and,  p o l y d i s p e r s e d system  with  their  of  humic  characteristics  (Table 1). They c o n s i s t displaying a  in  wide  of  range  a of  (or m i s c e l l a r ) weights extending from a few hundreds t o  s e v e r a l hundred thousands.  Their a c i d i c character  is  mainly to the presence of O - c o n t a i n i n g f u n c t i o n a l i t i e s , carboxyl  aquatic,  no two samples w i l l be  For d e s c r i p t i v e purposes,  terms  molecular  matter  polymers  between b i o g e n i c molecules r e l e a s e d by the b i o s p h e r e .  are not assemblages  defined  They  acidic  that  and  p h e n o l i c h y d r o x y l groups,  1  and the  attributed primarily  occurrence  of  Table 1: Some chemical c h a r a c t e r i s t i c s of humic substances, - Elemental composition C: 0: H: N: S: - Polydisperse  40 32 4 1 .1  58 50 8 8 4  system i.e.  mixture  range  of  organic molecules with  a  wide  of molecular ( m i s c e l l a r ) weights from a few  hundreds to s e v e r a l hundred  thousands.  Acidic A t t r i b u t e d mainly t o t h e i r - C a r b o x y l i c groups: R-C=0 OH N  -Phenolic  groups:  - Other s t r u c t u r a l groups o f t e n r e c o g n i z e d i n humic molecules Amino  -NH„  Unsaturated carbonyl  -CH=CH-CH=0  Amide  R-C=0  Anhydride  Alcohol  R-CH 0H  Imino  Aldehyde  R-C=0  Ether  R-CH ~0-CH -R'  Enol  R-CH=CH-0H  Ester  R-C=0 O-R'  Ketone  R-C=0 R'  Quinone  2  Keto a c i d s R-C=0 COOH  Peptide  2  R-C-O-C-R' IT 0 0 II  =NH 2  o-< R-C=0 H-N-R'  2  quinones  and polyhydroxy  phenols  i s thought  to be,  at l e a s t  in  p a r t , r e s p o n s i b l e f o r t h e i r reducing a b i l i t i e s . A l s o , p r o t e i n and carbohydrate  r e s i d u e s a r e o f t e n found c h e m i c a l l y a t t a c h e d to the  humic m a t r i x . The  s e t of chemical  of humic substances  r e a c t i o n s which leads t o the  ( i . e . the h u m i f i c a t i o n process) and t h e r e f o r e  t h e i r g e n e r a l s t r u c t u r e and composition w i l l , influenced  various  i n broad  by the s e t t i n g of the environment i n which  being formed.  formation  Elemental a n a l y s i s ,  spectroscopic  methods  between humic substances  terms, be they  are  f u n c t i o n a l group a n a l y s i s and show  some  clear  d e r i v e d from d i f f e r e n t  t e r r e s t r i a l vs marine, o x i c vs anoxic, e t c . ) . Some of these d i f f e r e n c e s w i l l  distinctions  environments(e.g.  f o r e s t s o i l vs g r a s s l a n d , be mainly the r e s u l t of the  nature of t h e i r b i o g e n i c p r e c u r s o r s (e.g. t e r r e s t r i a l vs marine), while  in  some other cases the environmental  their  formation  w i l l be the o v e r r i d i n g  conditions  factor  during  (e.g. o x i c  vs  anoxic). Humic compared al.,1985). tend  substances with  of marine o r i g i n are e n r i c h e d i n N  and  t h e i r t e r r e s t r i a l c o u n t e r p a r t s (Vandenbroucke  H et  A l s o , t o t a l a c i d i t y and p a r t i c u l a r l y p h e n o l i c a c i d i t y  to be much lower  i n the-marine  m a t e r i a l s (Vandenbroucke  et  a l . , 1 9 8 5 ) . T h i s i s c o n s i s t e n t with the higher a l i p h a t i c and lower aromatic (Stuermer  character  generally  displayed  by  these  substances  and Payne, 1976; Stuermer et a l . , 1978; Hatcher  1980), which would r e f l e c t  et a l . ,  the l a c k of aromatic p r e c u r s o r s i n the 3  marine  environment  and  the r e l a t i v e  l i p i d s i n t h e i r formation Differences substances  are  (Harvey and less  environmental  character lipids  documented  between  However,  conditions  (i.e.  formed it  tend  with a higher  Kaplan,  that  to  Humic substances formed  have  a  H content) and  1972;  greater  Stuermer et a l . ,  1978).  hand, humic substances formed under o x i c c o n d i t i o n s  more  oxygen,  through  reducing  to be e n r i c h e d  other  possibly  under  seems  (Demaison and Moore, 1980). They a l s o c o n t a i n more  (Nissenbaum and  humic  be d i s t i n g u i s h e d between marine humus  from oxic or anoxic sediments.  anoxic  planktonic  Boran, 1985).  conditions.  s i g n i f i c a n t d i f f e r e n c e s can  under  well  of  o r i g i n a t i n g from the same m a t e r i a l but  different  extracted  importance  o x i d a t i v e cleavage  in  sulphur On  the  contain  during  the  h u m i f i c a t i o n process (Vandenbroucke et a l . , 1 9 8 5 ) . Because of the is  very  structures  reliable  w i l l vary  studying  formation  or the it  variations.  This  Their  simple,  properties  i n s u b t l e ways from sample to  and and,  i n f l u e n c e of environmental parameters on  their  i n f l u e n c e of s t r u c t u r a l c h a r a c t e r i s t i c s on  their  i s o f t e n d i f f i c u l t to d i s t i n g u i s h d i r e c t is  f u r t h e r complicated  i s o l a t i n g them from t h e i r of  parameters.  by  it  sample  the  properties,  properties  in humus formation,  d i f f i c u l t to c h a r a c t e r i z e humic substances  well-defined,  when  random f a c t o r i n v o l v e d  the  by the  inorganic matrices.  isolated  The  product are always  4  causal  difficulty  of  structure  and  more  or  less  modified  by  extraction  the  extraction  many  different  procedures which a l t e r the e x t r a c t e d humic  materials  to v a r y i n g degree are being reliable  procedure.  used,  i t i s very d i f f i c u l t  i n t e r - l a b o r a t o r y comparisons.  divergence of views concerning  Since  Hence,  peats  or  humic  sediments by  extraction  procedure leads  strong  alkaline  are  alkaline being  that  which i s  aqueous s o l u t i o n s ,  precipitated under the  at  pH,  (Fig.  extractable  although other  Bremner and low  from  soils,  to an e m p i r i c a l f r a c t i o n a t i o n  material  used (e.g.  such as  solutions.  based on t h e i r pH-dependent s o l u b i l i t y behaviour acids  Lees,  wide  process.  substances are e x t r a c t e d  fairly  obtain  is a  even fundamental questions  the broad p r i n c i p l e s of the h u m i f i c a t i o n Traditionally,  there  to  This scheme  1). Humic  (generally  by  solvent  systems  are  Hayes,  1985))  and  1949;  while f u l v i c a c i d s remain in  solution  same c o n d i t i o n s . Humin r e f e r s to that p a r t of the humic  m a t e r i a l which i s not e x t r a c t a b l e . Although convenient as a crude fractionation  technique,  this  approach  operationally-defined  fractions  delineations  which  mainly  fractionation  procedures.  conventional c o u l d be actual  artificial.  represent reflect  Moreover,  the since  ways to perform these o p e r a t i o n s ,  found i n any method  substances  is  used.  of these three Also,  it  is  fractions, now  only  The 5  and  there  are  a given  molecule  no  depending on  accepted  solubility  arbitrary  extraction  are a f a m i l y of macromolecules e x h i b i t i n g  s p e c t r a of molecular p r o p e r t i e s .  These  that  the  humic  continuous  characteristics  HUMUS  E x t r a c t with a l k a l i i ( Insoluble )  } ( Soluble )  1  HUMIN  *  Treat  ( Precipitated ) HUMIC A C I D S  Fig.  I with a c i d 1  *  ( Not p r e c i p i t a t e d  )  FULVIC ACIDS  1: F r a c t i o n a t i o n of humic substances on the b a s i s of t h e i r pH-dependent s o l u b i l i t y p r o p e r t i e s .  6  of  these  molecules  are  determined  v a r i e t y of more fundamental polarity,  ionization  different  combinations  result  1,  fulvic weight high  interactions  p r o p e r t i e s , such as molecular  constant of f u n c t i o n a l of  a  weight, Many  properties  could  Therefore,  a c c o r d i n g to the f r a c t i o n a t i o n  of  groups, e t c .  these fundamental  i n i d e n t i c a l s o l u b i l i t y behaviour.  g e n e r i c term, Fig.  by the  the  same  scheme presented i n  c o u l d r e f e r to widely d i f f e r e n t molecules. For i n s t a n c e , a c i d s are g e n e r a l l y c o n s i d e r e d to be of  (e.g.  Hayes and S w i f t ,  molecular weight  lower  molecular  197,8). However, the occurrence of  f u l v i c a c i d i s o c c a s i o n a l l y r e p o r t e d (e.g.  Naik and Poutanen, 1984). C o n s i d e r i n g these two p o i n t s ( i . e . that the  presence  humic and  of a humic molecule  i n any of the three c l a s s e s  substances w i l l be s t r o n g l y dependent upon the f r a c t i o n a t i o n procedure  used,  and  of  extraction  that these c l a s s e s  will  a l s o encompass molecules with widely d i f f e r e n t chemical c h a r a c t e ristics), of  one may  using  specific  molecules. vagueness (e.g.  feel justified  Such  terms  practice  for may,  such  the  ill-defined  in part,  suitability groups  of  be the source of  the  c h a r a c t e r i s t i c of a l l d i s c u s s i o n s of humic  Aiken  appropriate  et a l . , to  1985).  Alternatively,  continuous investigated  spectrum using  of  seem  more  where  humic  f a m i l y of molecules d i s p l a y i n g a  any - given  modern a n a l y t i c a l  r a t h e r than a r b i t r a r i l y  substances  i t may  work w i t h i n a conceptual framework  substances are c o n s i d e r e d as one  1985),  in questioning  property  can  be  (e.g.  Swift,  s u b d i v i d i n g these s p e c t r a  solely  7  techniques  which  on s o l u b i l i t y p r o p e r t i e s . A c c o r d i n g l y , most of the work presented here  w i l l be done on what would be c o n v e n t i o n a l l y c a l l e d a humic  acid  fraction,  However,  because  i t i s the e a s i e s t  environmental  appreciated reservoir of  for  some  instance,  time.  They  are known  1983).  impact on the l e v e l of C 0  it  to  be  has  been  2  major  i s in a  state  As such, i n the  r e p o r t e d that the  during  magnitude  as  d e f o r e s t a t i o n c o u l d be of the  the  (Woodwell et a l . , kerogen,  the  r o c k s . Kerogens,  amount r e l e a s e d due to  each  i n e r t macromolecules  2  substances  same  order  fuel  found i n a l l  of  burning  sedimentary  environment  of e l e c t r o n s b u r i e d mainly as reduced C  to  accumulated  i n the atmosphere or l o c k e d i n  oxidation  C0  1978). A l s o , humic substances are the p r e c u r s o r  corresponds  and  of  along with reduced sulphur, represent one of the  mole  humification  may  atmosphere.  major p o o l s of "reducing e q u i v a l e n t " i n our o x i d i z i n g (i.e.  they  amount  fossil  been  a  to the atmosphere by the o x i d a t i o n of humic  occurring  of  importance of humic substances has  r a p i d turnover ( B o l i n ,  have a s i g n i f i c a n t  released  characterizable.  i n the carbon biogeochemical c y c l e which  relatively  For  isolate.  i s meant to encompass the bulk of  o r g a n i c matter not r e a d i l y s t r u c t u r a l l y The  to  the c o n c l u s i o n s drawn w i l l be a p p l i e d i n a more g e n e r a l  sense t o humic substances which the  fraction  1/4 mole of 0  2  produced  processes i n sediments, state  by  8  photosynthesis oxides).  which  S and  Therefore,  by determining the  of the o r g a n i c carbon  or  was  amount finally  buried,  may  have  steady-state be  had  maintenance  involved at  f u e l formation.  was  1974).  is  effect  determined  determining  the  i n the atmosphere and  may  feedback  s u i t a b l e f o r the  in  mechanism existence  of  ( G a r r e l s and Perry,  accumulated  composition by  the  of the  on the sea f l o o r  humification  of  the  the  processes  g e n e r a t i o n of f o s s i l  content due  of f o s s i l  acid  rain.  incorporated al.,  1977;  will  peat-forming, have  matter  be  partly  will  be  study of the  f o r our  source r o c k s .  understanding in  Also,  predicting the  problems a s s o c i a t e d with the that t h i s  sulphur  at a very e a r l y stage of c o a l formation Casagrande and Ng, 1983;  can  et a l . ,  which  f u e l s and w i l l h e l p  I t has been argued  A l t s c h u l e r et a l . ,  which  f u e l s has been r e c e n t l y a s u b j e c t of  to the environmental  of  et  of petroleum  fossil  as a f u n c t i o n of the environment of  t h e r e f o r e be very important  occurrence  of  (Tissot  c h a r a c t e r i s t i c of the environment of d e p o s i t i o n . The e v o l u t i o n of humic substances  complex  organic  of t h i s organic matter  its  1974).  a l s o of relevance to the study  depends on the composition  formation w i l l  for  The amount and nature of hydrocarbons  first  The  some  g e o l o g i c a l time  Humification  generated  in  levels  organisms through  which  important  amount of oxygen present  directly  be  an  1979;  sulphur concern, formation is  being  (Casagrande  Casagrande et a l . , 1979;  Lowe and B u s t i n , 1985), i . e . d u r i n g the  h u m i f i c a t i o n stage. A study of t h i s phenomenon w i l l  an important  bearing on the development of  the removal of sulphur from  coal. 9  techniques  for  Besides have  these long-term c o n s i d e r a t i o n s , a l l humic substances  common p r o p e r t i e s which confer on them the a b i l i t y  immediate  effects  on the environment  Among these p r o p e r t i e s , t h e i r a b i l i t y behaviour  i n which they  reducing  established (Szilagyi,  properties  (Szilagyi,  of  1973).  1967), V 0 ~ t o V 0  2 +  3  are  have  found.  to complex metals and t h e i r  i n redox r e a c t i o n s are the best  The  to  documented.  humic  substances  are  well  The r e d u c t i o n of Mo0 ~ to  Mo0  4  (Szalay and S z i l a g y i ,  1967; Wilson 3+  and Weber,  1979; Templeton and Chasteen,  (Szilagyi,  1971) and H g  (1983)  facilitate  the  would  electron  could  be  e l e c t r o n acceptors Photo-reduction readily  the  in  a  discrete.  humic redox  They a l s o argue as  system which would allow otherwise u n a v a i l a b l e of  i s responsible euphotic  essential process  that  Mn oxides  by  acids  could  couples  which  that  anaerobic  an e x t r a c e l l u l a r  them t o use t e r m i n a l  to them. humic  substances  occurs  i n s u r f a c e seawater. Sunda et a l . (1983) argued that 2+  reduction in  demonstrated  a c t u a l l y use humic a c i d s  transport  to Fe  A l s o , S c h n i d l e r et a l . (1976) and  e l e c t r o n t r a n s f e r between  otherwise  organisms  have  1980), Fe  2+  to Hg° ( A l b e r t s e t a l . , 1974) by humic  2 +  substances have been r e p o r t e d . Zimmermann  zone  micronutrient  f o r the higher Mn of the oceans.  important  r e a d i l y a v a i l a b l e form 10  concentration  Since  for photosynthetic  may be p a r t i c u l a r l y more  + 2  manganese organisms,  i n maintaining to  this found  i s an such  a  a pool of Mn  phytoplankton.  Also,  a  similar by  mechanism  Miles  and  consumption  involving a ferrous-ferric cycle  Brezonic  found  in  (1981) the  to  explain  photic  zone  the  of  was  proposed  substantial  0  humic-coloured  2  lake  waters. Another ability earth  important  to  interact  and  by n e u t r a l  ion-exchange  interactions. to  the  are  to  of  salt  atoms  electron-donating  systems  coordination some  1969).  of  chelates.  Chelate the  groups  N,  these  It  the P,  likely  be u n i d e n t a t e steric  substances  and v a r i o u s m e t a l s ,  al.,1970),  although  the  natural  environment  has  The most  often  salicylate-type  cited ring  model  not  mainly  organic metal  As,  invokes  attributed  ions  either or  aromatic  structures 1 1  which via  via  TJ -  rings  most  complexes;  etc.)  of  these  however,  will  allow  very often  postulated  observed  such  humic  in  et the  demonstrated.  f o r m a t i o n of and  as to  Gamble  compounds  unambiguously  (Schnitzer  known  between  in the  also  of  the  these  matrix  etc.)  that  1982),  describe  p a r t i c u l a r l y Cu ( e . g .  been  totally  complexes,  often  occurrence never  been  their  alkaline-  Stevenson,  configuration  been  interaction  are  adequately  more s t a b l e m u l t i d e n t a t e  strong  (e.g.  bonds,  seems  f o r m a t i o n has  ions  i n the  S,  is  particularly  therefore  (olefinic  haphazard  formation  explain  Since  bonds w i t h  (O,  compounds w i l l  instances,  ions,  extraction  functional  form c o v a l e n t  Saxby,  humic s u b s t a n c e s  e q u i l i b r i a cannot  electron-donating  (e.g.  of  metal  T h i s p r o p e r t y has  presence  able  with  t r a n s i t i o n metals.  exchangeable simple  property  phthalate  Skinner,  and 1965;  Boyd et  a l . ,  conjugated  1981).  ketonic  and S t e v e n s o n , may a l s o al.,  be  involved  N-containing  content  of  + +  be  ,  on t h e  which  for  1958;  able  Pearson,  to  compete  mainly  1981),  level  monitoring system, processes fully  of  this  is  play  quickly  their  at  much h i g h e r  (Ahrland,  the  Also,  involvement for  their  have a  metals  humic  higher  1966;  S  significant  since C a  and  + +  concentrations,  a S-containing  whose  present  in  a crucial are  an  is  complexing Ahrland  will group  et  of  the  have the  in  transition  various  a l . ,  accurate  to  set  of  natural  12  balance.  Because  of a  environmental  Being a  dynamic  negative  feedback  be u n r a v e l l e d  consequences of  period  mechanisms  nutrients.  necessary.  be a c h i e v e d b y a  and p r e d i c t  first  role  attained,  intricacies  state  the  essential  concentration  can only  understand  the  transition  relatively  important  could  of  found  p r o c e s s e s and t h e r e f o r e  toxic  1972)  for  group  1972).  et  aromaticity  their  1985),  Boyd  1968).  metals,  (Whitfield,  of  (Rashid,  seawater  an O - c o n t a i n i n g  Some  life  origin  in  and  NH g r o u p s  1976;  of  as  (Piccolo  that  a l . ,  degree  a l . ,  such  suggested  et  al.,1978) et  groups,  indicates  may be p a r t i c u l a r l y  complexation  occur  low  et  been  Vinkler  their  Vandenbroucke  groups  marine  much l e s s  than  1972;  (Nissenbaum and K a p l a n ,  influence Mg  some e v i d e n c e  Stuermer  (e.g.  functional  have a l s o  (Rashid,  1960;  N content  materials  and  Considering  (e.g.Breger,  of  O-containing  structures,  1981),  1979).  high  Other  any  in  order  to  modification  Owing  to  their  potential  complexing  metals", such  humic  materials  processes.  buffers  They  (Mantoura,  influence  of  capacity may  with  regard  to  suitable  any e r r a t i c  supply of metals to a  of n a t u r a l organic matter,  mechanism has been suggested  upwelled Ryther,  observed water  given the  biotope.  detoxifying  1978), and a s i m i l a r  t o e x p l a i n the i n c r e a s e i n  upon a d d i t i o n of a zooplankton  rich  metal  p a r t i c u l a r l y with respect to  Cu (e.g. Lewis et al.,1973; Sunda and Lewis,  production  as  i n n u t r i e n t s but low i n  DOC  primary  extract (Barber  complexation  affect  their  of  geochemical  mobility.  It  has  also  been  shown  that humic m a t e r i a l can r e a d i l y l e a c h metals  their  matrices,  mineral  (Kononova et a l . ,  Drever,  1983).  transported  then It  most  terrestial  Once  1973;  leached,  Tan, these  1975; metals  act  as a metal r e s e r v o i r  (Stevenson  and  ecosystems  p o o l of  micronutrients  (Zunino and 13  Martin,  phase, which  Ardakani, constitute  available 1977).  and  either  sediments  has been argued that humic substances may important  be  or adsorbed on a s o l i d  on the humic f r a c t i o n of s o i l s or  Baker,  Antweiller may  from  process  Ponomoreva and Ragim-Zade, 1969;  as s o l u b l e complexes,  particularly  the  1964;  thus enhancing the weathering  Kodama and S c h n i t z e r ,  1972).  and  metals by humic substances w i l l  experimentally  could  to  1969).  The  1973;  in  Saar and Weber, 1982), and so dampen the  V a r i o u s l a b o r a t o r y experiments have demonstrated ability  "nutrient  have played a p r i m o r d i a l r o l e  would be p a r t i c u l a r l y  1981;  the  in  the  Competition  between  soluble  and  b i o a v a i l a b i l i t y and will  determine  the  m o b i l i t y of t r a n s i t i o n metals i n s o i l s .  They  e v e n t u a l l y be t r a n s p o r t e d  their  d i s s o l v e d f r a c t i o n can  associations Turekian,  from  P a c i f i c Ocean  indications and  traps  and  Swaine,  that  Calvert  et a l . ,  deployed  by  Greenslate 1978).  i n the  with organic  This  Cu,  is  Coker,  et a l . ,  1980; 1985).  post-depositional  matter  metal-organic et. a l . ,  Morris,  of some t r a n s i t i o n the  H a r r i s , 1974;  1977;  humic  1980;  processes 1977)  (e.g.  fraction  Chen,  Hirata,  Coker, 1980)  is s t i l l  debate.  Here again, metal-humic a s s o c i a t i o n w i l l be  and 1977; 1985;  acquired or through  Nissenbaum  1976;  are  metals,  Nissenbaum  Knezevic and  (e.g. Nriagu and  and M o r r i s ,  depth,  there  Whether t h i s metal content i s  a matter  and of  important i n  b i o a v a i l a b i l i t y of t r a n s i t i o n metals.  evidence for metal-humic a s s o c i a t i o n s  pore waters (Nissenbaum and  North  with  Swaine,  is  by  collected  Tropical  increases  H a l l b e r g et a l . ,  r e g u l a t i n g the m o b i l i t y and  1973;  i s supported  In marine sediments,  Cooper and  diagenetic  Calvert  Eastern  a s s o c i a t e d with  C a l v e r t and  from the o v e r l y i n g water  There  removal of  which showed that the amount  a large proportion  Fomina, 1972;  1976;  Nriagu and  1955;  through scavenging.  particularly  (Volkov  a l s o be mediated  ( F i s c h e r et a l . , 1986)  associated  presumably  will  l e a c h i n g of s e t t l i n g p a r t i c u l a t e m a t e r i a l s  sediment  Cu  Bostrom  ligands  to the oceans where the  (Revelle et a l . ,  1977;  sequential  of  insoluble  Swaine,  14  1976;  in  Krom and  sedimentary Sholkovitz,  1978; by  Lyons et al.,1979; E l d e r f i e l d , 1981) and t h i s has been used  some  authors t o e x p l a i n the occurrence of metals  in  anoxic  pore waters at c o n c e n t r a t i o n s h i g h e r than p r e d i c t e d from s u l p h i d e mineral e q u i l i b r i a (Brooks et a l . ,  1968; P i p e r ,  al.,  1975).  1972; E l d e r f i e l d and Hepworth,  As d i s c u s s e d throughout t h i s b r i e f review, are  of  paramount  biogeochemistry.  importance However,  many i n s t a n c e s ,  still  recent e s c a l a t i n g  i n many aspects  our  field:  frustrating, materials, directly  i s , in  working  with  humic  always l a b o r i o u s and seldom so widely d i s t r i b u t e d  materials rewarding.'  is  often  Yet,  these  on the e a r t h ' s s u r f a c e ,  or i n d i r e c t l y many r e a c t i o n s that a f f e c t man's  I s h a l l present here a somewhat f r u s t r a t i n g , hopefully still  rewarding to  from  To quote a l e a d i n g a u t h o r i t y i n  i n g e n u i t y of s c i e n t i s t s of many d i s c i p l i n e s . "  problems  environmental  i n humic substances by s c i e n t i s t s  on t h i s p l a n e t and they continue t o c h a l l e n g e  yet  of  f a r from adequate. T h i s should j u s t i f y the  interest  "...  humic substances  knowledge of t h e i r r o l e  a wide d i v e r s i t y of d i s c i p l i n e s . the  1971; P r e s l e y et  survival  the c u r i o s i t y (Schnitzer, certainly  attempt a t s o l v i n g a few of  be addressed i n the  control  geochemistry  and  1978).  laborious, the many of  humic  materials.  1.2 SYNOPSIS OF THE PRESENT STUDY. In the present work,  three d i f f e r e n t  investigated: 15  but r e l a t e d  t o p i c s are  1.2.1  SULPHUR IN THE HUMIC FRACTION OF MARINE SEDIMENTS. The  fraction  of  evolution  of  the sulphur content  a near-shore marine sediment  was  in  the  investigated.  a p p r o p r i a t e e x t r a c t i o n procedure designed to meet the requirements analyses the  of t h i s study was  were performed  possible  developed.  involved  in  the  An  particular  Chemical and  on the e x t r a c t e d m a t e r i a l  mechanisms  humic  to  isotopic constrain  observed  sulphur  enrichment.  1.2.2 OF  THE  INFLUENCE OF HUMIC SUBSTANCES ON THE  GEOCHEMISTRY  IODINE IN MARINE SEDIMENTS. Iodine  shore  i s c h a r a c t e r i s t i c a l l y e n r i c h e d i n s u r f a c e near-  and hemipelagic sediments  Pavlova,  1965;  P r i c e et a l . ,  Pedersen and P r i c e , investigated sediments and Based  (Vinogradov,1939; 1970;  P r i c e and  S h i s h k i n a and Calvert,  1980). T h i s aspect of i o d i n e geochemistry  was  by determining the p a r t i t i o n i n g of i o d i n e i n marine  and by performing l a b o r a t o r y experiments  on the  r e l e a s e of i o d i n e by and from sedimentary humic on these r e s u l t s ,  substances  1977;  at  substances.  a mechanism f o r i o d i n e uptake  the sediment/water  r e l e a s e upon b u r i a l i s proposed.  16  i n t e r f a c e and  its  uptake  by  humic  subsequent  1.2.3  METAL  ENRICHMENT  IN SEDIMENTS DEPOSITED  IN ANOXIC  BASINS.  observed Price,  An  enrichment  in  modern o r g a n i c - r i c h anoxic sediments  1970;  Volkov  of c e r t a i n t r a c e metals has  and  mechanism of enrichment, depletion  , is s t i l l Bulk  statistical  Fomina,  1972,  often (Calvert  and  1976).  The  Calvert,  c o n s i d e r e d to be a s s o c i a t e d with oxygen-  e s s e n t i a l l y unknown.  sediment  analyses  often  show  a  distinct  c o r r e l a t i o n between metal c o n c e n t r a t i o n s and organic  carbon content and t h i s has sometimes been taken as an of  a d i r e c t a s s o c i a t i o n with organic matter  and  Fomina,  correlation leading  1972). could  However,  also  metals without d i r e c t  used  pattern  monthly seasonal  set  Volkov  that  of  cannot  in  matter  and  association.  which are the  be  in  solely  the fjord  S t a t i s t i c a l a n a l y s i s has been elements  explained  in  whose terms  Settling  particulate  materials  Saanich  Inlet using  interceptor  distribution of  have  sediment also  traps  over an 18 month p e r i o d at three d i f f e r e n t variations  this  conditions  of Saanich I n l e t , an i n t e r m i t t e n t l y anoxic  determine  mineralogy. collected  1966;  recognized  be the r e s u l t of a  the coast of B r i t i s h Columbia. to  was  indication  s i m i l a r d i s t r i b u t i o n p a t t e r n has been sought  s u r f a c e sediment on  it  (Curtis,  to the simultaneous accumulation of organic  A  been  been  deployed  depths.  i n the f l u x e s of o r g a n i c matter and  The  various  metals were determined. These samples were a l s o compared with the 17  sediment  data  which r e g u l a t e  Although problems,  I  i n an attempt to e v a l u a t e the  different  factors  the metal c o n c e n t r a t i o n s i n these sediments.  each  of  these  sections  addressed  have been a b l e to demonstrate a c e r t a i n  interdependence between the v a r i o u s processes i n v o l v e d .  18  different degree  of  2. SULPHUR  IN  THE  HUMIC  SUBSTANCES  OF  NEARSHORE  MARINE  SEDIMENTS.  2.1 INTRODUCTION.  It  has been argued  humic substances conditions  from  that the sulphur content of marine environments  prevailing  during  their  Kaplan,  1972;  Stuermer et a l . ,  weight)  of marine plankton l i e s  reflects  formation  1978).  While  the  s i g n i f i c a n t l y higher values (up to 0.10)  in  sedimentary  materials,  redox  (Nissenbaum the S/C  have been  particularly  and  ratio  i n the range 0.010-0.030  2),  humic  sedimentary  (by  (Table reported  from  anoxic  sediments. The  most  commonly accepted pathway  sulphur i n t o organic matter so  formed  is  polysaccharide thioethers  is biosynthesis.  sulphate  esters,  (Kharasch and Aurora,  amino a c i d s and p r o t e i n s .  and  their  alternative added  incorporation The  found at a l l o x i d a t i o n s t a t e s , to  organic sulphur  from as  in  +6,  as  thiols  in and  with subsequent formation of  However, c o n s i d e r i n g the r e a c t i v i t y of  sulphur s p e c i e s ,  particularly  abundance i n sedimentary pathways  -2,  of  1976). The main process i n v o l v e d  i s a s s i m i l a t o r y sulphate r e d u c t i o n ,  inorganic  for  HS  marine  through which sulphur  and  polysulphides,  environments, can  be  three  chemically  to the organic matrix should a l s o be c o n s i d e r e d ( F i g . 19  2).  Table 2: C and S content  of p l a n k t o n i c m a t e r i a l s .  References  % C  % S  S/C  22.5  0.6  0.027  Vinogradov* (1953)  -  0.3  -0.013  Kaplan et a l . (1963)  45.4-49.7  0.5-0.7  0.010-0.015  P h i l p and C a l v i n (1976)  Green algae (C. pyrenoidosa)  51.4  0.7  0.014  P h i l p and C a l v i n (1976)  Diatom _ (T. pseudonana)  35.1  0.82  0.023  T h i s work  18.7  0.37  0.020  This work  53.5 55.7  0.72 0.76  0.013 0.014  This work This work  Marine  plankton  Dinoflagellate (G. polyhedra) Blue-green algae (N. muscorum, A. n i d u l a n s , P. luridium)  Near-shore marine p l a n k t o n (mixed population)  3  "Humic a c i d s " e x t r a c t e d f r o m a mixed p o p u l a t i o n  4  1  1 - C i t e d i n Bowen (1979) 2 - T. pseudonana was grown t o e a r l y senescence i n batch culture using artificial seawater (Harrison e t a l . , 1980). A f t e r concentration in a continuous c e n t r i f u g e , the sample was d i a l y s e d against d e i o n i z e d water t o e l i m i n a t e seawater s u l p h a t e s , f r e e z e - d r i e d and homogenized before elemental analysis. 3 - This sample was obtained by v e r t i c a l haul during a s p r i n g bloom i n Saanich I n l e t . I t had been f r e e z e - d r i e d and s t o r e d s e v e r a l months before being dialyzed. 4 - The above f r e e z e - d r i e d plankton p o p u l a t i o n was t r e a t e d with 0.5N NaOH under n i t r o g e n f o r 18hrs. The m a t e r i a l e x t r a c t e d was a c i d i f i e d t o pH 1.5-2 with HC1. HP (0.1M) was added t o reduce the ash content of the p r e c i p i t a t e . After c e n t r i f u g a t i o n and s e v e r a l r i n s i n g s , the sample was f r e e z e - d r i e d and analyzed. The two s e t s of f i g u r e s correspond t o two succesive e x t r a c t i o n s of the same sample.  20  oxidation ( b a d ./chem.)  Fig.  2:  21  Sulphur  cycle.  The  light  isotopic  sedimentary sulphur  composition  humic substances  enrichment  of  the  which  has  would support organic  been  i s occurring v i a  reactions  between the organic matrix and H S- (or  products)  produced  i t s oxidation  2  potential  by d i s s i m i l a t o r y sulphate  reduction  during  1972). However, a great  e x i s t s f o r sulphur contamination  of the  Pyrite  i s an u b i q u i t o u s component of such sediments and a  and  various  sulphur,  sulphur  sulphur  polysulphides),  naturally  Mango,  during content  sediments.  r e a c t i o n s are p o s s i b l e between o r g a n i c  inorganic  Pryor, • 1962;  anoxic  matrix  sample  of chemical  and e x t r a c t i o n from  humic  during  range  handling  species  (sulphides,  wide matter  elemental  most of which are b a s e - c a t a l y z e d (e.g.  1983).  early  in  the hypothesis that a  matter  e a r l y d i a g e n e s i s (Nissenbaum and Kaplan,  found  Although  these r e a c t i o n s may occur  d i a g e n e s i s and  and l i g h t  may  explain  i s o t o p i c composition  of  the  high  sedimentary  humics, they w i l l be g r e a t l y a c c e l e r a t e d during humic e x t r a c t i o n , which  i s generally  conditions.  performed under  fairly  strongly  T h e r e f o r e , some s i g n i f i c a n t a r t i f i c i a l  alkaline  enrichment of  the humics c o u l d r e s u l t d u r i n g the e x t r a c t i o n step and the extent of the n a t u r a l sulphur enrichment c o u l d be obscured. Confirmation formed  of  sulphur-enrichment  in  humic  i n marine sediments using an e x t r a c t i o n  w i l l minimize these contamination confirmed, complement  the  mechanism(s)  procedure  problems i s s t i l l of  such  an  substances which  required. If  enrichment  would  our knowledge of sulphur t r a n s f o r m a t i o n s during e a r l y 22  diagenesis involved al.,  and  the  in the  1979;  importance of d i f f e r e n t r e a c t i o n  i n c o r p o r a t i o n of sulphur  Casagrande and Ng,  derived  from d i f f e r e n t organic  1984).  Understanding  matter  may  metal  since  observed  et a l . , 1982;  2.2  i n many anoxic  et  i n t o marine for  a  c l a s s "B"  suitable  al.,  organic  the  sediments  t h i o l groups are p a r t i c u l a r l y  marked  (Calvert, complexing  metals (e.g. Emerson  Boulegue et a l . , 1982).  EVALUATION OF THE  SUBSTANCES  f a c i e s (Demaison  on explanations  f u n c t i o n a l i t i e s f o r t r a n s i t i o n and  provide  et  observed between kerogen  incorporation  a l s o have a bearing  enrichment  1976),  sulphur  (Casagrande  1979). Moreover, i t may  b a s i s f o r e x p l a i n i n g the marked c o n t r a s t types  in c o a l  mechanisms  NECESSARY  EXTRACTION CONDITIONS OF TO ESTIMATE THEIR  SEDIMENTARY HUMIC  TRUE,  IN-SITU  SULPHUR  true,  in-situ  sulphur  CONTENT.  2.2.1. INTRODUCTION.  The  difficulty  content  of  in estimating  the  marine sedimentary humic substances r e s i d e s  presence, in the sediments, of l a r g e amounts of reduced sulphur during  s p e c i e s which w i l l  section  describes  the  inorganic  react r e a d i l y with the organic  an a l k a l i n e e x t r a c t i o n  This  in  matrix  step. a  23  series  of  observations  and  experiments designed t o test marine  sedimentary  extraction.  An  the s u l p h u r c o n t a m i n a t i o n of  anoxic  humic s u b s t a n c e s d u r i n g s a m p l e h a n d l i n g a n d  extraction  s e r i e s of chemical r e a c t i o n s  scheme i s o u t l i n e d  which  avoids  i n d u c e d by t h e e x t r a c t i o n  a  conditions  which l e a d t o the c o n t a m i n a t i o n .  2.2.2  MATERIALS AND METHODS.  Sediment  samples  were c o l l e c t e d  f r o m two B r i t i s h  i n l e t s u s i n g t h e l i g h t w e i g h t g r a v i t y c o r e r d e s c r i b e d by et  a l . (1985).  The  c o r e s were e x t r u d e d i n  glove-box  and  subsequent  analysis or experimentation.  Inlet,  into  appropriate  c o l l e c t e d a t a d e p t h o f 220 m,  conditions volatile Inlet  sulphides  (AVS) a n d p y r i t e .  accumulated  surface  conditions  layer  sediment carbon  at  types  a  depth  of  subsamples from  anoxic  sulphide,  acid-  The s e d i m e n t s f r o m 650  m  under (~1  Jervis  permanently cm)  o v e r l y i n g a s u b o x i c and a s u l p h i d i c roughly equivalent  for  Saanich  a c c u m u l a t e d under  and c o n s i s t of a t h i n  contain  Pedersen  nitrogen-filled  Sediments  and c o n t a i n h i g h l e v e l s of hydrogen  oxygenated  amounts  oxidized  layer. of  Both  organic  (~3-4%).  The nitrogen humic  partitioned  a  Columbia  humic s u b s t a n c e s were e x t r a c t e d by 0.5 N NaOH, atmosphere,  acid  fraction  on an a u t o m a t i c s h a k e r f o r 18 (HA) was f u r t h e r  24  isolated  by  under  hours.  a The  acidification  to pH2  with HC1,  The carbon by  gas  and the p r e c i p i t a t e was f r e e z e - d r i e d . content of the e x t r a c t e d f r a c t i o n s was  chromatography using a C a r l o Erba Model  determined  1106  Elemental  Analyzer and using a c e t a n i l i d e as a standard. P r e c i s i o n was at  the  95% confidence l e v e l .  T o t a l sulphur was  determined  amperometric t i t r a t i o n a f t e r combustion of the sample , F i s h e r Model 475 S u l f u r Analyzer precision  was  co-extracted few mg  +5%  (Guthrie and  with the humic a c i d s ,  of the humic m a t e r i a l with  solution  a c c o r d i n g to Zhabina  The p r e c i s i o n was  +8%  the humic e x t r a c t s was Erba Analyzer  Lowe,  at the 95% c o n f i d e n c e l e v e l . was  by  using  1984).  Pyritic  a The  sulphur,  estimated by t r e a t i n g  1ml of a f r e s h l y prepared  and Volkov  +2.5%  (1978)  (Appendix  at the 66% c o n f i d e n c e l e v e l . measured by dry-combustion  a  CrCl  2  II).  The D.O.C. of using the C a r l o  (Appendix I I ) .  Elemental  sulphur was  e x t r a c t e d by benzene  and measured by  c y a n o l y s i s a c c o r d i n g to B a r t l e t t and Skoog (1953) (Appendix I I ) . F o u r i e r - T r a n s f o r m Infra-Red s p e c t r a of humic a c i d s were made on a N u j o l mull with a N i c o l e t  2.2.3  RESULTS AND  5-DX  Analytical  Spectrophotometer.  DISCUSSION  2.2.3.1 CONTAMINATION  OF THE  HUMIC FRACTION EXTRACTED FROM  A SULPHIDIC SEDIMENT BY CO-EXTRACTED PYRITE. If  pyrite  i s present  i n the examined sediment i n  25  a  fine-  g r a i n e d , h i g h l y d i s p e r s e d form, i t c o u l d be c o - e x t r a c t e d with the humic  acids.  This  potential  contamination  problem  was  i n v e s t i g a t e d by t r e a t i n g the humic a c i d s e x t r a c t e d from an anoxic sediment was  with a f r e s h l y prepared C r C l  shown by Zhabina  while  leaving  obtained  and Volkov  2  solution.  Such  (1978). to produce H S unaffected.  The  when using t h i s method on p y r i t e of known  (ground  and mixed with g r a n i t e ) and  shown i n Table An  under a stream Elemental  After  were  from Saanich I n l e t  2  treatment  error  2.2.3.2  the humic  and t h e i r p y r i t i c  produced.  Table 3 show that p y r i t e contamination  The  results  can be  a  0.5N acids  sulphur presented  substantial  i n the d e t e r m i n a t i o n of the sulphur content  humic a c i d s e x t r a c t e d from  THE  removed from the d r i e d sediment  measuring t h e i r S and C c o n t e n t s ,  2  of  was  the humic a c i d s were e x t r a c t e d with  s u b j e c t e d to the C r C l  source  at room 2  sulphur was  finally  0.1N  was  of n i t r o g e n u n t i l no f u r t h e r H S  estimated from the amount of H S in  recoveries  50.  with benzene and NaOH.  2  stochiometry  t r e a t e d , w i t h i n two hours a f t e r c o l l e c t i o n , with HC1  produced.  FeS  some p l a n k t o n i c m a t e r i a l are  anoxic sediment sample c o l l e c t e d  temperature  from  2  the organic sulphur  treatment  sulphidic  of  sediments.  SULPHUR CONTAMINATION OF THE  HUMIC FRACTION  DURING  OXIDATION OF ANOXIC SEDIMENTS. When an anoxic sediment i s i n c o n t a c t with the oxygen of the  atmosphere d u r i n g storage or d r y i n g , 26  some H S 2  and a c i d  volatile  Table 3. P y r i t e contamination of humic a c i d s e x t r a c t e d from an anoxic sediment. % wt i n humic a c i d s ^ C 34.8+0.4  1. 2. 3. 4.  S t  S py  2  b  3  b  3.01+0.07  1.00+0.08  Not ash c o r r e c t e d T o t a l sulphur P y r i t i c sulphur Organic sulphur (S.-S )  27  S  4  2.01+0.11  sulphides  (A.V.S.)  will  be o x i d i z e d to elemental  sulphur  and  p o l y s u l p h i d e s w i l l be formed as an intermediate (Chen and M o r r i s , 1972;  Chen and Gupta,  homolytically react  with  1973).  and produce f r e e r a d i c a l s which c o u l d organic  eventually t h i o l  matter  to form  evaluated  organic  was  in  the  in a i r ,  following  experiment.  and  split  A  T h i s treatment  elemental  sulphur produced  removed with benzene and under n i t r o g e n .  t o t a l of 50 hours and d r i e d and sulphur formed  anoxic  thoroughly homogenized  i n t o two  subsamples. One  under a n i t r o g e n stream  produced.  0.5N  and  processes  fresh  t r e a t e d w i t h i n two hours a f t e r c o l l e c t i o n with 0.1N  room temperature,  ratio  polysulphides  of humic a c i d s v i a such  sediment sample from Saanich I n l e t was a blender,  conceivably  groups.  The p o s s i b l e contamination was  P o l y s u l p h i d e s are r e a d i l y c l e a v e d  until ^ S  removed the A.V.S..  in  subsample HC1,  stopped  at  being  After drying,  i_n s i t u and by the a c i d treatment  the was  the humic a c i d s were e x t r a c t e d with NaOH  The  second  subsample was  left  in a i r for a  f r e e z e - d r i e d before being t r e a t e d with HCl,  the humic a c i d s e x t r a c t e d as b e f o r e . I f the a d d i t i o n of to  the organic matrix by  during  storage was  significant,  of the humic substances  recorded.  The  reaction  for p y r i t i c  polysulphides  i n c r e a s e i n the  e x t r a c t e d a f t e r 50 hours would  r e s u l t s shown i n Table 4 i n d i c a t e that under  c o n d i t i o n s of storage which were used contamination  an  with  be the  (room temp., 50 hours) such  i s n e g l i g i b l e s i n c e the S/C  sulphur) stayed e s s e n t i a l l y 28  S/C  ratio  (after  constant.  correction  However,  the  Table 4. S/C r a t i o of humic a c i d s e x t r a c t e d from an anoxic sediment after different intervals of a i r exposure.  Wt% i n HA C  S  2 h r s a i r exposure  34.8+0.4  2.01+0.11  0.058+0.003  50 h r s a i r exposure  39.1+0.4  2.37+0.20  0.061+0.005  1. C o r r e c t e d  for p y r i t i c  sulphur.  29  1  S/C  possibility  that  an a r t i f i c i a l  sulphur enrichment  would  a f t e r a longer time of storage or at higher temperature  occur  cannot  be  r u l e d out.  2.2.3.3 REACTIONS  SULPHUR WITH  CONTAMINATION  VARIOUS  SULPHUR  OF  HUMIC  SPECIES  SUBSTANCES  DURING  BY  ALKALINE  EXTRACTION. 2.2.3.3.1  SULPHUR CONTAMINATION BY SULPHIDES:  As a p r e l i m i n a r y t e s t , from  a f r e s h l y c o l l e c t e d anoxic  sediment  Saanich I n l e t was thoroughly homogenized under n i t r o g e n and  split  into  extracted  two with  subsamples. NaOH 0.5N  other was f i r s t  One  subsample  (18 hours,  was  immediately  under n i t r o g e n ) while  the  s u b j e c t e d to an a c i d pre-treatment  (HC1 0.1N,room  temperature) before a s i m i l a r a l k a l i n e e x t r a c t i o n .  The elemental  composition the  extent  extracted Further for  of these humic a c i d s ,  in  of  sulphur  the  shown i n Table 5, demonstrates  contamination  presence  of s u l p h i d e s  when ( S H  2  humic and/or  t e s t s to i n v e s t i g a t e the p o s s i b l e r e a c t i o n s  t h i s sulphur enrichment  2.2.3.3.1.1  were  acids  are  A.V.S.).  responsible  undertaken.  REACTIONS BETWEEN FREE SULPHIDES AND HUMIC ACIDS IN  BASIC SOLUTIONS: Sulphide anions a r e powerful n u c l e o p h i l e s which w i l l  readily  react with organic f u n c t i o n a l i t i e s c o n t a i n i n g a carbon atom  30  with  Table 5. Sulphur contamination by s u l p h i d e s d u r i n g a l k a l i n e e x t r a c t i o n of humic a c i d s .  the  Wt% i n HA C  S  S/C  No HC1 pretreatment  37.2+0.4  7.48+0.19  0.201+0.006  With HC1 pretreatment  43.6+0.4  3.50+0.09  0.080+0.003  1 . Not ash c o r r e c t e d .  31  an e l e c t r o n d e f i c i e n c y , e s p e c i a l l y at high pH, v i z HS:  +  X=Z  >  C  Z  represents an  + HZ  type of r e a c t i o n w i l l  ,  (1)  '  electron-withdrawing  producing a p a r t i a l p o s i t i v e charge This  C=S  SH  ^^/cT  where  >  (h )  functionality  on the adjacent  +  take p l a c e with  carbon.  functionalities  c o n t a i n i n g c a r b o n y l groups such as aldehydes  (Campaigne, 1961)  or  perhaps  Michard,  In  ketones  addition, double  such  bond,  A  a  (Boulegue  and  r e a c t i o n c o u l d take p l a c e on a  a c t i v a t e d by c o n j u g a t i o n to an  functionality lactones  and quinones  such as i n o ( ,  set of experiments  electron-withdrawing  1976;  was  Boelens  performed  to  with a humic a c i d e x t r a c t e d from an from  removed.  The  split was  which  elemental  humic f r a c t i o n  i n t o two p a r t s .  N a  2  S  kept as a c o n t r o l . The  overnight and a c i d i f i e d  w  a  by a l l o w i n g s u l p h i d e anions  sulphur  solubilized  s  two  to pH2  or  to check f o r evidence of  i n v o l v i n g free s u l p h i d e s ,  sediment  aldehydes  et a l . , 1979).  reactions react  carbon-carbon  unsaturated ketones,  (Kharasch and Aurora,  1974).  had  air-dried been  anoxic  previously  from t h i s sediment  was  added to one p a r t while the other s o l u t i o n s were kept under n i t r o g e n under a v i g o r o u s n i t r o g e n  stream.  The p r e c i p i t a t e d humic a c i d s were then analyzed for t h e i r C and S contents. the  The  humic  samples. exposed  results  acids This  to  (Table 6) show that the sulphur content of  increases s i g n i f i c a n t l y  occurs  in  the  Na2S-treated  with humic a c i d s which have a l r e a d y  n a t u r a l l y high l e v e l s of 32  sulphide.  The  degree  been of  Table 6. Sulphur enrichment of humic sulphide ions i n a l k a l i n e s o l u t i o n s .  acids  by  Wt% i n HA C  S  S/C  HA - no Na S  30.2+0.4  1.79+0.05  0.059+0.002  HA + 2mM Na,S  13.2+0.2  1.02+0.03  0.083+0.003  HA - no Na S  51.8+0.5  3.37+0.08  0.065+0.002  HA + 20mM Na S  46.8+0.5  9.84+0.25  0.210+0.006  HA - no Na S  49.3+0.5  2.80+0.07  0.057+0.002  43.5+0.5 15.45+0.39  0.355+0.010  2  2  9  2  HA + 20mM Na S 2  1. Not ash c o r r e c t e d .  33  enrichment  clearly  depends on the ambient s u l p h i d e  shown by the treatments In  addition,  the  with 2 and  sulphur  levels,  20 mmol/1 s u l p h i d e  enrichment  observed  solutions.  in  the  materials  with low ash content confirms that the organic  than  inorganic  the  fraction  i s responsible  for  as  humic rather  this  sulphur  enrichment. 2.2.3.3.1.2 AND  REACTIONS BETWEEN ACID VOLATILE SULPHIDES  (A.V.S.)  HUMIC ACIDS IN BASIC SOLUTIONS: Since  metals,  a l l the s u l p h i d e s present  it  chemically  is  unlikely  that  i n the A.V.S.  they  would  with the organic matrix.  A.V.S.  with  Easily  decomposable  be  However,  able  such  as  to  react  co-extraction  humic m a t e r i a l s i s o c c u r r i n g to a A.V.S.,  are bound to  certain  of  extent.  mackinawite,  will  be  decomposed d u r i n g the a c i d p r e c i p i t a t i o n of humic a c i d s . However, more  resistant  more  drastic  elimination.  sulphide minerals acid  Sulfate-esters,  humic m a t e r i a l s (e.g. al., Klug,  1983)  treatment  are  (e.g. (HC1  which  Tabatabai and  greigite) will 1N,boiling)  require a  for  their  are known to be present Bremner, 1972;  in  A l t s c h u l e r et  s u s c e p t i b l e to a c i d h y d r o l y s i s (e.g.  King  and  1980), and t h e r e f o r e such a s t r o n g a c i d pre-treatment  must  3+ be avoided. from  the  A l s o , during the removal of A.V.S., Fe sediment and o x i d i z e s some of the  elemental polysulphides  sulphur, could  possibly then  react 34  HS 2  i s released produced  via  polysulphides.  with  humic  materials  into These and  artificially  increase t h e i r  sulphur  An anoxic sediment c o l l e c t e d dried  and  d i v i d e d i n t o two  t r e a t e d with 0.1N prior  to  removal while  the  elemental  at room temperature, (which was  sulphur produced  present. A f t e r p r e c i p i t a t i o n , the  treatment  (Zhabina  humic  s u l p h i d e produced results  difference  and Volkov,  seem  hydrolysis negligible The  by the  after  acid  by the decomposition -  presented  in  the  treatment) with  the  elemental  to  a  C r C  i n order to estimate  l2 the  included  of c o - e x t r a c t e d g r e i g i t e .  Table  7  of A.V.S. or a f t e r a 0.1N  to i n d i c a t e t h a t ,  under the  show  no  significant  and or,  contamination which  large further  by  of  pre-treatment.  conditions  polysulphides)  i s less l i k e l y ,  amount  HC1  This  used,  the  by A.V.S., e s t e r sulphate  sulphur  are  either  e x a c t l y compensate released  by  the  each CrC^  i l l u s t r a t e s the need f o r the d e t e r m i n a t i o n  the amount of c o - e x t r a c t e d a c i d - r e s i s t a n t 2.2.3.3.2  performed  This determination a l s o  processes d i s c u s s e d ( i . e . contamination  treatment  to remove the A.V.S.  f r e e z e - d r y i n g and  1978)  was  i n the sulphur content of humic a c i d s e x t r a c t e d e i t h e r  in the presence  other.  of the samples  a c i d s were f u r t h e r s u b j e c t e d  amount of c o - e x t r a c t e d p y r i t e .  The  One  freeze-  other sample had the humic a c i d s e x t r a c t e d  analysis,  would  from Saanich I n l e t was  subsamples.  humic a c i d e x t r a c t i o n of  A.V.S.  HC1,  content.  of  sulphide species.  