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Distribution and taxonomy of planktonic marine diatoms in the Strait of Georgia, B.C. Shim, Jae Hyung 1976

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DISTRIBUTION AND TAXONOMY OF PLANKTONIC MARINE DIATOMS IN THE STRAIT OF GEORGIA, B. C. BY JAE H YUNG SHIH B . 5 c , Seoul N a t i o n a l U n i v e r s i t y , 1963 M.Sc, Seoul N a t i o n a l U n i v e r s i t y , 196b THESIS SUBMITTED IN PARTIAL FULFILHENi THE REQUIREMENTS FOB THE DEGREE OF DOCTOH OF PHILOSOPHY i n the Department of Botany Me accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA September 1976 © Jae Hyung Shim In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f Botany The U n i v e r s i t y o f B r i t i s h Columbia Vancouver 8, Canada October 3, 1976 ABSTRACT The primary o b j e c t i v e s of t h i s study were the i d e n t i f i c a t i o n and measurement of diatom genera and s p e c i e s making up the diatom communities i n the plankton of the S t r a i t of Georgia/Juan de Fuca S t r a i t system, and f a c t o r s i n f l u e n c i n g t h e i r d i s t r i b u t i o n a l ecology. The p l a n k t o n i c diatom communities at depths of one, 25, 50, and 75 meters i n the area were s t u d i e d and measured over a f i f t e e n month p e r i o d . Measurements of environmental f a c t o r s i n c l u d e d temperature , s a l i n i t y and a l g a l n u t r i e n t s such as phosphate, s i l i c a t e , n i t r a t e , n i t r i t e and ammonia. Attempts were made to e s t a b l i s h r e l a t i o n s h i p s between environmental f a c t o r s measured and marine p l a n k t o n i c diatoms through the use of m u l t i p l e r e g r e s s i o n a n a l y s e s . The r e s u l t s i n d i c a t e t hat the t o t a l abundances of diatom communities and the s p e c i e s p o p u l a t i o n changes were s t r o n g l y c o r r e l a t e d with season and l o c a t i o n parameters (in which the exact r e g u l a t i n g parameters are unknown) as well as s p e c i f i c n u t r i e n t c o n c e n t r a t i o n s and hydrographic f a c t o r s . Major i n f l u e n c e s on p o p u l a t i o n d i s t r i b u t i o n s v a r i e d with the p r i n c i p a l s p e c i e s r e s p o n s i b l e f o r the observed s p e c i e s s u c c e s s i o n s . Two d i s t i n c t d i s t r i b u t i o n a l p a t t e r n s i n t o t a l diatom s t a n d i n g crop were observed i n the study area. Maximum sta n d i n g c r o p s observed d u r i n g s p r i n g and/or summer did not u s u a l l y r e s u l t i n the d e p l e t i o n of c r i t i c a l n u t r i e n t s (such as s i l i c a t e , n i t r a t e ) to l e v e l s which might be growth l i m i t i n g . In a few i n s t a n c e s phosphorus c o n c e n t r a t i o n was undetectable. On a s m a l l s c a l e , the d i s t r i b u t i o n of t o t a l diatom s t a L d i n q crop was s i g n i f i c a n t l y c o r r e l a t e d with both s e a s o n / l o c a t i o a f a c t o r s and with hydrographic parameters. V e r t i c a l s t r a t i f i c a t i o n of diatoms was observed o n l y i n the presence of the t h e r m o c l i n e / h a l o c l i n e i n the water column. The d i s t r i b u t i o n of r e c u r r e n t groups of diatoms was r e l a t e d p r i m a r i l y to the p h y s i c a l c o n d i t i o n s . Within the study area t h e r e was some se a s o n a l c o n s i s t e n c y i n the composition of the s p e c i e s groups. There were r a d i c a l changes i n community s t r u c t u r e with d i f f e r e n t seasons, as was expected. Two hundred and nineteen taxa have been i d e n t i f i e d as a r e s u l t s of l i g h t and scanning e l e c t r o n microscope o b s e r v a t i o n s . These taxa are a t t r i b u t e d to 66 genera within 16 f a m i l i e s . Of the t o t a l number of taxa three appear to be new s p e c i e s and f i v e are new i n f r a s p e c i f i c taxa. S i x t y - e i g h t taxa are uew r e c o r d s f o r western Canada. Some changes i n the p r e v i o u s c l a s s i f i c a t i o n system were made usinq new i n f o r m a t i o n wnich aas been accumulated through b e t t e r t e c h n i c a l f a c i l i t i e s , e s p e c i a l l y through the scanning e l e c t r o n microscope. The diatom c l a s s i f i c a t i o n system used here was based on the present s t a t e of knowledege of diatoms and the author's own o b s e r v a t i o n s . i v TABLE OF CONTENTS ABSTB ACT ............. i i TABLE OF CONTENTS i v LIST OF TABLES . ... v i LIST OF FIGURES . v i i ACKNOWLEDGEMENT v i i i INTRODUCTION 1 Purposes 1 D e s c r i p t i o n of the Study Area .. 2 Background of the Study 4 MATERIALS AND METHODS 10 C o l l e c t i o n and P r e s e r v a t i o n •••• 10 The Invert e d Microscope Method of Enumeration ... 10 Q u a l i t a t i v e Species Data 15 Analyses of P h y s i c a l and Chemical Parameters .... 15 S t a t i s t i c a l Analyses 16 A f f i n i t y Index 17 RESULTS 19 Temperature and S a l i n i t y 19 Pl a n t N u t r i e n t s 28 Diatoms 36 Regression Analyses 54 Recurrent Species Groups Analyses ............... 72 DISCUSSION 75 The g e n e r a l Seasonal D i s t r i b u t i o n of Standing Crop 75 V e r t i c a l D i s t r i b u t i o n ........................... 80 Regression Analyses ............................. 89 Species D i s t r i b u t i o n ............................ 98 The D i s t r i b u t i o n of Recurrent Species Groups .... 104 CLASSIFICATION 107 SUMMARY AND CONCLUSIONS .............................. 114 SYSTEMATIC ACCOUNT 118 REFERENCES CITED 191 APPENDIX 213 PLATES I-XXV 222 v i LIST OF TABLES TABLE PAGE I Dates and numbers of c r u i s e s to the S t r a i t of G e o r g i a / Juan de Fuca S t r a i t system during t i s study, May 1972-July 1973 . .... 1 1 I I V a r i a b i l i t y of c e l l counts i n four r e p l i c a t e s ........ 20 I I I Phosphorus c o n c e n t r a t i o n s (ug-at/1) during May 19 72-J u l y 1973 .... 29 IV N i t r a t e c o n c e n t r a t i o n s (ug-at/1) during Hay 1972-July 1973 30 V N i t r i t e c o n c e n t r a t i o n s (ug-at/1) during May 1972-July 1973 31 VI Ammonia c o n c e n t r a t i o n s (ug-at/1) during May 1972-July 1973 32 VII S i l i c a t e c o n c e n t r a t i o n s (ug-at/1) during May 1972-J u l y 1973 ... .... 33 VIII The abundance and h a b i t a t s of diatom s p e c i e s i a the S t r a i t of Georgia/ Juan de Fuca S t r a i t system ....... 44 IX R e l a t i o n s h i p between t o t a l standing crop and environmental parameters 56 X fielationship between t o t a l standing crop and environmental parameters i n each month during May 1972-July 1973 57 XI R e l a t i o n s h i p between t o t a l s t a n d i n g crop and environmental parameters at each s t a t i o n ............ 5 9 XII R e l a t i o n s h i p between p l a n k t o n i c diatom species and environmental parameters 63 XIII Species composition of r e c u r r e n t groups ( s p e c i e s l i s t e d i n order of descending abundance) 73 LIST OF FIGURES IJGUJE PAGE 1. The S t r a i t of Georgia/Juan de Fuca S t r a i t system, showing f i v e s t a t i o n p o s i t i o n s ........................ 3 2. Seasonal c y c l e of temperature and s a l i n i t y at s t a t i o n 1. .......... 22 3. Seasonal c y c l e of temperature and s a l i n i t y at s t a t i o n 2 23 4. Seasonal c y c l e of temperature and s a l i n i t y at s t a t i o n 3 24 5. Seasonal c y c l e of temperature and s a l i n i t y a t s t a t i o n 4 25 6. Seasonal c y c l e of temperature and s a l i n i t y a t s t a t i o n 5 26 7. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 1 37 8. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 2 38 9. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 3 39 10. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 4 40 11. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 5 41 12. T o t a l d a i l y and monthly mean r a d i a t i o n r e c e i v e d on a h o r i z o n t a l s u r f a c e at Nanaimo (from Department of Environment Records, 1972, 1973) 83 13. T o t a l d a i l y and monthly mean r a d i a t i o n r e c e i v e d on a h o r i z o n t a l s u r f a c e at The U n i v e r s i t y of B r i t i s h Columbia(from Department of Environment Records, 1972, 1973) 84 v i i i ACKNOWLEDGEMENTS I am e s p e c i a l l y g r a t e f u l t o Dr. F. J . H. T a y l o r , my resear c h s u p e r v i s o r , f o r h i s help t o develop-' the i d e a s during t h i s study and f o r many i n v a l u a b l e c r i t i c i s m s of t h i s t h e s i s . I wish t o express my s i n c e r e thanks to Drs. T. E. Parsons, R. W. B u r l i n g , and G. C. Hughes who served on the t h e s i s committee, as well as to Dr. J. C. Lewin who served as the e x t e r n a l examiner. They read the t h e s i s and provided v a l u a b l e suggestions f o r i t s improvement. The h e l p f u l advice given by Drs. G. L. P i c k a r d and R. F. Scagel i s a l s o acknowledged. S p e c i a l thanks go to Dr. S. Borden and Mrs. D. L a u r i e n t e , who developed the computer program used i n t h i s study, to Mrs, M. S l a t e r , who gave me t e c h n i c a l a s s i s t a n c e on scanning e l e c t r o n microscopy, and to Mr. I. S l a t e r who read the manuscript of the t h e s i s . I t i s my plaesure to thank the o f f i c e r s and crew of the C. S. S. Vector f o r t h e i r v aluable a s s i s t a n c e and c o r p o r a t i o n . F i n a l l y , I should l i k e thank my wife, without whose patience and encouragement the study would not have been p o s s i b l e . 1 INTRODUCTION Purposes T h i s program was undertaken p r i m a r i l y t o f i l l a need i n the study of diatoms i n B. C. c o a s t a l waters. Although the i d e n t i f i c a t i o n of marine diatoms i n the B. C. c o a s t a l waters was s t a r t e d more than a century ago (Lord, 1866), very l i t t l e has been done that s p e c i f i c a l l y r e l a t e s t o t h i s area, and t h e r e i s a need f o r a c r i t i c a l study of s p e c i e s u s u a l l y i d e n t i f i e d under r o u t i n e c o n d i t i o n s from manuals such as t h a t of Cupp(1943). Secondly, more d e t a i l e d s t u d i e s of p l a n k t o n i c diatom p o p u l a t i o n s and s p e c i e s d i s t r i b u t i o n are needed t h a t i n c l u d e r e f e r e n c e to environmental f a c t o r s , even though there have been some attempts made to study the ecology of phytoplankton as a whole i n the area. The approach used i n t h i s study was t r a d i t i o n a l ; i . e . the e s t i m a t i o n of p l a n k t o n i c diatom s p e c i e s numbers a t v a r i o u s depths and l o c a t i o n s i n the S t r a i t of Georgia and a s s o c i a t e d c o a s t a l waters. Measurements of p h y s i c a l and chemical parameters that c o u l d a f f e c t the diatom p o p u l a t i o n s were made c o n c u r r e n t l y to permit some i n t e r p r e t a t i o n of t h e i r p o s s i b l e r e l a t i v e importance i n determining s p a t i o t e m p o r a l d i s t r i b u t i o n s . While the l i m i t a t i o n s of t h i s type of approach are e v i d e n t , i t forms a v a l u a b l e c o u n t e r p a r t to l e s s d i s c r i m i n a t o r y s t u d i e s of phytoplankton ecology i n the f i e l d , and more h i g h l y s p e c i f i c , c o n t r o l l e d l a b o r a t o r y s t u d i e s . 2 D e s c r i p t i o n of the Stud^ Area The S t r a i t of Georgia i s the i n s i d e passage between Vancouver I s l a n d and the B r i t i s h Columbia mainland. F i g u r e 1 shows the southern p a r t of the S t r a i t o f Georgia and Juan de Fuca S t r a i t area where t h i s study has been c a r r i e d out. The northern entrance to the S t r a i t of Georgia c o n s i s t s of three i n t e r c o n n e c t i n g channels. The southern entrance a l s o c o n s i s t s of i n t e r c o n n e c t i n g channels forming the S t r a i t of Georgia/Juan de Fuca S t r a i t system. T h i s system i s approximately 480 km i n l e n g t h and up to 48 km wide (Herlinveaux and Giovando, 1969), and has an average depth of between 90 m and 180 m { T u l l y and Dodimead, 1957). The waters w i t h i n t h i s area possess d i s t i n c t i v e p h y s i c a l and chemical c h a r a c t e r i s t i c s and are d i v i s i b l e i n t o a number of domains (Hutchinson and Lucas, 1931; T u l l y and Dodimead, 1957; P i c k a r d , 1961; Herlinveaux and Giovando, 1969). Baldichuk (1957) d i v i d e d the waters of the S t r a i t o f Georgia/Juan de Fuca S t r a i t system i n t o t h r e e b a s i c water masses d i s t i n g u i s h e d v e r t i c a l l y , while Herlinveaux and Giovando i n d i c a t e d three h o r i z o n t a l domains. For Haldichuk the t h r e e were (1) the b r a c k i s h s u r f a c e water from r u n o f f i n the S t r a i t of Georgia; (2) the deep water of oceanic o r i g i n i n Juan de Fuca S t r a i t ; and (3) a mixture of both. For Herlinveaux and Giovando the southern p a r t of the S t r a i t of Georgia/Juan de Fuca S t r a i t system c o n s i s t s of a c e n t r a l domain between Nanaimo and A c t i v e Pass; a homogeneous domain between A c t i v e Pass and Haro S t r a i t ; and a c o a s t a l seaways domain i n Juan de Fuca S t r a i t . 4 On t h i s b a s i s t h a f o l l o w i n g s t a t i o n s were chosen f o r t h i s study. S t a t i o n 1 : S t r a i t of Georgia 49°17.0'N-123°50.51 19 S t a t i o n 2:Fraser River plume 4 9° 01. 3* N-123° 18. 5»W S t a t i o n 3:Boundary Pass 48° 50.1'N-122° 57.4* 8 S t a t i o n 4:Haro S t r a i t 48*29.2'N-123°9.0»a S t a t i o n 5:Juan de Fuca S t r a i t 48°15.0'N-123 642.5»H . S t a t i o n 1 i n the S t r a i t of Georgia i s l o c a t e d i n the r e l a t i v e l y homogeneous b r a c k i s h water (Waldichuk, 1957). F r a s e r R i v e r r u n o f f a f f e c t s the s t a b i l i t y of the water column i n t h i s l o c a t i o n . S t a t i o n 2 i n the F r a s e r R i v e r plume i s most h e a v i l y a f f e c t e d by t h a f r e s h water d i s c h a r g e showing very low s a l i n i t y . S t a t i o n 3 i s at the j u n c t i o n of Boundary Pass with the S t r a i t of Georgia; S t a t i o n 4 i s l o c a t e d i n Haro S t r a i t . Both S t a t i o n s 3 and 4 are l o c a t e d i n the areas of i n t e n s i v e t i d a l mixing. S t a t i o n 5 i n Juan de Fuca S t r a i t i s l o c a t e d i n the c o a s t a l seaways domain (Harlinveaux and Giovando, 1969). Background of the Study. The study o f marine diatoms began on a l a r g e s c a l e i n 1870 with the around the world voyage o f H. M. S. C ^ a l i e n g e r ^ The 5 d e t a i l e d d e s c r i p t i o n s by Castracane (1886) of the diatoms from the C h a l l e n g e r c o l l e c t i o n s form the b a s i s of tod ay*s knowledge of marine diatom taxonomy. Many subseguent e x p e d i t i o n s r a p i d l y augmented the r e s u l t s of the Challencjer e x p e d i t i o n . Notable c o n t r i b u t i o n s to the taxonomy and ecology of marine diatoms were made du r i n g the A l b a t r o s s voyages i n the P a c i f i c Ocean between 1888 and 1904 (Mann, 1907), the Norwegian North Po l a r E x p e d i t i o n i n 1893 (Gran, 1900), the German Deep Sea E x p e d i t i o n through the Southern A t l a n t i c , the Indian Ocean and A n t a r c t i c Ocean i n 1898-1899 (Karsten, 1905, 1906, 1907 ) , the B e l g i a n A n t a r c t i c E x p e d i t i o n i n 1897-1899 (Van Heurck, 1909), the German A n t a r c t i c E x p e d i t i o n i n 1938/39 (Hustedt, 1958) through the South A t l a n t i c and A n t a r c t i c Oceans, the South A f r i c a n I n t e r n a t i o n a l I n d i a n Ocean C r u i s e s i n the south-western Indian Ocean i n 1962-1963 ( T a y l o r , 1966), and the German Indian Ocean E x p e d i t i o n of the Meteor i n 1964-1965 (Simonsen, 1974). Besides the r e s u l t s of the e x p e d i t i o n s , some of the most v a l u a b l e s t u d i e s of marine diatom taxonomy have been done from the m a t e r i a l s of many sources. These are 'The t r e a t i s e on - the, Diatomaceaa (Van Heurck, 1896), Diatomees Marines de France ( P e r a g a l l o and P e r a g a l l o , 1897-19081), ik t l a s der Diatomaceenkunde (Schmidt, 1874-1959), Sj^nogsis of the N a v i c u l o i d Diatoms (Cleve, 1894-1896) , Synopsis of North American • Diatomaceae (Bayer, 1926-1927), Die K i g s e l a l g e n Peut schlands, Oes t r r e i c h und der Schweiz Ij. - l i t I I I (Hustedt, 1927-1966), Diatomeen von Schweden und Finland,, I i V (Cleve-E u l e r , 1951-1955) and 2iatomee&sch>ale.n im 6 Jl§Jli£2E§3Si^E2sKo£ischen B i l d . LZHLJL (Helmcke and Krieger, 195a-1974) . The sampling methods employed on the early expeditions were varied. Many of them depended upon nets; others on f i l t e r e d or centrifuged water samples so as to remove the organisms. Some r e l i e d for species i d e n t i f i c a t i o n either partly or e n t i r e l y on diatom frustules deposited in sediments. The l a s t i n g value of the r e s u l t s l i e s i n t h e i r contributions to diatom taxonomy and qu a l i t a t i v e features of the geographic d i s t r i b u t i o n of diatoms, as well as of the autecology of common species. In some expeditions, although individual diatom species were not considered, valuable information on the phytoplankton of the ocean i n terms of the d i s t r i b u t i o n of standing crop and re l a t i v e productivity were accumulated. Such expeditions included the German Plankton Expedition to the Humbolt Current in 1899 (Hensen, 1911) the Meteor Expedition-to the P a c i f i c i n 1925-1927 (Hentschell, 1932), the Car n § gie Exp edit i on to the P a c i f i c i n 1928-1929 (Graham, 1943), and the Norwegian Brateag Expedition i n 1947-1948 (Hasle, 1969) through the P a c i f i c Southern Ocean. Hasle also used the same materials from the Brateaa Expedition for detailed diatom studies separately. The establishment of permanent oceanographic stations during the early 1900's f a c i l i t a t e d more detailed studies of phytoplankton populations i n smaller areas. The results of these studies have contributed to the understanding of g u a l i t a t i v e and quantitative c h a r a c t e r i s t i c s of the annual cycles of 7 phytoplankton communities, i n c l u d i n g f l u c t u a t i o n s i n t o t a l s t a nding crop and p r o d u c t i v i t y , s u c c e s s i o n w i t h i n the community, and the apparent r e l a t i o n s h i p s of these to environmental c o n d i t i o n s , Most noteworthy works were s t u d i e s which have been done at the U n i v e r s i t y of Oslo on the phytoplankton i n northern European waters (Gran, 1927, 1929, 1930; Braarud, Gaarder and Grontved, 1953; Braarud, Gaarder and N o r d l i , 1 958) . S c i e n t i s t s from s e v e r a l s t a t i o n s i n the United States have a l s o i n v e s t i g a t e d the s e a s o n a l c y c l e of phytoplankton i n the Western A t l a n t i c , i n c l u d i n g the Sargasso Sea ( R i l e y , 1939, 1942, 1957; Hulber t , Ryther and G u i l l a r d , 1960), Long I s l a n d Sound ( R i l e y , 1941; Conover, 1966), and the Bay o f Fundy and the Gulf of Maine (Gran, 1933; Gran and Braarud, 1935). Holmes (1956) s t u d i e d the annual c y c l e of phytoplankton i n the Labrador Sea, and Bursa (1961) f o l l o w e d i n the A t l a n t i c r e g i o n . In the P a c i f i c r e g i o n much of the e a r l y study was done by W. E. A l l e n , who made e x t e n s i v e i n v e s t i g a t i o n s i n the C a l i f o r n i a Current ( A l l e n , 1939, 1945; Sverdrup and A l l e n , 1939) and i n the Gul f of C a l i f o r n i a ( A l l e n , 1937; G i l b e r t and A l l e n , 1943). A d d i t i o n a l s t u d i e s have been done i n t h e open North P a c i f i c and i n the Kuroshio Current (Semina, 1956; Motoda and Marumo, 1963). S t u d i e s of marine diatoms i n the S t r a i t of Georgia and neighbouring c o a s t a l waters had a l r e a d y begun i n the 1860's (Lord, 1866; Peck and Harrington, 1897). Some e a r l y s t u d i e s o f marine diatoms of the east coast area o f Vancouver I s l a n d were c a r r i e d out by B a i l e y and MacKay(1916), i n the v i c i n i t y of the 8 F r a s e r River by Lucas and Hutchinson(1927), Hutchinson(1928), i n the S t r a i t of Georgia by Hutchinson et a l . (1929), Legare (1 957) , and i n the area between Juan de Fuca S t r a i t and Puget Sound (Gran and Thompson 1930; P h i f e r , 1933, 1934 a,b; Thompson and P h i f e r , 1936). The most notable s t u d i e s of taxonomy of marine p l a n k t o n i c diatoms i n the area and North P a c i f i c c o a s t of America were made by Gran and Angst (1931) and Cupp(1943). Since then no f u r t h e r taxonomic s t u d i e s have been done. Recently, Lewin and her co-workers(Lewin and Mackas, 1972; Lewin and Hruby, 1972; Lewin, 1973; C o l l o s and Lewin, 1974, 1976; Lewin, et a l . , 1975; Lewin and Eao, 1975) have c a r r i e d out a s e r i e s of s t u d i e s on sur f - z o n e diatoms along the coast of the Olympic Penninsula, Washington. They have been devoted mainly t o s t u d i e s of the p h y s i o l o g i c a l a d a p t a t i o n of two diatoms (always dominants and extremely c o n c e n t r a t e d i n the area) to the unusual h a b i t a t , but have i n c l u d e d some environmental data as w e l l . In g e n e r a l , c o a s t a l waters and near shore environments are s t r o n g l y i n f l u e n c e d by the proximity of la n d . T h i s o c c u r s both d i r e c t l y through t e r r e s t r i a l r u n o f f and by the i n f l o w o f i n o r g a n i c and o r g a n i c n u t r i e n t s , growth f a c t o r s , and i n h i b i t o r s , and, i n d i r e c t l y , by the upwelling of the c o a s t a l waters due to l o c a l winds and c u r r e n t s . Furthermore, the l i f e c y c l e s of many n e r i t i c diatoms i n c l u d e the formation of h e a v i l y s i l i c i f i e d r e s t i n g spores under unfavorable c o n d i t i o n s (Wimpenny, 1966). These s p e c i e s depend upon the proximity of the sea f l o o r to r e t a i n the spores w i t h i n the depth range of winter t u r b u l e n c e which r e t u r n s them t o the euphotic zone. Thus, the p h y s i c a l 9 c o m p l e x i t i e s of the near-shore environment, as well as the s p e c i a l i z e d l i f e c y c l e s of n e r i t i c s p e c i e s , may g i v e the p l a n k t o n i c diatom community of c o a s t a l waters dynamic c h a r a c t e r i s t i c s and d i s t i n c t e c o l o g i c a l p a t t e r n s . 10 MATERIALS AND METHODS C o l l e c t i o n an d P r e s e r v a t i o n The diatoms c o n s i d e r e d i n t h i s study were c o l l e c t e d from 5 s t a t i o n s which were l o c a t e d i n the S t r a i t of Georgia/Juan de Fuca S t r a i t system. The c o l l e c t i o n s were made a t mare or l e s s monthly i n t e r v a l s d u r i n g 15 c r u i s e s between May 1972 and J u l y 1973 on CSS Vectors Table I g i v e s c r u i s e numbers and dates. S t a t i o n s were taken at approximately 20 mile i n t e r v a l s . At each s t a t i o n samples were c o l l e c t e d from depths of 1, 25, 50, and 75 meters, using p l a s t i c N.I.O. (National I n s t i t u t e of Oceanography) water samplers of 1200 ml c a p a c i t y with r e v e r s i n g thermometers. For the q u a n t i t a t i v e s t u d i e s of diatoms 230 ml each sample was preserved with Lugol's s o l u t i o n ( U t e r m 5 h l , 1958) which was modified by adding sodium a c e t a t e . In order to prevent o x i d a t i o n during s t o r a g e each sample c o n t a i n e r was r e s e a l e d with black e l e c t r i c i a n ' s tape and kept i n the dark. Tha remaining water was used f o r the measurement of s a l i n i t y , phosphate, s i l i c a t e , n i t r a t e , n i t r i t e and ammonia. For q u a l i t a t i v e s t u d i e s , diatoms were c o l l e c t e d by v e r t i c a l net ha u l from 7 5 m t o s u r f a c e a t each s t a t i o n . The net used f o r t h i s purpose was made of s y n t h e t i c nylon with mesh s i z e of 53um and the diameter of the net r i n g was 50 cm. N e u t r a l i z e d f o r m a l i n was added so t h a t each sample contained a f i n a l c o n c e n t r a t i o n of 5% f o r m a l i n . 11 T a b l e I . Date and numbers of c r u i s e s to the S t r a i t of G e o r g i a - J u a n de Fuca system d u r i n g t h i s study, May 1972 to J u l y 1973 C r u i s e No. Date 72/20 May 8 - 9 , 1972 72/24 June 5 - 6 , 1972 72/27 J u l y 11-12, 1972 72/32 August 16-17, 1972 72/36 September 12-13, 1972 72/39 October 10-11, 1972 72/42 .November 7-8, 1972 72/45 December 6-7, 1972 73/1 January 16-17, 1973 73/3 February 13-14, 1973 73/8 March 13-14, 1973 73/12 A p r i l 15-16, 1973 73/17 May 15-16, 1973 73/24 June 17-18, 1973 73/28 J u l y 19-20, 1973 12 The I n v e r t e d Microscope Method of JEjjuroeration Utermohl's sedimentation method (Utermohl, 19 31, 1958; Lund §i a l . , 1958) was used f o r the enumeration of the diatom s p e c i e s . The sample i n a b o t t l e was shaken thoroughly by hand i n order to loosen any organisms attached to the g l a s s and to d i s t r i b u t e them evenly throughout the water. An a l i q u o t was poured i n t o a c y l i n d r i c a l chamber of 10 ml c a p a c i t y with an i n s i d e diameter of 2 5 ma, covered and l e f t undisturbed f o r at l e a s t 12 hrs t o s e t t l e on the g l a s s bottom p l a t e . The p l a t e was 0.3 mm t h i c k and the chamber was c l o s e d by a cover p l a t e of 32 mm diameter. Depending on the t o t a l abundance of the diatoms, 5 ml, 50 ml and 100 ml chambers were a l s o used. The amount of diatoms present i n the net samples served as a quick i n d i c a t o r of the most a p p r o p r i a t e chamber to use. The success of t h i s method depends on the e f f e c t i v e n e s s of the s e t t l i n g of the suspended m a t e r i a l s . Utermo'hl (1958) objected to the use of t a l l tube chambers because more organisms may be attached to the w a l l s and elude c o u n t i n g . T h i s may be the case with some chain-forming s p e c i e s of the s e t a e - b e a r i n g genus Chaetoceros (Paasche, 1960). Otermo'hl (1931, 1958) allowed 24 hrs f o r a l l organisms to s e t t l e on the bottom. Evans(1972) allowed about one hour f o r each ml of subsample with a modified sedimentation method. Osing t h i s method i n a marine phytoplankton study, Steemann-Nielsen (1933) claimed t h a t 24 hours was ample time f o r f u l l sedimentation. Recently, Margalef (1974) suggested that the time i n hrs must be a t l e a s t 13 t h r e e times the he i g h t of the chamber i n c e n t i m e t e r s f o r aanoplankton, s i n c e the sedimentation time depends on the kind of organisms. In order t o a s c e r t a i n the minimum necessary s e t t l i n g time, a 100 ml a l i g u o t was allowed t o s e t t l e f o r 18 h r s , the supernatant was t r a n s f e r r e d t o another tube chamber and s e t t l e d again f o r 24 h r s , and the procedure was repeated f o r another 24 hrs. A 10 ml a l i g u o t of o r i g i n a l m a t e r i a l was counted r e p e a t e d l y at 3, 6, 12 and 24 hour p e r i o d of time. Of the 26 s p e c i e s present 19 s p e c i e s had s e t t l e d i n 18 hrs and 23 s p e c i e s i n 24 hrs. Thus, f o r most s p e c i e s , i t appears to be s u f f i c i e n t t o l e t a l i g u o t s s e t t l e f o r 24 hrs i n the 100 ml tube chamber, f o r 18 hrs i n the 50 ml tube chamber, and f o r 6 hrs i n the 10 ml chamber, r e s p e c t i v e l y . The th r e e remaining s p e c i e s u n s e t t l e d a f t e r 24 hrs were u n i d e n t i f i e d c e n t r i c diatoms and very s m a l l diatom s p e c i e s , which were l e s s than 10 um i n diameter and l e n g t h . For t h i s reason, most c e l l counts were made u s i n g 10 ml tube chambers a f t e r 12 hrs. Examinations of s p e c i e s from the s e t t l e d m a t e r i a l were made by Z e i s s Standard OPL I n v e r t e d Microscope eguipped with phase c o n t r a s t . A t o t a l m a g n i f i c a t i o n of x160 was u s u a l l y used f o r cou n t i n g c e l l s . For i d e n t i f i c a t i o n of diatoms x400 and x1000 were used. Permanent s l i d e s mounted with Hyrax (Banna, 1930) were used as w e l l . There are s e v e r a l p o t e n t i a l sources of e r r o r i n t h i s sedimentation method. Because of the poor r e s o l u t i o n o f the 14 i n v e r t e d microscope f o r m a t e r i a l s i n water, complete i d e n t i f i c a t i o n of i n d i v i d u a l s p e c i e s i s o f t e n i m p o s s i b l e . O c c a s i o n a l l y , s i m i l a r taxa were counted together under the i n v e r t e d microscope and r e l a t i v e p r o p o r t i o n s estimated from a prepared s l i d e . Sometimes r a r e s p e c i e s were mistaken f o r members of more common taxa. T h i s source of e r r o r i s d i f f i c u l t t o e v a l u a t e , and w i l l be d i s c u s s e d i n more d e t a i l under i n d i v i d u a l t a x a . The e r r o r due to sub-sampling was taken i n t o c o n s i d e r a t i o n i n the data. T h i s was done by means of f o u r counts of a l i g u o t s . Four 230 ml samples were c o l l e c t e d from the o r i g i n a l 120 0 ml sample and then a 10 ml a l i q u o t was taken from each 230 ml sample a f t e r the b o t t l e had been shaken. A l l f o u r subsamples were allowed to s e t t l e f o r 12 hrs and were counted. S e v e r a l r e s e a r c h e r s have i n v e s t i g a t e d t h i s source of e r r o r . Hasle(1954, 1969) compared t h e number of organisms i n f i v e a l i g u o t s of a sample and found a range from n to 3n i n d i v i d u a l s ; she a l s o found t h a t the c o u n t i n g p r e c i s i o n of some colony-tarming s p e c i e s was even lower. Holmes and Widrig (1956) counted 20 r e p l i c a t e s of each of 2 ml and 10 ml subsamples from a s i n g l e sample and found t h a t s i n g l e - c e l l e d s p e c i e s were c o l l e c t e d at random and counted without b i a s . However, the v a r i a b i l i t y of chain-forming s p e c i e s was higher than random e x p e c t a t i o n