SULPHUR CONTAMINATION BY ELEMENTAL SULPHUR:  Elemental sulphur  i s present  35  i n most marine sediments.  It i s  T a b l e 7. I n f l u e n c e o f t h e p r e s e n c e a n d r e m o v a l s u l p h u r c o n t e n t o f e x t r a c t e d humic a c i d s . Wt% Humic a c i d s  extracted  from:  C  S  o f t h e A.V.S. on t h e  i n HA S  S/C  - F r e e z e - d r i e d sediment ( w i t h A.V.S. p r e s e n t ) .  35.2+0.4 2.11+0.17 2.28+0.20 0.065+0.006  - F r e e z e - d r i e d and a c i d t r e a t e d s e d i m e n t (no A.V.S. p r e s e n t ) .  39.1+0.5  1. Not a s h c o r r e c t e d .  36  1.93+0.15 2.37+0.19 0.061+0.005  also  formed by the o x i d a t i o n of t^S and A.V.S.  drying  or a c i d treatment of s u l p h i d e - b e a r i n g  therefore  necessary  contamination sulphur  of  storage,  sediments.  t o i n v e s t i g a t e the p o s s i b i l i t y  humic substances by r e a c t i o n s  under s t r o n g l y b a s i c  The  during  It  of  with  was  sulphur elemental  conditions.  S-S bonds of the s t a b l e S  r i n g s of elemental sulphur can  g  be attacked by: (a) n u c l e o p h i l i c s p e c i e s , v i z Nu:~ + S (b) e l e c t r o p h i l i c E  > Nu-S -S~  g  7  species, v i z  + Sg  +  (2)  > E-S -S  +  ?  (3)  or (c) f r e e r a d i c a l s , v i z R• The Because  like  most l i k e l y of  electron  + Sg  > R-S -S?  r e a c t i o n i n the present  a Lewis a c i d ( i . e . by  the  reactions  humic  such  follows  elemental sulphur  between  R  fc  37  /N-S~  might  + H  +  be  (5)  16  more  base,  (Pryor,  Sg and n u c l e o p h i l i c  as amines and t h i o l s  (see Schumann, 1972): R ' — S ^NH +*I^S >  Sg  the  acts  an e l e c t r o n acceptor) than a  c y a n o l y s i s r e a c t i o n of  Accordingly, acids  case would be ( 2 ) .  the presence of f r e e d - o r b i t a l s and d e s p i t e  doublets on the Sg r i n g ,  illustrated  (4)  as  1962).  groups  of  possible  as  Furthermore,  the  polysulphides  so  produce f r e e r a d i c a l s , through homolytic R R  >  S  8  —">  > 8-X S  R  > AA  S  A A  between  r e a c t i o n between Sg and  Of  S  to c o n t a i n  (Martin  + HS~  (8)  Y (9)  elemental  and Hodgson,  humic a c i d s has  sulphur 1977)  have  and  been  a  rapid  been demonstrated at room  1979). sulphur  and  f r e e r a d i c a l s ( r e a c t i o n ( 4 ) ) . Humic a c i d s  are  f r e e r a d i c a l s which appear to be r e l a t e d to  the  character  particular  viz  ( 7 )  p o s s i b l e r e a c t i o n i n v o l v i n g elemental  humic a c i d s i s v i a  aromatic  *X  +  A/V  amines and  (Casagrande and Ng,  Another  known  >  +*Sy  experimentally  temperature  readily  in turn react with organic matter, v i z  A A + *s~  shown  cleavage,  could  R  which c o u l d  Reactions  formed  of these substances (Stuermer et a l . ,  relevance  here i s the reported  increase  in  1978). free  r a d i c a l number for sodium humate ( S c h n i t z e r and Skinner, 1969). These free r a d i c a l s could c o n c e i v a b l y open the Sg rings to produce open-chain organic marine  humic  acids  polysulphides.  contain  ESR  approximately  38  s t u d i e s show that 17 2x10 spins/g.C  (Stuermer e_t a l . , site  was  1978).  Therefore,  even i f every f r e e  a s s o c i a t e d with 8 sulphur  atoms,  radical  t h i s would  produce  only an enrichment o f , v i z 2X10  1 7  x 8 x 32 _  =  _o.OOOlg.S/g.C  6X10V;T h i s simple c a l c u l a t i o n i n d i c a t e s that there are not free  radicals  sulphur  order  sulphur  to  a i r - d r i e d anoxic  sulphur acids  removal  content  in  chemically  bound  of  significant  between  of humic m a t e r i a l s before  elemental acids  extracted  from  and a f t e r elemental  was determined.  the presence of S  removal  a  the e x t r a c t i o n of humic  sediment sample,  r e l a t i v e to carbon,  exhaustive  reactions  from the sediment,  extracted  sulphur,  matter during  the sulphur  produce  mechanism.  check p o s s i b l e  and organic  with NaOH,  an  humic substances to  enrichment by t h i s  In  an  in  enough  contain  The  twice  humic  as  much  as the humic a c i d s e x t r a c t e d a f t e r S  (Table  8).  to the humic matrix,  This  since i t  sulphur could  not  was be  removed by benzene e x t r a c t i o n . 2.2.3.3.3  REACTIONS BETWEEN POLYSULPHIDES AND HUMIC  SUBSTANCES  IN BASIC SOLUTIONS: In  the  experiment conducted t o i n v e s t i g a t e  between p o l y s u l p h i d e s to  react  (collected  in  and humic a c i d s ,  the presence of  an  from J e r v i s I n l e t ) d u r i n g  39  Na S and S°  oxic,  2  the  reactions  were  freeze-dried  allowed sediment  the humic a c i d e x t r a c t i o n i n  Table 8. Sulphur enrichment in a l k a l i n e solutions.  of humic a c i d s by elemental  sulphur  Wt% i n HA C  S  S/C  HA e x t r a c t e d a f t e r elemental sulphur e x t r a c t i o n .  34.1+0.4  2.4+0.1  0.070+0.002  HA e x t r a c t e d i n presence elemental s u l p h u r .  42.5+0.5  5.8+0.2  0.136+0.004  of  1. Not ash c o r r e c t e d .  40  NaOH.  The r e s u l t s are shown i n Table 9.  presence of elemental content had  As a l r e a d y  sulphur can s i g n i f i c a n t l y a l t e r  of the e x t r a c t e d humic a c i d s .  a smaller although  still  of  S°  being  significant effect,  presumably due  However,  This i s  2  r e s u l t of the formation  f r e e r a d i c a l s which then  alone  2  and Na S d u r i n g the e x t r a c t i o n .  producing Since  the sulphur  the l a r g e s t  i n the S/C r a t i o was produced by the combined  the  the  The presence of Na S  to i t s r a p i d o x i d a t i o n by the i r o n oxides. increase  noted,  of  presence  interpreted  inorganic  polysulphides  react with the organic  matrix.  these humic a c i d s were p r e c i p i t a t e d by a c i d i f i c a t i o n ,  newly-formed  organic sulphur groups could not have been  polysulphides,  which are decomposed at low pH,  have been a c i d r e s i s t a n t S - c o n t a i n i n g the h y d r o l y s i s and/or homolytic produced  as  extracted  an  from  1  the  organic  but i n s t e a d must  f u n c t i o n a l groups formed by  cleavage  intermediate.  as  I.R.  of organic spectra  and 3 (Table 9) are  polysulphides  of  shown  humic  acids  i n F i g . 3. These  samples d i s p l a y e d the usual I.R. f e a t u r e s g e n e r a l l y r e p o r t e d from such s p e c t r a . have  The strong a b s o r p t i o n s at 1720 cm  and 1640  been a t t r i b u t e d to C=0 s t r e t c h i n g v i b r a t i o n s of  and  amide groups (Stevenson  and Goh,  1971;  while the a b s o r p t i o n bands i n the 1200-1090 cm interpreted 1980) The  1  as C-0 s t r e t c h of p o l y s a c c h a r i d e s  1  carboxylic  Ishiwatari,  1972),  region have been  1  (Hatcher  e_t a l . ,  or S i - 0 s t r e t c h i n g v i b r a t i o n s (Whitby and S c h n i t z e r , 1978).  prominent peaks at 2900, 1460, 1390 and 700 cm"  Nujol  cm  1  mull used to mount the samples. 41  However,  a r e from the  two a d d i t i o n a l ,  Table 9. Sulphur enrichment of humic a c i d s by p o l y s u l p h i d e s i n alkaline solutions. HA e x t r a c t e d from: 1.sediment  mg C e x t r a c t e d  SS (mg)  1  S  S  n  2 r/  c  335  alone,  2.sediment spiked with  s  /  3  c  0.030+0.001  338  0.392  0.001  0.059+0.002  185  3.325  0.018  0.211+0.007  217  0.557  0.003  0.039+0.002  .„ o (4) 0.4% S . n  c  3.sediment spiked ,o (4) S  0.4%  and  with 1.5%  (4) Na S.9H o: 2  2  4.sediment spiked with (4) 1.5% Na S.9H 0: 2  2  1.Amount of elemental sulphur produced by a c i d p o l y s u l p h i d e s d u r i n g humic a c i d p r e c i p i t a t i o n . 2.SS  n  normalized  t o carbon e x t r a c t e d  42  of  (HA + FA),  3.S/C ratio of humic a c i d s after decomposition of the p o l y s u l p h i d e s ) . 4.% dry weight sediment.  hydrolysis  acidification  (and  Fig.  3:  I n f r a r e d s p e c t r a of humic a c i d s e x t r a c t e d : ( a ) from a marine sediment deposited under oxic conditions (S/C of e x t r a c t e d HA: 0.030+0.007). (b) from the same sediment spiked with Na S a n d elemental sulphur (S/C of the e x t r a c t e d HA: 0.211+0.001). 2  43  well-defined  peaks appeared  e x t r a c t e d i n the presence peak  at  1260  thiocarbonyl cm  1  cm  in the spectrum  to  ( S i l v e r s t e i n et a l . ,  this  f o r the S-H  the  absorption  1981),  i s t e n t a t i v e l y a s c r i b e d to a C-S  no evidence  humic  acids  of p o l y s u l p h i d e s ( F i g . 3 , curve b ) . The  corresponds  1  of the  band  of  while the peak at  s t r e t c h i n g band.  s t r e t c h i n g band near 2600 cm  band i s known to be very weak and may  1  800  There  .  was  However,  not be d e t e c t a b l e  in  t h i s complex matrix. An attempt produced  checked  acidified  drive  after  decomposition  was  the amount of p o l y s u l p h i d e s  a l k a l i n e humic a c i d of elemental  solutions  sulphur and  then  while being under a vigorous n i t r o g e n stream Any  acidification  elemental sulphur found was  assumed  of the p o l y s u l p h i d e s present  to  come  to  in  the  from  the  i n the humic e x t r a c t s .  amount of p o l y s u l p h i d e S a s s o c i a t e d with the humic  extracts  then expressed as the r a t i o of elemental sulphur e x t r a c t e d by  benzene carbon  from (DOC)  the a c i d i f i e d e x t r a c t s to  higher  polysulphide  treatments,  #3 produced S  dissolved  organic  ( S S / C ) . Table 9 n  humic a c i d s with a s i g n i f i c a n t l y  to carbon  ratio  (SS /C) than  the  n  other  c o n f i r m i n g the c o n c l u s i o n s drawn e a r l i e r . Part of the  e x t r a c t s from treatments acidification,  atmosphere.  the  of the e x t r a c t before a c i d i f i c a t i o n  shows that treatment  to  The  f o r the presence  the excess H 2 S .  off  extracts  The  made to determine  i n these r e a c t i o n s .  were f i r s t were  was  #3 and  against  #4  (Table 9) were d i a l y s e d ,  d i s t i l l e d water,  under  E s s e n t i a l l y a l l the p o l y s u l p h i d e s passed 44  a  prior  nitrogen  through  the  membrane  (Table 10),  associated present HS ) rapid  as  low molecular  between  supported  dialysis.  The  by  10,  LMwt SS )  (Table  10,  expected).  before  acidification,  not  I conclude  that  n  polysulphides decrease  and in  was  chemically they  organic  i n the  this  or decomposition.  sulphur  during  dialysed  was  formed  to  their  i t must be a r e s u l t  of  during d i a l y s i s .  CONCLUSIONS  It has been shown that c e r t a i n p r e c a u t i o n s are necessary order  extract  the humic a c i d  sediments  without  artificially  Elemental  sulphur  and  to  fraction raising  from its  anoxic  sulphur  free s u l p h i d e s must be removed  extent  of  sulphur  g r e i g i t e must be Although found  contamination  from c o - e x t r a c t e d  in  marine content.  from  sample before proceeding with the a l k a l i n e e x t r a c t i o n .  was  is  dialysates  decrease c o u l d not be due Therefore,  The  matter  polysulphides  no elemental  (HS^,  matter.  much s m a l l e r than the amount  Since  were  polysulphides  of p o l y s u l p h i d e s found  t h e i r r e a c t i o n with organic matter  2.2.4  were  weight i n o r g a n i c  the  amount  (Table  oxidation  they  were r e a c t i n g r a p i d l y with the o r g a n i c  reaction  further  that  with the organic m a t r i x .  which  4  showing  the  A l s o , the pyrite  and  estimated.  these requirements convenient  to  can be met  freeze-dry  45  in various  the  sediment  ways,  it  samples  Table  10. D i a l y s i s of p o l y s u l p h i d e s present i n humic e x t r a c t s .  HA e x t r a c t e d from:  mgC dialysed  HMwt SSn(mg)  LMwt SSn(mg)  expected (mg)  Sedt. s p i k e d with S and Na S.  134.6  0.002  1.60  2.40  Sedt. s p i k e d with Na S.  140.4  0.003  0.12  0.36  2  2  1. Elemental sulphur recovered upon a c i d i f i c a t i o n of the humic acid solution after d i a l y s i s . 2. Elemental sulphur recovered upon a c i d i f i c a t i o n of the dialysate. 3. Amount of elemental sulphur expected i f the amount of p o l y s u l p h i d e s had stayed constant during d i a l y s i s ( i . e . = mgC d i a l y s e d (Table 10) x SS /C ( T a b l e 9 ) ) . n  46  immediately  a f t e r t h e i r e x t r u s i o n under a n i t r o g e n atmosphere, on  board  ship.  The  humic substances  were e x t r a c t e d by  after  removal of the elemental sulphur from the  with benzene. The humic a c i d s were p r e c i p i t a t e d s o l u t i o n s by a c i d i f i c a t i o n to pH2 the  formation  produced  by  of the  elemental  decomposition  of  a  produced  determined.  f r e s h l y prepared C r C l was  This  procedure  sedimentary  2  humic  HS 2  the of  elemental  the samples were t r e a t e d  s o l u t i o n and the  amount  of  sulphur c o n t r i b u t i o n  HS 2  of  greigite.  is  thought  values  for  a c i d s c l o s e to t h e i r true ijn s i t u values  and  i n anoxic sediments.  t h i s e x t r a c t i o n procedure  EVOLUTION  of  A.V.S.,  to  yield  sulphur  used to study the d i a g e n e t i c changes i n the organic  fraction  2.3  oxidation  minimize  done under a vigorous stream  measured to estimate the  c o - e x t r a c t e d p y r i t e and  was  from the a l k a l i n e  co-extracted  Subsequently,  0.5N  sediment  The p r e c i p i t a t e s were f r e e z e - d r i e d and t h e i r  composition with  dried  In order to  sulphur by the  p r e c i p i t a t i o n of humic a c i d s was nitrogen.  with HC1.  NaOH  OF THE  A more d e t a i l e d  sulphur  presentation  of  i s given i n s e c t i o n 2.3.2.2.  SULPHUR CONTENT OF THE  HUMIC  FRACTION  OF  MARINE SEDIMENTS DURING EARLY DIAGENESIS. 2.3.1  INTRODUCTION. The  extracted  e v o l u t i o n of the sulphur content of the humic from  a  nearshore  sediment 47  core  was  substances  investigated.  S p e c i a l a t t e n t i o n was humic  materials  according details  2.3.2  to  taken to a v o i d sulphur contamination  during  the  the  which  was  in  more  i n s e c t i o n 2.3.2.2..  MATERIALS AND  Sediment  METHODS.  samples  (Fig.  SAMPLING PROCEDURE.  were c o l l e c t e d  coast of B r i t i s h Columbia.  from J e r v i s I n l e t on  Its  a l l o w i n g deep water  sediments are d e p o s i t e d under  well-oxygenated  c o n d i t i o n s and support a v a r i e t y of macro-benthic c o n t a i n on average (10-13)  3-4%  organic carbon  organisms.  They  with a r e l a t i v e l y high  suggesting some t e r r e s t i a l  wooded f l a n k s on both s i d e s of the i n l e t .  input from  the  Three cores were taken  (JV11, 49°53.9'N, 123°54.1'W. F i g . 4)  a  were c o l l e c t e d with a l i g h t w e i g h t  Two  c o r e r d e s c r i b e d by Pedersen used  for  isotope  chemical analysis.  et a l .  analyses and A t h i r d core  (1985)." One  the other  C/N  steep  from the same l o c a t i o n depth of 650m.  the  I t i s a t y p i c a l long, narrow and deep  4) with a r e l a t i v e l y deep s i l l ,  ventilation.  ratio  performed  method o u t l i n e d above and presented  2.3.2.1 SITE DESCRIPTION AND  fjord  extraction  of the  core  (core B)  (core C) was  gravity  (core A) for  taken with  from  was  stable a  box-  c o r e r f o r bulk sediment a n a l y s i s . Settling interceptor  particulates  were  also  t r a p deployed at JV11.5 (660m  48  collected deep,  using  Fig.  4),  an 60m  F i g . 4: Map  of J e r v i s  Inlet.  49  above  the  sea  September  floor,  18th,  cylinder  1985). an  The  a 6 week  period  (August  8th  to  a  PVC  c o l l e c t o r t r a p c o n s i s t e d of  height  of  48cm. B a f f l e g r i d s were placed at the opening of the c y l i n d e r  and  in the  with  over  i n t e r n a l diameter of  12.5  sampling chamber ( I s e k i et a l . ,  solution  (500ml) c o n t a i n i n g  2.3.2.2 EXTRACTION AND CORE  A:  The  0.5%  NaN^  were HS  5.  was  measured  2  sediment  (step  few  was  immediately  The  (step  used as a  immediately  frozen  freeze-dried  present.  (4)).  significant  Since  the  (Appendix I I ) .  (step ( 3 ) ) .  of  considered  complete.  elemental  sulphur  cyanolysis  (step  sulphur,  The  the  50  phase  acetone  and  dried  the  a l s o removed the  free  a known volume of benzene from the  this  benzene  (5)) a c c o r d i n g  blue  solid  i c e and  was  f r e e z e - d r i e d sediments  first  After centrifugation, in  subsamples  were measured  a second benzene e x t r a c t d i d not  amount  shown  methylene  T h i s procedure  t h e i r o x i d a t i o n , and  used to e x t r a c t elemental sulphur (step  to the diagram  for  pore waters were c o l l e c t e d and  (2)) using  Subsequently,  (i.e.  subsampling, the  with a mixture of dry  samples while a v o i d i n g sulphides  NaCl  preservative.  core  Sulphate c o n c e n t r a t i o n s  weeks l a t e r by gravimetry  quickly  A saturated  samples from t h i s  (1)).  procedure of C l i n e (1969). a  a  ANALYTICAL METHODS.  A f t e r core e x t r u s i o n and  centrifuged  and  1980).  chemical analyses) were processed a c c o r d i n g in F i g .  cm  extraction  was and  measured Skoog  any was  the c o n c e n t r a t i o n  extract  to B a r t l e t t  yield  of by  (1954)  samples extruded on board in N _ filled 2  glove_box  centrifuged (I) pore water sulphide  solid phase  * (2) analysis  freeze dried (3)  sulphate analysis  benzene 0-5N NaOH extr. (6)  I  humic  extract  benzene extr. (7)  D.O.C. anal  + HCI (8) (cont. N bubbling) 2  I  benzene extr. (9) centrifuged(ll)  elemental analysis  S° analysis (10)  HCI hydrolysis (12) sulphate  hydrolysed  analysis(l3)  H.A.  CrCI  I  2  reduction (14)  I  pyrite analysis  F i g . 5 : Humic e x t r a c t i o n procedure.  51  extr.  (4) S* analysis  (5)  (Appendix  I I ) . The benzene s t i l l  present  i n the sediment  c e n t r i f u g a t i o n was d i s p l a c e d by oxygen-free humic  substances  D.O.C.  with  as  were e x t r a c t e d with NaOH 0.5N  e x p l a i n e d i n Appendix I I .  the humic  extracts  elemental  sulphur  following  manner  solutions  were f i r s t  presence  of  Elemental the  d e i o n i z e d water. (step(6)).  of the humic e x t r a c t s was measured by the  method,  formed  were by  acid  (see a l s o Appendix I I ) .  by  e x t r a c t e d with benzene,  elemental sulphur before  e f f i c i e n c y of the sulphur e x t r a c t i o n  solutions  measuring in  alkaline  to check  the the humic  f o r the  acidification  sulphur was never d e t e c t e d a t t h i s  The  associated  hydrolysis The  The  dry-combustion  Polysulphides  determined  their  after  (step(7)).  stage,  confirming  i n step ( 4 ) .  The humic  were then a c i d i f i e d t o pH2 with HC1 (step (8)) over 12  hours under constant n i t r o g e n bubbling, t o a v o i d the formation of S°  by  the o x i d a t i o n of  (AVS).  These  benzene  (step  acidified (9)).  co-extracted e x t r a c t s were  The  acid-volatile then  sulphides  re-extracted  elemental sulphur measured  in  e x t r a c t s was assumed t o come from the a c i d h y d r o l y s i s of polysulphides normalized  (step  (10)).  t o the D.O.C.  These  polysulphides  with these  organic  were  then  of the a l k a l i n e humic s o l u t i o n .  After  benzene e x t r a c t i o n , the a c i d i f i e d humic e x t r a c t s were c e n t r i f u g e d (step  (11)) and the p r e c i p i t a t e d humic substances  f r e e z e - d r i e d f o r subsequent a n a l y s i s . (8)  were  contents  performed of  s t r i c t l y under  and  A l l o p e r a t i o n s up t o step nitrogen.  the humic m a t e r i a l were determined 52  recovered  The  C,  N,and  S  as d e s c r i b e d i n  Appendix also  I I . Sulphate e s t e r s ,  determined,  by  II).  titrimetrically  i n the humic a c i d s  measuring the sulphate produced  h y d r o l y s i s i n 5N HCl, (Appendix  present  at 120°C (King and Klug,  Sulphate  in  the  by  hydrolysate  was  measured  (Howarth, 1978) (step (13)). The h y d r o l y z e d humic  This core,  f o r isotope a n a l y s i s ,  e s s e n t i a l l y the same way,  after  were not c e n t r i f u g e d ( s t e p (1), addition  of  oxygen-free through  of  the s l u r r y f o r 48 hours and the  HS  o f f the sediment was c o l l e c t e d  water,  but i n s t e a d , stream  stripped  in a  a  2M  zinc  2  acetate  q u a n t i t a t i v e l y recovered H S from a pore 2  sample spiked with 1mM/l of d i s s o l v e d s u l p h i d e .  hours, water  F i g . 5),  deionized  was passed  s o l u t i o n . T h i s procedure  was processed i n  although with some m o d i f i c a t i o n s . The  nitrogen  water  sulphur  (Appendix I I ) .  CORE B:  samples  their  1980) ( s t e p (12))  a c i d s were f i n a l l y d r i e d , ground and analyzed f o r p y r i t i c (step(l4))  were  Within  4  a l l t r a c e s of H S disappeared even though the pH of the 2  had  Accordingly,  r i s e n from 8.5 to 9.7, a  due t o the s t r i p p i n g of  q u a n t i t a t i v e recovery from the sediment  must have been obtained and the i s o t o p i c composition sulphide aqueous  formed  must  sulphides.  reflect  The samples were  subsequently  2 >  samples  of the  the i s o t o p i c composition  C0  zinc  of the  freeze-dried  (step ( 3 ) , F i g . 5) and e x t r a c t e d with benzene ( s t e p (4), F i g . 5 ) . In  this  purified  case,  the  elemental  sulphur  was  not  by t h i n l a y e r chromatography on S i 0 , 9  53  measured,  with 30%  but  CH_C1  9  and  70% Hexane.  from sulphur, The  humic  T h i s treatment separated the o r g a n i c i m p u r i t i e s  which was  then e l u t e d with benzene and  substances were then e x t r a c t e d i n the same manner  for core A (step 6,8  The humic m a t e r i a l was prior  isotope  to  as  and .11, F i g . 5) but no attempts were made to  recover the sulphur formed  120°C  air-dried.  by the decomposition of p o l y s u l p h i d e s .  f i n a l l y t r e a t e d with 5N HC1  isotope a n a l y s i s .  a n a l y s i s are expressed  The  results  in the  f o r 5 hours at of  notation,  the  stable  using  Canon  D i a b l o T r o i l i t e as the standard. CORE C: Total  Bulk sediment  a n a l y s e s were performed  carbon was measured by dry combustion  on t h i s c o r e .  - gas chromatography  with a c o e f i c i e n t of v a r i a t i o n of 1.25%. Carbonates were analyzed on  a  C0  coulometer  2  precision  of 10%.  (Coulometrics Inc.  Organic carbon was  model  estimated  5010) by  a  difference.  T o t a l sulphur and manganese were measured on an automated X-ray  with  Philips  f l u o r e s c e n c e spectrometer u t i l i z i n g a Rh t a r g e t X-ray  tube  (Appendix I I ) . SEDIMENT material  available,  interceptor were  TRAP MATERIALS:  acidic  a m o d i f i e d procedure had to  t r a p c o l l e c t e d 2.1g  extracted  centrifugation, water  Because of the small q u a n t i t y  with  100ml  be  of d r i e d m a t e r i a l ,  NaOH  0.5N  the humic e x t r a c t was  under  room . temperature  s o l u t i o n obtained was  The  of which  2g  After  dialyzed against deionized The  slightly  evaporated i n vacuo,  and the d r i e d r e s i d u e r e d i s s o l v e d 54  used.  nitrogen.  f o r 4 days in order to remove NaOH and s a l t . colloidal  of  in  at  exactly  10ml  NaOH 0.5N.  remaining  solution  cellulose was  The D.O.C. was  of t h i s s o l u t i o n was  added  to  0.5g  of  and d r i e d under an i n f r a - r e d lamp.  weighted and homogenized and i t s sulphur  the F i s c h e r sulphur D u p l i c a t e analyses  analyzer  measured.  The  microcrystalline The d r i e d  content  (detection l i m i t :  mixture  measured on  20ppm) as b e f o r e .  were made and agreed to w i t h i n 2.5%.  2.3.3 RESULTS AND DISCUSSION.  The Table  r e s u l t s from the bulk  11  and  F i g . 6.  a n a l y s i s of core C are  The s u r f a c e of  c o n s i s t e d of a w e l l - d e f i n e d oxide indicative underlying showing carbon 25cm  intensive  anoxic  zone.  a significant decreased  the o x i c  deeper,  remobi1ization  part  with  within  enrichment i n the s u r f a c e sample. from 4.28% to 3.41% w i t h i n e s s e n t i a l l y constant  increased  suboxic  zones and  increased  the presence of anoxic  of the sediment.  1952) and  the top  i n the deeper  more  microniches  Such microenvironments  t o account f o r b a c t e r i a l  55  2  i.e.  gradually  This p r o f i l e  suggested t o e x p l a i n the occurrence of a u t h i g e n i c F e S Rittenberg,  the  Organic  r a p i d l y w i t h i n the top 15cm,  w i t h i n the s u l p h i d i c part of the c o r e .  consistent upper  and  analyzed  T h i s i s i n agreement with the Mn p r o f i l e  gradually  T o t a l sulphur  sediment  in  l a y e r (1 to 2 cm i n t h i c k n e s s ) ,  Fe and Mn  of the core and stayed  parts. in  of  the  shown  is  within  the  have  been  (Emery and  reduction  of  Table  11. Bulk sediment a n a l y s i s  Depth (cm)  £C%  0- 1 3- 6 7-10 11-14 1 5-18 23-26 27-30 35-38 39-42 43-46 47-50 51-54 55-58  4.43 4.23 4.15 4.15 3.95 3.46 3.63 3.80 3.71 3.88 3.68 3.85 3.79  r  9carb°  C  0.15 0.09 0.08 0.15 0.09 0.05 0.11 0.20 0.14 0.16 0.08 0.23 0.30  4.28 4.14 4.07 4.00 3.86 3.41 3.52 3.60 3.57 3.72 3.60 3.62 3.49  % org  56  (% dry w e i g h t ) .  S%  0.24 0.40 0.59 0.73 0.73 0.69 0.83 0.85 0.92 0.93 0.80 0.89 0.82  Mn%  3.02 0.83 0.49 0.84 0.76 0.53 1.18 1.10 0.88 0.41 0.74 1 .32 1 .04  Fig 6.: Bulk sediment analysis (data from core C ) .  57  r a d i o - l a b e l l e d sulphate  (Jorgensen,  1977)  i n the o x i d i z e d s u r f a c e  l a y e r s of marine sediments. Pore  water  surface  20cm  maximum  value  recovered  increase  was  2  and  o~ S 34  ~550  core  JJM  B  °/oo  (Fig.  i n the to  a  deeper i n the core isotope f r a c t i o n a t i o n  to the r a t e of sulphate lighter  below d e t e c t i o n l i m i t  HS 2  therefore,  formed  7).  The  zinc  acetate ~40cm,  ( F i g . 12).  I t has  reduction  (Harrison and  increase  in  the  /oo  and  reduction  conditions. The elemental  sulphides showed by  shown  a an  that  Thode, 1958).  The  core  may,  i s a pattern  1980)  of the pore water  of  sulphur  a  to  organic matter with depth.  Kaplan,  32 preferential  to  followed been  the  r e d u c t i o n r a t e , due  34  Goldhaber  cm  traps  deeper i n the upper p a r t of the  i n c r e a s e i n c T S ° / o o deeper i n the core (e.g.  in  i s generally inversely proportional  r e f l e c t a decrease i n sulphate  reported  45  dissolved  depth of  the d e p l e t i o n of r e a d i l y m e t a b o l i z a b l e The  (1juM)  i n c r e a s e d r a p i d l y between 30 and  of  from  decreasing  sulphur  HS  and  often  reflects  sulphate,  an  due  to  = SO^  ,  under  p r o f i l e showed a  above the s u l p h i d i c zone ( F i g .  8).  semi-closed broad  T h i s i s probably  system  peak, due  just  to  the  3+ upward  diffusion  the sub-oxic  of H S 2  and  zone, a c c o r d i n g  2 FeOOH + 3 HS~  i t s subsequent o x i d a t i o n by Fe to:  > 2 FeS  + S° + 3 OH~  A s i g n i f i c a n t amount of elemental the  top  in  2  sulphur was  l a y e r s of the sediment column, 58  + H0  (Berner,  1964)  a l s o found  even w i t h i n  the  in  oxide  H S 9  100  200  300  (MMLT ) 1  400  500  600  23  25  27  E o  UJ O  19  21  SOI (mML"') Fig.  7:  Distribution of pore water s u l p h i d e and c o n c e n t r a t i o n s (data from core A ) .  59  sulphate  F i g . 8: C o n c e n t r a t i o n p r o f i l e (data from core A) and i s o t o p e composition (data from core B) of elemental s u l p h u r .  60  surface water  layer,  far  gradient.  diffuses. mixing  elemental  due  w i t h i n the oxic and  sulphate  reduction  Alternatively,  due  this  to b i o t u r b a t i o n . sulphur  pore  2  T h i s i s probably  microenvironments dissimilatory  from the zone of i n f l u e n c e of the H S to the presence of sub-oxic  occurs  anoxic  zones,  in  from  which  and  which HS 2  c o u l d have a l s o been produced by Within  concentration  the  sulphidic  tended  to  zones,  decrease,  the  either  because of i t s r e d u c t i o n , c h e m i c a l l y and/or m i c r o b i o l o g i c a l l y , or its  incorporation into pyrite. The  stable  second core  isotope  composition  (core B) showed a very  of S° e x t r a c t e d  striking pattern.  the  very negative c ) S / o o values obtained  its  postulated  3 4  sulphate heavier  origin  reducers). at  abundant,  are  0  (i.e.  o x i d a t i o n of H S 2  However,  elemental  and  becomes  sediment column ( F i g .  l i g h t e r again 8).  In  produced  where  with  by  becomes it  the  general,  consistent  sulphur  the s u b o x i c / s u l p h i d i c boundary,  from  is  the much most  in the deeper p a r t of  I t i s very d i f f i c u l t  the  at t h i s stage  to  i n t e r p r e t the minimum i n the p r o f i l e . Chemosynthetic o x i d a t i o n of o 32 s u l p h i d e by a T h i o b a c i l l u s produces a S enriched in S by about 2.5°/oo (Kaplan  and Rittenberg,.  1964).  In the upper p a r t of  the 32  core  B,  elemental  compared to H S 2  found in the top activity nitrate  sulphur  (Table 15 cm  would s e e m ' s l i g h t l y e n r i c h e d  16).  as  S  I t i s t h e r e f o r e p o s s i b l e that the  of the core  of chemoautotrophs.  in  i s the r e s u l t of the  These  electron acceptors. 61  metabolic  b a c t e r i a r e q u i r e oxygen  It i s therefore  S°  expected  or that  their  influence  would  sediment column. when  T h i s e x p l a n a t i o n may seem somewhat  considering  compete  with  be r e s t r i c t e d to the upper p a r t  problematic  the l a r g e pool of FeOOH a v a i l a b l e  the b a c t e r i a l  oxidation.  However,  of the  which  HS 2  will  produced  3+ within  microenvironments  locally  s u i t a b l e e l e c t r o n acceptor microniches, Deeper  in  because are  d e p l e t e s the  Fe  .  If  some  d i f f u s e s toward the boundary of  these  chemoautotrophic o x i d a t i o n of H S would be p o s s i b l e . 2  the sediment,  t h i s type of o x i d a t i o n  is  of the lack of s u i t a b l e e l e c t r o n a c c e p t o r s  being brought  impossible  {unless  i n by b i o t u r b a t i o n ) and chemical  they  oxidation  by  3+ Fe  (e.g.  producing (1958)  Rickard,  S°.  the heavier large  a  3 4  o x i d a t i o n of H S by 0 2  of  H  2 ' S  concentration  gradient,  fractionation  reported  smaller  than  conditions decrease i n part  main  mechanism  that  sulphur  Rafter  produced  T h i s i s i n accordance  2 <  a t the s u b o x i c / s u l p h i d i c boundary diffusing  up  along  the  i s being o x i d i z e d by i r o n by  Kaplan and R a f t e r  reported  here 3+  of o x i d a t i o n ( 0 vs Fe 2  ) were  very  sulphur  pore  with where  water  oxides.  (3°/oo)  (~15°/OO);  /oo of the elemental  The  i s much  however,  the  different.  The  found i n the deeper  of the s u l p h i d i c zone c o u l d r e f l e c t a gradual  between S° and d i s s o l v e d s u l p h i d e s . these  the  S enrichment i n elemental  S° recovered  amounts  i s probably  I t i s i n t e r e s t i n g to note t h a t Kaplan and  reported  during a b i o t i c  1974)  equilibration  I s o t o p i c e q u i l i b r i u m between  s p e c i e s would produce elemental 62  sulphur  slightly  enriched  in  S (Ohmoto and Rye,  h o r i z o n of core B.  Equilibria  reported to be r a p i d and Since the  elemental  sulphur  that  found  the  in  continuously higher  would  being  reversible  peak  formed  to produce p y r i t e  result  has  1973)  of  (e.g.  elemental  not r e s i d u a l  Berner,  of  but  chemical S°/oo  with  reflect  Explanations speculative  designed The  was  S° r e a c t s  with  (Sweeney  held  in  clay  its  lattices  1971;  HS 2  decrease the  by Fe  .  The  be confirmed.  is  a  The  possible  The  I f so,  profile  heavy  gradual  the  of  S° S°  S°  upon  decrease  dissolved  i n turnover r a t e of  isotope  at t h i s stage.  formation.  van Breemen, 1980). T h i s would be  formation of i s o t o p i c a l l y 3+ of  of S° must be a  f o r the formation of S° w i t h i n  values at e q u i l i b r i u m with  for  which  been r e p o r t e d d u r i n g t h i s r e a c t i o n  the  a  was  rate  the heavy i s o t o p i c composition  oxidation  rather  isotopic  Fe(lII)  toward  to  1972).  sulphur  Since no  s u l p h i d i c zone (Drever, consistent  below  suboxic/sulphidic  and consumed at a  mechanism which c o u l d account  need  the  d i s c r i m i n a t i o n o c c u r r i n g during  reduction  could  at  seem to i n d i c a t e that  produced  cm  (e.g. Boulegue et a l . , 1982).  than the rate of i s o t o p i c e q u i l i b r a t i o n .  and Kaplan,  3 4  i n the 60-66  i n the l^S-Sg-H^O system have been  s u l p h i d i c zone was  discrimination  0  such as observed  i s o t o p i c e q u i l i b r i u m seems to be achieved only 30cm  boundary,  FeS  1979)  sulphides  with can  depth.  only  general f e a t u r e s of t h i s l a b o r a t o r y experiments  of  be  profile  could  be  to shed l i g h t on the v a r i o u s processes i n v o l v e d . humic  acids  extracted 63  from t h i s  sediment  showed  a  continuous Table  increase  14).  The  (Table  12) and  higher  but  i n t h e i r S/C  r a t i o s obtained  still  planktonic materials top  20cm  from the  from the upper 2cm  were  r a t i o s with  settling  of the core  very c l o s e to the  (Table  values  i.e.  in the  reported.  (particularly  macrophyte  species  been reported to c o n t a i n more sulphur 1963);  however,  the i n f l u e n c e of any  not p a r t i c u l a r l y h i g h  mud  (Table  S/C  diagenetically-induced  i n sulphur  increase  increase  processes,  in  preferential here  with  reflect elements process.  a  the  S/C  red  algae)  than plankton  (Kaplan  Also,  the  bacterial  i n the humic  r a t i o of  S  relative  fraction anoxic  in  occurring organic  humic  of  fraction,  A l t e r n a t i v e l y , sulphur  64  C  in  the  result  simultaneously.  matter  of C over S.  the r a t e  to  i n c r e a s e c o u l d be the  can  Since we  only a f r a c t i o n of the organic matter,  into  f a r from  even in i s o l a t e s from  in  possibly  mineralization  variation  values  p r o f i l e r e p o r t e d must t h e r e f o r e r e f l e c t a  sedimentary humic m a t e r i a l s . Such an several  the  reached  planktonic  i n t e r t i d a l zone.  in part incorporated  is  of  for  zone,  and  the sediment s t u d i e d here was  extensive  biomass which w i l l be  13). The  seemed  sub-oxic  than any  et a l . ,  14)  reported  values which were s i g n i f i c a n t l y higher Some  9,  particulates  s t a r t e d to accumulate i n the pore waters,  2  have  (Fig.  (Table 2). They i n c r e a s e d r a p i d l y w i t h i n  of the sediment column,  before H S  depth  incorporation during  the  occur  are it  An by  dealing may  also  of  these  humification  a d d i t i o n to the humic substances  S/C 0-02  Fig.  9:  0 03  0-04  005  S/C r a t i o s by weight of humic a c i d s e x t r a c t e d from core A: S/C = total sulphur content of HA normalized t o C; S /C = C-bonded sulphur of HA normalized t o C.  65  Table 12. Amount of C and S e x t r a c t e d by NaOH 0.5N from settling particulate materials (org C% = 5.14%) c o l l e c t e d from an interceptor t r a p deployed i n J e r v i s I n l e t ( S t a t i o n JV 11.5).  % dry weight  C S S/C  1.17+  particulates  0.025  0.032 + 0.0015 0.027 + 0.001  66  Table  13. M i c r o b i a l S/C  ratios.  g  Organism  S/C  Bacteria  0.013  Spector  Bacter i a  0.010  Bowen (1979)  Fresh water Sea water  isolates  1  .2 isolates'  ng S/10  0.007-0.012  References  (1956)  74-421  Jordan and Peterson (1978) Cuhel et a l . (1981)  1 25  Cuhel et a l . (1982)  0.004-0.010  D e s u l f o v i b r i o s a l e x i g e n s <0.019 Fermentive b a c t e r i a . from anoxic sediments  cells  Cuhel et a l . (1982)  <0.017  1 - Chromobacterium 1ividum, unidentified isolates  Pseudomonas  2 - Pseudomonas halodurans and Alteromonas  fluorescens  and  luteo-violaceous  3 - S wt% i n b a c t e r i a l p r o t e i n s = 1.00%. T h i s corresponds to a S/C i n average p r o t e i n s = 0.019. Since more than 90% of bacterial sulphur were r e p o r t e d to be a s s o c i a t e d with proteins, the S/C ratio of the whole organism must be c o n s i d e r a b l y l e s s than 0.019. 4 - Same reasoning as above with a S wt% 0.92%.  67  in b a c t e r i a l protein  =  Table  14.  total  sulphur,  S  ), S  C and S c o n t e n t  o f humic a c i d s e x t r a c t e d from c o r e A. S  Spy = p y r i t i c  = C-bonded s u l p h u r  c  1  sulphur,  (i.e. S - S  % wt humic Depth (cm)  C  S. 1  S„ p  S  S = organic  S  + 6  +  6  ), S  + 6  sulphur  (i.e. S  fc  =  t  -  = sulphate e s t e r s .  acids S  C  S/C  S  + 6  /C  S /C C  y  Surf.  49. 9  1 .52  0. 03  1 .49  0. 35  1 .14  0. 030+0. 0008  0. 007  0. 023  0- 2  49. 7  1 .55  0. 03  1 .52  0. 38  1 .14  0. 031+0. 0009  0. 008  0. 023  2- 6  43. 6  1 .43  0. 04  1 .39  0. 36  1 .03  0. 032+0. 0009  0. 008  0. 024  18-22  46. 0  2 .19  0. 27  1 .92  0. 46  1 .46  0. 042+0. 0014  0. 010  0. 032  22-26  35. 4  1 .62  0. 18  1 .44  0. 46  0 .98  0. 041+0. 0012  0. 013  0. 028  28-32  39. 9  2 .02  0. 18  1 .84  0. 48  1 .36  0. 046+0. 0014  0. 012  0. 034  32-36  41 . 0  2 .05  0. 20  1 .85  0. 48  1 .37  0. 045+0. 001 4  0. 012  0. 033  44-48  31 . 5  1 .57  0. 13  1 .44  0. 32  1 .12  0. 046+0. 0014  0. 010  0. 036  56-60  35. 3  2 .00  0. 15  1 .85  0. 46  1 .39  0. 052+0. 0016  0. 013  0. 039  68-72  38. 2  2 .02  0. 24  1 .77  0. 36  1 .41  0. 046+0. 001 5  0. 009  0. 037  1 S r e f e r s t o o r g a n i c sulphur which does not produce during HC1 h y d r o l y s i s ( i . e . a l l o r g a n i c s u l p h u r but the esters). 2  -  Not c o r r e c t e d f o r a s h .  68  sulphate sulphate  c o u l d a l s o be brought about by chemical matter  and  inorganic  diagenesis. was  The  reduced  relative  r e a c t i o n s between organic  sulphur  species  during  importance of these v a r i o u s  i n v e s t i g a t e d f u r t h e r by studying the chemical  sulphur and into  the  by s t a b l e isotope a n a l y s i s . humic  polysulphides  matrix  would  sulphur with a l i g h t Organic  by  reaction  polysulphides  with  form of organic  H  sulphur  2^'  and/or reduced  organic  composition. were  found  associated  e x t r a c t e d humics. A w e l l - d e f i n e d peak occurs where I^S  processes  I n c o r p o r a t i o n of  l i k e l y produce a C-bonded isotopic  early  with  the  j u s t above the depth  s t a r t s to accumulate i n the pore water ( F i g .  11), i . e .  in the region where i n o r g a n i c p o l y s u l p h i d e s are more l i k e l y to be formed in abundance as an Gupta,  1973).  matter,  via  intermediate of H S 2  o x i d a t i o n (Chen  These p o l y s u l p h i d e s c o u l d then free  p o l y s u l p h i d e s and  radical  reactions,  t h i o l groups.  r e a c t with  and  Organic  organic  produce  organic  polysulphides could also  be formed by r e a c t i o n between n u c l e o p h i l i c groups of humic (e.g. t h i o l s , amines...) and S° in  the  sulphidic  decreases they  zone,  substantially,  (see r e a c t i o n s (5) and  the amount probably  due  and  of  organic  to t h e i r  acids  ( 6 ) ) . Once  polysulphides reduction,  as  are known to be unstable under s t r o n g l y reducing c o n d i t i o n s  (Boulegue, The  1982).  r a t i o of sulphate e s t e r s to carbon (S ^/C) i n the +  fraction  seemed  and  stayed roughly constant  then  to i n c r e a s e with depth w i t h i n the suboxic  69  (Table 14).  From the  S/C  humic zone and  70  SSn  Fig.  11:  /C  Polysulphides (SSn) a s s o c i a t e d with the humic extracts obtained from core A. The r e s u l t s are expressed i n weight r a t i o of elemental sulphur produced by t h e i r a c i d h y d r o l y s i s t o carbon.  71  S  /C  ratios,  the  r a t i o of C-bonded organic sulphur t o  (S /C) can be estimated  ( F i g . 9; Table  c  a  continuous  the  i n c r e a s e with depth.  carbon  14). T h i s r a t i o a l s o  shows  T h i s i s f u r t h e r confirmed  by  S/C r a t i o of the humic r e s i d u e l e f t a f t e r h y d r o l y s i s of  sulphate  e s t e r s and amino-acids  Therefore,  there  ( S / C ^) ( F i g . 10,  Table  n  i s an a d d i t i o n of  the  non-hydrolyzable,  15).  C-bonded  sulphur t o the organic matrix d u r i n g e a r l y d i a g e n e s i s . In  an  humification organic  attempt rate"  sulphur  differential  to  distinguish  ( i . e . difference and  carbon  mineralization  into  between  "differential  i n r a t e of i n c o r p o r a t i o n of the  humic  fraction)  r a t e and S a d d i t i o n  to  matrix  by chemical r e a c t i o n with i n o r g a n i c reduced  stable  isotopic  determined light  (Fig.  composition 12; Table  of  hydrolyzed  the  humic  species,  the  acids  was  humic  16). T h i s organic sulphur was of very  i s o t o p i c composition, which would support the importance  the chemical a d d i t i o n of sulphur to the organic m a t r i x . a  or  number  of  c o n s i d e r a t i o n s must be taken  into  of  However,  account  before  r e a c h i n g such a c o n c l u s i o n . An i s o t o p e mass balance can be estimated, ratios 16).  (Fig. If  reached is  due  isotopic  we  10,  Table  3 4  of HA  (Fig.  12,  Table  assume t h a t the sulphur system i n the sediment  steady-state, to  15) and c T s ° / o o  SA-ftyd  u s i n g the  that most of the chemical sulphur  n u c l e o p h i l i c a d d i t i o n of HS  and t h a t  f r a c t i o n a t i o n during t h i s reaction,  72  then:  there  has  addition is  no  Table  15.  C  and S content of  acids  extracted  from  core  A  humic after  h y d r o l y s i s i n 5N HCl, 120°C, 5 h r s .  % wt humic a c i d s Depth (cm)  s  C  2 S  / hyd C  Surf.  56 .8  1 .29  0 .023+0.0006  0- 2  59 .4  1 .60  0 .027+0.0008  2- 6  51 .7  1 .43  0 .028+0.0008  18-22  54 .5  1 .99  0 .037+0.0012  22-26  39 .8  1 .40  0 .035+0.0010  28-32  47 .3  1 .96  0 .041+0.0012  32-36  47 .4  1 .95  0 .041+0.0013  44-48  34 .0  1 .48  0 .043+0.0013  56-60  39 .5  1 .98  0 .050+0.0015  68-72  43 .2  2. 18  0 .050+0.0016  1 - Not c o r r e c t e d 2 - Corrected  73  f o r ash.  for p y r i t i c  sulphur.  Fig.  12:  Isotope composition o f f r e e s u l p h i d e s (H S) and h y d r o l y z e d humic a c i d s (HA) ( d a t a from c o r e B ) . 2  74  Table of  16.  Sulphur  isotope composition  free s u l p h i d e s ,  elemental  sulphur  and hydrolyzed humic a c i d s .  S> Depth (cm)  3 4  s°/  H.S  S°  0- 6  -  -22.3  -17.4  6-12  -  -27.6  -26.2  12-18  -27.3  -29.6  -25.6  18-24  -  -24.8  -26. 1  24-30  -32.4  -17.7  -29.7  30-36  -33. 1  -15.0  -28.7  36-42  -33.8  -15.8  -30.6  42-48  -31.6  -17.7  -29. 1  48-54  -32.3  -26.4  -29.4  54-60  -27.9  -23.8  -28.9  60-66  -27. 1  -31.5  -27.9  75  Hydrolyzed humic a c i d s  5  [ S / C  1  +  hyd i i ]  ls/C  1  [HS/C].  at  h  ^/C^  y  i  d  y  +  [HS/C]  +  d  J  i  - S.  1  §HS  i + 1  i +  ^  (  i + 1  ) (2)  1 + 1  - JHS  1  i + 1  LHS/Cj  +  (X.  1  i s the S / C  1  r a t i o of h y d r o l y z e d humic  aci< :ds  depth i ; (!) ^ i s the s t a b l e i s o t o p e r a t i o of h y d r o l y z e d  humic  a c i d s at depth i ; 0 ^  i s the s t a b l e isotope r a t i o of  + 1  humic free  h  [s/c,,].  =  +1  $  where  S  a c i d s at depth i+1; HS 2  at depth i+1;  ^ HS^  [HS/C]  If observed  the  observed  i s the amount of HS~  i + 1  to C, at depth  a d d i t i o n accounts  for  the  present sediment  to  i+1.  sulphur  = [S/C  i + 1  [HS/C]^  ]  i + 1  - [S/C  < A [ S/C^yjj] i +! t  + 1  must  h y d  be due  h y d  ]. =A[S/C  enrichment  [HS/C] in  1  (3)  i + 1  enrichment  > A t / hyd-'i + 1 c  '  s  o  m  e  s  u  l  rate"  or  carbon. P  the organic matter or i n c o r p o r a t e d  column,  ]  to a " d i f f e r e n t i a l h u m i f i c a t i o n  s  i+  h y d  p a r t of the sulphur  d i f f e r e n t i a l m i n e r a l i z a t i o n r a t e of sulphur and If  added  then:  [HS/C] If  HS  i s the s t a b l e i s o t o p e r a t i o of  +1  the hydrolyzed humic , normalized  hydrolyzed  must have been r e p l a c e d by HS  h  u  r  r  initially  higher  in  the  from depth  i+1,  In order to apply t h i s scheme to the present s i t u a t i o n ,  the  i . e . some i s o t o p i c exchange must have occurred.'  data were c l u s t e r e d i n t o three groups ( F i g . results  show that the amount of HS  account  f o r i t s i s o t o p i c composition  17).  The  added to the humic matrix is significantly  the i n c r e a s e in sulphur a c t u a l l y recorded. 76  12, Table  larger  These r e s u l t s can  to  than be  interpreted to  the  ways: e i t h e r the c T  i n two  organic matrix  3 4  S /oo of the sulphur added  is quite different  from that of  HS  some i s o t o p i c exchange occurs at each depth. Besides HS other  inorganic  organic  matter  sulphur s p e c i e s s u s c e p t i b l e are  elemental  Casagrande and Ng,  1979).  mid-depth  core,  in  the  sulphur and  Elemental and  to  ,  or  , the  two  reacting  polysulphides  (e.g.  sulphur i s much heavier  this  is  not  reflected  in  h y d r o l y z e d humic a c i d s . I t seems t h e r e f o r e that elemental has very l i t t l e  effect  with  at the  sulphur  i n e n r i c h i n g the humic m a t e r i a l s , at l e a s t  i n f u n c t i o n a l groups which can r e s i s t a c i d h y d r o l y s i s . T h i s i s in agreement very  with the work of Mango (1983) who  efficient  producing sulphur  been  reductively  totally  isotope measured,  composition but  it  the  + 1  .  -Tj,,  '  .  The  to account  [s/cl  -it [HS/C]  where  [HS/C]  g i v e s <^~ S°/oo 34  mid-  elemental  conditions. has or  of  The not an  isotopic  composition  f o r the A  f / hyd-'i + i s  C  observed can be computed by r e a r r a n g i n g Eq. ( 2 ) .  $ 1  while  i s l i k e l y to be c l o s e to HS  the added sulphur necessary  and cT^  same  carbohydrates,  of i n o r g a n i c p o l y s u l p h i d e s  i n t e r m e d i a t e value between S° and HS of  compounds,  i n a c t i v e under  was  2  dehydrating  a v a r i e t y of organosulphur was  stable  at  showed that H S  depth  i + 1  of -50  (24-54 cm)  i +  [  S  /c  and -24  Y  d  ]  i  ,  i s taken as equal + 8 °/oo  h  to A  [S/C  h y d  f o r the sulphur to be  ]  i + 1  .  added  This at  + 7°/oo f o r the deeper p a r t of the 77  Table  Depth 6-24  17. Isotope mass balance  <f. -26  *HS.  S/C  h y d  (see t e x t  .  ?  3.5X10"  2  for explanations).  HS/  A S/C  Ci  24-54  -29.5  -33  4.1X10~  2  (3.5+0.8)10"  54-66  -28.5  -27.5  5.0X10~  2  (4.1+3.0)10  78  h y d  .  2  »  0.6xl0  _2  »  0.9xl0~  _ 2  2  core  (54-66 cm).  sulphur  source.  exchange in  nor p o l y s u l p h i d e s seem an  I t appears l i k e l y  t h e r e f o r e that some  isotopic  core. by  T h i s i s o t o p i c exchange c o u l d p o s s i b l y bacterial activity.  anabolic  sulphur  requirement  Roy and T r u d i n g e r ,  produced  has an i s o t o p i c composition  some b a c t e r i a (e.g.  sulphate  and w i l l  synthesis sulphate  1970).  can  meet  sulphur  very c l o s e to the  sulphate  and R i t t e n b e r g , 1964).  methanogens)  are unable  t o reduce  instead a s s i m i l a t e sulphide for t h e i r  (Truper,  1982).  Also,  s u l p h i d e can t o t a l l y  uptake while a l l o w i n g optimal growth (e.g.  1955). Since sulphate a s s i m i l a t i o n  This  i s o t o p i c composition 90%  1955; are  and  Cuhel very  sulphur  low  weight molecules  (Roberts  an  f o r by et  al.,  et a l . , 1981, 1982). Since both c l a s s e s of compounds  labile, which  i t can be argued that a  pool  has been s y n t h e t i z e d at depth i  of  will  bacterial likely  be  and r e p l a c e d at depth i+1 by a newly-  biomass with an i s o t o p i c  H S of the corresponding 2  sulphide  More than  i n b a c t e r i a can be accounted  molecular  et  r e q u i r e s more energy, i t  s i m i l a r to the s u l p h i d e u t i l i z e d .  p r e f e r e n t i a l l y mineralized formed  suppress  w i l l produce a b a c t e r i a l biomass with  of the sulphur present  proteins  protein  Roberts  seems that many b a c t e r i a w i l l p r e f e r e n t i a l l y a s s i m i l a t e available.  