due to the clumping of c e l l s i n t o a c h a i n . For these s p e c i e s they suggested t h a t c h a i n s were s e l e c t e d randomly but not i n d i v i d u a l c e l l s . Lund e t a l . (1958) examined the sub-sampling e r r o r f o r fresh-water phytoplankton, at d i f f e r e n t c e l l d e n s i t i e s , with 20 to 30 r e p l i c a t e sub-15 samples. Counting the c o l o n i e s of c o l o n i a l forms they found t h a t only one of t h i r t e e n s p e c i e s was non-randomly sampled (p=0.5). Recently, Venrick (1971, 1972) developed a s t a t i s t i c a l formula f o r the expected t o t a l variance of a s e r i e s o f counts from a randomly d i s t r i b u t e d p o p u l a t i o n . For non-aggregated s p e c i e s she coul d e s t i m a t e the 90% confidence i n t e r v a l about a s i n g l e sample,x, from the i n t e r v a l 0.3x-3 A2x. fiijalitative S p ecies Data Samples from a v e r t i c a l haul between 0-75m a t each s t a t i o n were used t o make permanent s l i d e p r e p a r a t i o n s . For both L M ( l i g h t microscope) and SEM (scanning e l e c t r o n microscope) o b s e r v a t i o n s , the c e l l s were cleaned as d e s c r i b e d by Hasle and F r y x e l l ( 1 9 7 0 ) . To remove o r g a n i c c ontents of the c e l l s the samples were t r e a t e d with concentrated s u l p h u r i c a c i d , and then with s a t u r a t e d potassium permanganate and f i n a l l y were mounted i n Hyrax. A s p e c i e s l i s t was d e r i v e d from both the q u a n t i t a t i v e counts and from an examination o f s l i d e s from the m a t e r i a l . For t h i s purpose a s m a l l a l i q u o t was a l s o taken from the net samples and examined . Analyses f o r Phys i c o - c h e m i c a l Parameters Measurements of temperature and t h e c o l l e c t i o n of samples f o r s a l i n i t y and n u t r i e n t a n a l y ses were made by u s i n g N.I.O b o t t l e s equipped with r e v e r s i n g thermometers. Temperatures were read on board with an accuracy of ± 0.01"C. Hater samples f o r 16 s a l i n i t y a n a l y s i s were brought to the l a b o r a t o r y and s a l i n i t y was estimated by using the Model 601 MK3 Auto-Lab I n d u c t i v e l y Coupled Salinometer [Extended Range Model]. Bater samples f o r each of the f i v e n u t r i e n t s were poured i n t o s e p e r a t e p l a s t i c b o t t l e s , and phosphate , s i l i c a t e , n i t r a t e , n i t r i t e and ammonia were measured i n the l a b o r a t o r y by using the methods d e s c r i b e d by S t r i c k l a n d and Parsons (1968). S t a t i s t i c a l Analyses A stepwise m u l t i p l e r e g r e s s i o n a n a l y s i s was performed on the environmental and diatom data using the UBC (IBM 360/168-Computer) T r i a n g u l a r Regression Package-STPfiEG B0UIINE. T h i s program i s q u i t e s i m i l a r t o BIO MD Computer Program-BMD 02R (Dixon, 1973) which i s a v a i l a b l e at most computer c e n t e r s . The program w r i t e s a r e g r e s s i o n equation f o r the dependent v a r i a b l e i n a s e r i e s of s t e p s , y=a+b1X1+b2X2+...,+bnXn where y= dependent v a r i a b l e (diatom counts i n t h i s case) Xi= environmental parameter bi= p a r t i a l r e g r e s s i o n c o e f f i c i e n t and expresses how much y would change f o r a u n i t change i n X i a= y i n t e r c e p t , the value of y when X i ' s are a l l z e r o ( Z a r , 1974). P a r t i a l F-values f o r v a r i a b l e s i n the model were examined and a s i g n i f i c a n c e l e v e l at 95% was e s t a b l i s h e d . S 2 ( c o e f f i c i e n t of determination) values and standard d e v i a t i o n s were a l s o 17 examined f o r the o v e r a l l value of the model. The r e g r e s s i o n a n a l y s i s was performed i n two st a g e s . In the f i r s t stage a l l of the diatom counts and environmental data were pooled. Secondly, dummy v a r i a b l e s were introduced f o r s t a t i o n s and depths as w e l l as f o r se a s o n a l p e r i o d s (these w i l l be r e f e r r e d to as l o c a t i o n f a c t o r s and season f a c t o r s , r e s p e c t i v e l y ) . By u s i n g these dummy v a r i a b l e s , we can determine whether or not s t a t i o n s , depths or seasons are s i g n i f i c a n t determinants o f the diatom community. Furthermore, such s i g n i f i c a n c e may imply t h a t e i t h e r some environmental f a c t o r not measured i s i n f l u e n c i n g the diatoms or th a t the diatoms behave d i f f e r e n t l y w i t h i n diatom groupings. The number of diatoms per l i t r e was transformed i n t o the lo g a r i t h m of the counts and taken as the dependent v a r i a b l e . The independent v a r i a b l e s were: temperature ( °C) , s a l i n i t y (%° ), phosphate tyig-at P/l) , s i l i c a t e (ug-at S i / 1 ) , n i t r a t e (jug-at N/1), n i t r i t e ( u g - a t N/1) and ammonia(ug-at N/1). The dummy v a r i a b l e s were s p r i n g , summer, f a l l , winter, S t a t i o n 1, S t a t i o n 2, S t a t i o n 3, S t a t i o n 4, S t a t i o n 5, 1 m, 25 m, 50 m and 75 m. In f a c t , these parameters a re not f u l l y independent, but i n b i o l o g i c a l data they are u s u a l l y used as independent v a r i a b l e s f o r the r e l a t i o n s h i p s with organisms (C a s s i e , 1960; A u s t i n , 197 1; S a l s h , 1971). A f f i n i t y index pager (1957) has developed a system and a n a l y s i s of 18 r e c u r r e n t groups based on the co-occurrences of s p e c i e s w i t h i n a sample s e t . T h i s method has been used t o d i s t i n g u i s h zooplankton s p e c i e s group i n the North P a c i f i c Ocean(Fager and McGowan, 1963). The index of a f f i n i t y (I.A.) i s d e f i n e d as the geometric mean of the p r o p o r t i o n of j o i n t occurrences and the measure of s i m i l a r i t y between each p a i r of s p e c i e s and i s c a l c u l a t e d by the e q u a t i o n : I.A. = £ j / (NAxNB^J- 1/2(NB)* Where J = the number of j o i n t occurrences NA = the t o t a l number of occurrences of s p e c i e s A NB = the t o t a l number of occurrences of s p e c i e s a Symbols are assigned so t h a t NA^NB. Species p a i r s f o r which t h i s e x p r e s s i o n i s equal t o or g r e a t e r than 0.50 are c o n s i d e r e d to show a f f i n i t y . 19 RESULTS In order to e v a l u a t e the sampling e r r o r f o r t h i s study, f o u r r e p l i c a t e 230 ml samples were taken from a 1200 ml NIO sampler. From each of these a 10 ml a l i g u o t was allowed to s e t t l e and 12 s p e c i e s o f diatoms were counted. The r e s u l t s of v a r i a b i l i t y o f those counts are given i n Table I I . For c h a i n -forming s p e c i e s both c e l l s and chains were counted. Chi-sguare index i n d i c a t e s whether or not diatom s p e c i e s are randomly sampled <p<0.5). The s p e c i e s showing the g r e a t e s t d e v i a t i o n from random d i s t r i b u t i o n were chain-forming s p e c i e s with the c h a i n s being s e l e c t e d randomly except f o r Skeletonema costatum^ These r e s u l t s support the p r e v i o u s s t u d i e s mentioned above. The l a r g e Chi-sguare value f o r Corethron griop.hJ.lum was somewhat d i s t u r b i n g , and no adguate e x p l a n a t i o n can be o f f e r e d . As environmental f a c t o r s such as water temperature and n u t r i e n t c o n c e n t r a t i o n s change with the seasons, the growth and standing crop of the p l a n k t o n i c diatoms, w i l l a l s o change, as w i l l the diatom component of the community. V a r i a t i o n s i n s a l i n i t y g r a d i e n t a l s o occur s e a s o n a l l y i n the S t r a i t of Georgia/Juan de Fuca S t r a i t system due to the heavy d i s c h a r g e of fresh-water from the F r a s e r R i v e r during summer. These s e a s o n a l v a r i a t i o n s i n environmental f a c t o r s are important t o the ecology of a l l p l a n k t o n i c organisms. The r e s u l t s of the 15 c r u i s e s are presented so as to show the e f f e c t s of such v a r i a t i o n s . Temperature and S a l i n i t y , Table I I . V a r i a b i l i t y of c e l l counts In four r e p l i c a t e aliquots. (counts of colonies are i n brackets) Species 1 10 ml aliquots 2 3 4 X 2 s X2 P r o b a b i l i t y of randomness Skeletonema costatum 4809 (271) 5146 (311) 4516 (288) 4225 (339) 4674 (302) 155858.0 (868 .9) 100.04 (8.63) < .01 .01< p <.05 Chaetoceros d e b l l l s 2471 (352) 2862 (368) 2684 (354) 2111 (314) 2532 (347) 104322.0 (534.6) 123.60 (4.62) <.01 N i t z s c h l a actydrophila 2205 (1062) 2452 (1031) 1908 (985) 2150 (1100) 2179 (1045) 49828.9 (2369.6) 8.61 (6.81) .01 < p < .05 Corethron criophilum 2002 1953 1897 2116 1992 8674.0 13.06 < .01 Thal a s s i o s i r a p a c i f i c a 1526 (305) 1338 (286) 1695 (279) 1587 (322) 1536 (298) 22395.0 (373,3) 43.73 (3.79) < .01 Tha l a s s i o s l r a nordenskioeldii 1120 (294) 983 (252) 1202 (278) 1238 (302) 1135 (281) 12803.3 (486.3) 33.83 (5.18) <.01 Chaetoceros didymus 154 (55) 132 (52) 165 (50) 139 (43) 147 50 220.4 (26.0) 4.48 (1.56) N i t z s c h i a longissima 125 140 131 133 132 38.2 0.87 Chaetoceros s i m i l i s 63 (26) 69 (28) 52 (22) 50 (19) 58 (24) 81.6 (16.2) 4.19 (2.06) Cyllndrotheca closterium 47 42 58 45 48 48.6 3.0 Thalassiosira eccehtricus 27 21 24 22 23 7.0 0.89 Ditylium b r i g h t w e l l i i 8 6 6 5 6 1.1 0.56 X = 2 x 1 s 2 = £(*i-X) 2 y2 = Z ( x l - X ) 2 21 The temporal f l u c t u a t i o n s i n both temperature and s a l i n i t y from 1m t o 75 m at f i v e s t a t i o n s are shown i n Fi g u r e 2 through F i g u r e 6. a l l data c o l l e c t e d d u r i n g 15 c r u i s e s have been repor t e d i n the I n s t i t u t e of Oceanography Data Reports (1972, 1973) . The temperature of the subsurface waters (1 m) at a l l f i v e s t a t i o n s ranged from 5.5°C to 17.7°C with a mean o f 8.7 2; v a l u e s were lowest i n winter and e a r l y s p r i n g , and highest i n l a t e summer and f a l l . T h i s v a r i a t i o n i s mainly due to seasonal changes i n the e f f e c t of s o l a r r a d i a t i o n h eating the water. A comparision of the v e r t i c a l p r o f i l e s of temperature f o r a l l f i v e s t a t i o n s show t h a t S t a t i o n s 1, 2 and 3 i n the S t r a i t of Georgia underwent c o n s i d e r a b l e v a r i a t i o n s i n the upper l a y e r s , while S t a t i o n s 4 and 5 i n Haro S t r a i t and Juan de Fuca S t r a i t showed very s l i g h t seasonal v a r i a t i o n . The o v e r a l l temperature v a r i a t i o n i n the study area was r e l a t i v e l y low. Takahashi, F u j i and Parsons(1973) i n v e s t i g a t e d phytoplankton photosynthesis i n the F r a s e r River e s t u a r y and have shown t h a t temperature i s one of the l i m i t i n g f a c t o r s i n the area, e s p e c i a l l y below 10m. I t i s g e n e r a l l y thought t h a t plankton organisms are able to t o l e r a t e a wide temperature range (Hutchinson, 1967) and the optimum temperature f o r growth i n the sea has been reported as being between 12*C and 20° C(Fogg, 1975); Although i t has been i n d i c a t e d t hat the d i r e c t i n f l u e n c e of temperature on phytoplankton production i n the sea 22 1 9 7 2 1 9 7 3 M J J A S O N D J F M A M J J SALINITY °/oo F i g u r e 2. Seasonal c y c l e o f temperature and s a l i n i t y at s t a t i o n 1. 23 1 9 7 2 1 9 7 3 SALINITY % o Figure 3. Seasonal cy c l e of temperature and s a l i n i t y at s t a t i o n 2. 1 9 7 2 1 9 7 3 M J J A S O N D J F M A M J J T r ^ r———I 1 — 1 • r— 1 , • , , . . : . r. SALINITY °/oo Figure 4. Seasonal cy c l e of temperature and s a l i n i t y at s t a t i o n 3. 25 1972 1 9 7 3 M J J A S O N D J F M A M J J _ . . . . , , , , r — 1 1 - 1 r - r 32 SALINITY % o F i g u r e 5. Seasonal c y c l e o f temperature and s a l i n i t y at s t a t i o n 4. 1972 1973 M J J A S O N D J F M A M J J SALINITY °/o F i g u r e 6. Seasonal c y c l e of temperature and s a l i n i t y at s t a t i o n 5. 27 i s i n s i g n i f i c a n t (Steemann-Nielsen, 1960), c o a s t a l and e s t u a r i n a waters with r a p i d n u t r i e n t r e g e n e r a t i o n processes show s i g n i f i c a n t v a r i a t i o n i n phytoplankton p r o d u c t i o n with temperature(Eppley, 1972), A l s o , there are s i g n i f i c a n t temperature optima f o r d i f f e r e n t s p e c i e s ( B r a a r u d , 1962; Bunt, et a l , , 1966; Smayda, 1973; Soeder and S t e n g e l , 1974). Thus, the p r e v a i l i n g low temperatures and t h e i r seasonal f l u c t u a t i o n s i n the study area are p a r t i c u l a r l y important i n d e t e r m i n i n g the p r i n c i p a l s p e c i e s of diatoms present and p o p u l a t i o n changes. V a r i a t i o n s i n s a l i n i t y are u s u a l l y a s s o c i a t e d with temperature changes. S a l i n i t y v a r i e d from 15.10 to 33.58%©with a mean of 29.76. Low s a l i n i t i e s o c c u r r e d twice, during s p r i n g and summer a t S t a t i o n s 1, 2, and 3. The f i r s t low s a l i n i t i e s i n e a r l y s p r i n g were d i r e c t l y a s s o c i a t e d with the p e r i o d of the g r e a t e s t p r e c i p i t a t i o n and the second low s a l i n i t i e s i n summer were due t o the i n c r e a s e d d i s charge of r i v e r s , mostly from the F r a s e r R i v e r . S a l i n i t i e s at S t a t i o n s 4 and 5 were r e l a t i v e l y c o n s t a n t , showing marine c o n d i t i o n s . At s t a t i o n s 3 and 4 the v e r t i c a l regimes i n s a l i n i t y as w e l l as i n temperature were r e l a t i v e l y homogeneous (except i n summer) i n the 75 m water column. T h i s i s mainly due to the i n t e n s e t i d a l mixing a c t i o n which reduces f r e s h water input i n the upper l a y e r ( H e r l i n v e a u x and Giovando, 1969). In a study of the r e l a t i o n s h i p between the s a l i n e environment and marine fungal d i s t r i b u t i o n i n the S t r a i t of Georgia and Juan de Fuca S t r a i t system, Hughes(196 9) has shown 28 t h a t the e n t i r e area can be d i v i d e d i n t o three hydrographic r e g i o n s on the b a s i s of s a l i n i t y and t h a t the d i s t r i b u t i o n of some f u n g a l groups are a s s o c i a t e d with these environments. According to t h e present data the S t r a i t of Georgia has an e s t u a r i n e - t y p e s a l i n i t y s t r u c t u r e as T u l l y et a l . (1957) have shown, while the areas of Haro S t r a i t and Juan de Fuca S t r a i t are more marine. These d i f f e r e n t f e a t u r e s could be very important i n forming s p e c i e s a s s o c i a t i o n s of p l a n k t o n i c diatom communities i n the study area, because s a l i n i t y has c o n s i d e r a b l e p h y s i o l o g i c a l e f f e c t upon p l a n k t o n i c a l g a e (Soeder and S t e n g e l , 1974) and v a r i a t i o n s i n t o t a l s a l t content of water may i n h i b i t the s p a t i a l d i s t r i b u t i o n of phytoplankton organisms (Boney, 1975) . P l a n t N u t r i e n t s Marked se a s o n a l v a r i a t i o n s i n n u t r i e n t c o n c e n t r a t i o n s were e v i d e n t at S t a t i o n s 1 through 5. These v a r i a t i o n s o c c u r r e d between the s u r f a c e and 75 m. The c o n c e n t r a t i o n range of phosphorus during t h i s study was 0.3-2.8 ^g- a t P / l with a mean of 1.7 (Table III) except a t s t a t i o n 1 i n March 1973 when the phosphorus c o n c e n t r a t i o n s below 25m were undetectable. The reason f o r these unusual v a l u e s of phosphorus c o n c e n t r a t i o n are not known. Seasonal d i s t r i b u t i o n was very s i m i l a r t o t h a t p r e v i o u s l y observed i n the S t r a i t of Georgia(Parsons et a l . , 1973; Stockner and C l i f f , 1975). Low l e v e l s p r e v a i l e d d u r i n g summer through f a l l , f o l l o w e d by Table I I I . Phosphorus concentrations (ug-at/1) during May 1972-July 1973 Station /Depth 19 72 May Jun. J u l . Aug. Sep. Oct. Nov. Dec. 1973 Jan. Feb. Mar. Apr. May Jun. J u l . 1- lm 0.9 0.8 0.7 0.0 0.2 0.8 2.0 1.9 1.1 2.1 2.0 0.8 0.3 0. 3 0.5 25m 2.1 1.7 1.8 1.3 1.8 1.4 2.8 2.0 1.6 2.0 0.0 2.5 2.2 2.1 2.2 50m 2.1 1.6 1.9 1-5 2.0 1.4 2.6 1.9 1.6 2.2 0.0 2.0 2.3 2.6 2.0 75m 2.3 2.0 1.8 1.6 2.1 1.4 2.8 2.2 1.6 2.1 0.0 2.6 2.2 2.7 2.3 2- lm 2.6 1.5 o. 6 0.0 0.6 0.9 2.0 1.7 1.5 1.5 1.6 0.9 0.9 0. 7 0.6 25m 2.2 1.8 1.6 1.2 1.6 1.3 2.4 1.9 1.5 1.8 2.1 2.2 2.2 1.7 1.5 50m 2.1 1.8. 1.7 1.4 1.6 1.2 2.4 2.2 1.4 1.9 1.5 2.4 1.9 1.4 1.8 75m 2.5 1.9 1.7 1.4 1.7 1.2 2.4 2.0 1.4 2.2 1.9 2.5 1.9 1.4 2.0 3- lm 1.3 0.7 1.4 0.2 0.7 1.0 2.1 1.8 1.2. 2.1 2.0 1.6 1.8 1.9 0. 7 25m 1.9 1.4 1.6 1.0 1. 7 1.2 2.4 1.9 1.3 2.1 2.0 2.0 1.9 1.8 1.5 50m 2.2 1.8 1.6 1.2 2.0 1.2 2.2 1.9 1.3 2.2 1.8 2.3 2.0 2.3 1.8 75m 2.1 1.6 1. 7 1.1 1.9 1.2 2.4 2.0 1.3 1.6 1.9 2.0 1.1 2.3 1. 7 4- lm 2.0 1.4 1.7 0.8 1.5 1.3 2.5 1.9 1.0 1. 7 1.8 1. 7 2.0 2.0 1. 7 25m 2.1 1.2 1.7 1.2 2.1 1.2 2.5 2.1 1.1 1.6 1.8 3.0 1.9 1.9 1.9 50m 2.3 1.5 1.8 1.6 2.0 1.2 2.4 1.9 1.3 1.6 2.0 2.2 2.1 2.0 2.1 75m 2.3 1.5 1.8 1.6 2.1 1.2 2.5 2.2 1.3 1.5 1.6 2.4 2.0 2.1 2.0 5- lm 2.0 1.4 1.7 o.9 1. 7 1.3 2.4 2.0 0.7 1.4 1.6 1.9 1.9 2.2 1.5 25m 2.1 1.5 1.7 1.2 2.0 1.3 2.4 2.1 1.9 1.5 1.6 2.0 2.1 2.0 2.0 50m 2.1 1.6 1.9 1.5 1.9 1.3 2.3 2.1 1.2 1.5 1. 7 2.1 1.8 2.3 2.0 75m 2.4 1.6 1.8 1.5 1.9 1.5 2.3 1.9 1.2 1.4 1.6 2.4 2.1 2.6 2.0 Table IV. N i t r a t e c o n c e n t r a t i o n s (^jg-at/1) during May 1972 - J u l y 1973 S t a t i o n 1972 1973 /Depth May J u n . J u l . Aug. Sep. Oct . Nov. Dec. J a n . Feb. Mar. Apr. May J u n . J u l . 1- lm 27.5 24.1 5.9 2.3 1.2 14.5 12.1 24.4 20.2 18.4 24.3 0.3 3.8 0.5 0.0 25m 14.3 30.2 26.7 27.9 26.2 26.8 20.7 23.5 25.1 21.3 26.2 26.2 18.1 9.3 11.8 50m 24.6 32.1 26.6 23.1 28.6 25.9 23.6 26.8 27.8 24.6 26.0 26.1 25.9 10.9 14.0 75m 24.5 27.6 26.5 29.3 28.6 29.4 21.0 28.3 15.5 18.7 24.5 25.5 26.4 0.9 14.5 2- lm 11.7 5.5 4.3 2.6 4.6 15.9 18.9 25.4 15.5 16.3 20.1 2.8 9.6 7.5 1.2 25m 16.1 25.1 23.9 23.5 23.0 27.6 22.8 25.7 19.3 16.9 25.3 24.8 27.0 12.3 9.7 50m 21.1 24.4 26.6 23.1 23.6 22.2 11.7 27.5 25.0 15.8 24.4 25.1 23.1 7.2 9.7 75m 24.6 22.9 26.4 23.8 24.6 22.0 18.8 27.0 22.7 14.8 22.6 23.4 22.5 23.7 18.8 3- lm 24.6 6.1 19.6 4.8 6.6 17.1 18.2 26.3 19.2 12.2 21.9 12.6 16.5 14.4 2.1 25m 13.2 24.8 20.9 21.0 21.5 22.3 17.0 26.3 17.6 13.3 22.5 19.4 19.3 6.3 7.3 50m 24.3 16.9 19.8 20.7 21.1 22.8 13.3 26.2 20.0 13.3 21.9 20.1 22.3 13.4 9.8 75m 24.8 19.1 18.6 22.4 22.6 23.1 16.5 26.0 19.3 15.8 22.5 20.4 22.4 16.2 10.5 4- lm 23.8 20.0 23.9 14.3 17.1 25.4 21.6 26.4 16.9 15.2 18.9 19.0 20.7 10.5 4.9 25m 23.9 23.4 24.6 21.8 23.4 26.0 17.3 26.6 15.9 13.4 20.1 20.2 21.3 8.3 7.3 50m 16.2 - 24.8 25.3 24.4 20.2 17.9 26.4 24.9 15.8 20.4 21.2 21.8 17.2 13.0 75m 23.7 26.4 25.1 25.5 23.0. 24.2 18.3 26.5 17.4 16.0 19.8 21.1 22.2 17.3 11.6 5- lm 23.6 23.4 21.9 15.0 23.0 25.0 17.5 25.6 8.9 13.0 17.9 20.8 23.5 10.9 8.4 25m 15.9 24.7 25.8 22.7 26.9 26.6 20.2 25.9 12.5 11.3 17.8 21.7 23.9 21.6 8.0 50m 23.8 26.6 26.3 23.3 27.3 27.6 19.7 25.8 18.2 13.0 18.2 27.0 25.1 6.4 11.4 75m 23.2 23.6 27.3 29.4 28.1 31.2 19.7 25.8 11.5 12.6 16.1 22.5 22.5 20.0 12.9 Table V. N i t r i t e concentrations (ug-at/1) during May 1972 - July 1973 Station /Depth 1- lm 25m 50m - 75m 2- lm 25m 50m 75m 3- lm 25m 50m 75m 4- lm 25m 50m 75m 5- lm 25m 50m 75m 1972 May Jun. J u l . Aug. Sep. Oct. Nov. 0.1 0.2 0.1 0.2 0.3 0.3 0.1 0.3 0.3 0.4 0.3 0.4 0.4 0.3 0.4 0.3 0.3 0.3 0.4 0.2 0.2 0.1 0.0 0.1 0.4 0.3 0.2 0.2 0.2 0.3 0.2 0.2 0.3 0.2 0.0 0.2 0.2 0.2 0.2 0.2 0.2 0.0 0.0 0.1 0.1 0.1 0.1 0.2 0.2 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.0 0.0 0.3 0.4 0.0 0.0 0.3 0.2 0.2 0.2 0.2 0.3 0.2 0.2 0.2 0.2 0.1 0.0 0.0 0.0 0.2 0.1 0.3 0.2 0.2 0.2 0.2 0.2 0.3 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.3 0.1 0.1 0.1 0.2 0.2 0.2 0.1 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.3 0.3 0.3 0.3 0.1 0.2 0.0 0.0 0.4 0.2 0.1 0.1 0.5 0.4 0.3 0.3 0.3 0.2 0.3 0.3 0.2 0.2 0.3 0.3 0.3 Dec. 0.2 0.2 0.0 0.0 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.0 0.1 0.1 0.1 1973 Jan. Feb. 0.0 0.0 0.0 0.0 0.1 0.0 0.1 0.0 0.1 0.0 0.0 0.1 0.0 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.0 0.0 0.2 0.0 0.1 0.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.0 0.0 0.0 Mar. 0.2 0.0 0.0 0.0 0.2 0.0 0.0 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 Apr. May Jun. J u l . 0.1 0.2 0.1 0.0 0.1 0.1 0.2 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.0 0.2 0.1 0.0 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.0 0.4 0.3 0.0 0.1 0.5 0.4 0.2 0.3 0.2 0.2 0.2 0.3 0.3 0.3 0.2 0.3 0.3 0.2 0.2 0.0 0.1 0.1 0.0 0.1 0.4 0.4 0.5 0.2 0.2 0.2 0.3 0.2 0.2 0.2 0.2 0.3 0.2 0.3 0.2 Table VI. Ammonia c o n c e n t r a t i o n s Qug-at/1) d u r i n g May 1972 - July 1973 Station 1972 1973 /Depth May Jun. J u l . Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun. J u l . 1- lm 1.5 2.1 0.8 1.2 1.2 1.2 1.9. 1.4 1. 7 1.3 0.5 0.5 0.2 1.5 1.3 25m 2.1 0.7 0.6 1.1 1.1 1.3 2.0 1.3 1.4 1.3 0.6 0.6 1.4 2.2 0.3 50m 2.1 1.1 0.6 1.0 - 1.3 2.0 1.2 1.4 0.5 0.6 0.6 0.1 1. 3 0.3 - 75m 1.6 0.8 0.6 1.1 1.1 1.0 1.8 1.3 1.6 1.1 0.5 0.6 0.4 1.0 0.8 2- lm 1.5 4.0 0.0 1.9 1.5 1.7 1.9 1.5 1.6 1.3 0.7 0.5 1.5 2.5 1.9 25m 0.9 1.2 0.0 1.1 1.0 1.2 2.0 1.2 1.4 1.2 0.5 0.4 0.3 1.9 1.6 50m 1.4 1.7 0.7 1.0 1.1 1.4 2.0 1.2 1.3 1.3 0. 6 0.4 0.6 1.3 1.9 75m 1.4 1.9 0.7 1.5 1.2 1.5 1.7 1.3 1.3 1.4 0.6 0.4 0.5 1.2 1.5 3- lm 1.5 1.4 0.9 1.5 1.4 1.6 2.3 1.3 1.3 0.9 0.5 0.5 0.5 1.6 1.1 25m 2.0 1.5 0.9 1.6 1.2 1.5 2.5 1.4 1.4 1.4 0.5 0.5 0. 7 1.9 1.4 50m 1.9 1.5 1.0 2.0 1.3 1.6 2.2 1.2 1.4 0.2 0.5 0.6 0.9 2.0 1.3 75m 2.2 1.5 1.0 1.8 1.3 1.6 1.9 1.5 1.4 0.2 0.5 0.6 0.9 1.8 1.4 4- lm 1.3 1.5 1.0 1.2 1.4 1.6 2.3 2.1 1.4 1.4 0.5 0.6 0.0 1.8 1.1 25m 1.3 1.4 1.0 1.7 1.3 1.5 2.1 2.2 1.4 1.4 0.5 0. 7 0.4 1.7 1.8 50m 1.4 1.3 1-1 1.6 i.3 1.6 2.5 2.1 1.4 1.1 0.4 0.9 0. 7 1.8 1.6 75m 1.5 1.4 1.0 1.5 1.3 1.4 2.0 2.2 1.5 1.2 0.5 0.6 0.5 1.8 1.2 5- lm 2.8 1.1 0.8 1.4 1.3 1.4 2.3 1.3 1.5 1.4 0.4 0.6 0. 7 1. 7 1.0 25m 1. 7 1.0 0.8 1.6 1.2 1.5 2.0 1.2 1.4 1.2 0. 7 0.5 0.6 1.5 1.4 50m 1.5 1.5 0.8 1.3 1.5 1.7 2.1 1.3 1.4 1.2 0.5 0.6 0.4 0.0 1.2 75m 1.5 0.8 0.6 1.2 1.1 - 1.9 1.3 1.3 1.3 0.5 0.6 0.1 0.0 1.2 Table VII. S i l i c a t e concentrations tyig-at/1) during May 1972 - July 1973 Station 1972 1973 /Depth May Jun. J u l . Aug. Sep. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun. J u l . 1-- lm 37.3 17.1 33.3 36.2 14.7 8.4 21.2 25m 21.0 17.0 6.9 42.8 46.8 24.3 33.8 50m 35.2 18.2 5.8 45.0 47.6 7.5 42.5 75m 35.1 17.0 6.6 45.2 45.8 5.3 14.9 2-- lm 9.2 17.0 - 35.8 31.1 26.8 17.3 25m 22.2 17.0 28.4 43.4 27.7 19.6 12.6 50m 25.7 17.3 11.3 44.5 43.8 18.9 18.7 75m 33.6 15.5 11.3 45.2 38.2 16.1 7.9 3-- lm 10.3 17.0 7.6 20.0 34. 7 6.2 34.8 25m 33.5 17.0 6.7 39.7 38.7 7.7 28.2 50m 35.2 16.9 6.9 40.0 41.5 25.1 18.4 75m 35.2 16.9 6.2 31.9 24.6 17.4 18.3 4-- lm 9.9 11.1 • 8.0 41.1 24.8 30.8 33.3 25m 35.2 16.8 13.8 43.4 31. 7 19.8 21.4 50m 5.8 16.9 15.6 46.2 31.4 30.1 10.4 75m 35.2 20.0 9.8 33.3 22.5 33.6 31.8 5-• lm 35.2 8.9 9.6 42.0 40.4 32.0 32.5 25m 15.4 17.0 12.4 43.0 45.1 27.9 18.4 50m 35.1 17.0 6.0 44.7 34.9 12.9 21.2 75m 22.4 16.9 6.4 38.9 41.1 6.9 31.5 52.3 - 57. 6 57. 1 4.8 21.6 8.3 25.9 42.2 32.5 48. 0 58. 8 18.8 47.9 40.9 41.1 49.6 40.7 46. 7 54. 8 20.1 51.0 50.2 46.4 47.7 27.8 68. 5 - 21.6 50.3 53.0 34.6 47.8 23.8 55. 2 55. 9 4.7 31.2 37.5 26.5 48.8 35.4 49. 6 55. 1 25.0 46.5 38.4 37.1 53.9 30.2 51. 0 50. 8 25.6 46.2 44.3 38.1 50.6 36.7 53. 6 36. 4 20.9 42.9 45.8 37.9 52.3 29.5 65. 6 48. 1 11.4 39. 3 39. 6 25.3 50.0 27.5 41. 5 50. 0 14.1 29.0 34.1 35.3 49.5 35.8 46. 1 47. 8 20.4 40.0 33.5 39.6 49.9 29.5 55. 4 47. 9 24.4 43.7 - 30.3 50.6 21.0 48. 7 38. 9 20. 7 40.2 39.5 23.3 50.0 21.3 34. 3 43. 2 27.1 40.0 37.8 27.1 50.9 25.4 23. 1 41. 2 21.3 40.8 40.0 32.5 49.5 22.6 41. 0 42. 0 18.4 42.9 43.6 40.7 45.8 16.6 37. 5: 32. 6 14.8 45.7 44.5 24.1 47.1 19.2 27. 1 33. 2 11.4 45.0 46.3 24.1 43. 7 25.0 25. 3 34. 7 17.2 45.7 47.5 36.5 49.4 26.5 29. 5 35. 6 29.2 41.6 52.0 45.5 34 i n c r e a s i n g c o n c e n t r a t i o n s i n November, and high l e v e l s i n winter. S p r i n g was c h a r a c t e r i z e d by decreasing c o n c e n t r a t i o n s . R e l a t i v e l y s m a l l d i f f e r e n c e s were observed below 25m, although t h e r e were somewhat marked v a r i a t i o n s at S t a t i o n s 3 and 4. Values of phosphorus at S t a t i o n s 4 and 5 showed peaks i n A p r i l through J u l y and i n November through December r e s p e c t i v e l y . Phosphorus c o n c e n t r a t i o n s i n the study area are much higher throughout most of the year than those known t o l i m i t phytoplankton growth. , For example, a value of ca. 0.6 /ig-at P / l has been r e p o r t e d as growth l i m i t i n g by Kuhl(1974). S t r i c k l a n d and A u s t i n (1960) , and M c A l l i s t e r e t a l . (1961) r e p o r t e d t h a t phosphorus r e s e r v e s were never exhausted o f the S t r a i t of Georgia. However, present data show that t h i s i s not the case(see Table I I I ) Data f o r n i t r o g e n c o n c e n t r a t i o n are separated i n t o the three forms, n i t r a t e , n i t r i t e and ammonia. Recorded c o n c e n t r a t i o n s of n i t r a t e - n i t r o g e n ( T a b l e IV) ranged from undetectable t o 32.1 /ig-at N/1 with a mean value o f 19.59. Marked seasonal v a r i a t i o n s were ev i d e n t throughout the s t a t i o n s i n the upper 25m l e v e l . As i n d i c a t e d n i t r a t e was more or l e s s homogeneous i n v e r t i c a l d i s t r i b u t i o n below 25m except d u r i n g the summer months. T h i s v e r t i c a l p r o f i l e of n i t r a t e i s s i m i l a r to those of phosphate. The g e n e r a l s t r u c t u r e of annual n i t r a t e v alues shows t h a t l e v e l s were high during winter and s p r i n g , and low d u r i n g the r e s t of the year. However, the p a t t e r n i n 1972 was somewhat d i f f e r e n t from t h a t i n 1973. Takahashi, F u j i and Parsons(1973) p o i n t e d out t h a t n i t r a t e below 1 /ig-at N/1 i s a l i m i t i n g f a c t o r f o r phytoplankton photosynthesis i n the F r a s e r 35 River e s t u a r y . During the present study n i t r a t e c o n c e n t r a t i o n s below 1 ng-at N/1 occurred only i n the subsurface water duri n g the summer monthe of 1973 at S t a t i o n 1 and at 1m i n June at S t a t i o n 2. This i n d i c a t e s t h a t n i t r a t e i s r a r e l y l i m i t i n g with depth. However, some l i m i t i n g l e v e l s occurred i n the s u r f a c e zone a t a l l s t a t i o n s . N i t r i t e n i t r o g e n was u s u a l l y found i n the water of the study area i n amounts ranging from 0.0 to 0.5 yug-at N/1 with a mean of 0.16 (Table V). The high values were observed during s p r i n g months at S t a t i o n s 1 and 2, and during the s p r i n g and summer months at S t a t i o n s 3, 4 and 5, showing the h i g h e s t values below 25m, while low values were observed i n the winter months at a l l s t a t i o n s . The seasonal d i s t r i b u t i o n o f n i t r i t e was s i m i l a r to the r e s u l t s given by Stephens e t a l . (1967). < Ammonia-nitrogen c o n c e n t r a t i o n v a r i e d from 0.0 to 2.8 yag-at N/1 with a mean value of 1.23(Table VI). No c o n s i s t e n t depth d i f f e r e n c e s were noted. Low values i n ammonia c o n c e n t r a t i o n s were e v i d e n t i n J u l y 1972 and during s p r i n g months i n 1973. The c o n c e n t r a t i o n s o f ammonia i n c r e a s e d i n l a t e summer and were high u n t i l l a t e winter. High c o n c e n t r a t i o n s of ammonia u s u a l l y c o i n c i d e d with diatom blooms. In g e n e r a l the seasonal d i s t r i b u t i o n s o f n i t r o g e n was s i m i l a r to those observed f o r the S t r a i t of Georgia by F u l t o n et a l . ( 1967, 1968) and d e s c r i b e d p r e v i o u s l y f o r the S t r a i t of Georgia/Juan de Fuca system by T u l l y and Dodimead (1957). T h e i r data suggest t h a t the entrainment of fresh-water i n p u t from the 36 F r a s e r River provided n i t r o g e n f o r the study area, while ocean waters, i n c l u d i n g Juan de Fuca s t r a i t and the passages, were mainly r e s p o n s i b l e f o r the phosphorus c o n c e n t r a t i o n of the area. The seasonal v a r i a t i o n s of r e a c t i v e s i l i c a t e were more e v i d e n t i n the study area and ranged from 4.7 t o 68.5 ^ig-at/1 with a mean of 31.5(Table V I I ) . During the l a t e f a l l the c o n c e n t r a t i o n of s i l i c a t e i n c r e a s e d , reaching a high c o n c e n t r a t i o n i n winter and decreasing during s p r i n g and summer. The f i r s t low c o n c e n t r a t i o n s occurred i n A p r i l and i n J u l y 1973. T h i s p a t t e r n of annual v a r i a t i o n i n s i l i c a t e c o n c e n t r a t i o n i s s i m i l a r t o t h a t observed by Parsons e t a l . ( 1 9 7 0 ) , and i s d i r e c t l y a s s o c i a t e d with the p e r i o d s of diatom blooming i n the area. The c o n c e n t r a t i o n s i n the upper r e g i o n s of the S t r a i t of Georgia/Juan de Fuca system were hi g h , while those i n the lower r e g i o n s e s p e c i a l l y at S t a t i o n 4 were low. T h i s i n d i c a t e s t h a t the p r i n c i p l e source of s i l i c a t e i n the study area i s the F r a s e r R i v e r ( T u l l y and Dodimead, 1957). The Diatoms The temporal v a r i a b i l i t y i n the t o t a l standing c r o p of the diatom community i n the study area i s shown i n Fi g u r e s 7 through 11. Of p a r t i c u l a r i n t e r e s t to t h i s study are the s i z e s and t i m i n g of any f l u c t u a t i o n s which r e o c c u r i n an annual c y c l e . The gene r a l p a t t e r n of the annual c y c l e of the diatom community was a r a p i d i n c r e a s e i n the st a n d i n g crop i n A p r i l f o l l o w e d by a sharp decrease i n May, and then a second peak i n the s t a n d i n g crop which occ u r r e d d u r i n g the e a r l y summer months with diatoms L O G i 0 D I A T O M C E L L S / L I T E R CO on Ov v| ''LZ 1 m \ / / 25 m \ ' 50 m V 75 m f 8 9 10 11 12 1 2 3 4 19 73 T I M E ( M O N T H S ) F i g u r e 8. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 2. 