sulphate  The organic  (Kaplan et a l . , 1963; Kaplan  However,  been  via assimilatory  (e.g.  being reduced  have  Most microorganisms  reduction  when  depth  2  mediated  al.,  adequate  between H S and organic sulphur occurred at each  the  their  Neither S  depth , 79  s i g n a t u r e s i m i l a r to that of the producing  an apparent  isotopic  exchange present  between organic sulphur and context,  matter analyzed refractory  sulphide.  However,  t h i s e x p l a n a t i o n seems u n l i k e l y .  The  organic  (hydrolyzed humic a c i d s ) must have been of a very  nature and  i t would be d i f f i c u l t  to v a l i d a t e a  turnover r a t e of m i c r o b i a l l y - d e r i v e d m a t e r i a l s i n t h i s  2.3.4  i n the  rapid  fraction.  CONCLUSIONS.  Accumulation  of organic sulphur  i n t o sedimentary  humic a c i d s  does occur during e a r l y d i a g e n e s i s . T h i s i s shown by the i n c r e a s e in  t h e i r S/C  avoid  r a t i o s with depth,  S contamination  been taken. indicates  The  even though a l l p r e c a u t i o n s  during sample h a n d l i n g and e x t r a c t i o n have  light  i s o t o p i c composition  that reduced  i n o r g a n i c sulphur,  of t h i s humic species,  d i s s i m i l a t o r y sulphate r e d u c t i o n are i n v o l v e d . of  isotopic  exchange,  nature of the i n i t i a l this  source of s u l p h u r .  found we  therefore,  part  of  the  by  because the  still  speculative  and  possibilities.  Vandenbroucke et a l . ,  matter  1985). I f  r a t i o s measured i n humic a c i d s ( i . e . that  humic substances  p r e c i p i t a t e s at low pH)  However,  c o n s t i t u t e the bulk of the organic  i n marine sediments (e.g.  assume that the S/C  produced  The a c t u a l mechanism of  chemical data must be used to c o n s t r a i n the substances  sulphur  these data cannot be used to r e v e a l  sulphur enrichment i s ,  Humic  to  which i s  r e f l e c t the S/C  80  extractable  and  which  r a t i o s of humic m a t e r i a l s  as a whole, i t would seem d i f f i c u l t S/C  r a t i o i s due  sulphur ratio  to the accumulation  residue would  to argue that the i n c r e a s e i n of non-biodegradable organic  in the organic m a t r i x .  A d o u b l i n g of  r e q u i r e the m i n e r a l i z a t i o n -of at l e a s t  organic carbon found  in the upper cm  of the core,  the  S/C  of  the  50%  w i t h i n the  50cm of the sediment column. T h i s i s not r e f l e c t e d i n the carbon p r o f i l e  (Fig.  6,  Table  11).  Moreover,  sulphur  top  organic found i n  organisms i s g e n e r a l l y a s s o c i a t e d with the most l a b i l e c l a s s e s of compounds,  mainly  proteins  metabolites  (e.g.  aminoacids,  are a l s o found 1973; the  and  low  molecular  weight  coenzymes, v i t a m i n s ) . S u l p h o l i p i d s  in p h o t o t r o p h i c  organisms (e.g.  Busby and  Cuhel and Waterbury, 1984). L a b i l e p r o t e i n s and most  readily  deposited 1985).  under  metabolized  components  is  f r a c t i o n s of the  oxygenated c o n d i t i o n s  Therefore,  the  accumulation  very u n l i k e l y .  sulphur  which i s found  esters.  They  occur  The  lipids  (Khripounoff  of t h e i r  Benson,  organic  matter  and  only other c l a s s  Rowe,  of  the  organic sulphate-  as sulphate p o l y s a c c h a r i d e s and  important  1975).  They  seem  to accumulate i n the humic m a t e r i a l s w i t h i n the upper  20cm  the sediment column (Table 14).  alone part  cannot e x p l a i n the S/C of  reduced, The  the sulphur  Siegel,  can  serve  of  s t r u c t u r a l f u n c t i o n s (e.g.  are  sulphur-containing  in s i g n i f i c a n t amount are  mainly  soluble  However,  p r o f i l e observed,  increment seems to be  this  s i n c e the  in the form  carbon-bonded groups which a l s o r e s i s t a c i d  accumulation  accumulation  of  more  hydolysis.  of b a c t e r i a l l y - d e r i v e d organic sulphur 81  major  is  also  unlikely, humic  s i n c e i t mainly c o n s i s t s of p r o t e i n s .  sulphur  result  of  during  an  a d d i t i o n of sulphur to the  .humification. sulphur  e a r l y d i a g e n e s i s must  Considering  species  and  abundance  humic  in  increase in  therefore  the r e a c t i v i t y of  their  The  be  matrix  reduced  the  during  inorganic  sediments,  chemical  a d d i t i o n seems the more l i k e l y mechanism. The  significant  sulphur enrichment  points  to  the  which occurs above  sulphidic  zone  relative  importance  boundaries  i n the process of sulphur enrichment.  Such  the  of  redox  boundaries  are found j u s t above the s u l p h i d i c zone of the sediment column or at  the  interface  B i o t u r b a t i o n , by of  different  of microniches  i n oxic  and  suboxic  layers.  i n c r e a s i n g the c o n t a c t between sedimentary  redox regime w i l l  zones  l i k e l y enhance the importance  of  such p r o c e s s e s . HS  diffuses  2  along i t s pore water c o n c e n t r a t i o n  from the s u l p h i d i c to the suboxic zone where i t i s has  also  been  shown  measurable  rate  presumably  by  in  oxidized  polysulphides, process  of  The  H„S  produce since  is  being  sediments  reducers,  residence  i s very s h o r t . to  sulphate  suboxic  sulphate  microenvironments. microniches  that  oxidized. reduced  at  (Jorgensen, living  time  gradient,  of  anoxic  within  these  I t very q u i c k l y d i f f u s e s out and elemental  sulphur,  probably  they are well-known i n t e r m e d i a t e s  oxidation  (Chen  82  and  Gupta,  1973).  a  1977)  in  F^S  It  in One  is via the can  t h e r e f o r e speculate on three p o s s i b l e mechanisms by which sulphur can  be  (Fig.  c h e m i c a l l y added to the humic matrix  i n marine sediments  13): Within the microaggregates  react  with  organic  and/or a d d i t i o n . salt-marsh  matter  or the s u l p h i d i c zones, HS through  nucleophilic  Experiments done with  could  substitution  S l a b e l l e d sulphate  sediments show that the r a t e of formation of  in  organic  35 S  is  much lower  sulphides  and  therefore  argue  reaction  pyrite  2  since  before  it  microniches  (Howarth and  Merkel,  that sulphur enrichment of  with H S  zones,  than the r a t e of formation  HS 2  of  acid-volatile  1984).  One  organic  matter  should not occur w i t h i n the o x i c and would be r e a d i l y o x i d i z e d and/or  c o u l d r e a c t with the  organic  matrix.  could by  sub-oxic  precipitated However,  the  s u s t a i n a h i g h r a t e of sulphate r e d u c t i o n so that the  3+ Fe  r e a d i l y a v a i l a b l e w i t h i n the aggregates  and H S 2  to  must d i f f u s e out to be o x i d i z e d ,  produce  continuous will  FeS and F e S  (Berner,  2  pool of f r e e H S 2  i s quickly depleted 2+  while Fe  1969).  diffuses  This w i l l  provide  w i t h i n the microenvironments,  are comparatively  which  slow.  A l t e r n a t i v e mechanisms f o r S a d d i t i o n i n t o sedimentary substances  are p r o v i d e d by the products of H S 2  Polysulphides  They  a  be a v a i l a b l e f o r r e a c t i o n with humic m a t e r i a l s , even i f such  reactions  of  in  HS 2  can  easily  oxidation.  are formed as i n t e r m e d i a t e s of the  or by r e a c t i o n between s u l p h i d e and be  cleaved  homolitically 83  humic  elemental and  oxidation sulphur.  produce  free  a n o x i c  e n v i r o n m e n t s  o x i c / s u b o x i c  HS  HS"  reactions  with HS"  e n v i r o n m e n t s  r  reactions with  nucleophilic attack  polysulphides: nucleophilic  on  S  8  addition ;  H S : + C=A Y'A"  HS:<Sg— H S - S ~  R - S H + S — - R - S - S g + H"  HS-S:-~HSg+Sf  R-NH + S « — R - N - S * + H  8  ASH R - N - S ^ H  nucleophilic  substitution:  H HSf+ - C - ^ Z -  H  + HS:  - C - S H + Z*.  Fig.  13:  P o s s i b l e mechanims of sulphur a d d i t i o n to the o r g a n i c matrix i n the o x i c , s u b - o x i c , and sulphidic zones of nearshore marine sediments (see t e x t f o r e x p l a n a t i o n ) .  84  +  r a d i c a l s which can then r e a c t with organic matter polysulphides reactions  and  eventually  thiol  groups  to form organic  (Fig.  13).  c o u l d occur e i t h e r at a redox boundary or w i t h i n  sulphidic  zone of the sediment column where a pool of  Also, as  amines  elemental also  nucleophilic and  groups  present  thiols)  could cleave  humic  the  Sg  rings  sulphur and produce organic p o l y s u l p h i d e s which  The  associated starts  presence  of  organic  with humic a c i d s ,  polysulphides  to accumulate i n pore water ( F i g .  isotopic  composition  The  of elemental  l a c k of  to  that the elemental sulphur has l i t t l e e f f e c t sulphur-containing  be HS 2  indicate  co-variation  sulphur  and  h y d r o l y z a b l e sulphur i n the humic m a t e r i a l would seem to  non-hydrolyzable  organic  found  11) seems t o  of  could  j u s t above the depth at which  that t h i s type of r e a c t i o n does occur. the  found.  fraction  produce f r e e r a d i c a l s l i a b l e to f u r t h e r react with  matter.  in  in the  the  elemental  sulphur, small but p o s s i b l y with a high turnover r a t e , was  (such  Such  indicate  on the a d d i t i o n  functionalities  non-  in  of the  organic matrix. However, such r e a c t i o n s would have been masked by subsequent i s o t o p i c exchange with the H S 2  Finally,  i f we assume that the S/C  pool. r a t i o s r e p o r t e d f o r humic  acids  r e f l e c t the sulphur content of the humified m a t e r i a l s  since  such  organic  matter,  associated % C g by S/C Q r  m a t e r i a l s would c o n s t i t u t e the bulk  with  an  estimate  of  the o r g a n i c matter  the  proportion  can be made  and comparing i t with the t o t a l 85  of  by  and  sedimentary of  sulphur  multiplying  sulphur content  for  each  depth  interval.  some marine sediments, sulphur  could  sedimentary  Such a c a l c u l a t i o n would suggest relatively  the work of Zhabina organic  sulphur  sulphur  i n marine  REACTIONS  and Volkov  in  organic  the  ranging from ~50% at the sediment  to 15-20% i n the s u l p h i d i c zone.  2.4  r i c h i n o r g a n i c matter,  represent a s i g n i f i c a n t p r o p o r t i o n of  sulphur,  that  total  interface  T h i s c o n t e n t i o n i s supported by  (1978) who found  that,  r e p r e s e n t s the second l a r g e s t pool  as a r u l e , of  reduced  sediments.  BETWEEN  REDUCED  SULPHUR  SPECIES  AND  HUMIC  SUBSTANCES AT SEAWATER pH, UNDER LABORATORY CONDITIONS.  2.4.1 INTRODUCTION.  Reactions  between humic m a t e r i a l s and  sulphides,  elemental  sulphur or p o l y s u l p h i d e s were shown to proceed  r a p i d l y at high pH  (see  s e c t i o n 2.2). In the previous s e c t i o n ,  i t was a l s o argued  that  such  the  reactions  could possibly explain  content o f t e n r e p o r t e d i n humic substances sediments. these  high  e x t r a c t e d from  sulphur marine  In an attempt t o evaluate f u r t h e r the p l a u s i b i l i t y of  mechanisms,  the  r e a c t i v i t y of v a r i o u s i n o r g a n i c  sulphur s p e c i e s was t e s t e d at seawater pH.  86  reduced  2.4.2 METHODS.  Humic  acids,  previously  sediment, were d i s p e r s e d 8.2 with N a C 0 2  colloidal  3  extracted  was then d i v i d e d  p o r t i o n was kept as a c o n t r o l while (pH  8.2) and 0.63mmol/l S  were  added  nitrogen under and  the  elemental  proceeding  2.4.3 RESULTS AND  The after  seawater pH, appreciable 2  In  significant This in  marine  marine  four  12 h r s . The  portions.  One  1.6mmol/l HS  g  (pH8.2) r e s p e c t i v e l y ,  A f t e r having  been  kept  under  the humic a c i d s were r e p r e c i p i t a t e d at  sulphur  The samples were then exhaustively  pH2,  freeze-dried  extracted  with  benzene  analysis.  DISCUSSION.  composition  of the humic  treatments i s shown i n Table  materials  at  the r e a c t i o n s proceed at lower r a t e s . . However,  an  S enrichment was s t i l l  contrast, extent  18.  As  obtained  expected,  and p o l y s u l p h i d e s ,  I8hrs.  into  0.63mmol/l S ,  with t h e i r elemental  elemental  these  oxic  f o r at l e a s t  + 1.6mmol/l HS~  a stream of n i t r o g e n .  before  HS  g  to the three o t h e r s .  f o r I8hrs,  an  i n d i s t i l l e d water and n e u t r a l i z e d to pH  u n t i l the pH s t a b i l i z e d  solution  from  observed i n the  presence  of  even w i t h i n the r e l a t i v e l y short p e r i o d of elemental  sulphur  d i d not react  to  any  w i t h i n the short time span s t u d i e d .  experiment f u r t h e r supports the view that HS~, sediments  by  sulphate-reducing 87  formed  bacteria,  or  Table 18. Sulphur enrichment of humic a c i d s by v a r i o u s sulphur s p e c i e s a f t e r 18 hours of contact at seawater pH (8.2). Wt% HA C  S  S/C  39 .6 + 0.5  1.15+0 .03  0 .029+0. 001  41 .0 + 0. 5  1.15 + 0.03  0 .028+0. 001  HA + s u l p h i d e s  41 .8 + 0. 5  1.53 + 0.04  0 .037+0. 001  HA + p o l y s u l p h i d e s  42 .3 + 0. 5  1.46 + 0.04  0 .035+0. 001  HA c o n t r o l HA + elemental  1.Not  sulphur  ash c o r r e c t e d .  88  polysulphides are  the  main  enrichment other  2.5  sulphur  species  of humic substances  hand,  elemental  conditions. Mango  produced as an intermediate i n o x i d a t i o n  These  responsible  for  of  the  sulphur  during early diagenesis.  sulphur  is relatively  inert  HS ,  On  under  the these  c o n c l u s i o n s are i n agreement with the work of  (1983).  INFLUENCE OF S ENRICHMENT ON THE  COMPLEXING CAPACITY OF HUMIC  MATERIALS.  2.5.1  INTRODUCTION.  Humic  substances  ligands,  each  different  metals.  Ligands at ions  l e a s t one  of  can  which  be viewed as a system will  have  different  (or Lewis bases) are molecules f r e e p a i r of e l e c t r o n s .  On  compounds  or anions  vacant  an e l e c t r o n p a i r and thus can  or complexes with l i g a n d s .  competing  affinities  the other  (or Lewis a c i d s ) c o n t a i n at l e a s t one  can accommodate  of  for  containing hand,  metal  orbital  which  form  coordination  These bonds can be  mainly  e l e c t r o s t a t i c , mainly c o v a l e n t or i n t e r m e d i a t e i n c h a r a c t e r . When one  me.tal  complex.  ion combines with one However, most metal  ligand,  they form a  unidentate  ions are a b l e to c o o r d i n a t e s e v e r a l  l i g a n d s s i m u l t a n e o u s l y . T h e r e f o r e , i f a l i g a n d molecule  contains  s e v e r a l e l e c t r o n - d o n o r atoms, m u l t i d e n t a t e complexes, a l s o c a l l e d 89  Table  19.  Unidentate  ligands  likely  to  be  found  in  humic  mater i a l s . Oxygen  functionalities  alcohols,phenols, "0-  a l k o x i d e , phenoxide  "o c-  carboxylate  :0=C^  aldehydes, ketones, esters  •N-  amines  ~<  amide ions  2  Nitrogen  functionalities  Halogen  functionalities  functionalities  ions  ions  :N=C  Imines, oximes, unsat. heterocycles  *s-  thiolate, ions  :s=c\  thiocarbonyls  :X-  a l k y l , aryl halides  V  Sulphur  ethers  90  thiophenolate  chelates,  can  stability often for  be  formed.  As  a rule,  c h e l a t e s have a  higher  constant than monodentate complexes, and they have been  invoked to e x p l a i n the high a f f i n i t y certain  metals.  A list  of  humic  substances  of unidentate l i g a n d s l i k e l y  found i n humic m a t e r i a l s i s shown i n Table 19.  to  be  Some examples  of  p o s s i b l e b i d e n t a t e l i g a n d s are a l s o shown i n Table 20. Each Summing  l i g a n d has a d i f f e r e n t a f f i n i t y up  stability, bind  the  experimental  Pearson  for different  information a v a i l a b l e  metals.  on  (1968) concluded that hard a c i d s  complex  prefer  to  t o hard bases and s o f t a c i d s p r e f e r to bind t o s o f t  bases.  Hard a c i d s are those e l e c t r o n - a c c e p t o r s with a high i o n i c  charge.  They  have the  valence  shell  electron  c o n f i g u r a t i o n of an i n e r t gas and t h e i r  i s of low p o l a r i z a b i 1 i t y .  " c l a s s - a " metals of Ahrland et a l . with  (1958), and w i l l  react  O - c o n t a i n i n g groups (known as hard bases) and to  extent  with N - c o n t a i n i n g groups.  mainly e l e c t r o v a l e n t of  They correspond to  Metals  of  mainly  a  lesser will  be  i n c h a r a c t e r , which means that the s t a b i l i t y  these complexes w i l l  metals.  The bonds so produced  the  i n c r e a s e with the i o n i c charge of  this  type w i l l  include  the  alkalis,  these the  a l k a l i n e e a r t h s , the l a n t h a n i d e s , the a c t i n i d e s and A l ( F i g . 14). On the other hand, s o f t a c i d s (or " c l a s s - b " metals) are e l e c t r o n a c c e p t o r s of r e l a t i v e l y charge.  They  also  l a r g e atomic  possess  size,  unshared  i . e . with a low i o n i c  electron pairs in p  o r b i t a l s or t h e i r h y b r i d s i n t h e i r valence s h e l l s . shells  will  be h i g h l y p o l a r i z a b l e and w i l l 91  form  or  d  These valence bonds  with  a  Table 20.  Some examples of bidentate ligands possibly present in  humic materials (after Houghton, 1979).  92  '/./.- De Na  Mg Ji  Cs^'Ba  ^ La  V \ Cr^-Mri^  Fe 'Co ^Ni  >CuA;Zn  Rh~P6-Ag [Cdy I n \ S r t < S 6 "  Zr  Nb M o  Tc  Ru :  Hf  Ta  Re  Os _ | — Pt -A'u  W  r  -'Hg =J\-^Pb±:Q\=  Te  /  Xe  Po  At  Rn  •Fr - Ra ^ A c Lanthanides  C Z J Class A I ~ i Qorderhne f==^ Class B  ' ' / ^ Nd ' P m - S m  .Ce-  /  r .  " W  Lu"  Fm'Md'  Li'.  T b ^ D y -' H o ' "Er  /  x  /  Pa  "u • ^ N p ^ P u ' ' A m " C m ' B k ^ C f ' Es  Actinides  Fig.  14:  The p e r i o d i c t a b l e of the elements showing the distribution of the " c l a s s - a " , " b o r d e r l i n e " and "class-b" metal and m e t a l l o i d ions ( a f t e r Nieboer and Richardson, 1980).  93  highly  covalent  character.  "Class-b"  metals  will  particularly  stable  period  P, S, and C l ) , p r i m a r i l y because of the p o s s i b i l i t y  (i.e.  complexes with donor-atoms from  form  the  third  of  forming T|-bonds with the unshared e l e c t r o n p a i r of the metals  and  empty d - o r b i t a l s of the donors (Ahrland,  1966).  Such  are not p o s s i b l e with the elements of the second p e r i o d 0,  and  F)  ions  shells. the  (i.e.  because t h e i r valence o r b i t a l s are at a much  energy l e v e l than the 3d o r b i t a l s . metal  bonds  with  "Class-b"  will  t y p i c a l l y 8 to 10 e l e c t r o n s  In the p e r i o d i c t a b l e ,  be  in  N,  higher  transition  their  valence  they occupy a t r i a n g u l a r zone t o  r i g h t of the t r a n s i t i o n s e r i e s ( F i g . 14). In sea water, t h e i r  speciation  may  Whitfield,  The  i s gradual,  configuration  of  between  therefore, (Fig.  dominated by  1983).  character  boundary  be  change  since  the  chloro-complexes from  "class-a"  i t i s controlled  elements and there  the two types of  metals.  to  by  electron  wellis  and  "class-b"  the  i s no It  (Martin  defined  convenient,  to d i s t i n g u i s h i n the p e r i o d i c t a b l e a b o r d e r l i n e  zone  14) which w i l l encompass many of the t r a n s i t i o n elements of  interest  in  properties "class-b"  environmental chemistry.  intermediate character  (i.e.  their  Their  selectivity  they  will  particularly  between " c l a s s - a " and  will  increase  "class-b" character  also  These elements w i l l  as t h e i r d - o r b i t a l s  will  f o r s o f t bases w i l l strongly  interact  increase  upon  with  hard and  Their  fill  up  reduction).  not be as marked  with N-containing groups (Nieboer 94  "class-b".  have  so  that  bases,  and  Richardson,  1980).  Also,  i n sea water,  t h e i r chloro-complexes w i l l be l e s s  dominant than f o r the s t r i c t l y Humic and  such  substances a r e p o t e n t i a l l y important metal associations  discrepancies  been  functionalities  implied  to  humic polymers  explain  an a p p r o p r i a t e  in  contain a  ( s o f t and hard bases)  form u n i d e n t a t e c o o r d i n a t i o n  ions i n aqueous s o l u t i o n s . in  often  As shown i n Table 19,  v a r i e t y of complexing readily  have  complexers  between observed and p r e d i c t e d metal behaviour  n a t u r a l systems.  will  " c l a s s - b " metals.  compounds with  which metal  I f these l i g a n d groups a r e p o s i t i o n e d  steric configuration,  multidentate  complexes  c o u l d a l s o be formed. Extensive  studies  of  the s t r u c t u r e  substances by a v a r i e t y of independent many  of  carboxyl (1965)  their  noted  purified  a  soil  functionalities. many  of  consist  f u n c t i o n a l groups.  sharp decrease i n the humic  acids  Oxidative  accepted  substances  the  Schnitzer  chemically  groups  Schnitzer,  i s the r e s u l t of (Fig.  and  complexing  capacity  humic  i n the ortho  interactions  of  these that  substances position  1978). I t has t h e r e f o r e of  of  Skinner  blocking  that the complexing c a p a c i t y  groups and metal ions  presence  degradation s t u d i e s a l s o suggest  of c a r b o x y l i c and p h e n o l i c  generally  by  the " b u i l d i n g b l o c k s " of t e r r e s t r i a l  on a benzene r i n g (e.g.  humic  after  t e r r e s t r i a l humic  techniques have shown that  p r o p e r t i e s a r e determined  and phenolic  of  been  terrestial  between  such  15). Recently, an ESR study (Boyd et  95  \  .-oo  J-0H  \  + M  2+  ;» —  '-C-0H  -c-o N M  H  -0  0  , Q  \-c-o-  9  + M  2+  ^ ^:  ,  Vc-G\ M  H  J-c-o" 0  Fig.  15: C h e l a t e f o r m a t i o n between o - h y d r o x y c a r b o x y l i c acids, o-dicarboxylic a c i d s and d i v a l e n t metal i o n s .  96  al., two  This  and F e  + +  of  ) supported t h i s c o n c l u s i o n by showing  that Cu  ++  e q u a t o r i a l bonds i n c i s - p o s i t i o n with oxygen atoms of  acids. Cu  a  1981  one,  model i s a l s o c o n s i s t e n t with the I.R. humates (Boyd et a l . ,  + + +  otherwise  a d d i t i o n of C u 1971).  (Beckwith,  + +  Therefore,  substances  will  +  from  fulvic  1959; Gamble et a l . , with a  acids  upon  1970; Van  Dijk,  given  r o l e i n metal complexation ( P i c c o l o and  humic  such  and as  i s g e n e r a l l y b e l i e v e d to be minor,  although  t h e i r p o t e n t i a l as complexing s i t e s  Malcolm,  1985). Whether or not humic polymers w i l l  metal  ions  hydroxycarboxylic That  Stevenson,  1985). On the other hand, the i n f l u e n c e of N and  S - c o n t a i n i n g f u n c t i o n a l groups  moieties.  metal,  Other O - c o n t a i n i n g f u n c t i o n a l groups,  Stevenson,  with  of  1981^) and with the r e l e a s e H  saturated  spectra  ketonic s t r u c t u r e s and quinone groups c o u l d a l s o p l a y  a significant 1981;  when  humic  form c o o r d i n a t i o n compounds with c a r b o x y l i c  p h e n o l i c groups. conjugated  untitratable,  forms  will acids  depend or  on  similar  the  i s recognized (e.g. form c h e l a t e s  occurrence  sterically  of  o-  appropriate  such groups are a main component of s o i l o r g a n i c  matter seems w e l l e s t a b l i s h e d . On the other hand, humic m a t e r i a l s from marine environments d i s p l a y a much more a l i p h a t i c (Stuermer and Payne, 1976;  Stuermer  1980), have a lower t o t a l a c i d i t y (Vandenbroucke relative  to  Kaplan,  1972;  et their  a l . , 1985)  et a l . ,  1978; Hatcher et a l . ,  ( p a r t i c u l a r l y phenolic  acidity)  and a l s o are e n r i c h e d i n N and  terrestrial  Stuermer  et a l . ,  character  counterparts  (Nissenbaum  S and  1978). C o n s i d e r i n g these f a c t o r s , 97  and  a l s o i n the l i g h t of Ahrland's c l a s s i f i c a t i o n of metals, i t  may  not  be  true  functionalities been  that  will  i n marine  environments,  O-containing  have the o v e r r i d i n g importance  a t t r i b u t e d t o them f o r the complexing  i n t e r r e s t i a l environments.  which  of t r a n s i t i o n  In sea water,  metals  and p a r t i c u l a r l y when  the DOC i s low, the t r a n s i t i o n metals must compete with M g Ca  + +  has  + +  and  a t c o n c e n t r a t i o n s orders of magnitude higher than t h e i r own.  Therefore,  i n order t o be complexed,  these metals w i l l have  to  react  with l i g a n d s having a very high degree of s p e c i f i c i t y f o r  them.  The  degree of s p e c i f i c i t y w i l l be more important  degree of s t a b i l i t y of the complexes so formed, stable  unidentate  complexes,  highly  metals, w i l l be much more important sea Mg  i . e . even  specific  to  f o r t r a c e metal  are t y p i c a l  " c l a s s - a " metal's  and  p r e f e r e n t i a l l y with O-containing groups.  speciation in  also  therefore  have strong  containing  groups and the s t a b i l i t y constant of t h e i r  difference metals  and  affinities  Mg .  groups  may not be  override  the c o n c e n t r a t i o n e f f e c t .  tend  support  Nevertheless,  this  many  view  98  large  Thermodynamic  ( e . g . Mantoura  independent  and  react  experimental  f o r 0complexes  However, the  ++  i n the s t a b i l i t y constants of these two  f o r O-containing  to  + +  + +  T r a n s i t i o n elements, as  metals,  i n many cases higher than f o r C a  Ca  will  borderline  are  will  less  transition  water than more s t a b l e but l e s s s p e c i f i c c h e l a t e s .  + +  than the  c l a s s e s of enough  to  calculations  et  al.,  studies  1978). have  indirectly  demonstrated  the e x i s t e n c e  compounds i n sea water (e.g. be understood  and  S - c o n t a i n i n g groups present  and  Mg  by c o n s i d e r i n g the complexing a b i l i t i e s of Ni n marine humic  w i l l only form r e l a t i v e l y  functional  and  illustrated  "class-b"  in Fig.  steric Ba ,  Sr  + +  + +  corresponds  period,  with  + +  , and M g  + +  t o Zn  are t y p i c a l  from  to C u  speculate  with  and  Mn  + +  i s well  of a s e r i e s  McCormick,  "class-a"  metals,  ( i n the order g i v e n ) , while  t o the second h a l f of the f i r s t "class-b"  + +  could  metals  such  ( a l s o known as the I r v i n g - W i l l i a m s  increasing  for Zn .  (Sigel  + +  character  and a  The much higher  that most  still  in "class-b"  s p e c i f i c i t y of  complexed  transition  (although  decrease  t h i o l groups f o r t r a n s i t i o n metals i s c l e a r l y one  amine  and  shown.  Similarly,  bivalent  transition  a predominant " c l a s s - b " c h a r a c t e r w i l l be found  in  sea water a s s o c i a t e d with S- and N - c o n t a m i n g groups, while Ca Mg  + +  and A l  +  +  +  will  s a t u r a t e O-containing  with a predominant " c l a s s - a " c h a r a c t e r , not  be  ++  N, and S - c o n t a i n i n g groups of  "class-a" character  series)  character  Ca  with  phenomenon  16 where the s t a b i l i t y constants  , Ca  s e r i e s from Mn  "borderline")  This  c o n f i g u r a t i o n are shown  but of d e c r e a s i n g the  l a b i l e complexes  metals.  of b i v a l e n t metals with v a r i o u s 0,  1970).  polymers.  groups which w i l l have a much higher s e l e c t i v i t y f o r  transition  similar  organo-metallic  Mantoura, 1981). T h i s c o n t r a d i c t i o n  may  + +  of  organically-bound to a  groups.  Trace  metals  such as Mn and Fe,  significant  extent,  ,  while  will the  s p e c i a t i o n of " c l a s s - b " metals (e.g. H g , P b , C u ) w i l l be the + +  99  + +  +  I  F i g . 16: L o g a r i t h m s o f t h e s t a b i l i t y c o n s t a n t | f o r t h e 1 : l c o m p l e x e s between Ba through Zn and t h e bidentate ligands oxalic acid, glycine, ethylenediamine, mercaptoacetic a c i d , and m e r c a p t o e t h y l a m i n e ( a f t e r Sigel and Mccormick, 1970). +  100  result  of  competition  s i m i l a r l y s o f t organic  between  on  and  organic  sulphur  i t can be concluded that  i n humic m a t e r i a l s c o u l d have a s i g n i f i c a n t  their  complexing c a p a c i t i e s with  "class-b"  metals.  hypothesis,  As  or  bases.  From the above d i s c u s s i o n , enrichment  Cl  a  respect t o  p r e l i m i n a r y experiment  sulphur  influence  transition to  test  and this  the i n f l u e n c e of sulphur-enrichment on the formation  of non a c i d - l a b i l e Cu -humic complexes was i n v e s t i g a t e d . ++  2.5.2  METHODS.  An  outline  of the procedure followed  i s presented  in  17. One hundred mg of a humic a c i d e x t r a c t e d from a p o d z o l i c was  dispersed  A f t e r c e n t r i f u g a t i o n and thorough r i n s i n g ,  dispersed  i n d e i o n i z e d water and brought to pH 7.8 with  overnight  recovered was  equilibrate.  by f i l t r a t i o n  two  portions, for  to  The d i s s o l v e d  i t was r e NaOH and  materials  (on 0.45>um Nucleopore f i l t e r s ) ,  portions. while  divided  25-30 mmol/1 Na S was added to one 2  the other was kept as a c o n t r o l .  After  were  0.5N NaOH  added t o the s o l u t i o n under n i t r o g e n and then i t was  into  soil  i n 0.1N HC1/0.3N HF f o r I8hrs to decrease i t s ash  content.  left  Fig.  of the standing  40hrs, the s o l u t i o n s were a c i d i f i e d t o pH~2, with HC1 and the  excess  H S 2  materials water  driven  o f f with n i t r o g e n .  The  precipitated  were c e n t r i f u g e d and r i n s e d with de-aerated  and r e - d i s s o l v e d a t pH 7.5-8. 101  Ten mg C u  + +  humic  deionized  (as 10ml  of a  extracted dispersed  Humic a c i d s from p o d z o l i c s o i l  I  i n 0.3N HF/0.1N HC1  I  centr. brought  (18hrs)  & rinsed  I  t o pH7.8 ( w i t h c h e l e x - c l e a n e d NaOH) l e f t overnight filtered  through  I  0.45um  insol. discarded  filtrate + NaOH (0.5N)  I  I  +25-30mmol/l S~ 4 0 h r s , u n d e r N_  40hrs,  under  N  2  •J*  I  I  centr. & rinse (with de-aerated d e i o n i z e d water)  centr.  re-dissolved  & rinse  a t pH 7.5-8  +10ml lOOOppm Cu i n 0.3N HNO, e q u i l i b r a t e f o r 18hrs  •J*  I centr. wash w i t h re-dissolved  & decant  I  0.1N H C l , ~ 2 h r s , 2X  I  i n "Chelex"cleaned  I  re-precipitated  I  rinse with re-dissolved  w i t h HC1  0.1N H C l (2X)  I  i n 10ml 0.5N NaOH  determination  0.5N NaOH  I  (Chelex-cleaned)  o f C & Cu c o n c e n t r a t i o n s  I  r e - p r e c i p i t a t e d with HCl centr.  I  freeze-dried  I  17:  C & S analysis P r o c e d u r e f o l l o w e d i n t h e e x p e r i m e n t on t h e i n f l u e n c e o f S - e n r i c h m e n t on t h e Cu r e t e n t i o n o f humic s u b s t a n c e s .  102  1000ppm s o l u t i o n in 0.3N for  18 h r s .  6.3  f o r the S-enriched  few.  drops  Cu  were added and  A f t e r measuring the pH  of HC1  centrifuged material  HNO^)  was  m a t e r i a l and  were added and  of e q u i l i b r a t i o n  with 0.1N  then f i n a l l y d i s s o l v e d i n 0.5N of  this  solution  was  determined f o l l o w i n g the procedure e x p l a i n e d Cu  c o n c e n t r a t i o n was  furnace  atomic  dilution  in  measured by d i r e c t  absorption  distilled  and  (pH 6 and  pH  the c o n t r o l , r e s p e c t i v e l y ) , a  the p r e c i p i t a t e d  and washed thoroughly  concentration  l e f t to e q u i l i b r a t e  HC1.  The  was  recovered  NaOH and  the DOC  and  measured.  DOC  was  in Appendix I I .  i n j e c t i o n on a  spectrometer, deionized  material  after  water,  The  graphite  appropriate  (precision:  +4%).  Subsequently, the humic a c i d s were r e - p r e c i p i t a t e d , f r e e z e - d r i e d , and  2.5.3  t h e i r sulphur  and  RESULTS AND  carbon contents  DISCUSSION.  It can be seen that was acid  retained  by  with  upon sulphur  enrichment,  An increase  washing  T h i s i s c o n s i s t e n t with the hypothesis  in  that  can provide b i n d i n g s i t e s for t r a n s i t i o n  a predominantly " c l a s s - b " c h a r a c t e r  difficult  much more Cu  the humic m a t e r i a l a f t e r thorough  (Table 21).  functionalities  measured (see appendix I I ) .  S  metals  from which they w i l l  be  to d i s p l a c e . increment in  corresponds  of  7.6  x 10  r e t a i n e d Cu of 0.61 to  the  gr-at.S/gr-at.C x 10  b i n d i n g of 0.08 1 03  produced  gr-at.Cu/gr-at.C. gr-at.Cu/gr-at.S  or  an This 0.16  Table  21.  Influence  washed t e r r e s t r i a l  of S enrichment on the Cu r e t e n t i o n of a c i d -  humic m a t e r i a l s . Wt% HA  atomic r a t i o s %Cu  3  Samples  %C  %S  humic a c i d s  51.4  0.33  0.25  2.37+0.08  0.93+0.05  S enriched humic a c i d s  48.0  1.28  0.39  9.99+0.35  1.53+0.08  104  S/C  (10~ ) Cu/C  gCu/gC. the  If  we assume that the same Cu/S  initial  containing 0.325%  humic 0.325%  X  0.16)  material S),  of  used  to ~20%  conditions,  the Cu bound to the  non  (i.e.  0.052%  (i.e.  S-enriched  humic  assuming that the sulphur  r e t a i n e d under  This these  added by r e a c t i o n with  nature as the sulphur  initially  HS  present.  shows the p o t e n t i a l of S as a b i n d i n g s i t e f o r Cu,  the in  experiment  for  bound to S f u n c t i o n a l i t i e s .  of the t o t a l Cu which was  i s of the same chemical This  this  i t can be c a l c u l a t e d that  m a t e r i a l a f t e r a c i d washing was amounts  in  r e l a t i o n s h i p holds  even i n  case of t e r r e s t r i a l humic m a t e r i a l s which are t y p i c a l l y this  type of l i g a n d .  functionalities matter and  to  influence marine  in  pore waters at c o n c e n t r a t i o n s which g r e a t l y exceed  the  1968;  P r e s l e y et a l . , 1972;  able to maintain are  E l d e r f i e l d and Hepworth, 1985).  acids  ( i . e . hard bases) would not  the c o n c e n t r a t i o n s  g e n e r a l l y observed  calculations  be  of metals in s u l p h i d i c waters  (Gardner,  1974).  s t r o n g l y suggest t h a t b i s u l p h i d e  (i.e.  solubility.  (Brooks et  thermodynamic c a l c u l a t i o n s would i n d i c a t e that amino-  a c i d s and h y d r o x y c a r b o x y l i c  anions  organic  v a r i o u s t r a c e metals have been found  Here a l s o ,  which  S  during e a r l y d i a g e n e s i s .  values expected from the s o l u b i l i t y of t h e i r s u l p h i d e s al.,  of  f o r sedimentary humic m a t e r i a l s which can  i n sulphur  In many i n s t a n c e s , sulphidic  would expect the  be much more pronounced f o r  particularly  become e n r i c h e d  One  low  and  Instead,  such  polysulphide  s o f t bases) w i l l be the main agent f o r t r a c e metal  Nevertheless,  a d i r e c t a s s o c i a t i o n between organic 105  polymers  and  interstitial 1976;  various waters  Elderfield,  involved  transition  metals  has been reported  in  sulphide-bearing  (Nissenbaum  1981). Organic sulphur  and  Swaine,  f u n c t i o n a l i t i e s may be  i n t h i s a s s o c i a t i o n and f u r t h e r study of t h e i r r o l e may  help solve t h i s apparent c o n t r a d i c t i o n . Copper associated  i s o f t e n the t r a n s i t i o n metal found with organic  i t s greater  matter.  most  closely  Although t h i s i s c o n s i s t e n t  "class-b" character,  there are a l s o i n d i c a t i o n s that  i t s redox p r o p e r t i e s may be d i r e c t l y  involved  i n i t s behaviour.  It has been demonstrated that Cu(II) can be r a p i d l y by a h e a t - k i l l e d suspension of E ^ or  a l c o h o l dehydrogenase,  1980). or  Since  reduced  c o l i , and s o l u t i o n s of c y s t e i n  under anaerobic c o n d i t i o n s  such r e d u c t i o n  (McBrien,  does not occur when the c e l l  the p r o t e i n s o l u t i o n s are p r e - t r e a t e d with a reagent  t h i o l groups (N-ethylmaleimide),  with  extract blocking  i t has been concluded that  Cu  + +  c o u l d be reduced by s u l p h y d r y l groups, v i z  2 Cu  Cu  +  + +  + 2 R-SH  i s very  according  „  Cu  +  > R-S-S-R + 2 C u  unstable  „ ++  > Cu  + 2 H  +  under oxic c o n d i t i o n s and o x i d i z e s  to , v i z  + CU  +  „ -  + 0„  106  readily  thus producing superoxide r a d i c a l s et a l . ,  1984).  stable  However,  (Moffet and  i n the absence of  and can react with o r g a n i c matter.  "class-b"  character  Zika,  of Cu,  or F e Upon  1983; + + +  Wong  ,  Cu  reduction,  and t h e r e f o r e i t s a b i l i t y  +  is the  to  -form  c o o r d i n a t i o n compounds with s o f t bases,  i n c r e a s e s . Consequently,  the  association  likelihood  of f i n d i n g Cu i n c l o s e  with  thiol  groups i s a l s o i n c r e a s e d . The and  a b i l i t y of C u  + +  to d i s p l a c e other metals  Cd  Z n ) from S - c o n t a i n i n g p r o t e i n s ( m e t a l l o t h i o n e i n s ) i s  also  Suzuki and M a i t a n i , 1981). Such displacement i s  accompanied ++  paramagnetic  Cu  by  a  disappearance  of  ions, presumably due  Considering matter,  been  .  +  so produced  with the remaining s u l p h y d r y l  previously  the . h i g h  1980).  under anoxic c o n d i t i o n s ,  (with a l e s s e r  Cu  + +  readily  functionalities,  " c l a s s - b " c h a r a c t e r ) which  complexed  sulphur content  of +  and t h e r e f o r e E S R - i n a c t i v e (McBrien,  d i s p l a c i n g other metals have  signal  to t h e i r r e d u c t i o n to Cu ,  a b l e to o x i d i z e t h i o l groups and the C u  could  ESR  .  I t has t h e r e f o r e been argued t h a t ,  complexes  the  .  which i s diamagnetic  forms  + +  well  + +  documented (e.g.  is  (such as  by of  them  (Fig.  sedimentary  18).  organic  such a mechanism c o u l d c o n c e i v a b l y be very important f o r  the s p e c i a t i o n of Cu i n suboxic and anoxic pore  107  waters.  -S-Cu(I)  -S-Zn(II) -SH  +  CU ++  >  -SH  Pig,  18:  -S I -s  Zn  ++  R e a c t i o n between Cu and S - c o n t a i n i n g p r o t e i n s under a n o x i c c o n d i t i o n s .  1 nfl  3. THE  INFLUENCE OF HUMIC SUBSTANCES ON THE GEOCHEMISTRY OF IODINE IN NEARSHORE AND HEMIPELAGIC MARINE SEDIMENTS.  3.1  INTRODUCTION.  The work of Vinogradov (1939), S h i s h k i n a and Pavlova (1965), P r i c e et a l . and  Price  and  (1970),  (1980),  W a k e f i e l d and E l d e r f i e l d  Elderfield  geochemistry  Bojanowski and Paslawska  (1987)  appears  to  (1970), Pedersen  (1985),  demonstrate  and Kennedy that  of i o d i n e i n marine sediments i s c o n t r o l l e d  the almost  e n t i r e l y by i t s a s s o c i a t i o n with organic matter. T h i s a s s o c i a t i o n is  q u i t e complex  because the  1  /  c o r  g  r a t i o s of d i f f e r e n t  deposits  vary with the redox c o n d i t i o n s p r e v a i l i n g d u r i n g d e p o s i t i o n , with  the source and t h e r e f o r e the nature of the  present.  Thus,  surficial higher and  P r i c e and C a l v e r t  sediments  I/C g Q r  Malcolm  had  and where  substantial,  the  higher c o n c e n t r a t i o n s  Price  (1984)  oxygenated  showed  that  of  oxic  iodine  in  and area,  nearshore  I content was higher where the organic  nearshore  matter  showed that  input of t e r r e s t r i a l organic matter  was predominantly of p l a n k t o n i c  content  1977)  r a t i o s than anoxic sediments from the same  environments  In  (1973,  organic  and  can  be  matter  origin. environments,  both  the  iodine  and l/C„„„ r a t i o o f t e n decrease with depth from v a r i a b l e org 1 09  surface  values  to those t y p i c a l l y  e n t i r e l y anoxic, et  al.,  by the  1970;  where no I or I/C P r i c e and C a l v e r t ,  p r e f e r e n t i a l diagenetic  organic  matter.  iodine  in  Price,  1980;  the  et  with  evidently enriched and/or  a l . , 1981)  (Pedersen  and the  from sediments,  this  general  scheme.  in  i o d i d e by p l a n k t o n i c  (1973,  only  that  because plankton,  decaying these  when  the  surface of  t r i p t o n at the sediment/water i n t e r f a c e v i a  scavenge  but  lost  conditions.  (iodide-oxidase)  (Shaw,  plankton  adsorbed  This  1962). T h i s p o s s i b i l i t y has  i o d i n e from seawater  not under oxygen-free  algae.  which i s a c t i v e  been supported by Malcolm and P r i c e (1984)  conditions  is  sediments  o x i c sediments was due to the a d s o r p t i o n  i n oxygenated c o n d i t i o n s  plankton  iodine  and p a r t i a l l y  1977) proposed that  i s mediated by an enzyme  recently  when  conditions,  Hence,  r e a c t i o n s s i m i l a r to the uptake of i o d i d e by marine uptake  iodine  especially  by some mechanism i n s u r f i c i a l o x i c  and C a l v e r t  and  experimental  under anoxic  these same sediments are b u r i e d under anoxic  enrichment of I  dissolved  (1983), which showed that more  s e t t l i n g particulate materials,  Price  explained  of  sediments  o x i c sediments were incubated  consistent  are  are found ( P r i c e  1973). T h i s has been  pore waters of marine  Elderfield  that  r e l e a s e of i o d i n e from the b u r i e d  r e l a t i v e t o carbon was r e l e a s e d  are  gradients  Observations of the d i s t r i b u t i o n  r e s u l t s of Ullman and A l l e r  surficial  found i n sediments  under  conditions. more  iodine  who  showed  oxygenated Furthermore, than  fresh  authors suggested that t h i s scavenging c o u l d be 110  the  r e s u l t of b a c t e r i a l uptake rather than d i r e c t a d s o r p t i o n  plankton An in  debris. a l t e r n a t i v e e x p l a n a t i o n f o r the s u r f a c e enrichment of  terrigenous,  proposed mainly  by  by due  nearshore  marine sediments has  Ullman and A l l e r to  precipitated  (1985).  the a d s o r p t i o n of  at  the  recently  They argued that  iodate  by  Fe  I  been  it  was  oxyhydroxides  s u r f a c e of oxic sediments as a  result  of  d i a g e n e t i c r e m o b i l i z a t i o n . They reached t h e i r c o n c l u s i o n from the o b s e r v a t i o n that there was no s u r f i c i a l upper h o r i z o n of a was  consistent  Fe-poor,  i o d i n e enrichment i n  c a l c a r e o u s sediment. T h i s mechanism  with l a b o r a t o r y experiments  demonstrating  well-known scavenging a b i l i t i e s of Fe oxides f o r iodate et a l . , Aller,  1958;  Whitehead,  1974; Music et a l . ,  1985). The decrease i n I/C  with  the  (Sugawara  1980; Ullman and  r a t i o with depth would then org  reflect  the  r  the r e d u c t i v e d i s s o l u t i o n of Fe oxyhydroxides upon b u r i a l  simultaneous  release  of the adsorbed i o d i n e to  the  pore  waters. In account  the both  present study, for  the  a t h i r d mechanism  surficial  iodine  is  proposed  enrichment  in  sediments and i t s r e l e a s e from the sediment d u r i n g b u r i a l , on o b s e r v a t i o n s of the p a r t i t i o n i n g of i o d i n e i n marine  to oxic  based  sediments  and on l a b o r a t o r y experiments on the uptake and r e l e a s e of i o d i n e by and from sedimentary organic matter.  1 1 1  3.2  MATERIALS  A v a r i e t y of sediments, showing v a r i a b l e i o d i n e enrichments, was s e l e c t e d  f o r study.  A bulk hemipelagic sediment sample  (HUD  22) was c o l l e c t e d from the top ~8cm of a box-core r a i s e d from the Eastern water  Subtropical depth.  recovered  Nearshore  organic-rich,  109°12.8' W i n 2768m  fine-grained  muds  by g r a v i t y c o r i n g and by grab sampling from two  f l u s h e d B.C. ranging  P a c i f i c at 20°53.6' N,  from  centrifugation  f j o r d s (Hastings 200m  to  600m.  following  well-  Arm, J e r v i s I n l e t ) i n water depths Pore  waters  sediment e x t r u s i o n  atmosphere, and the s o l i d - p h a s e  were  were  extracted  under  a  by  nitrogen  samples were p r e s e r v e d f r o z e n .  3.3 METHODS. 3.3.1 ANALYTICAL METHODS. The  details  of  the a n a l y t i c a l methods used are  given  in  Appendix I I . 3.3.2 EXPERIMENTAL METHODS. 3.3.2.1  PARTITIONING OF IODINE IN SEDIMENTS.  3.3.2.1.1 OXYHYDROXIDE PHASE. Duplicate  subsamples  of d r i e d sediment  (8g)  were  treated  with 250 ml of hydroxylamine h y d r o c h l o r i d e / a c e t i c  a c i d f o r 4 h at  room temperature,  by  f o l l o w i n g the method d e s c r i b e d 112  Chester and  Hughes (1967). T o t a l i o d i n e was measured i n the sediment and  that  phases and  was  fraction  of the I a s s o c i a t e d  values.  d u r i n g treatment.  hydroxylamine  treatment  from  the  of  iodine  checked by d u p l i c a t i n g the  i n the presence of r e s o r c i n o l  (see  text  s o l u b i l i z e d were  the Fe and Mn c o n c e n t r a t i o n s i n the l e a c h a t e  measured by atomic a b s o r p t i o n spectrophotometry. + 3%  untreated  The p o s s i b l e r e - a d s o r p t i o n  e x p l a n a t i o n s ) . The amounts of oxyhydroxides  estimated  oxyhydroxide  Allowance was made f o r the l o s s of  r e l e a s e d d u r i n g the r e d u c t i o n step was  for  the  estimated from the d i f f e r e n c e between  t r e a t e d sediment  weight  with  residue,  (10", n = 1 1 ) and +4.5%  as  P r e c i s i o n s were  (10", n=l3) f o r Fe and Mn  respectively.  3.3.2.1.2 HUMIC MATERIALS Humic NaOH  under  substances were e x t r a c t e d from the sediments by nitrogen  (Appendix  measured i n the humic e x t r a c t s  II).  (Appendix  r e s i d u e by the same techniques  Iodine  and  carbon  I I ) and on the  0.5N were  sediment  as those used f o r bulk sediments,  making allowance f o r the change i n weight due t o the e x t r a c t i o n . 3.3.2.2 UPTAKE OF IODINE BY HUMIC SUBSTANCES. 3.3.2.2.1 PRELIMINARY EXPERIMENT: Freeze-dried dispersed mmol/1  KI  conditions.  in or  humic substances with a known I/C  100 ml of f i l t e r e d 1  mmol/1  KJOg  After f i l t r a t i o n  seawater for  4  ratio  were  s p i k e d with e i t h e r  days  under  1  oxygenated  and thorough r i n s i n g with d e i o n i z e d  water, they were f r e e z e - d r i e d and t h e i r I/C r a t i o  1 13  re-measured.  3.3.2.2.2 REACTION BETWEEN HUMIC SUBSTANCES AND Two weight) with  samples  finely  ground humic  were d i s p e r s e d i n 10 ml d i s t i l l e d  2.5  mmol/1  stirring. two  of  K I 0  3  and kept  in  then  water.  water  control,  to pH 2.5-3  similar  suspension  f o r I8h.  way.  The  dry  (pH 2.5-3) spiked by  continuous added. The  The humic  comprising 2.5 mmol/1 KIO^  material distilled  and  resorcinol,  but without humic m a t e r i a l s , was  treated in a  samples c o n t a i n i n g r e s o r c i n o l  with e t h y l a c e t a t e and the e x t r a c t s were checked of  (0.2g  recovered by c e n t r i f u g a t i o n and r i n s e d with A  brought  material  To one sample, 2.5 mmol/1 of r e s o r c i n o l was  samples were shaken i n the dark  was  IODATE:  were  extracted  f o r the presence  i o d i n a t e d r e s o r c i n o l compounds by t h i n l a y e r chromatography on  Si02. 20%  A d e v e l o p i n g s o l v e n t mixture c o n t a i n i n g 80% c h l o r o f o r m and e t h y l a c e t a t e was  resorcinol  and  found to g i v e the best s e p a r a t i o n  i t s iodinated derivatives.  the r e s o r c i n o l d e r i v a t i v e s was A s i m i l a r experiment 0.3  g  of humic m a t e r i a l was  water and brought iodate days  was  and  dialyzate  then was  i o d i d e and H presence carbon and  of  +  performed  at pH 7.5-8. In t h i s case,  d i s p e r s e d i n 100  against  f r e e of i o d a t e .  ml  of  distilled  before adding the potassium  The humic s o l u t i o n was  dialysed  i d e n t i f i c a t i o n of  confirmed by mass spectrometry.  to pH 8 with Na^O^  (2.5 mmol/1).  The  between  deionized  Iodate was  l e f t to stand f o r 5 water  detected  until by  the adding  to an a l i q u o t of the d i a l y z a t e and scanning f o r the 1^  on a spectrophotometer.  The d i s s o l v e d  organic  i o d i n e were then determined as e x p l a i n e d above. 1 14  3.3.2.2.3 RELEASE OF IODINE FROM HUMIC Humic  substances,  SUBSTANCES.  p r e v i o u s l y e n r i c h e d i n i o d i n e by r e a c t i o n  with iodate at pH 3.4, were r e - d i s p e r s e d i n f i l t e r e d , seawater  s p i k e d with e i t h e r  12-15 mmol/1 s u l p h i d e (pH 8.0) or  mmol/1 N a S 0 2 (pH 7.0),  and  before re-measuring t h e i r  i o d i n e content.  