7 CO u O p-< 4 Q o O O 3r 5 6 7 8 9 10 11 12 1 2 3 4 1972 1973 T IME ( M O N T H S ) Figure 9. Seasonal f l u c t u a t i o n s i n t o t a l diatom standing crop at s t a t i o n 3. LO VO 07 42 remaining r e l a t i v e l y abundant. The peak of the f a l l diatom p o p u l a t i o n at S t a t i o n s 1 and 3 was lower than t h a t of s p r i n g . The s t a n d i n g crop d u r i n g the winter months reached a minimum. The seasonal v a r i a t i o n of the standing crop of diatoms(between the s u r f a c e and 75m) at a l l s t a t i o n s a p p a r e n t l y showed s i m i l a r p a t t e r n s except at S t a t i o n 2j the s i z e of the standing crop both at 50 m and 75 m was u s u a l l y much lower than i n the upper l a y e r . The annual c y c l e i n the standing crop at S t a t i o n 2 ( F i g u r e 8) was c h a r a c t e r i z e d by a l a r g e i n c r e a s e during s p r i n g months(except at 25m). No i n d i c a t i o n of a f a l l peak i n diatom f l u c t u a t i o n was observed. V e r t i c a l v a r i a t i o n s i n the standing crop at S t a t i o n s 3 and 4 were much l e s s than i n the other three S t a t i o n s ( F i g u r e 9 and 10), i n d i c a t i n g the probable e f f e c t of t i d a l mixing (Herlinveaux and Giovando, 1969) on the standing crop of diatoms. V e r t i c a l d i s t r i b u t i o n of diatom p o p u l a t i o n v a r i e d markedly at a l l s t a t i o n s d u r i n g s p r i n g (April-May) and i n August. The dominant s p e c i e s was ' Skeletonema costatum. In J u l y 1972, S e h r o e d e r e l l a d e l i c a t u i a was dominant i n the subsurface water at S t a t i o n 1. In October, Corethrgn crio£hilum was dominant at S t a t i o n s 1-4 and d u r i n g s p r i n g and winter (December-March) P a r a l i a s u l c a t a was dominant at a l l s t a t i o n s . Chaetoceros c o n c a y i c g r n i s was dominant at S t a t i o n s 1 and 2 i n November. The highest s t a n d i n g crop of diatoms, more than 1,000,000 c e l l s per l i t e r , was observed during l a t e spring and summer at a l l s t a t i o n s . The few previous phytoplankton o b s e r v a t i o n s i n the 43 study area are i n agreement and a l s o show that a r i c h s t a n d i n g crop cf phytoplankton i s a c h a r a c t e r i s t i c f e a t u r e of the spring/summer months (Hutchinson and Lucas, 1931; Legare, 1957). During f a l l , a diatom maximum was observed at S t a t i o n s 1 and 3. The maximum f a l l s t a n d i n g c r o p , however, was u s u a l l y l e s s than the maximum s p r i n g or summer standing crop. At the other 3 s t a t i o n s very high c o n c e n t r a t i o n s were observed d u r i n g l a t e s p r i n g and summer. Small seasonal f l u c t u a t i o n s have a l s o been observed. Thus, two p a t t e r n s of sea s o n a l d i s t r i b u t i o n i n the diatom standing crop are d i s t i n g u i s h e d i n the study a r e a . A t o t a l of 219 s p e c i e s of diatom s p e c i e s were encountered d u r i n g t h i s study. These taxa c o n s i s t e d of 171 marine s p e c i e s , 8 brackish-water s p e c i e s , 11 marine/brackish water s p e c i e s and 29 fresh-water s p e c i e s which were i n t r o d u c e d from the F r a s e r River and other r i v e r s . The seasonal d i s t r i b u t i o n of i n d i v i d u a l s p e c i e s was extremely v a r i a b l e . Some s p e c i e s demonstrated a c o n s i d e r a b l e i n c r e a s e i n standing crop f o r one or two months while many others' were very common but never abundant. Many s p e c i e s were c h a r a c t e r i z e d by s m a l l p o p u l a t i o n s or they were absent over most of the year. The abundance and h a b i t a t s of the s p e c i e s t r e a t e d are summarized i n Table V I I I , The diatoms are grouped i n t o s i x groups a c c o r d i n g t o abundance and frequency of o b s e r v a t i o n . In group 1(Table VIII) 33 diatom taxa were found to be abundant and frequent i n water samples with a maximum abundance of 5000 c e l l s or more per l i t e r . The maximum value was observed to be 1,9 90,000 i n 44 Table VIII. The abundances and habitats* of diatom species in the Strait of Georgia/Juan de Fuca Strait system. (Species arranged by habitat) Key to the abbreviations: Bor : boreal (northern but not arctic) Br : brackish-water C : common (observed more than 10 times) Col : cold water (higher latitudes than approx. 60 N & S) Cos : cosmopolitan Est : estuarine Fr : fresh water L i : l i t t o r a l Mar : marine** Ner : n e r i t i c Oce : oceanic R : rare (observed once) Tem : temperate (the region between cold and warm waters) Tyc : tychopelagic VR : very rare (observed 2-3 times ) War : warm water (the region between 30-45 N and 20-40 S) *Habitat in this table refers to the best known habitat which have been defined in the literature (e.g. Cupp, 1943; Smayda, 1958; Hendey, 1964; Simonsen, 1974). **Marine species include the species whose best habitats are not clear. T a b l e V I I I . ( c o n t i n u e d ) . Group 1 . S p e c i e s frequent and Species abundant i n water sample Maximum abundance H a b i t a t c e l l / 1 A s t e r i o n e l l a g l a c i a l i s 58000 C o s - N e r - T r o --Tern Chaetoceros a f f i n i s 39200 Ner-Tem Chaetoceros compressus 30800 Cos-Ner-Bor--Tem Chaetoceros c o n c a v i c o r n i s 79500 C o l Chaetoceros c o n s t r i c t u s 11200 * Ner-Tem Chaetoceros convoltus 9200 O c e - C o l - B o r Chaetoceros d e b i l i s 357100 N e r - C o l - B o r Chaetoceros d e c i p i e n s 11400 C o s - N e r - C o l --Bor Chaetoceros didymus 13200 Neir-Tem Chaetoceros d i f f i c i l i s 68800 Ner-Tem Chaetoceros r a d i c a n s 31600 Cos-Ner Chaetoceros s i m i l i s 244 00 Ner-Tem Chaetoceros subsecundus 22400 N e r - C o l - B o r Cocconeis c o s t a t a 8500 M a r - L i Corethron c r i o p h i l u m 2003 00 Oce-Tem C o s c i n o d i s c u s l i n e a t u s 57 00 Cos-Oce-Ner C y l i n d r o t h e c a c l o s t e r i u m 132 00 Cos-Br Ditylum b r i g h t w e l l i i 924 00 Ner-Tem Grammatophora marina 63 00 M a r - L i L e p t o c y l i n d r u s danicus 307 00 Ner-Tem M e l o s i r a i t a l i c a 80 00 F r - M a r - L i N i t z s c h i a d e l i c a t u l a 2205 00 Mar-Ner? T a b l e V I I I ( c o n t i n u e d ) . Group 1. Species frequent and abundant i n water sample Species Maximum abundace c e l l / 1 H a b i t a t N i t z s c h i a l o n g i s s i m a 58800 Cos-Ner N i t z s c h i a pungens 9200 Cos-Ner-War N i t z s c h i a s e r i a t a 34800 Ner-Tem-Col P a r a l i a s u l c a t a 28400 Mar-Tyc S c h r o e d e r e l l a d e l i c a t u l a 165800 Cos-Tem-War Skeletonema costatum 1990000 Ner-Col-Tem-War Thalassionema n i t z s c h i o i d e s 76200 Cos-Ner T h a l a s s i o s i r a a e s t i v a l i s 50400 Ner-Tem? T h a l a s s i o s i r a e c c e n t r i c u s 10600 Cos-Oce T h a l a s s i o s i r a r o t u l a 80000 Ner-Tem T h a l a s s i o s i r a sp. B 12800 Ner? roup 2.Species frequent and abundant only d u r i n g one or two seasons Species Maximum abundance c e l l / 1 H a b i t a t C e r a t a u l i n a b e r g o n i i 13000 Cos-Ner-War Chaetoceros b r e v i s 27700 Ner-War Chaetoceros l a c i n i o s u s 7200 Ner-Tem Chaetoceros p s e u d o c r i n i t u s 7600 Ner-Tem Chaetoceros s o c i a l i s 726100 Ner-Tem Chaetoceros v a n h e u r c k i i 10400 Ner-Tem Eucampia zodiacus 44800 Cos-Ner N i t z s c h i a a c t y d r o p h i l a 16400 Ner-Tem R h i z o s o l e n i a d e l i c a t u l a 56500 Ner-Tem 47 Table V I I I ( c o n t i n u e d ) . Group 2. Species frequent and abundant o n l y d u r i n g one or two seasons Species Maximum abundance H a b i t a t c e l l s / 1 T h a l a s s i o t h r i x f r a u e n f e l d i i 2000 Oce-War T h a l a s s i o s i r a d e c i p i e n s 9200 Ner-Tem T h a l a s s i o s i r a n o r d e n s k i o e l d i i 172800 N e r - C o l - B o r T h a l a s s i o s i r a p a c i f i c a 523800 Ner-Tem T h a l a s s i o s i r a p o l y c h o r d a 23000 Ner-Tem T h a l a s s i o s i r a sp. A ?* Ner? 3roup 3- Species frequent i n water sample, but maximum abundance l e s s than 50 c e l l s / 1 0 ml Species Maximum abundance c e l l s / 1 H a b i t a t Actynoptychus s e r a n i u s 600 Cos-Oce-Ner B i d d u l p h i a a u r i t a 1900 Cos-Ner Chaetoceros a f f i n i s v a r . w i l l e i 2000 Ner? Cocconeis s c u t e l l u m 2200 C o s - M a r - L i C o s c i n o d i s c u s c e n t r a l i s v a r . p a c i f i c a 900 Oce-Tem C o s c i n o d i s c u s obscurus 600 Oce C o s c i n o d i s c u s o c u l u s - i r i d i s 300 Cos-Oce C o s c i n o d i s c u s r a d i a t u s 1600 Cos-Oce-Ner C o s c i n o d i s c u s s t e l l a r i s 800 Oce-Ner C o s c i n o d i s c u s w a i l e s i i 1400 Ner F r a g i l a r i a capucina 1800 F r Licmophora a b b r e v i a t a 600 M a r - L i L e p t o c y l i n d r u s mediterraneus 1400 Ner-Oce * T h i s s p e c i e s was cofused w i t h Th. polychorda i n c o u n t i n g . 48 Table V I I I ( c o n t i n u e d ) . Group 3. Species frequent i n water sample, but maximum abundance l e s s than 50 c e l l s / 1 0 ml Species Maximum abundance c e l l s / 1 H a b i t a t N a v i c u l a sal inarum 2600 Cos-Br Pleurosigma normanii 200 M a r - L i - T y c ? R h i z o s o l e n i a s e t i g e r a 70000 Ner-Tem Synedra ulna 800 C o s - F r T h a l a s s i o s i r a a n g s t i i 500 Ner? T r o p i d o n e i s a n t a r c t i c a v a r . p o l y p l a s t a 200 Ner roup 4. Species frequent i n water sample d u r i n g one or two seasons, but maximum abundance l e s s than 50 c e l l s / 1 0 ml Species Maximum abundance H a b i t a t c e l l s / 1 B i d d u l p h i a l o n g i c r u r i s 3000 Ste-Ner-Tem B i d d u l p h i a l o n g i c r u r i s v a r . h y a l i n a 1300 Ner-Tem B i d d u l p h i a obtusa 1300 Mar-Tyc Chaetoceros l o r e n z i a n u s 2600 Ner-War Cocconeis d i r u p t a 200 M a r - L i Cocconeis d i s c u l o i d e s 800 M a r - L i C o s c i n o d i s c u s asteromphalus 200 Cos-Oce C o s c i n o d i s c u s g r a n i i 600 Cos-Oce C o s c i n o d i s c u s marginatus 300 Oce-Tem C y c l o t e l l a s t r i a t a 400 M a r - B r F r a g i l a r i a s t r i a t u l a 2100 Ner-Tem N a v i c u l a complanatoides 700 Mar Pleurosigma formosa 1700 Mar T a b l e V I I I ( c o n t i n u e d ) . Group 4 . S p e c i e s frequent i n water sample d u r i n g one or two seasons, but maximum abundance l e s s than 50 c e l l s / 1 0 ml Species Maximum abundance H a b i t a t c e l l s / 1 Rhaphoneis amphiceros 300 M a r - B r - Tyc R h i z o s o l e n i a hebetata form, semispina 400 Oce-War Stephanopyxis n i p p o n i c a 1400 M a r - Tern-Col >up 5. Species r a r e i n water samples (found i n l e s s than ten samples ) Species Maximum abundance c e l l s / 1 H a b i t a t Achnanthes l o n g i p e s 300 C o s - L i Actinoptychus maculatus 100 Mar Actinoptychus splendens 100 M a r - L i Amphora exigua 400 M a r - C o l Amphora g r a e f f i v a r . minor 100 Mar Amphora l i n e a o l a t a 700 Br Amphora pusio v a r . p a r v u l a 200 Mar-Br A r a c h n o i d i s c u s ehrenberg 200 M a r - L i A s t e r i o n e l l a b l e a k e l e y i 2000 M a r - B r A s t e r i o n e l l a formosa 400 F r < A s t e r i o n e l l a k a r i a n a 4400 N e r - C o l - B o r B a c i l l a r i a p a x i l l i f e r 3500 Cos-Mar-Br B a c t e r i a s t r u m d e l i c a t u l u m 200 Oce-Tem C a l o n e i s b r e v i s v a r . vexans 200 Mar-Br Chaetoceros ceratosporum 400 Ner-Bor Chaetoceros c i n t u s 1200 Ner-Tem Chaetoceros danicus 8000 Ner-Tem Chaetoceros i n g o l f i a n u s 1100 Ner-Tem Chaetoceros simplex 1900 Ner-Tem Chaetoceros s u b t i l i s 1700 Ner-Tem? Chaetoceros t e t r a s t i c h o n 800 Oce-War Cocconeis c l a n d e s t i n a 4 M a r - L i 50 Table VIII (continued). Group 5.Species rare i n water samples (found i n l e s s than ten samples) Species Maximum abundance Habitat abundance c e l l s / 1 Cocconeis decipiens 400 Cocconeis d i s c u l u s 300 Cocconeis p l a c e n t u l a var. k l i n o r a p h i s 400 Cocconeis pellucida 200 Cocconeis scutellum var. parva . 400 Coscinodiscus apiculatus var. ambigua 200 Coscinodiscus curvatulus 200 Coscinodiscus gigas 1200 Coscinodiscus k u e t z i n g i i 300 Coscinodiscus perforatus 200 Coscinodiscus r o t h i i 400 Denticula seminae 1600 Diploneis v e t u l a 200 Epithemia turgida 200 F r a g i l a r i a crotonensis ' 700 F r a g i l a r i a i s l a n d i c a 3200 Grammatophora angulosa 600 Grammatophora maxima 500 Guinardia f l a c c i d a 500 Gyrosigma balticum 200 Gyrosigma t e n u i r o s t r i s 200 Haslea wawrikae 800 Hemiaulus s i n e n s i s 800 Licmophora paradoxa 100 Lithodesmium undulatum 2000 Melosira granulata var. angustiaaima 1900 Melosira i s l a n d i c a subsp. sub a r c t i c a 1400 Mar-Li Mar-Br-Li F r - L i Mar-War Mar-Li Mar Ner-Tem Oce-Ner Ner-Tem Cos-Oce Br Mar-Col Mar-Li Br-Fr Br Ner-Bor Mar-Tem-Li Mar-Li Ner-Cos Mar-Br Mar L i Mar-War Ner-War Mar-Li Ner-Tem Fr F r - L i 51 T a b l e V I I I ( c o n t i n u e d ) . Group 5.Species r a r e i n water samples (found i n l e s s than ten samples) Species Maximum abundance H a b i t a t c e l l s / 1 M e l o s i r a i s l a n d i c a subsp. h e l v e t i c a 1600 F r M e l o s i r a m o n i l i f o r m i s 800 Br M e l o s i r a nummuloides 200 M a r - E s t - L i N a v i c u l a d i r u p t a 200 C o s - M a r - L i N a v i c u l a g i b b u l a v a r . e l l i p t i c a 200 M a r - L i N a v i c u l a g l a c i a l i s 200 M a r - L i N a v i c u l a l a t i s s i m a 200 M a r - L i N a v i c u l a l y r a 400 M a r - L i N a v i c u l a p a l p e b r a l i s 800 M a r - L i N a v i c u l a rhynchocephala 200 B r - F r N i t z s c h i a p a n d u r i f o r m i s . 200 C o s - L i - T y c ? N i t z s c h i a v e r m i c u l a r i s 200 F r N i t z s c h i a s o c i a l i s 100 Mar-Br Plagiogramma v a n h e u r c k i i 4700 Ner-War Pleurosigma acutum 200 Mar Pleurosigma angulatum 200 Br Pleurosigma elongatum 300 M a r - B r Pleurosigma longum 200 M a r - C o l Rhaphoneis s u r i r e l l a 300 Cos-Tyc R h l z o s o l e n i a a l a t a 800 Oce-Tem R h i z o s o l e n i a c a l c a r - a v i s 200 Oce-War R h l z o s o l e n i a f r a g i l i s s i m a 3900 Ner-Bor Rhoicosphenia c u r v a t a 700 Br S t r i a t e l l a d e l i c a t u l a 700 M a r - L i - T y c ? S u r i r e l l a intermedia 200 M a r - L i Synedra k e r g u e l e n s i s 200 N e r - C o l Synedra ulna var.amphirhynchus 500 F r T a b e l l a r i a f e n e s t r a t a v a r . a s t e r i o n e l l o i d e s 1000 F r - B r ? T a b e l l a r i a f e n e s t r a t a 400 F r - L i Table V I I I ( c o n t i n u e d ) . Group 6.Species found o n l y on s l i d e prepared from net m a t e r i a l Species Frequency H a b i t a t Achnanthes l a n c e o l a t a VR F r A c t i n o c y c l u s s u b t i l i s VR Mar^Tem-War Asteromphalus h e p t a c t i s VR Cos-Oce A u l a c o d i s c u s k i t t o n i i VR Ner B i d d u l p h i a a n t e d i l u v i a n u s R M a r - L i B i d d u l p h i a dubia VR Ner^War B i d d u l p h i a s p . A VR ? C a l o n e i s l a t i u s c u l a VR F r Campylodiscus l a t u s VR M a r - L i Campylodiscus l imbatus VR M a r - L i Campylodiscus t h u r e t t i i VR M a r - L i Cocconeis ornata VR M a r - L i Cocconeis pseudomarginata VR M a r - L i C o s c i n o d i s c u s m a r g i n a t o - l i n e a t u s V R Mar C o s c i n o d i s c u s normanii VR M a r - L i C y c l o t e l l a comta R F r Cymbella aspera . V R F r Cymbella c i s t u l a V R F r D i p l o n e i s l i n e a t a V R M a r - L i F r u s t u l i a rhomboides V R F r Gyrosigma f a s c i o l a v a r . arcuatum V R Mar Gyrosigma s c a l p r o i d e s v a r . s c a l p r o i d e s V R Fr? Gyrosigma s t r i g i l i s V R Br Gyrosigma sp. A V R Hantzschia v i r g a t a v a r . g r a c i l i s VR M a r - L i Haslea gigantea V R Mar-War Hyalodiscus s u b t i l i s C N e r - C o l Isthmia nervosa R Mar-Tyc Licmophora e h r e n b e r g i i V R M a r - L i M a s t o g l o i a ovata V R Mar-War T a b l e V I I I ( c o n t i n u e d ) . Group 6 .Species found o n l y on s l i d e s prepared from net m a t e r i a l Species Frequency H a b i t a t M e l o s i r a s o l VR Mar M e l o s i r a v a r i a n c e R F r N a v i c u l a h e n n e d y i i VR M a r - L i N a v i c u l a l y r a form, denudata VR Mar N a v i c u l a tenuis R M a r - L i ? N a v i c u l a v i r u d u l a R B r - F r N i t z s c h i a a n g u l a r i s R Mar N i t z s c h i a i n s i g n i s v a r . i n s i g n i s VR Mar N i t z s c h i a i n t e r r u p t e s t r i a t a VR Mar-War • N i t z s c h i a pandurifomis v a r . minor VR M a r - L i P i n n u l a r i a legumen VR F r P i n n u l a r i a t r a n s v e r s a VR F r P l a n k t o n i e l l a s o l VR Oce-War Pleurosigma formosum v a r . l o n g i s s i m a VR Mar Pleurosigma nubecula VR Mar Rhabdonema a d r i a t i c u m VR M a r - L i Rhabdonema arcuatum . C M a r - L i R h i z o s o l e n i a a l a t a form, c u r v i r o s t r i s R Oce Rhopalodia gibba v a r . v e n t r i c o s a VR B r - F r S u r i r e l l a robusta VR . F r Synedra acus R F r Synedra i s a b e l a e v a r . i s a b e l a e VR F r T a b e l l a r i a f e n e s t r a t a v a r . intermedia VR F r T h a l a s s i o s i r a e l s a y e d i i VR Ner? T r a c h y n e i s aspera VR M a r - L i Trigonum a r c t i c u m C M a r - L i Trigonum sp. A R M a r - L i ? T r o p i d o n e i s l e p i d o p t e r a VR M a r - L i 54 Skeletpnema costatum^ Diatoms i n group -V are a l l marine p l a n k t o n i c diatoms except f o r M e l o s i r a i t a l i c a which i s a f r e s h water and marine l i t t o r a l s p e c i e s . Members of the genus Chaetoceros were found as the major component of t h i s group. F i f t e e n marine p l a n k t o n i c diatoms(Table VIII-2) i n group 2 were a l s o abundant and frequent i n the water samples, but they were r e s t r i c t e d to only one or two seasons. The genera Qhaetoceros and T h a l a s s i o s i r a were the major p o p u l a t i o n s of t h i s group. Group 3 i n c l u d e s the taxa t h a t were frequent i n the samples, but had a maximum abundance•of l e s s than 5000 c e l l s per l i t e r . Most s p e c i e s of t h i s group are marine s o l i t a r y s p e c i e s . S p e c i e s i n group 4(Table VIII) i n c l u d e 13 marine s p e c i e s with 2 l i t t o r a l s p e c i e s . They are i n the same category as group 3, but t h e i r occurrence was r e s t r i c t e d t o one or two seasons. S p e c i e s i n group 5 (Table VIII) were r e l a t i v e l y r a r e i n the water samples and were found i n l e s s than ten samples. Seventy-eight taxa of t h i s group are marine p l a n k t o n i c and marine l i t t o r a l forms , but i t a l s o i n c l u d e s brackish-water and fresh-water forms. Group 6 c o n s i s t s of 58 s p e c i e s which were found only on s l i d e s prepared from net samples. Most of them were rare i n the s l i d e s and l i t t o r a l forms were the major components. Regression j^naly.ses The r e s u l t s of the m u l t i p l e r e g r e s s i o n a n a l y s i s of the t o t a l s t anding crop of the diatom communities are summarized i n Tables IX - XI. The r e g r e s s i o n r e s u l t s f o r a r b i t r a r i l y s e l e c t e d s p e c i e s of p l a n k t o n i c diatoms which were most f r e g u e n t and abundant are summarized i n Table XII. These t a b l e s i n c l u d e o n l y 55 the v a r i a b l e s which were found t o be s t a t i s t i c a l l y s i g n i f i c a n t at the 95% confidence l e v e l . In Table IX, the c o e f f i c i e n t of d e t e r m i n a t i o n , 2 2 , g i v e s the p r o p o r t i o n of the t o t a l v a r i a t i o n i n the dependent v a r i a b l e , y ( t o t a l s t anding c r o p i n t h i s case) t h a t i s accounted f o r by the f i t t e d r e g r e s s i o n . The t o t a l F-values t e s t showed whether or not any of the c o e f f i c i e n t s of the s i g n i f i c a n t v a r i a b l e s are z e r o , so t h a t the p r o b a b i l i t y of the o v e r a l l model can be determined. The r e g r e s s i o n ' c o e f f i c i e n t expresses how much y would change f o r a u n i t change of an independent v a r i a b l e and expresses only p a r t of the dependence r e l a t i o n s h i p . The p a r t i a l F - v a l u e s i n the t a b l e s are a t e s t of whether t h a t v a r i a b l e e x p l a i n s a s i g n i f i c a n t amount of v a r i a t i o n i n the counts. The purpose of t h i s t e s t i s to show whether the c o e f f i c i e n t of t h a t v a r i a b l e i s s i g n i f i c a n t l y d i f f e r e n t from zero. These values are a l l ' r e a s o n a b l e c o n s i d e r i n g the i n h e r e n t v a r i a t i o n i n the data. However, the r e g r e s s i o n c o e f f i c i e n t can be m isleading when comparing the e f f e c t s of independent v a r i a b l e s on diatom standing crop, because d i f f e r e n t v a r i a b l e s are u s u a l l y measured i n d i f f e r e n t u n i t s and have d i f f e r e n t v a r i a n c e s . T h i s problem can be s o l v e d by c a l c u l a t i n g the normalized r e g r e s s i o n c o e f f i c i e n t s . The normalized r e g r e s s i o n c o e f f i c i e n t s are the r e g r e s s i o n c o e f f i c i e n t s which would be , produced i f the v a r i a b l e s were f i r s t transformed to have u n i t v a r i a n c e . Thus the l a r g e r the normalized c o e f f i c i e n t , the more s i g n i f i c a n t the c o n t r i b u t i o n t h a t the v a r i a b l e makes to the T a b l e IX. R e l a t i o n s h i p s between t o t a l s tanding crop and environmental parameters Sample s i z e : 300 2 C o e f f i c i e n t of determination (R ) : 0.3415 Standard e r r o r of e s t i m a t e : 0.6814 F ( 9 , 290): 16.696 P r o b a b i l i t y : 0.0000 P a r t i a l Normalized % V a r i a b l e * C o e f f i c i e n t F P r o b a b i l i t y Coef. Importance Winter -0.6577 36.95 0.0000 -0.3187 17.94 F a l l -0.5743 27.42 0.0000 -0.2783 15.13 1 m 0.4989 26.22 0.0000 0.2617 14.23 S t a t i o n 1 -0.3103 21.00 0.0000 -0.2422 13.17 s i o 3 -0.0129 18.35 0.0000 -0.2198 11.95 S t a t i o n 2 -0.2451 8.27 0.0044 -0.1504 8.18 N H 3 0.1965 6.49 0.0110 0.1335 7.26 S t a t i o n 5 -0.2451 5.12 0.0231 -0.1187 6.45 25 m 0.2206 5.23 0.0218 0.1157 6.29 * S i g n i f i c a n t v a r i a b l e s at 95% l e v e l Normalized c q e f f i c i e n t of X i % Importance = x 100 Sum of Normalized c o e f f i c i e n t s 57 T a b l e X . R e l a t i o n s h i p between t o t a l standing crop and environmental parameters i n each month d u r i n g May 1972 - J u l y 1973 Month R 2 T o t a l P V a r i a b l e P a r t i a l P C o r r e l a t i o n % Importance 1972 May 0.3808 0.0168 St. 3 0.0112 + 55.97 St. 4 0.0382 + 44.03 June 0.7493 0.0001 St. 5 sio 3 0.0001 0.0020 - ' 45.33 31.34 Temp. 0.0101 + 23.33 J u l y 0.5626 0.0009 St. 3 0.0026 - 53.57 1 m 0.0069 + 46.43 Aug. 0.8897 0.0000 Temp. 0.0000 + 59.16 St. 2 0.0001 29.02 St. 5 0.0402 + 11.82 Sept. 0.2432 0.0259 St. 1 0.0259 - 100.00 Oct. 0.6901 0.0001 P 0 4 0.0000 - 67.57 St. 2 0.0104 - 32.43 Nov. 0.7683 0.0000 Temp. 0.0000 - 51.95 S a l i n i t y 0.0000 - 48.05 Dec. 0.3589 0.0052 N0 3 0.0052 - 100.00 1973 J a n . 0.8242 0.0000 S t . 1 0.0000 - 48.28 Temp. 0.0028 - 30.39 1 m 0.0209 — 21.33 58 T a b l e X (continued), Month 7 T o t a l R P P a r t i a l V a r i a b l e P C o r r e l a t i o n % Importance Feb. No s i g n i f i c a n t v a r i a b l e found at the i n d i c a t e d % l e v e l Mar. 0.7873 0.0000 N 0 2 0.0007 + 46.37 N 0 3 0.0032 - 31.96 1 m 0.0376 - 21.66 A p r . 0.4847 0.0007 P ° 4 0.0007 100.00 May 0.8205 0.0000 s i o 3 0.0000 - 37.41 St . 2 0.0001 - 32.25 St. 1 0.0002 - 30.34 June 0.8977 0.0000 s i o 3 0.0000 - 29.11 St . 2 0.0000 - 27.23 St . 1 0.0000 - 25.94 N 0 2 0.0014 - 17.71 J u l y 0.7733 0.0000 S t . 1 ' 0.0000 - 67. 75 N 0 2 0.0033 - 32.25 P: p r o b a b i l i t y a t 5% l e v e l 59 . R e l a t i o n s h i p between t o t a l s tanding crop and environmental parameters at each s t a t i o n S t a t i o n R 2 T o t a l P V a r i a b l e P a r t i a l P C o r r e l a t i o n % Importance St. 1 0.3753 0.0000 s i o 3 0.0004 - 44.87 1 m 0.0302 + 27.58 75 m 0.0277 - 27.55 St . 2 0.3283 0.0001 S a l i n i t y 0.0003 • - 44.51 s i o 3 0.0037 - 30.58 N H 3 0.0321 - 24.91 St-. 3 0.2863 0.0003 Winter 0.0005 - 40.03 F a l l 0.0029 - 35.60 N H 3 0.0310 + 24.37 St . 4 0.6832 0.0000 F a l l 0.0000 - 28.63 Temp. 0.0000 + 24.93 N 0 2 0.0000 + 21.26 s i o 3 0.0000 - 16.98 N 0 3 ' 0.0336 + 8.22 St . 5 0.3383 0.0000 S p r i n g 0.0003 + 39.53 Temp. 0.0021 + 33.09 Summer . 0.0109 + 27.38 60 r e g r e s s i o n model. The % importance of each s i g n i f i c a n t v a r i a b l e i s c a l c u l a t e d from the normalized r e g r e s s i o n c o e f f i c i e n t s . The m u l t i p l e r e g r e s s i o n a n a l y s i s of the t o t a l s t a n d i n g crop of diatoms on a l l environmental parameters measured, as w e l l as l o c a t i o n and s e a s o n a l parameters (Table IX), shows t h a t the l o c a t i o n or season was r e l a t e d t o the standing crop more c l o s e l y than the measured p h y s i c a l and n u t r i e n t parameters, of which s i l i c a t e and ammonia were the only s i g n i f i c a n t v a r i a b l e s i n r e l a t i o n to the change i n t o t a l s t a n d i n g crop. The B 2 value of t h i s model i s 0.34 which i n d i c a t e s about 34% of v a r i a n c e i n the standing crop may be e x p l a i n e d by the 9 independent v a r i a b l e s , while 66% of the variance i n the s t a n d i n g crop remains unexplained by the p o t e n t i a l independent v a r i a b l e s and i s presumably due to some unmeasured independent v a r i a b l e s such as l i g h t i n t e n s i t y , vitamin B12, zooplankton grazing and so on. C a t t e l l ( 1 9 6 9 ) i n h i s r e g r e s s i o n analyses found t h a t v i t a m i n B12 was a s i g n i f i c a n t f a c t o r i n determining the s i z e of the d i n o f l a g e l l a t e community during s p r i n g i n the S t r a i t of Georgia, Of the 9 v a r i a b l e s season and l o c a t i o n f a c t o r s such as winter, f a l l , and 1 m were h i g h l y s i g n i f i c a n t . S t a t i o n 1 was the next s i g n i f i c a n t , while the other t h r e e such as S t a t i o n 2, S t a t i o n 5 and 25 m showed r e l a t i v e l y low s i g n i f i c a n c e . For the n u t r i e n t f a c t o r s , s i l i c a t e was h i g h l y s i g n i f i c a n t , but ammonia showed low s i g n i f i c a n c e . The m u l t i p l e r e g r e s s i o n a n a l y s e s of each month d u r i n g May 1972-July 1973(Table X) i n d i c a t e s t h a t there were marked 61 temporal changes i n the independent v a r i a b l e s t h a t were s i g n i f i c a n t l y a s s o c i a t e d with the t o t a l standing crop of diatoms. Again, the l o c a t i o n s were important i n d e t e r m i n i n g the change of the s t a n d i n g crop except i n December 197 2 and i n the e a r l y s p r i n g months of 1973 when n u t r i e n t elements were important f a c t o r s . In February 1973 no s i g n i f i c a n t independent v a r i a b l e was found at the 95% l e v e l . S i l i c a t e was the most f r e q u e n t l y s i g n i f i c a n t v a r i a b l e among those p h y s i c o - c h e m i c a l parameters measured and u s u a l l y proved to be n e g a t i v e l y c o r r e l a t e d with s t a n d i n g crop. Phosphorus was the only s i g n i f i c a n t v a r i a b l e i n A p r i l 1973 and n i t r o g e n was the most important f a c t o r i n December 1972 and i n March 1973. There was a s i g n i f i c a n t p o s i t i v e r e g r e s s i o n with temperature and the standing crop of diatoms i n June and August 1972, while a s i g n i f i c a n t negative r e g r e s s i o n was noted between the two v a r i a b l e s i n November 1972 and i n January 1973. S a l i n i t y was the only s i g n i f i c a n t v a r i a b l e i n 'November 1972 when i t proved to be n e g a t i v e l y c o r r e l a t e d with the t o t a l s t a n d i n g crop of diatoms. The r e s u l t s of m u l t i p l e r e g r e s s i o n s of the s t a n d i n g crop of diatom s p e c i e s on 5 s t a t i o n s (Table XI) a l s o show that t h e r e was c o n s i d e r a b l e change i n s i g n i f i c a n t independent v a r i a b l e s with the diatom s p e c i e s . At S t a t i o n 1 s i l i c a t e and depth elements were s i g n i f i c a n t l y c o r r e l a t e d with the diatom abundance. S u r p r i s i n g l y , no l o c a t i o n or season was found to be a s i g n i f i c a n t v a r i a b l e at S t a t i o n 2, while s a l i n i t y , s i l i c a t e and ammonia showed a s i g n i f i c a n t negative r e l a t i o n s h i p with the diatoms. Winter, f a l l (as season f a c t o r s ) and ammonia (as a 62 chemical f a c t o r ) were important f a c t o r s a t S t a t i o n 3. . At S t a t i o n 4 the n u t r i t i o n a l elements such as n i t r a t e , n i t r i t e and s i l i c a t e as w e l l as temperature were important f a c t o r s i n the v a r i a t i o n of diatoms. F a l l (as a season f a c t o r ) was a l s o s i g n i f i c a n t a t t h i s s t a t i o n . There was a s i g n i f i c a n t p o s i t i v e r e g r e s s i o n between dependent v a r i a b l e s and independent v a r i a b l e s such as s p r i n g , temperature and summer. The m u l t i p l e r e g r e s s i o n a n a l y ses of 34 s e l e c t e d i n d i v i d u a l diatom s p e c i e s based upon the environmental parameters are summarized i n Table X I I . These data show that diatom p o p u l a t i o n changes were accompanied by co n s i d e r a b l e - v a r i a t i o n s i n the independent " v a r i a b l e s . As would be expected the occurrence of Skeletonema costatum which i s u s u a l l y a dominant diatom during s p r i n g and summer, demonstrated a s i g n i f i c a n t r e l a t i o n s h i p with seasons and depth, but was not dependent upon any of the phys i c o - c h e m i c a l parameters measured. Thaiassionema H i i z s c h i o i d e s which i s one of the commonest s p e c i e s i n the area, showed s i g n i f i c a n t r e l a t i o n s h i p s with' summer and n u t r i e n t f a c t o r s as w e l l as l o c a t i o n f a c t o r s . P a r a l i a s u l c a t a s h o w e d a s i g n i f i c a n t r e l a t i o n s h i p with l o c a t i o n f a c t o r s , e s p e c i a l l y with depths, as well as f a l l (as a seasonal f a c t o r ) . T h a l a s s i o s i r a g a c i f i c a which was u s u a l l y one of the major p o p u l a t i o n s and sometimes the dominant s p e c i e s i n s p r i n g bloom rev e a l e d a h i g h l y s i g n i f i c a n t r e l a t i o n s h i p between i t and s p r i n g as a season f a c t o r and was a l s o c l o s e l y r e l a t e d with s i l i c a t e . The s p e c i e s which- showed 1 a s i g n i f i c a n t r e l a t i o n s h i p - with summer were Chaetoceros d e c i p i e n s , Ch. r a d i c a n s x Ch^ s i m i 1 1 s x Corethron Table X I I . R e l a t i o n s h i p between p l a n k t o n i c diatom species and environmental parameters Species R* T o t a l P a r t i a l % P V a r i a b l e P C o r r e l a t i o n Importance A s t e r i o n e l l a  g l a c i a l i s B i d d u l p h i a  l o n g i c r u r i s C e r a t a u l i n a  p e l a g i c a Chaetoceros a f f i n i s Chaetoceros cpmpressus Chaetoceros Chaetoceros d e b i l i s 0.5750 0.0000 Winter 0.2149 0.284 1 m 0.1700 0.310 Summer 0.4597 0.0000 Temp. Summer Spring 0.4530 0.0000 PO 4 Spring c o n c a v i c o r n i s 0.0724 0.0093 Spring 0.4081 0.0000 SiO. 1 m Summer St. 1 0.0000 0.0284 0.0310 0.0000 0.0006 0.0033 O.COOO 0.0125 0.0093 0.0000 0.0002 0.0003 0.0253 + + + + + + 100.00 100.00 100.00 48.23 28. 