2  The pH  2  5  kept f o r 56 h i n a t i g h t c o n t a i n e r  humic substances e x t r a c t e d from HUD 22 were brought  8.5  with HC1,  portions.  and the c o l l o i d a l e x t r a c t was d i v i d e d  15-20mmol/l s u l p h i d e  added to one h a l f only, under  oxygen-free  nitrogen,  dialysed  2  and both p o r t i o n s were kept f o r 4  deionized  two  (as Na S n e u t r a l i z e d t o pH8) was  in tight containers.  against  in  to  water  Subsequently, and  their  I/C  days,  they  were  ratio  re-  determined as b e f o r e .  3.4 RESULTS AND  DISCUSSION.  3.4.1 THE PARTITIONING OF IODINE IN MARINE  The  d i s t r i b u t i o n of I between the oxyhydroxide and  phases  of  simple  leaching  a  T h i s sediment i n the of  SEDIMENTS.  I/C  org  marine sediment was e v a l u a t e d by experiment  r a t i o with depth, (Fig.  carrying  out  on the hemipelagic sediment HUD  shows the common s u r f i c i a l  f r e e oxyhydroxide  organic  19;  22.  I enrichment, a decrease  and c o n t a i n s a moderate Pedersen et  1 15  a  a l . , 1986).  amount This  l/CorgOO" ) 200 300 4  0  100  0  0.3  Mn wt% 0.6  0.7  0.9  1.2  08  0.9  Fe/Al Fig.  19:  I  /  C 0  rg'  F e  sediment  /  A 1  a  n  d  core  M  n  p r o f i l e s of the hemipelagic  (HUD  22) r a i s e d from a  2768 m a t 20°53.6' N, Pedersen e t a l .  116  f  1986).  lO^l^.B  1  depth  W ( a l l data  of from  experiment  was  done  on a bulk  surface  sample.  Its  relevant  chemical c h a r a c t e r i s t i c s are shown i n Table 22. 3.4.1.1  OXYHYDROXIDES.  During the r e a c t i o n of the sediment IO^  released  from  reduced to I , react  with  necessary  the oxyhydroxide  possibly via I  sedimentary  1953a)  be  compounds.  It  and  should  of  any  readily  was  could  therefore released  T h i s was done by adding r e s o r c i n o l t o  solution.  for e l e c t r o p h i l i c  addition  would  to check the p o s s i b l e r e - a d s o r p t i o n of i o d i n e  hydroxylamine  affinity  phase  or HOI i n t e r m e d i a t e s , which  organic  during the r e d u c t i o n s t e p . the  2  with hydroxylamine,  T h i s compound has  iodine  a  (e.g. Fawcett  compete s u c c e s s f u l l y with  i o d i n e on sedimentary o r g a n i c  very and  an  strong  Kirkwood,  electrophilic  matter.  If  such  a  r e a c t i o n was o c c u r r i n g to any s i g n i f i c a n t e x t e n t , the presence of a  large  excess  of  r e s o r c i n o l should l a r g e l y  comparatively  more i o d i n e should be e x t r a c t e d .  electrophilic  iodine species  formation  soluble  of  hydroxylamine  could also  iodinated  extract.  inhibit  i t and  The presence  of  be  confirmed  by  resorcinol  compounds  i n the  The s t a b i l i t y of these compounds  the  i n the  a c i d i c / r e d u c i n g s o l u t i o n was checked over a p e r i o d of 6 h by t h i n l a y e r chromatography.  No sign of decomposition was observed over  this  the  period.  hydroxylamine centrifuged, thin  When in and  the  sediment  presence of  sample 80  was  ;umol/l  treated of  resorcinol,  the supernatant e x t r a c t e d with e t h y l  l a y e r chromatography  of the e t h y l a c e t a t e e x t r a c t 1 17  with  acetate, f a i l e d to  Table of  22: Chemical HUD  22  composition  (bulk  surface  sample).  C  org  (  %  1 .61+0.02  )  I (ppm) ^org  470+18 ( 1 0  "  4 )  292+12  Fe  (%)  6.87+0.06  Mn  (%)  0.62+0.01  118  show the presence of i o d i n a t e d r e s o r c i n o l thereby the  reduction  minimal. of  iodate  Moreover,  iodine  into  an  electrophilic  species  was  there were no d i f f e r e n c e s between the amount  extracted  (0.5 mole/1) that  of  i n d i c a t i n g that  either  or without  i n the presence of a  resorcinol  reduction/re-adsorption  (Table 23),  of  released  large  thus  excess  confirming  iodate  was  not  important. Table  23  sedimentary treatment.  also iodine  I f we  shows is  that  only  13  r e l e a s e d by the  assume that a l l the  +  5%  combined  of  the  acid-reducing  iodine released during  treatment comes from the s o l u b i l i z e d oxyhydroxide phase, be  shown that the  been  ~3500 ppm.  only  from  labile  concentration  with  importance  matter.  for  their  Therefore,  scavenging  although  abilities  for  comes  the  from iodine  high,  iodate  in  (e.g.  1958), t h i s phase seems to be only of secondary the  surficial  iodine  enrichment  sediments in the e a s t e r n S u b t r o p i c a l have  a well-developed  Since  oxide  layer  19) and do not c o n t a i n very high c o n c e n t r a t i o n s may  be a p p l i c a b l e to a wide  sediments.  119  in  Pacific.  (Fig.  conclusion  surficial  found  sediments  this  can  released  these  matter,  it  known i f t h i s i o d i n e  in the oxyhydroxides c o u l d be r e l a t i v e l y  Sugawara et a l . ,  hemipelagic  i t i s not  this  i n t h i s phase should have  the oxyhydroxide phase or i f some was  organic  accordance  iodine concentration However,  total  of  organic  range  of  Table 23: iodine  Influence of r e s o r c i n o l on the e x t r a c t i o n  from HUD 22 by hydroxylamine  hydrochloride.  Sediment Residue I (ppm) Without  resorcinol  In the presence of r e s o r c i n o l (0.5 mol/1)  of  Extracted I (ppm)* Fe (%)  Mn(%)  410+16  60+24  0.53  0.53  409+16  61+24  0.59  0.49  * Estimated by d i f f e r e n c e .  120  3.4.1.2 HUMIC SUBSTANCES. The  importance of the o r g a n i c f r a c t i o n was  examining  the  extraction sediment  of  the  sample  because  substances from  the  the  Therefore, sediment  sediment.  The  same  humic substances c o u l d not be  done  on  from which the oxyhydroxides had  been  removed  estimation  this  of the amount  e x t r a c t i o n was  sub-sample.  of  humic  of  acid  carbon  extracted. untreated  The r e s u l t s are shown i n Table 24. The  substances  was  very s i m i l a r  residue  Although  some of the iodate adsorbed on  a f t e r hydroxylamine  to  treatment  that (255  r e s u l t s would seem to i n d i c a t e  matter  s t u d i e d here,  x  this  iodine  the  10 ) . 4  the oxyhydroxide  phase these  that i n the s u r f i c i a l hemipelagic  i o d i n e i s mainly a s s o c i a t e d with  which c o u l d c o n t a i n as much as 1.25%  Moreover,  I/C  of  a l s o have been desorbed by the a l k a l i n e treatment,  sediment  the  rendered  performed on a second  sediment  could  by  the presence of hydroxylamine and a c e t i c  difficult  ratio  humic  investigated  seems to be roughly  throughout the h u m i f i e d m a t e r i a l s  by weight of evenly  organic iodine.  distributed  ( s o l u b l e or not i n NaOH). These  f i n d i n g s are c o n s i s t e n t with the data presented by Harvey  (1980)  who  marine  showed  sediment  that  samples  80% to 90%  of the i o d i n e  however,  not  upon  any  d i s c r e p a n c y may  in  c o u l d be r e l e a s e d by a 5% NaOCl treatment.  r e s u l t s of the two s t u d i e s d i v e r g e , find  present  release be due  of  iodine  NaOH  i n that Harvey d i d treatment.  to the short e x t r a c t i o n time ( i h ) used  t h i s author. 121  The  This by  Table 24: E x t r a c t i o n (duplicates) Sediment  of  iodine  from HUD  Residue  ^org (%)  I(ppm)  1.10 + .02 1.10 + .02  314+12 309+12  i/C  Amount (10~ ) 4  org  22  285+12 281+12  C  by  I(ppm)  0.56 + .01 0.63 + .01  1 40 + 6 1 54 + 6  122  NaOH  Extracted  (%)  org  0.5N  250+10 244+10  3.4.2  ASSOCIATION  BETWEEN HUMIC SUBSTANCES  AND  IODINE  DURING  EARLY DIAGENESIS. Further substances iodine  a  in particular,  f r a c t i o n during early sediment core  depth of 190m i n Hastings Arm, B r i t i s h Columbia.  are given by Losher  iodine  with  humic  the mechanism of the r e l e a s e of  by studying a nearshore  northern core  and,  of the a s s o c i a t i o n of  from t h i s organic  obtained from  details  diagenesis (HA-2)  recovered  a f j o r d on the coast  D e t a i l s of the geochemistry  (1985),  were  of  of this  some of which are i n c l u d e d  in  F i g . 20 and 21. The  pore  water  da.ta show that  manganese  was  dissolving  w i t h i n the top 3 cm, and a s u r f i c i a l enrichment of Mn was seen i n the s o l i d phase ( F i g . 21).  T h i s core was t h e r e f o r e o x i c only  the sea water/sediment i n t e r f a c e and became very r a p i d l y below.  Also,  the sulphur p r o f i l e  i n the bulk sediment  i n d i c a t e s that t h i s element was accumulating even 30  though H S 2  microenvironments mixing  peak  at  lower  I/C  ( F i g . 21)  w i t h i n the top 10 cm  r e f l e c t s the presence of  w i t h i n the suboxic  zone (Jorgensen,  with depth w i t h i n the upper 25 cm due to an e r r a t i c  The I/C r a t i o s  123  of  humic  anoxic  iodine  ( F i g . 20); input  as i n d i c a t e d by s u b s t a n t i a l l y higher ratios.  below  1977) and  Both organic carbon and t o t a l  40-45 cm was probably  t e r r e s t r i a l debris, and  T h i s probably  due t o b i o t u r b a t i o n .  g r a d u a l l y decreased the  reducing  s t a r t e d t o accumulate i n pore waters only  cm ( F i g . 21).  at  of  C g/N or  materials  20:  Sediment  core HA-2:  ratio profiles (b)  I  /  c o  r  g  (a) Iodine carbon and  (C and N data from  ratios  substances.  124  i n sediment  Losher,  C  Q r g  /N  1985).  and e x t r a c t e d humic  Fig.  Mn (ppm)  Mn (u.mol/1)  S(%)  H S (Mmol/1) 2  21: Sediment core HA-2:  (a) S o l i d phase - Mn (ppm) and S 2+  (%)  profiles.  (umol/1) p r o f i l e s  (b) pore  waters  - Mn  and  ( a l l data from Losher, 1 9 8 5 ) .  125  H S 2  closely thus  p a r a l l e l the I/C  confirming  surficial to  the  22 samples,  NaOH under the chosen I/C  higher  of humic  terrestrial  preferentially left  substances  i s that the humic substances  in  the  soluble  in  experimental c o n d i t i o n s have a c o n s i s t e n t l y  of  fraction,  ( F i g . 20),  A notable d i f f e r e n c e here, compared  r a t i o than the bulk sediment.  solubility  3.4.3.  involvement  i o d i n e enrichment.  the HUD  higher  r a t i o s of the bulk sediment  T h i s may  plankton-derived  materials  reflect  the  while  the  mainly composed of woody t i s s u e s , would be  i n the i n s o l u b l e  fraction.  EXPERIMENTAL STUDY OF THE UPTAKE AND  RELEASE OF IODINE BY  SEDIMENTARY HUMIC MATERIALS. The o b s e r v a t i o n s made i n the f i r s t that  p a r t of t h i s chapter show  i o d i n e i s indeed a s s o c i a t e d with the o r g a n i c f r a c t i o n  different  types of marine sediments,  possibly  play  and that humic  an important r o l e i n f i x i n g  iodine  i n two  substances  in  surficial  sediments. In a d d i t i o n , organic 1972;  matter Mango,  molecules  or  nucleophilic  s u l p h i d e anions are thought  to r e a c t with  d u r i n g e a r l y d i a g e n e s i s (Nissenbaum and 1983;  Chap. 2). T h e r e f o r e , i f i o d i n a t e d  other  forms  of  organic  displacement are present,  iodine  the  Kaplan, aliphatic  susceptible  to  the p r e f e r e n t i a l r e l e a s e  of i o d i n e from the humic matrix at depth c o u l d be the r e s u l t of a reaction similar to:  126  A/ Displacement problematic sulphidic  of  zones  by  HS  p l a y an  important  reduction within  present  horizons.  and  i s known to occur  anoxic  transient  microenvironments  and  (e.g.  even  Jorgensen,  s o l u b l e sulphur compounds c o u l d  species  in  near-surface  sediment  sediments  must have been o x i d i z e d a f t e r t r a n s f e r  cannot  of  these  of r e l a t i v e l y sulphur and  sediments (e.g.  enrichment  in  l a r g e c o n c e n t r a t i o n s of  to  T h i s should  also  compounds.  shown  by  reduced i n the  where a s i g n i f i c a n t (see  2  Boulegue et a l . ,  (Chen and M o r r i s , 1972;  suboxic sulphur-  Chap.  1982).  Jorgensen  the  sulphur  i s such a t r a n s i e n t s p e c i e s which can be  by the o x i d a t i o n of H S  be  more  s u l p h i d e s ) g e n e r a l l y found F i g . 21),  2  the  is clearly  the humic m a t e r i a l s a l s o occurs  Thiosulphate  to  processes  HS  (Jorgensen,  a s i g n i f i c a n t amount of intermediate sulphur  (elemental  ability  somewhat  i n suboxic  l a y e r s by d i f f u s i o n or b i o t u r b a t i o n .  presence  1979;  is  by the s u l p h i d e p r e c i p i t a t e d t h e r e i n  importance  zone of  however,  role.  the anoxic zone of nearshore  for  oxidized  The  as  in  accounted  produce  (5)  Moreover, i t has been argued that 80 to 95% of the  produced  1982)  ,  + I  I/C  1977), so that p a r t i a l l y - o x i d i z e d be  A /-Nu  —>  r a t i o u s u a l l y decreases before the org of the sediment i s reached. Therefore, other  zone  Sulphate  + :Nu" iodine  since the  n u c l e o p h i l e s may  oxic  1  2).  formed et a l . ,  I t i s a strong n u c l e o p h i l e whose  d i s p l a c e i o d i n e from i t s a l k y l d e r i v a t i v e s  127  is  well  known ( M i l l i g a n and Swan, 1962), v i z 0 > R-S-SJ-ONa + Na  R-I + Na SS0, 9  +1  6  (6)  which slowly h y d r o l y z e s to form a t h i o l , v i z  R-S-I-ONa + H„0 Reaction  +  (6) i s known to be q u i t e r a p i d even at room  (Slator, range  > R-S-H + HSO ~ + Na (7)  1905)  and  to proceed at c o n c e n t r a t i o n s i n the 100  (Trudinger,  concentrations  temperature  1965;  Roy  and  Trudinger,  1970).  Such  have a l r e a d y been measured i n the pore waters  anoxic s u b t i d a l and s a l t marsh sediments  (Boulegue et a l . ,  Luther  some experiments on  et  a l . , 1985).  adsorption release this  of  I  by  Consequently,  humic substances  and  were c a r r i e d out to i n v e s t i g a t e  purpose,  collected  on  these  humic a c i d s e x t r a c t e d from  its  uM  of  1982; the  subsequent  reactions.  bulk sediment  For  samples  from J e r v i s I n l e t were used f o r a l l experiments.  3.4.3.1 UPTAKE OF IODINE BY HUMIC MATERIALS. Sedimentary humic a c i d s were d i s p e r s e d spiked  with e i t h e r  neutralized obtained, conditions, acids  and  iodate or i o d i d e .  were  presented iodate  The d i s p e r s i o n s  therefore s l i g h t l y in  Table  in f i l t e r e d  25,  acidic.  show  that,  sea water were  The under  not  results these  can react to a s u b s t a n t i a l extent with humic  while i o d i d e does not produce any 128  measurable  enrichment.  Table  25:  Uptake  of  iodine  by  marine  sedimentary humic substances. C(%)  I ( % ) I/C(10 )  I n i t i a l composition  49. 3  0 .29  60 + 3  + 1 mmol/1 KI*  47. 3  0 .26  55 + 3  + 1 mmol/1 KIO *  46. 3  1 .06  229 + 7  4  * Humic substances were d i s p e r s e d i n 100 ml of spiked, f i l t e r e d seawater f o r 4 days, under oxygenated c o n d i t i o n s .  1 29  The  r e a c t i o n between iodate and humic m a t e r i a l s was then  under  environmental  pH c o n d i t i o n s .  humic  substances ,  brought to pH 8,  left  A solution  of  sedimentary  was spiked with  iodate and  f o r 5 days (during t h i s p e r i o d the pH dropped to  shown  i n Table  the  26,  i o d i n e content  these  materials  7.4). As  t h i s treatment a l s o s i g n i f i c a n t l y of the humic m a t e r i a l ,  could  be  involved  tested  increased  thus suggesting  i n the  that  iodine-enrichment  observed i n s u r f i c i a l o x i c marine sediments. 3.4.3.2  INVESTIGATION OF THE MECHANISM OF IODINE UPTAKE BY HUMIC  MATERIALS. The  reducing  established Szilagyi, Wilson  (e.g.  of  Szil&gyi,  1967;  1967; A l b e r t s et a l . ,  and Weber,  Brezonic, possibly  properties  1981;  Sunda et a l . ,  i o d i n e which i s unstable  hydrolyzes  and produces h y p o i o d i t e  organic  water pH, h y p o i o d i t e  and  ) .  1973;  consequently  order  Szalay  and  matter  i n seawater. (Truesdale, (Wong,  ,they  could  of t h i s r e d u c t i o n i s It either reacts 1974;  1980;  1982) or  1982).  (HOI . H  a c i d has a strong e l e c t r o p h i l i c  a l s o r e a d i l y react with organic molecules  electron-donor  well  S c h n i d l e r et a l . , 1976;  i s e s s e n t i a l l y protonated  Hypoiodous  would  In  1974;  1983);  with  1  1971;  are  1979; Templeton and Chasteen, 1980; M i l e s and  directly  1  substances  reduce i o d a t e . One p o s s i b l e product  elemental  K=10  humic  At sea +  + 10  character possessing  groups. to v e r i f y t h i s hypothesis,  130  r e s o r c i n o l was  added  Table 26: marine  Uptake of i o d i n e by sedimentary  humic  substances at pH 7.4 - 8 I/COO" ) 4  Initial  composition  + 2.5 mmol/1 KIC> * 3  63+4 142 + 6  * Humic substances (0.3g) were d i s p e r s e d i n 100 ml of spiked, d i s t i l l e d water and brought to pH 8 f o r 5 days.  131  with  iodate  Resorcinol hydroxyl  to is  a s u b s t i t u t e d aromatic  groups  electron-donor to  d i s p e r s i o n s of f i n e l y ground  undergo  positions,  in  meta-position.  humic  compound  containing  two  groups i n c r e a s e s the tendency of the aromatic  ring  and  in  presence of  substitution  the presence of HOI  in  para-  or  it  i o d i n a t e d r e s o r c i n o l compounds (e.g. Fawcett and which  can  be  Therefore, is  by  the  readily  forms  Kirkwood, 1953a) (Table  r e d u c t i o n / e l e c t r o p h i l i c attack  the presence of r e s o r c i n o l should  the e l e c t r o p h i l i c a d d i t i o n on humics, and information resorcinol  could in  electrophilic iodine  responsible  the  be  obtained.  enrichment would  The  two  27).  iodate  mechanism  compete  with  important p i e c e s  presence  r e a c t i o n medium would  i o d i n e s p e c i e s has  competition,  Since  ortho-  i f the i o d i n e enrichment of humic substances by  p o s t u l a t e d above,  the  and  i d e n t i f i e d by t h i n - l a y e r chromatography  mediated  two  these  electrophilic  The  materials.  of  iodinated  demonstrate  been produced, and  of humic m a t e r i a l s ,  due  of  that  an  a decrease of to  resorcinol  i n d i c a t e that such e l e c t r o p h i l i c  attack  is  f o r the enrichment. the  r e d u c t i o n of one  iodate ion consumes 6  protons,  viz I0 ~  + 5e~  + 6H  +  IO,~ 3  + 6e~  + 6H  +  3  this  1 2 + 3H 0  ?=^  1/2  ^=a  I~ + 3H„0 2  2  ion w i l l be more s t r o n g l y o x i d i z i n g at low  132  E  Q  O  =  1.23V  =  1.08V  pH.  Therefore,  T a b l e 27: v a l u e s of r e s o r c i n o l and i t s iodinated derivatives during Thin Layer Chromatography on Si0 w i t h 80% C H C l / 2 0 % C H C O O C H C H . 2  Compounds  3  1  3  Rf  2  2  Mol.  wt.  3  3  Rf  (resor.)  resorc inol  -0.18  1 10  -0.18  mono-iodinated resorc i n o l di-iodinated resorc i n o l tri-iodinated resorc inol tri-iodinated resorc i n o l  -0.25  236  -0.25  -0.48  362  -0.48  -0.56  488  -0.56  -0.61  488  1 - Prepared by reaction between r e s o r c i n o l i n aqueous s o l u t i o n . 2 - Rj = (distance compound)/(distance of front).  iodine  4  and  of travel of the travel of the solvent  3 - Molecular w e i g h t of t h e isolated d e t e r m i n e d by mass s p e c t r o m e t r y .  compounds  4 - Rf of the compounds produced during reduction of iodate by humic materials in p r e s e n c e of r e s o r c i n o l .  133  the the  the  reduction  dispersed  was  first  water at pH  tested  with  humic  r e s o r c i n o l compounds (mainly  some d i - and  acetate  tri-iodinated  27  and  mono-iodinated,  but  forms) were found in  e x t r a c t of the h u m i c / i o d a t e / r e s o r c i n o l  indicating  that  iodate was  acids  2.5-3.0.  r e s u l t s of t h i s experiment are shown i n Tables  Iodinated  also  iodate  in d i s t i l l e d  The 28.  of  reduced to an  the  ethyl  dispersion,  electrophilic  thus iodine  s p e c i e s . A l s o , the s i g n i f i c a n t decrease of i o d i n e a d d i t i o n to humic  matrix  that  electrophilic  responsible also with  when r e s o r c i n o l was  f o r the  performed 2.5  addition  present  of  this  i o d i n e enrichment.  (Table reduced  The  confirmed  species  was  same experiment  at a lower iodate c o n c e n t r a t i o n  mmol/1 r e s o r c i n o l ) .  28)  (10  the  was  >umol/l  Although much more d i f f i c u l t  10^  to  see  on the chromatographic p l a t e , t r a c e s of mono-iodinated r e s o r c i n o l were  a l s o evident  isolate mmol/1  a f t e r 24 h shaking  i n the dark.  In  to  i o d i n a t e d r e s o r c i n o l o c c u r r i n g at a few jjmol/1 from resorcinol,  it  was  necessary to do the s e p a r a t i o n  preparative  plate.  concentrated  in the upper part of the r e s o r c i n o l band.  of  order  the  acetate.  plate  was  I-resorcinol  was  carefully collected  T h i s e l u a t e was  not  and  separated  eluted  then re-chromatographed and  2.5 on  but  a was  This part with  ethyl  a faint  but  unambiguous t r a c e of mono-iodinated r e s o r c i n o l appeared on top of the  still  prominent r e s o r c i n o l spot.  Polyhydroxyphenols  are  r e s p o n s i b l e f o r the reducing  thought to be,  in  part,  p r o p e r t i e s of humic m a t e r i a l s  (e.g.  134  at l e a s t  Table  28:  resorcinol substances  Initial + 2.5  Influence on at  the pH  m m o l / 1 KIC> *  * Humic 10 m l o f  iodine  the  presence  uptake  by  of  humic  2.5-3.  composition 3  + 2 . 5 mmol/1 KIO and 2.5 mmol/1 resorc inol  of  *  C(%)  K%)  I/COO  40.6  0.54  132+7  38.8  1.51  389+13  40.9  0.97  294+9  4  )  s u b s t a n c e s ( 0 . 2 g ) were d i s p e r s e d in s p i k e d , d i s t i l l e d w a t e r f o r 24 h r s .  135  Templeton bring  and Chasteen,  1980).  Thus,  resorcinol itself  could  about the r e d u c t i o n of iodate with subsequent formation  iodinated presence  resorcinol.  However,  when iodate i s reduced  of both humic m a t e r i a l and  iodinated  r e s o r c i n o l at low pH,  mono-  hour of  reaction,  the absence of humic substances,  i t took  24  in  observe  the f i r s t appearance of i o d i n a t e d r e s o r c i n o l  h  reduction  which  occurred  confirmed  by  independent t e s t  an  iodate was  in the previous  experiment.  in which  a  to  compounds.  humic m a t e r i a l s are r e s p o n s i b l e f o r most of the  spiked with  the  r e s o r c i n o l i s d e t e c t a b l e w i t h i n one  whereas  Clearly,  in  of  iodate  This  humic  was  dispersion  v i g o r o u s l y mixed with benzene.  Within  two  hours, a pink c o l o r a t i o n c o u l d be seen i n the benzene phase which was  identified  500 mn;  Benesi  For  as  i o d i n e by i t s a b s o r p t i o n  and H i l d e b r a n d ,  the  above  reducing 1973;  to be  and Weber,  any  consumption  of  protons  increasingly d i f f i c u l t potential  drops from 1.23V potential 1.08V  of  during  However,  =  for  iodate  reduction,  to 0.75V between pH  0 and  of  it  Eh at pH 136  The  iodine  the redox  iodide  0 of humic m a t e r i a l s  the  becomes  and  8. Likewise,  an equimolar s o l u t i o n of iodate and  The  to the  to reduce iodate as the-pH i n c r e a s e s .  The  x  (Szilagyi,  because  of an equimolar s o l u t i o n .of iodate  to 0.6V.  a  consequence  1979). T h i s i s thought to be due  of semiquinone r a d i c a l s .  from  of  power of humic substances i n c r e a s e s with pH  Wilson  m  i t must a l s o occur at higher pH.  involvement  redox  (A  1949).  mechanism  environmental geochemistry,  spectrum  in  falls water  has  been estimated  humic  acids;  to be 0.5V  Szilagyi,  derived f u l v i c acids; values as being  1973)  at  t y p i c a l of humified  pH8,  the  thermodynamically Consequently,  and  0.7V  case  reduction  possible  of  under  was  resorcinol  attempts  compounds  sensitivity  of  the  i t f o l l o w s that  failed.  still  the  T h i s may  technique used.  7.5  - 8. of  be due  the  to  showing  However, in  formation  The  iodinated lack  electrophilic  produced by the r e d u c t i o n of iodate  i s a transient species  concentration  its  consumption. and  is  As the pH  therefore  Consequently, formed,  and  determined  its much  by  rate  of  be  conditions.  used as a means of at pH  as  lower than  would  environmental  again  to show  iodate  soil-  take these  i n c r e a s i n g pH to reach values  resorcinol  all  1979). I f we  materials,  that the r e d u c t i o n of iodate occurred this  peat-derived  ( f o r a s o l u t i o n of  Wilson and Weber,  t h e i r Eh decreases with 0.5V  ( f o r a d i s p e r s i o n of  of  iodine whose  formation  and  increases,  the r a t e of iodate  reduction,  steady-state  concentration,  decreases.  less  i o d i n a t e d r e s o r c i n o l compounds can  i t becomes i n c r e a s i n g l y d i f f i c u l t  to separate  be them  from a much more abundant r e s o r c i n o l p o o l . In  conclusion,  although the  substances at n e u t r a l pH has i t has  been shown that iodate  materials whereby  at pH values iodine  is  not  r e d u c t i o n of iodate  humic  been unambiguously demonstrated,  i s able to e n r i c h sedimentary humic  c l o s e to those of sea water.  added  by  to  humic  1 37  materials  A mechanism  under  acidic  conditions suggest  has been demonstrated. that  this  mechanism  c o n d i t i o n s ; however, c o n f i r m a t i o n  Thermodynamic still  occurs  isstill  considerations under  natural  required.  3.4.3.3 RELEASE OF IODINE FROM HUMIC MATERIALS. The  displacement experiments were performed by d i s p e r s i n g I -  enriched  humic  sulphide  and t h i o s u l p h a t e .  after  materials  i n oxygen-free I/C r a t i o s  seawater  spiked  with  i n the humics before  and  treatment are shown i n F i g . 22. I t can be seen that a l a r g e  fraction during  of the i o d i n e added d u r i n g  the S treatments.  the iodate treatment was l o s t  Hence, i o d i n e i s e v i d e n t l y d i s p l a c e d by  these s p e c i e s and such r e a c t i o n s c o u l d occur i n sediments. The  results  significant pH  3.4  acidic  proportion  can  suggests  presented  i n F i g . 22  show  that  a  of the i o d i n e added by iodate r e d u c t i o n a t  be d i s p l a c e d by sea water  that  also  some of the organic  alone  iodine  s o l u t i o n s are very p H - s e n s i t i v e  (pH  7.6), which  compounds  formed  and decompose at  in  neutral  pH. Subsequently, enriched easily  humic m a t e r i a l was a l s o t e s t e d . displaced  nucleophile  alkaline Table  by  itself,  displacement  in  the displacement of i o d i n e from a n a t u r a l l y -  from  extraction. 29  nucleophiles, to  be  able  I f excess i o d i n e can be  one to  the humic m a t e r i a l s  would  expect  contribute  to  solubilized  of  found i n the NaOH e x t r a c t of HUD 22 sediments was not 138  the  during  T h i s was confirmed by the r e s u l t s  which show that a l a r g e p r o p o r t i o n  OH , a Ithe  presented  the  iodine  associated  300.  i  200 _  o  o  100  (a)  0 J  (1) Fig.  22:  (2)  (b) (3)  (c)  (1)  (4)  (5)  humic D i s p l a c e m e n t of i o d i n e from I - e n r i c h e d substances: (1) I n i t i a l I/C r a t i o . (2) Humic s u b s t a n c e s (0.2 g) were d i s p e r s e d i n 50 ml i o d a t e s o l u t i o n (2.5 mmol/1; pH 3.4) f o r 18 h. (3) I - e n r i c h e d humic m a t e r i a l s from (2) were dispersed i n : (a) Seawater (pH 7.6; 52 h ) . (b) Seawater + 5 mmol/1 t h i o s u l p h a t e (pH 6.9; 52 h ) . (c) Seawater + 15 mmol/1 s u l p h i d e (pH 8.0; 52 h ) . (4) Humic s u b s t a n c e s (0.3 g) were d i s p e r s e d i n 100 ml i o d a t e s o l u t i o n (2.5 mmol/1; pH 8.0) f o r 5 days. (5) I - e n r i c h e d humic m a t e r i a l s from (4) were dialysed i n 4 1 t h i o s u l p h a t e s o l u t i o n (5 mmol/1; pH 8.4) f o r 6 d a y s . 139  Table 29: iodine  Displacement  of  from humic m a t e r i a l s ,  e x t r a c t e d from HUD 22,by 0H~ and HS~.  I/COO ) 4  * Humic e x t r a c t  242+10 *  Humic e x t r a c t after dialysis  1 03+11  Humic e x t r a c t after sulphide treatment and dialysi s  89+7  * See method d e t a i l s on the procedure.  section for experimental  *  1 40  with  the  humic  displacement during  molecules.  of  this  This  i o d i n e f r a c t i o n from the  the NaOH e x t r a c t i o n .  nucleophilic  attack  marine sediment  i s presumably  on  the excess  iodine  organic  found  o c c u r s . I t i s a l s o noteworthy 2  r a t i o measured i n the deeper  the core s t u d i e d e a r l i e r  to the matrix  T h i s shows the r e a d i n e s s with which  o b t a i n e d a f t e r d i a l y s i s and H S treatment I/C  due  in  surficial  that the I/C r a t i o  i s very s i m i l a r t o the  p a r t of the sediment  column  in  ( F i g . 19).  3.5 CONCLUSION.  The  r e s u l t s obtained from the chemical l e a c h i n g experiments  indicate iodine  that,  i n the s u r f i c i a l  i s mainly  oxyhydroxides From  associated  are  the  only  of  experimental  concluded that the s u r f i c i a l under  oxygenated  part,  of  the  species  by  substitution Michel, molecules would  humic  1951;  also  sediments,  with  organic  secondary data  of  iodate  materials,  here,  containing  at  1953a;  e l e c t r o n - d o n o r groups.  by  least  in  iodine  electrophilic 1947;  Roche and  1953b) on organic Such  e x p l a i n the absence of i o d i n e enrichment since iodide,  be  deposited  to . e l e c t r o p h i l i c  followed  and Kirkwood,  i t can  of sediments  O l c o t t and F r a e n k e l - C o n r a t ,  Fawcett  while  importance.  presented  I-enrichment  analyzed,  matter,  c o n d i t i o n s c o u l d be the r e s u l t ,  reduction  (e.g.  hemipelagic sediment  a  mechanism in  anoxic  which i s the main i o d i n e s p e c i e s found 141  in anoxic environments 1979),  does  not  environmental assessed, and  HOI  (Wong and Brewer,  react  with  significance  humic  1977;  Emerson et a l . ,  substances.  However,  of t h i s mechanism s t i l l  needs to  and a l t e r n a t i v e e x p l a n a t i o n s cannot be r u l e d can a l s o be produced by other mechanisms.  It  out. has  the be I  2  been  suggested that the i o d i n e enrichment i n s u r f i c i a l  sediments c o u l d  be  thought  mediated  associated cells I  2  by  an  enzyme  (iodide  oxidase)  with the i n i t i a l degradation products  ( P r i c e and C a l v e r t ,  1973).  of  planktonic  (Shaw, 1959,  Since  this  could  a l s o e x p l a i n the c o n t r a s t i n g behaviour of i o d i n e  marine be  r e a c t i o n occurs only i n the presence of  to  o x i d i z e a s i g n i f i c a n t amount of  (Gozlan,  1968;  isolated  from  oxidation  2  1973).  Although  marine sediments,  could  considered. I  ( P r i c e and C a l v e r t ,  oxygen, in  1977). A l s o ,  be  such the  bacterially  iodide  oxic  mediated  Moreover, Tsunogai and Sase  that  should  reductase,  an  assimilation  enzyme and  in  been iodide  also  be  (1969) demonstrated  that  present i n a e r o b i c organisms f o r dissimilatory  nitrate  reducers.  nitrate nitrate Nitrate  are present i n many marine sediments and t h e r e f o r e  have a s i g n i f i c a n t  impact on i o d i n e geochemistry. F i n a l l y ,  1 42  to  iodine  organisms have not possibility  it  certain  to  c o u l d a l s o be produced by the r e d u c t i o n of iodate by  reducers  1962).  aerobes i s o l a t e d from a sea water aquarium were shown  able  be  T h i s enzyme o x i d i z e s i o d i d e to  which h y d r o l y s e s and forms hypoiodous a c i d  and anoxic environments  to  may  i t was  also  shown that molecular  i o d i n e c o u l d be produced  r e d u c t i o n of iodate by HS reaction  could  possibly  microenvironments, the  surface  possibility. reduction common HOI)  All  of  occur  and W h i t f i e l d ,  at  the  The  (e.g.  these processes  iodate and  interface  Chap.  (i.e.  of  anoxic  sulphur  in  supports  chemical  of an e l e c t r o p h i l i c  relative  2)  within  or  this  enzymatic  enzymatic o x i d a t i o n of i o d i d e ) have  able to react with organic matter. their  1986). Such  occurrence of elemental  sediments  the production  between  chemical  such as f r e s h l y egested f e c a l p e l l e t s ,  oxic surface l a y e r .  oxide-rich  (Jia-Zhong  by  importance  iodine species  However,  for  (I  2  in or  distinguishing  iodine  enrichment  in  s u r f i c i a l o x i c sediments r e q u i r e s f u r t h e r i n v e s t i g a t i o n . The marine  decreasing  I/C  sediments d e p o s i t e d  preferential  release  iodine  a  with  on  substances  described  bacterial  the  to  sediments. and  labile  r e l e a s e of here  decomposition  necessary  HS  but  been suggested  experiments  decrease  burial,  characteristic  under a e r o b i c c o n d i t i o n s ,  of i o d i n e at  major  organic matter has  as  r a t i o with  of  depth.  The  fraction  of  ( P r i c e and iodine  the  I-bearing  significantly  -  the I/C  e a s i l y d i s p l a c e excess  substances. Such sulphur  s p e c i e s , i f present  c o u l d p o s s i b l y e x p l a i n the p r o f i l e s 143  observed.  that  fraction ratio  These r e s u l t s suggest that n u c l e o p h i l e ^O^  1977).  I-enriched  however  iodine  of  sedimentary  Calvert,  from  demonstrate  requires a  association the  of  The  humic direct  is of  species, from  in the suboxic  not buried such humic zone,  Iodine complexes)  can a l s o form weakly-bound molecular complexes with many o r g a n i c molecules (e.g.  Benesi and H i l d e b r a n d , 1950).  The  iodide  (e.g.  be  released  iodine  1949;  Fairbrother,  H i l d e b r a n d et a l . ,  from these complexes  Fawcett and Kirkwood,  2  + 2e~  i s readily  iodine  reduced  to  1953a), and c o u l d c o n c e i v a b l y  =^  dropped  2I~, E° = 540 mV), without  r e q u i r i n g the need f o r a n u c l e o p h i l i c displacement. relative  1947;  1950; M u l l i k e n ,  from the organic matrix as soon as the  below ~500 mV (assuming: I  (T) -  However, the  i n e f f i c i e n c y of hydroxylamine h y d r o c h l o r i d e i n removing from HUD 22 s u r f a c e sediment argues a g a i n s t the  presence  of such compounds i n any l a r g e amount. The 10-15% of i o d i n e which was s o l u b i l i z e d by t h i s reducing treatment c o u l d have come p a r t l y from such a source and not only from the oxyhydroxide phase. above  figure  must  t h e r e f o r e represent the  maximum  amount  i o d i n e a s s o c i a t e d with that part of the oxyhydroxide phase was s o l u b i l i z e d .  144  The of  which  4.  A STUDY OF THE REGULATION OF METAL CONCENTRATION IN SAANICH INLET SEDIMENTS.  4.1 INTRODUCTION  An  enrichment  sediments observed 1970; also  in  deposited (Krauskopf,  1983; C a l v e r t , tend  to  (Richards,  be  under  anoxic  1955;  Manheim,  1970),  and a s t a t i s t i c a l  between Brumsack,  organic  1976;  has  1970;  et  been reported  al.,1986).  further  and metals support  (Volkov  adequate  organic (Curtis,  such  association  Fomina,  f o r the occurrence  been obtained from the extracted  matter  While  and  analysis  1974;  of  of  from anoxic sediments which i n the  such  various showed humic  (Volkov and Fomina, . 1972; Nissenbaum and Swaine, 1976;  C a l v e r t and M o r r i s , The  Price,  Volkov and Fomina, 1972;  r e l a t i v e l y high metal c o n c e n t r a t i o n s , • p a r t i c u l a r l y fractions  been  organic  matter  fractions  often  c o r r e l a t i o n between  1983;  Rosental  of  direct  has  fine-grained  C a l v e r t and  not n e c e s s a r i l y i n d i c a t e a  1980),  associations organic  do  1961;  t r a c e metals has o f t e n  Calvert,  correlations  conditions  in  1976; Jacobs e t a l . , 1985). These sediments  C a l v e r t and P r i c e ,  1974;  t r a c e elements  have high c o n c e n t r a t i o n s  carbon and v a r i o u s 1966;  various  mechanism supply  1977; C a l v e r t et a l . , 1985). f o r these enrichments i s s t i l l  of metals and d i a g e n e t i c 1 45  processes  obscure.  An  leading  to  t h e i r accumulation i n the e n r i c h e d sediments are r e q u i r e d . Marine plankton i s the most o f t e n c i t e d source of metals . has  been  argued  that the  metal  concentration  However, in  it  planktonic  m a t e r i a l s i s not high enough to account f o r the metal enrichments observed i n sediments (e.g. water column  Brumsack, 1980). Scavenging from the  (Volkov and Fomina,  1972;  1974) or p o s t - d e p o s i t i o n a l  metal enrichment i n the d e p o s i t e d organic matter v i a l e a c h i n g the  m i n e r a l o g i c a l components of the sediment by humic  (Nissenbaum et  and Swaine,  C a l v e r t and M o r r i s ,  a l . , 1985) has been suggested.  precipitation has  also  1965; and  1976;  of  been proposed  Piper,  (Krauskopf,  1971; B e r t i n e ,  Spencer,  1974;  materials  1977;  Calvert  D i r e c t p r e c i p i t a t i o n or  metal s u l p h i d e s from s u l p h i d i c 1956;  water  co-  columns  Brongersma-Sanders,  1972; Volkov and Fomina,  Jacobs and Emerson,  of  1982;  1974;  Brewer  Jacobs et a l . ,  1985). It the  i s g e n e r a l l y accepted that w i t h i n the e n r i c h e d  excess metal i s a s s o c i a t e d e i t h e r with the organic phase  with  the  sulphide  phase.  Since  both  organic  s u l p h i d e m i n e r a l s are reduced c o n s t i t u e n t s of the is  sediments  difficult  oxidative various  to  leaching  distinguish  their  (Nissenbaum  and  relative Swaine,  sediments, importance 1976).  (Volkov and  and it by  Instead,  workers have attempted to separate p h y s i c a l l y these  phases, using bromoform f o r p y r i t e s e p a r a t i o n 1974),  materials  or  two  Fomina,  and d i s s o l u t i o n of the humic polymers i n NaOH f o r organic  1 46  matter  (Volkov and Fomina,  1972;  Nissenbaum and Swaine,  1976;  C a l v e r t and M o r r i s ,  there  are u n c e r t a i n t i e s with the i n t e r p r e t a t i o n of  particularly obtained  1977;  1974;  C a l v e r t et a l . ,  1985). Although these  from the humic e x t r a c t i o n experiments,  suggest  geochemical  that  balance  both of  phases  various  are  the r e s u l t s  significant  metals  in  data,  in  different  the  anoxic  sediments. Moreover, to  be  s i n c e sediments accumulating in anoxic b a s i n s tend  fine-grained,  and  since  such  texture  is  invariably  a s s o c i a t e d with higher organic matter content (Trask, Andel,  1964)  1980;  Salomons  and metal c o n c e n t r a t i o n s (Krauskopf, 1979; and F o r s t n e r ,  1983),  Fomina,  by  textural  and hydrodynamic  at l e a s t factors  metal  i n p a r t , be (Volkov  and  1974).  F u r t h e r i n v e s t i g a t i o n s of the c o n t r o l mechanisms the  Van  Ackerman,  organic carbon and  enrichments i n anoxic sediments c o u l d a l s o , controlled  1953;  distribution  studying  the  regulating  of metals i n anoxic b a s i n s were undertaken  metal  and  o r g a n i c carbon  distributions  in  by the  sediments of Saanich I n l e t , an i n t e r m i t t e n t l y anoxic f j o r d on the coast of B r i t i s h Two  complementary approaches were taken.  c o n s i s t e d of of  the  a comprehensive  sediments  processed groups  Columbia.  of  the  statistically  of elements.  in  a r e a l survey Inlet.  The  The f i r s t  approach  of the metal  content  results  an attempt to  obtained  identify  The second approach c o n s i s t e d of 147  were  co-varying analyzing  the s e t t l i n g p a r t i c u l a t e s recovered from sediment i n the water column over an 18 month p e r i o d . i n p a r t i c u l a t e f l u x e s and comparison and organic carbon accumulation sites  A metals  Seasonal  variations  r a t e s i n the sediment  at the t r a p  factors regulating  significant  trapped bearing  geochemical  in not  the  sediments.  b e t t e r a p p r e c i a t i o n of the mechanisms whereby are  deployed  of these data with the metal  was used to evaluate the d i f f e r e n t  metal c o n c e n t r a t i o n s i n these  traps  anoxic only  environments  on  c y c l e s of these elements  our  transition  would  understanding  (e.g. C a l v e r t ,  have of  a the  1976) and on  the formation of important ore d e p o s i t s (e.g. Brongersma-Sanders, 1965),  but  also  c o u l d p r o v i d e us  p o s s i b l e expansion An  of anoxic environments  i n c r e a s e i n the importance  dramatic elements  with a t o o l to  effect  on  the  of these environments  seawater  the  i n the g e o l o g i c a l p a s t . may  concentration  (e.g. molybdenum) which c o u l d p o s s i b l y be  i n the sedimentary  examine  of  have  a  certain  recognizable  r e c o r d (Emerson, p e r s . comm.).  4.2 GENERAL FEATURES OF SAANICH INLET AND SAMPLING  LOCATIONS  4.2.1 GENERAL DESCRIPTION Saanich south-east length,  7.2  Inlet  is  an i n t e r m i t t e n t l y anoxic  coast of Vancouver I s l a n d km  a t i t s widest p a r t , 148  (Fig.  23).  fjord  on  the  I t i s 25 km i n  and i s connected  to  Haro  149  Strait  in  Satellite  the  east and Georgia  Channel.  Water  r e s t r i c t e d by a w e l l - d e f i n e d , mouth of the i n l e t , t h i s shallower off  Strait  exchange  in  the  through  north-east  this  r e l a t i v e l y deep s i l l  channel  The  the f l o o r deepens to a maximum of 232 m  r i s e s r a p i d l y toward the Goldstream  drainage basin of the i n l e t  "rain-shadow",  so  that  River.  i s small and s i t u a t e d i n a  i t contributes  little  water  (Herlinveaux,  1962).  of t h e f j o r d ,  i s the l a r g e s t stream e n t e r i n g the i n l e t i s small  Most of the fresh-water  run-off  the Cowichan R i v e r ,  flowing  km north-west of the s i l l seasonal 3 " m /sec)  erratic  the  (Fig.  s i t u a t e d about 6  23). I t s d i s c h a r g e  follows  the  with a maximum i n December (~90 3 (5-10 m / s e c ) .  observed  over  short  However,  periods,  large  producing  T h i s f r e s h water input g e n e r a l l y i n f l u e n c e s only  m  of the water column,  pycnocline, The  i n t o Cowichan Bay,  f l u c t u a t i o n s i n the s u r f a c e s a l i n i t y at the entrance  inlet. 10  been  1962).  reaching' Saanich I n l e t comes from  and a minimum i n August have  directly;  (0.85 m /sec; Herlinveaux,  p r e c i p i t a t i o n pattern,  variations  run-off  The Goldstream R i v e r , s i t u a t e d at the head  however, i t s discharge  top  Beyond  Shepard P o i n t . I t shoals g r a d u a l l y toward S q u a l l y Reach (~180  m) and f i n a l l y  the  is  (~75 m) at the  between Moses Point and Hatch P o i n t .  entrance,  by  particularly  producing  a  sharp  maximum i n June.  the  sub-surface  i n winter.  s u r f a c e waters of Saanich I n l e t a r e a l s o i n f l u e n c e d  f r e s h water discharge  of  from the F r a s e r R i v e r ,  Each summer,  a low-salinity, 150  by  which i s at i t s s i l t - l a d e n water  mass  moves  towards the Gulf  through S a t e l l i t e Channel, generally  evident  Herlinveaux, This fjords the  down  to  50  major source  Inlet  a s u r f a c e d i l u t i o n which i s  m  depth  (Waldichuk,  1957;  of water r u n - o f f e n t e r s at the head  thus producing  1958).  mainly  a strong  In Saanich  very weak and sporadic  nearby  estuarine-type  circulation  (Herlinveaux,  1962;  1966;  1972) and i s  by the Cowichan water inflow which i n t r u d e s  Haro  Strait,  of  I n l e t , t h i s type of c i r c u l a t i o n seems  the i n l e t at ebbing t i d e s producing in  Saanich  p a t t e r n of f r e s h water input i s unusual s i n c e i n many  inlet,  driven  producing  enters  1962).  the  (Tully,  I s l a n d s and  thus  into  water of lower d e n s i t y  establishing  a  weak  than  estuarine  f l u s h i n g mechanism. Therefore, exchange  of  e s t u a r i n e and t i d a l  f l u s h i n g produce an e f f e c t i v e  s u r f a c e water with nearby  tidal  currents  where  the  diminish  The  although  r a p i d l y toward the head of  s u r f a c e water i s p a r t i a l l y  exchanged.  channels,  estuarine  i s o l a t e d and  circulation  is,  the  only  the inlet  slowly  however,  not  s u f f i c i e n t l y developed t o f l u s h the deep basin of the i n l e t below sill-level.  Consequently,  anoxia  gradually  e v e n t u a l l y H S appears i n the water column, 2  a f t e r the v e r n a l plankton  and  generally in spring,  bloom.  In l a t e summer or e a r l y f a l l , water  develops  a dense, w e l l - a e r a t e d body of  i s produced i n Haro S t r a i t by  151  i n t e n s i v e t i d a l mixing  of  warm, cold  l o w - s a l i n i t y s u r f a c e water from the S t r a i t of Georgia with , s a l i n e , oceanic upwelled water d e r i v e d from the C a l i f o r n i a  Undercurrent  system that moves inward along Juan de Fuca  (Waldichuk,  1957;  replacement  of the bottom water i n the deeper  Strait  nearby  and  S a t e l l i t e Channel water  Thomson,  inlets.  1981).  This  leads to  complete  b a s i n s of  T h i s dense oxygenated  almost u n d i l u t e d ,  a  Strait  Georgia  water  reaches  since at t h i s time the  input from the Cowichan e s t u a r y i s at i t s minimum.  then  able  to d i s p l a c e the bottom water of Saanich  salinity  has  Flushing  seems to occur  over  the  been  sill  slightly  decreased  by  salt  It  Inlet  is  whose  entrainment.  i n boluses of dense water which  mainly d u r i n g f l o o d i n g t i d e  fresh  spills  (Anderson and  Devol,  1973). T h i s water renewal takes p l a c e during most years; however, the  extent  little  of f l u s h i n g v a r i e s widely from year  year.  When  f l u s h i n g o c c u r s , stronger anoxic c o n d i t i o n s develop d u r i n g  the f o l l o w i n g 4.2.2  to  spring.  PHYTOPLANKTON Phytoplankton  pattern  biomass  i n Saanich I n l e t  u s u a l l y r e p o r t e d i n temperate  major s p r i n g bloom and a s m a l l e r f a l l  shows  the  nearshore waters bloom).  induced  by g e n e r a l seasonal c l i m a t i c v a r i a t i o n s ,  series  of  events  (due to winds,  supply  the euphotic zone with n u t r i e n t - r i c h intermediate  tides,  river  1 52  by  (i.e. a  Between these  peaks,  e r r a t i c summer blooms produced  bimodal  occasional  are  two a  mixing  run-off e t c . ) which l o c a l l y waters  (Takahashi dominated  et  al.,  1977).  accompanied  numerous species production  in  by  the  water  and  fall  winter,  inner  dinoflagellates,  column.  fjord  is relatively  s p r i n g bloom and The  phytoplankton  The turbulent  and  Calvert,  are  t i d a l mixing i n  low,  thermal  (Parsons et a l . ,  GENERAL GEOLOGY OF THE The  was  first  summary  general  (Fig.  24)  in d e t a i l is  primary  because  population  of  is  then  nanoflagellates  f r o n t a l zone,  associated  1983). T h i s zone was high  has  with  a l s o been  characterized  surface c h l o r o p h y l l .  SAANICH REGION  geology of the  described  most  stratification  the S a t e l l i t e Channel,  by high primary p r o d u c t i v i t y and 4.2.3  the  1987).  presence of a b i o l o g i c a l  demonstrated  are  nanoflagellates,  dominated by v a r i o u s diatoms, d i n o f l a g e l l a t e s and (Sancetta  blooms  (Takahashi et a l . , 1978). In summer, the  n u t r i e n t d e p l e t i o n by the the  spring  by c e n t r i c diatoms while i n  occasionally  of  The  southern part of Vancouver I s l a n d by Clapp (1913), and  taken from t h i s work (see  the  following  also  Muller,  1980). The Vancouver Series.  rocks  Group, The  andesites minor  oldest  (Paleozoic  pyrite.  are  members  c h i e f l y the Vancouver V o l c a n i c s and  Vancouver V o l c a n i c s  and  age)  c o n s i s t mainly of  b a s a l t s with numerous quartz They a l s o c o n t a i n  1 53  and  the  the Sicker  metamorphosed  epidote  numerous pockets  of  of  veins  and  limestone  Fig. 24: General geology of southern Vancouver Island  (known as the Sutton Formation). andesine  and  chlorite.  hornblende,  The  hornblende,  basalt  The a n d e s i t e c o n s i s t s mainly of  the l a t e r being  i s mainly composed  minerals.  Vancouver  volcanics,  hornblende  phenocrysts.  metamorphosed sedimentary  The  origin.  i s mainly composed of  These rocks are,  The  biotite,  chlorite,  sedimentary  and  These  rocks and  a  the  and  were  epidote,  while  plagioclases  (varying and  magnetite with  The  and  with highly  materials, the  with  volcanic  deformed  during  beween  labradorite  hornblende,  to  schists  the  has a l s o been  and b i o t i t e .  Pyrite,  are a l s o found as a c c e s s o r y m i n e r a l s . 1 55  of in  of  quartz,  of quartz  veinlets  reported  in  and q u a r t z ,  magnetite,  and  Saanich  andesine  g r a n o d i o r i t e c o n s i s t s c h i e f l y of  with some o r t h o c l a s e ) ,  Late  the Wark gabbro  p l u s v a r y i n g amounts  and t i t a n i t e . The presence pyrite  some  feldspars.  intermediate  from  and  chiefly  Wark and C o l q u i t z gneisses c o n s i s t mainly  Saanich  (mainly andesine, hornblende  contain  C o l q u i t z g n e i s s (quartz d i o r i t e ) and the The  gneiss.  extensively  composition  granodiorite.  impregnated  more  i n t r u d e d by p l u t o n i c rocks which formed  (with  composition)  andesite  however,  schists  argillaceous  c o n s i s t mainly of c h l o r i t e and a l t e r e d  biotite,  to  to the  and interbedded with s c h i s t s of both v o l c a n i c  plagioclase,  diorite),  labradorite  S i c k e r S e r i e s i s very s i m i l a r  and  quartz,  gneiss  of  altered  with c h l o r i t e , epidote and quartz as the most common  secondary  Jurassic  largely  the Wark feldspar with some  t i t a n i t e and a p a t i t e  The  chemical  (1913), i s given In rocks  composition in Table  the northern (the  of these rocks,  to  abundance, chlorite contain  quartz,  epidotes.  post-Eocene  drained  sandstones,  and  plagioclases),  by  pyrite. time  and  now  a glaciated valley.  is  s i t u a t e d in Vancouver v o l c a n i c s and Wark  will  biotite,  carbonaceous, and  are  often  i n t o the Saanich g r a n o d i o r i t e b a t h o l i t h ,  from  basin  which  is  ( F i g . 24).  cut  run-off  relative  muscovite,  form a s y n c l i n a l  was  contribute  of  These rocks have been g r e a t l y deformed  Saanich I n l e t occupies  run-off  of  shales are f r e q u e n t l y  the Cowichan r i v e r  Consequently,  mainly  minor s h a l e s . In  i n order  l a r g e amounts of a r g i l l a c e o u s m a t e r i a l s ,  impregnated with in  The  sedimentary  They c o n s i s t  they a l s o c o n t a i n ,  f e l d s p a r s (mainly and  a s e r i e s of  Group) i s found.  unmetamorphosed conglomerates, addition  Clapp  30.  part of the area,  Cowichan  reported by  I t s c e n t r a l part while  gneiss  its  head  (Fig.  24).  the c e n t r a l part of the basin  mainly f e l s i c - t y p e minerals  to  the  sediment,  will while  o r i g i n a t i n g from the southern part of the drainage b a s i n  t r a n s p o r t m a t e r i a l s with a more mafic  signature.  The  ( i . e . Fe- and  Mg-rich)  Cowichan River d r a i n s a t e r r a i n dominated by  Cowichan Group and  the S i c k e r S e r i e s and  wide range of m a t e r i a l s .  1 56  i s expected to supply  the a  Table 30: Major element composition of  the  g n e i s s and g r a n o d i o r i t e found  the Saanich area  Si Al Fe Mg Ca Na K Ti P Mn  (wt %) in  (Clapp, 1913).  Saanich granodiorite  Wark gneiss  Colquitz gneiss  29.28 9.39 3.82 1 .53 3.17 2.62 1 .78 0.36 0.14 0.11  22.75 9.55 7.40 1 .70 7.15 2.36 1 .33 0.48 1.13 0.15  29.93 8.38 3.38 1 .64 2.57 2.61 1.19 0.18 0.88 0.12  157  4.2.4  SAMPLING The  sampling  sediment 19,  samples  1983  with  l o c a t i o n s are shown i n F i g . (SAG1  a  periods  where of  Shipek grab sampler,  deployment  the  and  (Pedersen e t .  moored sediment  s t a t i o n s are i n d i c a t e d  Fifty  to SAG60) were c o l l e c t e d on A p r i l  obtained' with a g r a v i t y c o r e r stations  25.  t r a p s were  of the sediment  three  18  and  cores  a l , 1985) also  five  were  from the 2  deployed.  t r a p s at each  of  The these  i n F i g . 26, and the depth of c o l l e c t i o n of  settling particulates  i s indicated  i n F i g . 27.  F u r t h e r d e t a i l s on sampling procedures are given i n Appendix I.  4.3  BULK COMPOSITION OF SAANICH INLET SEDIMENTS  The detail Gross  sediments  of  Saanich I n l e t were  by Gross et a l . (1967).  distinguished  Three by  (1963),  which p a r t l y r e f l e c t  and  t h e i r environment  production  and  clayey s i l t s . restricted  in  (1964),  and  recognized.  physical  They  characteristics  i s covered with o r g a n i c -  The combination of high primary  circulation  produces  an  oxygen  d e f i c i e n c y i n the deep water which leads to anoxic c o n d i t i o n s the  e n t i r e sediment column,  the p r o d u c t i o n of hydrogen  158  are  of d e p o s i t i o n .  The deep c e n t r a l b a s i n of the i n l e t r i c h , diatomaceous,  described  Gucluer and Gross  broad types can be  t h e i r chemical  first  in  sulphide,  F i g . 25: Sampling  159  locations.  SN  11  complete  •  C&N a n a l y s i s  analysis only  0.8  SI-9  i—i A  S  1 1 1 1 1F 1M 1A M1 J1 J1 1— i O N D J A S  1 983  Fig.  26:  O  1984  Period of deployment of the t r a p moorings.  160  1  sediment-  SN  SI-9  0.8  10  0  20  Length(km)  Fig.  27:  L o n g i t u d i n a l t r a n s e c t of Saanich I n l e t showing the p o s i t i o n i n g of the sediment traps.  161  and  the p r e s e r v a t i o n of a varves  sill,  deposit  shallow  amount  conditions  topographic  stronger from  lower  i s coarser-grained  turbulent  sill  (mainly  fine p a r t i c l e s .  clays,  The  The  1981).  opal,  coarsest  fairly  poorly  s o r t e d sands,  matter.  This  sill  is  a  relatively  and  Re-suspended m a t e r i a l s organic  matter)  may  sediments are  inlet.  found at  shallow  They g e n e r a l l y c o n s i s t  with a low organic  of  carbon  content,  powders from 16 s t a t i o n s were  analyzed  gravels.  MINERALOGY OF Unorientated  by  containing  i n the c e n t r a l basin which a c t s as a t r a p  near the shores of the  4.3.1  the  b e t t e r s o r t e d , which r e f l e c t s more  (Thomson,  depth,  occasional  organic  On  feature which a l s o c o i n c i d e s with a region of  t i d a l currents  the  and  of opal and  of d e p o s i t i o n .  e v e n t u a l l y be d e p o s i t e d  and  1963).  the sediments c o n s i s t of a l i g h t o l i v e - g r e y s i l t  significantly  for  (Gross et a l . ,  SAANICH INLET SEDIMENTS  pressed  X-ray d i f f r a c t o m e t r y in order  to i d e n t i f y t h e i r major  mineral  components. The the  m i n e r a l o g i c a l composition  of c o a s t a l sediments  mineralogy of the nearby parent  lithogenous drains  m a t e r i a l i n Saanich I n l e t  rocks.  The  main  reflects  source  i s the Cowichan River which  an area dominated by the Cowichan Group ( a l s o c a l l e d  Nanaimo S e r i e s ) and Quartz,  the S i c k e r S e r i e s ( s e c t i o n 4.2.3; F i g  feldspars,  hornblende,  and micas were r e a d i l y i d e n t i f i e d 162  in  of  c h l o r i t e and/or a l l the sediments  the  24).  kaolinite, analyzed.  O c c a s i o n a l l y , p y r i t e and c a l c i t e c o u l d a l s o be  found.  The r a t i o s of the peak i n t e n s i t i e s of quartz (at 2.46  A)  or  0  plagioclase were  (at  4.04  o  A) to c h l o r i t e and/or  much higher i n the s i l l  basin  and  Cowichan Bay  kaolinite  turbulent  samples  waters. only  A  environments  (Table 31  and  32).  d e t e c t a b l e i n the deep  basin  in  samples  the Cowichan I l l i t e was  A  which  did  (Table 33).  a  in  deeper  while o f t e n oozes,  i n some nearshore  Bay. also i d e n t i f i e d not  significant  i n these sediments by peaks at 10  expand on g l y c o l a t i o n ,  while peaks k a o l i n i t e . The  amount of k a o l i n i t e was  revealed  at  minerals The  chlorite  and  illite  7  A  presence  by  a  d e t a i l e d study of the c l a y mineralogy i n the c e n t r a l b a s i n kaolinite,  and  I t i s a l s o r e l a t i v e l y more abundant  i n d i c a t e d the presence of c h l o r i t e and/or of  shallow  diatomaceous  occurs i n l a r g e r q u a n t i t i e s , r e l a t i v e to c l a y s , and s i l l  A)  Therefore,  while c l a y s predominate  s i m i l a r approach showed that hornblende,  barely  7  and nearshore sediments than i n the  quartz and f e l d s p a r s are more abundant i n r e l a t i v e l y more  (at  were found to be the main  more where clay  (Powys, p e r s . comm.). localized  i n f l u e n c e from the g n e i s s formations and  Saanich  g r a n o d i o r i t e b a t h o l i t h should a l s o be expected and  apparent  i n adjacent nearshore  sediments.  163  the more  Table 31: Peak  intensity  Quartz (2.46 h) / c h l o r i t e  and k a o l i n i t e  C e n t r a l basin SAG1 SAG7 SAG 1 3 SAG 1 5 SAG26 SAG33 SAG36 SAG43  0.80/0.90 0.80/0.65 0.85/0.65 1.20/1.05 1.00/1.10 1.10/1.10 1.30/1.30 1.80/1.05 Sill  ratios.  sediments = 0.9 =1.2 = 1.3 = 1.1 = 0.9 = 1.0 = 1.0 = 1.7  sediments  SAG 4 7 SAG50 SAG51 SAG53  2.60/0.70 3.05/0.60 1.75/0.80 2.75/0.75  SAG56 SAG60  1.85/1.50 = 1.2* 2.25/1.60 = 1.4 Nearshore  SAG22 SAG 3 2  = = = =  3.7 5.1 2.2 3.7  sediments  2.90/0.70 =4.1 5.30/0.30 = 18  * Cowichan Bay  1 64  (7 A)  Table 32: Peak Plagioclase  intensity  o  (4.04 A) / c h l o r i t e  and k a o l i n i t e  C e n t r a l basin SAG 1 SAG7 SAG 1 3 SAG 1 5 SAG26 SAG33 SAG36 SAG43  ratios.  sediments  0.95/0.90 == 1.60/0.65 == 1.40/0.65 == 1.85/1.05 == 1.10/1.10 == 1.20/1.10= = 1.00/1.30 == 1.70/1.05 == Sill  1.1 2.0 2.2 1.8 1.0 1.1 0.8 1.6  sediments  SAG47 SAG 50 SAG51 SAG53  2.05/0.70 2.80/0.60 1.90/0.80 2.35/0.75  SAG 5 6 SAG 60  1.80/1.50 = = 1 .2* 1.60/1.60 == 1.0  == == == ==  2.9 4.7 2.4 3.1  *  Nearshore SAG22 SAG 3 2  sediments  2.70/0.70 == 3.9 3.20/0.30 == 10.7  * Cowichan Bay  165  o  (7 A)  Table 33: Peak Hornblende  intensity  (8.40 A) / c h l o r i t e  ratios. and k a o l i n i t e  C e n t r a l basin SAG 1 SAG7 SAG 1 3 SAG 1 5 SAG26 SAG 3 3 SAG 3 6 SAG43  < < <  <  0.2/0.90 0.2/0.65 0.2/0.65 0.2/1.05 0.2/1.10 0.3/1.10 0.2/1.30 0.2/1.05 Sill  SAG47 SAG 50 SAG 51 SAG 5 3  <  sediments = < < < = = = <  0.2 0.3 0.3 0.2 0.2 0.3 0.2 0.2  sediments  0.2/0.70 0.3/0.60 0.2/0.80 0.8/0.75  = = < =  0.3 0.5 0.3 1.1  0.45/1.50 = 0.3* 0.65/1.60 = 0.4  SAG 5 6 SAG 60  Nearshore SAG 2 2 SAG32  sediments  1.7/0.70 = 2.4 0.7/0.30 = 2.3  * Cowichan. Bay  166  (7 A)  4.3.2  GEOCHEMISTRY OF SAANICH INLET SEDIMENTS 4.3.2.1 ORGANIC MATTER The  sediments  significantly sediments in  deposited  more  although  Cowichan  tendency  Bay  in  organic  the  central  carbon  than  basin  the  contain  shallow-water  s u b s t a n t i a l c o n c e n t r a t i o n s are a l s o  (Fig.  28;  f o r a gradual  Appendix IV-1).  There  observed  is  also  i n c r e a s e in the c o n c e n t r a t i o n of  carbon towards the head of the In  the  organic  inlet.  order to e x p l a i n such a d i s t r i b u t i o n ,  source(s) of the organic matter,  lithogenous d e t r i t a l m a t e r i a l s and r e g u l a t e the accumulation  a  one  must c o n s i d e r  the p o t e n t i a l d i l u t i o n  by  the hydrodynamic f a c t o r s which  of low-density  particles  in  low-energy  depositional basins. Plankton  is  usually  the  principal  m a t e r i a l s i n marine sediments (e.g.  1983).  However, i n a l a n d - l o c k e d area such as Saanich  Malcolm and nitrogen  Price,  ratio  importance  et  al.,  1982;  t e r r e s t r i a l component can a l s o be present  Hedges and Parker,  of  1976;  1984;  can  Qr  these  Gadel,  1979;  two  be used to  sources.  1972;  Jorgensen, Inlet, a (e.g. Hunt,  Walsh et a l . , 1981;  Naik and Poutanen, 1984). The  (C g/N)  organic  Nissenbaum and Kaplan,  and C a l v e r t ,  1966;  Primuzic  of  Morris  significant  1977;  source  assess  Terrestrial  carbon to  the plant  relative debris  c o n t a i n s much l e s s n i t r o g e n than p l a n k t o n i c m a t e r i a l s (Table Accordingly,  a high C  /N  ratio  167  in the sediment w i l l , suggest  34). a  F i g . 28:  Distribution 168  of o r g a n i c c a r b o n .  Table  34:  C/N r a t i o  (% dry wt.) of organic m a t e r i a l s  of  marine and t e r r e s t r i a l o r i g i n .  Marine plankton  Seed p l a n t s River p a r t i c u l a t e s (Amazon) R i v e r sediments (Rhine) Forest s o i l River p a r t i c u l a t e s (Loch E t i v e ) 1 - Cited  i n Bowen  C/N  References  4.9 5.7 5.2  Vinogradov (1953) R e d f i e l d et a l . (1963) Malcolm and P r i c e (1984)  13.8 8.5-15  1  Rankama and Sahama W i l l i a m s (1968)  (1950)  21  DeGroot  13.5 17.3  Stuermer et a l . (1978) Malcolm and P r i c e (1984)  (1979).  169  (1973)  1  significant this  terrestrial  input.  r a t i o to q u a n t i f y the r e l a t i v e p r o p o r t i o n  of m a t e r i a l s .  et a l . ,  1980).  p r o t e i n s ) tend gradual  (e.g.  of the two  organic  i n the C/N r a t i o  thus producing  of d i a g e n e s i s  1979;  Landing and F e e l y ,  of the marine component of the  (e.g.  Degens, 1981;  1970; Ulen,  1978; Rosenfeld,  Honjo et a l . ,  1982; Cronin and  1983; Gardner et a l . , 1983; Wassman, 1983). In c o n t r a s t ,  decrease  i n the C/N r a t i o of aging  organic  detritus  1965;•Harrisson and Mann, 1975; Roman, 1977; R i c e , 1984)  and s u r f i c i a l sediments (Suess and M u l l e r ,  been  observed  of  organic  complicated  biomass. matter  in  by the presence of ammonium  p o s i t i o n s of i l l i t e s and v e r m i c u l i t e s  of  terrestrial  an  estimate  protein-rich of the C/N  sediments  fixed  may  be  i n the i n t e r l a y e r  (Muller,  1977),  problem a r i s e s mainly at low organic carbon  Consequently,  1983; Nedwell,  A l s o , the d e t e r m i n a t i o n fine-grained  (Newel,  1979) has o f t e n  and a t t r i b u t e d t o the s y n t h e s i s  m i c r o b i a l or benthic  very  a  i t s t r a n s p o r t to the sediment and the e a r l y  stages  this  their  compounds (mainly  to be p r e f e r e n t i a l l y m i n e r a l i z e d ,  organic matter during  ratio  types  Banse, 1974; Slawik et a l . , 1978; Sharp  Moreover, N-containing  increase  Morris,  however, to use  The C/N r a t i o of phytoplankton may vary with  n u t r i t i o n a l status  an  It i s difficult,  of the r e l a t i v e input  although  concentrations. of marine  organic m a t e r i a l s based on C/N r a t i o s alone  would  and be  t e n t a t i v e , even when the end-members are w e l l c h a r a c t e r i z e d .  However, between  because  of  the l a r g e d i f f e r e n c e i n  the two types of m a t e r i a l s , 170  nitrogen  content  q u a l i t a t i v e c o n c l u s i o n s can  F i g . 29: Distribution of the C / N ratio. 171  still  be drawn. The  distribution  of  the C  /N r a t i o s  in  Saanich  Inlet  The  sill  sediment  samples,  e a s t e r n branch of  the  Satellite  Channel,  org sediments  is  recovered  from  shown  in F i g .  the  d i s p l a y r e l a t i v e l y low C / N KJ L  a  biological  productivity, consistent  central the  (8.3 + 0.5). The presence of  y  this  area,  characterized  with  the  presence  planktonic o r i g i n  of  organic  matter  high  with  a  sediment.  On  the C g / N r a t i o s of the f i n e - g r a i n e d sediment from the Qr  basin are s l i g h t l y higher (9.8 + 1.3),  thus  suspension  could  River as a f i n e  which became trapped i n the stagnant water column  central basin.  observed  in  Cowichan  Bay,  significant  suggesting  This material  been brought i n t o the i n l e t by the Cowichan  several  nearshore  samples  and  which suggests that the Cowichan  source  of  A higher p r o p o r t i o n of t e r r e s t r i a l d e b r i s  of  t e r r e s t r i a l organic  C g / N r a t i o i n the two southernmost or  also  by  (1983) and i s  i n the u n d e r l y i n g  presence of some t e r r e s t r i a l m a t e r i a l .  have  the  in  ratios  was demonstrated by Parsons et a l .  predominantly average,  front  29.  samples  is  particularly  in  R i v e r c o u l d be matter.  A  a  higher  i n the anoxic  basin  i n d i c a t e s the presence of some t e r r e s t r i a l d e b r i s from  the  Goldstream R i v e r . There  i s no  w e l l - d e f i n e d primary  production  pattern  in  Saanich I n l e t which c o u l d r e a d i l y e x p l a i n the i n c r e a s e i n organic carbon monthly  i n the sediment towards the head of the f j o r d .  In  fact,  measurements over a two-year p e r i o d at s t a t i o n s SI9 and 1 72  SN0.8 ( C a l v e r t , generally  higher at the mouth of the  general  pattern  (Lebrasseur, Satellite  of  1954)  Channel  distribution in  unpublished) i n d i c a t e that primary  productivity and  reported  for  other  (Parsons  et  al.,  1983).  of  the Cowichan e s t u a r y ,  This  would  produce an  and to  due  away  sedimentation by  the  and  relative gradually  i n c r e a s e i n the C  % in  the  by  the  35),  and  org  the  sill.  This  r e l a t i o n s h i p found  sedimentation  However,  is  supported (Table  between % C g Q r  in  surficial  r a t e s i n four d i f f e r e n t cores  (Fig.  t h i s d i l u t i o n by l i t h o g e n o u s m a t e r i a l s i s not  only f a c t o r c o n t r o l l i n g the organic carbon c o n c e n t r a t i o n of sediments. Simple dilution r e l a t i o n s h i p between %C and org c  100  x [C  ar  /(C  ar  + L  ar  )],  where C  ar  a r  inorganic materials;  30). The  therefore  decrease inlet,  in as  be  Fig.  is a  constant  these  accumulation  i s a v a r i a b l e accumulation  f o r t u i t o u s and,  carbon accumulation shown i n Table 36.  the  would produce a hyperbolic sedimentation r a t e s ( i . e . %C = org  rate of organic carbon and L  must  the  Detrital  decrease  r a t e s measured by v a r i o u s authors  inverse  sediments 30).  from  in  variations  to the  c  sediment  fjords  Therefore,  sediment components.  to be higher near the s i l l ,  the  front  p a t t e r n of organic matter must r e f l e c t  input i s expected  southward.  in accord with  the p r o x i m i t y of a b i o l o g i c a l  the degree of d i l u t i o n by other  proximity  inlet,  production i s  linear  relationship  in part,  r a t e s towards the head  T h i s decrease  1 73  produced  reflects  r a t e of obtained by  the  of  the  primarily  Table 35: Sediment accumulation Station  SI-9 SI-7 G 1 SI-3 SN0.8 CP4  w %c (mg/cm2.yr) org 257 270 144 90 93 95 42  3.00 4. 1 0 4.54 5.35  r a t e s (w) i n Saanich  Inlet.  References  T h i s work Matsumoto and Wong (1977) Carpenter and Beasley (1981) Carpenter and Beasley (1981) Matsumoto and Wong (1977) T h i s work Powys (pers. comm.)  174  W  (mg/cm  .yr)  F i g . 30: R e l a t i o n s h i p between o r g a n i c carbon content and sediment accumulation r a t e i n Saanich Inlet sediments.  175  Table 36: Carbon accumulation Saanich Stat ion  rates  i n the deep basin of  Inlet. Sediment accumulation rate (mg/cm . y)  %C surface sediment  C accumulation rate (mg/cm .y)  CP4  42  5.35  2.25  SN0.8  95  4.54  4.31  G  144  4.10  5.90  SI-9  257  3.00  7.71  176  differences  in  the carbon  f l u x e s to the sediment  (see  section  4.4.1). Although highly  the  C g / N r a t i o of the sediment Qr  productive  indicates organic  biological  front  in  the  an organic input of predominantly carbon  considering  content  i s very low.  sill  intense  marine  origin, explained  As mentioned  represents a topographic h i g h i n a zone  the b i o l o g i c a l  (which  front).  of  O r g a n i c - r i c h p a r t i c l e s of r e l a t i v e l y  sill  ( s e c t i o n 4.3.1).  by geochemical  sediments  which  This  matter  summary, in  it  Saanich  hydrodynamic  a l s o suggest  but c o n c e n t r a t e prevail,  and  detritus  at  appears  Inlet  factors  hypothesis  is  in  of  further  that they c o n s i s t of  a  the lag  ( s e c t i o n 4.3.2.3).  that the d i s t r i b u t i o n  sediments  low  i n the  data o b t a i n e d from the a n a l y s i s of  d e p o s i t e n r i c h e d i n f e l d s p a r and q u a r t z In  the  i s r e s p o n s i b l e f o r the occurrence of  c e n t r a l b a s i n . T h i s i s c o n s i s t e n t with the m i n e r a l composition  supported  by  relatively  w i l l not accumulate i n such an environment and w i l l ,  sediments  its  earlier,  p a r t , be d e p o s i t e d under the q u i e t e r c o n d i t i o n s p r e v a i l i n g  these  the  Channel  the nature of the environment of d e p o s i t i o n and  t i d a l mixing  density  Satellite  T h i s can be  hydrodynamic p r o p e r t i e s of o r g a n i c matter. the  underlying  is  controlled  which hinder i t s accumulation  of  organic  mainly on the  by sill  i t i n the c e n t r a l b a s i n where q u i e t e r c o n d i t i o n s by  the  dilution  due  to a l a r g e r  mouth of the i n l e t which  input produces  of  mineral  a  gradual  i n c r e a s e i n organic carbon c o n c e n t r a t i o n towards the head. 177  4.3.2.2 CARBONATE The  carbonate  content of most of the  generally  low  lens  metamorphosed  of  Formation) The  ( l e s s than 3.5%)  c l o s e l y resembles limestone  sediments  except near Bamberton,  limestone  (belonging  has been commercially e x p l o i t e d carbonate  inlet  to  is  where  the  a  Sutton  ( F i g 31).  d i s t r i b u t i o n obtained from the present  that r e p o r t e d by Gucluer and Gross  work  (1964).  The  quarry c l e a r l y a c t s as a p o i n t source f o r most of  the  carbonate present i n the  inlet.  4.3.2.3 MAJOR ELEMENTS The major element are  shown i n Appendix  c o n c e n t r a t i o n s of Saanich I n l e t  sediments  IV-1.  4.3.2.3.1 ALUMINIUM Aluminium r e f l e c t s p r i n c i p a l l y the d i s t r i b u t i o n of and from  clay minerals. the s i l l  I t s c o n c e n t r a t i o n shows a  to the head of the i n l e t  (Fig.  feldspars  gradual  decrease  32) which r e f l e c t s  d i l u t i o n by opal and o r g a n i c matter. It be  i s b e l i e v e d that  relatively  i n the c e n t r a l b a s i n c l a y m i n e r a l s w i l l  more important than on the s i l l  where  feldspars  w i l l be predominant.  T h i s i s supported by the mineralogy of these  sediments,  4.3.1)  following  (section  and  by the data  presented  in  the  sections.  4.3.2.3.2 SILICON The  d i s t r i b u t i o n of s i l i c o n 178  i s mainly c o n t r o l l e d by  diatom  F i g . 3 1 : Distribution of 179  CaC0 . 3  F i g . 32: Distribution of A l . 180  opal and q u a r t z .  The  source of the opal i s the same as that of a  major p a r t of the marine component of organic matter, these  two  phases are expected  properties, found  a  and  t o have q u i t e s i m i l a r hydrodynamic  good c o r r e l a t i o n between S i and % C g  should  Q r  i n sediments which are not s t r o n g l y a f f e c t e d by  input.  since  terrestrial  In c o n t r a s t , quartz i s a very r e s i s t a n t component of many  different  rocks  weathering  and t r a n s p o r t .  coarser  and  fractions  depositional  remains  virtually  As such,  environments  re-suspended.  Hence,  one  A p l o t of S i / A l vs % C g o r  where  in  i n the  turbulent  finer-grained  sediment  o p a l , and organic matter  would  expect  are  an  antipathetic  33.  A reasonably  carbon.  i s shown i n F i g .  (r=0.68).is found  during  i t tends to be found  r e l a t i o n s h i p between quartz and organic  good c o r r e l a t i o n  unaltered  of sediments and to accumulate  c o n s t i t u e n t s such as c l a y m i n e r a l s ,  i n the diatomaceous ooze, thus  i n d i c a t i n g a c o - v a r i a t i o n between opal and o r g a n i c matter. On other hand,  i n the s i l l  are  higher  always  c o n t e n t s , except indicates  a  Moreover,  this  decreases. nearshore most  be  expected  samples,  from  their  the S i / A l  ratios  organic  carbon  the Cowichan Bay where a higher  higher p r o p o r t i o n of discrepency  tends  terrestrial to  C/N  organic  increase  as  ratio matter.  the  ^^ g o r  This  i n d i c a t e s that the sediments from the s i l l  and  areas  are comparatively e n r i c h e d i n non-biogenic  Si,  probably  significant  in  than  and nearshore  the  in  amounts  the of  form  of  feldspars 181  detrital must  also  quartz, be  although  present,  as  0  2  4 %C  Fig.  33:  6  org  R e l a t i o n s h i p between S i / A l and  182  %C g Qr  i n d i c a t e d by the r e l a t i v e l y high A l c o n c e n t r a t i o n s found samples ( F i g . 32, Appendix These  i n these  IV-1).  o b s e r v a t i o n s are c o n s i s t e n t with the presence  on  the  sill  of a c o a r s e r - g r a i n e d l a g phase r e l a t i v e l y e n r i c h e d i n q u a r t z  and  feldspar  composition  which  was  also indicated  of these sediments ( s e c t i o n  by  the m i n e r a l o g i c a l  4.3.1).  4.3.2.3.3 POTASSIUM The  main  potassium  minerals  found  are K - f e l d s p a r (K/Al ~ 1.4),  1.4) and m u s c o v i t e / i l l i t e The basin  which  (K/Al ~  host  0.58  -  (K/Al ~ 0.1 - 0.3).  and have v a l u e s which would be  the  central  expected  from  or a mixture of b i o t i t e and K-poor a l u m i n o s i l i c a t e s  such  as c h l o r i t e and p l a g i o c l a s e . In the s i l l the  biotite  K/Al r a t i o s tend t o be s l i g h t l y higher i n  ( F i g . 34)  illite  i n Saanich sediments  and nearshore  sediments,  K/Al r a t i o i s much too low t o i n d i c a t e the presence  quantities presence  of  K-feldspar,  although i t does not  rule  of l a r g e out the  of t h i s phase (and b i o t i t e ) as a minor component.  4.3.2.3.4 CALCIUM AND SODIUM Calcium feldpars,  and sodium are mainly a s s o c i a t e d while  the  calcium  distribution  with  plagioclase  i s also  strongly  i n f l u e n c e d by CaCOg. The branch  Na/Al of  the  r a t i o s are s i g n i f i c a n t l y h i g h e r i n S a t e l l i t e Channel (av.~0.35)  sediments than i n the c e n t r a l b a s i n (av.~0.25; suggesting  the  presence  and  the in  eastern nearshore  F i g . 35 and 37),  of l a r g e r q u a n t i t i e s of p l a g i o c l a s e 183  in  F i g . 3 5 : Distribution of the Na/AI ratio. 185  F i g . 3 6 : Distribution of the C a / A l 186  ratio.  Na/Al Central  Basin  .10  0  .20  .30  .40  .50  Sill  n ii n  J_L  0  20  .10  .30  .40  50  .40  .50  .50  Sand  0  .10  .20  Ca/Al  ( c o r r e c t e d for  Central  Basin  i  0  .10  H  r"  1  .30 CaC0 ) o  r  .20  .30  .40  .20  Eq .30  C=L  Sill  .10  0  40  .50  .40  .50  Sand  .10 Fig.  37:  .20  .30  n  Histogram of d i s t r i b u t i o n of the Na/Al and r a t i o s i n Saanich I n l e t sediments. 187  Ca/Al  these  samples.  When  corrected  f o r the presence of  Ca/Al r a t i o s show a s i m i l a r t r e n d If  we  assume  that  CaCO^,  the  i n clays  are  ( F i g . 36 and 37).  the Na and Ca  present  n e g l i g i b l e and that most of the Na and non-carbonate Ca a r e found in  plagioclase,  contributed  the  maximum p r o p o r t i o n  of A l  which  Na-feldspar:  Na/Al = 0.85  Ca-feldspar:  Ca/Al = 0.74  av.  Na/Al ~ 0.22  i . e . a max. of ~25% of the A l i s present as N a - f e l d s p a r .  av.  Ca/Al ~ 0.18  i . e . a max. of ~25% of the A l i s present  a max.  of ~50% of the A l present  a s s o c i a t e d with p l a g i o c l a s e . S i l l sediments: av. Na/Al ~ 0.35 (eastern s i d e ) av.  a max.  as C a - f e l d s p a r .  i n these sediments can be  i . e . a max. of ~40% of the A l i s present as N a - f e l d s p a r .  Ca/Al ~ 0.25  i . e . a max. of ~35% of the A l i s present  i.e.  be  by these f e l d s p a r s can be computed, v i z  Central basin:  i.e.  would  of ~75% of the A l present  as C a - f e l d s p a r .  i n these sediments can be  a s s o c i a t e d with p l a g i o c l a s e . Similar  calculations  f o r the nearshore  sediment  samples  suggest that most of the A l can be accounted f o r by p l a g i o c l a s e . These the  eastern  quartz,  a  composition weathering  c a l c u l a t i o n s confirm part of the s i l l relatively close of  which  contains,  large proportion  to  rocks  the presence of a l a g d e p o s i t on  of p l a g i o c l a s e  andesine as would be  from the S i c k e r S e r i e s 188  besides  expected (Section  detrital (with from  a  the  4.2.3)).  T h i s phase c o u l d account f o r as much as 75% of the A l present these  sediments;  the  aluminosilicates  remainder must be present i n  (K-feldspar,  clay minerals,  other  amphiboles).  The  i n Cowichan Bay  are  Na/Al and Ca/Al r a t i o s  i n the s i l l  significantly  suggesting a higher c o n c e n t r a t i o n of  lower,  sediments  seme  in  clay  m i n e r a l s . T h i s i s c o n s i s t e n t with the data presented i n Tables 31 and 32. In the c e n t r a l b a s i n , p l a g i o c l a s e c o u l d account, at most, for  50%  of  the A l present,  content  in  these  maxima,  since  sediments.  some  Ca  minerals.  This  sediments  which  are  evidence,  based  on  is  and  significantly  basin  the  to  higher  f i g u r e s must  Na can a l s o  thought  the  true  be  for  contain  taken  present the  more  d i s t r i b u t i o n of T i  be  clay  in  as clay  central  basin  clays.  Other  and  Fe  (Sections  suggest that p l a g i o c l a s e - A l  l e s s than 50% of the t o t a l A l i n  accounts  the  central  sediments.  4.3.2.3.5 IRON AND A closely the  These  particularly  4.3.2.2.5. and 4.3.2.2.6), for  thus c o n f i r m i n g  MAGNESIUM  p l o t of %Fe vs %Mg (Fig.  origin  nearshore)  38;  and  shows that both elements co-vary  r=0.92). the three  are v i r t u a l l y  Moreover, sediment  the i n t e r c e p t types  indistinguishable.  (basin,  two elements are e s s e n t i a l l y c o n t r o l l e d by one  or  several  minerals  with  identical  Fe/Mg  sill,  and that  s i n g l e mineral  ratios.  sediments, c h l o r i t e and/or b i o t i t e are the most l i k e l y  189  i s c l o s e to  T h i s suggests  the  very  In  these  phases.  190  The  Fe/Al  basin and The  r a t i o s are s i g n i f i c a n t l y higher  i n Cowichan Bay  than  lowest values are obtained  particularly  i n the s i l l  in  the  central  sediments ( F i g .  from some nearshore  41).  sediments,  and  from the shores adjacent to the Saanich g r a n o d i o r i t e  batholith. In  the diatomaceous ooze,  Fe  (and t h e r e f o r e Mg) c o r r e l a t e s  q u i t e c l o s e l y with A l ( F i g .  39,  distributions  controlled  are  mainly  r=0.94),  suggesting that t h e i r  by  an  aluminosi1icate  (presumably c h l o r i t e ) . There i s a l s o an i n t e r c e p t on the %Fe a x i s corresponding bearing  to ~0.5%  phase  Fe,  to  aluminosilicates.  i.e.  these  there must be an a d d i t i o n a l  sediments  T h i s probably  not  r e f l e c t s an  Fe-  associated  with  input of i r o n  oxides  which have been s o l u b i l i z e d and p r e c i p i t a t e d as i r o n s u l p h i d e s i n the anoxic  sediments.  Since some of the A l must a l s o be  in p l a g i o c l a s e , which i s very low been added as o x i d e s . The Fig.  44)  suggests  plagioclase  i n Fe, even more i r o n must have  titanium d i s t r i b u t i o n  that a minimum of 1-1.5  i n the c e n t r a l b a s i n sediments.  to F i g . 39,  at l e a s t  1-1.5  present  ( s e c t i o n 4.3.2.6,  wt % A l i s present  as  Therefore, according  wt % Fe must have been added to these  sediments as o x i d e s . I n c i d e n t a l l y , a much l a r g e r p r o p o r t i o n of A l in  plagioclase  added as o x i d e s . indicate surpassing hence  the  would r e q u i r e u n r e a l i s t i c amounts of  to  T h i s can be taken as c i r c u m s t a n t i a l evidence  presence  ~25%  Fe  of  plagioclase-Al  in  a  quantity  of the t o t a l A l i n the c e n t r a l basin  suggesting the presence  of Ca and Na 191  be to not  sediments,  in c e n t r a l basin clay  0  2  4 %AI  Fig.  39:  Correlation between %Fe and %A1 I n l e t sediments.  192  i n Saanich  F i g . 4 0 : Distribution of the F e / A l ratio. 193  minerals  (see s e c t i o n 4.3.2.4).  The  Fe/Al  nearshore  sediments  accumulation As  ratios  are  (Fig.  much  lower  40),  reflecting  of p l a g i o c l a s e over c h l o r i t e  f o r the  Na/Al and Ca/Al  ratios,  in  eastern the  i n these  the F e / A l  sill  and  preferential environments.  ratios  of the  Cowichan Bay samples have intermediate values between the eastern sill  and the c e n t r a l b a s i n . Fe and K c o r r e l a t e w e l l i n the deep basin  suggesting phase  as  e i t h e r that these elements are c o n t r o l l e d by the same  (such  phases  as an i l l i t e  or b i o t i t e ) o r , more l i k e l y ,  f o r R and c h l o r i t e f o r Fe  t h e r e f o r e would be present diatomaceous indicates  to  ooze.  The  This sediments  (such and  i n the same p r o p o r t i o n throughout  the  i n t e r c e p t of the r e g r e s s i o n  minerals,  two  Mg),  line  also  accounted  thus c o n f i r m i n g the c o n c l u s i o n s drawn  the F e - A l c o r r e l a t i o n concerning  these  and  that a t l e a s t ~1 wt % of the i r o n cannot be  by K-bearing  from  by  which would have i d e n t i c a l hydrodynamic p r o p e r t i e s  muscovite/illite  for  ( F i g . 42; r=0.87),  the  a d d i t i o n of Fe oxides  sediments. Fe-K  r e l a t i o n s h i p breaks down i n s i l l  which are comparatively  higher  and  nearshore  i n K ( F i g 42  and 43).  T h i s may be due t o the presence of small q u a n t i t i e s of K - f e l d s p a r in  the  lag deposits  (with a K/Al~1.4,  only 0.2-0.4 wt  feldspar  i s r e q u i r e d t o add the 0.3-0.6 wt % of  biotite,  or a l t e r n a t i v e l y due t o the presence of r e l a t i v e l y more  illite  compared t o c h l o r i t e  i n these 1 94  sediments.  K  % Al-  required),or  Fe/Al Central  i  Basin  r  00  .20  .40  .60  .80  1.00  Sill  i  r  00  r  T  .20  .40  .60  .80  1.00  .20  .40  .60  .80  1.00  Sand  .00  Fig.  41:  Histogram of d i s t r i b u t i o n Saanich I n l e t sediments.  195  of  the  Fe/Al  ratios  in  O S i II A S a n d  1  1  1  0  1  •  i  "  i  0.5  i  i  i  I  1.0  I I  I  1.5  %K Fig.  42:  C o r r e l a t i o n " between %Fe and %K I n l e t sediments.  196  i n Saanich  F i g . 4 3 : Distribution of the F e / K ratio. 197  The sill  presence  of a s i g n i f i c a n t amount of hornblende  (particularly  nearshore  toward  sediments  the  could  in  estuary)  a l s o be deduced from  (Table 33). The accumulation these  Cowichan  i n the  and  the  some  XRD  data  of t h i s r e l a t i v e l y heavy m i n e r a l i n  samples i s c o n s i s t e n t with the formation of a l a g d e p o s i t  these shallower environments.  composition, elemental assess.  the  impact  composition I t should,  Because of i t s h i g h l y v a r i a b l e  of the presence  of  the  sill  of hornblende  sediment  on  the  is difficult  to  however, be minor, although  some of the Fe and Mg present  i n these samples.  present only as t r a c e s i n the c e n t r a l b a s i n  i t could contain T h i s m i n e r a l was  sediments.  4.3.2.3.6 TITANIUM There  is a  strong c o r r e l a t i o n between T i and  diatomaceous ooze ( F i g . of  sill  and nearshore  Al  i n the  44, r=0.97). In c o n t r a s t , the T i content  samples i s s i g n i f i c a n t l y  lower and does not  c o r r e l a t e with A l . Titanium rutile), Al  occurs  ratio  reported  titanium  oxides  which are s t a b l e d u r i n g weathering,  in c l a y minerals  Ti/Al  as  (e.g.  (e.g.  Deer et a l . ,  (ilmenite,  and s u b s t i t u t e s f o r  1966).  An i n c r e a s e  with quartz content and g r a i n s i z e has Hirst,  1962;  in l a g d e p o s i t s as a r e s u l t of c u r r e n t . s o r t i n g . apparent  in  Saanich  often  in been  Spears and K a n a r i s - S o t i r i o u , 1976)  and has been a t t r i b u t e d t o the r e l a t i v e accumulation  not  anatase,  I n l e t s i n c e the  sediments have a lower T i / A l r a t i o . 198  sill  of T i oxides  Such a t r e n d and  is  nearshore  T h i s suggests e i t h e r that T i  199  does  not occur p r i m a r i l y as a d i s c r e t e heavy m i n e r a l or that  such  mineral  does  environments,  accumulate  i t s effect  in  high  energy  if  depositional  on the T i / A l r a t i o i s masked  by  the  simultaneous accumulation of f e l d s p a r s . A  further  indication  of the p a r t i t i o n i n g  of  obtained by studying i t s r e l a t i o n s h i p with Fe ( F i g . good  correlation  central  basin  (r=0.93).  regression  suggesting  the  Moreover,  effect  sediments  are  identical  the  same  on  T i does accumulate  the in  opal  strongly  The s l o p e s of  in  environments,  both  mineral;  however,  T i / A l r a t i o i s concealed  A l due to the accumulation of  and  conclusions  organic  drawn  matter.  earlier  iron  i n the s i l l  c o n t a i n only t r a c e s of T i (Deer et a l . , of  A l , Fe  i n the  (r=0.94).  basin sediments with the same  that  increase  by  unlike  This  be  45). A very  the  sill  have i n v a r i a b l y an excess of~0.1% T i when compared  central  implies  lines  control  sediments  can  i s o b t a i n e d between these two elements  c o r r e l a t e s with T i i n the s i l l the  Ti  content.  sediments  by  the  to This  but i t s  simultaneous  plagioclases  (which  1966)) and the winnowing i s consistent  with  from the a n a l y s i s of the other  the major  elements. The central almost presence  excellent basin  would suggest t h a t ,  exclusively as  Goldschmidt,  c o r r e l a t i o n between T i and A l or Fe i n t h i s environment,  c o n t r o l l e d by c l a y  clay-size  T i C ^ Phases  1954). 200  minerals, i s also  i n the Ti is  although i t s  possible  (see  201  Some of the T i from  the  (section Ti/Al  amphiboles 4.3.1).  ratio The  present i n the s i l l which were  sediment c o u l d a l s o come  identified  in  these  samples  These m i n e r a l s tend t o have a r e l a t i v e l y  (e.g. Rankama and Sahama, 1950).  slope of the r e g r e s s i o n l i n e  in F i g .  44 suggests  the m i n e r a l phases which c o n t r o l the T i d i s t r i b u t i o n  i n the  basin  with  have  materials 1976).  a T i / A l ~ 0.083 which i s high compared  that deep felsic  (Rankana and Sahama, 1950; Spears and K a n a r i s - S o t i r i o u ,  This  may  reflect  dominate the Saanich area From  the  concluded equally  high  that  the v o l c a n i c o r i g i n of the rocks (Spears and K a n a r i s - S o t i r i o u ,  i n t e r c e p t on the A l a x i s at l e a s t  distributed  ( F i g . 44),  .1.2 wt % A l (or more i f  throughout  which  1976).  it  some  the anoxic sediments)  can  be  TiC^  is  must  be  c o n t r i b u t e d by an a l u m i n o s i l i c a t e which does not c o n t a i n T i (e.g. plagioclase),  thus  f e l d s p a r - A l present The that  at  anoxic  suggesting an upper l i m i t  of the F e - T i r e g r e s s i o n l i n e a l s o  1-1.5  sediments  of  i n these sediments.  intercept least  f o r the amount  wt % Fe must have been  as  oxides,  which  c o n c l u s i o n s p r e v i o u s l y drawn ( s e c t i o n  is  indicates  introduced in  accord  in  the  with  the  4.3.2.5).  4.3.2.3.7 CONCLUSIONS Due the  to the l a r g e u n c e r t a i n t i e s and s i m p l i f i c a t i o n s made  discussion  conclusions obtained  of the major elements,  drawn  from  are  tentative.  each of  However,  a l l the major element data 202  the the  suggests  in  individual consistency that  some  confidence their  be given to the general  picture  sill  sediments,  Satellite  dominated  by  Channel, quartz  particularly  present  in  plagioclase  are  characterized  by  a  lag  sediments  with a composition  can  be  of  deposit  and p l a g i o c l a s e which accumulates  these  main f e l d s p a r present the  from  i n the e a s t e r n branch  winnowing by r e l a t i v e l y strong t i d a l c u r r e n t s . Al  inferred  distribution. The  the  can  due  to  Up to 75% of  accounted  c l o s e to andesine,  for  the by  which i s  the  in the rocks of the Vancouver V o l c a n i c s and  S i c k e r S e r i e s that dominate the region ( s e c t i o n 4.2.3). is  a  remaining  Al  present  i n c l a y minerals  (mainly  chlorite)  and amphiboles which c o n t r o l the Fe,  Mg,  The  illite K,  and  and  Ti  d i s t r i b u t i o n s . The presence  of small q u a n t i t i e s of K - f e l d s p a r and  t r a c e s of T i oxides i s a l s o  likely.  The  sediments from the Cowichan Bay area have a  distinct contain have  from  the  more c l a y m i n e r a l s ,  significantly  consistent composed  r e s t of the s i l l  with  higher  They  particularly chlorite, Fe/K  the presence  mainly of c h l o r i t e ,  sediments.  and  Fe/Al  of metamorphosed  composition seem  since  ratios.  to they  This  volcanic  i n the S i c k e r S e r i e s (see  is  rocks, section  4.2.3). In  the  central  c o n t r o l l e d by o p a l , presence  basin,  the d i s t r i b u t i o n of S i  is  mainly  although X-ray d i f f r a c t i o n a l s o r e v e a l s  of some quartz and p l a g i o c l a s e . On  203  the b a s i s of t h e i r  the Ca  and  Na c o n t e n t s ,  could  be  up to 50% of the A l present i n these sediments  present  suggests  in feldspars.  However,  distribution of  the t o t a l A l . The Fe d i s t r i b u t i o n confirms t h i s l a s t estimate  and  since  indicates it  that  would r e q u i r e an u n r e a l i s t i c a l l y high  i t can be concluded  for  input  in clay minerals.  The  of  iron  of the A l p r e s e n t ,  the  (chlorite,  good c o r r e l a t i o n  remainder  illite  central  which  being  and probably  found between Fe and Mg  accounts  distributed kaolinite).  over the e n t i r e  suggests that these elements are e s s e n t i a l l y c o n t r o l l e d  the same phase,  most probably c h l o r i t e ,  1-1.5% Fe as oxides i s a l s o l i k e l y .  Na  Consequently,  sediments c o n s i s t s i n part of p l a g i o c l a s e , ~25%  unlikely,  that the l i t h o g e n o u s f r a c t i o n of the  between c l a y minerals  inlet  is  T h i s i m p l i e s that some of the Ca and  the c e n t r a l b a s i n must occur  basin  f o r more than  a much higher p r o p o r t i o n  oxides to the sediments. in  account  Ti  25%  further  that t h i s mineral cannot  the  by  although an a d d i t i o n of  Fe c o r r e l a t e s a l s o with K i n  the sediments of the c e n t r a l b a s i n . The main K-bearing m i n e r a l i n these  sediments  is  probably  p r o p e r t i e s s i m i l a r to c h l o r i t e , same  illite and  has  hydrodynamic  t h e r e f o r e accumulates  i n the  environments. The  nearshore  mineralogy  of  the  samples SAG11,  sediment  composition  adjacent . rock  SAG14,  SAG29,  would  be  expected  SAG33,  from the 204  tends to  lithologies.  shores of the i n l e t have d i s t i n c t i v e l y which  which  reflect For  the  instance,  and SAG41, on the eastern low Fe/K  weathering  and F e / A l residue  ratios, of  the  adjacent  granodiorite  diorite).  In c o n t r a s t , the nearshore  of Tod I n l e t Fe/K  and  batholith  and . C o l q u i t z sediments  gneiss  found at the mouth  show a d i s t i n c t i v e l y more mafic c h a r a c t e r ( i . e . high  Fe/Al)  r e f l e c t i n g the composition  of  the  V o l c a n i c s which are the main source rocks f o r these All  nearshore  and Ca/Al, also  (quartz  sediment  accumulation  by  sediments.  samples have r e l a t i v e l y high  r e f l e c t i n g the accumulation  characterized  Vancouver  high  of p l a g i o c l a s e .  Si/Al ratios  which  Na/Al  They are  indicate  the  of d e t r i t a l quartz ( s e c t i o n 4.3.2.3.2, F i g . 33).  4.3.2.4 PHOSPHORUS The is  very  c o n c e n t r a t i o n of phosphorus i n Saanich I n l e t low (Appendix  distribution apatite  pattern.  which  surrounding (correlation  IV-1) and does not show any Phosphorus probably occurs  i s present  rocks  as  (Clapp,  a  secondary  1913),  between %P and %C  and  sediments  well-defined in d e t r i t a l  mineral  in  in  organic  the  matter  : r = 0.65). org  4.3.2.5 SULPHUR The accumulation due  to  the  of sulphur i n marine sediments  precipitation  of  iron  sulphide  r e a c t i o n between d e t r i t a l i r o n and H S produced 2  activity is,  of s u l p h a t e - r e d u c i n g b a c t e r i a .  in part,  a l s o produced  sulphur s p e c i e s (see chap.  i s primarily  formed by the  Organic  by  metabolic  sulphur,  by d i a g e n e t i c r e a c t i o n s with 2),  a l s o accounts  205  the  which reduced  for a significant,  although g e n e r a l l y s m a l l e r , p r o p o r t i o n of the sulphur p r e s e n t . As  expected,  the  sulphur c o n c e n t r a t i o n i n  Saanich  sediments i s higher i n the c e n t r a l basin d e p o s i t s is  generally  There i s a  found throughout the sediment  correlation  between C  where f r e e  ( F i g . 46).  and S (r=0.78;  F i g . 47) i n  Berner, labile the  Such  1984)  a  organic matter used by sulphate reducers, produced,  2  deposited.  This  since  organic origin  r e l a t i o n s h i p has o f t e n been observed  and i s e x p l a i n e d by the f a c t that the  amount of H S  strong  3  and nearshore sediments which were d e p o s i t e d under  conditions.  covariation  the  detritus  oxic (e.g.  amount  and  of  therefore  i s p r o p o r t i o n a l to the t o t a l carbon i s not expected to be  p r o p o r t i o n of  labile  i s highly variable,  of the organic matter  F^S  column  org the s i l l  Inlet  particularly  materials  present  depending mainly  (Lyons and Gaudette,  in  on  the  1979) and  on  the extent of p r i o r o x i c d e g r a d a t i o n (Westrich and Berner, 1984). The  lower S/C  r a t i o o b t a i n e d i n these sediments ( c a .  47) compared to the average v a l u e s f o r "normal marine (0.33,  Berner  and  Raiswell,  1983) may  reflect  a  0.16;  Fig  sediments" significant  t e r r e s t r i a l component i n the organic f r a c t i o n of these samples. In  the  sediments from the c e n t r a l b a s i n ,  the % C g vs Q r  %S  c o r r e l a t i o n breaks down and c o m p a r a t i v e l y more sulphur i s present ( F i g 47).  T h i s i s a sulphur d i s t r i b u t i o n p a t t e r n commonly  i n anoxic environments 1984)  (e.g.  Berner and R a i s w e l l ,  1983; Berner,  i n which S accumulation depends more on Fe r a t h e r  a v a i l a b i l i t y . The tendency f o r a lower S/C 206  found  than  C  r a t i o i n the sediments  F i g . 4 6 : D i s t r i b u t i o n of sulphur. 207  1 -5H  t  • •• 1 .cH CO  0.5 • Central O S i II A S a nd  2  Basin  3 %C o rg  F i g . 47: C o r r e l a t i o n between %S and %C „ org I n l e t sediments. rt  208  i n Saanich  towards  the  head of the i n l e t  suggests the presence of a  amount of r e a c t i v e i r o n i n these  lower  samples.  4.3.2.6. MINOR ELEMENTS The by  a  d i s t r i b u t i o n of minor  wide range of environmental  s e c t i o n 4.1, their  p r e f e r e n t i a l accumulation,  significant  rock-forming lithogenous  the  minor  variables.  As  is  affected  discussed in  particularly  in  organic-rich  However, most of these elements a r e a l s o found c o n c e n t r a t i o n i n the l a t t i c e s of  minerals  which  constitute  f r a c t i o n of the sediments.  d i f f e r e n t minor the  i n sediment  i t has been argued that v a r i o u s f a c t o r s can l e a d t o  anoxic sediments. in  elements  constituents,  element  the  the  principal  bulk  of  the  D i f f e r e n t minerals  have  and t h e r e f o r e one must expect  that  d i s t r i b u t i o n w i l l be s i g n i f i c a n t l y a f f e c t e d by  mineralogy of the sediments  concerned.  The d i s t r i b u t i o n of the minor  elements amongst the d i f f e r e n t  rock-forming m i n e r a l s i s p r i m a r i l y determined by t h e i r a b i l i t y t o replace  a major c a t i o n  results  mainly from the s i m i l a r i t y  of  two  the  ions i n v o l v e d .  general p a t t e r n  K  +  chiefly  (e.g.  ability  i n s i z e and e l e c t r o n e g a t i v i t y  Thus i t i s p o s s i b l e  to  discern  1979). Some ions w i l l p r i m a r i l y  a  igneous  substitute  Rb , C s , B a , and P b ) , and t h e r e f o r e w i l l occur +  +  + +  + +  i n m i n e r a l s produced d u r i n g the late, stage of  crystallization readily  Such  i n the p a r t i t i o n i n g of t r a c e elements' i n  rocks (e.g. Krauskopf, for  i n a host c r y s t a l l a t t i c e .  ( K - f e l d s p a r s , m i c a s ) . Others w i l l  s u b s t i t u t e more  f o r Mg (Cr, Co, N i ) or Fe (Mn, V, T i ) and w i l l 209  magmatic  tend t o be  higher i n the mafic end of the c r y s t a l l i z a t i o n sequence ( i . e . i n olivine,  pyroxene,  hornblende).  They  c o n c e n t r a t i o n s i n u l t r a m a f i c rocks,  will  occur  b a s a l t s and  rocks melt  at  any  stage of the  in  which can separate  crystallization,  Also,  not s u b s t i t u t e  f o r any of the major elements and w i l l occur p r i m a r i l y as s u l p h i d e phases,  higher  gabbros.  some minor elements (e.g. Cu, Pb, Zn, Hg, Cd) w i l l readily  at  igneous from the  depending  on  the  sulphur c o n c e n t r a t i o n i n the magma. Consequently,  if  one  wishes  environmentally-controlled  enrichment  metals,  first  i t is  imperative  to  m i n e r a l o g i c a l c o n t r o l on the observed is  p a r t i c u l a r l y true i n the present  to  investigate  mechanisms determine  basin  the  mineralogy  study  of the anoxic  s i n c e both  extent  of This  mineralogy  a clear  sediments i n  (higher c l a y content with a more mafic  oxic c o u n t e r p a r t s from shallower  the  trace  distribution pattern.  and the d i s t r i b u t i o n of major c a t i o n s suggest between  for  the  distinction the  central  s i g n a t u r e ) and t h e i r  environments.  The minor element c o n c e n t r a t i o n s i n Saanich  Inlet  sediments  are r e p o r t e d i n Appendix IV-1. 4.3.2.6.1 RUBIDIUM AND BARIUM The  ionic  r a d i u s of Rb  (1.57 A) and  i t s electropositive  c h a r a c t e r make i t a p a r t i c u l a r l y s u i t a b l e c a t i o n f o r s u b s t i t u t i o n + ° for K ( i o n i c r a d i u s : 1.46 A ) . T h e r e f o r e , t h i s element w i l l be found  mainly  i n the K - f e l d s p a r s and micas,  210  and w i l l  occur  at  higher c o n c e n t r a t i o n A  good  sediments  in felsic  correlation  from  the  rocks.  between  c e n t r a l basin  i n t e r c e p t c l o s e to zero.  K and  Rb  (Fig.  48,  groups of samples can be d i s t i n g u i s h e d ( F i g . towards  within  the  Cowichan Bay,  r=0.96)  48), although  On the  sediments  suggesting environment reflecting  are a  the  an  lower  sill,  two  f o r the  central  found basin  they tend to be s l i g h t l y higher i n  l i e o u t s i d e the  that  with  49). On the western  potassium. On the other hand, the values obtained sill  i n the  most of the Rb/K r a t i o s are  2 (T range of values obtained  sediments ( F i g .  found  T h i s i n d i c a t e s t h a t , as expected, K and  Rb are c o n f i n e d to the same mineral phase(s).  sill,  is  2 0" boundaries,  Rb/K  significant.  f o r the eastern  This  values can  thus  recorded be  strongly in  this  interpreted  change i n the predominant K-bearing  as  mineral  from  both environments. I t has been reported that the Rb c o n c e n t r a t i o n is  generally  higher  i n micas than i n K - f e l d s p a r s  Sahama, 1950). The lower Rb/K r a t i o s obtained (Fig.  48)  (Rankama  and  on the e a s t e r n  sill  c o u l d t h e r e f o r e be due to the presence of  relatively  more K - f e l d s p a r s r e l a t i v e t o micas i n t h i s l a g d e p o s i t . consistent  with the occurrence  nearshore  sediments,  granodiorite be  of the lowest  particularly  those  This  Rb/K r a t i o s i n the adjacent  to  b a t h o l i t h where the i n f l u e n c e of K - f e l d s p a r s  expected t o be the s t r o n g e s t .  deep-sea  c l a y s (60-70 ppm/%,  supports  the occurrence  the would  The much higher Rb/K found  C a l v e r t and P r i c e ,  1977)  of a higher Rb/K r a t i o i n c l a y 211  is  in  further minerals  / /  /  1  0  1  —  1  1  '  0.5  '  '  I  I  I  I  1.0  I  I  I  I  1.5  %K  Fig.  48:  Correlation between I n l e t sediments.  212  K and Rb  in  I  Saanich  F i g . 49:  Distribution of the R b / K r a t i o . 213  compared of  to f e l d s p a r s .  Paria  K, +  i n the c l a y s of the Gulf  was a l s o r e p o r t e d and a t t r i b u t e d to  absorption However,  A Rb enrichment  of Rb  over K  +  p r i o r to  +  deposition  the low Rb/K r a t i o of seawater  Riley  and  Chester,  1971)  the  (Hirst,  (120 Xiq/l  would  argue  preferential  Rb ,  1962b). 416 mg/1  +  against  such  a  possibility. Barium minerals; that Ba  + +  also however  between  thus  (Krauskopf, The  to  that,  rock-forming  well-marked  producing  enter  rocks  barium  c o n c e n t r a t i o n i n the sediments of Saanich  Inlet  a  towards the head of the f j o r d  that i t i s mainly present  more d e t a i l e d a n a l y s i s of i t s  in  (Fig.  form  of barium  distribution  must a l s o be p r e s e n t .  proxies for K in aluminosilicates, sediments w i l l  reflect  50).  aluminosilicates.  This i s  shown when c o n s i d e r i n g the d i s t r i b u t i o n of Ba/K r a t i o s .  only  K  i n mafic  reveals  although not e n r i c h e d i n the o r g a n i c - r i c h sediments,  biogenic  the  potential,  early-crystallizing  a higher Ba/K r a t i o  as  1979).  indicates  However,  i s not as  in  Because of i t s higher i o n i c  preferentially  shows a gradual decrease This  f o r potassium  their co-variation  K and Rb.  tends  minerals,  substitutes  clearly Since Ba  an i n c r e a s e i n t h i s r a t i o  an a d d i t i o n a l source of barium.  has t h i s r a t i o higher values i n the nearshore  some  sediments  in Not in  which XRD and major elements a n a l y s i s suggested a higher f e l d s p a r concentration feldspars),  (presumably  because of a higher Ba/K r a t i o i n these  but i t has a l s o d i s t i n c t l y higher values towards the 214  F i g . 50: Distribution of B a . 215  F i g . 51: Distribution of the B a / K r a t i o . 216  2 0 0-.' 2  i  i  4  i  i  6  i  i  8  i  Si/Al Fig.  52:  C o r r e l a t i o n between Ba/K and S i / A l r a t i o s i n Saanich I n l e t sediments.  217  head of the i n l e t found  between  ( F i g . 51).  the  samples c o l l e c t e d 52).  This  Ba/K  input  indicates  there  not in  concentration  of Ba  present  in t h i s phase. typical The  an  an  lithogenous additional  increase  If we  This  t  concentrations  ^ ^/  phase  ( B a / K ) ^ ^ = c a . 366,  the data  data  is  S  opal  bio  A  l  ^nth  =  c a  x  x 3.5)]  concentration  218  used.  (Sancetta  and C a l v e r t ,  3  Ba/K  r a t i o s of  « '  (Fig.  5  l i t h  by, v i z )] x  (Ba/K)  2.14 l i t h  x  2.14  38.5 - (0.60  is  particulates  "  x (Si/Al)  - (3.51  ( p p m ) = [311  the  than i n  52) can be  from SAG3 g i v e , v i z  Ba  Ba  settling  of the S i / A l and  ( p p m ) = [Ba(ppm) - (%K  =  this  because  ( F i g . 98)). Hence, the opal and  %opal = [30.3  barium  from SAG3, which i s a  (Fig.  from  little  %opal = [%Si - (%A1 biQ  of  in  absolute  the Ba  i n sediments can be estimated  Ba  present  assume that the b i o g e n i c barium  collected  an estimate  Fig.  although  the  i t i s p o s s i b l e to estimate  samples,  aluminosilicate  (r = 0.92; Ba,  be  sediment  in t h i s b i o g e n i c phase i s not higher  For t h i s purpose,  provide  the  source  in  sediments.  c o l l e c t o r s which c o n t a i n very  The  c e n t r a l basin  sample with a high opal content  winter  1987),  and  of  l i n k e d to o p a l i n e s i l i c a ,  these  phase.  in opal,  is  produce  concentration  the l i t h o g e n o u s  the S i / A l r a t i o s  that besides  or i n d i r e c t l y does  and  from the s i l l  aluminosilicates, directly  Moreover, a good c o r r e l a t i o n can  x 366)]  = 95  )]  the 87);  biogenic  Ba  which correspond to a barium c o n c e n t r a t i o n of c a .  250 ppm i n the  o p a l i n e s i l i c a . T h i s value i s of the same order than the estimate given by Dehairs et a l . (1980). There  i s however  distribution  another  possible  of Ba i n Saanich I n l e t sediments.  microflagellate  algae  c o u l d be the main conveyor  in  r a t h e r than  of Ba to marine sediments  waters  only.  Such  due t o higher s t r a t i f i c a t i o n of the water column.  reflect  Ba/K an  ratios input  found i n the inner of b a r i t e from such  a s s o c i a t i o n of Ba with o p a l i n e s i l i c a  diatoms  are more  where a lower  primary p r o d u c t i o n has been measured ( C a l v e r t ,  higher  diatoms,  ( C a l v e r t and  conditions  f r e q u e n t l y met towards the head of the i n l e t , of  of  1979),  1983). These micro-algae are able to compete with  nutrient-depleted  the  Some s p e c i e s  ( F r e s n e l et a l . ,  i t has been suggested that such algae,  Price,  to  (e.g. Pavlova sp.) are known to c o n t a i n  b a r i t e m i c r o - c r y s t a l s i n t h e i r cytoplasm and  explanation  fjord  unpublished), T h e r e f o r e , the  sediments  algae,  rate  rather  (see a l s o s e c t i o n  could  than  an  4.4.3.1).  4.3.2.6.2 STRONTIUM Strontium can r e p l a c e both K and Ca i n m i n e r a l l a t t i c e s . The analysis  of  Saanich  I n l e t sediments  reveals  a  rather  strong  c o r r e l a t i o n between Ca ( c o r r e c t e d f o r carbonates) and Sr i n most of  the sediment  samples ( F i g .  53). However,  breaks down i n some nearshore sands, to  the g r a n o d i o r i t e b a t h o l i t h ,  this  particularly  relationship  those adjacent  which are r e l a t i v e l y poor  219  i n Sr  • C e n t r a l O S i II  100  A  0  1.0 % Ca  B a s i n  S a n d  2.0  3.0  ( non - c a r b o n a t e )  F i g . 53: C o r r e l a t i o n between Sr and Ca i n Saanich I n l e t sediments.  220  compared  to  primarily  l i t h o g e n o u s Ca.  held  in  Strontium seems  the p l a g i o c l a s e f e l d s p a r s ,  relatively  e n r i c h e d in the nearshore  exception  of  granodiorite. inlet  those  collected  The constant Sr/Ca  ( i n the c e n t r a l b a s i n ,  the  in  the  andesine The  Volcanics  sill,  and many  probably  reflect  with  rock  4.3.2.2,  the  limestone  distinctly  main  characterized estimated A  by  of  the  types,  a  at  presumably  which  contain  (Clapp,  1913).  Sr/Ca  values,  lower  i n the  ratio.  i n Saanich  Bamberton.  relatively  Ca-  As d i s c u s s e d i n s e c t i o n  source of carbonate situated  areas)  Inlet  This  low Sr/Ca  ratio  is  limestone which  can  a is be  i n the f o l l o w i n g manner.  linear  collected  the  the i n f l u e n c e of the p l a g i o c l a s e present  i s a l s o present i n CaCO^.  quarry  is  nearshore  Series  g r a n o d i o r i t e which probably has a d i f f e r e n t Strontium  such  (and p o s s i b l y other  and the S i c k e r  samples,  be  with  proximity  as one of the p r i n c i p a l m i n e r a l phases  nearshore  to  r a t i o obtained over most of the  phases) o r i g i n a t e d from s i m i l a r  Vancouver  and as  sands (Table 37)  suggests that t h e i r p l a g i o c l a s e component bearing  therefore  in  regression the  of S r / A l vs  c c  a  r  j % 3  zone of i n f l u e n c e of the  in  the  quarry  sediments yields  the  sediments  is  equation, v i z Sr/Al Since  the  approximately C  carb  (ppm/%) =5.6 Al  4.5%,  P °duce an r  C  c a r b  concentration it  %  + 35 in  can be concluded  increment  (r=0.93) these  that an a d d i t i o n of  of ~25ppm Sr. Thus the  221  1%  limestone  Table 37: in  Average S r / A l  the  different  sediment  present  ratios  types in  of  Saanich  Inlet. Sr/Al Nearshore sediments  56+7  Eastern  sill  42+1  Central  basin  33 + 7  222  has  a Sr/Ca ~0.3X10  .  In c o n t r a s t ,  the s h e l l  fragments  were present  i n the SAG 51 sample produced  an increment  Sr  ,  ratio  per % C  c a r b  corresponding t o a Sr/Ca  which  of ~255ppm  i n the  carbonate  -3  phase  of  approximately  (Goldschmidt,  3x10  which i s t y p i c a l  of  aragonite  1954).  4.3.2.6.3 NICKEL AND CHROMIUM The d i s t r i b u t i o n of n i c k e l and chromium i n igneous generally  related to the d i s t r i b u t i o n of Mg and Fe 2+ ° 1979). Ni ions have an i o n i c r a d i u s (0.77 A) c l o s e 2+ o  to t h a t of Mg  (0.80 A),  thus a l l o w i n g a d i a d o c h i c s u b s t i t u t i o n  in the l a t t i c e of Mg-bearing m i n e r a l s Similarly,  Cr  distribution  can  can s u b s t i t u t e  of  this  element  f o r Mg  (Rankama and Sahama, 1950). and Fe  i s further  r e a d i l y form independent of  .  However,  complicated  t o undergo o x i d o - r e d u c t i o n r e a c t i o n s .  members  is  closely  (Krauskopf,  ability  rocks  by i t s  When o x i d i z e d , i t  chromium m i n e r a l s ,  the s p i n e l group which o f t e n occur  the  mainly  chromian  i n basic  rocks  (Rankama and Sahama, 1950). In Saanich I n l e t , diatomaceous 54). higher  n i c k e l shows a d i s t i n c t enrichment  i n the  ooze of the c e n t r a l basin and i n Cowichan Bay ( F i g  However, content  s i n c e these sediments of  mafic  further  minerals  (section this  4.3.2.3),  necessary  to  concluding  that an e n v i r o n m e n t a l l y - c o n t r o l l e d Ni  occurring. The correlation  investigate  are a l s o c h a r a c t e r i z e d by a  distribution  before  enrichment  between Ni and Mg over the e n t i r e 223  i t is  is  inlet,  F i g . 5 4 : Distribution of Ni. 224  which  would  be  expected i f the Ni d i s t r i b u t i o n  c o n t r o l l e d by the mineralogy of the sediment,  was  primarily  i s very poor ( F i g .  55,  r=0.24). However, the three sediment  and  c e n t r a l basin) can be c l e a r l y d i s t i n g u i s h e d on t h i s  The  h i g h e s t Ni/Mg r a t i o s are found i n the anoxic  the  lowest  in  the nearshore sands,  i n t e r m e d i a t e v a l u e s . Moreover,  within  each  particularly less  f o r the s i l l  organic matter.  sediments  has  superimposed is  these " p r o v i n c e s "  a  more  significant, contain  the r e g r e s s i o n l i n e f o r the  a very l a r g e i n t e r c e p t .  anoxic  A l l t h i s suggests  nickel  enrichment  associated  i n the c e n t r a l b a s i n .  with  the  that, there  conditions  of  T h i s i s more c l e a r l y shown  Fig.  56 where Ni/Mg r a t i o s are p l o t t e d a g a i n s t %  very  clear  Such  a  c o r  r e l a t i o n s h i p i n d i c a t e s that e i t h e r  in  g « There i s a  i n c r e a s i n g t r e n d of Ni/Mg i n o r g a n i c - r i c h  d i r e c t l y a s s o c i a t e d with o r g a n i c matter,  sediments.  the "excess N i " i s  or that the environment  d e p o s i t i o n i s conducive to the simultaneous accumulation of Ni  and  organic  increase their  oxic  Moreover,  Fig  56 shows  that  the  accentuated i n the anoxic sediments  counterparts.  This  mechanism s p e c i f i c a l l y  involved,  fraction  matter.  i s more  enrichment is  coefficient  and nearshore sediments which  Also,  and  sediments  on a m i n e r a l o g i c a l l y - c o n t r o l l e d d i s t r i b u t i o n ,  deposition  of  sill  the r e g r e s s i o n  i s much  figure.  sediments  while the  display  of  types (nearshore, s i l l ,  suggests  either  than  that  l i n k e d with anoxic  accumulates  in 225  low-carbon,  in  another  conditions  or that Ni i s s l i g h t l y e n r i c h e d i n a heavy  which  Ni/Mg  mineral  coarser-grained  0  0.5  1.0  1.5  2.0  %M g  Fig.  55: C o r r e l a t i o n between Ni and Mg I n l e t sediments.  226  i n Saanich  •  ioj  C e n t r a l  B a s i n  O S i II A  I  I  1  I  I  I  2  I  S a n d  I  3 %C org  Fig.  56: R e l a t i o n s h i p between Ni/Mg and %C Saanich I n l e t sediments.  227  in g  sediments. I t seems w e l l - e s t a b l i s h e d however, that Ni i s e n r i c h e d in o r g a n i c - r i c h The not  chromium d i s t r i b u t i o n  show  central  sediments.  any  (Fig.  correlation  with Mg  considered,  implies  the  57).  Moreover,  (r=0.63), that  minerals  distribution. from  is  When  its  r=0.94),  suggested  for  sediments.  only  factor  the  central  concentrations sediments.  a  basin,  are  This  nickel  relatively is  clearly  an  (Fig. org  c o n t r o l mechanism s i m i l a r  to the  its  samples  i s obtained between Cr/Mg and %C  contrast  are and  controlling  Ni whereby Cr would be e n r i c h e d  In  poor  i t s presence i n the l a t t i c e of Mg not the  indicating  the  samples  3  58,  in  c o n s i d e r i n g only the anoxic sediment  correlation  does  relatively  when a l l the sediment  southern and e a s t e r n p a r t of  excellent  sediments  c l e a r evidence f o r a chromium enrichment  basin  Fe-bearing  i n Saanich I n l e t  in  3  to  that  organic-rich  distribution,  chromium  high  in  nearshore  and  shown  in  Fig.  where  59  sill the  d i s t r i b u t i o n of "excess Cr" ( c a l c u l a t e d by s u b s t r a c t i n g the Cr/Mg ratio  expected  from  the  r e g r e s s i o n data from F i g .  organic 58,  carbon  content,  using  the  from the Cr/Mg a c t u a l l y measured)  i s mapped. The l a r g e s t excess i s found i n the e a s t e r n part of the Satellite  Channel  accumulation distribution similar  of  where r e l a t i v e l y high t u r b u l e n c e heavy  strongly  minerals  (Section  suggests the presence of  4.3.2.3). chromite  m i n e r a l i n these sediments and i n most of the  environments.  The  favors  This or  a  nearshore  presence of t h i s mineral would not be 228  the  totally  F i g . 5 7 : Distribution of C r . 229  %c o Fig.  58:  r  g  C o r r e l a t i o n between Cr/Mg and %C Saanich I n l e t sediments.  230  in g  F i g . 59: D i s t r i b u t i o n of " e x c e s s " C r . 231  unexpected,  since  olivine-rich  it  i s known to be r e l a t i v e l y common  inclusions  in  found i n b a s a l t i c rocks (Deer  the  et a l . ,  1 966) . In c o n c l u s i o n , while both n i c k e l and chromium are present i n Fe and Mg-bearing central these  basin, two  there  metals  distribution also  m i n e r a l s which accumulate  i s evidence f o r a f u r t h e r  i n the  anoxic  of the two elements  enriched  accumulation  in of  preferentially  lag  i n the  enrichment  organic-rich  sediments.  d i f f e r s however i n that  deposits,  presumably  because  chromite or s i m i l a r minerals d e r i v e d  in The  Cr  is  of  the  from  the  nearby b a s a l t i c r o c k s . 4.3.2.6.4 VANADIUM AND Vanadium  (V ^, +  MANGANESE V , + 4  and V ^) +  and Mn  (Mn ) +2  are  strongly  e n r i c h e d i n b a s i c rocks, and are o f t e n found to c o r r e l a t e with Fe and Mg  (Krauskopf,  1979).  Vanadium shows a d i s t i n c t Saanich  I n l e t and  enrichment  i n Cowichan Bay  (Fig.  i n the c e n t r a l basin of 60).  Furthermore,  good c o r r e l a t i o n with Ni i n the c e n t r a l basin and s i l l (Fig.  61,  r=0.89)  controlling  the  environments. %C  org  (Fig. 3  organic-rich sands  suggests  distribution  This 62)  closely  that  a s i m i l a r mechanism  of these two  elements  its  sediments may in  these  i s again c l e a r l y shown on a p l o t of V/Fe which i n d i c a t e s a vanadium enrichment  c e n t r a l b a s i n sediments.  Moreover,  the  be  in  vs the  nearshore  seem to be the s i t e f o r the accumulation of a V - r i c h heavy  mineral.  Fig.  61 a l s o shows a good c o r r e l a t i o n between Ni and V 232  F i g . 60: Distribution of V. 233  2 501  2004  £ a.  15  0-1  Q.  1 00-i  50-1  0  •  C e n t r a l  B a s i n  O S i 1 1 A S a n d  10  I  20 ppm  30  I  40  Ni  F i g . 61: C o r r e l a t i o n between sediments.  234  I  V and Ni i n Saanich I n l e t  235  in  the nearshore  is  c o n t r o l l i n g both elements i n these The  samples (r=0.90),  distribution  samples.  of manganese a l s o shows an enrichment  the c e n t r a l b a s i n sediments. erratically distributed, (Fig.  suggesting that the same phase  Some high Mn v a l u e s (>900 ppm) seem  mainly  i n the c e n t r a l p a r t of the i n l e t  63). The three sediment types  (nearshore, s i l l  ooze) can be r e a d i l y d i s t i n g u i s h e d on a Mn/Fe vs % 64).  The  increase with to  anoxic  oozes  tend to have  however v a r i e s e r r a t i c a l l y  organic  carbon,  carbonate  high  (there are  carbon,  fairly  content  constant throughout  observed,  thus  o r  and anoxic  g  no  plot (Fig.  ratios.  the range  (Fig.  of  process.  Finally,  seems  65). The  low Mn/Fe which organic  c o n f i r m i n g that organic matter  i n v o l v e d i n the enrichment  The  correlations  or sulphur) and  sediments are c h a r a c t e r i z e d by a r e l a t i v e l y  stays  c  Mn/Fe  be c o n f i n e d t o the southern h a l f of the i n l e t  sill  in  carbon i s not  the nearshore  sands  are  d i s t i n g u i s h e d by a r e l a t i v e l y higher Mn/Fe r a t i o .  Since  and  V  in  (and t h e r e f o r e  Ni) covary t o a l a r g e  extent  sediments ( F i g . 66, r=0.91), i t may be concluded to  the  accumulation  enriched  in  covariation enriched sill,  these with  of a three  chromium  heavy  elements. (r=-0.20),  i n the l a g d e p o s i t present  implies  that  mineral  relatively  complete  which  these  that t h i s i s due  fraction  The  Mn  is  lack  of  principally  i n the e a s t e r n part  of the  a d i f f e r e n t mineral i s c o n t r i b u t i n g to i t s  distribution. Carbonate  precipitation  i s a mechanism whereby Mn c o u l d 236  be  F i g . 6 3 : Distribution of Mn. 237  •  400•  Central  Basin  O Si1 1 A Sa n d i.  •  300  • • • • • • • • • • • • •• • •  0 LL  200  * /  \*  ( oo ^ o 0  1 00  1  )  1  oo  2  3 %C  Fig.  64:  4  •  ••  5  o r g  R e l a t i o n s h i p between Mn/Fe and %C Saanich I n l e t sediments.  238  in g  F i g . 65: Distribution of the M n / F e ratio. 239  A  A  I  200  0  400  Mn  ppm Fig.  66:  Correlation sands.  600  between  240  Mn and V i n  nearshore  concentrated 1980;  in anoxic  Pedersen  and  sediments ( L i et a l . ,  Price,  1982).  It  1969;  requires,  Klinkhammer, however,  the  exceed  the  2+ presence  of  solubility  enough product  concentration  Mn of  in  the pore  rhodochrosite  to  (Johnson,  1982).Such  c o u l d only be a t t a i n e d i f enough Mn  the sediment s u r f a c e . In Saanich only  waters  I n l e t , such an  a f t e r a e r a t i o n of the water column.  oxides  a  reach  input i s p o s s i b l e  There are  indications  that during the f l u s h i n g of the i n l e t very oxides these  l a r g e q u a n t i t i e s of Mn 2+ are produced by the o x i d a t i o n of Mn (Grill, 1982). If oxides sink i n t o the anoxic sediment (see also section 2+  4.4.3.6),  they w i l l be reduced, thus i n c r e a s i n g l o c a l l y the  concentration  to values which c o u l d p o s s i b l y exceed Mn  Mn  carbonate  solubility. 4.3.2.6.5 ZINC AND  LEAD  Zinc i s p r i n c i p a l l y a c h a l c o p h i l e element However, i t s a f f i n i t y with sulphur other  transition  metals,  and  (Krauskopf,  1979).  i s l e s s prominent than that of  the amount of Zn found  in  early  magmatic s u l p h i d e s i s r e l a t i v e l y low. Because of t h e i r s i m i l a r i t y 2 2 ^* 2 in i o n i c s i z e , Zn can s u b s t i t u t e f o r Fe and Mg . Therefore, amphiboles,  pyroxene,  and  igneous rocks  (Rankama and  In  Inlet,  Saanich  c e n t r a l basin  (Fig.  67)  b i o t i t e are the main z i n c c a r r i e r s i n Sahama, 1950).  z i n c shows a higher which f a l l s again  southernmost part of the i n l e t vs %C  org  concentration  in the  to lower values  i n the  ( F i n l a y s o n Arm).  A p l o t of  shows a c l e a r i n c r e a s e i n Zn with organic matter 3  241  Zn/Fe without  F i g . 67: D i s t r i b u t i o n of Z n . 242  an  indication  conditions provinces  of  a  preferential  68).  However,  are r e l a t i v e l y depleted  due  readily  chiefly is  sediment  the sediments from F i n l a y s o n In c o n t r a s t ,  high Zn values  Arm are  Quarry,  to a s i g n i f i c a n t c o n c e n t r a t i o n of t h i s element in  limestone. Although  it  i n Zn.  anoxic  f o r the sediments c o l l e c t e d near the Bamberton  presumably the  under  as the l i n e a r r e l a t i o n holds f o r the three (Fig.  obtained  accumulation  l e a d i s a l s o c o n s i d e r e d a c h a l c o p h i l e metal,  forms s u l p h i d e m i n e r a l s ,  in K-bearing  relatively  minerals  e n r i c h e d in  i t occurs  since  in igneous  rocks  such as K - f e l d s p a r s and micas  acidic  rocks.  and  Notwithstanding  the  marked  d i s s i m i l a r i t y between the chemical p r o p e r t i e s of lead and ++ ° potassium, Pb (ionic radius: 1.26 A) seems able to s u b s t i t u t e + ° for K (ionic radius: 1.46 A) i n rock-forming m i n e r a l s (Rankama and  Sahama, 1950; As  Krauskopf,  for zinc,  1979).  the l e a d d i s t r i b u t i o n shows the presence of  s i g n i f i c a n t l y higher c o n c e n t r a t i o n i n the c e n t r a l b a s i n , with apparent d e p l e t i o n i n F i n l a y s o n Arm of  Pb/K  vs %  c o r  g  (Fig.  b e a r i n g m i n e r a l s and  anoxic  70  sediments.  obtained ooze  Fig.  organic matter  suggests In  69).  (or an a s s o c i a t e d f a c t o r )  i n Saanich  sediment.  an  A plot  70) c l e a r l y shows the importance of  e x p l a i n i n g the Pb d i s t r i b u t i o n however,  sediments ( F i g .  a  Unlike  Kin  zinc,  a p r e f e r e n t i a l Pb enrichment in. the  t h i s case,  the negative  Pb/K  intercept  by e x t r a p o l a t i n g the r e g r e s s i o n l i n e drawn through  samples (not c o n s i d e r i n g F i n l a y s o n Arm 243  sediments)  the  supports  s  v  v  Bamberton Quarry  501  Fnlayson Arm  •  Central Sill 0 A Sand  10  i  0  2  68:  i  3  %C  Fig.  Basin  o r g  Relationship between Zn/Fe and %C in org Saanich I n l e t sediments.  244  F i g . 6 9 : Distribution of Pb. 245  Fig.  70:  Relationship between Pb/K Saanich I n l e t sediments.  246  and %C  in g  the  view  that  at  least  some  of  the  Pb  has  been  added  independently of the organic matter. There  i s a l s o a very s i g n i f i c a n t Pb contamination a s s o c i a t e d  with the a c t i v i t i e s of the Bamberton Quarry  ( F i g . 70).  I t can t h e r e f o r e be concluded that Zn and Pb are e n r i c h e d i n the  o r g a n i c - r i c h sediments from the c e n t r a l b a s i n .  the  data suggest that Pb i s a d d i t i o n a l l y c o n c e n t r a t e d through  process  d i r e c t l y l i n k e d t o anoxic c o n d i t i o n s  precipitation). rationale Arm. in  samples  the i n l e t  35).  i s however  represent  Moreover,  the  If  the  in  1964).  a  Finlayson found  They have the h i g h e s t  significant  inlet  is  and d u r i n g years of weak f l u s h i n g  it  1965:  enrichment  U.B.C. Oceanography Data process  from the water column,  in such an environment  were  sediments. the  to  a s t r o n g e r metal  i s observed.  be r e a d i l y e x p l a i n e d by a v a r i a t i o n sediments.  due  Report, sulphide  enrichment  would be expected. On the c o n t r a r y , a very  Zn and Pb d e p l e t i o n  distributions  from  present  water column i n t h i s part of the  more i s o l a t e d ,  precipitation  these  to  sulphide  the most reducing sediments  (Gucluer and Gross,  may not be renewed (e.g.  cannot  difficult  a  carbon content and the lowest sedimentation r a t e s (Table  relatively  1966).  more  (possibly  f o r the behaviour of these two elements  These  organic  It  Furthermore,  The  K/Al  (Fig.  34)  Such a  discrepency  i n the mineralogy and  Fe/K  show a r e l a t i v e potassium d e p l e t i o n  of  ( F i g . 43)  i n these  same  T h i s i s thought t o r e f l e c t an input of mafic m i n e r a l s Goldstream R i v e r catchment 247  area.  Such a source  would  contain  K-bearing m i n e r a l s formed  sequence.  Such  r e l a t i v e to K observed  explain  Moreover,  anomaly.  If  a  such as V,  component  r u l e d out,  Cr,  Arm  environment.  i s the  Mn,  element  minerals which shows control  were  and N i . Consequently,  i n these sediments cannot  study  a be  different completely  that the d e p l e t i o n of Pb and  is  necessary  to  patterns  r e f l e c t s t h e i r geochemical behaviour  Further  Pb  e x p l a i n the  only  to the presence of  i t seems more l i k e l y  Finlayson  more  one would expect s i m i l a r  p o s s i b l e e f f e c t due  lithogenous  zinc  a mineralogical  such a d i s t r i b u t i o n ,  although  crystallization 2+  and t h e r e f o r e cannot  present i n Fe- and Mg-bearing  with other elements,  in  1979)  Pb d i s t r i b u t i o n .  depletion  the  would be expected to c o n t a i n  (Krauskopf,  +  predominantly this  phases  early in  to  in  Zn this  clarify  these  processes. 4.3.2.6.6 COPPER 2+ Although Cu may copper  present  minerals  are  solution.  present  Fig.  i n mineral  Sahama,  1950;  structures,  occurs  Krauskopf,  o x i d i z e d d u r i n g weathering and C u Therefore,  very  l i t t l e Cu i s  in  + +  is  (Fig.  obtained  the  sulphide  1979). is  These  released  expected  to  be  materials.  i s s t r o n g l y e n r i c h e d i n the c e n t r a l b a s i n  i n Cowichan Bay 72)  2+  rocks c h i e f l y  in lithogenous d e t r i t a l  Copper and  igneous  (Rankana and  sulphides into  in  r e p l a c e Fe  71).  A very good c o r r e l a t i o n  between  248  Cu/Mg and  %C  in  sediments (r=0.96, sill  and  F i g . 71: Distribution of C u . 249  I  I  I  I  2  I  3  I  I  4  I  I  I  5  %C org  Fig.  72: R e l a t i o n s h i p between Cu/Mg and %C Saanich I n l e t sediments.  250  in  Q g  nearshore  samples and anoxic oozes d e p o s i t e d towards the s i l l of  the i n l e t . content  of  expected  the  from  indicated (i.e.  Southward,  content)  anoxic sediments  i n F i n l a y s o n Arm, the Cu  i s in  large  t h e i r o r g a n i c carbon c o n t e n t s .  on F i g .  Cu/Mg  and p a r t i c u l a r l y  i s shown.  accumulation  of  Cu  environment,  i . e lower  that  clearly  of  "excess  Cu/Mg"  - Cu/Mg deduced from the  organic  carbon  This d i s t r i b u t i o n under  This  to  is  73 where the d i s t r i b u t i o n  measured  excess  suggests a  the c o n d i t i o n s  prevailing  in  this  and  predominantly  i n t e n s e l y anoxic c o n d i t i o n s ,  p o s s i b l y by s u l p h i d e  precipitation  (Jacobs and Emerson,  F i g . 72 a l s o suggests that only c a .  25%  sedimentation r a t e s  preferential  1982).  of the Cu present i n F i n l a y s o n Arm sediments  i s held  within  mineral l a t t i c e s . 4.3.2.6.7 MOLYBDENUM On average, the  earth's crust  high  charge  substitute  a c o n c e n t r a t i o n of c a . (Krauskopf,  1979).  and l a r g e i o n i c r a d i u s ,  1.5 ppm Mo i s found  in  Because of i t s r e l a t i v e l y molybdenum cannot  readily  f o r any of the major c a t i o n s present i n the  lattices  of a l u m i n o s i l i c a t e s . incompatible elements,  I t accumulates,  along with other s i m i l a r l y  i n the l a s t d i f f e r e n t i a t e s  produced d u r i n g  magmatic c r y s t a l l i z a t i o n , and consequently i s found i n r e l a t i v e l y higher where  concentration i n acidic i t occurs  Krauskopf,  mainly as  rocks,  MoS  2  and p a r t i c u l a r l y  (Rankama  and  granite  Sahama,  1950;  1979).  The molybdenum content of Saanich I n l e t 251  sediments  deposited  Fig. 73: Distribution of " e x c e s s " C u . 252  on  the  limit  sill (3  and i n nearshore  ppm).  concentration  In  environments i s  contrast,  in  the  below  anoxic  oozes,  very  (1967),  strong Mo enrichment  and  the  Calvert, largest  1974; Jones,  anoxic  1974;  ( F i g . 74). Gross  environments  P i l i p c h u k and Volkov,  1976). Among the minor elements,  enrichment  Mo  inlet  has a l s o been r e p o r t e d by  i s i n v a r i a b l y a s s o c i a t e d with  ( B e r t i n e and Turekian, 1974;  the  g r a d u a l l y i n c r e a s e s towards the head of the  and reaches values of up to 128 ppm i n F i n l a y s o n Arm This  detection  molybdenum shows  i n the anoxic sediments  compared  with  lithogenous d e b r i s . 4.3.2.6.8 ZIRCONIUM L i k e molybdenum, does  not  z i r c o n i u m i s an incompatible element which  r e a d i l y s u b s t i t u t e f o r any major  aluminosilicates enriched  in  processes  where i t i s mainly  zircon  the  (Krauskopf,  (ZrSiO^).  (Rankama  and  last  Consequently,  crystallization  products  1950),  although  and thus tends t o  i t can be found  zirconium d i s t r i b u t i o n  materials the s i l l  i t becomes of  igneous  weathering  accumulate  in a l l size (Hirst,  in  grades, 1962b).  i n Saanich I n l e t sediments shows  a d i s t i n c t i v e l y higher c o n c e n t r a t i o n i n the s i l l 75). T h i s probably r e f l e c t s  in  r e s t r i c t e d t o the a c c e s s o r y mineral  and t h e r e f o r e a l s o be present with c l a y m i n e r a l s The  present  T h i s m i n e r a l i s very s t a b l e d u r i n g  Sahama,  d e t r i t a l deposits,  1979).  element  sediments ( F i g .  d i l u t i o n by b i o g e n i c and a u t h i g e n i c  i n the c e n t r a l b a s i n . Since Z r / A l r a t i o s of sediments (av.  22.7 +2.3, n=12, 253  10") are s l i g h t l y higher  Fig. 74: Distribution of Mo. 254  Fig. 75: Distribution of Zr. 255  than i n the c e n t r a l b a s i n (av. indicate  a  preferential  18.0 +1.1,  accumulation  n=26,  10"), t h i s may  of z i r c o n  in  the  sill  sediment. 4.3.2.6.9 CONCLUSIONS While  the d i s t r i b u t i o n of Ba,  Rb, S r , and Zr i s e s s e n t i a l l y  c o n t r o l l e d by the mineralogy  of the sediments,  most  reflects  transition  metals  their  the behaviour biophilic  of  and/or  c h a l c o p h i l i c nature and d i s p l a y s a much more complex p i c t u r e . All show  the  a  lattice-held fraction.  Zn), t h i s  association  i n the c e n t r a l b a s i n ,  Mo)  additional  source,  to  after  explain  and  linked  i n the i n l e t ,  to  V,  direct  indirect  (Pb, Cu, and the  anoxic  i s c l e a r l y needed.  ( i . e . w i t h i n the organic matrix,  (e.g. adsorbed  from  conditions  on f i n e - g r a i n e d sediments a s s o c i a t e d with  can be due t o s u l p h i d e  explain  under either Lower  r a t e s o c c u r r i n g towards the head of Saanich  w i l l enhance the importance help  precipitation  the water column or a t the sediment/water i n t e r f a c e .  sedimentation  can be  or adsorbed) or  higher organic carbon c o n c e n t r a t i o n ) . A d d i t i o n a l enrichment anoxic  Cr,  enrichment  The a s s o c i a t i o n of these elements with o r g a n i c matter either  Mo)  correction  the  while i n other cases directly  c o n d i t i o n s which o f t e n develop  Mn  In some i n s t a n c e s ( N i ,  seems  observed an  (except  strong c o r r e l a t i o n with organic matter  for t h e i r and  t r a n s i t i o n elements analyzed  of t h i s second  possibility,  the s i g n i f i c a n t l y higher Cu and Mo  256  and  Inlet may  concentrations  found i n t h i s part of the 4.3.2.7 IODINE AND The  inlet.  BROMINE  c o n t r a s t i n g geochemical behaviour of these two  in marine  sediments  elements  i s w e l l documented ( P r i c e and C a l v e r t ,  1977).  The r e l a t i o n s h i p between bromine and o r g a n i c carbon i s i n v a r i a b l y l i n e a r and i s not a f f e c t e d by the redox regime of the of  deposition,  while  environment  i o d i n e i s comparatively e n r i c h e d  s u r f a c e s of sediments d e p o s i t e d under o x i c c o n d i t i o n s  at  (see  the Chap.  3). Analyses  obtained  from  Saanich  o b s e r v a t i o n s . There i s an e x c e l l e n t and  %  c o r  g  throughout the  intercept not  inlet  c l o s e to the o r i g i n ,  Inlet  confirm  these  l i n e a r c o r r e l a t i o n between Br (r=0.97,  Fig.  76),  with  an  thus c o n f i r m i n g that bromine  is  a f f e c t e d by redox chemistry and i s e n t i r e l y a s s o c i a t e d  the o r g a n i c matter.  On the other hand,  the r e l a t i o n s h i p between  iodine  and o r g a n i c carbon  impact  of the redox p o t e n t i a l on i o d i n e geochemistry.  oozes  from  the  i s much more complex and r e f l e c t s  c e n t r a l basin have a  r a t i o s than the nearshore sands,  with  significantly  while the s i l l  the  The black lower  sediments  I/C yield  intermediate v a l u e s ( F i g . 77 and 78). T h i s i s c o n s i s t e n t with the presence  of a mechanism whereby i o d i n e i s added t o the  sediments under oxic c o n d i t i o n s . detail  i n chapter 3.  257  surficial  T h i s phenomenon i s d i s c u s s e d i n  258  Fig. 77: Distribution of the I/C 259  ratio.  o r g Fig.  78:  Correlation between I I n l e t sediments.  260  and %C  ° ^  i n Saanich  4.4  ELEMENTAL  FLUXES  IN  SAANICH INLET  FROM  AUGUST  1983  TO  SEPTEMBER 1984 The are  elemental  f l u x e s measured a t the s t a t i o n s SI-9 and SN0.8  shown i n Appendix IV-3. Some  and  seasonal  flushing  of  events, the  such  as freshwater  inlet,  are  p a r t i c u l a t e f l u x e s i n the i n l e t .  likely  discharge  to  influence  run-off  interest  from the Cowichan River during  i s shown i n F i g .  79.  was very  small during  rose  abruptly  t o a maximum i n mid-November.  peak  input  l a t e summer and e a r l y f a l l  i n e a r l y January,  into  of the  1983, and  There was a  followed by a  of  data.  the p e r i o d  The fresh-water  inlet  lesser  the  An e v a l u a t i o n of the timing  these events would t h e r e f o r e h e l p to i n t e r p r e t the f l u x The  peaks  general  second  downward  t r e n d throughout s p r i n g . By mid-June and through summer, very low values  were again  region  (e.g.  observed.  Such a p a t t e r n  Herlinveaux,  1962),  i s typical  closely  of  this  following  the  precipitation. Another comes  important source of f r e s h water i n t o Saanich  from the F r a s e r R i v e r .  r i v e r are not a s s o c i a t e d with linked  to  the  snow-melt  The discharge  variations  the p r e c i p i t a t i o n p a t t e r n ,  i n the Coast  Ranges.  t h e r e f o r e a t i t s maximum i n June and J u l y ( F i g . c a r r i e s l a r g e q u a n t i t i e s of f i n e sediment. the  inlet  (Waldichuk,  of  this  but a r e  Discharge  is  79). T h i s water  I t eventually  1957) and thus may be another  261  Inlet  reaches  significant  in 1  A  300  Fig.  79:  1  S  1  O  N  1  D  J  F  M  A  M  J  J  A  1  S  J  F r a s e r and Cowichan R i v e r d i s c h a r g e from August 1983 t o September 1984 ( d a t a from Environment Canada, 1984; 1985).  262  source of d e t r i t a l The s a l i n i t y , water  column,  materials. oxygen and hydrogen s u l p h i d e p r o f i l e s i n the  measured  a t three s t a t i o n s d u r i n g  the sampling  p e r i o d , are r e p o r t e d i n F i g . 80. From the H S and 0 2  is  readily  apparent that very l i t t l e  2  profiles, i t  water renewal occurred  in  1983. H S was d e t e c t a b l e a t depth throughout the year of sampling 2  until  June  1984. There was no n o t i c a b l e i n c r e a s e  concentration had  H S 2  i n the deep basin during s p r i n g , suggesting that i t  reached s t e a d y - s t a t e .  situated  i n the  The shallowest t r a p s were permanently  i n oxygenated water.  On the other  hand,  the deepest  t r a p s were c o l l e c t i n g m a t e r i a l s i n the anoxic water column, while those  at mid-depth were p o s i t i o n e d near the o x i c / a n o x i c  (Fig.  80). Between June 18^"^ and August 2 4 ^ ,  occurred  i n the water column,  inlet  was renewed.  (Fig.  80). In August,  boundary  dramatic changes  as the deep water of  the  T h i s i s shown c l e a r l y on the 0 /H S p r o f i l e s 2  2  oxygen was present throughout the water  column a t s t a t i o n SI-9 and H S had completely disappeared, 2  at s t a t i o n SN0.8, depth  (between  some t r a c e s of H S were s t i l l 2  100  m  and 160 m),  upwelled anoxic bottom water. H S 2  had  renewal  i s a l s o shown i n F i g . f o r June  profiles  show  18  probably  while  apparent a t midthe remnants  of  S e v e r a l weeks l a t e r , a l l t r a c e s of  disappeared from the e n t i r e  profiles  entire  81,  and August  water  column.  where s a l i n i t y 24  Deep-water and  0 /H S  a r e compared.  These  c l e a r l y the a e r a t i o n of the deepest part  water column by a water mass of higher s a l i n i t y . 263  2  2  of the  There i s a l s o a  Aug.8,'83  N o v . 2 8 , ' 8 3 J a n . 1 2 , ' 8 4 June 18,'84 A u g . 2 4 , ' 8 4  S (%o) 28  0  H S Cumol/I) 0  Pig.  8 0 : 3°/oo over  30 3228  30  40 80 0  40 80 0  and 0 / H S p r o f i l e s 2  t h e time  2  264  30  3228  4 0 80 0  i n t h e water  o f sampling  particulates.  3228  Nov.8,'84  30  32  40 80  column  of the settling  100  B  100  S 150  1 50  Og (ml/l) 20  40  60  80  HgS (umol/l) 200 O  0 (ml/l) 2  •  S  A  H S Cumol/I)  (%o) 2  Aug.24,1984 0  June18,1984  20  40  60  80  H S Cumol/I) 2  Fig.  81:  Comparison  between the S°/oo and 0^  p r o f i l e s measured  i n the water column  on June 18 and August 24, 1984.  265  (%o)  significant presumably bottom August. water  decrease due  to  water.  The  This  could  discharge,  i n oxygen  i t s consumption by H^S  from  mid-depth,  the d i s p l a c e d saline in  be due t o the a r r i v a l of the F r a s e r  whose e f f e c t  River  i s g e n e r a l l y l i m i t e d t o the upper  (Herlinveaux,  1972).  FLUXES OF ORGANIC MATTER The  and  at  upper 30 m were found t o be l e s s  50 m of the water column 4.4.1  concentration  fluxes  of organic  SN0.8 are reported 4.4.1.1 STATION  carbon and n i t r o g e n a t s t a t i o n SI-9  i n Appendix  IV-3.  SI-9  4.4.1.1.1 45 M A  well-defined  seasonal  v a r i a t i o n i n the f l u x  of  organic  carbon can be observed at t h i s depth ( F i g . 82) with a maximum i n 2 J u l y and August (500-600 mgC/m .day), and a minimum i n December 2 and  January  (100-200  mgC/m .day).  There  distinction  i n the nature of the s e t t l i n g  winter,  r e l a t i v e l y high C/N r a t i o  a  proportion material 7.5)  of  terrestrial  organic  i s also organic  a  matter.  (9-10) i n d i c a t e s a matter  compared  c o l l e c t e d i n s p r i n g and summer whose C/N  suggest a predominantly p l a n k t o n i c  origin.  clear In  larger  with  the  r a t i o s (6.5-  The C/N r a t i o of  the m a t e r i a l c o l l e c t e d i n the presence of NaN^ decreases a b r u p t l y during without  February  and March.  preservative,  On the other hand,  i n the t r a p s  the C/N r a t i o of the c o l l e c t e d 266  material  A  S  O  N  D  J  F  M  A  M  J  J  A  S  1 0 9 8  O 5  7  SI-9  800 •  n -  •  «• -  600  (110 •  -»  N a  no  m)  N N a N  E Jr  "  400  -\  200  1 0  9  7  1200  SI-9  1 000  >• ^  x =  O  800  (150  •  •  *•-->•  no  m)  N a N N a N  E CT  O  o  o  CT  600  E 400  200  H A  Fig.  82:  S  O  N  D  J  F  M  A  M  J  J  A  S  Seasonal f l u x e s o f o r g a n i c carbon a t s t a t i o n SI-9 (45 m, 110 m, and 150 m).  267  decreased  earlier  (December and January) and  lower than that of the preserved  was  consistently  m a t e r i a l throughout summer ( F i g .  82) . 4.4.1.1.2 The  110 M flux  of o r g a n i c carbon at 110 m i s  than the f l u x recorded same seasonal  (Fig.  sill.  important d u r i n g the f l u s h i n g  F i g . 8 2 ) . The  82), suggesting  period  C/N r a t i o drops s h a r p l y i n  the presence of r e l a t i v e l y  m a t e r i a l i n the p a r t i c u l a t e s c o l l e c t e d C/N  r e f l e c t s the  of resuspended m a t e r i a l s from the nearby  input i s p a r t i c u l a r l y  (June-August;  larger  a t 45 m ( F i g . 83), although i t shows the  f l u c t u a t i o n s ( F i g . 82). T h i s probably  l a t e r a l advection This  invariably  fresh planktonic  i n s p r i n g and summer.  r a t i o of non-preserved t r a p m a t e r i a l s was always lower  that of preserved  m a t e r i a l s from A p r i l  March  The than  to September.  4.4.1.1.3 150 M The f l u x of organic  carbon at 150 m was intermediate  the f l u x a t 45 m and 110m, part set  inlet  passes over t h i s  and i s t r a n s p o r t e d  f u r t h e r towards the head of the  ( F i g . 83). T h i s s i t u a t i o n  i s , however, r e v e r s e d d u r i n g the  flushing period. from  which seems t o i n d i c a t e that a l a r g e  of the resuspended m a t e r i a l s from the s i l l of t r a p s  between  the  sill  Presumably,  by the h i g h - d e n s i t y  deeper p a r t of the i n l e t , relatively  the m a t e r i a l which was resuspended water  and c o l l e c t e d  i s t r a n s p o r t e d to the  i n the deeper t r a p s . The  low C/N r a t i o observed d u r i n g s p r i n g and summer ( F i g .  268  1 200  SI-9 •  45  1000 o  m  110  m  ° 150  m  i  800 >>  O  O  5  400  200 J A  Fig.  83:  S  O  N  D  J  F  M  A  M  J  J  A S  V a r i a t i o n s i n the o r g a n i c carbon f l u x e s w i t h depth at s t a t i o n SI-9.  269  82)  i n d i c a t e s the presence of r e l a t i v e l y  f r e s h p l a n k t o n i c matter,  presumably o r i g i n a t i n g  from the b i o l o g i c a l  sill  (Parsons et a l . ,  1983). T h i s m a t e r i a l i s mostly  and  trapped  i n the c e n t r a l b a s i n .  observation inlet  made  sediments  systematic  f r o n t present over the resuspended  T h i s i s c o n s i s t e n t with the  on the d i s t r i b u t i o n of o r g a n i c matter (see s e c t i o n  difference  4.4.1).  There  was, however,  between the C/N r a t i o s of  non-preserved t r a p m a t e r i a l s a t t h i s  i n the no  preserved and  depth.  4.4.1.2 STATION SN0.8 4.4.1.2.1 50 M The  carbon  f l u x a t s t a t i o n SN0.8 i s s i g n i f i c a n t l y  than a t s t a t i o n SI-9. zone for  smaller  T h i s i s c o n s i s t e n t with the presence of a  of higher primary p r o d u c t i o n a t the mouth of the i n l e t . s t a t i o n SI-9,  flux  i s also  2 mgC/m .dy; summer  a seasonal f l u c t u a t i o n  observed,  with  a  i n the o r g a n i c  maximum  i n summer  As  carbon (250-300  2 F i g . 84) and a minimum i n winter (~50 mgC/m .dy). The  maximum  i s however reached  earlier  (April)  station  SI-9 ( J u l y ;  sharply  i n February and March from winter v a l u e s of c a .  5.5-6  i n March,  summer  (Fig.  F i g . 82). The C/N r a t i o  and s t a y s r e l a t i v e l y  low  also  than  (6-7.5)  at  decreases 8-9 t o  throughout  84). As observed at s t a t i o n SI-9, t h i s r a t i o  tends  to be lower i n the m a t e r i a l s c o l l e c t e d without p r e s e r v a t i v e . 4.4.1.2.2 130 M and 180 M The  fluxes  at  these  two depths  270  are almost  identical,  0-1 A  0 \ A  , , , • i , . , . . 1 1—— • S  O  N  D  J  F  M  A  M  J  J  A  S  i 1 1 1 1 1 1 1 1 1 1 1—1— S  O  N  D  J  F  M  A  M  J  J  A  S  O  A  Fig.  84:  S  O  N  D  J  F  M  A  M  J  J  A  S  S e a s o n a l f l u x e s o f o r g a n i c carbon a t s t a t i o n SN0.8 (50 m, 130 m, and 180 m).  271  0 I A  Fig.  85:  1 1 1 1 1 1 1 1 1 1 1 1—  i  S  O  N  D  J  F  M  A  M  J  J  A S  V a r i a t i o n s i n the o r g a n i c carbon f l u x e s w i t h depth at s t a t i o n SN0.8.  272  suggesting  a  minimal amount  seasonal v a r i a t i o n s are s t i l l 84).  During  winter,  the  of  resuspension  present but somewhat dampened ( F i g .  carbon  suggesting a c e r t a i n degree  ( F i g . 85). The  fluxes increase  with  of l a t e r a l a d v e c t i o n , while i n summer  a decrease  i n the C f l u x with depth i s observed,  that  main source of organic carbon at t h i s s t a t i o n  the  euphotic these  zone.  depths  Moreover, were  The are  depth,  thus  indicating i s the  seasonal v a r i a t i o n s i n C/N r a t i o s found very  s i m i l a r to  those  observed  at  50  the C/N r a t i o s of the m a t e r i a l s recovered without  always  lower than those recovered i n the presence  at m. NaN,  of  the  p r e s e r v a t i ve. 4.4.1.3 DISCUSSION The  organic  deployed  in  importance Marine  materials  c o l l e c t e d from the  Saanich I n l e t have s e v e r a l o r i g i n s  sediment whose  traps  relative  v a r i e s i n time and space. sources are predominant  i n s p r i n g and  summer.  They  consist  mainly of s i n k i n g p l a n k t o n i c c e l l s d u r i n g the e a r l y  of  spring  the  throughout  bloom,  summer.  