38 23.39 71.49 28.51 100.00 34.54 26.48 24.46 14.58 Table X I I (continued). Species T o t a l P a r t i a l P V a r i a b l e P % C o r r e l a t i o n Importance Chaetoceros  decipiens Chaetoceros  didymus Chaetoceros d i f f i c i l i s Chaetoceros radicans 0.2249 0.0004 Summer 1 m 0.3118 0.0000 1 m s i o 3 0.7696 0.0000 1 ro. F a l l St. 1 N0 3 25 m St. 2 S a l i n i t y N0 2 0.3201 0.0000 Summer 75 m 0.0017 0.0084 0.0002 0.0006 0.0000 0.0000 0.0000 0.0000 0.0001 0.0002 0.0168 0.0122 0.0000 0.0337 + + + + + + + 55.00 45.00 52.11 47.89 22.98 14.99 13.46 13.14 10.57 10.41 7.32 7.03 71.92 28.08 Table XII (continued). Species Chaetoceros s i m i l i s R 0.3770 Total P 0.0000 Variable Summer St. 1 N0 3 Temp. St. 2 Chaetoceros  s o c i a l i s Corethron  criophilum 0.3843 0.4906 0.0000 1 m 0.0000 PO 4 Temp. St. 3 St. 1 s i o 3 Summer 75 m Coscinodicus  centralis var. p a c i f i c a 0.2829 0.0022 St. 3 Summer P a r t i a l % P Correlation Importance 0.0004 + 23.62 0.0007 - 23.03 0.0062 - 20.88 0.0189 + 18.21 0.0270 - 14.26 0.0000 + 100.00 0.0004 - 20.11 0.0005 - 18.98 0.0005 + 15.98 0.0018 + 14.15 0.0028 - 12.89 0.0259 - 9.50 0.0421 - 8.39 0.0134 - 51.97 0.0212 + 48.03 Table XII (continued). Species R Total P Variable P a r t i a l % P Correlation Importance Coscinodiscus lineatus Cylindrotheca closterium Ditylium b r i g h t w e l l i i Eucampia zodiacus 0.1812 0.2381 0.5035 0.4437 0.0038 0.0000 0.0000 St. 1 Summer NH 3 Summer N0 3 50 m Temp. F a l l P 04 St. 1 0.0002 PO 4 St. 4 St. 5 0.0086 0.0232 0.0459 0.0020 0.0029 0.0498 0.0000 0.0000 0.0104 0.0429 0.0001 0.0040 0.0146 + + + + + 38.59 32.98 30.53 38.03 37.80 24.17 37.55 30.07 15.77 12.91 45.51 30.60 25.26 Table XII (continued). Species Total P Variable P a r t i a l .% P Correlation Importance Leptocylindrus danicus 0.5385 0.0000 NO Nitzschia d e l i c a t u l a Nitzschia  longissima 0.3927 0.4363 0.0000 0.0000 3 Temp. St. 4 75 m Winter F a l l 75 m s i o 3 P 04 St. 1 N0 3 50 m P 04 Winter F a l l NH„ 0. 0001 0.0061 0.0012 0.0050 o.oboo 0.0000 0.0003 0.0005 0.0145 0.0225 0.0424 0.0468 0.0000 0.0000 0.0000 0.0000 + 36.59 24.45 20.97 18.15 22.98 19.86 14.26 13.05 9.15 7. 74 7.50 7.37 24.30 19.94 14.86 14. 66 Table XII (continued). 2 Total P a r t i a l % Species R P Variable P Correlation Importance Nitzschia  pungens Nitzschia seriata P a r a l i a sulcata 0.2611 0.0012 0.3784 0.0000 0.3991 0.0000 St. 2 St. 1 s i o 3 P°4 s i o 3 Temp. P 0 4 75 m 50 m s i o 3 F a l l St. 1 St. 2 75 m 0.0009 0.0023 0.0288 0.0100 0.0362 0.0000 0.0032 0.0023 0.0403 0.0411 0.0000 0.0000 0.0000 0.0120 + + + 10.08 9.29 6.87 55.63 44.37 37.48 22.24 17.74 11.55 11.00 36.21 32.31 16.85 10. 71 Table XII (continued). Species R Total P a r t i a l % P Variable P Correlation Importance Rhizosolenia d e l i c a t u l a 0.5294 0.0000 SiO Rhizosolenia  setigera Schroederella d e l i c a t u l a Skeletonema costatum 0.2911 0.4256 0.3761 Thalassionema nitzschioides 0.3461 0.0000 0.0000 0.0000 3 Summer 0.0136 NH. Summer s i o 3 75 m Winter F a l l 1 m St. 3 St. 4 25 m Summer SiO„ 0.0000 0.0006 0.0389 0.0136 0.0000 0.0032 0.0060 0.0000 0.0000 0.0000 0.0005 0.0039 0.0078 0.0000 0.0000 + + + + + + + 46.54 34.36 19.10 100.00 47.38 '27.40 25.22 26.09 23.23 17.11 13.06 10.58 9.94 32.31 19.69 Table XII (continued). Species R Total P Variable P a r t i a l % P Correlation Importance Thalassiosira eccentricus 0.2159 0.0003 Thalassiosira nordenskioeldii 0.3733 0.0000 Thalassiosira  p a c i f i c a Thalassiosira rotula 0.5295 0.0000 0.3079 0.0000 Temp. St. 4 St. 5 S i 0 3 NH3 25 m 1 m Temp. 25 m S i 0 3 Spring S i 0 3 Spring S i 0 3 P 04 St. 5 0.0010 0.0011 0.0015 0.0027 0.0079 0.0093 0.0000 0.0130 0.0032 0.0290 0.0470 0.0000 0.0041 0.0000 0.0001 0.0282 + + + + + + + + 16.94 15.69 15. 37 36.60 32.09 31. 31 40.23 18.29 17.05 12.29 12,14 70.50 29.50 42.09 38.22 19.69 71 c r i o p h i l u m t -Coscinodiscus • c e n t r a l i s var. o a c i f i c a A l i n e a t u s x C YlJ-nd r o t hec a • c l os t e r i u rof R h i z o s o l e n i a d e l i c a t u l a ^ . Sehr o e d e r e l l a d§licatula x and Thalassionema n i t s c h i o i d e s ^ Of these s p e c i e s crio£hilum and Cose., l i n e a t u s showed a negative r e l a t i o n s h i p between themselves and summer. Th i s f i n d i n g i s supported by the f i e l d o b s e r v a t i o n t h a t Ci. c r i o ^ h i l u m was predominant i n s p r i n g and f a l l , and t h a t Cose., l i n e a t u s uas u s u a l l y absent i n summer. Analyses' o f - Chaetoceros £§£i£i§U§x Chj. didimus J L C h i d i f f i c i l i s x Ch.; s o c i a l i s , Cose;, l i n e a t u s t Si^eigtonema costatum and T h a l a s s i o s i r a n g r d e n s k i o e l d i i r e v e a l e d a s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p between themselves and 1 m l e v e l while Chaetoceros £llisdrus x ' Cy_lindrotheca c-lgs t e r i u m x L e p t o c y l i n d r u s d a n i c u s x ' N i t z s c h i a d e l i c a t u l a , N^ . ser i at a and S c h r o e d e r e l l a d e l i c a t u l a showed a s i g n i f i c a n t n e gative r e l a t i o n s h i p between themselves and the 75 m or 50 m l e v e l . Analyses of T h a l a s s i o s i r a n g r d e n s k i o e l d i i and N i t z s c h i a s e r i a t a r e v e a l e d a s i g n i f i c a n t negative r e l a t i o n s h i p between themselves and temperature, while i n the case of Thalassignema n i t z s c h i o i d e s , le£tocxlindrus danicus and Bity_lum b r i a h t w e l l i i t here was a s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p with temperature. The occurrence of most other p l a n k t o n i c diatom s p e c i e s demonstrated a s i g n i f i c a n t r e l a t i o n s h i p with one or more environmental parameters. I n g e n e r a l , the r e s u l t s of the m u l t i p l e r e g r e s s i o n a n a l y s e s show s i g n i f i c a n t but v a r i a b l e r e l a t i o n s h i p s e x i s t i n g between p l a n k t o n i c diatoms and the p hysico-chemical f a c t o r s measured, as 72 w e l l as with seasons and l o c a t i o n s f a c t o r s , and are i n agreement with p r e v i o u s measurements i n the study area as r e p o r t e d i n the l i t e r a t u r e ; Recurrent Species Group. A n a l y s i s In order to determine which diatom s p e c i e s were more f r e q u e n t l y found t o g e t h e r a r e c u r r e n t group a n a l y s i s (Fager, 1957; Fager and McGowan, 1963) was run. The a n a l y s i s was a p p l i e d to 116 p l a n k t o n i c s p e c i e s which occurred two or more times. The r e s u l t showed t h a t o n l y 11 s p e c i e s had s i g n i f i c a n t a f f i n i t i e s with o t h e r s p e c i e s ( w i t h I.A. = 0.5) and could not form any u s e f u l groups, I t seemed c l e a r t h a t i n many cases the frequency of occurrence of diatom s p e c i e s w i t h i n 10 ml sample was t o o low to give s i g n i f i c a n t groupings. Secondly, a l l samples wit h i n the 75m water column were lumped at each s t a t i o n f o r o b t a i n i n g a f f i n i t i e s between s p e c i e s . With the lumped data e i g h t r e c u r r e n t s p e c i e s groups were formed. However, i t i s p o s s i b l e t h a t one s p e c i e s may have been at a s p e c i f i c depth i n one s e t of c o n d i t i o n s and another s p e c i e s at the other depth. In t h i s case the two s p e c i e s would not be a s s o c i a t e d . F i n a l l y , the f i r s t program was rerun with I.A.=0.33 i n d i c a t i n g s i g n i f i c a n t a f f i n i t y . T h i s kind of m o d i f i c a t i o n f o r the a n a l y s i s has been used by L i e and K e l l e y (1970) the r e c u r r e n t s p e c i e s qroups which r e s u l t e d from t h i s a n a l y s i s are presented i n Table X I I I . 73 Table X I I I . Species composition of r e c u r r e n t groups (species l i s t e d i n order of descending abundance) Group I - ten species + two a s s o c i a t e s Skeletonema costatum  N i t z s c h i a d e l i c a t u l a  T h a l a s s i o s i r a r o t u l a  Thalassionema n i t z s c h i o i d e s  N i t z s c h i a l o n g i s s i m a  R h i z o s o l e n i a d e l i c a t u l a  Chaetoceros a f f i n i s  Chaetoceros radicans  Chaetoceros s i m i l i s  Chaetoceros didymus a s s o c i a t e d : S c h r o e d e r e l l a d e l i c a t u l a  P a r a l i a s u l c a t a Group I I - s i x species + one a s s o c i a t e Chaetoceros d e b i l i s  T h a l a s s i o s i r a n o r d e n s k i o e l d i i  N i t z s c h i a s e r i a t a  Chaetoceros compressus  Chaetoceros diadema  Chaetoceros d e c i p i e n s a s s o c i a t e d : Chaetoceros c o n c a v i c o r n i s Group I I I - f i v e species + two a s s o c i a t e s Chaetoceros s o c i a l i s  T h a l a s s i o s i r a p a c i f i c a  T h a l a s s i o s i r a a e s t i v a l i s  T h a l a s s i o s i r a polychorda Chaetoceros l a c i n i o s u s .1 74 Table X I I I . (continued) Group I I I a s s o c i a t e d : C y l i n d r o t h e c a c l o s t e r i u m  T h a l a s s i o s i r a sp. B Group IV - four species + one a s s o c i a t e Corethron c r i o p h i l u m  T h a l a s s i o s i r a e c c e n t r i c u s  Coscinodiscus l i n e a t u s  Coscinodiscua r a d i a t u s a s s o c i a t e d : Coscinodiscus c e n t r a l i s var. p a c i f i c a Group V - s i x species + two a s s o c i a t e s • Ditylum b r i g h t w e l l i i  Chaetoceros d i f f i c i l i s T h a l a s s i o s i r a d e c i p i e n s  Chaetoceros c o n s t r i c t u s  Chaetoceros v a n h e u r c k i i  N i t z s c h i a pungens a s s o c i a t e d : Chaetoceros b r e v i s  C e r a t a u l i n a pelagicum 75 DISCUSSION A. The General Seasonal D i s t r i b u t i o n of Standing Crop Some s t u d i e s from c o a s t a l environments have i n d i c a t e d t h a t the s e a s o n a l c y c l e of phytopla.nkto.n- abundance i n a r e g i o n may be i n t e r p r e t e d i n terms of the f l u c t u a t i o n s of a r e l a t i v e l y few e c o l o g i c a l f a c t o r s , and t h a t these f a c t o r s are s i m i l a r i n a wide v a r i e t y of environments (Gran S Braarud, 1935; C o r e l e t t , 1953; Conover, 1956; Holmes, 1956; S t e e l e , 1958; Bursa, 1961; Thayer, 1971). With the a i d of the r e s u l t s of such s t u d i e s , the present data can be i n t e r p r e t e d i n terms of a probable seasonal c y c l e . There i s an annual c y c l e of phytoplankton p r o d u c t i o n and sta n d i n g crop which has been observed i n a wide range of h a b i t a t s . T h i s c y c l e i s c h a r a c t e r i z e d by a r a p i d i n c r e a s e during the s p r i n g and o f t e n a s m a l l e r i n c r e a s e i n the f a l l , and by minimum standing c r o p s of diatoms i n l a t e summer(Gran, 1932; S t r i c k l a n d , 1960; Anderson and Banse, 1961). Of primary importance to t h i s c y c l e are n u t r i e n t c o n c e n t r a t i o n s and l i g h t i n t e n s i t y ; the a v a i l a b i l i t y and e f f e c t of both i s d i r e c t l y or i n d i r e c t l y dependent upon the s t r a t i f i c a t i o n of the water column. In most areas, the commencement o f the s p r i n g bloom c o i n c i d e s with the s t a b i l i z a t i o n of the water column. At t h i s time, n u t r i e n t c o n c e n t r a t i o n s i n the s u r f a c e l a y e r s have been i n c r e a s e d by upward mixing of deep n u t r i e n t - r i c h water during the winter, and c o n d i t i o n s are fa v o u r a b l e f o r maximum p r o d u c t i o n of diatoms. The subsequent r a p i d d e c l i n e i n the st a n d i n g crop i s 76 o f t e n a t t r i b u t e d t o g r a z i n g by zooplankton, which bloom i n response to the i n c r e a s e d food supply. The annual c y c l e of s t a n d i n g crop i s accompanied by a succession of s p e c i e s , p r e d i c t a b l e w i t h i n l i m i t s . C h a r a c t e r i s t i c a l l y , diatoms predominate during the s p r i n g and f a l l blooms, and d i n o f l a g e l l a t e s and m i c r o f l a g e l l a t e s d u r i n g the summer. T h i s annual c y c l e of v a r i a t i o n i n environmental parameters and phytoplankton standing crops has been observed i n near shore waters. Parsons(1965) has summarized the p r o d u c t i v i t y and standing crop data c o l l e c t e d a t two c o l d water c o a s t a l areas i n the e a s t e r n P a c i f i c , the S t r a i t of Georgia, and Queen C h a r l o t t e Sound as well as at Weather S t a t i o n P i n the open North Eastern P a c i f i c . Estimates of standing crop were obtained from s u r f a c e c o n c e n t r a t i o n s of c h l o r p h y l l a. In the the S t r a i t of G e o r g i a , a l a r g e v e r n a l i n c r e a s e i n the s t a n d i n g crop occurred i n March, at the commencement of s t r a t i f i c a t i o n . T h i s was f o l l o w e d by a d d i t i o n a l i n c r e a s e s i n A p r i l and May, apparently as a r e s u l t of short p e r i o d s of i n c r e a s e d mixing which r e p l e n i s h e d the n u t r i e n t c o n c e n t r a t i o n s i n the euphotic zone. A s i g n i f i c a n t f a l l i n c r e a s e o c c u r r e d i n some years. The c y c l e observed i n Queen C h a r l o t t e Sound was s i m i l a r . However, a markedly d i f f e r e n t p a t t e r n i n the s t a n d i n g crop was evident a t S t a t i o n P which showed, no s i g n i f i c a n t s e a s o n a l f l u c t u a t i o n s . Observations from the north western edge of the C e n t r a l P a c i f i c have revealed the t y p i c a l bimodal c y c l e of diatom abundances with maxima i n March and October(Motoda and Marumo, 1963). 77 Within the the S t r a i t of Georgia/Juan de Fuca system the annual c y c l e i n the diatom s t a n d i n g crop corresponds with Parsons' g e n e r a l p r o d u c t i v i t y p i c t u r e , at S t a t i o n 1 i n the the S t r a i t of Georgia and at S t a t i o n 3 i n the Boundary Pass, the •spring peaks i n the diatom standing crop probably f o l l o w e d soon a f t e r the s t a b i l i z a t i o n of the water column, i n A p r i l or Hay(Figures 2 and 7 ) . S t r a t i f i c a t i o n of the water column i n c o a s t a l waters u s u a l l y begins e a r l i e r , p o s s i b l y because of d i l u t i o n of s u r f a c e waters by t e r r e s t r i a l run o f f ( T u l l y and Dodimead, 1957; Waldichuk, 1957). The second peak of the diatom standing crop was caused by the i n f u s i o n of r e p l e n i s h e d n u t r i e n t s from the upwelled deeper water, because i n deeper water the n u t r i e n t s are always abundant ( P a c i f i c Oceanographic Group, 1953) and i n f u s e d i n t o the s u r f a c e water by entrainment (Herlinveaux and Giovando, 1969). Breakdown of summer s t r a t i f i c a t i o n begins i n J u l y or August and an i n c r e a s e i n prod u c t i o n i n the f a l l f o l l o w s as l o n g as there i s s u f f i c i e n t l i g h t . The decrease of diatom standing crop i n the winter months proceeds u n t i l maximum v e r t i c a l mixing i s f u l l y developed. In the study area t h i s occurs i n l a t e w i n t e r - e a r l y s p r i n g ( T u l l y and Dodimead, 1957). The maintenance of an i n c r e a s e i n the s t a n d i n g crop of diatoms may depend upon the c o n c e n t r a t i o n s of z o o p l a n k t e r s , p a r t i c u l a r l y at the onset of the bloom. Smayda(1973) showed t h a t g r a z i n g was a major " f a c t o r c a using the d e c l i n e of p l a n k t o n i c diatoms during the s p r i n g bloom i n Narragansett Bay. A s i m i l a r e f f e c t of h e r b i v o r e s upon the f l u c t u a t i o n s of the s t a n d i n g crop 78 of phytoplankton i n the open P a c i f i c has been r e p o r t e d ( P a r s o n s , 1965). The annual c y c l e s of the standing crop of diatoms observed at S t a t i o n 2 o f f the mouth of the Fraser R i v e r , S t a t i o n 4 i n Haro S t r a i t and S t a t i o n 5 i n Juan de Fuca S t r a i t are d i f f e r e n t from those of S t a t i o n s 1 and 3. No t y p i c a l s p r i n g / f a l l peak p a t t e r n was found a t these S t a t i o n s . The second s p r i n g bloom u s u a l l y occurred i n e a r l y summer and t h i s high diatom c o n c e n t r a t i o n was maintained u n t i l the decrease began i n the f a l l . The annual c y c l e of the diatom s t a n d i n g crop at S t a t i o n 2 was l a r g e l y c o n t r o l l e d by the e f f e c t of the F r a s e r River d i s c h a r g e . The summer bloom of diatoms i n the upper l a y e r (1-25 m) of the water column became s t r o n g l y s t r a t i f i e d as i n d i c a t e d by temperature and s a l i n i t y measurements and was maintained u n t i l the s t a b i l i t y of the water broke down i n the f a l l . The sharp decrease(from the previous month) i n the s t a n d i n g crop below the 50 m l e v e l d u r i n g s p r i n g (Figure 8 ) , which was a l s o observed at S t a t i o n .3, was p o s s i b l y caused by l i g h t l i m i t a t i o n and not by n u t r i e n t c o n c e n t r a t i o n , because no l i m i t i n g l e v e l of n u t r i e n t s was found at t h i s time; a l s o a sharp r e d u c t i o n of t o t a l d a i l y r a d i a t i o n was e x a c t l y c o i n c i d e n t with the d e c l i n e (Figure 13). Evidence suggests the annual discharge from the F r a s e r R i v e r u s u a l l y c a r r i e s huge amounts of s i l t , e s p e c i a l l y i n e a r l y summer(Giovando and Tabata, 1970) and that the e f f e c t of s i l t l i m i t s the phytoplankton photosynthesis due to reduced r a d i a t i o n (Takahashi, F u j i and Parsons, 1973). 79 In marked c o n t r a s t to t h i s c y c l e of the s t a n d i n g crop a t S t a t i o n s 1, 2 and 3, the standing crop at S t a t i o n s 4 and 5 shows n e i t h e r c o n s i d e r a b l e seasonal f l u c t u a t i o n s i n f a l l and winter nor c o n s i d e r a b l e d i f f e r e n c e s i n v e r t i c a l v a r i a t i o n s , except at S t a t i o n 5 i n June 1972. The pronounced maximum of s t a n d i n g crop occurs i n e a r l y summer, and t h i s c o i n c i d e s with the s t a b i l i z a t i o n of the water column. That t h i s p e r i o d of sharp decrease i n the s t a n d i n g crop below 25 m at S t a t i o n 5 was not the r e s u l t of l i m i t i n g physico-chemical f a c t o r s may be due to the presence of a l a r g e p o p u l a t i o n of zooplankton at the onset of the bloom(Himmelraan, pers. comm.). The modified annual diatom c y c l e s a t S t a t i o n s 4 and 5 may be e x p l a i n e d by the presence of upwelled subsurface P a c i f i c Ocean water i n Juan de Fuca S t r a i t . The phenomenon of u p w e l l i n g o f f the B r i t i s h Columbia coast i s evident from A p r i l to August (Pickard, 1963). This oceanic water i s g r a d u a l l y mixed with the o v e r l a y i n g warmer, l e s s - s a l i n e waters i n the S t r a i t . T h i s mixing c o n t i n u e s through the f a l l and winter and r e s u l t s i n r e l a t i v e l y low temperatures i n the area. The c o l d oceanic water reached S t a t i o n 4 about two months l a t e r than S t a t i o n 5; t h i s c o i n c i d e s with the v a r i a t i o n i n t h e diatom s t a n d i n g crop between the two S t a t i o n s . That the annual c y c l e of diatom s t a n d i n g crop a t S t a t i o n s 4 and 5 i s r e l a t e d to temperature- i s suggested by the r e s u l t s of m u l t i p l e r e g r e s s i o n analyses at each s t a t i o n which show t h a t there was a s i g n i f i c a n t p o s i t i v e c o r r e l a t i o n between t o t a l s t a n d i n g crop and temperature at both S t a t i o n s . 80 V e r t i c a l D i s t r i b u t i o n The a v a i l a b l e i n f o r m a t i o n on the v e r t i c a l d i s t r i b u t i o n of marine phytoplankton, much of which i s based on the a n a l y s i s of v e r t i c a l p r o f i l e s , suggests t h a t phytoplankton abundance w i t h i n the e u p h o t i c zone i s c h a r a c t e r i s t i c a l l y non-random along v e r t i c a l axes, and o f t e n have pronounced subsurface maxima. Such d i s t r i b u t i o n s have been r e p o r t e d from the A r c t i c ( B u r s a , 1961), Norwegian f j o r d s ( H a s l e , 1954), Indian Ocean (Yentsch, 1965), the Kuroshio Current (Motoda and Marumo, 1963), the C a l i f o r n i a C urrent (Lorenzen, 1966), the C a l i f o r n i a c o a s t a l waters ( S t r i c k l a n d , 1968), and i n the Gulf of Mexico and the A t l a n t i c Ocean(Hobson and Lorenzen, 1972). In c o n t r a s t , Hulbert(1966) found no s i g n i f i c a n t v a r i a t i o n i n abundance o f the phytoplankton of the Sargasso Sea i n the upper 100 meters. He encountered v e r t i c a l s t r a t i f i c a t i o n only i n the diatom p o p u l a t i o n s over the adjacent c o n t i n e n t a l s h e l f and s l o p e , where the water was more h i g h l y s t r a t i f i e d . A d e t a i l e d study i n a f r e s h water lake(Lund, K i p l i n g , and LeCren, 1958) c l e a r l y demonstrated t h a t t h e v e r t i c a l s t r a t i f i c a t i o n o f the diatom A s t e r i o n e l l a sp. depended upon s t a b i l i z a t i o n of the water column. In the presence of v e r t i c a l mixing, o n l y m o t i l e algae maintained v e r t i c a l s t r a t i f i c a t i o n a g a i n s t the randomizing e f f e c t s of t u r b u l e n c e . Many of the r e p o r t s on v e r t i c a l s t r a t i f i c a t i o n of phytoplankton have been based upon measurements o f c h l o r o p h y l l . R e cently, measurements of c h l o r o p h y l l have i n c l u d e d measurements 81 of phaeophytin, a degradation product of c h l o r o p h y l l which has s i m i l a r a b s o r p t i o n and f l u o r e s c e n c e s p e c t r a (Lorenzen, 1966; S t r i c k l a n d , 1968; Eppley, et a l . , 1970). Lorenzen(1966) examined twelve p r o f i l e s of c h l o r o p h y l l and phaeophytin along the west of Baja C a l i f o r n i a . Phaeophytin c o n t r i b u t e d s i g n i f i c a n t amounts to a l l c h l o r o p h y l l maxima l a y e r s which occurred below the thermocline. Lorenzen suggested t h a t deep maxima r e p r e s e n t c o n c e n t r a t i o n s of d e t r i t a l c h l o r o p h y l l produced by zooplankton. I t i s evident t h a t a l a r g e amount of pigment can be found i n the f a e c e s of copepods, much of i t i n the form of phaeopigments, as w e l l as the degraded forms (Moreth and Yentsch, 1970). Yentsch (1965) found a s i g n i f i c a n t i n c r e a s e i n the c o n c e n t r a t i o n of phaeophytin with depth. However, he a l s o observed t h a t there were higher c o n c e n t r a t i o n s of phaeophytin i n phytoplankton c u l t u r e s i n the l a b o r a t o r y which had been exposed to low l i g h t i n t e n s i t i e s , or kept i n the dark. T h i s i n d i c a t e s t h a t high c o n c e n t r a t i o n s of phaeophytin may be a s s o c i a t e d with v i a b l e phytoplankton p o p u l a t i o n s which have sunk below the euphotic zone. During the present study, both the magnitude and p a t t e r n of the f l u c t u a t i o n s i n the diatom standing crop-along the v e r t i c a l a x i s were r e l a t e d t o the presence of a temperature g r a d i e n t i n the water column. Within the homogeneously mixed l a y e r d u r i n g winter o n l y a s m a l l f l u c t u a t i o n i n the v e r t i c a l d i s t r i b u t i o n of diatoms was o b s e r v e d ( F i g u r e s 7-11). Comparing the v e r t i c a l d i s t r i b u t i o n of t o t a l diatom s t a n d i n g crop with v e r t i c a l temperature v a r i a t i o n during winter, i t was found t h a t the 82 homogeneously mixed l a y e r extended to a depth of more than 75 m throughout the e n t i r e study area. At a l l S t a t i o n s , the major diatom p o p u l a t i o n l a y w i t h i n the mixed l a y e r and i t s d i s t r i b u t i o n seemed t o be random. During s p r i n g and summer, however, a seasonal thermocline was present at about 2 5 meters throughout most S t a t i o n s , and o n l y w i t h i n 25 m of the shallow l a y e r was there a s i g n i f i c a n t p o r t i o n of the diatom d e n s i t y (except S t a t i o n 4 i n s p r i n g ) . Species i n t h i s l a y e r had maxima of abundance and t h i s maximum l a y e r i s conspicuous i n the v e r t i c a l p r o f i l e s of the t o t a l s t a n d i n g crop. T h i s stratum was not merely a r e f l e c t i o n of the s t r a t i f i c a t i o n of the dominant s p e c i e s . Below the thermocline the abundances of a l l s p e c i e s a t a S t a t i o n were approximately the same. I t i s doubtless t h a t l i g h t i s one of the most i n f l u e n c i a ! f a c t o r s f o r the l i f e of phytoplankton. The l i g h t i n t e n s i t y at the s u r f a c e v a r i e s with s e v e r a l f a c t o r s such as l a t i t u d e , season; weather and the time of day. The r e l a t i o n between the l i g h t i n t e n s i t y at depths i n the water and the t u r b i d i t y of the water i n d i c a t e s t h a t the extremes* of t u r b i d i t y common to e s t u a r i n e areas, can have a g r e a t e r e f f e c t on l i g h t as a l i m i t i n g f a c t o r than s e a s o n a l changes i n i n t e n s i t y a t the s u r f a c e ( F e r g u s o n , 1972). Although l i g h t was not measured i n the present study, the data of t o t a l d a i l y r a d i a t i o n from the Department of Environment Records(Figures 12 and 13) i n d i c a t e s t h a t seasonal changes are e v i d e n t i n the study area as w e l l . Seasonal f l u c t u a t i o n s of t o t a l d a i l y and monthly r a d i a t i o n both at S t a t i o n 1 and at S t a t i o n 2 were s i m i l a r to each o t h e r (except 607 • • I I I I I I 1 1 1 • 1 1 1 5 6 7 8 9 10 11 1 2 1 2 3 4 5 6 7 1972 197 3 F i g u r e 13. T o t a l d a i l y and monthly mean r a d i a t i o n r e c e i v e d on a h o r i z o n t a l s u r f a c e at The U n i v e r s i t y of B r i t i s h Columbia (from Department of Environment Records, 19 72,1973) 85 i n May and June, 1972), and t h i s p a t t e r n i n the annual c y c l e i s c o i n c i d e n t with t h a t of the observed diatom standing c r o p . In J u l y 1972 (at S t a t i o n 1), the t o t a l d a i l y r a d i a t i o n below 50 m was reduced n e a r l y t o i t s winter l e v e l s as was diatom s t a n d i n g crop ( f i g u r e s 8 and 12) , while the diatom s t a n d i n g crop i n upper l a y e r s (1 m and 50 m) reached t h e i r maximum. In t h i s case, as p r e v i o u l y pointed out, the l i g h t i n the water column below 50 m was appa r e n t l y l i m i t i n g . The depth of the phytoplankton maximum l a y e r has a s i g n i f i c a n c e p r i m a r i l y i n i t s r e l a t i o n s h i p to the depth of the euphotic zone. The lower l i m i t of the euphotic zone may be d e f i n e d by the compensation depth, the depth a t which ph o t o s y n t h e s i s and r e s p i r a t i o n are equal over a twenty-four hour p e r i o d . T h i s i s g e n e r a l l y assumed to be the depth at which the i n t e n s i t y of r a d i a t i o n i s ^ % of t h a t at the surface (Holmes, 1957; Parsons and Takahashi, 1973). Since huge amount of s i l t , e s p e c i a l l y i n summer months, i s u s u a l l y i n c l u d e d i n the f r e s h water d i s c h a r g e , t h i s compensation depth i n the study area v a r i e s markedly with season. The c o n t i n u i t y of the maximum l a y e r along the t r a n s e c t i s e s p e c i a l l y remarkable c o n s i d e r i n g t h a t i t passes v e r t i c a l l y through the seasonal therraocline, and h o r i z o n t a l l y from one environment i n t o ' another, undergoing a complete change i n s p e c i e s composition as i t progresses (see p. 84). Large d i f f e r e n c e s i n the c o n c e n t r a t i o n of diatom p o p u l a t i o n s at s p e c i f i c depths have been encountered i n the 86 present study and t h i s could be due to s p e c i e s c o m p e t i t i o n f o r d i f f e r e n t n u t r i e n t c o n c e n t r a t i o n s as well as l i g h t , because the i n d i v i d u a l diatom s p e c i e s have d i f f e r e n t requirements f o r n u t r i e n t s and so succeed each other as the i n c r e a s i n g p o p u l a t i o n reduces the a v a i l a b l e n u t r i e n t supply(Hutchinson, 1967). For example, the c o n c e n t r a t i o n of n i t r o g e n i n n a t u r a l waters can have an e f f e c t upon c e l l d i v i s i o n r a t e . I t i s most f r e q u e n t l y l i m i t i n g n u t r i e n t i n e s t u a r i e s (Williams, 1973). The c o n c e n t r a t i o n of n i t r a t e - n i t r o g e n , which reduces maximum uptake of t h i s n u