and f e c a l p e l l e t s i n  Unlike  planktonic  o r i g i n a t e from the euphotic zone, at  any  migration organic  depth  (e.g. Barry,  is directly  which  can  of the d i e l  1967).  dependent on the  f i x a t i o n by p h o t o s y n t h e t i c organisms  273  spring  f e c a l m a t e r i a l can be  i n the water column because  of zooplankton matter  cells,  late  and only  egested vertical  This  source  rate  of  i n the euphotic  part  zone,  of  carbon thus  Table  38:  Annual  carbon  and  aluminium  fluxes  and  accumulation rates i n sediment at s t a t i o n  Depth  C  „ Flux org  (gC/m  2  ( 2 )  yr)  45 m  122 ( 1 1 2 )  110 m 150 m Sediment  C/N  A l Flux  C/Al  (gAl/m y r ) 2  8.0+0.5  102 (102)  1.20 (1.10)  181 (164)  8.2+0.5  240 (230)  0.75 (0.71)  179 (140)  8.3+0.5  289 (214)  0.62 (0.65)  9.8+0.5  169  0.46  77  ( 3 )  (1) Preserved t r a p m a t e r i a l s . (2) Weighted average over the year of sampling. (3) Numbers  i n b r a c k e t s i n d i c a t e average f l u x e s and r a t i o s  obtained o m i t t i n g the two months of f l u s h i n g August,  1984).  274  (July  and  explaining euphotic  the zone  higher  flux  at SI-9  of carbon 2  (122 gC/m  .yr;  found  just  Table 38)  below  the  compared  with  SN0.8 (57 gC/m .yr; Table 40). 2  The  t e r r e s t r i a l component of the o r g a n i c matter  sediments  found i n the  of Saanich I n l e t o r i g i n a t e s mainly from water  run-off,  and t h e r e f o r e i t s input f o l l o w s the r i v e r d i s c h a r g e p a t t e r n .  The  Cowichan R i v e r i s the main source of t e r r e s t r i a l d e b r i s and has a maximum  discharge i n f a l l  (Fig.  79).  The  r e l a t i v e p r o x i m i t y of  SI-9 t o Cowichan Bay e x p l a i n s the higher f l u x of carbon at this station d u r i n g the winter months (C flux from 12/1/84 to org 3  5/3/84: SI-9, Lateral  n  160 mgC/m .dy; SN0.8, 53 mgC/m .dy). 2  transport  2  of resuspended  sediments from  environments i s a l s o a very important c o n s i d e r a t i o n , for  station  inlet  (Fig.  SI-9,  due to i t s p r o x i m i t y with the  27).  I t has been argued that the s i l l  of  r e l a t i v e l y strong t i d a l c u r r e n t s  effect  of  this  evident  i n the deepest t r a p s (110 m and  thus  explaining  depth  resuspension  i s expected  the s i g n i f i c a n t  observed at t h i s s t a t i o n  increase  of  the  sediment  by the  ( s e c t i o n 4.3). to  be  The  particularly SI-9,  i n c r e a s e i n carbon f l u x e s  (Fig.  83).  i s not observed at s t a t i o n  This increase  with could  However, s i n c e  SN0.8,  is  sorting  150 m) deployed at  a l s o be p a r t l y due to zooplankton m i g r a t i o n . an  particularly sill  mainly composed of a l a g d e p o s i t which i s produced effect  shallower  this  such  mechanism  cannot be very important. The  comparatively  lower carbon accumulation 275  rate  in  the  sediment  at s t a t i o n SI-9  compared to the C f l u x at 150 m  38)  can be due  the  sediment-water i n t e r f a c e and  deposited in  the  to b i o l o g i c a l m i n e r a l i z a t i o n of organic matter at  sediment  s t a t i o n SI-9  larger  than  suggesting though  to resuspension  of  the  newly-  sediment. A comparison.between the A l accumulation and  the s e t t l i n g  d i s t i n c t i o n between these two at  (Table  There i s ,  at 150  processes.  Table  the annual A l f l u x recorded  the  A l accumulation  that resuspension  this  flux  sediment  however,  rate  occurs  in  at  m 38  allows  in a  some  i n d i c a t e s that  150 m i s 1.7  the  times  sediment,  to a s i g n i f i c a n t  i s deposited  rate  thus  extent,  even  stagnant  environment.  an a l t e r n a t i v e and more l i k e l y  explanation.  210 Sedimentation r a t e s , as measured by an  average  over s e v e r a l decades,  here estimate 1983 a  and  Pb  i n sediments,  represent  while  the t r a p data  reported  the f l u x of m a t e r i a l which o c c u r r e d  September  1984.  Therefore,  between  August  interannual v a r i a t i o n s  bring  l a r g e degree of u n c e r t a i n t y to the c o n c l u s i o n s drawn from  comparison of these the was  two  s e t s of data.  year of sampling was  fairly  the  There are i n d i c a t i o n s that  atypical,  in that the  flushing  e x c e p t i o n a l l y i n t e n s i v e . T h i s f l u s h i n g i s r e s p o n s i b l e f o r the  large SI-9  i n c r e a s e i n f l u x recorded  d u r i n g the months of J u l y and August.  discrepancy accumulation during  i n the deepest t r a p s at  between the A l (and C) r a t e may  the year  f l u x at 150  be i n p a r t due  of sampling.  m and  the the  apparent sediment  to an abnormally high  I f the two 276  Thus,  station  months of f l u s h i n g  flux are  not  taken  i n t o account  (Table 38;  i n the c a l c u l a t i o n of the y e a r l y  average  i n b r a c k e t s ) , the agreement i s much c l o s e r , as the A l  flux  becomes only 1.27 times l a r g e r than the accumulation  Some  resuspension  explain mainly  a t SI-9 would however be s t i l l  the data.  It  i s likely  that such  rate.  necessary  resuspension  to  would  occur during the f l u s h i n g p e r i o d s .  Notwithstanding  such u n c e r t a i n t i e s ,  i tis still  p o s s i b l e to  estimate  roughly the extent of b i o l o g i c a l m i n e r a l i z a t i o n at the  sediment  interface  by c a l c u l a t i n g the C/Al r a t i o s  p a r t i c u l a t e s and sediment. T h i s r a t i o drops 0.46  of  settling  from 0.62 a t 150 m to  a t the sediment s u r f a c e (top two cm; Table 38). I f we assume  that A l and C behave i n a s i m i l a r way during resuspension, i t can be argued at  the  that c a . 25% of the organic matter interface.  However,  hydrodynamic behaviour  particles  estimate  the assumption  above  the  aluminosilicates.  must t h e r e f o r e be taken as  v a l u e . The s i g n i f i c a n t decrease in  about  the  as one  resuspension of low-density o r g a n i c -  compared to h e a v i e r  computed  made  of A l and C i s probably erroneous,  would expect a p r e f e r e n t i a l rich  has been m i n e r a l i z e d  The 25% a  i n C/Al r a t i o with depth  t r a p m a t e r i a l s (Table 38) c h i e f l y  reflects  the  maximum observed lateral  a d v e c t i o n of m a t e r i a l s with i n c r e a s i n g l y lower C/Al r a t i o s due to differential  s e t t l i n g between a l u m i n o s i l i c a t e s and  particulates  rather  than  organic  carbon  organic-rich  mineralization.  The  c o n t i n u a t i o n of such a t r e n d towards the sediment i n t e r f a c e would also  lead  to  an  overestimate 277  of  the  extent  of  biological  mineralization,  thus c o n f i r m i n g that the above estimate must  taken as a maximum v a l u e . materials that  and  most  sediment  A comparison of the C/N  (Table 38)  of the carbon  suggests,  be  r a t i o s of t r a p  on the other  m i n e r a l i z a t i o n occurs at  the  hand,  sediment  interface. Resuspension expected  to  remoteness winter, 50  m  and  occur from  85),  station  to a l e s s e r extent because of  the  the carbon (Fig.  l a t e r a l a d v e c t i o n at  sill  or any  extensive  f l u x e s at 130 m and  carbon  the  main  180 m are l a r g e r than  at  transport i s reversed,  summer,  zone.  Some  however,  9,  where  important  lateral  is  always  than the f l u x from the euphotic  by  i s completely  f l u x . T h i s i s in c o n t r a s t with s t a t i o n advection  and  lateral  as shown  the A l f l u x e s (Table 39), but the a s s o c i a t e d carbon masked by the v e r t i c a l  from  T h i s c o u l d i n d i c a t e that  i s the euphotic  continues through  relative In  f l u x d i m i n i s h e s with depth.  transport s t i l l  are  area.  thus suggesting some l a t e r a l  source of carbon  its  shallow  shallower environments. In summer, the s i t u a t i o n the  SN0.8  quantitatively  SImore  zone.  Since there i s some l a t e r a l t r a n s p o r t at s t a t i o n SN0.8, the difference indicates between  in the  carbon minimum  of  carbon  mineralized  these two depths ( i . e . at l e a s t  l e s s organic carbon part  f l u x between 50 m and  the  water  130  m  (Table  during  15-20%).  transport  Significantly  seems to have been m i n e r a l i z e d i n the column which was  278  anoxic  at  39)  the  deepest time  of  Table  39:  Seasonal  C  and  Al  f l u x e s at s t a t i o n SN0.8.  Fluxes Depth  Jan.-Feb. C  Al  (mg/m  .dy)  Apr.-Aug C  Al  50 m  53  270  28  130 m  105  227  59  180 m  92  218  60  279  sampling. and  The  r e l a t i v e consistency  of the A l f l u x between 130 m  180 m (Table 39) suggests that there  advection  d i f f e r e n c e between C accumulation r a t e s in sediment and the  flux  (Table  or resuspension  40)  should  from the  therefore r e f l e c t  m i n e r a l i z a t i o n at the sediment s u r f a c e . data  suggest  that c a .  deep  lateral The  180m  depth  little  basin.  at  at  i s very  the  extent  of  As f o r s t a t i o n SI-9, the  20% of the s e t t l i n g  organic  matter  is  m i n e r a l i z e d a t the sediment-water i n t e r f a c e . During  s p r i n g and summer,  the C/N r a t i o s were c o n s i s t e n t l y  lower  i n the non-preserved t r a p m a t e r i a l s , except at SI-9, 150 m  (Fig.  82). S t a t i s t i c a l  shallowest  treatment of the data obtained  t r a p s at both s t a t i o n ,  (Kruskal-Wallis  test,  Sokal  from  using a non-parametric method  and Rohlf,  1981) suggest that  d i f f e r e n c e s observed are s i g n i f i c a n t at the 95% confidence (a  similar  between  test  the  observation  indicates  1970;  in  of  Wassman,  1983),  materials  was  egested detritus  any  that  significant  N-containing  compounds  as  level  differences  biocide).  having  the  This  a preferential has  particulates  often  been  (e.g. Degens,  1979; Honjo et a l . , 1982; Gardner et a l . , 1983; the  bacterial  associated  has a l r e a d y  fecal  without  i n s t e a d of  sediments and s e t t l i n g  Rosenfeld,  phenomenon  reveal  C f l u x e s measured with or  mineralization noticed  d i d not  the  with  colonization nitrogen  been observed,  p e l l e t s from d e p o s i t  of  these  enrichment.  Such  a  p a r t i c u l a r l y with f r e s h l y  feeders  (Newel,  1965) and  d e r i v e d from e s t u a r i n e macrophytes ( H a r r i s o n and 280  trap  Mann,  Table  40:  Annual  accumulation  carbon  rates  in  fluxes  and  sediment  at  s t a t i o n SN0.8 * (1  Depth  50  C  „ Flux 9 . (gC/m.y)  C/N  ( 2 )  o r  57  7.4+0.5  130 m  57  7.9+0.5  180 m  55  7.8+0.5  Sediment  43  8.9+0.5  (1) Preserved t r a p m a t e r i a l s . (2) Weighted average sampling.  281  over the year of  1975;  Rice  and  enrichment transfer  is  due  (Rice,  detritus  has  also  1982). - T h i s r e l a t i v e accumulation of N  incorporation  into  collected  in  resuspension is  population  humified  the  observed deepest  from the s i l l  in traps  nitrogen.  fresh  colonization  (Newel,  materials the at  1965)  (Rice,  1982).  non-preserved station  by  N-  This  N-  materials  SI-9,  where  only  enriched  (1984) a l s o reported a higher  C/N  r e l a t i v e to those recovered Hg  the  possibility  + +  without b i o c i d e .  d i d not produce such an e f f e c t ,  However,  NaN^  formaline  thus c a s t i n g doubt  of a b a c t e r i a l mediation f o r the  in  ratio  i n m a t e r i a l s c o l l e c t e d by sediment t r a p s i n the presence of  and  a  to  made by Newel(l965) that  organic m a t e r i a l becomes q u i c k l y  Knauer et a l .  or  in  i s the dominant source of carbon. T h i s  c o n s i s t e n t with the o b s e r v a t i o n  relatively  carbon,  N-  from seawater to the d e t r i t a l pool has  been a t t r i b u t e d to t h e i r  not  the  net  microbial  was  Although in some cases  a  protein-rich  enrichment  1981).  to a p r e f e r e n t i a l r e l e a s e of  of n i t r o g e n  been observed the  Tenore,  on  N-enrichment  observed. 4.4.2  FLUXES OF MAJOR ELEMENTS The  f l u x e s of major elements at s t a t i o n s SI-9  reported  i n Appendix IV-3.  input of t e r r i g e n o u s linked Fraser  to  SN0.8 are  These f l u x e s w i l l mainly r e f l e c t  m a t e r i a l s , and  r i v e r discharge,  and  t h e r e f o r e are expected to be  principally  River. 282  the  from the  Cowichan  and  S I - 9  •  (45  • N a N no  m)  3  N a N „  T3  e  11  >•  T3 J  CT  0  0 3  •  0  02  •  0  0  1 •  0.4  0.3  i  0.2  0.3 0.2 0.  0  08  •  0  0 6  •  0  0 4  •  0  02  •  0  10  •  0  0 8  •  0  06  •  0  0 4  -  >* •o eg  1  E  ^-  cn  >> •o CM E cn  >•  o  0 . 1 5  J  N E  CT  0.10 0.05  A  Fig.  86:  S  O  N  D  J  F  M  A  M  J  J  A  S  Seasonal f l u x e s of major elements 45 m).  283  (SI-9  r  4.4.2.1 STATION SI-9 4.4.2.1.1 45 M The  f l u x e s of A l ,  Fe,  Mg, T i , Ca, and K at t h i s depth show  very s i m i l a r seasonal v a r i a t i o n s for  (Fig.  a l l these elements i n November  86). A peak was recorded 1983,  corresponding  maximum water d i s c h a r g e from the Cowichan R i v e r reaching a minimum i n March, a  a gradual increase  maximum was reached i n summer.  increasing which also  abundance  This  increase  suggested of  was observed and may r e f l e c t  of s i n k i n g organic aggregates  the  Honjo (1982) t o  biogenic  Panama Basin. reflect  by  the  and l i t h o g e n i c p a r t i c l e  a r r i v a l of the c l a y - r i c h Fraser  This  was  seasonal  co-  fluxes  of the water column during  t h i s period  River  i n the  of o p a l i n e  could  plume as  was  observed i n the upper 30  m  of time ( F i g . 81).  d i s p l a y s a s l i g h t l y d i f f e r e n t seasonal p a t t e r n  relatively  the  ( F i g . 83)  The maximum f l u x observed i n J u l y and August  suggested by the lower s a l i n i t y  Si  explain  a  79). A f t e r  scavenge suspended c l a y s from the water column.  variation  also  (Fig.  to  with  a  enhanced f l u x i n s p r i n g and summer due t o the s i n k i n g silica  ( F i g . 86). T h i s  i s shown more c l e a r l y i n F i g .  87  where the seasonal v a r i a t i o n s of the S i / A l r a t i o are reported  and  i n F i g . 88  the  where o p a l - S i  aluminosilicate  has been estimated by  contribution  aluminosilicate contribution  from  the  total  substracting Si  was estimated by m u l t i p l y i n g  (the  the A l  f l u x by the S i / A l r a t i o of the winter samples ( F i g . 8 6 ) ) . Other  elemental r a t i o s show some seasonal v a r i a t i o n i n the 284  Fig.  87:  Seasonal v a r i a t i o n s i n the S i / A l r a t i o s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9.  285  of  the  SI-9  A  S  O  N  D  J  (45  F  m)  M  A  M  J  J  A S  F i g . 88: Seasonal f l u x e s of o p a l i n e s i l i c a a t s t a t i o n SI-9.  286  SI-9  J  Fig.  A  S  O  N  (45  m)  —  + NaN  +--+  no  D  J  F  3  NaN  M  A  M  J  J  A S  89: Seasonal v a r i a t i o n s i n the K/Al and F e / A l r a t i o s of s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9 (45 m).  287  chemical composition  of the l i t h o g e n o u s m a t e r i a l s introduced  the i n l e t . The c o n t r a s t i n g behaviour 89,  where  In  the case of F e / A l ,  very c l o s e to d e t e c t i o n l i m i t , t r e n d from October  1983  gradual  the seasonal  to March 1984.  On  displays  i n November 1983,  a particularly striking  downward  the other hand, a  i n c r e a s e toward maximum values i n  are  f l u c t u a t i o n s are  but there seems to be a  drop i n the K/Al r a t i o i s recorded  ratio  of Fe and K i s shown i n F i g .  the seasonal v a r i a t i o n s i n Fe/Al and K/Al r a t i o s  indicated.  a  into  f o l l o w e d by  summer.  pattern  sharp  The  (Fig.  Fe/K  90).  A  prominent maximum i s a s s o c i a t e d with the maximum i n water run-off (Nov.  1983).  Subsequently,  winter,  drops  summer.  Similarly,  could  be  illite  s h a r p l y i n March and  detected  summer sample d i s p l a y e d  o (9.8 A) which was  November sample ( F i g . was  A  throughout  stays r e l a t i v e l y low  v a r i a t i o n s i n the mineralogy  detected.  peak  i t stays r e l a t i v e l y high  almost  completely  of the a  through samples  well-defined  absent  in  the o  91). On the other hand, hornblende (8.4  i n the f a l l  sample but not  i n the  summer  A)  sample.  Such chemical and m i n e r a l o g i c a l v a r i a t i o n s c o u l d r e f l e c t a change i n the source of the l i t h o g e n o u s m a t e r i a l . time of higher water r u n - o f f , at  station  SI-9  most of the l i t h o g e n o u s  come from the Cowichan  c o n s i s t s i n l a r g e p a r t of v o l c a n i c rocks a predominant mafic c h a r a c t e r . diminishes, suspended  In winter, during the  catchment  materials area  which  (see s e c t i o n 4.2.3) with  As the i n t e n s i t y of p r e c i p i t a t i o n  the importance of t h i s source, compared with that of c l a y m i n e r a l s c a r r i e d by water-masses from more remote 288  SI-9  0 l . i i i i i A S O N D J  (45  i  i  i  i  i  i  F  M  A  M  J  J  i A  m)  i S  Seasonal variations i n the Fe/K ratio of s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9 (45 m).  289  o<  290  areas  (such as the F r a s e r e s t u a r y ) ,  source  a l s o decreases.  of l i t h o g e n o u s m a t e r i a l s seems t o c o n t a i n a s i g n i f i c a n t l y  higher p r o p o r t i o n of 4.4.2.1.2  illite.  110 M and 150 M  U n l i k e at 45 m,  the major element f l u x e s at 110 m  s t a t i o n do not show any c o n s i s t e n t seasonal is  likely  that p e r i o d s of high  high t u r b u l e n c e and  T h i s second  on the s i l l  f l u x e s correspond  d u r i n g the month of f l u s h i n g . f l u x e s obtained  this  ( F i g . 92). I t to periods  which would produce more  l a t e r a l a d v e c t i o n . T h i s resuspension  larger  pattern  at  of  resuspension  was p a r t i c u l a r l y  intense  T h i s i s c l e a r l y shown by the  at 150 m during J u l y and August  much  (Fig.  93  and 94). Such  a  flux pattern  i s i n c o n t r a s t with that observed  organic carbon which showed a seasonal p a t t e r n  (particularly  for at  110  m) with an i n c r e a s i n g trend through s p r i n g ,  superimposed on  the  "saw-teeth"  elements ( F i g .  82). on  T h i s suggests that the organic m a t e r i a l which i s the  sill  deep b a s i n . will  p a t t e r n observed f o r the major  be  i s very  r a p i d l y resuspended and t r a n s p o r t e d t o  In s p r i n g ,  preferentially  sediment/water  low-density,  organic-rich  i n t e r f a c e by t i d a l c u r r e n t s ,  95).  During  flushing,  c u r r e n t has resuspended a much higher also reflected  i n a lowering  during  a particularly  load of sediment.  of the C g / A l r a t i o Q r  291  at  the  thus e x p l a i n i n g the  o r  summer ( F i g .  the  particulates  t r a n s p o r t e d upon t h e i r a r r i v a l  i n c r e a s i n g C g / A l r a t i o of the m a t e r i a l c o l l e c t e d and  deposited  ,  spring strong  T h i s was  particularly  SI-9 .  (110  m)  • +NaN  g  • no NaNg  A  Fig.  92:  S  O  N  D  J  F  M  A  M  J  J  A  S  Seasonal f l u x e s of major elements 110 m).  292  (SI-9,  A  S  O  N  D  J  F  M A  M  J  J  A S  F i g . 93: Seasonal f l u x e s of A l at s t a t i o n SI-9 (150 m).  293  2.4 SI-9 2.0 4 +  —  45  m  110m  +  »....4>  150  m  T3 CM  E  •—  1.2 J  0.8 4  0.4 4  0  i A S  i  i O  i N  i  i  .  .  D  J  F  M  .  . A  . M  . J  • J  A  F i g . 94: V a r i a t i o n s i n the A l f l u x w i t h depth a t s t a t i o n  294  S  SI-9.  SI-9 110  m  »....© 1 5 0  m  +  1.0  _-  +  0.8  N  0.6 -  0.4  i:  A  S  Seasonal  O  N  D  J  variations  F  M  A  M  i n the C  J  J  A S  / A l r a t i o of  the  p a r t i c u l a t e s a t s t a t i o n SI-9 (110 m  and  org settling 150  m).  295  SI-9 +--+  110  m  o 150  m  4.0 4 2CT  e  3.6 4 CD  4 :  3.2 4  2.8  i J  Fig.  96:  i A  i  1  S  Seasonal settling 150 m).  O  N  1  D  1  J  i  i  1  F  M  A  i M  i J  i  i J  i A S  variations i n the Fe/K ratio of p a r t i c u l a t e s a t s t a t i o n SI-9 (110 m  296  the and  in  the 150 m t r a p ( F i g . 95). There  ratios of  (Fig.  no systematic  seasonal  variations in  96), which i s t o be expected i f a l a r g e  the Fe/K proportion  t h i s m a t e r i a l c o n s i s t s of resuspended sediment from the s i l l .  The at  were  Fe/K annual average of the sediment-trap m a t e r i a l s c o l l e c t e d 110  which  m and 150 m was 3.52+0.06 is  central found  s i m i l a r to the average value  basin  (3.4+0.2;  i n the eastern  annual  and  3.55+0.06  of the sediments  F i g . 43) but d i f f e r e n t  sill  sediments  respectively,  (2.6+0.1).  of the  from the  ratio  S i m i l a r l y , the  average of the Fe/Al r a t i o s of the t r a p m a t e r i a l s  (0.69+  0.01 and 0.68+0.01 f o r the 110 m and 150 m t r a p s r e s p e c t i v e l y ) i s s i m i l a r to that reported and  41), but u n l i k e that from the e a s t e r n  much of  (0.67+0.04;  sill  F i g . 40  (0.48+0.02). Since  of the m a t e r i a l s c o l l e c t e d i n these t r a p s must be a resuspension  increase  with  sorting and  f o r the deep basin  from depth),  of the s i l l  the s i l l  of  these r a t i o s are compatible  sediment,  F e - r i c h clay minerals,  enriched  ( s i n c e the f l u x e s  preferential  and the formation  i n f e l d s p a r s (and q u a r t z ;  result  materials  with  tidal  resuspension of a  see s e c t i o n 4.3,  lag  of  K-  deposit  4.4.1,  and  4.4.3) . 4.4.2.2 STATION SN0.8 Only enough discuss  the samples c o l l e c t e d from A p r i l to August were  f o r a n a l y s i s by XRF. the  seasonal  It i s therefore  not  f l u c t u a t i o n s i n the f l u x e s of  minor) elements at t h i s s t a t i o n . 297  large  possible major  to  (and  One can note however that the f l u x e s of major elements which were measured at s t a t i o n SN0.8 (50 m) a r e , on average, of  magnitude  lower  than  at  station  SI-9  one order  (Appendix  IV-3).  Moreover, the S i / A l and C / A l r a t i o s of the m a t e r i a l s c o l l e c t e d org at  SN0.8 a r e much l a r g e r than a t SI-9 (Table 41). T h i s confirms  that,  although the carbon  inlet, opal  the  u n d e r l y i n g sediment has a higher organic carbon  content  materials There  f l u x decreases towards the head of the  because  (see s e c t i o n are  fluxes  of  Higher  fluxes  months  of  of  a  lesser  dilution  i n the magnitude  elements a t 50 m over the 5  of aluminium and i r o n were  A p r i l and May (Appendix  obtained  Silicon  analyzed. during  79), compared with  s p r i n g and summer when these f l u x e s decreased of two.  months  of the  the  IV-3) probably because of  higher r u n - o f f during t h i s p e r i o d ( F i g .  factor  lithogenous  4.4.1).  significant variations  major  by  and  a late  by approximately  shows a s i m i l a r p a t t e r n ,  although  element i s not only c o n t r o l l e d by a l u m i n o s i l i c a t e s ,  a  this  but a l s o by  biogenic opal. The A l f l u x i n c r e a s e s s i g n i f i c a n t l y between 50 m and 130 indicating  some l a t e r a l t r a n s p o r t at mid-depth  m,  ( F i g . 97). The  f l u x e s measured at 130 m and 180 m are, however, almost  identical  over the p e r i o d of a n a l y s i s ,  amount of  thus  i n d i c a t i n g a minimal  l a t e r a l a d v e c t i o n and b e n t h i c resuspension at t h i s s t a t i o n deepest  i n the  p a r t of the b a s i n , even d u r i n g the month of f l u s h i n g .  298  Table  41:  materials  Average C  / A l and S i / A l r a t i o s i n sediment  c o l l e c t e d at s t a t i o n SI-9 and SN0.8 from May  trap 5  to  August 24, 1984.  SI-9 Depth  C  org/  A l  SN0.8 Si/Al  Depth  45 m  1 .6  7.2  50 m  110m  0.9  5.2  150 m  0.6  Sediment  0.46  C  org/  A l  Si/Al  10.3  21.3  130 m  3.8  11.8  5.0  180 m  3.7  11.4  4.3  Sediment  1 .0  299  6.0  SN0.8 (50  (130  0.08  • 0.04  0  97:  m) m)  • ( 1 8 0 m)  A  A  S O ' N D J  Variations SN0.8.  F  M  A  M  J  J  A S  i n the A l f l u x e s with depth a t s t a t i o n  300  4.4.3  FLUXES OF MINOR ELEMENTS The  f l u x e s of minor elements at s t a t i o n SI-9 and SN0.8  are  r e p o r t e d i n Appendix IV-3. 4.4.3.1 BARIUM From deduced  the sediment a n a l y s i s that  Ba  distribution  c o n t r o l l e d by two phases. i s present appears  ( s e c t i o n 4.4.6.1), i n Saanich I n l e t  a l s o to be present  i n a b i o g e n i c phase,  with  an estimate of the opal content  52).  The  correlates water  column  (i.e.  ratios correlate Si/Al  ratios;  i n the open ocean.  1977).  zones (Goldberg and A r r h e n i u s , Schmitz,  1987)  well Fig.  Dissolved  with d i s s o l v e d s i l i c a and a l k a l i n i t y  (Chan et a l . ,  and  it  p a r t i c u l a r l y in  in  Barium a l s o o f t e n occurs  higher c o n c e n t r a t i o n i n sediments u n d e r l y i n g higher  1980;  K,  of barium i n biogeochemical processes  particularly  closely  essentially  where i t p r o x i e s f o r  the c e n t r a l basin sediments where the Ba/K  well established,  is  been  While a l a r g e p r o p o r t i o n of the barium  i n the a l u m i n o s i l i c a t e s ,  involvement  i t has  is Ba the in  productivity  1958; Brongersma-Sanders, et a l . ,  i t has been argued that  it  can  be  t r a n s p o r t e d t o the sediments as b a r i t e c r y s t a l s or i n a s s o c i a t i o n with  skeletal materials  relevance Ba  1980).  to the present study i s the c o r r e l a t i o n  Of  particular  found  between  c o n c e n t r a t i o n and o p a l content i n the sediments of the Bering  Sea (Goldberg, find  (Dehairs et a l . ,  any  1958).  barium  However, C a l v e r t and P r i c e  enrichment i n the  301  diatomaceous  (1983) d i d not ooze  on  the  Namibian  Shelf.  Instead,  they  found higher  Ba c o n c e n t r a t i o n i n  the upper reaches of the c o n t i n e n t a l slope which they to  a  lower  influence  sediment accumulation  of  and  possibly  m i c r o f l a g e l l a t e algae which a r e known  barite crystals The  rate,  good c o r r e l a t i o n obtained  confirms  to the  to  between the c o n c e n t r a t i o n s of  the  (r=0.92; F i g .  importance of the a l u m i n o s i l i c a t e s .  There was  no apparent i n c r e a s e i n the Ba/K r a t i o s d u r i n g the summer (Fig.  99), even  observed were  (Fig.  at  45 m where a w e l l - d e f i n e d opal  87). The Ba/K values obtained  months  peak  was  at the three depths  i n d i s t i n g u i s h a b l e and a l l were w i t h i n the 2O" values of the  analytical error. Ba  secrete  ( F r e s n e l et a l . , 1979).  Ba and K ( c o r r e c t e d f o r s e a - s a l t ) at s t a t i o n SI-9 98)  attributed  T h i s suggests t h a t ,  at t h i s s t a t i o n ,  biogenic  does not have any n o t i c a b l e i n f l u e n c e on the Ba c o n c e n t r a t i o n  of the s e t t l i n g p a r t i c u l a t e s . This  is  in  sharp  c o n t r a s t with the behaviour  of  Ba a t  s t a t i o n SN0.8. In t h i s case, a w e l l - d e f i n e d Ba/K peak occurred i n May-June ( F i g . Si/Al  100), when a s i m i l a r maximum was observed i n the  ratio. Such c o n t r a s t i n g behaviour between the two s t a t i o n s c o u l d be  due  to  the  much  higher  proportion  of  opal  found  i n the  p a r t i c u l a t e s s e t t l i n g at SN0.8.  The S i / A l r a t i o corresponding to  the Ba/K peak was c a .  100). T h i s r a t i o never exceeds 8  34 ( F i g .  at SI-9 ( F i g . 87) r e f l e c t i n g the much l a r g e r input of lithogenous m a t e r i a l s at t h i s s t a t i o n .  The b i o g e n i c Ba s e t t l i n g a t SN0.8 can 302  Table 42: Fluxes of b i o g e n i c barium at s t a t i o n  Time of deployment  5/3- 9/4  K fl (g/m .dy) u  x  295+30 301+30  24 + 65 38 + 64  (NaCl) 0. 0108 — (NaN )  395+51  499+50 394+40  96+101 -  (NaCl) 0. 0057 (NaN ) 0. 0060  209+27 220+29  351+36 423+42  142+63 203+71  (NaCl) (NaN ) 0. 0044  161+21  212+21 227+23  _  66 + 44  (NaCl) 0. 0068 (NaN,) 0. 0064  249+32 234+30  267+27 274+27  18 + 59 40 + 57  3  1.8/6-16/7  3  16/7 -24/8  * Error  Biogenic Ba f l u x (jug/m .dy)  271+35* 263+34 —  3  10/5 -18/6  Total Ba f l u x (ug/m .dy)  (NaCl) 0. 0074 (NaN ) 0. 0072 3  9/4- 10/5  Lithogenic Ba f l u x (ug/m .dy)  SN0.8 (50 m).  bars estimated from a n a l y t i c a l p r e c i s i o n  303  (2<T).  Fig.  98:  Correlation between K particulates collected three depths).  304  and Ba i n the at s t a t i o n SI-9  settling (at the  .  •  A  Fig.  99:  S  O  N  D  J  45  m  110  m  o 150  m  F  M  A  M  J  J  Seasonal v a r i a t i o n s i n the Ba/K ratio s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9.  305  A S  of  the  S N 0 . 8 (50 SN0.8 (180  0 •  i A  S  i  i  i  O  N  D  i J  i  m)  i F  . + NaN^  m)  M  + no  i  i  i  A  M  J  NaN  .  i  J  •  A S  . 100: Seasonal v a r i a t i o n s i n the Ba/K and S i / A l r a t i o s of the s e t t l i n g p a r t i c u l a t e s a t s t a t i o n SN0.8.  306  SN0.8 (50 m) 200 100 3.  0• A  101:  S  O  N  D  J  F  M  A  '  M  '  J  J  A  S  Seasonal f l u x e s of b i o g e n i c barium a t s t a t i o n SN0.8 (50 m).  307  be  estimated  t o t a l Ba  flux  estimated the  by  subtracting  (Table 42;  from the  lithic  settling  Fig.  particulates  an  estimate of the  average Ba/K  collected  at  stations  i s i d e n t i c a l , which i s supported by  existing  between the A  associated  r a t i o of the  SI-9).  that  52).  S i / A l and  - 150  values,  ppm is-  0.67  the  g/m  .dy  was°  ratio  of the  calculation  phase good  at  both  correlation  large  of o p a l i n e  uncertainties  IV-3). i . e . the  Ba/K  l i m i t of As  With an  section  estimate  these  obtained  4.4.6.1). A  to 3000 ;ug Ba/m  .dy,  f l u x would represent only  analytical precision  r a t i o of ca.  12%  i n the  (Appendix 10 - 20%  of  measurement  (2<T), such a s i g n a l would be at  the  detection. discussed  explanation is  ppm;  from 1500  b i o g e n i c Ba  total flux.  of the  which  the  varied  250  on  of  similar 2 a s s o c i a t i o n at the peak of opal f l u x at SI-9 (ca. 1.1 g Si/m .dy) 2 would produce an a d d i t i o n a l Ba f l u x of ca. 285 ;ug Ba/m .dy. The total Ba f l u x at t h i s s t a t i o n , at t h i s time of the year (June 2 through August),  (ca.  silica.  in opal s k e l e t o n s  reasonable agreement with the  from sediment a n a l y s i s  Ba/K  This  lithogenous  concentration  which, c o n s i d e r i n g the in  the  Ba/K  a f l u x of ca.  T h i s would correspond to a Ba 100  from  r a t i o s in the i n l e t sediments 2 150-200 ;ug/m .dy of b i o g e n i c Ba was 2  f l u x of c a .  with  flux  value o b t a i n e d from  assumes  (Fig.  Ba/K  l i t h o g e n o u s Ba  101).The l i t h o g e n o u s f r a c t i o n  K f l u x and  phase ( i . e . the  the  the  for also  in section the  Ba  4.4.6.1,  distribution  consistent  with the 308  there i s an  i n Saanich I n l e t data  collected  alternative sediments from  the  sediment SN0.8  trap  (and  sediments)  moorings.  sill.  could  to  at  zone  However,  stratified,  be  due  SI-9  because of  at  station  producing  At t h i s stage, possibilities.  The  f o r b a r i t e input  SN0.8  the  resolved.  water  of  the  column  the  nearby is  more during  micro-algae. to d i s t i n g u i s h between and  would seem to  Si/Al  However,  with  these i n the  weaken  s i n c e m i c r o f l a g e l l a t e s cannot  the  thrive  sampling i n t e r v a l s  A more d e t a i l e d sampling program,  taxonomic determination  i s needed  of  in  the  in  to c l a r i f y  association the nature  central  basin  lead,  sediments  however, to a Ba because  the  of t h i s b i o g e n i c component i s s i m i l a r to or  than that found in the a l u m i n o s i l i c a t e s . observation  of  barium.  a d d i t i o n of b i o g e n i c Ba does not  concentration  the  compete  s p e c i e s s u c c e s s i o n w i t h i n s h o r t e r time p e r i o d s cannot  the c a r r i e r of b i o g e n i c  with  from  1987), which would be conducive to  peak at SN0.8  when diatoms are blooming.  enrichment  barite  replenishment  c o r r e l a t i o n between Ba/K  argument  The  the  i t is difficult  particulates  with  of  fjord  a nutrient-depleted surface layer  settling  be  addition  station  inner  with n u t r i e n t s by t i d a l mixing above  the p r o l i f e r a t i o n of such  + 1 month,  the  at  These algae would not be able to  summer (Sancetta and C a l v e r t ,  two  observed  values observed i n the  diatoms  euphotic  peak in Ba/K  the higher Ba/K  m i c r o f l a g e l l a t e algae. with  The  lower  This i s also consistent  made by C a l v e r t and  309  Ba  P r i c e (1983)  in  the  Namibian Shelf  sediments.  4.4.3.2 ZINC, CHROMIUM, LEAD, COPPER, VANADIUM, AND The showed  analysis that  of  these  the  elements  matter, a f t e r c o r r e c t i o n 4.4.6). T h i s could planktonic by  be due  materials,  settling  surface  correlate  possibly ratios  to  this  sources  major  for t h e i r l a t t i c e - h e l d f r a c t i o n  (section  e i t h e r to t h e i r d i r e c t a s s o c i a t i o n  or to d i a g e n e t i c  studying  elements.  to  elemental  the  This  are  not  sediments,  since  s e v e r a l years of  with  at  the  the mode  sediments  could  seasonal v a r i a t i o n s of t h e i r is,  however,  to sediment samples s i n c e i n t o Saanich I n l e t  more  the  main  vary  from  t h i s i s r e f l e c t e d in t h e i r mineralogy  composition  variations  the  approach  lithogenous materials season and  reactions  F u r t h e r i n d i c a t i o n s on  "excess metal" to  than when a p p l i e d of  strongly  Inlet  to t h e i r scavenging from the water column  be obtained by  ambiguous  season  of  Saanich  organic  particulates,  transport  of  with  anoxic sediment-water i n t e r f a c e . of  sediments  NICKEL  (e.g.  section  4.4.2).  a concern when l o o k i n g  the  at  Such  and  seasonal  correlations  in  samples analyzed represent an average over  deposition.  4.4.3.2.1 ZINC At  station  association  SI-9,  between  (r=0.l8),  probably  dominated  by  its  there  z i n c and because  Q r  no  evidence  for  organic matter at the the  lithogenous  seasonal v a r i a t i o n s i n % C g  is  f l u x of Zn at t h i s fraction  i n the 310  (Fig.  a  45  direct m  level  station  102),  and  s e t t l i n g p a r t i c u l a t e s are  is the not  Fig.  102:  Seasonal v a r i a t i o n s i n the Zn/Fe r a t i o of the settling p a r t i c u l a t e s at s t a t i o n SI-9 (45 m) and SN0.8 (50 m).  311  Fig.  103:  Seasonal the  variations  i n the C  s e t t l i n g p a r t i c u l a t e s at  (45 m)  and  SN0.8 (50  312  m).  /Fe org'  r a t i o of  station  SI-9  large  enough  ratios  (Fig.  SN0.8  (50  to produce 103).  m),  significant variations  However,  concentrations  "excess z i n c " which was  the  deep  b a s i n may  found i n the anoxic  t h e r e f o r e have been added  debris. This i s also i l l u s t r a t e d  sampling)  sediments.  are very s i m i l a r  The  from much  (Fig.  102).  sediments  from  with  i n F i g . 104. The  the s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9 of  Zn/Fe  reach  such an a s s o c i a t i o n becomes apparent  The  their  when c o n s i d e r i n g the r e s u l t s  where organic matter  larger values,  in  planktonic  Zn/Fe r a t i o s of  (averaged over the year  to those found  i n the  underlying  s l i g h t l y higher r a t i o found at 45 m i s c o n s i s t e n t  with the presence of Zn a s s o c i a t e d with p l a n k t o n i c m a t e r i a l s .  No  a d d i t i o n of Zn by d i a g e n e t i c r e a c t i o n s seems necessary to e x p l a i n the  data.  over  May  At s t a t i o n SN0.8, to  August)  the Zn/Fe r a t i o at 50 m  i s much higher  than  in  the  (averaged underlying  sediments. Moreover, s i n c e the Zn/Fe r a t i o at 130 m i s w e l l below the  mixing  l i n e between the s e t t l i n g p a r t i c u l a t e s at 50 m  aluminosilicates  (i.e  %C g=0),  suggests  Qr  present  this  similar,  Zn/Fe  ratio  corresponding  that a l a r g e p r o p o r t i o n of  The  indicating  water column i s minimal. those  a  the  i n p l a n k t o n i c m a t e r i a l s i s r e c y c l e d i n the water  w i t h i n the upper 130 m. very  with  Zn/Fe r a t i o s at 130 m and that z i n c scavenging  The  therefore  that  column  180 m  from the  the the "excess z i n c " 313  are  anoxic  a l s o suggests that there  Zn a d d i t i o n at the sediment-water  to zinc  s i m i l a r i t y between these r a t i o s  from the u n d e r l y i n g sediments  no s i g n i f i c a n t  and  and is  interface,  and  i s indeed a s s o c i a t e d  with  Fig.  104:  Relationship *• corrected)  between Zn/Fe and %C org in  particulates.  314  sediments  and  (salt-  settling  organic  matter.  However,  since  the values  p a r t i c u l a t e s at SN0.8 are summer averages, to  be somewhat higher  than the annual  from  one  the  settling  would expect them  average.  Therefore,  p o s s i b i l i t y that some z i n c i s added to the sediment d u r i n g be  entirely  discounted,  the early  diagenesis  cannot  considering  the l a r g e v a r i a t i o n s i n Zn/Fe r a t i o found w i t h i n  the  SN0.8 c o r e .  Such an a d d i t i o n ,  the  however, i s not  relationship  between Zn/Fe and  68;  4.4.6.5) which does not  section  accumulation  ca.  Q r  of Zn under anoxic  suggests an i.e.  %C g  i n c r e a s e of c a . 1000  >ug  4  supported  by  sediments  i n d i c a t e any  conditions.  5.8x10  Zn per g.  i n Saanich  particularly  This  (Fig.  preferential relationship  Zn/Fe per % organic  carbon,  of organic m a t e r i a l added to  the  sediment. 4.4.3.2.2 CHROMIUM The  chromium  phytoplankton  concentration  seems low.  in  the  organic  In many i n s t a n c e s ,  fraction  v a l u e s below 1  have been reported with a maximum c o n c e n t r a t i o n of 20 ppm and Knauer,  1973).  The  seasonal  variations  was  used i n s t e a d of Mg  the  Mg  the  t r a p m a t e r i a l s at the shallowest  values  however, plankton.  that  f o r the presence of s a l t  in  Saanich  Inlet  in  correcting  Cr  is  105)  (C  with  are c l o s e  vs Cr; r=0.64), much higher values org observed at SN0.8 where p l a n k t o n i c m a t e r i a l concentrations 3  were  suggest,  associated  Although the v a r i a t i o n s seen at s t a t i o n SI-9  to the d e t e c t i o n l i m i t  (Fe  i n the t r a p m a t e r i a l s ) i n  depth ( F i g .  some  ppm  (Martin  in Cr/Fe r a t i o s  because of the d i f f i c u l t y  of  315  105:  Seasonal v a r i a t i o n s i n the Cr/Fe r a t i o of the settling p a r t i c u l a t e s at s t a t i o n SI-9 (45 m) and SN0.8 (50 m).  316  are h i g h e s t . central are  plotted  SI-9 and SN0.8 c o r e s and average t r a p  in F i g .  with  The r e l a t i o n s h i p found  the Cr/Mg r a t i o s  are a l s o found  the SI-9 c o r e .  settling obtained  106.  (Fig.  towards the s i l l ,  The annual  anoxic that than  which i s a l s o r e f l e c t e d  average values obtained  i n the u n d e r l y i n g sediments.  reported  a  from  correlation  between  an  association  between  those  significantly  dissolved  1978;  the  At s t a t i o n SN0.8, however,  In recent s t u d i e s ,  (Cranston and Murray,  suggesting  various  authors Cr i n  Campbell and Yeats,  1981),  this  silica  higher  and  element  and  opaline  The c o i n c i d e n c e between the S i / A l peak ( F i g . 100) and the  Cr/Fe peak ( F i g . 105) at SN0.8 supports t h i s The an  i n the  p a r t i c u l a t e s at s t a t i o n SI-9 are very s i m i l a r t o  values a r e obtained at 50 m.  silica.  materials  58). Values higher  where only the summer average i s presented,  seawater  the  of the c e n t r a l b a s i n (r=0.87) i s very s i m i l a r t o  obtained expected  f o r the SAG samples from  Q r  basin,  sediments  in  Cr/Fe r a t i o s vs % C g  possibility.  s e t t l i n g p a r t i c u l a t e s recovered at g r e a t e r depth have  average  r a t i o which approximately  l i e s on  the  mixing  line  between the 50 m t r a p m a t e r i a l s and a l u m i n o s i l i c a t e s ( F i g . 106). Their  Cr/Fe  ratios  can  therefore  be  explained  by  lateral  a d v e c t i o n of l i t h o g e n o u s m a t e r i a l s and a minimal Cr r e c y c l i n g the  water  ratios  of  suggesting minimal.  column. the  There  i s no s i g n i f i c a n t d i f f e r e n c e  m a t e r i a l s c o l l e c t e d at 130 m  that scavenging However,  due  and  180  in  i n the m,  thus  from the anoxic water column i s a l s o  to  the 317  large  uncertainties  in  each  Ji5Q  31  m  29  27  ~  25  —  23  a1 80'm  -as  21  19  17  130 rrtif' 1 50 m •  SAG ("Shipek* grab)-Central basin  O  Surface sediment (Gravity core)  *  Mean value for labelled core  f~)  Standard deviation about mean value  A  Settling particulates-SI-9 (year average)  A  Settling particulates-SN0.8 (summer average)  15 10  11  12  13  org  Fig.  106:  Relationship  between Cr/Fe and % C  corrected)  in  particulates.  318  sediments  and  Q r g  (saltsettling  measurement  i t i s not  possible  to  distinguish  a d d i t i o n of non-lithogenous Cr i n t o the anoxic  between  the  muds by i t s d i r e c t 3+  association  with p l a n k t o n i c m a t e r i a l s and i t s a d d i t i o n  a d s o r p t i o n at the sediment-water i n t e r f a c e . main in  Cr s p e c i e s i n oxygenated seawater, anoxic  waters (Emerson et a l . ,  be  incorporated  i n the sediments.  Chromate anions, the  a r e reduced t o C r ( O H )  1979).  adsorbed by p a r t i c u l a t e s ( E l d e r f i e l d ,  by Cr  Cr(OH)  is  + 2  1970) and c o u l d  + 2  readily  conceivably  The f a c t that the mixing  line  between the s e t t l i n g p a r t i c u l a t e s and a l u m i n o s i l i c a t e s ( F i g . 106) i s below the sediment r e g r e s s i o n l i n e all  the b i o g e n i c Cr reaching  i n t o the sediments.  (SAG) i m p l i e s at l e a s t  the s e a - f l o o r must be  The Cr/Mg vs %C„„. c o r r e l a t i o n org  that  incorporated i n the anoxic  3  muds  of the deep basin r e q u i r e s an i n c r e a s e of c a . 8x10  per % organic carbon,  i . e . ca.  400;ug Cr per g.  Cr/Mg  4  organic matter  added to the sediments. 4.4.3.2.3 COPPER Although there  the  biophilic  nature  of Cu  i s well-established,  i s not any obvious c o r r e l a t i o n between  production  pattern  collected  at  seasonal  and the Cu/Fe r a t i o s of s e t t l i n g p a r t i c u l a t e s  45 m at s t a t i o n  SI-9  ( F i g . 107). Moreover,  a d d i t i o n to the sediment d u r i n g e a r l y d i a g e n e s i s to  explain  settling  the data a t t h i s s t a t i o n ,  particulates  sediments ( F i g . 108). the  deep  basin  primary  i s similar  i s not necessary  s i n c e the  t o that  of  Cu/Fe the  Such an a d d i t i o n to the anoxic  is,  however, 319  strongly  Cu  of the  underlying  sediments of  suggested  by  the  SI-9 (45 +NaN  A  Fig.  107:  S  O  N  D  J  F  M  A  M  J  m) 3  J  A S  Seasonal v a r i a t i o n s i n t h e Cu/Fe r a t i o o f the s e t t l i n g p a r t i c u l a t e s a t s t a t i o n SI-9 (45 m)  320  32  Fig. 3  108:  Relationship sediments values  between  Cu/Fe  and s e t t l i n g  for settling  salt-corrected).  321  and  %C_ org  particulates  particulates  (  were  in % c o r g  not  r e l a t i o n s h i p between % C g and Cu/Mg ( S e c t i o n 4.3.2.6.6; F i g . 72) Q r  or Cu/Fe ( F i g . This  is  108), as both have an i n t e r c e p t on the C  supported by the data presented by Jacobs  and  Q r  g  axis.  Emerson  (1982) which show a d e p l e t i o n of Cu w i t h i n the anoxic zone of the water  column  in  Saanich I n l e t .  Indications  of  whether  a d d i t i o n occurs w i t h i n the water column or at the interface,  however,  composition abnormally (Appendix  of  the  high  cannot  be  settling  values  were  obtained  found  in  sediment-water  from  particulates  the  at  some  this  elemental  SN0.8. of  the  Some samples  IV-3) and contamination i s suspected.  4.4.3.2.4 VANADIUM As f o r the other t r a n s i t i o n metals, there are no from the seasonal v a r i a t i o n s concentrations influenced values  i n the V/Fe  r a t i o s that the vanadium  i n the s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9  by p l a n k t o n i c m a t e r i a l s  found  indications  in  the  (Fig.  109).  Moreover,  summer samples at SN0.8 (50  m)  are  are the not  s i g n i f i c a n t l y h i g h e r , thus i n d i c a t i n g that although a s i g n i f i c a n t enrichment the 60),  (and c o r r e l a t i o n with organic carbon) was  anoxic sediments V  is  materials. stations  are  significant sediment  was  (Section  not d i r e c t l y added to the sediment The  underlying  of Saanich I n l e t  V/Fe  4.3.2.6.4, with  in Fig.  planktonic  r a t i o s of the s e t t l i n g p a r t i c u l a t e s at both  significantly sediments  found  lower  (Fig.  110)  than thus  those  found  suggesting  in that  the a  f r a c t i o n of the e x t r a non-lithogenous V i n the anoxic added d u r i n g e a r l y d i a g e n e s i s at the 322  sediment-water  SI-9  •  NaN.  SN0.8  + NaCl  o  V J  A  109:  S  O  N  D  J  F  M  A  M  J  J  A S  Seasonal v a r i a t i o n s i n the V/Fe r a t i o of the s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9 (45 m) and SN0.8 (50 m).  323  ••.180 m 45 m  50 m  130 m  SAG ("Shipek" grab)-regression line Surface sediment (Gravity core) Mean value for labelled core •  Standard deviation about mean value  A  Settling particulates-SI-9 (year average)  •  Settling particulates-SN0.8 (summer average)  6 org  Fig.  110:  Relationship  8  10  (%)  between  V/Fe  and  %  o  r  g  (  f o r s e t t l i n g p a r t i c u l a t e s were  salt-corrected).  324  *  c  sediments and s e t t l i n g p a r t i c u l a t e s values  11  % c o r  n  g  not  interface. A often  geochemical a s s o c i a t i o n between V and organic matter been  Gieskes,  reported  1983).  vanadyl  (e.g.  The reduction 2+  c a t i o n s (VO  conditions,  Goldschmidt, of  1954;  with  subsequent  Brumsack  vanadate ions  ) by humic substances formation  2  and Weber,  1979;  reactions  could  interface.  Moreover,  conditions  Templeton and  conceivably  have  occur  environmental  vanadyl  Chasteen, at  the  to  4  organic  complexes, has been demonstrated (e.g. Szalay and S z i l a g y i , Wilson  and  (H VC> ~)  under of  has  1967;  1980).  Such  sediment-water  s i n c e humic substances formed under anoxic  a  stronger  reducing  capacity  than  their  c o u n t e r p a r t s formed i n more o x i d i z i n g environments (Chapter 1), V uptake  by organic m a t e r i a l s c o u l d be more pronounced  sediments.  Alternatively,  vanadate  could  a l s o be  vanadyl i n anoxic waters (e.g. van der S l o o t et a l . , H V0 ~ + 4H  + 1e"  +  o  2  Q  i . e with a pE = -4  ==  V0  2 +  [VO,-] |-- = c a . [VO^ ]  } pH = 7.4  + 3H 0 o  in  anoxic  reduced  to  1985), v i z  E =1,000 mv O  2  -  0.05  2+ At  seawater pH,  VO  h y d r o l y z e s and forms i n s o l u b l e  hydroxides  (e.g. F r a n c a v i l l a and Chasteen, 1975), v i z V0  2 +  + 20H~  --->  V0(0H)  ,* 2 ( S) o  which c o u l d p o s s i b l y accumulate i n anoxic sediments. 4.4.3.2.5 NICKEL The suggest  seasonal that  variations  relatively  of Ni/Fe at s t a t i o n SI-9  l e s s 325 Ni reaches  the  sediment  (45  m)  during  spring  and  summer ( F i g .  while Ni was SN0.8,  111) compared with the  winter months,  b a r e l y d e t e c t a b l e i n the summer samples c o l l e c t e d at  thus  suggesting  that  this  element  associated  with p l a n k t o n i c m a t e r i a l s .  indication  that n i c k e l was  scavenged  is  Moreover,  not  directly  there  was  no  from the water column ( F i g .  112). A l l t h i s , t h e r e f o r e , s t r o n g l y suggests that the i n c r e a s e i n Ni  c o n c e n t r a t i o n found in the anoxic sediments of Saanich  ( s e c t i o n 4.4.6.3; F i g . 