t r i e n t by f a c t o r of two, (Ks), has been measured f o r a number of phytoplankton s p e c i e s (e.g. Carpenter G u i l l a r d , 1970; Eppley and Coatsworth, 1968; and Eppley et a l . , 1969) . values of Ks are r e l a t e d t o the ambient n i t r a t e c o n c e n t r a t i o n and may a l s o be c h a r a c t e r i s t i c of a s p e c i e s ' h a b i t a t . Even c l o n e s of the same s p e c i e s i s o l a t e d from d i f f e r e n t waters may show d i f f e r e n t Ks values (Carpenter and G u i l l a r d , 1970). Peterson(1975) developed a model with which he e x p l a i n e d the s o - c a l l e d the "Paradox of Plankton". He b e l i e v e s t h a t an assemblage of c o e x i s t i n g phytoplankton may be l i m i t e d by s e v e r a l n u t r i e n t s and each s p e c i e s p r i n c i p a l l y l i m i t e d by the a v a i l a b i l i t y of a d i f f e r e n t n u t r i e n t . Thus, s p e c i e s s u c c e s s i o n can o c c u r by the p o s s i b i l i t y of an abundant s p e c i e s monopolizing the n u t r i e n t and f o r c i n g a l e s s abundant s p e c i e s to e x t i n c t i o n , e s p e c i a l l y i n shallow waters. F o r Skeletonema costatum d i f f e r e n t • d i s t r i b u t i o n p a t t e r n s were present. The extreme predominance of S.. costatum during a g r e a t e r part of the year may be due t o i t s t o l e r a n c e to the 87 s p e c i a l environmental c o n d i t i o n s : S. • c o s t a turn • has a wide and e x c e p t i o n a l t o l e r a n c e to both temperature and s a l i n i t y (Smayda, 1973) and a l s o has low l i g h t demand (Braarud, 1 975). I t was suggested that s p e c i a l f l o a t i n g p r o p e r t i e s might give t h i s s p e c i e s an advantage compared with other members of the diatom community(Smayda and Boleyn, 1966). Diatoms may remain v i a b l e i n an i n a c t i v e c o n d i t i o n , even i n darkness, f o r long p e r i o d s of time (Miguel, 1892, c i t e d i n Lewin, 1953). Recently, Omebayashi (19.72) r e p o r t e d that f i v e c u l t u r e d diatoms can s u r v i v e f o r 9-25 mo at 5°C i n the dark, but only very few remained a l i v e . Smayda and M i t c h e l l - I n n e s (19 74) found t h a t seven of nine marine p l a n k t o n i c diatom s p e c i e s used were v i a b l e f o r 90 d at 15° C i n the dark and t h a t Skeletonema costatum s u r v i v e d f o r 44 d i n the dark and i t s dark s u r v i v a l was i n v e r s e l y r e l a t e d to temperature. They suggested t h a t the dark s u r v i v a l p o t e n t i a l of p l a n k t o n i c diatoms, when d i s p l a c e d from the euphotic zone by mixing or s i n k i n g , w i l l vary with s p e c i e s , may be dependent on temperature, and may be prolonged by p e r i o d i c i l l u m i n a t i o n . The mechanisms by which diatoms r e g u l a t e t h e i r depth, i f at a l l , are not f u l l y understood, but the p h y s i o l o g i c a l c o n d i t i o n of the c e l l s i s o b v i o u s l y important. Senescent c e l l s have a higher s i n k i n g r a t e than r a p i d l y r e producing c e l l s ( E p p l e y , et a l . , 1967; Smayda, 1970). S t e e l e and Yentsch (1960) showed how the s i n k i n g r a t e of a p o p u l a t i o n c o u l d i n f l u e n c e the depth of i t s l a y e r of maximum abundance. They demonstrated t h a t a s i n k i n g r a t e which decreased with depth was necessary to account f o r a maximum l a y e r , and hypothesized 88 that phytoplankton p o p u l a t i o n s w i t h i n the euphotic zone, i n the presence of v e r t i c a l s t r a t i f i c a t i o n , may deplete t h e i r n u t r i e n t supply, and, as a conseguence, become denser. As they s i n k i n t o n u t r i e n t - r i c h water below the euphotic zone they a s s i m i l a t e n u t r i e n t s , r e d u c i n g t h e i r s i n k i n g r a t e or r e g a i n i n g n e u t r a l d e n s i t y . Por most s p e c i e s morphological expressions of p h y s i o l o g i c a l senescence have not been observed. Although l a b o r a t o r y experiments i n d i c a t e d that n u t r i e n t d e f i c i e n c y may have c y t o l o g i c a l m a n i f e s t a t i o n s which can be recognized under the microscope (Holmes, 1966), the i n a b i l i t y to recognize senescent o r n u t r i e n t - d e f i c i e n t c e l l s of n a t u r a l populations s e r i o u s l y impedes the r e c o g n i t i o n 'of'senescent p o p u l a t i o n s . During f a l l , however, Skeletonema costatum was r e s t r i c t e d t o depths below 50 m, dominating the p o p u l a t i o n at 75 m, and thus resembling p o s t u l a t e d d e e p - l i v i n g , senescent phases. The c o n c e n t r a t i o n of senescent p o p u l a t i o n s i n a deep l a y e r may be a phase i n the-annual c y c l e of oceanic"diatoms analogous to the f o r m a t i o n of r e s t i n g spores i n the n e r i t i c p o p u l a t i o n s of c e n t r i c diatoms. In both cases, the c e l l s show p h y s i o l o g i c a l a d a p t a t i o n s to p e r i o d s of unfavorable environmental c o n d i t i o n s . In the shallow n e r i t i c environment where the winter mixed l a y e r extends to the bottom, the c e l l s can sink to the bottom, accompanying the formation of h e a v i l y s i l i c i f i e d c e l l w a l l s . Such r e s t i n g spores are a r e g u l a r component of many p l a n k t o n i c diatoms c o n s i d e r e d i n the present study. 89 Regression Analyses Both the t o t a l s t a n d i n g crop and the d i s t r i b u t i o n of s i n g l e s p e c i e s were examined i n t h i s study. These have been used as the dependent v a r i a b l e s i n the i n v e s t i g a t i o n of the p h y s i c a l , c h e m i c a l , seasonal and l o c a t i o n f a c t o r s upon t h e i r d i s t r i b u t i o n p a t t e r n s . The study was conducted by means of m u l t i p l e r e g r e s s i o n a n a l y s i s . L i m i t a t i o n s ' are p l a c e d upon the i n t e r p r e t a t i o n of the r e s u l t s of these analyses, because many of the key assumptions u n d e r l y i n g the m u l t i p l e r e g r e s s i o n technique are v i o l a t e d t o some extent by the data under c o n s i d e r a t i o n . None of v a r i a b l e s a re known to be d i s t r i b u t e d normally; the frequency d i s t r i b u t i o n s of b i o l o g i c a l data are l i k e l y to be s t r o n g l y skewed(Windsor and C l a r k e , 1940; Barnes, 1952). In order t o c o r r e c t t h i s s i t u a t i o n an attempt was made to normalize the data by t r a n s f o r m i n g (logarithm t o the base 10) the dependent v a r i a b l e and thereby a c h i e v i n g c l o s e r approximations to t h e assumptions. In b i o l o g i c a l data i t i s impossible t o o b t a i n the measurements of independent v a r i a b l e s without e r r o r . In p r a c t i c e i t i s assumed t h a t the e r r o r s i n the data of independent v a r i a b l e s are n e g l i g i b l e (Zar, 1974). Evidence i n d i c a t e s t h a t log-normal d i s t r i b u t i o n can be a p p l i e d to phytoplankton abundances ( P a t r i c k , Hohn and Wallace, 1954; MacArthur, 1960; Edden, 1971; T e t t , 1973). Although some'of these v i o l a t i o n s can be minimized by t r a n s f o r m a t i o n of the v a r i a b l e s , they cannot be e l i m i n a t e d . N e v ertheless, i f the r e s u l t s are regarded as only approximate and i n d i c a t i v e , m u l t i p l e r e g r e s s i o n a n a l y s i s remain a u s e f u l and powerful method f o r s e l e c t i n g f o r f u r t h e r 90 i n v e s t i g a t i o n those v a r i a b l e s most l i k e l y to be important i n determining the d i s t r i b u t i o n p a t t e r n of the dependent v a r i a b l e . T o t a l Standing Crop. The t o t a l s t a n d i n g crop of diatoms expressed as numbers of c e l l s per l i t e r may have l i t t l e r e l a t i o n s h i p to the p r o d u c t i v i t y of the area, s i n c e " i t does not c o n s i d e r v a r i a t i o n s i n the p h o t o s y n t h e t i c a c t i v i t y of the diatoms, or the presence of other types of phytoplankton. Consequently; many r e s e a r c h e r s have questioned the value of c e l l counts. However, w i t h i n the marine environment, the s i z e f r e q u e n c i e s of diatoms appeared to be s i m i l a r throughout the ' t r a n s e c t , • s o t h a t the sum may give a r e l i a b l e estimate of q u a n t i t y . Moreover, f o r other a s p e c t s of community ecology, i t i s p r e f e r a b l e to c o n s i d e r s p e c i e s i n terms of i n d i v i d u a l s , these being the b a s i c u n i t s of a s t r u c t u r e d p o p u l a t i o n ( M a r g a l e f , 1958). The m u l t i p l e r e g r e s s i o n of the t o t a l diatom s t a n d i n g crop a g a i n s t environmental parameters (Table IX) suggests t h a t season and l o c a t i o n f a c t o r s may be more important i n p r e d i c t i n g the d i s t r i b u t i o n of the standing crop than n u t r i e n t f a c t o r s . Regression r e s u l t s a r e , of course, non-causal and o n l y e x p l a i n that• 3436 of the v a r i a t i o n of the standing crop a t a l l S t a t i o n s i n the study area can be p r e d i c t e d from changes of the nine s i g i n i f i c a n t v a r i a b l e s . The f a c t that temperature and s a l i n i t y d i d not show s i g n i f i c a n c e i n the pooled data does not mean t h a t there i s no r e l a t i o n s h i p between the diatom standing crop and 91 these two v a r i a b l e s , but t h a t the r e l a t i o n s h i p i s l e s s s i g n i f i c a n t i n terms of the i n d i c a t e d p r o b a b i l i t y l e v e l . From t h i s o b s e r v a t i o n at l e a s t one c o n c l u s i o n can be drawn, namely t h a t season and l o c a t i o n f a c t o r s should be entered i n any reasonable s t a t i s t i c a l d e s c r i p t i o n of phytoplankton d i s t r i b u t i o n s . T h i s c o n c l u s i o n i s a l s o supported by the r e g r e s s i o n r e s u l t s f o r each S t a t i o n and f o r each month, and w i l l be d i s c u s s e d below. I§3£5§sion A n a l y s i s i n Each Month Seasonal trends i n the r e l a t i v e importance of the independent v a r i a b l e s have been examined by summing, over a l l r e g r e s s i o n s (Table X). Of the 16 independent v a r i a b l e s used i n these a n a l y s e s , i n c l u d i n g n i n e dummy v a r i a b l e s of l o c a t i o n and season f a c t o r s , s t a t i o n s and depths most f r e q u e n t l y had s i g n i f i c a n t r e g r e s s i o n c o e f f i c i e n t s ; i n 11 of the 15 analyses(no s i g n i f i c a n t v a r i a b l e found i n February 1973) the r e g r e s s i o n c o e f f i e n t s of one or both of these v a r i a b l e s was s i g n i f i c a n t at the 5% l e v e l . , L o c a t i o n f a c t o r s were c o n s i s t e n t l y predominant i n terms of the amount of v a r i a b i l i t y of the dependent v a r i a b l e which they account f o r . In r e g r e s s i o n s f o r both November and January, the p h y s i c a l parameters accounted l a r g e l y f o r the v a r i a b i l i t y of dependent v a r i a b l e s . Temperature a l s o appeared to be important i n the summer months. In the r e g r e s s i o n s f o r the s p r i u g and summer months i n which the diatoms u s u a l l y reached the maxima i n 92 abundance both l o c a t i o n f a c t o r s and n u t r i e n t f a c t o r s accounted f o r the v a r i a b i l i t y of the diatom s t a n d i n g crop. Thus, although the t o t a l s t a n d i n g crop of diatoms appear to be p r i m a r i l y determined by n u t r i e n t c o n c e n t r a t i o n s , t h e i r d i s t r i b u t i o n was dominated by the l o c a t i o n f a c t o r s such as s t a t i o n s and depths. For n u t r i e n t c o n c e n t r a t i o n s , the winter n u t r i e n t l e v e l was a predominant v a r i a b l e , i n terms of both the"magnitude of the r e g r e s s i o n c o e f f i c i e n t , and the amount of v a r i a b i l i t y accounted f o r . The c o n c e n t r a t i o n of n u t r i e n t s w i t h i n the w i n t e r mixed l a y e r r e p r e s e n t s an ample n u t r i e n t supply. TJiis i s a v a i l a b l e to the phytoplankton at the onset of the s p r i n g bloom. A f t e r s t r a t i f i c a t i o n o f the water column, the a v a i l a b l e n u t r i e n t supply i s augmented p r i m a r i l y by r e g e n e r a t i o n of n u t r i e n t s w i t h i n the mixed l a y e r , and by entrainment a s s o c i a t e d with i n f l o w from the F r a s e r R i v e r . Legare(1957) pointed out t h a t the d e p l e t i o n of s i l i c a t e d uring summer l i m i t s phytoplankton(diatom) growth. However, i n the present study t h i s appeared not t o be the case, because the s i l i c a t e c o n c e n t r a t i o n s known to l i m i t growth are 0.3 -1•5-ug-at S i / 1 (Paasche, 1973) and the s i l i c a t e l e v e l s i n the study area never dropped to the l i m i t i n g l e v e l ( T a b l e V I I . ) . Regression Analyses at Each S t a t i o n Since i t seemed probable t h a t the independent v a r i a b l e s might d i f f e r i n importance i n d i f f e r e n t environmental r e g i o n s , the r e g r e s s i o n procedure was repeated, t r e a t i n g the samples from 93 each of the hydrographic r e g i o n s s e p a r a t e l y . S i l i c a t e c o n c e n t r a t i o n was most s i g n i f i c a n t ( n e g a t i v e l y ) i n s o f a r as v a r i a t i o n s of the diatom standing crop at S t a t i o n 1 was concerned. Depth was d i r e c t l y c o r r e l a t e d with the diatom c o n c e n t r a t i o n , showing p o s i t i v e a r e l a t i o n s h i p with 1 m and negative a r e l a t i o n s h i p with 75 m, r e s p e c t i v e l y . T h i s i n d i c a t e s t h a t there was no apparent l i m i t i n g n u t r i e n t among those measured at S t a t i o n 1. S a l i n i t y , as expected, was most s i g n i f i c a n t l y r e l a t e d to the v a r i a t i o n of diatoms at S t a t i o n 2. Both h o r i z o n t a l and v e r t i c a l d i s t r i b u t i o n of s a l i n i t y was d i r e c t l y r e l a t e d to the freshwater i n p u t of the e s t u a r i n e area. I t i s i n t e r e s t i n g to note that S t a t i o n 2 was the only area'where season o r l o c a t i o n f a c t o r s d i d not appear t o be s i g n i f i c a n t v a r i a b l e s . T h i s i n d i c a t e s t h a t the e n t i r e environmental c o n d i t i o n at S t a t i o n 2 i s r e g u l a t e d by the l a r g e amount of freshwater i n f l o w from the F r a s e r R i v e r . Takahashi, F u j i and Parsons(1973) suggested t h a t l i g h t and n i t r a t e ( o n l y i n summer months) were l i m i t i n g i n the area. Together with r a d i a t i o n data ( f i g u r e s 12 and 1 3 ) i t i s concluded here t h a t l i g h t and s a l i n i t y were the major f a c t o r s i n r e g u l a t i n g the v a r i a t i o n of the diatom s t a n d i n g crop a t S t a t i o n 2. Ammonia c o n c e n t r a t i o n was a s i g n i f i c a n t v a r i a b l e i n the r e g r e s s i o n a n a l y s i s of S t a t i o n s 2 and 3, hwile n i t r a t e and n i t r i t e were s i g n i f i c a n t i n the r e g r e s s i o n a n a l y s i s of S t a t i o n 4. Temperature was a h i g h l y s i g n i f i c a n t v a r i a b l e i n the r e g r e s s i o n a n a l y s i s of S t a t i o n s 4 and 5. Thus, the demonstration of the importance of v a r i a t i o n s i n temperature t o the diatom s t a n d i n g crop i s r e a f f i r m e d , i n the 94 sense t h a t the hydrography of these areas are u s u a l l y r e g u l a t e d by the c o l d , h i g h - s a l i n e water upwelled o f f the coast which i s important i n producing s u r f a c e c u r r e n t p a t t e r n s and m a i n t a i n i n g the diatom p o p u l a t i o n s a t S t a t i o n s 4 and 5. The c o e f f i c i e n t of de t e r m i n a t i o n f o r the r e g r e s s i o n a t S t a t i o n 4 was 0.68 which i s almost twice t h a t a t other S t a t i o n s . F i v e v a r i a b l e s i n c l u d i n g one season f a c t o r and 4 phy s i c o -chemical environmental parameters had a s i g n i f i c a n t r e g r e s s i o n c o e f f i c i e n t f o r t h i s S t a t i o n . The hydrography i n t h i s area i s u s u a l l y r e l a t i v e l y homogeneous with depth due to a c t i v e t i d a l mixing. From- t h i s o b s e r v a t i o n one can conclude t h a t w i t h i n the homogeneous water column more environmental f a c t o r s i n t e r a c t with diatoms than i n s t r a t i f i e d water, and these v a r i a b l e s are h i g h l y s i g n i f i c a n t i n p r e d i c t i n g the v a r i a t i o n s of the diatom s t a n d i n g c r o p s . I t i s apparent t h a t the e c o l o g i c a l parameters which determine the st a n d i n g crop of diatoms may vary from one r e g i o n t o another, and t h a t the r e l a t i o n s h i p between any f a c t o r and sta n d i n g crop may a l t e r under d i f f e r e n t environmental c o n d i t i o n s . On a very broad s c a l e the diatom crop i s p o s i t i v e l y c o r r e l a t e d with a v a i l a b l e n u t r i e n t c o n c e n t r a t i o n s . Within the study area , n i t r a t e c o n c e n t r a t i o n i s i n f l u e n t i a l i n summer when the diatom p o p u l a t i o n s are f l o u r i s h i n g . Other n u t r i e n t s appeared to be present i n adequate amounts duri n g sampling p e r i o d s and may never be exhausted by the phytoplankton. In the study area the supply of n u t r i e n t s i n 95 the e u p h o t i c zone may always be adequate. Thus, the standing crop depends l a r g e l y upon the t o t a l a v a i l a b l e n u t r i e n t s and upon the l o c a t i o n and/or season f a c t o r s . The p h y s i c o - c h e m i c a l parameters, e s p e c i a l l y temperature, are of some importance i n determining v a r i a t i o n s i n summer and winter s t a n d i n g c r o p s , while s a l i n i t y g e n e r a l l y has l i t t l e e f f e c t (except that r e v e a l e d at S t a t i o n 2) . The R e l a t i o n s h i p between I n d i v i d u a l Diatom Pogulations and Environmental Parameters A l l diatoms t h a t have been run with m u l t i p l e r e g r e s s i o n a n a l y s i s were chosen f o r t h i s , because they were dominant s p e c i e s and/or c o n s t i t u t e d one of the major populations i n the diatom community and were' u s u a l l y frequent. As would be expected, a s a l i e n t f e a t u r e of t h i s a n a l y s i s was th a t t h i r t y - t w o of the t h i r t y - f o u r s p e c i e s showed r e l a t i o n s h i p s between themselves and the season and/or l o c a t i o n f a c t o r s (sea p. 62 ). Th i s i n d i c a t e s t h a t sampling l o c a t i o n s and months are very important i n the v a r i a t i o n of diatom p o p u l a t i o n s . R egression analyses of 13 s p e c i e s suggest that these s p e c i e s have some pref e r e n c e f o r subsurface water where they' reach maximum c o n c e n t r a t i o n . On the other hand i n the case of P a r a i i a su.lca.ta t h e r e was a s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p between i t and the 75 m l e v e l . T h i s i n d i c a t e s t h a t t y c h o p e l a g i c diatom s p e c i e s may reach t h e i r maximum production l e v e l i n the deeper l a y e r . Fourteen s p e c i e s e x h i b i t e d a s i g n i f i c a n t r e l a t i o n s h i p between themselves and one or more s t a t i o n s . T h i s i n d i c a t e s t h a t 96 these 14 s p e c i e s may be c o r r e l a t e d with p a r t i c u l a r hydrographic c h a r a c t e r i s t i c s of each s t a t i o n . In seems u n l i k e l y , however, that s a l i n i t y d i s t r i b u t i o n {15. 10-33.58% ) i s a primary f a c t o r i n l o c a l diatom d i s t r i b u t i o n s because only Chaetoceros d i f f i c i l i s showed a s l i g h t l y s i g n i f i c a n t r e l a t i o n s h i p with s a l i n i t y i n t h i s a n a l y s i s . T h i s together with the r e s u l t s of the t o t a l s t a nding crop a n a l y s i s i n d i c a t e s t h a t s a l i n i t y h a r d l y a f f e c t e d the change i n the diatom p o p u l a t i o n s at the s t a t i o n s sampled. For n u t r i e n t parameters, s i l i c a t e appeared to be one o f the main v a r i a b l e s a s s o c i a t e d with the d i s t r i b u t i o n of the diatom s p e c i e s . Analyses o f f o u r t e e n important s p e c i e s i n terms of p o p u l a t i o n s i z e r e v e a l e d a s i g n i f i c a n t negative r e l a t i o n s h i p with s i l i c a t e . T h i s i s probably due to the c l o s e r e l a t i o n s h i p between s i l i c a t e c o n c e n t r a t i o n i n the area and the F r a s e r River d i s c h a r g e , because the Fraser R i v e r i s the major source of s i l i c a t e and the i n c r e a s e of f r e s h water i n f l o w i s u s u a l l y c o i n c i d e n t with the onset of d e c r e a s i n g diatom standing crop. Phosphate c o n c e n t r a t i o n appeared to show: a s i g n i f i c a n t r e l a t i o n s h i p with nine s p e c i e s . Evidence suggests t h a t both marine and f r e s h water diatoms are capable of accumulating s u f f i c i e n t phosphate r e s e r v e s , to nourish themselves i n low phosphate c o n c e n t r a t i o n s : A s t e r i o n e l l a formosa^ a f r e s h water diatom, has been shown t o be capable of accumulating phosphate r e s e r v e s t o provide f o r n e a r l y seven doublings (Mackereth, 1953), and a marine diatom Phaeodactylum t r i c o r n u t u m may provide i n a s i m i l a r way f o r f i v e doublings{Kuenzler and Ketchum, 1962). Thus 97 the growth r a t e of diatoms may not respond at once to a change i n the external'phosphate c o n c e n t r a t i o n . Analyses of Ch,aejfcoceros s i r o i l i s , • C ^ l i n d r o t h e c a c l o s t e r i u m £ Legtocyl.indr us d a n i c u s and N i t z s c h i a d e l i c a t u l a showed - a s i g n i f i c a n t negative r e l a t i o n s h i p between them and n i t r a t e , • and i n the case of Chaetoceros d i f f i c i l i s a s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p between i t and n i t r a t e c o n c e n t r a t i o n s . There appear t o 'be s i g n i f i c a n t p o s i t i v e r e l a t i o n s h i p s between' N i t z s c h i a lcngissima i £ i S h i z o s o l e n i a d£licajtula x S k i 2 2 S o l e n i a s e t i a e r a x and ammonia c o n c e n t r a t i o n s , and "a negative r e l a t i o n s h i p between ammonia and C o s c i n o d i s c u s l i n e a t u s -and T h a l a s s i o s i r a e c c e n t r i c u s . U t i l i z a t i o n of n i t r a t e by phytoplankton i n v o l v e s a c o n v e r s i o n to ammonia with the c e l l before i t can be a s s i m i l a t e d , so i t seems l i k e l y t h a t p h y t o p l a n k t e r s take up ammonia i n preference to n i t r a t e . Evidence suggests t h a t f o r most alg a e , ammonia-N i s used p r e f e r e n t i a l l y ( S y r e t t , 1962; Paasche, 1971). Together with the r e s u l t s of m u l t i p l e r e g r e s s i o n a n a l y s i s of the t o t a l diatom standing crop t h i s supports the hypothesis t h a t the macronutrients i n the study area never l i m i t the growth of phytoplankton. S c h i n d l e r and Holmgren(1971), i n t h e i r r e g r e s s i o n a n a l y s i s i n v o l v i n g phytoplankton production and p r o d u c t i v i t y with 6 environmental parameters i n 19 Canadian S h i e l d Lakes, r e p o r t e d that l i g h t , c h l o r o p h y l l and CC2 were s i g n i f i c a n t v a r i a b l e s g i v i n g an R 2 of 0.61. In g e n e r a l , the m u l t i p l e r e g r e s s i o n 98 a n a l y s i s of the major • p l a n k t o n i c diatom populations r e v e a l e d s i g n i f i c a n t r e l a t i o n s h i p s e x i s t i n g between p l a n k t o n i c diatoms and the environmental parameters, and are i n agreement with the r e s u l t s reported' i n the l i t e r a t u r e . The i n t r o d u c t i o n of dummy v a r i a b l e s f o r season, l o c a t i o n and depth was important i n demonstrating s i g n i f i c a n t d i f f e r e n c e s i n diatom response to environmental f a c t o r s . Species D i s t r i b u t i o n The g u a n t i t a t i v e d i s t r i b u t i o n of 219 species examined i n t h i s study are presented i n Table V I I I . A s a l i e n t f e a t u r e of these d i s t r i b u t i o n s i s the freguency with which i s o l a t e d i n d i v i d u a l s were found separate from the major p o p u l a t i o n s . The f e a t u r e i s p a r t i c u l a r l y evident i n the case of species c o l l e c t e d by net, which were sampled from f a r l a r g e r volumes than the water samples. Of the 219 s p e c i e s , 59 were observed at l e a s t once on the prepared s l i d e s frcm the 5 s t a t i o n s . Because most diatom s p e c i e s can, at times, e x i s t i n environments somewhat d i f f e r e n t from .their u s u a l h a b i t a t s the procedure used t o d e l i m i t a s p e c i e s ' major h a b i t a t must be somewhat a r b i t r a r y . N e v e rtheless, the diatom s p e c i e s can be c l a s s i f i e d a c c o r d i n g to the hydrographic r e g i o n s which' they occupied. The d i s t r i b u t i o n of a few s p e c i e s such as Chaetoceros ceratgspprum f c C o s c i n o d i s u s c u r v a t u l u s x and M e l o s i r a l i n e a t a changed markedly, because at times many s p e c i e s d i s a p p e a r e d and reappeared. 99 Cosmopolitan Species A t o t a l of 28 s p e c i e s i n c l u d i n g 4 l i t t o r a l s p e c i e s , 2 brackish-water s p e c i e s and 1 fresh-water s p e c i e s can be c o n s i d e r e d cosmopolitan as d e f i n e d i n the l i t e r a t u r e (Cupp; 1943; "Smayda; - 1958; Hendey, 1964; Simonsen, 1974) . .-AstS-Eiaifilla g l a c i a l i s , . Chaetoceros ccmpressus n Chaetoceros r a d i c a n s ; £2§cinodiscus lingatSlaLt. N i t z s c h i a longissimax Thai as s i one ma n i t z s c h i o i d e s and T h a l a s s i o s i r a e c c e n t r i c u s were " f a i r l y abundant and frequent i n water samples. S e h r o e d e r e l l a d e l i c a t i j i a was the dominant s p e c i e s a t S t a t i o n s 1 and 5 i n J u l y 1972 and c o n s t i t u t e d one-of the major p o p u l a t i o n s a t S t a t i o n s 2, 3, and 4 at the same time.•A fresh-water s p e c i e s , Synedra •• -u-l-n,a , was o b v i o u s l y t r a n s p o r t e d from the F r a s e r F i v e r and perhaps was a l l o c h t h o n o u s , i n the area of S t a t i o n 2. N e r i t i c Species Since the area of t h i s study was purposely r e s t r i c t e d t o the c o a s t a l environment, n e r i t i c s p e c i e s are the most important component of the diatom communities i n the area. Of the 219 s p e c i e s observed i n the study area 64 s p e c i e s c o u l d be c o n s i d e r e d n e r i t i c s p e c i e s . In the spring/summer blooms these n e r i t i c s p e c i e s , together with the cosmopolitan s p e c i e s Thalassionema n i t z s c h i o i d e s ^ and S c h r o e d e r e l l a d e l i c a t u l a , dominated the diatom community. During t h e - w i n t e r , however, the n e r i t i c s p e c i e s made up h a l f , or l e s s , of the t o t a l ' p o p u l a t i o n , while oceanic s p e c i e s , such as Chaetoceros c o n c a v i g o r n i s and a 100 cosmopolitan t y c h o p e l a g i c s p e c i e s P a r a l i a s u l c a t a , were predominant. S e v e r a l suggestions have been made to e x p l a i n the b i o l o g i c a l d i f f e r e n c e s between the near shore and open ocean environments. Eppley(1970) suggested t h a t d i f f e r e n c e s i n the a b i l i t y of s p e c i e s to u t i l i z e ammonium i o n s as a source of n i t r o g e n may p a r t i a l l y maintain the d i s t i n c t i o n between n e r i t i c and o c e a n i c s p e c i e s . Oceanic s p e c i e s appear to be capable of a s s i m i l a t i n g ammonium io n a t r e l a t i v e l y low c o n c e n t r a t i o n s (0.1-0.6uM)i e n a b l i n g them t o p e r s i s t during the p e r i o d s - of n i t r a t e d e f i c i e n c y which occur f r e q u e n t l y i n the marine environment, N e r i t i c s p e c i e s , on the other hand, i n the presence of adequate c o n c e n t r a t i o n s of n i t r a t e , have a more r a p i d qrowth r a t e than the oceanic s p e c i e s . Some diatom s p e c i e s have been shown to r e q u i r e one or more v i t a m i n s ; B12, thiamine.,Other o r g a n i c substances appear to have a s t i m u l a t o r y e f f e c t on the growth of some s p e c i e s (Droop, 1962; Conrad and Saltman, 1962; P r o v a s o l i , 1971) . The c o n c e n t r a t i o n s of some i n o r g a n i c m i c r o n u t r i e n t s i s a l s o c r i t i c a l , and the presence of organic c h e l a t i n g agents such as EDTA may determine the a v a i l a b i l i t y of such m i c r o n u t r i e n t s to phytoplankton (Lewin and G u i l l a r d , 1963; Fogg, 1975). In the study area Skeletonema costatum was the most abundant s p e c i e s , being dominant i n both s p r i n g and summer T h a l a s s i o s i r a fiacifica occurred o n l y i n e a r l y s p r i n g and c o n s t i t u t e d one'of the major components- of * the- s p r i n g bloom. Chaetoceros a f f i n i s x Clu d e b i l i s x Cju brevis*. C^t- did^mus^ 101 C h ' s i m i l i s f t Ch; s o c i a l i s f D i t j l i u m'•• • b r i g h t we j. 1 i i fc Eucampia 2°iiaSSSx' "Ni t z s c h i a - • s e r i a t a x R h i z o s o l e n i a d e l i c a t u l a , and T h a l a s s i o s i r a a e s t i v a l i s were very abundant and each of them c o n s t i t u t e d an o c c a s i o n a l major p o p u l a t i o n s i n the l o c a l diatom communities. Oceanic Species The s t r a i t of Georgia/Juan de Fuca S t r a i t system contained 23 o c e a n i c s p e c i e s d e f i n e d i n the l i t e r a t u r e {as p r e v i o u s l y quoted). E i g h t s p e c i e s were observed only w i t h i n Juan de Fuca S t r a i t area. U n l i k e the n e r i t i c s p e c i e s , oceanic s p e c i e s were found i n a f l o r a which i s made up of few components. As p r e v i o u s l y pointed out, evidence i n d i c a t e s that the waters of the S t r a i t of Georgia/Juan de Fuca S t r a i t system possesses d i s t i n c t r e g i o n s : southern , i n t e r m e d i a t e and n o r t h e r n waters, and S u b - a r c t i c P a c i f i c Ocean waters(Pickard, 1963; Dodimead, 1963; Herlinveaux and Giovando, 1969). P h y t o p l a n k t e r s are ap p a r e n t l y t r a n s p o r t e d by the c u r r e n t s (Boney, 1975). P l a n k t o n i e l l a s o l , f o r i n s t a n c e , i n d i c a t o r s p e c i e s of t r o p i c a l warm water, occurred at s t a t i o n 5 i n February. T h i s may i n d i c a t e t h a t southern waters extending i n t o the area c a r r y some warm water s p e c i e s . Chaetoceros- c o n c a y i c p r n i s c o l d water s p e c i e s , together with Chaetoceros d e b i l i s , n e r i t i c c o l d water s p e c i e s , were components of the major p o p u l a t i o n s during the f a l l bloom i n the study area. Marine Species 102 ft number of diatom s p e c i e s enjoy a wide d i s t r i b u t i o n and i t i s d i f f i c u l t t o d e c i d e whether t h e i r h a b i t a t s are o c e a n i c or n e r i t i c . A l s o , some other s p e c i e s cannot be c l e a r l y a s s i g n e d to one or the o t h e r , because they are e i t h e r r a r e or newly found s p e c i e s . A l l these s p e c i e s are designated as marine s p e c i e s i n Table V I I I . Eighteen s p e c i e s of t h i s category were r e p r e s e n t e d i n the study -area and m o s t o f them were n e i t h e r abundant nor frequent. N i t z s c h i a d e l i c a t u l a was one of the most abundant s p e c i e s and c o n s t i t u t e d one of the major populations i n s p r i n g and summer. L i t t o r a l .Species Although t h i s study has been p r i m a r i l y r e s t r i c t e d t o the marine p l a n k t o n i c diatoms, a c o n s i d e r a b l e number of s p e c i e s u s u a l l y c o n s i d e r e d to be l i t t o r a l ( 2 2 % of t o t a l number of species) were found i n the plankton samples. Some members of the group may be r e l a t i v e l y important i n p l a n k t o n i c diatom communities, i f they occur there r e g u l a r l y ( t y c h o p e l a g i c species) . Of f o r t y - s i x s p e c i e s found i n the area four s p e c i e s have a l r e a d y been w e l l - d e f i n e d as t y c h o p e l a g i c s p e c i e s . j ? a r a l i a s u l c a t a ^ a cosmopolitan t y c h o p e l a g i c s p e c i e s , i s one of most important. T h i s s p e c i e s was r e g u l a r l y represented throughout the year a t a l l s t a t i o n s . I t c o n s t i t u t e d one o f the major components i n the diatom communities r e g a r d l e s s of seasonal v a r i a t i o n s and 103 was o f t e n dominant i n deeper layers.•••Simonsen( 1974) r e c e n t l y suggested that a l i t t o r a l s p e c i e s Rap_honeis amphiceros should be c o n s i d e r e d as a t y c h o p e l o g i c s p e c i e s on the b a s i s of i t s abundance and frequency i n plankton. In the present m a t e r i a l Cgcconeig c q s t a t a , Cocconeis scutellum and•GrammatQRhora marina were moderately abundant and occurred f r e q u e n t l y as w e l l . Thus, these t h r e e s p e c i e s should a l s o be considered as t y c h o p e l a g i c s p e c i e s , Fresh Water Species I t was t o be expected that seme f r e s h water diatom s p e c i e s would be r e p r e s e n t e d i n the study area, s i n c e s t a t i o n s 1, 2, and 3, are markedly a f f e c t e d by the annual heavy discharge of f r e s h -water from the F r a s e r River, A t o t a l o f 29 s p e c i e s including** b r a c k i s h / f r e s h - w a t e r s p e c i e s were found i n the area and occurred mostly a t S t a t i o n 2. M e l o s i r a i t a l i c s and Synedra ulna were p a r t i c u l a r l y important among the fresh-water s p e c i e s i n terms of abundance and frequency. B r a c k i s h Water Sp e c i e s Nineteen s p e c i e s , i n c l u d i n g 11 marine/brackish s p e c i e s were found throughout the study a r e a . Since the annual d i s t r i b u t i o n of s a l i n i t y i n the area f l u c t u a t e s s u b s t a n t i a l l y t r u e , b r a c k i s h -water s p e c i e s would' f i n d i t d i f f i c u l t t o l i v e i n t h i s environment. O n l y Cy_lindrotheca c l o s t e r i u m , a cosmopolitan e u r y h a l i n e s p e c i e s , was f a i r l y abundant, while the other 17 104 s p e c i e s ( T a b l a VIII) showed very low abundance and frequency during t h i s study. The B i s t r i b u t i o n of Recurrent Species Groups Group I Group 1, the l a r g e s t r e c u r r e n t s p e c i e s group, c o n s i s t s of ten n e r i t i c s p e c i e s and two a s s o c i a t e d s p e c i e s . T h i s group i s c h a r a c t e r i z e d by i t s r e l a t i v e l y l a r g e p o p u l a t i o n s of component species(13,200-1,990,000/1) and the h i g h l y frequent o c c u r r e n c e s . They c o n s t i t u t e d one of the major components o f the diatom community i n the study-area and u s u a l l y occurred throughout the year. Skeletonema costatum-was the most important s p e c i e s i n terms- of both abundance- and frequency. Thaiassionema n i t z s c h i o i d e s was f a i r l y abundant and one of the most f r e q u e n t s p e c i e s . N i t z s c h i a d e l i c a t u l a , , one of s e v e r a l s p e c i e s i n the N i t z s c h i a d a l i c a t i s s i m a complex(Hasle, 1965a), has not been w e l l - d e f i n e d i n terms of d i s t r i b u t i o n . However, the presen t data together with p r e v i o u s o b s e r v a t i o n s i n d i c a t e s t h a t t h i s s p e c i e s has a northern n e r i t i c tendency, being observed only i n C h i l e a n waters i n the southern hemisphere(Hasle, 1965a). P a r a l i a s u l c a t a , one of two a s s o c i a t e d s p e c i e s i n t h i s group, i s a cosmopolitan t y c h o p e l a g i c speciesand very common and abundant. I t always occurred with the other s p e c i e s at a l l s t a t i o n s and depths throughout the year. Another a s s o c i a t e d species Schr.oedere 11 a ^ g i i ^ a t u l a A a cosmopolitan temperate/warm water s p e c i e s , was a l s o very common, and was a dominant s p e c i e s a t s t a t i o n s 1 and 5 105 i n J u l y . Group I I T h i s group i s comprised of s i x n e r i t i c s p e c i e s and one a s s o c i a t e d s p e c i e s . A s a l i e n t f e a t u r e of t h i s group i s t h a t a l l s p e c i e s i n t h i s group are c o l d water s p e c i e s . They occu r r e d from s p r i n g through l a t e f a l l at a l l s t a t i o n s and a l l f o u r depths. These s p e c i e s o f t e n c o n s t i t u t e d one of major components of diatom communities. Chaetoceros conca v i c g r n i s • was u s u a l l y a s s o c i a t e d with other s p e c i e s i n s p r i n g and f a l l months. There was no r e c o r d of i t s presence i n summer. Group I I I Group I I I c o n s i s t s of f i v e temperate n e r i t i c s p e c i e s and two a s s o c i a t e d s p e c i e s . T h i s group i s c h a r a c t e r i z e d by the component s p e c i e s ' which occurred only i n s p r i n g and summer, l i i ^ i s s s i o s i r a p a c i f i c a x one of the l a r g e s t p o p u l a t i o n s p e c i e s , occurred o n l y i n s p r i n g ( A p r i l ) and was predominant a t a l l s t a t i o n s . C y l i n d r o t h e c a c l o s t e r i u m , an a s s o c i a t e d s p e c i e s , i s a cosmopolitan marine/brackish water s p e c i e s . i t occurred throughout the year and was a s s o c i a t e d with other s p e c i e s o f the group i n s p r i n g and summer. Another a s s o c i a t e d s p e c i e s T h a l a s s i o s i r a • sp. B i s a new taxon found i n t h i s study and was moderately abundant i n s p r i n g and summer. Group IV 106 T h i s group c o n s i s t s of four cosmopolitan o c a a n i c / n e r i t i c s p e c i e s . T h i s group was u s u a l l y dominated by Corethron criojgh i l um and T h a l a s s i o s i r a e c c e n t r i c a which o f t e n o c c u r s i n c o a s t a l waters. A l l s p e c i e s of the group are s o l i t a r y s p e c i e s and occurred - f r e q u e n t l y , but not very abundantly except Corethron c r i o p h i l u m , which was one of major components at s t a t i o n s 1,2 and 3- i n October and November; An a s s o c i a t e d s p e c i e s C o s c i n o d i s c u s c e n t r a l i s var. p a c i f i c a was a l s o widely d i s t r i b u t e d s p e c i e s . Group V Group V c o n s i s t s of s i x n e r i t i c s p e c i e s and two a s s o c i a t e d s p e c i e s . These s p e c i e s were moderately f r e q u e n t , but not very abundant. They occurred from s p r i n g through f a l l . These b r i e f comparisions do not c o n t r a d i c t the i d e a t h a t the f l o r a found d u r i n g May 1972-July 1973 i s c h a r a c t e r i s t i c of the S t r a i t of Georgia/Juan de Fuca S t r a i t system. I t appears t h a t the same, or s i m i l a r , groups of s p e c i e s may develop each s p r i n g and summer w i t h i n the study area, though the r e l a t i v e abundances of the s p e c i e s may d i f f e r from year to year. 107 CLASSIFICATION The c l a s s i f i c a t i o n of diatoms has undergone dramatic changes s i n c e Hustedt*s c l a s s i c a l s t u d i e s . These changes are due mainly t o the use of the scanning e l e c t r o n microscope by which a great d e a l of new i n f o r m a t i o n has been added t o our knowledge of the valve s t r u c t u r e of diatoms. Important s t u d i e s have been made by Hasle(1964, 1965a, 1965b, 1972, 1973 a,b,c, 1975), Ross and Sims (1970, 1971, 1972, 1973), F r y x e l l and Hasle(1973) and many others who have r e c e n t l y c o n t r i b u t e d ' to t h r e e s u c c e s s i v e Symposia on Recent and F o s s i l Marine Diatoms held i n 1972, 1974 and 1976. These s t u d i e s have a l t e r e d other c r i t e r i a f o r c l a s s i f i c a t i o n ( e s p e c i a l l y at the s p e c i f i c and/or g e n e r i c l e v e l ) . New i n f o r m a t i o n obtained from the scanning e l e c t r o n microscope should be i n t e r p r e t e d as supplementary to e a r l i e r s t r u c t u r a l concepts based on the l i g h t microscope. The f i r s t widely accepted c l a s s i f i c a t i o n system o f diatoms was i n t r o d u c e d by Schuett i n 1896. He c l a s s i f i e d the diatoms i n t o two main Orders, the C e n t r i c a e and the Pennatae, and s e v e r a l s u b d i v i s i o n s . P o i n t i n g out the weakness of Schuett*s system namely that i t p l a c e s i n the f i r s t group many plankton genera-not possessing a - c e n t r i c or r a d i a l s t r u c t u r e such as B i d d u l p h i a , Chaetoceros^ and R h i z o s o l e n i a Hendey(19 37, 1964) regarded diatoms as comprising a s i n g l e order B a c i l l a r i a l e s . E l i m i n a t i n g the Centricae/Pennate s p l i t , he d i v i d e d the order i n t o ten suborders. Karsten(1928) accepted the d i v i s i o n of the B a c i l l a r i o p h y t a i n t o C e n t r a l e s and Pennales. Hustedt (1930) 108 f o l l o w e d Karsten's g e n e r a l system and made some a l t e r a t i o n s t o i t . Supporting Schuett's b a s i c system, Simonsen (1972) added some id e a s f o r a more n a t u r a l system of the c e n t r i c diatoms. He c o n s i d e r e d the absence/presence of r e s t i n g spores as a c r i t e r i o n of p r i m i t i v e n e s s . although Schuett's system i s the most widely accepted so f a r , some m o d i f i c a t i o n s have i n e v i t a b l y been made i n lower c a t e g o r i e s . Hasle(1973) proposed the f a m i l y T h a l a s s i o s i r a c e a e based on the presence of a marginal r i n g of s t r u t t e d processes and one or more l a b i a t e process i n s i d e the ring.- T h i s new f a m i l y i n c l u d e s - the genera L a u d e r i a , loSSsira^ 5fceletonema A Stephanodiscus^ •• - P l a n k t p n i e l l a € • - D e t o n u l a x i l i n i d i s c u s , B a c t e r i o s i r a x C y c l o t e l l a , and T h a l a s s i o s i r a . However, l a b i a t e processes have -been found i n u n r e l a t e d genera and f a m i l i e s , such as a u l a c o d i s c u s s p e c i e s , A c t i n o c y c l u s species(Ross and Sims, 1972) and a l s o 10 genera of the Araphideae and 5 genera of the Raph i d i o i d e a (Hasle, 1973). Simonsen (1972) suggested t h a t the f a m i l y Hemidiscaceae had to be abandoned as -Hemidiscus WALL, i s only a s e m i c i r c u l a r member of the A c t i n o c j c l u s group. However i n a more recent study(Simonsen, 1975), he has proposed t h a t the family'Hemidiscaceae-should be r e t a i n e d , comprising t h e genera Hemidiscus x A c t i n o c y c l u s and Roperia on the b a s i s of the presence of a pseudonodulus as the main c h a r a c t e r ; Hasle(1975) found - l a b i a t e processes i n the genera S t r e p t o t h e c a x e i t i l u m and lithodesja ium, and-discussed the p o s s i b l e - r e l a t i o n s h i p between these t h r e e genera and R h i z o s o l e n i a ; G u i n a r d i a and D a c t i l i o s o l e n She t r a n s f e r r e d G u i n a r d i a blayyana to Dacty.io§olen and 109 2l£t^liosolen mediterraneus to L t gey. 1 i n dr us, r e s p e c t i v e l y . Another recent i n v e s t i g a t i o n , c o n c e r n i n g the'genus Chaetoceros (Evensen- and Hasle, 1975) has not r e s u l t e d i n any major r e v i s i o n . The r a p i d l y i n c r e a s i n g new i n f o r m a t i o n a t the p r e s e n t time suggests the p o s s i b i l i t y t h a t the c l a s s i f i c a t i o n system a t the f a m i l y l e v e l or higher may soon 1 be r e v i s e d . However, the s e p a r a t i o n between the orders C e n t r a l e s and Pennales s t i l l seems to be v a l i d . S t u d i e s regarding s e x u a l r e p r o d u c t i o n of d i a t o m s { e i g . S t o s c h and Drebes, 1964; Drebes, 1966, 1972; von Stosch e t a l . , 1973) i n d i c a t e t h a t members of the C e n t r a l e s are oogamous whereas those of the Pennales are g e n e r a l l y isogamous. The major morphological d i f f e r e n c e between the two Orders i s the presence of raphe • or a x i a l area (the term pseudoraphe has r e c e n t l y been d i s c a r d e d : Anon., 1975) i n the Pennales. I t has been shown t h a t the Pennales may have evolved from the Eupodiscaceae(Hasle, 1973; Ross and Sims, 1973), and Hasle(1973) suggested t h a t the l a b i a t e process may be the predecessor of the diatom raphe; For the above reasons I accept a C e n t r a l e s -Pennales s e p a r a t i o n , bearing i n mind Simonsen' s ( l 972) c a u t i o n : "We have s t i l l a l o n g way t o go before the diatom system can be c a l l e d a n a t u r a l c l a s s i f i c a t i o n . " The f o l l o w i n g scheme of diatom c l a s s i f i c a t i o n i s used f o r the 'genera and s p e c i e s observed i n the present study. The system mainly f o l l o w s t h a t of Simonsen(1974) with some m o d i f i c a t i o n s based on the l a t e s t a v a i l a b l e i n f o r m a t i o n and upon my own o b s e r v a t i o n s . LIST OF GENERA C l a s s B a c i l l a r i o p h y c e a e Order C e n t r a l e s Suborder C o s c i n o d i s c i n e a e Family Melosiraceae K0ET2ING 1844 Stephanopyxis EHRENBERG Hyalodiscus EHRENBERG * P a r a l i a HEIBERG ...... . M e l o s i r a AGARDH ...... S c h r o e d e r e l l a PAVILLARD L e p t o c y l i n d r u s CLEVE . . Corethron CASTRACANE . Family T h a l a s s i o s i r a c e a e LEBOUR 1930, emend. HASLE 1973 T h a l a s s i o s i r a CLEVE .. P l a n k t o n i e l l a SCHUETI C y c l o t e l l a KUETZING . . Skeletonema GREVILLE . Family Coscinodiscaceae-KOETZING 1844 Co s c i n o d i s c u s EHRENBERG Family Hemidiscaceae HENDEY 1937 A c t i n o c y c l u s EHRENBERG Family H e l i o p e l t a c e a e H. L. SMITH 18 72 111 Syn.: A c t i n o d i s c a c e a e SCHUETT 1896 Actinoptychus EHRENBERG ..... 141 Ara c h n o i d i s c u s DEANE ........ 142 Au l a c o d i s c u s EHRENBEfiG 142 Family Astarolampraceae fl. L. SMITH•1872 Asteromphalus EHRENBERG ..... 142 Suborder R h i z o s o l e n i i n e a e Family Rhizosoleniaceae PETIT 1863 R h i z o s o l e n i a EHRENBERG ...... 142 Ditylum BAILEY .............. 144 Gu i n a r d i a H. PERAG ALLQ ...... 144 Lithodesmium EHRENBERG ...... 144 Family Chaetoceraceae H. L. SMITH 1872 Chaetoceros EHRENBERG ....... 145 Bacteri a s t r u m SHADBOLT ...... 151 Suborder B i d d u l p h i i n e a e Family Hemiaulaceae HEIBERG 1863 Hemiaulus EHRENBERG ......... 151 C e r a t a u l i n a H. PERAGALLO .... 152 Eucampia EHRENBERG .......... 152 Family Biddulphiaceae KUETZING 1844 B i d d u l p h i a GRAY ............. 154 Trigonium CLEVE .............. 156 Isthmia AGARDH 157 Order Pennales Suborder Araphidineae 112 Family Diatomaceae DUMORTIER 1822 Rhabdonema KUETZING ......... 158 Grammatophora EHRENBERG ..... 158 Licmophora AGARDH ........... 159 S t r i a t e l l a AGARDH ........... 159 T a b e l l a r i a EHRENBERG ........ 160 Plagiogramma GREVILLE ....... 161 Rhaphoneis EHRENBERG ........ 161 F r a g i l a r i a LYNGBYE .......... 161 Synedra EHRENBERG ........... 162 Thalassionema GRUNOW ........ 164 T h a l a s s i o t h r i x CLEVE & GR0NOW 165 A s t e r i o n e l l a HASSAL ......... 165 Suborder Monoraphidineae Family Achnanthaceae KUETZING 1844 Achnanthes BORY ............. 166 Cocconeis EHRENBERG ......... 167 Rhoicosphenia GRUNOW ........ 169 Suborder B i r a p h i d i n e a e Family Naviculaceae KUETZING 1844 D i p l o n e i s EHRENBERG ......... 169 Mastogloia THWAITES ......... 170 Na v i c u l a BORY 170 C a l o n e i s CLEVE ....... ....... 173 Cymbella AGARDH 173 P i n n u l a r i a EHRENBERG 174 Trac h y n e i s CLEVE ............ 174 113 F r u s t u l i a AGARDH 174 Tr o p i d o n e i s CLEVE ........... 175 Amphora EHRENBERG ........... 175 Pleurosigma W. SMITH ........ 176 Gyrosigma HASSAL ............ 178 Haslea SIMONSEN .............. 180 Family Epithemiaceae GRUNOW 1860 Epithemia De BREBISSON ...... 182 Rhopalodia 0. MOELLER ....... 182 D e n t i c u l a KUETZING 182 Family N i t z s c h i a c e a e GRONOW 1860 Hantzschia GRONOW ........... 183 B a c i l l a r i a GMELIN ........... 183 N i t z s c h i a HASSALL ........... 184 C y l l n d r o t h e c a RABENHORSX .... 188 Family S u r i r e l l a c e a e KUETZING 1844 S u r i r e l l a TURPIN ............ 189 Campylodiscus EHRENBERG ..... 189 114 SUMMARY AND CONCLUSIONS T h i s study was designed t o i n v e s t i g a t e the temporal and s p a t i a l d i s t r i b u t i o n of diatom s p e c i e s i n the S t r a i t of Georgia/Juan de Fuca S t r a i t system, and to review the taxonomy of l o c a l s p e c i e s a p p l y i n g recent taxonomic c r i t e r i a . I t was di s c o v e r e d t h a t t h e r e are two d i s t i n c t p a t t e r n s i n the seasonal d i s t r i b u t i o n of diatom communities i n the study area. These two pat t e r n s are mainly due to physico-chemical p r o p e r t i e s o f the waters i n the area. In the f i r s t p a t t e r n diatom abundance reached a peak i n l a t e s p r i n g (April-May) f o l l o w e d by an a d d i t i o n a l peak duri n g the summer months which was u s u a l l y l e s s abundant than the f i r s t peak. Another peak occurred i n the f a l l and the community at t h i s time was made up of r e l a t i v e l y l a r g e diatom s p e c i e s which c o n s t i t u t e d the major p r o p o r t i o n . In the spring-summer peak the community u s u a l l y c o n s i s t e d of s m a l l e r diatom s p e c i e s . The diatom communities of the southern S t r a i t of Georgia(except f o r the v i c i n i t y of the F r a s e r River plume) are c h a r a c t e r i z e d by t h i s d i s t r i b u t i o n a l p a t t e r n . In c o n t r a s t , the diatom communities i n Juan de Fuca S t r a i t area showed one major p e r i o d of abundance d u r i n g the summer months(June-September). The diatcm community i n the subsurface l a y e r of the F r a s e r River e s t u a r y showed s i m i l a r i t i e s to the second d i s t r i b u t i o n a l p a t t e r n mentioned above, while communities below 25m g e n e r a l l y f o l l o w e d the f i r s t p a t t e r n . The v e r t i c a l d i s t r i b u t i o n of marine diatoms i s random 115 w i t h i n the mixed l a y e r . However, i n the presence of a temperature g r a d i e n t (supposedly a d e n s i t y g r a d i e n t ) , diatom p o p u l a t i o n s may be h i g h l y s t r a t i f i e d . In extreme c a s e s , as i n the areas of the S t r a i t of Georgia ( S t a t i o n s 1 and 2) two d i s t i n c t communities may occupy the same water column at d i f f e r e n t depths. The major diatom population at any s t a t i o n does not n e c e s s a r i l y occur w i t h i n the upper l a y e r . On the other hand, l a r g e p o p u l a t i o n s were not observed below 50 m except i n Haro S t r a i t , a s t r o n g mixing area (Waldichuk, 1957). C e l l s which s i n k below t h i s depth are presumably l o s t from the producing p o p u l a t i o n . The d i s t r i b u t i o n of t o t a l diatom standing c r o p showed stro n g s e a s o n a l f l u c t u a t i o n s i n the study area as was expected. O v e r a l l , s p r i n g and/or summer sta n d i n g crops appeared to be determined by the n u t r i e n t c o n c e n t r a t i o n s a v a i l a b l e at the onset of the s p r i n g peak of p r o d u c t i o n . These are s t r o n g l y c o r r e l a t e d with the p h y s i c a l c o n d i t i o n s ( l i g h t and temperature). R e g r e s s i o n a n a l y s i s of t o t a l diatom s t a n d i n g crop r e v e a l e d t h a t the s t a n d i n g crops are s i g n i f i c a n t l y r e l a t e d with both p h y s i c o -chemical f a c t o r s and s e a s o n / l o c a t i o n f a c t o r s , and that f o r the d e t e r m i n a t i o n of v a r i a t i o n s i n diatom s t a n d i n g crop s e a s o n / l o c a t i o n f a c t o r s appeared to be more important than physico-chemical f a c t o r s . The d i s t r i b u t i o n of 33 diatom s p e c i e s which are v e r y common i n terms of frequency and abundance were i n v e s t i g a t e d . No g e n e r a l d i s t r i b u t i o n a l pattern of i n d i v i d u a l diatom s p e c i e s i n 1 16 the area was found. The d i s t r i b u t i o n of each s p e c i e s v a r i e d l a r g e l y with seasons and depths, showing d i f f e r e n t responses to physico-chemical parameters. The p r i n c i p a l diatoms which were r e s p o n s i b l e f o r the' abundance and/or dominance i n diatom communities a r e i Skeletonema costatum A Chaetoceros d e b i l i s * . P a r a l i a s u l c a t a ^ S e h r o e d e r e l l a d e l i c a t u l a ^ Thai assiosJ.ra B a c i f i c a x Chaetoceros c o n c a v i c o r n i s x Corethron c r i o p _ h i l u m x and E i t z s c h i a d e l i c a t u l a ^ Regression a n a l y s i s of these s p e c i e s with environmental f a c t o r s showed s i m i l a r r e s u l t s as those o f the t o t a l standing crop. A n a l y s i s of r e c u r r e n t s p e c i e s groups i n d i c a t e d t h a t the freguent and abundant s p e c i e s appear to be s i g n i f i c a n t l y a s s o c i a t e d . Groupings of the r e c u r r e n t s p e c i e s were l a r g e l y dependent on hydrographic domains (e.g. n e r i t i c , c o l d water, warm water) and seasons r a t h e r than l o c a t i o n or depth. The f l o r a of the S t r a i t of Georgia/Juan d e F u c a S t r a i t system which was found i n t h i s study c o n s i s t s of a t o t a l of 219 taxa i n c l u d i n g 191 s p e c i e s , 2 s u b s p e c i e s , 23 v a r i e t i e s and 3 forms. The 219 diatom taxa are a t t r i b u t e d t o 66 genera w i t h i n 16 f a m i l i e s and of 219 taxa three appeared t o be new s p e c i e s and f i v e t o be new i n f r a s p e c i f i c t a x a . S i x t y - e i g h t taxa r e p o r t e d are new r e c o r d s f o r western Canada. The u s u a l h a b i t a t s o f the recorded diatom taxa vary due to the hydrographic c h a r a c t e r i s t i c s of the study area. Thus, the f l o r a i n c l u d e s 128 marine p l a n k t o n i c s p e c i e s , 43 marine l i t t o r a l s p e c i e s , 9 brackish-water s p e c i e s , 11 marine/brackish s p e c i e s and 28 fresh-water s p e c i e s ( the d i s t r i b u t i o n of fresh-water s p e c i e s was r e s t r i c t e d t o areas of 117 the F r a s e r River e s t u a r y and Boundary Pass) . From the present study a few problems are raxsed f o r f u t u r e i n v e s t i g a t i o n . There i s a need f o r l a b o r a t o r y work on both p h y s i o l o g i c a l t o l e r a n c e s and morphological v a r i a t i o n s of diatom s p e c i e s . In p a r t i c u l a r , the problem of diatom r e s t i n g spores demands a t t e n t i o n . More i n f o r m a t i o n i s needed on the environmental f a c t o r s which induce r e s t i n g spores and e x s p o r u l a t i o n and on the d u r a t i o n of s u r v i v a l of r e s t i n g spores In the absence o f l i g h t , a d d i t i o n a l f i e l d o b servations are a l s o needed before determining under what c o n d i t i o n s p o p u l a t i o n s produce r e s t i n g spores and s i n k out of the euphotic zone, and we need t o know whether or not t h i s i s a r e g u l a r stage of t h e i r s easonal c y c l e . For b e t t e r f l o r i s t i c s t u d i e s continuous o b s e r v a t i o n s over l o n g e r p e r i o d s are needed in the a r e a , s i n c e the occurrence of diatom s p e c i e s , e s p e c i a l l y the r a r e s p e c i e s , v a r i e s from year to year. 118 SYSTEMATIC ACCOUNT A t o t a l of 219 taxa i n c l u d i n g 190 s p e c i e s , 2 s u b s p e c i e s , 23 v a r i e t i e s and 3 forms of diatoms were recognized d u r i n g t h i s study. Of the 219 taxa, 171 are considered to be marine s p e c i e s , 8 brackish-water s p e c i e s , 11 marine/brackish water s p e c i e s and 29 fresh-water s p e c i e s . Fresh-water s p e c i e s a r e e v i d e n t l y i n t r o d u c e d i n t o the study area from the Fra s e r River and most of them - were observed at s t a t i o n 2, the F r a s e r River plume. Marine s p e c i e s i n c l u d e 43 l i t t o r a l forms which appeared w i t h i n the 75m water column. Three s p e c i e s and f i v e v a r i e t i e s from the present study w i l l be new taxa when p u b l i s h e d . For the purpose of t h i s t h e s i s they 'are given parasystematic s t a t u s . Of the t o t a l taxa s i x t y - e i g h t are new records f o r western Canada, The i n f o r m a t i o n concerning new and previous r e c o r d s of a l l s p e c i e s t r e a t e d are given i n the Appendix. For the i d e n t i f i c a t i o n of these s p e c i e s * e x t e n s i v e use was made of Hustedt's Die Kiaselagen Deutschlandsx Q e s t e r r e i c h s and der Schweiz, I ; I I and I I I (1929-1966), Gran and Angst's Plankton Ma^SSS of Puget Sound (1931), Cupp's study on Tte marine plankton diatoms' of "the West Coast of North America (1943) , C l e v e - E u l e r ' s Die piatomeen von Schweden' and F i n n l a n d x I-V (1951-1955), Hendey's re c e n t p u b l i c a t i o n on the diatoms of B r i t i s h c o a s t a l waters(1964) and Simonsen's l a t e s t study on the marine • p l a n k t o n i c diatoms from the Ind i a n Ocean E x p e d i t i o n (1974)* Brunel(1962) was p a r t i c u l a r l y u s e f u l f o r i d e n t i f y i n g the genus Chaetoceros, and Hasle(1964,1965a,b) f o r 119 the genera N i t z s c h i a and F r a g i l a r i o p s i s . A lso; both P e r a g a l l o ' s study (1891-1908) and A. Schmidt*s AtI§.S der Di^tomaceenkunde (1874-1959) were very u s e f u l . Each taxon i s accompanied by one or more r e f e r e n c e s which are u s u a l l y r e l i a b l e f o r i d e n t i f i c a t i o n . Synonyms are g i v e n o n l y f o r the taxa •whose name have been changed s i n c e Hustedt*s study (1929-1966) . In most cases, no attempt was made to present complete taxonomical d e s c r i p t i o n ; the measurements and o b s e r v a t i o n s are intended merely t o supplement e x i s t i n g d e s c r i p t i o n s . In these cases and i n d e s c r i b i n g some new taxa, the terminology and d i a g n o s t i c system which was recommended i n the " T h i r d Symposium on Recent and F o s s i l Marine Diatoms" (1975) has been adopted. A l l genera and s p e c i e s t r e a t e d i n t h i s study are arranged i n the order of the scheme p r e v i o u s l y g i v e n and the s p e c i e s w i t h i n the genera are a l p h a b e t i c a l . I l l u s t r a t i o n s of a l l taxa t r e a t e d i n t h i s paper are given below. The d i s t r i b u t i o n s of the s p e c i e s were determined on the b a s i s of the q u a n t i t a t i v e i n v e s t i g a t i o n s of the water samples and examinations of s l i d e s prepared from the net c o l l e c t i o n s . Because of the large-volumes of water sampled by the n e t s , many of the r a r e s p e c i e s were observed o n l y on the s l i d e s . 120 C l a s s B a c i l l a r i o p h y c a a e Order C e n t r a l e s Suborder C o s c i n o d i s c i n e a e Family Melosiraceae KOETZING Genus StephanoPixis EHRENBERG Stephanopyxis n i p p o n i c a GRAN & YENDO PlT U,~fiq7~1~ Cupp, 1943, p. 43, f i g . 5 C e l l s c y l i n d r i c a l , oblong to s p h e r i c a l i n g i r d l e view, united to form c h a i n s . Valves c i r c u l a r , covered with s t r o n g and i r r e g u l a r hexagonal a r e o l a t l o n . Hexagonal a r e o l a e 6-8 i n 10/ivm-. Diameter of valve 22-31^tm. Stout long s p i n e s on the va l v e 4-6, a r i s i n g from the centre of each valve and d i r e c t l y r e a c h i n g the valve s u r f a c e of adjacent c e l l . Spines i n other Steahanopy.xis s p e c i e s connect with the ends of the s p i n e s of adjacent c e l l s . T h i s s p e c i e s i s n e r i t i c with a d i s t r i b u t i o n from a r c t i c to temperate r e g i o n s . I t was found f r e q u e n t l y during s p r i n g i n the study area, but was not abundant. -' Genus Hy.alodiscus EHRENBEBG S i a l o d i s c u s s u b t i l i s BAILEY Pl.