54)  i s the r e s u l t  Inlet  of an a d d i t i o n of Ni v i a  r e a c t i o n s o c c u r r i n g at the sediment-water  interface,  and not  due  to i t s d i r e c t a s s o c i a t i o n with p l a n k t o n i c organic matter. Fig. %Fe a  112 suggests that c a . 2-5  ( i . e . c a . 6-15 sediment  ppm)  ppm  of non-lithogenous Ni per  are added to the sediment  at SN0.8, with  accumulation r a t e of 95 mg/cm .yr (Table  35).  This  corresponds to a non-lithogenous accumulation r a t e of c a . 0.6 2 1.5 jjg/cm . y r . The n i c k e l c o n c e n t r a t i o n i n seawater i s c a . 0.35 3 ng/cm  (Jacobs and Emerson,  should  therefore  1982).  The Ni added to the  decrease the Ni c o n c e n t r a t i o n i n the  sediment isolated  body of water i n the deep b a s i n of Saanich I n l e t by 30-40%. a decrease was  Such  not, however, observed i n the water column p r o f i l e  of Jacobs and Emerson (1982).  T h i s c o u l d p o s s i b l y be due t o  the  addition  of Ni i n t o the anoxic water by scavenging from the oxic  zone  manganese  by  suggested The  oxides,  via a  mechanism  similar  to  that  f o r Mo  (Berrang and G r i l l ,  lower  Ni/Fe r a t i o s found i n the s e t t l i n g m a t e r i a l s 326  1974). at  SI-9  . + NaN  SN0.8  •  3 NaN  no  3  A  Fig.  S  O  N  D  J  F  M  A  M  J  J  A S  I l l : Seasonal v a r i a t i o n s i n the Ni/Fe r a t i o of the s e t t l i n g p a r t i c u l a t e s at s t a t i o n SI-9 (45 m) and SN0.8 (50 m).  327  18  16  14  12  10  •o  •  SAG ("Shipek" grab)-Central basin  O  Surface sediment (Gravity core)  *  Mean value for labelled core  180 m 130 m  l~l  Standard deviation about mean value  A  Settling particulates-SI-9 (year average)  •  Settling particulates-SN0.8 (summer average)  ik50 m 10  6 org  Fig.  112:  Relationship sediments values  between  (%)  Ni/Fe  and  %  and s e t t l i n g p a r t i c u l a t e s  for settling  salt-corrected).  328  1 1  particulates  *  c o r g  (  were  n  % c o r g  not  station 111)  SI-9  during  summer compared to the winter  samples  suggest that the l i t h o g e n o u s m a t e r i a l s c o l l e c t e d  (Fig.  in  summer  are r e l a t i v e l y poor i n Ni compared to the m a t e r i a l s brought the  inlet  from the nearby catchment area by winter  s i m i l a r decrease i n the Cu/Fe, lithic  fraction  could  Cr/Fe,  and  into  run-off.  Zn/Fe r a t i o s of  e x p l a i n the lack of  indications  this of  a s s o c i a t i o n between p l a n k t o n i c m a t e r i a l s and v a r i o u s metals Cu,  Cr,  Zn/Fe have  Zn)  at SI-9,  ratios  due  where an  metals  and  could  been masked by a simultaneous decrease i n the r a t i o s of  lithogenous  an  (e.g.  i n c r e a s e i n the Cu/Fe, Cr/Fe,  to a d d i t i o n of o r g a n i c a l l y - h e l d  A  the  fraction.  4.4.3.3 MOLYBDENUM Of enrichment  a l l the elements analyzed, in  the  anoxic  Mo  showed  sediments of Saanich  the  strongest  Inlet  (section  4.4.6.7). The Mo stations in  concentration  were a l l found to be below d e t e c t i o n l i m i t  the m a t e r i a l c o l l e c t e d  (Appendix added  i n the s e t t l i n g p a r t i c u l a t e s at both  IV-3).  in the deepest t r a p at SN0.8  This observation  to the anoxic  (5 ppm)  even  (180  m)  i n d i c a t e s that molybdenum  is  sediments by r e a c t i o n s o c c u r r i n g below  180m,  presumably at the sediment-wa-ter i n t e r f a c e . At  SN0.8,  the . r a t e  of  accumulation  calculated, viz 2 S  M  q  = 0.1  g/cm  .yr x 100 2  = 10 jug/cm .yr 329  ug/g  of  Mo  can  be  The Mo c o n c e t r a t i o n i n seawater  i s ca.  10 n g / l ;  an accumulation would represent the removal 20%  of  the Mo  decrease may  over one year of 10-  present i n the bottom water  oxides (Berrang and G r i l l , Various  mechanisms  A  however,  i t i s also  1974). have  been proposed  of  precipitated  as MoSg with the FeS formed at  (Korolev,  water,  inlet.  from the oxic water by manganese  accumulation  interface  Mo  the  s i n c e there a r e i n d i c a t i o n s that  added t o t h i s zone by scavenging  that  of  of the Mo c o n c e n t r a t i o n i n the anoxic  not be apparent  t h e r e f o r e , such  i n anoxic  sediments.  to  explain  I t could the  the  be co-  sediment-water  1958; B e r t i n e , 1972). I t was a l s o  suggested  MoO^~ c o u l d be reduced t o MoC>2 i n anoxic waters  (Bertine,  +  1972). T h i s c a t i o n i c s p e c i e s c o u l d then be subsequently by n e g a t i v e l y - c h a r g e d p a r t i c u l a t e s . bound  molybdenum  (Contreras et a l . ,  i n the pore  scavenged  The presence of o r g a n i c a l l y waters  of  anoxic  1978; Brumsack and Gieskes,  sediments  1983; Malcolm,  1985),  the l a r g e Mo c o n c e n t r a t i o n found i n the humic f r a c t i o n of  anoxic  sediments  Morris, these  1977; C a l v e r t o r g a n i c molecules  support used 1958,  (Nissenbaum  and  et a l . ,  t o reduce MoO^  1972b),  two p o s s i b i l i t i e s awaits f u r t h e r  (Szilagyi,  however,  e x t r a c t humic m a t e r i a l s ,  Volkov and Fomina,  1976; C a l v e r t  1985) and the known a b i l i t y  t h i s second h y p o t h e s i s ;  to  Swaine,  and of  1967) would  s i n c e NaOH  solutions  a l s o d i s s o l v e MoS^  (Korolev,  the d i s t i n c t i o n between these  investigation. It i s interesting  330  to  note the l a r g e d i f f e r e n c e  i n Mo  concentration  the cores c o l l e c t e d at SI-9 and SN0.8 (which the SAG SI-9  in sulphide minerals,  station  due  (Appendix  i s also r e f l e c t e d in  very l i t t l e Mo  IV-2.2).  accumulates  The d i f f e r e n c e cannot  be  at  only  to d i l u t i o n by a higher input of l i t h o g e n o u s m a t e r i a l s ;  sedimentation  rate  at SI-9  (Table 35), so that i f Mo least  30 ppm  accumulation  Mo  i s l e s s than 3 times that  were accumulating  should be found at SI-9.  r a t e must t h e r e f o r e r e f l e c t  although deposited  sediments  under  more  are e n t i r e l y oxidizing  r a t e , at in  Mo  environment  to i t s higher degree of f o r longer p e r i o d s  anoxic towards the head of the i n l e t . the  the  SN0.8  The d i f f e r e n c e  i s o l a t i o n , the water column i s more o f t e n , and time,  at  at a s i m i l a r  the chemical  i n which the sediments are d e p o s i t e d . Due  of  between  samples ( F i g . 74)). Even though the sediment d e p o s i t e d at  is rich  this  found  anoxic,  conditions.  Near the they  sill,  are  often  Therefore,  more  permanent anoxic c o n d i t i o n s i n the water column seem necessary  to  occasion  or  the  alternatively,  accumulation Mo  of  Mo  section  of  compared  SN0.8  sediments;  to SN0.8 (Appendix  molybdenum  after  the  contact  concentration intensive  renewed the bottom water (Powys,  before the f l u s h i n g , supports t h i s The  of lower Mo  a core c o l l e c t e d  f l u s h i n g which completely comm.),  anoxic  i s r e l e a s e d from anoxic sediments i n  with oxygenated water. The presence upper  in  accumulation  IV-2.4) which was  1984 pers.  collected  possibility. rate  calculated  for  station  suggests that t h i s type of anoxic environment can be 331  in  very  important  for  the geochemical  balance of Mo  in  seawater.  The 9  river g/yr  input  of d i s s o l v e d Mo  (Martin and W h i t f i e l d ,  has been estimated at  an area of c a .  Persian  Gulf).  concentration record,  it  18x10  i n Saanich I n l e t at s t a t i o n 2  km  SN0.8  ( i . e . l e s s than the area of the  Therefore,  if  the  history  of  i n seawater c o u l d be deduced from the  the  Mo  sedimentary  c o u l d be a very s e n s i t i v e i n d i c a t o r of the extent of  anoxic environments should  18x10  1983). Such an input c o u l d be matched  by a removal of the type found 4 over  ca.  i n the past,  and  the absence of any  signal  r u l e out the p o s s i b i l i t y of the occurrence of anoxia  in  the water column over e x t e n s i v e a r e a s .  A b e t t e r understanding  of  the  in  is  mechanism  required,  of  however,  i n d i c a t o r can be The in  accumulation before  of Mo  the  usefulness  of  sediments this  potential  assessed.  high Mn c o n c e n t r a t i o n s (1.3 - 1.4%  the deepest  anoxic  t r a p s at s t a t i o n SI-9  Mn)which were  i n September 1984  ought  have  been a s s o c i a t e d with a measurable amount of Mo  (ca.  ppm;  Berrang  of  seawater  by Mn  (Berrang  and  and  Grill,  oxides was Grill,  1974) clearly  1974).  s i n c e scavenging indicated  However,  10  Mo  i n a previous  no molybdenum  d e t e c t e d i n these samples ( d e t e c t i o n l i m i t : 5  found to -15 from study  could  be  ppm).  4.4.3.4 RUBIDIUM The  Rb/K  r a t i o s obtained from the a n a l y s i s of the  p a r t i c u l a t e s at SI-9 and SN0.8 are very s i m i l a r 332  settling  ( F i g . 113),  thus  r — i — i  A  Fig.  S  O  1  N  SI-9  .  SN0.8  + no  1  D  J  +NaN  3  NaN  i  1  1  1  i  i  i  F  M  A  M  J  J  A  i  S  113: Seasonal v a r i a t i o n s i n the Rb/K r a t i o of the settling p a r t i c u l a t e s at s t a t i o n SI-9 (45 m) and SN0.8 (50 m).  333  confirming  that a l u m i n o s i l i c a t e s are the main rubidium  carrier.  There seems t o be a minimum i n the Rb/K r a t i o i n s p r i n g which may i n d i c a t e a d i f f e r e n t source of lithogenous  materials.  4.4.3.5 ZIRCONIUM The  Zr/Al  r a t i o s of the m a t e r i a l s  collected in  summer  at  s t a t i o n SN0.8 a t 50 m are s i g n i f i c a n t l y higher than those of materials  collected  possible  at  SI-9  ( F i g . 114),  thus  a s s o c i a t i o n of some Zr with p l a n k t o n i c  result requires  the  suggesting  materials.  a  This  further investigation.  4.4.3.6 MANGANESE The at  f l u x e s of Mn a s s o c i a t e d  both  stations  established  show  deployed  boundary  clearly  the  influence  redox chemistry of t h i s element.  the year of sampling, traps  with the s e t t l i n g  (Fig.  at  the h i g h e s t mid-depth,  particulates of  the  well-  Throughout most  Mn f l u x was i n t e r c e p t e d  i . e . c l o s e to  the  of  by the  oxic/anoxic  115). T h i s , very probably, r e f l e c t s the formation 2+  of  manganese oxides from Mn  into  the oxic water.  renewal  of  collected 150  m)  present  m  In August and September,  bottom water,  throughout  just  very l a r g e amounts  zone  after of  Mn  the were  the water column at SI-9 ( p a r t i c u l a r l y a t 2+  r e s u l t i n g from the o x i d a t i o n  and p r e c i p i t a t i o n  of  Mn  i n the upwelled anoxic water.  The 150  the  d i f f u s i n g up from the anoxic  Mn/Fe r a t i o s of the s e t t l i n g p a r t i c u l a t e s c o l l e c t e d at  underlying  SI-9 were i n v a r i a b l y higher than sediment  the  ratio  of  at the  ( F i g . 115), suggesting t h a t , although a l a r g e 334  F i g . 114:  Seasonal v a r i a t i o n s i n the Z r / A l r a t i o of the settling p a r t i c u l a t e s at s t a t i o n SI-9 (45 ra) and SN0.8 (50 m).  335  4000 SI-9 .  2000  . 45 m  • - -+ 110 m •  1000  • 150 m  800  600  400  200  - i sed. A  3.  S  O  N  D  J  F  M  A  M  J  J  A  S  115: S e a s o n a l v a r i a t i o n s i n t h e Mn/Fe r a t i o of the settling particulates at s t a t i o n SI-9 and SN0.8 ( r e c o v e r e d i n t h e p r e s e n c e o f NaN^).  336  fraction  of ' the  solubilized before  manganese oxides  i n the anoxic  being  formed at the  sediment  r e c y c l e d to the water column.  This i s  d i s s o l v e d and  i n the deepest t r a p s were very  underlying  is  water column, some reaches the  i n c o n t r a s t with the data c o l l e c t e d from SN0.8, ratios  redoxcline  sediment, suggesting  that  where the  Mn/Fe  s i m i l a r to the r a t i o of , in t h i s part of the  the  inlet,  most of the oxide d i s s o l u t i o n occured i n the water column. Very o f t e n , s i g n i f i c a n t l y more Mn poisoned was  with NaN^  (Appendix IV-3,  remobilized  from  the  was  c o l l e c t e d i n the  F i g . 116)  materials  traps  i n d i c a t i n g that  collected  Mn  without  preservatives. 4.4.4  FLUXES OF The  monthly f l u x e s of i o d i n e at s t a t i o n SI-9  reported A  IODINE  i n Appendix seasonal  and  SN0.8  are  IV-3.  p a t t e r n can be observed i n the I/C  ratio  of  org the  settling  p a r t i c u l a t e s c o l l e c t e d at SI-9  r a t i o i s s i g n i f i c a n t l y higher beginning  of  materials  (e.g.  Bowen,  1979; o r  was  interpreted organic  and  the s p r i n g bloom to values  occurrence of a high ! / C g ratio  i n winter  t y p i c a l for al.,  is puzzling.  a l s o measured i n these samples ( F i g . as  r e f l e c t i n g the  inlet  337  by  winter  This the  planktonic 1981).  The  A higher  C/N  82)  l a r g e r p r o p o r t i o n of  matter brought i n t o the  117).  drops s h a r p l y at  E l d e r f i e l d et  i n winter  (Fig.  which  was  terrestrial  run-off.  Such  SN0.8 (130 .  3000 -  . + NaN  +—+  >  m)  o  no N a N _  2000  T3  CM  X 3  1000-  /\ / \ / \  0 A S  Fig.  116:  O N  D  J  F  M A  M  J  J  A S  Comparison between t h e Mn f l u x e s measured a t s t a t i o n SN0.8 (130 m) w i t h and w i t h o u t NaN^ poisoning.  338  F i g . 117:  Seasonal v a r i a t i o n s  i n the  I/CJ  r a t i o of  the  org settling  particulates  SN0.8.  339  at  station  SI-9  and  m a t e r i a l s would, ratio  however,  ( c a . 0.1x10 ;  Bowen,  4  section  4.5.1.1)  materials  be expected to have a very  that  collected  1979).  the  oxic  e x p l a i n the seasonal s p r i n g and summer,  I/C ratio org ( s e c t i o n 4.3.2.7), t h e i r re-suspension  than  higher  the l a t e r a l l y - a d v e c t e d organic m a t e r i a l seems f r e s h plankton,  low J / C Q  and thus would  ratio. the I/C of org  s e t t l i n g p a r t i c u l a t e s i n v a r i a b l y i n c r e a s e s between 45 m  suspension The  I / / C  as  °^  displacement Similarly, J/CQJ.  suggested  t  of  h  some  to  important lends  of I-enriched sediment  there  sill  also  of t h i s i o d i n e d u r i n g  at s t a t i o n SN0.8,  June, at  support  zone ( i . e .  1984).  or r e -  sediments.  suggests  early  increase i n  followed by a  between 130 m and 180 m,  Since l a t e r a l advection  t h i s s t a t i o n ( s e c t i o n 4.5.1.2),  the  diagenesis.  i s a significant  r a t i o between 50 m and 130 m, apparently  decrease i n the anoxic March  by Malcolm and P r i c e (1984)  underlying  e  and  the uptake of i o d i n e by s e t t l i n g  and l a t e r a l a d v e c t i o n  org  could  v a r i a t i o n s I/C r a t i o observed at SI-9. In org  117 a l s o i n d i c a t e s t h a t , at s t a t i o n SI-9,  particulates  in  from the s i l l  a much  110 m. T h i s c o u l d e i t h e r r e f l e c t  the  organic  Since  be expected to have a r e l a t i v e l y  the  (see  sediments.  to c o n s i s t p r i m a r i l y of r e l a t i v e l y  Fig.  at  g  SI-9  have  traps  the  o r  station  sediments  planktonic materials  f r a c t i o n of  sediment  c o n s i s t s of re-suspended m a t e r i a l s these  I t has been argued  a significant  in  low l / C  i s much  this  from less  observation  to the p o s s i b i l i t y of i o d i n e uptake by p a r t i c u l a t e s  oxic seawater,  with  subsequent r e l e a s e i n the 340  anoxic  zone,  p o s s i b l y v i a the mechanism suggested  i n Chap.  3.  Alternatively,  i o d i n e uptake c o u l d a l s o occur at the o x i c / a n o x i c boundary i n the water  column,  could  then  1986).  where iodate c o u l d be reduced by l ^ S to 1^  r e a c t with organic matter  More  work  i s necessary to  (Jia-Zhong and distinguish  which  Whitfield,  between  these  possibilities.  4.5 CONCLUSIONS The chemical composition of Saanich I n l e t has i n d i c a t e d many  t r a c e metals a r e e n r i c h e d i n the anoxic ooze found  central  sources  variations  in  particulates  ( s e c t i o n 4.3.2.6.9).  the  chemical  collected  with  S p a t i a l and  composition interceptor  of traps  from  seasonal  the  settling  gave  further  i n d i c a t i o n s of the mode of i n c o r p o r a t i o n of these metals anoxic  of the  basin of the i n l e t over the p o s s i b l e c o n t r i b u t i o n s  lithogenous  that  i n these  sediments.  B i o g e n i c Ba and Cr seem t o be mainly a s s o c i a t e d with o p a l i n e silica,  although  particularly in  the  alternative  f o r Ba.  anoxic  explanations are  also  possible,  These two metals, however, a r e not e n r i c h e d  sediments  because  their  concentration  i n the  b i o g e n i c phase i s lower than i n the l i t h i c m a t e r i a l s . Zinc  seems t o be added to the sediment  organic matter. There adsorbed  from  i s no i n d i c a t i o n that  in association  i t i s p r e c i p i t a t e d or  the anoxic water column or at the 341  with  sediment-water  interface. matter  On the other hand, the a s s o c i a t i o n of Cu with organic  alone cannot  Saanich  Inlet.  directly  explain  i t s distribution  i n the sediments  T h i s element must a l s o be added v i a a  linked  to  the  anoxic  conditions  of  mechanism  present  in  this  environment. Similarly, reactions  N i , V,  occurring  and  at the  Mo are added t o these sediments by sediment-water  studied  here,  interface.  nearshore  environment  these  associated  t o any s i g n i f i c a n t extent with p l a n k t o n i c  metals  p a r t i c u l a r l y N i and Mo.  Of a l l the elements  the  i n the anoxic sediments  largest  enrichment  In the  materials,  analyzed, of  are not  Mo showed  the  central  ba s i n. Nearshore constitute compared  impact  deposited  very important  with  (Calvert, anoxic  a  sediments  their  1976).  anoxic  conditions  sink f o r v a r i o u s t r a c e metals  accumulation  Therefore,  under  rates  in  pelagic  when  sediments  v a r i a t i o n s i n the a r e a l extent  of  b a s i n s over g e o l o g i c a l times c o u l d have had a s i g n i f i c a n t on the seawater  concentrations  could  c o n c e n t r a t i o n s of these metals. be  deduced from  the  If  sedimentary  these record  ( p o s s i b l y from the metal content of m i c r o f o s s i l s i n a way s i m i l a r to  that  used  to  Atlantic  Deep  Water  Keigwin,  1982);  to  deduce the Cd over  concentrations  the past 200,000  in  years  the (Boyle  North and  Emerson p e r s . comm.), the r e s u l t s c o u l d be used  estimate the occurrence of anoxic basins i n  342  the  past.  More  information  on  the  mode of i n c o r p o r a t i o n of  trace  metals  in  sediments (both o x i c and anoxic) i s r e q u i r e d , however, before the p o t e n t i a l of t h i s approach can be adequately  343  assessed.  5.  Although  the  CONCLUDING REMARKS.  three problems which were addressed  in  this  t h e s i s are c l e a r l y d i s t i n c t , t h i s work confirms the a l r e a d y w e l l e s t a b l i s h e d importance of humic substances i n many  environmental  processes. It  was demonstrated  significant  role  in  that these complex polymers can play  the  sulphur  geochemistry  of  a  nearshore  sediments. The uptake of sulphur by humic m a t e r i a l s has a b e a r i n g not  only  on  additional  the geochemical c y c l e of sulphur by  mechanism  whereby  sulphur can  be  providing  removed  an  to the  sediments, but a l s o , p o s s i b l y , on the geochemical c y c l e s of other elements.  It  complexing  was  shown  capacity  of  Similar e f f e c t s are l i k e l y influence  their  displacement  of  that S - a d d i t i o n  humic substances with  increase  respect  t o Cu.  in  anoxic  from the humic matrix  sediments. by  surficial  The oxic  high  concentration  sediments  of t h i s element  c o u l d a l s o be  due  a b i l i t y of these u b i q u i t o u s o r g a n i c molecules. also  be  implicated  i n the removal of c e r t a i n  to  The  nucleophilic  sulphur s p e c i e s may e x p l a i n the behaviour of i o d i n e d u r i n g diagenesis.  the  to be found f o r other metals and c o u l d  accumulation iodine  could  early  found  in  the reducing  T h i s p r o p e r t y may metals  such  as  vanadium and molybdenum to the sediments. The  role  of humic m a t e r i a l s i n the i n c o r p o r a t i o n of  344  trace  metals  i n marine sediments  study.  However,  the  was  geochemical  d i r e c t l y addressed  of  some t r a n s i t i o n  and the importance  c y c l e of these elements  in  this  metals  into  of t h i s process f o r  have been  examined.  It  shown that Ba, Cr, Zn, Pb, Cu, N i , V, and Mo were e n r i c h e d i n  the anoxic ooze found intermittently Columbia.  It  i n the c e n t r a l basin of Saanich  anoxic was  fjord  Inlet,  s i t u a t e d on the coast  of  V,  and Mo),  the sediment-water  the enrichment  an  British  a l s o d i s c o v e r e d that f o r some of these  (particularly Ni, at  not  removal  nearshore anoxic sediments the  was  metals  occurs p r i n c i p a l l y phase  of  d i a g e n e s i s . I t i s not known at t h i s stage i f humic substances  are  directly  implicated  potential sulphur  as by  suggests  i n t e r f a c e d u r i n g the very e a r l y  i n the enrichment  metal complexers, reactions  that  they  behaviour of these metals Humic  materials  have an  i n such  may  However,  p a r t i c u l a r l y when  with reduced  could  processes.  inorganic  the  roles  in  the  environments.  have two  conflicting  part,  metal  which  sediment-water important invoked  could  accumulation  interface.  forming  This  process  could  higher In  soluble  than  be  predicted  t h i s context, 345  from  i n pore  in  metal at  the  especially  where metal complexation  e x p l a i n the occurrence of metals  concentrations solubilities.  by  They may,  be r e l e a s e d to the water column  i n anoxic sediments, to  species, on  i n c o r p o r a t i o n i n marine sediments.  complexes  in  bearing  process of metal prevent  enriched  sulphur  important  their  has been  waters  their  the sulphur enrichment  at  sulphide of humic  polymers,  demonstrated  significance.  On  accumulation increasing  actual  environment and  mineral  the  role  of  binding  i n the  or c l a y m i n e r a l s .  metal  considered The  and  anoxic  sites  of  particular  environments  available  substances  in  for  any  by  metal  particular  between t h e i r  a l s o on competition sediments,  such as  soluble  with  various  oxyhydroxides,  T h e i r s i g n i f i c a n c e w i l l depend the r e l a t i v e abundance of the  environmental c o n d i t i o n s  m a t e r i a l s were formed may their  be  a l s o enhance the metal  depend upon competition  components and  phases i n v o l v e d .  for  hand, they may  of humic  phases present  sulphides  may  s o l i d phase.  will  insoluble  work,  both in oxic and  number  a d d i t i o n onto the The  this  the other  process the  in  a l s o be a very  complexing p r o p e r t i e s .  various  i n which the humic  important  Humification  o x i c c o n d i t i o n s y i e l d a substance r e l a t i v e l y  upon  rich  consideration  processes in  under  O-containing  f u n c t i o n a l groups which are produced by the o x i d a t i v e cleavage of the  organic  macromolecules.  These f u n c t i o n a l groups may  very  e f f i c i e n t at complexing t r a c e metals in the presence of much 2+  larger concentrations anoxic c o n d i t i o n s , and  instead  discussed the  capacity  of  and Mg  .  On  the other  the a d d i t i o n of such groups w i l l is  likely  the presence of sulphur  s t r u c t u r e can  increase  these m a t e r i a l s  be  2+  a substantial S-addition  already,  humic  of Ca  not  to  be  prevented occur.  As  f u n c t i o n a l groups i n  substantially  the  by p r o v i d i n g complexing 346  hand, under  complexing sites  for  which c o m p e t i t i o n by the major c a t i o n s i s expected to be minimal. F u r t h e r work i s needed on these very complex problems. is  little  doubt  geochemical nearshore  that humic m a t e r i a l s w i l l be important  processes, sediments.  some of these  especially  in  moderately  i n many  organic-rich  This thesis provides a s t a r t i n g point  investigations.  347  There  for  6. Ackermann,  F.  effect  (1980)  in  S.  A procedure  (1966)  S.,  estuarine  and  Factors  Chatt,  c o n t r i b u t i n g to  and bonding  J.,  (b)-behaviour  and Davies,  Chem. Soc. London. Q. Rev. G.R.,  McKnight,  (1985)  An  D.M.,  N.R.  (1958) The r e l a t i v e  sediment, and Water. In  P. MacCarthy),  pp  to  humic  1-12.  in  in S o i l ,  Mcknight, R.L.  soil,  Sediment,  Wershaw, and  and N u t t e r , J r .  (1974)  Elemental mercury e v o l u t i o n mediated by humic  Science  184,  Anderson,  Schnepfe,  M.M.,  S i l b e r , C.C.,  i n c o a l . Science 221, J . J . , and  Saanich  Inlet,  Coast. Mar. Antweiller, tertiary  R.C,  acid.  and Simon,  S u l f u r d i a g e n e s i s i n Everglades peat and  pyrite  D.E.  895-897.  Z.S.,  (1983)  P.  Wiley.  A l b e r t s , J . J . , S c h n i d l e r , J.E., M i l l e r , R.W.,  Altschuler,  ions.  and MacCarthy,  substances  Humic Substances  Aiken, D.M.  and  265-276.  Wershaw, R.L.,  introduction  and water (eds. G.R.  12,  in  1, 207-220.  a f f i n i t i e s of l i g a n d atoms f o r acceptor molecules  Aiken,  coastal  E n v i r o n . Tech. L e t t . 1, 518-527.  acceptors. Structure Ahrland,  f o r c o r r e c t i n g the g r a i n s i z e  heavy metal analyses of  sediments. Ahrland,  BIBLIOGRAPHY  Devol,  A.H.  origin  F.O. of  221-227. (1973) Deep water renewal  an i n t e r m i t t e n t l y anoxic  basin.  Est.  in and  S c i . 1,1-10. and Drever, J . I . (1983) The weathering  volcanic  ash:  Importance 348  of  organic  of l a t e solutes.  Geochim. Cosmochim. Acta 47, 623-629. Baker,  W.E.  (1973)  podzolic  The  soils  role  in  of humic  mineral  acids  from  degradation  Tasmanian  and  metal  m o b i l i z a t i o n . Geochim. Cosmochim. Acta 37, 269-281. Banse, K. (1974) On the i n t e r p r e t a t i o n of data f o r the carbon-ton i t r o g e n r a t i o of phytoplankton.  Limnol.  Oceanogr. 19,695-  699. Barber,  R.T., and Ryther, J.H. (1969) Organic c h e l a t o r s : F a c t o r s  affecting  primary  production  in  the  Cromwell  current  u p w e l l i n g . J ^ Exp. Mar. B i o l . E c o l . 3, 191-199. Barry,  B.M.  (1967)  scattering,  Diel  mostly  vertical  migrations  i n Saanich I n l e t ,  of  underwater  B.C. Deep-Sea Res. 14  35-50. B a r t l e t t , J.K., and Skoog, D.A. (1954) C o l o r i m e t r i c d e t e r m i n a t i o n of elemental s u l f u r  i n hydrocarbons.  Anal.  Chem. 26, 1008-  1011. Beckwith  R.S.  Nature Benesi,  (1959)  H.A.,  and  hydrocarbons.  at  R.A. low  organic  matter.  184, 745-746.  investigation  Berner,  T i t r a t i o n curve of s o i l  H i l d e b r a n d J.H. of  (1949) A spectrophotometric  the i n t e r a c t i o n of i o d i n e  with  aromatic  Am. Chem. Soc. J . 71, 2703-2707.  (1964) Iron s u l f i d e s formed from aqueous s o l u t i o n s temperatures  and  atmospheric  72, 293-306.  34.9  pressure.  J_^ G e o l .  Berner,  R.A.  (1969)  anaerobic 267, Berner,  Migration  of  iron  and  sulphur  sediments d u r i n g e a r l y d i a g e n e s i s .  Am.  within J.  Sci.  19-42. R.A.  (1984)  Sedimentary  p y r i t e formation:  An  update.  Geochim. Cosmochim. Acta 48, 605-616. Berner,  R.A.,  and  and R a i s w e l l ,  R.  (1983) B u r i a l of o r g a n i c carbon  p y r i t e sulphur i n sediments  new  over Phanerozoic  times:  a  theory. Geochim. Cosmochim. Acta 47, 855-862.  Berrang,  P.G.,  oxide  and G r i l l ,  scavenging  Columbia. Mar. Bertine,  K.K.  Bertine,  K.K.,  (1974) The e f f e c t of manganese  on molybdenum i n Saanich  Chem. 2,  (1972)  waters. Mar.  E.V.  M.,  The d e p o s i t i o n of  molybdenum  and T u r e k i a n ,  van der L i n d e ,  and Takken, H.J.  fatty  aldehydes,  K.K.  iodine  anoxic  (1973) Molybdenum i n marine  L.M.,  1415-1434.  de V a l o i s ,  P.J., Van  Dort,  (1974) Organic s u l f u r compounds from  hydrogen  sulfide,  t h i o l s and ammonia  f l a v o r c o n s t i t u e n t s . J ^ Aqr. Food Chem. 22, R.,  in  Chem. 1, 43-53.  H.M.,  Bojanowski,  British  125-148.  d e p o s i t s . Geochim. Cosmochim. Acta 37; Boelens,  Inlet,  and Paslawska,  i n bottom sediments  S.  as  1071-1076.  (1970) On the occurrence of  and i n t e r s t i t i a l  waters of  the  Southern B a l t i c Sea. Acta Geophys. P o l . 18, 277-286. Bolin,  B.  fluxes.  (1983) C, In  The  N,  P,  Major  and S c y c l e s : major r e s e r v o i r s and Biogeochemical  I n t e r a c t i o n s (eds. B. B o l i n , and R.B. 350  Cycles  and  their  Cook), pp 41-61. SCOPE  21 . Bostrom, a  K.,  Lysen, L., and Moore, C.  source of a u t h i g e n i c matter  Geol. 23,  (1978) B i o l o g i c a l matter as  in pelagic  sediments.  Chem.  11-20.  Boulegue, J . (1982) Trace metals i n anoxic environments.'In metals i n seawater. J.D. Boulegue,  (eds. C.S.  Burton, and E.D.  Wong, E. Boyle, K.W.  Trace  Bruland,  Goldberg) pp 563-578. Plenum P r e s s .  J . , and Michard, G.  (1974) I n t e r a c t i o n entre l e systeme  s u l f u r e - p o l y s u l f u r e et l a matiere organique dans l e s m i l i e u x r e d u c t e u r s . C_^ Boulegue,  J.,  Acad. Sc. P a r i s 279D, 13-15.  Lord,  C.J.  I l l , and Church, T.M.  s p e c i a t i o n and a s s o c i a t e d t r a c e metals water of Great Marsh, Delaware.  (Fe,  (1982) S u l f u r  Cu)  i n the pore  Geochim. Cosmochim. Acta 46,  453-464. Bowen,  H.J.M.  (1979)  Environmental Chemistry of the  Elements.  Academic. 333p. Boyd,  S.A., spectra  Sommers,  L.E.,  and Nelson,  of sewage sludge f r a c t i o n s :  b i n d i n g s i t e . S o i l S c i . Soc• Am. Boyd,  S.A., The  electron  spin  of  Evidence f o r an  and West, D.X.  c o p p e r ( l l ) binding  resonance study of a  by  amide  humic  (1981a)  acid:  copper(II)-humic  complex  and some adducts with n i t r o g e n  Soc. Am.  J . 45, 745-749.  351  (1979) I n f r a r e d  J . 43, 893-899.  Sommers, L.E., Nelson, D.W.,  mechanism  D.W.  donors.  Soil  An acid  Sci.  Boyd,  S.A., and  Sommers,  L.E., and Nelson, D.W.  i r o n ( I I I ) complexation by the c a r b o x y l a t e group of humic  a c i d . S o i l S c i . Soc. Am. Boyle,  (1981b) C o p p e r ( l l )  E.A.,  North  and Keigwin,  Atlantic  the  L.D.  1241-1242.  (1982) Deep c i r c u l a t i o n of the  over the l a s t  evidence. Science 218, Breger, I.A.  J . 45,  200,000  years:  Geochemical  784-787.  (i960) D i a g e n e s i s of m e t a b o l i t e s and a d i s c u s s i o n of  o r i g i n of petroleum hydrocarbons.  Geochim.  Cosmochim.  Acta 19, 297-308. Bremner,  J.M.,  matter:  and II.  Lees,  The  (1949) S t u d i e s of  p a r t i c u l a t e phases.  f l u x between d i s s o l v e d  In The Black Sea - Geology,  and B i o l o g y (eds. E.T. Degens, and D.A. 20,  Brongersma-Sanders,  by  (1974) D i s t r i b u t i o n of some t r a c e  i n Black Sea and t h e i r  Geol., Mem.  organic  A g r i c . S c i . 39, 274-279.  and Spencer, D.W.  elements  soil  e x t r a c t i o n of o r g a n i c matter from s o i l  n e u t r a l reagents. Brewer, P.G.,  H.  Ross), Am.  and  Chemistry, Ass. Pet.  137-143. M.  s u p p l i e d by normal  (1965)  Metals  seawater.  in  the  Kupferschiefer  Geologische Rundschau 55,  365-  375. Brongersma-Sanders, (1980)  African  m o r t a l i t y . Mar. R.R.,  Stephan, K.M.;  Distribution  south-west  Brooks,  M.;  of  minor  Kwee, T.G.; elements  s h e l f with notes on  and Debrun, M.  in cores  from  plankton  and  the fish  G e o l . 37, 91-132.  Presley,  B.J.,  and Kaplan, 352  I.R.  (1968)  Trace  elements  in  the i n t e r s t i t i a l waters of  marine  sediments.  Geochim. Cosmschim. Acta 32, 397-414. Brumsack, from  H.-J.  (1980)  Geochemistry of Cretaceous black shales  the A t l a n t i c Ocean (DSDP 11,  14,  36 and  11). Chem.  G e o l . 31, 1-25. Brumsack,  H.-J.,  trace-metal  and G i e s k e s ,  J.M.  (1983) I n t e r s t i t i a l  water  c h e m i s t r y of laminated sediments from the  Gulf  of C a l i f o r n i a , Mexico. Mar. Chem. 14, 89-106. Busby,  W.F., and Benson, A.A. (1973) S u l f o n i c a c i d metabolism i n  the diatom N a v i c u l a p e l l i c u l o s a . Plant and C e l l P h y s i o l . 14, 1123-1132. Calvert,  S.E.  shore  (1976)  sediments.  The mineralogy and geochemistry of In  Chemical  Oceanography  near-  Vol.6,  2nd  e d i t i o n , pp 187-280. Academic. Calvert,  S.E.,  and P r i c e ,  N.B.  (1970) Minor metal c o n t e n t s of  recent o r g a n i c - r i c h sediments o f f South West A f r i c a . 227, Calvert,  Nature  593-595. S.E.,  and M o r r i s ,  R.J.  (1977) Geochemical s t u d i e s of  o r g a n i c - r i c h sediments from the Namibian  shelf.  organic  Discovery  associations.  In  A Voyage of  I I . Metal(ed. M.  A n g e l ) , pp 667-680. Pergamon. Calvert,  S.E.,  and P r i c e ,  ferromanganese  nodules  N.B. (1977) Geochemical v a r i a t i o n i n and a s s o c i a t e d sediments  P a c i f i c Ocean. Mar. Chem. 5, 43-74.  353  from  the  Calvert,  S.E.,  and P r i c e ,  s h e l f sediments.  N.B.  (1983) Geochemistry of Namibian  In C o a s t a l Upwelling  (ed.  E. Suess and J .  T h i e d e ) , pp 337-376. Plenum. Calvert,  S.E.,  metals  Mukherjee,  S.,  and M o r r i s ,  i n humic and f u l v i c a c i d s from  sediments. Oceanol. Acta, 8, Campaigne,  E.  R.J.  (1985) Trace  modern  organic-rich  167-173.  (1961) A d d i t i o n of t h i o l s or t^S to c a r b o n y l com-  pounds.  In Organic S u l f u r Compounds, J_ (ed. N. Kharasch) pp  134-145.  Pergamon.  Campbell,  J.A., and Yeats, P.A.  northwest A t l a n t i c Ocean.  (1981) D i s s o l v e d chromium i n the Earth Plant.  S c i . L e t t . 53, 427-  433. Carpenter,  R.,  and Beasley, T.M.  (1981) Plutonium and americium  in anoxic marine sediments: evidence a g a i n s t Geochim. Cosmochim. Acta 45, Casagrande, (1977) Swamp  D.J., Sulfur and  Siefert, in  Casagrande,  1917-1930.  K., B e r s c h i n s k i , C ,  peat-forming systems of  F l o r i d a Everglades:  Geochim. Cosmochim. Acta 41, D.J.,  and Ng,  remobilization.  and Sutton, N. the  o r i g i n of s u l f u r  K.  2  L.H.,  598-599.  D.J., Idowie, G., F r i e d a n , A., R i c k e r t , P.,  (1979) H S  incorporation  Drummond,  coal.  L. (1979) I n c o r p o r a t i o n of elemental  in coal precursors,  organic sulphur i n c o a l . Nature 282, Chan,  in  161-167.  sulphur i n c o a l as organic s u l p h u r . Nature 282, Casagrande,  Okefenokee  D., Edmond J.M., 354  Siefert,  o r i g i n s of  599-600. Grant, B. (1977) On the  barium data from the A t l a n t i c GEOSECS  Expedition.  Deep-Sea  Res. 24, 613-649. Chen,  K.Y.,  and  Morris,  aqueous s u l f i d e by 0 Chen,  K.Y.,  J.C.  2 >  (1972) K i n e t i c s of o x i d a t i o n of  Env. S c i . & Tech. 6, 529-537.  and Gupta, S.K. (1973) Formation of p o l y s u l f i d e s i n  aqueous s o l u t i o n s . E n v i r o n . l e t t e r s 4, 187-200. Chester, R., and Hughes, M.J. (1967) A chemical technique f o r the separation and  of ferro-manganese  minerals,  adsorbed t r a c e elements from p e l a g i c  carbonate m i n e r a l s sediments.  Chem.  G e o l . 249-262. Clapp,  C.H.  (1913)  Vancouver Cline,  of V i c t o r i a and Saanich  (1969) Spectrophotometrie d e t e r m i n a t i o n of hydrogen  sulfide  i n n a t u r a l waters. L i m n o l . Oceanogr. R.,  Lyons,  map-area,  I s l a n d G e o l . Surv. Canada. Mem. 36.  J.D.  Contreras,  Geology  Fogg,  W.B.  marine  14, 454-458.  T.R., Chasteen, N.D., Gaudette, H.E., and  (1978) Molybdenum i n the pore waters of anoxic  sediments  by  electron  paramagnetic  resonance  spectroscopy. Mar. Chem. 6, 365-373. Cooper,  B.S.,  and H a r r i s ,  R.C.  (1974) Heavy metals i n organic  phases of r i v e r and e s t u a r i n e sediment.  Mar.  Pollut.  Bull.  5, 24-26. Cranston,  R.E.,  chromium  and  Murray,  J.W.  (1978) The d i s t r i b u t i o n  s p e c i e s i n n a t u r a l waters.  275-282.  355  Anal.  Chim.  of  Acta 99,  Cronin,  J.R.,  and M o r r i s ,  R.J.  material  from diatom d e b r i s .  Suess and  J . Thiede),  Cuhel, R.L.,  T a y l o r , CD.,  (1983) Rapid formation In C o a s t a l Upwellinq  and  Jannasch, H.W.  lism,  protein  synthesis,  and  sulfur  growth  of  T a y l o r CD.,  and  (1982) A s s i m i l a t o r y  microorganisms:  for the a p p l i c a t i o n of s u l f a t e i n c o r p o r a t i o n a measurement of n a t u r a l p o p u l a t i o n  unperturbed  8-13.  Jannasch, H.W.  metabolism i n marine  metabo-  Pseudomonas  Alteromonas l u t e o v i o l a c e u s d u r i n g  batch growth. Arch. M i c r o b i o l . 130, R.L.,  E.  (1981) A s s i m i l a t o r y  metabolism i n marine microorganisms: S u l f u r  Cuhel,  (ed.  pp 485-496. Plenum.  sulfur  halodurans and  of humic  Considerations into protein  protein synthesis.  as  Appl.  E n v i r o n . M i c r o b i o l . 43,160-168. Cuhel,  R.L.,  and  short  and Waterbury, J.B.  (1984) Biochemical composition  term n u t r i e n t i n c o r p o r a t i o n p a t t e r n s  i n an u n i c e l -  l u l a r marine cyanobacterium Synechococcus (WH7803). Oceanoqr. 29, Curtis,  CD.  370-374.  (1964) The  i n t o sediments and  i n c o r p o r a t i o n of s o l u b l e organic  i t s e f f e c t on trace-element  In Advances in Organic Geochemistry M.C Deer,  Howie, R.A.,  and  G.D.  Zussman, J . (1966) An  to the Rock-Forming M i n e r a l s . Degens,  (eds.  E.T.  (1970) Molecular  matter  assemblages. Hobson,  L o u i s ) , I n t e r n . Ser. Monograph E a r t h S c i . 24,  W.A.,  Limnol.  and  1-14.  Introduction  Longman. 528p.  nature of nitrogenous compounds i n  356  sea  water and recent marine  N a t u r a l Water (ed. I n s t . Mar. DeGroot,  Ems  Hood),  S c i . , occas. pub.  A.J.  river  D.W.  sediments.  In Organic Matter i n  pp 77-105.  Univ.  Alaska,  no1.  (1973) Occurrence and behavior of heavy metals i n  deltas,  Rivers.  with s p e c i a l r e f e r e n c e to the Rhine and  In North Sea Science (ed.  E.D.  the  Goldberg),  pp  308-325. MIT P r e s s . Dehairs,  F.,  Chesselet,  suspended  R.,  and  Jedwab,  J.  (1980) D i s c r e t e  p a r t i c l e s of b a r i t e and the barium c y c l e s i n  the  open ocean. E a r t h P l a n e t . S c i . L e t t . 49, 528-550. Demaison, oil  G.J.,  and Moore,  G.T.  source bed g e n e s i s .  Am.  (1980) Anoxic environments Ass. Pet. G e o l . B u l l . 64,  and 1179-  1209. Demaison, G.J., Hoick A . J . J . , Jones, R.W., Predictive  source  petroleum American  and Moore, G.T.  bed s t r a t i g r a p h y :  occurrence. continental  North  A guide  Sea basin and  margin.  In  11—  to  (1984) regional  eastern  World  North  Petroleum  Congress Proceedings. Vol.2, pp 17-30. Elderfield,  H.  (1970) Chromium s p e c i e s i n seawater. E a r t h P l a n e t .  S c i . L e t . 9, 10-16. Elderfield,  H.  (1981) M e t a l - o r g a n i c a s s o c i a t i o n s i n i n t e r s t i t i a l  waters of Narragansett Bay  sediments. Am.  J . S c i . 281 ,  1184—  1 196. Elderfield,  H.,  pollution  and Hepworth A.  i n e s t u a r i e s . Mar. 357  (1975) D i a g e n e s i s ,  metals and  P o l l u t . B u l l . 6, 85-87.  Elderfield,  H.,  Truesdale,  McCaffrey, V.W.  R.,  Luedtke N.,  Bender,  M.,  and  (1981) Chemical d i a g e n e s i s i n Narragansett  Bay sediments. Am. J . S c i . 281, 1021-1055. Emerson,  S., Cranston, R.E., and L i s s , P.S. (1979) Redox s p e c i e s  in a reducing f j o r d : e q u i l i b r i u m and k i n e t i c  considerations.  Deep-Sea Res., 26A, 859-878. Emerson,  S.,  trace  Jacobs,  L.,  and Tebo, B. (1982) The behaviour of  metals i n marine anoxic waters:  oxygen-hydrogen Seawater. (eds.  sulphide CS.  interface.  Wong ,  E.  S o l u b i l i t i e s a t the In Trace  Boyle, K.W.  Metals  In  Bruland, J.D.  Burton, and E.D. Goldberg) pp. 570-608. Plenum. Emery,  K.O.,  and R i t t e n b e r g ,  California  basin  S.C  (1952) E a r l y d i a g e n e s i s  sediments i n r e l a t i o n  to o r i g i n  of  of o i l .  B u l l . Am. Ass. P e t . Geol. 36, 735-806. Environment  Canada (1984) Surface water data,  B r i t i s h Columbia,  1983. Water Survey of Canada. Environment Canada  (1985) Surface water data,  British  Columbia,  1984. Water Survey of Canada. Fairbrother,  F.  (1947) Colour of i o d i n e s o l u t i o n s .  Nature 160,  87. Fawcett,  D.M.,  and  Kirkwood,  a n t i t h y r o i d a c t i o n of i o d i d e inhibitors. Fawcett,  D.M.,  S.  (1953a)  The  mechanism  of  i o n and the "aromatic" t h y r o i d  J_^ B i o l . Chem. 204, 787-796. and  Kirkwood,  358  S.  (1953b)  The  synthesis  of  organically  bound  iodine  thyroid tissue.  by  cell-free  preparations  of  B i o l . Chem. 205, 795-802.  F i s c h e r , K., Dymond, J . , L y l e , M., Soutar, A., and Rau, S. (1986) The  benthic  c y c l e of copper:  experiments  in  Evidence from sediment  the eastern t r o p i c a l North  Pacific  trap Ocean.  Geochim. Cosmochim. Acta 50, 1535-1544. Flynn,  W.W.  (1968) The d e t e r m i n a t i o n of low l e v e l s of polonium-  210 i n environmental m a t e r i a l s .  Anal.  Chim.  A c t a 43, 221-  227. Francavilla, the  electron  vanadyl Fresnel,  J . , and Chasteen, N.D. (1975) Hydroxide e f f e c t s on paramagnetic  resonance spectrum  of  aqueous  (VI) i o n . Inorq. Chem. 14, 2860-2862.  J . , Galle,  micro-analyse chromophytes  P., des  and G a y r a l , crystaux  unicellulaires  P. (1979) R e s u l t a t de l a vacuolaires  marines:  chez  deux  Exanthemachrysi s  g a y r a l i a e , Pavlova sp. (Prymnesiophycees, P a v l o v a c e e s ) . C.R. Acad. S c i . P a r i s 288, 823-825. Gadel,  F. (1979) Geochimie  superficiels.  In  des composes humiques dans l e s depots  Biogeochimie  1 " i n t e r f a c e eau-sediment  marin,  de l a matiere pp 45-60.  organique  a  C o l l o q u e i n t . du  CNRS, no 293. 2+ Gamble,  D.S.,  S c h n i t z e r , M., and Hoffman, I . (1970) Cu  a c i d c h e l a t i o n e q u i l i b r i u m i n 0.1 M KC1 at 25.0°C.  -fulvic Can. J .  Chem. 48, 3197-3204. Gardner,  L.R.  (1974)  Organic 359  versus  inorganic  trace  metal  complexes  in  sulfidic  marine  waters  - some  speculative  c a l c u l a t i o n s based on a v a i l a b l e s t a b i l i t y c o n s t a n t . Geochim. Cosmochim. Acta Gardner,  W.D.  Gardner,  of sediment t r a p s . J ^ Mar.  4 1 - 5 2 .  W.D.,  the  1 2 9 7 - 1 3 0 2 .  F i e l d assessment  (1980)  3 8 ,  Res.  3 8 ,  Hinga, K.R., and Marra, J .  d e g r a d a t i o n of b i o g e n i c m a t e r i a l i n the deep ocean with  i m p l i c a t i o n s on accuracy of sediment t r a p 4 1 ,  Res.  Garrels,  R.M.,  Goldberg,  and  and  Perry J r . ,  oxygen  E.A.  E.D.  Mar.  1 7 ,  Goldberg, E.D.,  C y c l i n g of carbon,  3 0 3 - 3 3 6 .  and  incorporation  Sea  1 7 8 - 1 8 2 .  and A r r h e n i u s , G.O.S.  M.B.,  In The  Wiley.  (1958)  Chemistry of P a c i f i c  p e l a g i c sediments. Geochim. Cosmochim. Acta Goldhaber,  J_^ Mar.  Determination of opal i n marine sediments.  (1958)  Res.  ( 1 9 7 4 )  through g e o l o g i c a l times.  (ed. E.D. Goldberg), pp  Vol.5  fluxes.  1 9 5 - 2 1 4 .  sulfur,  LK  O b s e r v a t i o n s on  ( 1 9 8 3 )  Kaplan I.R.  ( 1 9 8 0 )  1 3 ,  1 5 3 - 2 1 2 .  Mechanism of  sulphur  and isotope f r a c t i o n a t i o n d u r i n g e a r l y diage-  n e s i s i n sediments of the Gulf of C a l i f o r n i a .  Mar. Chem. 9 ,  9 5 - 1 4 3 .  Goldschmidt, V.M. Gozlan,  R.S.  (1954)  (1968)  Geochemistry. Clarendon.  I s o l a t i o n of i o d i n e - p r o d u c i n g b a c t e r i a  from  a q u a r i a . Antonie van Leeuwenhoek 3 4 , 2 2 6 . Gozlan,  R.S.,  and  Margalith  P.  360  ( 1 9 7 3 )  Iodide o x i d a t i o n by  a  marine bacterium. Greenslate, and  Appl. Bact. 36, 407-417.  J.L., F r a z e r , J.Z., and A r r h e n i u s , G.  deposition  seabed.  In  of  Papers  selected  transition  on  the  origin  in  the  Pacific  (1973). O r i g i n  elements  and  in  the  distribution  manganese  nodules  exploration  (ed. M. Morgenstein), pp 45-68. Honolulu, Hawaii  Grill,  E.V.  and  prospects  of for  (1982) K i n e t i c and thermodynamic f a c t o r s c o n t r o l l i n g  manganese  concentrations  in  oceanic  waters.  Geochim.  Cosmochim. Acta 46, 2435-2446. Gross,  M.G.  (1967)  diatomaceous  Concentrations  sediments of  M.G.,  Gucluer,  S.M.,  Gucluer,  Ass. Adv.  Creager,  (1963) Varved marine sediments 141,  minor  a stagnant f j o r d .  (ed. L a u f f G.M.), pp 273-282. Am. Gross,  of  J.S.,  elements In  in  Estuaries  S c i . Pub. and Dawson,  i n a stagnant f j o r d .  W.A.  Science  918-919. S.M.,  and Gross, M.G.  (1964) Recent marine sediments i n  Saanich I n l e t , a stagnant marine b a s i n . Limnol• Oceanogr. 9, 359-376. Guthrie, total  T.F.,  and Lowe, L.E.  (1984) A comparison  sulphur a n a l y s i s of t r e e f o l i a g e .  Can.  of methods f o r J.  For. Res.  14,470-473. Hallberg,  R.O.,  chelation  Bubela,  B.,  i n sedimentary  and  Ferguson,  systems.  J.  (1979)  Geomicrobiol.  J . 2,  Metal 99-  113. H a r r i s o n , A.G.,  and Thode, H.G.  (1958) Mechanism of the b a c t e r i a l 361  reduction  of sulphate from i s o t o p e  fractionation  studies.  Trans. Farad. Soc. 54, 84-92. Harrison,  P.G.,  eelgrass  and Mann,  (Zostera  fragmentation,  K.H.  marina  (1975) D e t r i t u s formation from  L.):  leaching,  The  relative  and decay.  effects  Limnol.  of  Oceanoqr.  20,924-934. Harrison,  P.G.,  spectrum  Water,  R.E., and T a y l o r F.J.R. (1980) A broad  artificial  seawater medium f o r c o a s t a l  and open  ocean phytoplankton. J;_ P h y c o l . 16, 28-35. Harvey,  G.R.  bromine Harvey,  (1980)  A  study of the chemistry  of  iodine  and  i n marine sediments. Mar. Chem. 8, 327-332.  G.R.,  and Boran,  substances Sediment,  D.A.  i n seawater.  (1985) Geochemistry  In  and Water (eds.  Humic  G.R.  Substances  of  humic  in  Soil,  Aiken, D.M. McKnight, R.L.  Wershaw, and P. MacCarthy), pp 233-248. Wiley. Hatcher,  P.G.,  Structural  Breger,  I.A., and M a t t i n g l y ,  c h a r a c t e r i s t i c s of f u l v i c  s h e l f sediments. Nature 285,  M.A.  (1980)  a c i d s from c o n t i n e n t a l  560-562.  Hayes, M.H.B. (1985) E x t r a c t i o n of humic substances from s o i l . In Humic Substances i n S o i l , Aiken,  D.M.  McKnight,  Sediment,  and Water  (eds. G.R.  R.L. Wershaw, and P. MacCarthy), pp  329-362. Wiley. Hayes,  M.H.B.,  organic  and S w i f t ,  colloids.  R.S.  (1978) The chemistry of  In The Chemistry of  362  Soil  soil  Constituents  (eds. D.J. Greenland, and M.H.B. Hayes), pp 179-230. Wiley. Hedges, J . I . , and Parker, P.L. (1976) Land-derived organic matter in  surface  sediments  from the Gulf  of  Mexico.  Geochim.  Cosmochim. Acta 40, 1019-1029. Herlinveaux,  R.H.  Vancouver  (1962)  Oceanography  of  Saanich  Inlet  in  I s l a n d , B r i t i s h Columbia. J_;_ F i s h . Res. Bd. Canada  19, 1-37. H e r l i n v e a u x , R.H. (1968) Features of water movement over the s i l l of  Saanich I n l e t .  J u n e - J u l y 1966.  Fish.Res.  Bd.  Canada.  Tech. Rep, no. 99 H e r l i n v e a u x , R.H. (1972) Oceanographic 9 May - 2 J u l y  1966.  Fish.  f e a t u r e s of Saanich I n l e t .  Res. Bd. Canada. Tech. Rep, no.  300 H i l d e b r a n d , J.H., B e n e s i , H.A., and Mower, L.M. (1950) S o l u b i l i t y of  iodine in ethyl a l c o h o l ,  xylene,  2,2-dimethyl  butane,  ethyl  ether,  mes'itylene,  p-  cyclohexane and p e r f l u o r o - n -  heptane. Am. Chem. Soc. J . 72, 1017-1020. Hirata, in Cu,  S.  (1985) Phosphorus  c o a s t a l sediments. Zn,  An i n v e s t i g a t i o n of complexes  of  P,  Fe, Mn, N i , Co, and T i by I . C P . with Sephadex g e l  chromatography. H i r s t , D.M.  and metals bound to organic matter  Mar. Chem. 16, 23-46.  (1962a) The geochemistry of modern sediments from the  Gulf of P a r i a - I .  The r e l a t i o n s h i p between the  and the d i s t r i b u t i o n of major elements. Acta 26, 309-334. 363  mineralogy  Geochim. Cosmochim.  H i r s t , D.M. Gulf  (1962b) The geochemistry of P a r i a - I I .  elements. Hobson,  L.A.  rates  (1981) Seasonal v a r i a t i o n  of phytoplankton  S.  (1982)  lithogenic 218,  from the  The l o c a t i o n and d i s t r i b u t i o n of t r a c e  Geochim. Cosmochim. Acta 26,  B r i t i s h Columbia. Honjo,  of modern sediments  1147-1187.  i n maximum p h o t o s y n t h e t i c  i n Saanich I n l e t ,  Vancou