~~4, f i g . 2 Hustedt 1927-30, p.291, fig.132 T h i s i s a n e r i t i c s p e c i e s common i n the A r c t i c and was observed only on prepared s l i d e s from S t a t i o n s 3,4, and 5 du r i n g Winter and e a r l y s p r i n g . Genus P a r a l i a HEIBERG 121 P a r a l i a s u l c a t a (BHR.) CLEVE Pi.- 4, f i g s . '3a, b Hendey 1964, p. 73, p i . 23, f i g . 5 Syn.: H a l o s i r a s u l c a t a (EHR.) KUETZING Hustedt 1927-30,"p. 276, f i g s . 118-119 Present o b s e r v a t i o n of e x t e r n a l s t r u c t u r e s supplements Heimdal's f i n d i n g s ( 1 9 7 3 , which d i d not demonstrate the i n t e r n a l s t r u c t u r e ) . The a r e o l a t i o n on the i n t e r n a l valve s t r u c t u r e i s the r a d i a l , f a s c i c u l a t e type with a s t r u t t e d process i n the middle and a marginal r i n g of s t r u t t e d processes. A l a b i a t e process i s l o c a t e d i n s i d e the r i n g , and c l o s e to the r i n g . The names P a r a l i a s u l c a t a and M e l o s i r a s u l c a t a are both being used c u r r e n t l y . The valve s u r f a c e i n the genus P a r a l i a possesses e l e v a t e d r a d i a l outgrowths and a marginal r i n g of s t r u t t e d processes i s d i f f e r e n t from the valve s t r u c t u r e of the genus Mel o s i r a , ' which u s u a l l y does not possess those s t r u c t u r e . A l s o , as Simonsen(1974) p o i n t e d out, b e t t e r knowledge of diatom v a l v e s due to SEM confirms that the genus Melosira- as p r e v i o u s l y conceived p r e s e n t l y comprises s e v e r a l n a t u r a l genera, fiaralia being one of them. T h i s s p e c i e s i s a very common t y c h o p e l a g i c diatom with world-wide d i s t r i b u t i o n . In the study area t h i s s p e c i e s occurred year round and at a l l 5 s t a t i o n s . Although the p o p u l a t i o n was never n u m e r i c a l l y h i g h , t h i s s p e c i e s was one of a few dominant s p e c i e s i n winter when diatom abundance was very low. Genus M e l o s i r a EHfiEHBERG M e l o s i r a g r a n u l a t a (GRUN.) 0. MUELLER var. 122 anqustissima 0. MOELLER PI. 4, f i g . ~ 4 Hustedt 1927-30, p. 250, f i g . 104d A freshwater taxon, observed only at s t a t i o n 2 i n l a t e S p r i n g . M e l o s i r a i s l a n d i c a 0. MUELLER subsp. h e l v e t i c a 0. MUELLER PI. T, f i g . 1 Hustedt 1927-30, p. 254, f i g . 107 A freshwater taxon, observed a t s t a t i o n s 2 and 4 d u r i n g f a l l and winter. M g l o s i r a i t a l i c a (EHR.) KUETZING P i . 4 , " f i g . 5 Hustedt 1927-30, p. 257, f i g . 109a A freshwater and marine l i t t o r a l s p e c i e s . This s p e c i e s common during f a l l and winter, but not abundant. M e l o s i r a i t a l i c a (ERH.) KUETZING subsp. s u b a r c t i c a O. MUELLER PI 4, f i g . ~ 6 ~ Hustedt 1927-30, p. 261, f i g . 109b A marine l i t t o r a l s p e c i e s , observed dur i n g w i n t e r and s p r i n g . M e l o s i r a m o n i l i f o r m i s (0. MUELLER ) AGARDH PI 4 f i g . ~ 7 ~ Hustedt 1929-30, p. 236, f i g . 98 Hendey 1964, p. 72, p i . 1, f i g . 2 Syn.: M e l o s i r a l i n e a t a (DILLW.) AGARDH Cl e v e - E u l e r T ~195l, p. 29, f i g . 21 a-c. A common brackish-water s p e c i e s , but r a r e i n t h e study 123 area. Observed a t S t a t i o n s 3 and 4 i n e a r l y s p r i n g . M e l o s i r a nummuloides (DILLW.) AGARDH Pl7 4, f i g7 8 Hustedt 1927-30, p. 231, f i g . 95 A marine l i t t o r a l and e s t u a r i n e s p e c i e s , observed only a t S t a t i o n 1 during e a r l y summer. Me l o s i r a s o l (EHR.) KUETZING P l . 5, f i g s . 1a,b Hustedt 1927-30, p. 270, f i g . 115 F r u s t u l e s i n f i l a m e n t s , disc-shaped, with r a d i a l rows of f i n e punctae. Valves p l a i n , h y a l i n e at the c e n t e r , a r e o l a t i o n running i n coarse c o s t a l r a y s , a r e o l a e about 4 i n 10pm. Diameter of valve about 50um, Th i s s p e c i e s i s marine and known i n southern seas, but P e r a g a l l o found i t on Normandy shores. T h i s was observed o n l y on net-sample s l i d e s from S t a t i o n s 3 and 4 i n March. M e l o s i r a v a r i a n s AGARDH Pl7 4~7~fig. 9 Hustedt 1927-30, p. 240, f i g . 100 A freshwater s p e c i e s , t h i s i s a allochthonous form i n the area and was observed a t S t a t i o n 1, 2 and 3 during s p r i n g . Genus S c h r o e d e r e l l a PAVILLARD S c h r o a d e r e l l a d e l i c a t u l a (PERAG.) PAVILLARD P l . 5, f i g s . 2a,b Hustedt 1927-30, p. 551, f i g . 314 124 Hendey 1964, p. 142, p i . V, f i g . 4, p i . V I I , f i g . 6 Syn.: D e l i c a t u l a pumila (CASTRACANE) SCHOETT Hasle 1973, p. "l8, f i g s . 69-76 S c h r o e d e r e l l a d e l i c a t u l a form. s c h r o e d g r i l (BERGON) SOORNIA Sournia 1968, p. 61, p i . 1, f i g . 4 Hasle (1973) c o n s i d e r e d t h i s s p e c i e s to be c o n s p e c i f i c with Detonula pumJsIS a ^ d consequently she : r e j e c t e d the genus S c h r o e d e r e l l a PAVILLARD, because S. d e l i c a t u l a i s the only s p e c i e s i n the genus ( T a y l o r , 1966, having shown that S . ' s c h r o e d e r i i s a post-auxospore form). However, i t must be p o i n t e d out t h a t there are s t i l l some grounds by which we can maintain t h i s taxon. The genus S c h r o e d e r e l l a i s m o r p h o l o g i c a l l y s i m i l a r to the genera Detonula and Lauderia. In these genera c e l l s are c y l i n d r i c a l and weakly s i l i c i f i e d . G i r d l e s are composed of numerous i n t e r c a l a r y bands. Lauderia can be e a s i l y d i s t i n g u i s h e d from the other two by the presence of i r r e g u l a r l y s c a t t e r e d s t r u t t e d processes over the valve f a c e . In the other two there i s a marginal r i n g of s t r u t t e d processes and a h y a l i n e valve f a c e . In S c h r o e d e r e l l a d e l i c a t u l a the valve of the c e l l i s s l i g h t l y convex with a concave d e p r e s s i o n i n the c e n t e r where adjacent c e l l s are connected by a c e n t r a l spine. The margin i s surrounded by a row of s t r u t t e d processes by which the c e l l s are u s u a l l y i n t e r l o c k e d t o form c h a i n s . On the other hand, i n Detonula s p e c i e s , the v a l v e i s almost f l a t with a very s l i g h t l y depressed c e n t e r . The marginal r i n g c o n s i s t s of s t r u t t e d 125 processes which are s h o r t , s t r o n g - l o o k i n g , t o o t h - l i k e s p i n e s . These processes l i n k the adjacent c e l l s together, forming t i g h t e r connections between c e l l s than i n t h e genus S c h r o e d e r e l l a . C h l o r o p l a s t s , although c o n s i d e r e d to be only a secondary taxonomic c h a r a c t e r , are s m a l l , numerous, r e c t a n g u l a r p l a t e s , u s u a l l y s t o n g l y s l i t , i n S c h r o e d e r e l l a d e l i c a t u l a but c o n s i s t of s e v e r a l p a r i e t a l , rounded p l a t e s in Detonala s p e c i e s . T h i s i s a cosmopolitan s p e c i e s f a v o u r i n g c o a s t a l waters. In the study area t h i s s p e c i e s was one of the major p o p u l a t i o n s during June and J u l y . Genus L e p t o c y l i n d r u s CLEVE L®£tocjlindrus danicus CLEVE P l . 5, f i g . 3 Hustedt 1927-30, p. 558, f i g . 319 A n e r i t i c s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y ccmmon and moderately abundant during s p r i n g . L e p t o c y l i n d r u s jnediterraneus (H. PER AG.) HASLE P l . ~ 5 , fig7 4 ~ Hasle 1975, p. 124, f i g s . 121-130 Syn.: D a c t y l i q s o l e n mediterraneus (H. PERAG.) h. P e r a g a l l o Hustedt 1927-307 P. 556, f i g . 317 Hasle 1S74, f i g . 97 Simonsen 1974, p. 8, f i g . 1 T h i s s p e c i e s was t r a n s f e r r e d from genus D a c t v l i o s o l e n by Hasle(1975) on the b a s i s of s i m i l a r i t y i n c h a r a c t e r s of the v a l v e face to L e p t o c y l i n d r u s danicus. A n e r i t i c s p e c i e s , not very common i n the study a r e a . 126 Genus Corethron CASTRACANE Corethron c r i o D h i l u m CASTRACANE PI. 5, f i g s . A,b Hendey 1937, p. 325, p i . 7.8 Hendey 1964, p. 144, p i . VII, f i g . 4 F r y x e l l and Hasle 1971, p. 335, f i g s . 2-6 Syn.: Corethron h ^ s t r i x HENS EN Hustedt 1927-30, p. 547, f i g . 311 Cupp 1943, p. 70, f i g s . 34 a-c Corethron pelagicum BRUN Hustedt l927 - 3 0 7 pT 547, f i g . 312 T h i s s p e c i e s i s extremely v a r i a b l e (Hustedt, 1958). Hendey (1937) c l e a r e d up the complexity i n both taxonomy and morphology, e s t a b l i s h i n g the f a m i l y Corethronaceae w i t h i n suborder S o l e n i i n e a e , In recent i n v e s t i g a t i o n s ( H e n d e y , 1974; Simonsen, 1974) the genus Corethron has been placed i n the f a m i l y Melosiraceae because the genus possesses n e i t h e r s t r u t t e d nor l a b i a t e p r o c e s s e s . However; F r y x e l l and Hasle(1971), who have presented a more e x t e n s i v e d i s c u s s i o n of the d i s t r i b u t i o n and s t r u c t u r e , p l a c e d , t h i s s p e c i e s i n the R h i z o s o l e a i a c e a e and, more r e c e n t l y , Hasle(1975) suggested t h a t the f a m i l y name Le p t o c y l i n d r a c e a e LEBOUR might be r e t a i n e d with d i f f e r e n t c i r c u m s c r i p t i o n and t h a t the genus Corethron could be i n c l u d e d w i t h i n the f a m i l y . Here, I wish to r e t a i n genus Corethron w i t h i n the f a m i l y a e l o s i r a c e a e f o r the time being u n t i l more evidence i s o b t a i n e d . . T h i s s p e c i e s i s a cosmopolitan s p e c i e s that has i t s l a r g e s t p o p u l a t i o n s i n the A n t a r c t i c i n s h o r e waters (Hasle, 1969). In the study area t h i s s p e c i e s comprised one of the l a r g e s t diatom p o p u l a t i o n s during s p r i n g and f a l l , 127 Family T h a l a s s i o s i r a c e a e LSBOUR emend. Hasle Genus T h a l a s s i o s i r a CLEVE Ifealassiosira a e s t i v a l i s GRAN ' ~ P l 7 6 , ~ f ig7~~T Gran & Angst 1931, p. 436, f i g . 10 T h i s s p e c i e s can be e a s i l y confused with T h a l a s s i o s i r a S2£^SH§ii°§idii i n both g i r d l e and v a l v e view. In Th. a e s t i v a l i s the marginal s t r u t t e d processes are l a r g e r i n number and s h o r t e r than i n Th. n o r d e n s k i g e l d i i . Diameter of valve f a c e 21^ um, ar e o l a e p a r a l l e l t o medium l i n e , about 19 i n 10jum. Th i s s p e c i e s i s known as a n e r i t i c form. In the study area c o n s i d e r a b l e abundance was observed d u r i n g l a t e s p r i n g . !Mi£§siosira a n g s t i i (GRAN) MAKAROVA Pl7 6, figs7 2a;b F r y x e l l 1975, p. 66, f i g s . 25,26 Syn,: C o s c i n o d i s c u s a n g s t i i GRAN Gran & Angst 1931, p.~443, f i g s . 19,20 Valves arched with f l a t c e n t e r when seen i n g i r d l e view. C e l l s u s u a l l y s o l i t a r y . A r e o l a t i o n of the valve r a d i a l , f a s c i c u l a t e d , d i v i d i n g the valve i n t o 12-14 s e c t o r s , a r e o l a e about 20 i n 10jam at the c e n t e r , about 24 a t the margin. E x t e r n a l foramina about 14 i n 10yjm. A row of s t r u t t e d processes run i n t e r n a l t o the e x t e r n a l foramina, the s t r u t t e d processes about 6-7 i n ' 10yum. S e v e r a l long, hollow processes i r r e g u l a r l y arranged (these are t h e most d i s t i n g u i s h a b l e c h a r a c t e r i s t i c s and the term occluded processes has been suggested i n the T h i r d Symposium on Recent and F o s s i l Marine Diatoms, 197 5) . A s i n g l e 128 s t r u t t e d process i n the f l a t c e n t e r . Diameter of valve 48-62yim. T h i s taxon has been c o r r e c t l y t r a n s f e r r e d i n T h a i a s s ^ q s i r a • due to the above c h a r a c t e r s . T h i s s p e c i e s has been seen on l y i n a l i m i t e d area s i n c e i t was found i n Puget Sound by Gran and Angst. D i s t r i b u t i o n of the s p e c i e s i s probably l i m i t e d to the North P a c i f i c c o a s t a l waters. In the study area t h i s s p e c i e s was f a i r l y common i n winter but never i n l a r g e numbers. T h a l a s s i o s i r a d e c i p i e n s (GRUN.) JOERGENSEN PI. 6, f i g s . 3a,b Hustedt 1927-30, p. 322, f i g . 158 C e l l s i n g i r d l e view barrel-shaped t o r e c t a n g u l a r with rounded margins. Diameter of the valve 20-38^im, P e r v a l v a r a x i s u s u a l l y 1/2 diameter of valv e . C h l o r o p l a s t s s m a l l p l a t e s , many, l y i n g c l o s e t o the v a l v e s . Chains long, spaces between c e l l s l a r g e . Valves s l i g h t l y convex. Areolae about 16 i n 10yura, the rows of areol a e arranged i n curved l i n e s forming the e c c e n t r i c a type. Valve margin f u r n i s h e d with a r i n g of strong and s l i g h t l y curved s t r u t t e d processes with a l a b i a t e p r o c e s s . S i n g l e s t r u t t e d process present at valve c e n t e r . A n e r i t i c and n o r t h temperate s p e c i e s . In the study area f a i r l y common but never l a r g e i n numbers. T h a l a s s i o s i r a e c c e n t r i c a (EHR.) CLEVE PI. 7, f i g s . 1a,b F r y x e l l & Hasle 1972, p. 300, f i g s . 1-18 Simonsen 1974, p. 9, p i . 2, f i g s . 1-3 Syn.: C o s c i n o d i s c u s e c c e n t r l c u s EHRENBERG 129 Hustedt 1927-30, p. 388, f i g . 201 T h a l a s s i o s i r a a f f i n i s b a l t i c a Somers "19727 p.. 308, f igs7~TT-15 T h i s s p e c i e s i s one of the most d i f f i c u l t t o i d e n t i f y because of the v a r i e t y of i t s valve s t r u c t u r e and i t s s i m i l a r i t y t o other s p e c i e s . An e x c e l l e n t i n v e s t i g a t i o n on taxonomy and morophology of t h i s taxon has r e c e n t l y been done by F r y x e l l and Hasle. In a d d i t i o n to t h e i r f i n d i n g s Simonsen(1974) demonstrated the e x i s t e n c e of a c e n t r a l r i n g of seven s t r u t t e d processes as i n Th. symmetrica, but t h i s s t r u c t u r e was not proved i n the present m a t e r i a l s . A cosmopolitan s p e c i e s o c c u r r i n g i n every marine h a b i t a t . In the" study area t h i s s p e c i e s was very common, but never abundant. T j i a i s s i o s i r a e l s a Y e d i i FRYXELL P l . 6, f i g . ~ 4 F r y x e l l 1975, p. 59, f i g s . 1-13 C e l l r e c t a n g u l a r i n g i r d l e view, with a diameter o f 18-5jim. Valves disc-shaped and s l i g h t l y convex. Rows of ar e o l a e arranged i n curved l i n e s forming an e c c e n t r i c a type of p a t t e r n i n g . Areolae about 11 i n 10um. Valve f u r n i s h e d with a marginal r i n g of s t r u t t e d processes, 2 marginal l a b i a t e processes and one c e n t r a l s t r u t t e d process. An i r r e g u l a r l y d i s t r i b u t e d marginal r i n g o f sp i n e s c l o s e to the r i n g o f s t r u t t e d processes i s present. 130 T h i s s p e c i e s was observed only with the SEH. I t i s p o s s i b l e t h a t i t has been i n c l u d e d i n counting Th. d e c i p i e n s . According to F r y x e l l , the presence of the s p e c i e s has been confirmed o n l y i n the Gulf of Hexico. The d i s t r i b u t i o n of t h i s taxon i s s t i l l unknown. In the study area i t was found only i n Juan de Fuca S t r a i t . T h a l a s s i o s i r a n o r d e n s k i o e l d i i CLEVE P i . 7, f i g s . 2a,b Hustetd 1927-30, p. 321, f i g . 157 C e l l s i n g i r d l e view u s u a l l y octangular, with s l i g h t l y rounded corners. Diameter of v a l v e s 13-26nm. P e r v a l v a r a x i s 1/2 the diameter t o almost the same. C e l l s connected i n l o n g f l e x i b l e c h a i n s by a c e n t r a l mucous th r e a d . Valves d i s c - s h a p e d , valve f a c e concave i n the c e n t r a l zone with one s t r u t t e d process, submarginal area b e v e l l e d where a r i n g of s t r u t t e d processes and a l a b i a t e process developed. A l l s t r u t t e d processes t u b u l a r , s t o u t with a r a d i a l d i s t r i b u t i o n . Sows of a r e o l a e r a d i a l or near r a d i a l , a r e o l a e about 20-25 i n 10yim. A b o r e a l or a r c t i c s p e c i e s . One of the most important and abundant n e r i t i c s p e c i e s i n the study area, t h i s s p e c i e s was one of the major p o p u l a t i o n s during s p r i n g and summer, but r a r e l y observed during f a l l and winter. T h a l a s s i o s i r a p a c i f i c a GRAN PI. 7, f i g s . 3a,b Gran & Angst 1931, p. 437, f i g . 12 C e l l s i n g i r d l e view r e c t a n g u l a r , with s l i g h t l y rounded 131 edges. Diameter of v a l v e s 22-46um. C e l l s connected i n long f l e x i b l e c hains by a t h i n mucous thread. Valve d i s c - s h a p e d . Valve f a c e f l a t , b e v e l l e d very c l o s e t o margin. Rows of a r e o l a e curved very s l i g h t l y , o f t e n i n s t r a i g h t l i n e s l i k e the l i n e a t a type of p a t t e r n i n g . Areolae 15-18 i n 10yim. Marginal s t r u t t e d processes i n a r i n g , 4-6 i n 10yum, a s i n g l e s t r u t t e d process i n the c e n t e r of the v a l v e , and one l a b i a t e process i n the marginal zone. A n e r i t i c s p e c i e s . D i s t r i b u t i o n i s probably l i m i t e d to c o a s t a l waters. In the study area t h i s s p e c i e s i s one of major p o p u l a t i o n components i n s p r i n g , but was r a r e l y observed from mid-summer to winter. T h a l a s s i o s i r a polychorda (GRAN) MAKAROVA P l . 8, f i g s . 1a-c Hasle 5 Heimdal 1970, p. 565, f i g . 26 F r y x e l l 1975, p. 66, f i g s . 25-26 Syn.: C o s c i n o d i s c u s polychorda GRAN Hustedt"1927-307 p. 317, f i g . 154 In a d d i t i o n t o pr e v i o u s d e s c r i p t i o n some new i n f o r m a t i o n from SEM micrographs f o l l o w s . More mucous threads(8-14) than i n the o r i g i n a l d e s c r i p t i o n (4-9) i s s u e from s l i m e - p o r e s (not s t r u t t e d t u b u l i ) arranged i n a d i s c o n t i n u o u s c i r c l e . Numerous s p i n u l a e are d i s t r i b u t e d over the v a l v e . Two d i f f e r e n t a r e o l a t i o n s of v a l v e s can be d i s t i n g u i s h e d ; a r a d i a l f a s c i c u l a t e d type and a s t r a i g h t l i n e a t a type. The l a t t e r was d e s c r i b e d as the type s p e c i e s by Gran(1900). T h i s i s a common n e r i t i c s p e c i e s with a wide d i s t r i b u t i o n . 132 In the study area i t was very common during s p r i n g and was observed i n l a r g e numbers a t s t a t i o n 1. T h a l a s s i o s i r a r o t u l a MEUNTER PI.9, f i g . 1a-c Hustedt 1927-30, p. 325, f i g . 161 C e l l s r e c t a n g u l a r i n g i r d l e view, with rounded edges. Diameter of the valve 22-36um. C e l l s connected i n s h o r t c h a i n s by a t h i c k c e n t r a l t h r e a d which i s composed of many f i n e mucous threads. Valves disc-shaped and f l a t , with a very shallow c e n t r a l d e p r e s s i o n . I r r e g u l a r l y shaped a r e o l a e , more than 25 i n 10nm, are present i n the marginal zone. R a d i a l , dichotomously arranged a l v e o l a t e s t r i a e about 30 i n 10jum, are present on the r e s t of the v a l v e . Numerous s t r u t t e d processes are c o n c e n t r a t e d at c e n t e r , e x t r u d i n g mucous thre a d s , and are a l s o i r r e g u l a r l y s c a t t e r e d over the v a l v e , and i n s e v e r a l i r r e g u l a r r i n g s i n marginal zone. S i n g l e l a b i a t e processes are present at some di s t a n c e from the margin. A n e r i t i c s p e c i e s with d i s t r i b u t i o n from temperate t o south temperate waters. In the study area t h i s s p e c i e s i s f a i r l y common and moderately abundant during s p r i n g and e a r l y summer, but was r a r e l y observed during winter. l i l ^ i s s s i o s i r a sp. A. PI.' 8, f i g s . 2a,b Syn.: C o s c i n o d i s c u s l i n e a t u s forma polychorda PERAGALLO P e r a g a l l o 1897-1908, p. 427 133 C e l l s r e c t a n g u l a r i n g i r d l e view and united to form s h o r t c h a i n s by means of s e v e r a l (10-24) mucous threads which are i s s u e d from slime- pores on the v a l v e . Valves d i s c - s h a p e d , convex l i k e watch-glass. Areolae arranged i n s t r a i g h t l i n e s forming a l i n e a t a p a t t e r n , about 20 i n 10um. Diameter of valves observed about 28um. The P e r a g a l l o s were the f i r s t who observed t h i s taxon, but they t r e a t e d i t as a form of the s p e c i e s C o s c i n o d i s c u s l i n e a t u s x p o i n t i n g out t h a t the only d i f f e r e n c e i s the presence o f s e v e r a l mucous threads on the v a l v e s . Compared to T h x £oly_chorda the valve f a c e of t h i s taxon i s h e a v i l y s i l i c i f i e d and no s p i n u l a e can be observed over the v a l v e . These f e a t u r e s of valve s t r u c t u r e as w e l l as the l i n e a t a type of a r e o l a t i o n seem to be s u f f i c i e n t grounds t o separate t h i s taxon from Th.. polychorda . The d i s t r i b u t i o n and abundance of t h i s taxon are unknown, because i t was not p o s s i b l e t o d i s t i n g u i s h i t from T j l i £2iX£h2£<Ia. under the i n v e r t e d microscope. In the study area t h i s taxon was observed at S t a t i o n 2 d u r i n g summer. T h i s new taxon w i l l be named T h a l a s s i o s i r a d e l i c a t u l a when i t i s o f f i c i a l l y p u b l i s h e d . l i i a l a s s i o s i r a sp. B P l . ~ 9 , f i g . 2a-d C e l l s r e c t a n g u l a r i n g i r d l e view, with a diameter from 28-48um. The p e r v a l v a r a x i s i s u s u a l l y 1/2 the diameter. C e l l s are 134 u s u a l l y embedded i n i r r e g u l a r g e l a t i n o u s masses. Many threads can be seen, but the c e l l s r a r e l y connect by a c e n t r a l thread. C h l o r o p l a s t s are s m a l l p l a t e - l i k e and numerous. V a l v e s are d i s c o i d and f l a t . Areolae occur i n e c c e n t r i c a l l y curved l i n e s with about 12 a r e o l a e i n 10um. Small s t r u t t e d processes are present i n a marginal r i n g , about 1.54^im apa r t , and one i n the c e n t e r of v a l v e . The l a b i a t e process i s s i n g l e and l o c a t e d j u s t i n s i d e the marginal r i n g . T h i s s p e c i e s u s u a l l y appeared i n a clump i n which the number of c a l l s v a r i e d from approximately 12 t o 32. The c e l l count of t h i s s p e c i e s was only approximate, due to clumping. T h i s s p e c i e s was f a i r l y ccmmon and moderately abundant i n s p r i n g and was a l s o present i n summer. T h i s taxon w i l l be named T h a l a s s i o s i r a •taylgr-ii • when i t i s f o r m a l l y p u b l i s h e d . T h i s i s d e d i c a t e d t o Dr. F. J . E . T a y l o r . Genus P l a n k t o n i e l l a JGERGENSEN P l a n k t g n i e l l a s o l (RALLICH) SHUETT P i . 10, f i g . 1 Hustedt 1927-30, p. 465, f i g . 259 G e r l o f f 1970, p. 203-234 f i g s . 1-51 Recent r e s e a r c h ( G e r l o f f , 1970; F r y x e l l & Hasle, 1972) on t h i s s p e c i e s has shown t h a t P l a n k t g n i e l l a has marginal s t r u t t e d processes. T h i s evidence supports Simonsen 1 s(1 972) a s s i g n i n g t h i s s p e c i e s to the f a m i l y T h a l a s s i o s i r a c e a e and not to the C o s c i n o d i s c a c e a e . I t i s a t r o p i c a l oceanic s p e c i e s (Smayda, 1958), observed 135 i n the study area o n l y during winter ( i n net sample from S t a t i o n 5). Genus C y c l q t a l l a KUETZING S i c l o t e l l a corata (EHR.) KUETZING PI. To, f i g . 2 Hustedt 1927-30, p. 354, f i g , 183 A f r e s h water s p e c i e s , observed at S t a t i o n 2 d u r i n g summer. C j c l o t e l l a s t r i a t a (KUETZ.) GHUNOW P l . ~ o 7 f i g . 3 Hustedt 1927-30, p. 34 4, f i g . 176 A marine and b r a c k i s h water form. T h i s s p e c i e s was observed f a i r l y ccmmonly durin g f a l l and winter, but was never abundant. Genus Skeletonema GREVILLE Skeletonema costatum (GBEV.) CLEVE Pl."*107 f i g . 4a,b Hustedt 1927-30, p. 311, f i g . 149 Hasle 1973a p. 109-137, f i g s . 1-87 The most thorough morphological study of t h i s s p e c i e s has r e c e n t l y been done by Hasle. She concluded t h a t no d i s t i n c t i o n between s p e c i e s of Skeletonema c o u l d be found based on e l e c t r o n micrographs of v a l v e s t r u c t u r e . However, the s p e c i e s i s , extremely v a r i a b l e i n v a l v e diameter as w e l l as i n the number of*I s t o u t marginal s t r u t t e d processes. A very common n e r i t i c s p e c i e s with world wide d i s t r i b u t i o n i n a l l c o a s t a l waters except i n the A n t a r c t i c . In the study area t h i s s p e c i e s was one of the most abundant s p e c i e s , p a r t i c u l a r l y 136 during s p r i n g and summer. Op to 1 ,900,000 c e l l s per l i t e r were counted. Family C o s c i n o d i s c a c e a e KUETZING •Genus C o s c i n o d i s c u s EHRENBERG-' C o s c i n o d i s c u s a p i c u l a t u s EHRENBERG var. ambigua GRUNOW PlT 1 0 , " f i g . 5 Hustedt 1927-30 , p. 450, f i g . 249 C e l l s d i s c - s h a p e d , s o l i t a r y , with a diameter of 108-I32yum. Valve f a c e s l i g h t l y convex l i k e a watch-glass. R a d i a l rows of a r e o l a e , with i n t e r s p a c e s of v a r i a b l e l e n g t h i n the middle zone. Areolae are p o l y g o n a l , about 4 i n 10um. Center f r e e , h y a l i n e , w i t h i n s m a l l c e n t r a l area. A marine and f o s s i l s p e c i e s . I t was observed at s t a t i o n s 2 , 3 , and 4 , only d u r i n g winter. I t was r a r e i n the study a r e a . C o s c i n o d i s c u s asteromphalus EHRENBERG PlT 1 1 , f i g 7 1 Hustedt 1927 -30 , p. 452 , f i g . 250 A cosmopolitan p l a n k t o n i c s p e c i e s . In the study a r e a t h i s s p e c i e s was observed a t s t a t i o n s 1 , 3 , 4, and 5 , but was not common. Cos c i n o d i s c u s c e n t r a l i s EHRENBERG var. j i a c i f i c a GSAN & ANGST P l . ~ 1 1 , f i g . " 2 Gran 5 angst 1931, p. 446, f i g . 23 Cupp 1943, p. 60, f i g . 24 and p l . 2 Probably an o c e a n i c species(Cupp, 1943). In the study area t h i s v a r i e t y was very common, but a maximum abundance of onl y 800 c e l l s per l i t e r was observed. 1 3 7 C o s c i n o d i s c u s c u r v a l u l u s GRUNOW P l . 11, f i g . 3 Hustedt 1927-30, p. 406, f i g . 214 A n e r i t i c s p e c i e s . Observed o c c a s i o n a l l y d u r i n g winter i n the study area. C o s c i n o d i s c u s a r a n i i GOUGH P l . 11, f i g s . 4a,b Hustedt 1927-30, p. 436, f i g . 237 Cupp 1943, p. 56, f i g . 21 A cosmopolitan p l a n k t o n i c s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y ccmmon, but never abundant. C o s c i n o d i s c u s gj.£as EHRENBERG P l . 11, f i g . 5 Hustedt 1927-30, p. 128, f i g . 254, 256a Simonsen 1974, p. 16 Syn.: C o s c i n o d i s c u s cjicjas var. p r a e t e x t a (JAN.) HUSTEDT Hustedt 1927-30, p. 459, f i g ? 2557 256b Valves 150-184yum i n diameter. Areolae 5-6 i n 10um i n the c e n t r a l r e g i o n and 3-4 i n marginal zone. The valve a r e o l a t i o n of the present m a t e r i a l was r a t h e r s i m i l a r to Hustedt's v a r i e t y p r a e t e x t a . However, i t was concluded t h a t t h i s v a r i e t y cannot be separated from the nominate v a r i e t y . T h i s s p e c i e s i s n e r i t i c to o c e a n i c , o c c a s i o n a l l y observed during f a l l and winter i n the study area. C o s c i n o d i s c u s k u e t z i n g i i A. SCHMIDT Pl.~ 1 1 , ~ f i g 7 6~ Hustedt 1927-30, p. 398, f i g . 209 A common n e r i t i c s p e c i e s . Observed o c c a s i o n a l l y d u r i n g e a r l y summer i n the study area. 138 C o s c i n o d i s c u s m a r g i n a t o - l i n e a t n s A. SCHMIDT PI. 11, f i g . 7 A. Schmidt 1874-1944, p i . 59, f i g . 33 Karsten 1905-7, p. 80, p i . 6, f i g . 6 C e l l s r e c t a n g u l a r i n g i r d l e view. C h l o r o p l a s t s many, rounded p l a t e - l i k e bodies. C e l l s s o l i t a r y . Valves s l i g h t l y convex l i k e a watch-glass, with a diameter of 13^ um. Valve f a c e covered with hexagonal a r e o l a e running i n s t r a i g h t t a n g e n t i a l l i n e s forming a l i n e a t a - t y p e of p a t t e r n . Areolae about 9 i n 10nm. Valve margin wide and f u r n i s h e d with s t r i a e , s t r i a t i o n about 10 i n 10pm, A few l a b i a t e processes are s c a t t e r e d c l o s e to the margin. T h i s s p e c i e s was observed o n l y at s t a t i o n 1 i n December, Cos c i n g d i c u s marg.inatus EHRENBERG Pl7 117 fig7"~8 Hustedt 1927-30, p. 416, f i g . 223 Hendey 1964, p. 78, p i . 22, f i g . 2 An oceanic s p e c i e s with wide d i s t r i b u t i o n . In the study area t h i s s p e c i e s was f a i r l y common during winter and s p r i n g , but never abundant. C o s c i n o d i s c u s normanii GREGORY PI. 12, f i g . 1 C l e v e - E u l e r 1951, p. 38, f i g . 78 Hendey 1964, p. 80 Syn.: Cqs_cinodiscus r o t h i i var. normanii (GREG.) VAN HEURCK Hustedt 1927-30, p7~402, fig.~213 A b e n t h i c diatom a l s o common i n the plankton of the North Sea (Hendey, 1964). In the study area t h i s s p e c i e s was observed a t s t a t i o n 1 only i n January. 139 C o s c i n o d i s c u s obscurus A. SCHMIDT Pl.~12, f i g . 2 Hustedt 1927-30, p. 418, f i g . 224 An o c e a n i c s p e c i e s . T h i s s p e c i e s was o f t e n observed i n the study area, but was never abundant. C o s c i n o d i s c u s g c u l u s - i r i d i s EHRENBERG P lT 12, f i g T 3~ Hustedt 1927-30, p. 454, f i g . 252 Hendey 1964, p. 78, p l , 24, f i g . 1 An oceanic s p e c i e s with world-wide d i s t r i b u t i o n . In the study area t h i s s p e c i e s was f a i r l y common, but never abundant. C o s c i n o d i s g e r f o r a t u s EHRENBERG P l . 12, f i g T 4 Hustedt 1927-30, p. 445, f i g . 244 Cl e v e - E u l e r 1951, p. 66, f i g . 100 A common oceanic s p e c i e s . In the study area t h i s s p e c i e s was r a r e . C o s c i n o d i s c u s r a d i a t u s EHRENBERG P l T ~ l 2 T ~ f i g . 5 Hustedt 1927-30, p. 420, f i g . 225 Hendey 1964, p. 76, p l . 22, f i g . 7 A cosmoploitan s p e c i e s . In the study area t h i s s p e c i e s was one of the commonest s p e c i e s , but not abundant. C o s c i n o d i s c u s r o t h i i (EHR.) GRUNOW . " p i . 12, f i g . 6 Hustedt 1927-30, p. 400, f i g . 211 Cl e v e - E u l e r 1951, p. 58, f i g . 79 A brackish-water s p e c i e s , r a r e i n the study area. 140 C o s c i n o d i scus s t e l l a r i s fiOPER ~Pl7 13, figs7 1a,b Hustedt 1927-30, p. 396, f i g . 207 T h i s s p e c i e s i s considered an ocea n i c species with a world wide d i s t r i b u t i o n i n a l l lat i t u d e s ( H e n d e y , 1964), but Simonsen (1974) suggests t h a t i t shows a r a t h e r n e r i t i c p r e f e r e n c e . In the study area t h i s s p e c i e s was very common, but never abundant. C o s c i n o d i s c u s w a i l e s i l GRAN S ANGST Pl7 12, f i g ? 7 Gran S angst 1931, p. 448, f i g . 25 Cupp 1943, p. 58, f i g . 23 T h i s s p e c i e s i s s i m i l a r t o C A a i ^ a s , but i s d i s t i n g u i s h e d from i t i n that the areol a e i n the former are almost equal i n s i z e , while i n the l a t t e r rows of areolae becomes s m a l l e r towards the c e n t r e . Also s t r o n g , marginal l a b i a t e processes are present i n the former but do not appear i n the l a t t e r . T h i s s p e c i e s seems t o be n e r i t i c . In the study a r e a i t was f a i r l y common during summer and f a l l , but not abundant. Family Hemidiscaceae HENDEY Genus A c t i n o c y c l u s EHRENBERG A c t i n o c y c l u s s u b t i l i s (GREG.) RALFS P i . 7 3 , " " f i g . 8 Hustedt 1927-30, p. 534, f i g . 304 D i s t r i b u t i o n i s wide from t r o p i c a l to temperate areas(mainly i n warm waters). Observed only at s t a t i o n 4. 141 Family H e l i o p e l t a c e a e H. L. SMITH Syn.: A c t i n o d i s c a c e a e SCHUETT • Genus Actinoptychus EHRENBERG ^Sti n o p t y c h u s maculatus GROVE P l . 1 3 , " f i g . 2 Boyer 1926, p. 66 A. Schmidt, a t l a s , p l . 132, f i g . 18 Valve disc-shaped with diameter o f 47yim. Valve f a c e d i v i d e d i n t o 14 s e c t o r s , a l t e r n a t e l y e l e v a t e d and depressed. A s m a l l h y a l i n e area at t h e c e n t e r of the valve c i r c u l a r . S e c t o r s covered with hexagonal a r e o l a e . Areolae somewhat i r r e g u l a r , about 12 i n 10yum. Each depressed s e c t o r f u r n i s h e d with a s t o u t l a b i a t e process. A r a r e s p e c i e s . In the study area i t was once observed at s t a t i o n 3. Actinoptychus s e r a n i u s EHRENBERG P I 7 137 fig7~3 Hendey 1964, p. 95, p l . 23, f i g s . 1,2 Simonsen 1974, p. 23 Syn.: Actinoptychus undulatus (BAILEY) RALFS Hustedt 1927-3 0, p7 475, f i g . 264 A cosmopolitan s p e c i e s . In the study area t h i s s p e c i e s was very common, but never abundant. I S i i f i o i l S k u i solendens (SHADB.) RALFS P l . 13, f i g . 4 Hustedt 1927-30, p l . 478, f i g . 265 Hendey 1964, p. 95, p l . 22, f i g . 1 A l i t t o r a l s p e c i e s . Not common i n the study area. 142 Genus Ara c h n o i d i s c u s DSANE Arac h n o i d i s c u s eh r e n b e r c j i i BAILEY PI. 13, f i g . 5 Hustedt 1923-30, p. 471, f i g . 262 Cupp 1943, p. 66, f i g . 28, p i . 4, f i g . 1 A l i t t o r a l s p e c i e s , o f t e n found i n plankton. In the study area t h i s s p e c i e s was observed o n l y o c c a s i o n a l l y . Genus Auiacodiscus EHRENBERG Aula c o d i s c u s k i t t o n i i A8N0TT PI. 13, f l g 7 6 Hendey 1964, p. 98, p i . 22, f i g . 5 A r a r e probably l i t t o r a l s p e c i e s . I t was observed only at s t a t i o n s 4 and 5. Family Asterolampraceae H. L. SMITH Genus Asteromphalus EHRENBERG Asteromphalus h e p t a c t i s (BREB.) BALES PlT 13, f i g . 7 Hustedt 1927-30, p. 494, f i g . 277 Hendey 1964, p. 96, p i . 24, f i g . 5 A cosmopolitan, oceanic form. I t was observed o n l y a t s t a t i o n 5. Suborder R h i z o s o l e n i i n e a e Family R h i z o s o l e n i a c e a e PETIT Genus R h i z o s o l e n i a {EHR.) BRIGHTWELL R h i z o s o l e n i a a l a t a BRIGHTWELL PI. 14, f i g . 1 Hustedt 1927-30, p. 600, f i g . 344 Cupp 1943, p. 90, f i g . 52-a An oceanic and temperate s p e c i e s , not common i n the study 143 area. Rili2°solenia a l a t a BRIGHT8ELL forma c u r v i r o s t r i s GRAN P l T 14, f i g . 2 Hustedt 1927-30, p. 602, f i g . 347 Cupp 1943, p. 93, f i g . 52-d An oceanic form, observed only during winter i n the study a r e a . R h i z o s o l e n i a c a l c a r - a v i s E. SCHULTZE PI. 17~fig7~2 Hustedt 1927-30, p. 592, f i g . 339 Cupp 1943, p. 89, f i g . 51 An oce a n i c , warm water s p e c i e s . Rare i n the study area. R h i z o s o l e n i a d e l i c a t u l a CLEVE ~P1. 1 4 , " f i g . 3 Hustedt 1927-30, p. 577, f i g . 328 Cupp 1943, p. 83, f i g . 44 A n e r i t i c form, common i n the study area and abundant during e a r l y summer. R h i z o s o l e n i a f r a g i l i s s i m a BERGON PI. 14, f i g T 4 Hustedt 1927-30, p. 571, f i g . 324 Cupp 1943, p. 80, f i g . 41 A n e r i t i c , north temperate t o b o r e a l s p e c i e s . Not common i n the study area. R h i z o s o l e n i a hebetata (BAIL.) GRAN forma semispina (HENSEN) GRAN P i . 14, f i g . 5 Hustedt 1927-30, p. 592, f i g . 338 Cupp 1943, p. 88, f i g . 50-b 144 An oce a n i c , warm water s p e c i e s . Very common i n the study area, but never abundant. S h i z o s o l e n i a s e t i g e r a BRIGHTWELL Pl7 14," f i g T 6 Hustedt 1927-30, p. 588, f i g . 336 Cupp 1943, p. 88, f i g . 49 A n e r i t i c , temperate s p e c i e s . Very common i n the study area, but never abundant. Genus Ditylum BAILEY Ditylum b r i g h t w e l l i i (WEST.) GEUNOW P l . 14, f i g . 7 Hustedt 1927-30, p. 784, f i g . 457 Cupp 1943, p. 148, f i g s . 107-a,b A n e r i t i c , temperate s p e c i e s . In the study a r e a t h i s s p e c i e s was very common and formed one of the major p o p u l a t i o n s d u r i n g l a t e summer and e a r l y f a l l . Genus Guina r d i a H, PERAGALLO G u i n a r d i a f l a c c i d a (CASTR.) H. PERAGALLO P l . 14,""figs. 8a,b Hustedt 1927-30, p. 562, f i g . 332 Cupp 1943, p. 78, f i g . 40 A n e r i t i c , temperate t o t r o p i c a l s p e c i e s . Rare i n the study area. Genus Lithodesroium EHRENBERG Lithodesmium undulaturn EHRENBERG P l . 147~fig7 9 Hustedt 1927-30, p. 789, f i g , 461 Cupp 1943, p. 150, f i g . 108 145 A n e r i t i c , temperate s p e c i e s . Rare i n the study a r e a . Family Chaetoceraceae H. L. SMITH Genus Chaetoceros EHRENBERG Chaetoceros a f f i n i s LAUDER p l . ~ 1 4 , ~ f i g . 10 Hustedt 1927-30, p. 695, f i g . 396 Cupp 1943, p. 125, f i g . 73-a Brunei 1962, p. 114, p l . 27, f i g . 1 A n e r i t i c , temperate s p e c i e s . In the study area i t was very common and f a i r l y abundant during summer. Chaetoceros a f f i n i s LAUDER var, w i l l e i (GRAN) HUSTEDT P l . 15, f i g . 1 Hustedt 1927-30, p. 697, f i g . 398 Cupp 1943, p. 126, f i g . 78-c Brunei 1962, p. 116, p l . 27, f i g . 2 T h i s v a r i e t y was f a i r l y common only during summer. Chaetoceros b r e y i s SCHUETT P l . ~ l 7 f i g . 3 Hustedt 1927-1930, p. 707, fi g . 4 0 3 Brunei 1962, p. 120, p l . 27, f i g 3; p l . 29, f i g s . 1,2 Cupp 1943, p. 129, f i g . 82 A n e r i t i c , warm water s p e c i e s . In the study area i t was very common and f a i r l y abundant, but only i n summer. Chaetoceros ceratosporum OSTENFELD ~ P 1 . ~ T 6 , figT 1~ Hustedt 1927-30, p. 760, f i g . 442 Hendey 1964, p. 138, p l . 17, f i g . 7 A n e r i t i c s p e c i e s . Rare i n the study area. 146 Chaetoceros c i n e t u s GRAN P I . " 7 5 , " f i g . 2 Hustedt 1927-1930, p. 684, f i g . 388,389 Cupp 1943, p. 142, f i g . 98 A n e r i t i c south temperate s p e c i e s . In the study area t h i s s p e c i e s was not common. Chaetoceros compressus LAUDER P i . " 5 , f i g ? 3 Hustedt 1927-30, p. 584, f i g s . 388-389 Cupp 1943, p. 119, f i g . 74 Brunei 1962, p. 110, p i . 25, f i g s . 1-4 A cosmopolitan n e r i t i c , b o r e a l to temperate s p e c i e s . In the study area t h i s s p e c i e s was very common. Sometimes abundant, but i n most cases i t was present i n moderate numbers only, Chaetoceros c o n c a y i c o r n i s MANGIN PI. 15, f i g ? 4 Hustedt 1927-30, p. 665, f i g . 376 Cupp 1943, p. 109, f i g . 66 Brunei 1962, p. 90, p i . 12, f i g s . 1-5 An oceanic, b o r e a l - a r c t i c s p e c i e s . T h i s s p e c i e s was f a i r l y common i n the study area except i n summer, but was not abundant. Chaetoceros c o n s t r i c t u s GRAN PI. 15, f i g . 5 Hustedt 1927-30, p. 694, f i g . 395 Cupp 1943, p. 12 2, f i g . 76 Brunei 1962, p. 112, p i . 26, f i g s . 1-2 A n e r i t i c , c o l d temperate s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y common but was not abundant. Chaetoceros c o n v o l t u s CASTRACANE 147 PI. 15, f i g . 6 Hustedt 1927-30, p. 668, f i g . 378 Cupp 1943, p. 110, f i g , 67 Brunei 1962, p. 91, p i . 13, f i g . 1 An oc e a n i c , a r c t i c and b o r e a l form. In the study area t h i s s p e c i e s was common, but never abundant. Chaetoceros danicus CLEVE PI. 1 5 , ~ f i g . 7 Hustedt, 1927-30, p. 659, f i g . 373 Cupp 1943, p. 109, f i g . 6 5 Brunei 1962, p. 88, p i . 11, f i g s . 1-6 A n e r i t i c , north temperate s p e c i e s . Rare i n the study area. Chaetoceros d e b i l i s CLEVE P l . ~ 5 , f i g . 8 Hustedt 1927-30, p. 740, f i g . 428 Brunei 1962, p. 130, p i , 32, f i g s . 1-6 A n e r i t i c , c o l d water s p e c i e s . I t was one of the most important s p e c i e s and one of major populations during s p r i n g and e a r l y summer. Chaetoceros d e c i p i e n s CLEVE PI. 16, f i g T 2 Hustedt 1927-30, p. 675, f i g . 383 Cupp 1943, p. 115, f i g . 70-A, B Brunei 1962, p. 99, p i . 21, f i g s . 1-4; p i . 22, f i g s 1-5 A cosmopolitan n e r i t i c , a r c t i c - b o r e a l s p e c i e s . In the study area t h i s s p e c i e s was very common and moderately abundant except dur i n g winter and e a r l y s p r i n g . Chaetoceros diadema (EHR.) GRAN PI. 17, f i g . 2 148 Brunei 1962, p. 122, p i . 27, f i g . 4; p i . 30, f i g s . 1-5 Hendey 1964, p. 128, p i . 10, f i g . 1 Syn.; Chaetoceros subsecundus (GRUN.) HUSTEDT Hustedt 1927-30, p7~709, f i g . 404 Cupp 1943, p. 130, f i g . 83 Hendey 1974, p. 285 A n e r i t i c s p e c i e s with a wide d i s t r i b u t i o n i n temperate seas. In • the study area t h i s s p e c i e s was common d u r i n g summer and becames one of major p o p u l a t i o n s i n J u l y and August. Chaetoceros didymus EHRENBERG PI. 16, f i g . 3 Hustedt 1927-30, p. 688, f i g . 390 Cupp 1943, p. 121, f i g . 75-a A n e r i t i c , s p e c i e s with a wide d i s t r i b u t i o n i n temperate seas. In the study area i t was very common, and moderately abundant except during winter. Chaetoceros d i f f i c i l i s CLEVE PI. 1, f i g . ~ 4 Hustedt 1927-30, p. 715, f i g . 408 Cupp 1943, p. 132, f i g . 86 A n e r i t i c s p e c i e s , common and f a i r l y abundant dur i n g s p r i n g and summer. I t was a l s o observed i n l a r g e numbers a t s t a t i o n 2 i n June. Chaetoceros i n g o l f i a n u s OSTENFELD Pl.~16, f i g T 4 Hustedt 1927-30, p. 733, f i g . 423 Brunei 1962, p. 127, p i . 31, f i g s . 3-4 A n e r i t i c s p e c i e s . Not common i n the study area. Chaetoceros l a c i n i o s u s SCHUETT PI. 7l7"~figT~5 149 Hustedt 1927-30, p. 701, f i g . 401 Cupp 1943, p. 128, f i g . 80 Brunei 1962, p. 118, p l . 28, f i g s . 1-5; p l . 29, f i g . 5; p l . 40, f i g . 4 A n e r i t i c s p e c i e s with a wide d i s t r i b u t i o n i n temperate seas. In the study area i t was f a i r l y common and moderately abundant during summer and f a l l . Chaetoceros l o r e n z i a n u s GBUNOS P l . T?7 f i g T 6 Hustedt 1927-30, p. 679, f i g . 385 Cupp 1943, p. 118, f i g . 71 Brunei 1962, p. 105, p l . 18, f i g s . 1-4; p l . 19, f i g s . 1-4 A n e r i t i c s p e c i e s with wide d i s t r i b u t i o n i n t r o p i c a l and temperate seas. In the study area i t was common and moderately abundant during s p r i n g and summer. Chaetoceros 2§eudocrinitus OSTEN.FELD P l . 167 f i g T 7 Hustedt 1927-30, p. 733, f i g . 422 Hendey 1964, p. 132, p l . 14, f i g . 2 A n e r i t i c s p e c i e s with a wide d i s t r i b u t i o n . Not ve r y common i n the study area. Chaetoceros r a d i c a n s SCHUETT P l . ~ 6 , f i g . 8 Hustedt 1927-30, p. 746, f i g . 431 Cupp 1943, p. 141, f i g . 97 Brunei 1962, p. 132, p l . 33, f i g s . 1-4; p l . 34, f i g s . 1-2 A cosmopolitan, n e r i t i c s p e c i e s . In the study area t h i s s p e c i e s was very common and became very abundant duri n g s p r i n g 150 and summer. Chaetoceros s i m i l i s CLEVE P l . TT7 f i g . 9 Hustedt 1927-30, p. 720, f i g . 411 Cupp 1943, p. 135, f i g . 90 Brunei 1962, p. 125, p l . 31, f i g s . 1-2 A n e r i t i c s p e c i e s with a wide d i s t r i b u t i o n i n c o l d temperate seas. In the study area t h i s s p e c i e s was very common and moderately abundant from mid-spring t o e a r l y f a l l . Chaetoceros simplex OSTENFELD P l . T, fig", 5 Hustedt 1927-30, p. 755, f i g . 437 Hendey 1964, p. 137, p l . 19, f i g . 2 A n e r i t i c s p e c i e s , observed i n the study a r e a only i n March. Chaetoceros s o c i a l i s LAUDER P l . ~ 7 , f i g . 1 Hustedt 1927-30, p. 751, f i g . 435 Cupp 1943, p. 143, f i g . 100 Brunei 1962, p. 135, p l . 26, f i g . 3; p l . 29, f i g s . 3-4; p l . 36, f i g s . 1-4 p l . 37, f i g s . 1-3 A n e r i t i c , b o r e a l - a r c t i c s p e c i e s . In the study area t h i s s p e c i e s was very common and moderately abundant except d u r i n g winter. Chaetoceros s u b t i l i s CLEVE ~P1.~1, figT 6 Hustedt 1927-30, p. 723, f i g . 413 Hendey 1964, p. 130, p l . 10, f i g . 2 A n e r i t i c s p e c i e s . Rare i n the study area. 151 Chaetgcerqs t e t r a s t i c h o n CLEVE PI. 2~ fig7~1 Hustedt 1927-3 0, p. 657, f i g . 371 Cupp 1943, p. 108, f i g . 63 An oce a n i c , t r o p i c a l and south temperate s p e c i e s . Rare i n the study area. Chaetoceros y a n h e u r c k i i GRAN P l . ~ 7 7 f i g 7 3 Gran S Angst 1931, p. 476, f i g . 60 Cupp 1943, p. 123, f i g . 77 A n e r i t i c s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y ccmmon and moderately abundant only i n August. However, counts were probably confused with Ch. c o n s t r i c t u s , because the two s p e c i e s can be d i s t i n g u i s h e d only by the s t r u c t u r e of the r e s t i n g spore (Gran & Angst, 1931; Cupp, 1943) . Genus Ea c t e r i a s t r u m SHADBOLT Bacteria s t r u m d e l i c a t u l u m CLEVE P I . " 1 7 7 flg« 5 Hustedt 1927-30, p. 612, f i g . 613 Cupp 1943, p. 96, f i g . 55 An oceanic, temperate s p e c i e s . Not common i n the study area. Suborder B i d d u l p h i i n e a e Family Hemiaulaceae HEIBERG Genus Hemiaulus EHRENBERG Hemiaulus s i n e n s i s GREVILLE Pl7"T, f i g . 7 152 Husteat 1927-30, p. 815, f i g . 519 Cupp 1943, p. 168, f i g . 119 A n e r i t i c s p e c i e s , u s u a l l y of t r o p i c a l and s u b t r o p i c a l d i s t r i b u t i o n i n a l l seas. Bare i n the study area. Genus C e r a t a u l i n a H. PERAGALLO j Q ^ I ^ t a u l i n a b e r g o n i i H. PERAGA110 P l . 17, f i g . 5 Hustedt 1927-30, p. 869, f i g . 517 Cupp 1943, p. 167, f i g . 167 Simonsen 1974, p. 33 Syn.; C e r a t a u l i n a p e l a g i c a (CLEVE) HENDEY Hendey 1937, p.""279 A cosmopolitan n e r i t i c s p e c i e s with a warm water pre f e r e n c e . In the study area t h i s s p e c i e s was common and moderately abundant during summer. Genus EucajBgia EHRENBERG Eucampia zqdjacus EHRENBERG P l . 2, f i g . 2 Hustedt 1927-30, p. 772, f i g . 451 Cupp 1943, p. 145, f i g . 103 A cosmopolitan n e r i t i c s p e c i e s . In the study .area t h i s s p e c i e s was common and one of most important s p e c i e s i n August. Family Biddulphiaceae KUETZING T h i s i s one of the l a r g e s t f a m i l i e s i n the C e n t r a l e s comprising a number o f q u i t e d i s s i m i l a r g e n e r i c groups, so t h a t the placement of some genera of t h i s f a m i l y can c r e a t e some con f u s i o n even with new i n f o r m a t i o n from the SEM. Ross and 153 Sims (1971) have shown t h a t the f i n e l y p o r u l a t e d bosses of f i n e pores i n the valve angles of many Biddulphiaceae s p e c i e s are only the valve s t r u c t u r e reduced i n s i z e , and conclude t h a t the members pos s e s s i n g o c e l l i belong to the f a m i l y Eupodiscaceae. They suggest t h a t genera of the f a m i l y should separated on the b a s i s of poroid or a r e o l a t e d v a l v e s . However, t h i s s e p a r a t i o n does not seem j u s t i f i e d , Simonsen (1974) having pointed out t h a t i t i s a q u a n t i t a t i v e c r i t e r i o n . D i s a g r e e i n g with Ross and Sims, Simonsen p r e f e r s t o keep the b i p o l a r genera separate from the m u l t i p o l a r genera. Though Simonsen's point i s w e l l taken h i s s e p a r a t i o n does not seem j u s t i f i e d e i t h e r , because i t confuses the o c e l l a r ( T r i c e r a t i u m antediluvianum ) and the pseudo-o c e l l a r ( Tri3.2aiM2 )• In my o p i n i o n the best arrangement of t h i s group was made by Hendey (1964). He placed a number of the complex b i d d u l p h o i d group i n t o the genera Biddulphia,, T r i c e r a t i u m and T r i q o n i u m x using as h i s b a s i s the d e t a i l e d valve s t r u c t u r e , the presence o f va l v e s p i n e s , and the l a b i a t e processes (valve s p i n e s i n h i s term). According t o Hendey, i n Buddulphia valves are b i p o l a r , e l l i p t i c a l , t r i a n g u l a r or p o l y g o n a l . Angles of the valve have a process, with e i t h e r l o n g narrow or b l u n t l y c o n i c a l horns; or r a i s e d bosses with f i n e pores. The valve s u r f a c e i s u s u a l l y c o a r s e l y punctate, the punctae being s c a t t e r e d or arranged sub-r a d i a l l y and f u r n i s h e d with two or more s p i n e s . In T r i c e r a t i u m the v a l v e o u t l i n e i s t r i a n g u l a r or po l y g o n a l . The processes i n the angles are s t i l l h o r n - l i k e , though u s u a l l y s h o r t e r and s t o u t e r than i n the B i d d u l p h i a s p e c i e s . The valve s u r f a c e i s 154 covered with a r e g u l a r hexagonal a r e o l a t i o n and t h e r e are no co s t a e . Small s p i n e s a re u s u a l l y present on the valve s u r f a c e and a t the margin. In Trigonium the t r i a n g u l a r or p o l y g o n a l o u t l i n e remains, but the angles are rounded and seldom much produced; no r a i s e d process or h o r n - l i k e process appears. The angle s u r f a c e i s f u r n i s h e d with very f i n e pores. The va l v e s u r f a c e i s covered with a p o l y g o n a l a r e o l a t i o n which i s u s u a l l y arranged i n r a d i a t i n g l i n e s . Spines are u s u a l l y absent. The above c h a r a c t e r i s t i c s are u s e f u l i n the d i s t i n c t i o n of bi d d u l p h o i d genera. However, i t i s obvious t h a t much more i n f o r m a t i o n , as Simonsen has s a i d (1974), w i l l be needed t o a r r i v e a t b e t t e r concept of the genera and s p e c i e s . Genus jBiddulphia GRAY B i d d u l p h i a antediluvianum (EHR.) VAN HEURCK P l . 17, f i g . 6 Hendey 1964, p. 102 Syn.: T r i c e r a t i u m antediluvianum (EHR.) GRUNOM Hustedt~1927-30, p. 810, f i g . 472 A l i t t o r a l s p e c i e s . Not common i n the study area. B i d d u l p h i a a u r i t a (LYNGB.) BREBISSON & GODEY P l 7 ~ 1 7 , ~ f i g . 7 Hustedt 1927-30, p. 846, f i g . 501 Cupp 1943, p. 161, f i g s . 112-a(1)-(3) A cosmopolitan n e r i t i c s p e c i e s . In the study area t h i s s p e c i e s was common, but never abundant. B i d d u l p h i a dubia (BRIGHT.) CLEVE Pl.~17, f i g . 8 155 Cupp 1943, p. 164, f i g . 114 A n e r i t i c warm water s p e c i e s . Rare i n the study a r e a . B i d d u l p h i a l o n g i c r u r i s GREVILLE PlT 7 7 , f i g . ~ 9 Gran 5 Angst 1931, p. 491, f i g . 75 Cupp 1943, p. 154, f i g s . 111-a(1)-{3) A n e r i t i c , temperate to s u b t r o p i c a l s p e c i e s . In the study area t h i s s p e c i e s was r e l a t i v e l y common, e s p e c i a l l y during summer. B i d d u l p h i a l o n g i c r u r i s GREVILLE var. h y a l i n a (SCHROEDER) CUPP ~ P 1 . " 7 7 , f i g . 10 Cupp 1943, p. . 157, f i g s . 111 B(1)-{3) T h i s v a r i e t y i s a n e r i t i c , north temperate form. Not common i n the study area. B i d d u l p h i a obtusa (KUETZ.) RALFS PI. 787~fig. 1 C l e v e - E u l e r 1951, p. 119, f i g . 258 Hendey 1964, p. 104 Syn.; B i d d u l p h i a a u r i t a (LYNGB.) BREBISSON S GODEY var. obtusa (KUETZ.) HUSTEDT Hustedt 1927-30, p. 848, f i g . 502 A l i t t o r a l s p e c i e s , but common i n plankton. In the study area t h i s s p e c i e s was f a i r l y ccmmon during spring and summer. B i d d u l p h i a sp. A. P i . 18, f i g s . 2a,b F r u s t u l e s r e c t a n g u l a r , with prominent processes i n g i r d l e view. P e r v a l v a r a x i s 63-69um. C e l l s u n i t e d i n s t r a i g h t c h a i n s by 4 156 mucous pads at c o r n e r s . G i r d l e zone s h a r p l y d i f f e r e n t i a t e d from the valve zone and r i g h t - a n g l e d . G i r d l e i s f i n e l y p o r o i d , poroid s t r i a e i n annular d e c u s s a t i n g rows; about 14 puncta i n 10yim. Valve e l l i p t i c a l or l a n c e o l a t e . A p i c a l a x i s of, v a l v e 16yum. Apices f u r n i s h e d with s h o r t blunt processes. Poroid a r e o l a e on the v a l v e s u r f a c e with rows running p a r a l l e l t o p e r v a l v a r a x i s , about 13 a r e o l a e i n 10jfrm. Numerous s p i n u l a e d i s t r i b u t e d over the whole v a l v e s u r f a c e . Valve face f l a t , with many l o n g , t h i c k spines which are connected to the valve s u r f a c e of the. adjacent c e l l . Valve mantle deep. Only f o u r specimens of t h i s s p e c i e s was observed o n l y under the SEM. V a l v e / g i r d l e s t r u c t u r e s are s i m i l a r to Bj. granulata.. A remarkable c h a r a c t e r i s t i c was l o n g , t h i c k s p ines on the valve f a c e which resemble the occluded processes but more s t r a i g h t t u b u l a r s t r u c t u r e . Mucous pads between the two h o r n - l i k e processes can be c l e a r l y seen i n the SEM micrographs. T h i s taxon occurred i n the net sample i n August, 1972 at s t a t i o n 3. T h i s new taxon w i l l be named B i d d u l p h i a po 1 yacanth-a when i t i s p u b l i s h e d . Genus Trigonium CLEVE Triaonium arcticum (BRIGHTW.) CLEVE Pl7~18"7 f i g . 3 Hendey 1964, p. 109 syn.: T r i c e r a t i u m arcticum BRIGHTHELL Hustedt 1927-30, p7 816, f i g . 479 A n e r i t i c s p e c i e s . Not common i n the study area. 157 Trigonium sp, A P l . 18, f i g s . 4a,b C e l l s r e c t a n g u l a r in g i r d l e v i e s . Valves t r i a n g u l a r , s i d e s s l i g h t l y convex, with l e n g t h of 105-142pm between angles. Angles rounded, not much produced i n t o processes. Valve s u r f a c e s l i g h t l y r a i s e d i n the c e n t r a l zone. Rows of a r e o l a e r a d i a l with an i r r e g u l a r arrangement i n the c e n t r a l zone. P o l y g o n a l a r e o l a e are s m a l l at the c e n t e r , about 5 i n 10^im, i n c r e a s i n g i n s i z e at h a l f the r a d i u s (about 3 i n 10pm), a f t e r which they decrease again. Many l a b i a t e processes (2-4 i n 10um) s c a t t e r e d mainly i n the middle zone of the valve. Angles of valve f u r n i s h e d with bosses covered by very f i n e pores. T h i s v a r i e t y was observed o n l y at s t a t i o n s 4 and 5 d u r i n g s p r i n g . T h i s new taxon w i l l be named as Trigonium a r c t i c u m var. acantha when i t i s o f f i c i a l l y p u b l i s h e d . Genus Isthmia AGARDH Isthmia nervosa KUETZING ~Pl7~19, f i g . 1 Hustedt 1927-30, p. 866, f i g . 515 Cupp 1943, p. 166, f i g . 116 A l i t t o r a l s p e c i e s , which occurred i n p l a n k t o n as a t y c h o p e l a g i c form. Rare i n the study area. 158 Order Pennales Suborder Araphidineae Family Diatomaceae DUMORTIER Genus Rhabdonema KUETZING Rhabdonema adriaticuro KUETZING ~Pl7~?9, f i g . 2 Hustedt 1931-59, p. 23, f i g . 552 Hendey 1964, p. 172 A l i t t o r a l s p e c i e s . Rare i n the study area. Rhabdonema arcuatum (LYNGB.) KUETZING ~P1. 197 f i g . 3 C l e v e - e u l e r 1953a, p. 6, f i g . 294 Hendey 1964, p. 172, p l . 35, f i g s . 10-12 A l i t t o r a l s p e c i e s u s u a l l y found as an epiphyte on marine algae. O c c a s i o n a l l y observed i n the study area. , Genus Grammatophora EHRENBERG Grammatophora angulosa EHfiENBERG P l . 197 f i g . " 4 Cupp 1943, p. 174, f i g . 124 Hustedt 1931-59, p. 45, f i g . 573 Hendey 1964, p. 171 A l i t t o r a l , temperate s p e c i e s , o f t e n found i n plankton. O c c a s i o n a l l y observed i n the study area. GramroatpBhora marina (LYNGB.) KUETZING P l . ~19~7 f i g . 5 Cupp 1943, p. 174, f i g . 125-a Hustedt 1931-59, p. 43, f i g . 569 A common l i t t o r a l s p e c i e s , very o f t e n present i n plankton. In the study area t h i s was common and was moderately abundant i n 159 Hay. Grammatophora maxima GRUNOW P l . 19, f i g . 6 Cl e v e - E u l e r 1953a, p. 12, f i g . 305b Hustedt 1931-59, p. UH, f i g . 572 A common l i t t o r a l s p e c i e s . Bare i n the study area, •Genus Liemophora AGARDH Licmophora a b b r e y i a t a AGARDH Pl.~19, f i g . 7 Cl e v e - E u l e r 1953a, p. 17, f i g . 318 Hustedt 1931-59, p. 66, f i g . 590 A marine l i t t o r a l s p e c i e s , o f t e n found i n plankton. F r e g u e n t l y found i n the study area. Licmophora ehrenbercjii (KOETZ.) GRDN05? P l . "19, f i g . 8 C l e v e r - E u l e r 1953a, p. 18, f i g . 319a,b Hustedt 1931-59, p. 70, f i g . 593 A l i t t o r a l s p e c i e s , u s u a l l y e p i p h y t i c on al g a e . Rare i n the study area. Licmophora paradoxa (LYNGB.) AGARDH P l . ~ 9 , ~ f i g . 9 Cl e v e - E u l e r 1953a, p. 18, f i g s . 322a, a-c Hustedt 1931-59, p. 76, f i g . 605 A l i t t o r a l s p e c i e s . Rare i n the study area. Genus S t r i a t e l l a AGARDH 160 S t r i a t e l l a d e l i c a t u l a (KUETZ.) GRUNOW PI. 2, fig7 3 Hustedt 1931-59, p. 33, f i g . 560 Hendey 1964, p. 161 A l i t t o r a l s p e c i e s , sometimes found i n the n e r i t i c plankton. Rare i n the study area. Genus Tabe11aria EHRENBERG T a b e l l a r i a f e n e s t r a t a (LYNGB.) KUETZING PI. 2, f i g . ~ 4 C l e v e - E u l e r 1953a, p. 10, f i g s . 303a-c Hustedt 1931-59, p. 26, f i g . 554 A freshwater s p e c i e s , a l l o c h t h o n o u s i n the study area. I t was f a i r l y common at s t a t i o n s 2 and 3 during summer, but never abundant. T a b e l l a r i a f e n e s t r a t a (LYNGB.) KUETZING var. a s t e r i o n e l l o i d e s GRUNOW PI. 1 9 7 f i g . 1 0 C l e v e - E u l e r 1953a, p. 10, f i g . 303h, i Hustedt 1931-59, p. 28, f i g . 556 L i k e a nominate taxon a freshwater p l a n k t o n i c form. T h i s v a r i e t y was al l o c h t h o n o u s i n the study area and of t e n observed a t s t a t i o n 2 durin g summer. T a b e l l a r i a f e n e s t r a t a (LYNGB.) KUETZING var. intermedia GRUNOW PI. 19, f i g . 11 Cl e v e - E u l e r 1953a, p. 10, f i g s . 303a, a-c Hustedt 1931-59, p. 27, f i g . 555 A freshwater p l a n k t o n i c form. T h i s v a r i e t y i s a l l o c h t h o n o u s i n the study area and was only observed a t s t a t i o n 2. Rare. 161 • Genus Plaaioc|ra|ima GREVILLE Plagiograroffla vanheurckii GRUNOW ~P1. 2, fig7~5~ Cupp 1943, p. 179, f i g . 129 Hustedt 1931-59, p. 112, f i g . 638 A marine planktonic diatom, probably i n warm coastal waters. This species was observed at stations 3 and 5 during spring, and moderately abundant at station 5 i n A p r i l . Genus Rhaphoneis EHRENBERG iMEiJoSeif. amphiceros ERR EN BERG ~P1. 19, f i g . 12 Hustedt 1931-59, p. 174, f i g . 680 Hendey 1964, p. 154, p i . 26, f i g s . 1-4 A marine and brackish-water species with wide d i s t r i b u t i o n . Simonsen (1974) considered t h i s species as a tychopelagic species l i k e Paralia sulcata , because t h i s species and Rh, s u r i r e l l a are almost always encountered i n coastal plankton. In the study area t h i s species was f a i r l y common, but not abundant. Rhaphoneis s u r i r e l l a (EHR.) GRUNOW ~Pl7~19, f i g . 13 Hustedt 1931-59, p. 173, f i g s . 679, a-c Hendey 1964, p. 155, p i . 26, f i g s . 11-13 A cosmopolitan benthic and tychopelagic species. In the study area t h i s species was f a i r l y common during spring, but was not abundant. Genus F r a g i l a r i a LYNGBYE F r a g i l a r i a capucina DESHAZIERE ~Pl7~19,~fig. 14 162 Hustedt 1931-59, p. 144, f i g s . 659 a-c Hendey 1964, p. 15o A f r e s h water s p e c i e s , but f r e q u e n t l y found i n n e r i t i c p lankton. Not very common i n the study area. F r a g i l a r i a c r o t o n e n s i s KITTON ~P1. 19,~fig.~15 Cupp 1943, p. 181, f i g . 131 Hustedt 1931-59, p. 143, f i g . 658 A brackish-water s p e c i e s found near shore. Not very common i n the study area. F r a g i l a r i a i s l a n d i c a GRUN08 Pl7~19, f i g . 16 Hustedt 1931-59, p. 146, f i g . 660 Hendey 1964, p. 153 A n e r i t i c s p e c i e s i n b o r e a l waters. In the study area t h i s s p e c i e s was observed at s t a t i o n s 4 and 5 during e a r l y s p r i n g . F r a g i l a r i a s t r i a t u l a LYNGBYE PI. 19, f i g . 17 Gran & Angst 1931, p. 495, f i g . 81 Hustedt 1931-59, p. 150, f i g . 663 A n e r i t i c p l a n k t o n i c s p e c i e s . In the study area t h i s s p e c i e s i s f a i r l y common during s p r i n g . Never abundant. Genus Synedra EHRENBERG Synedra acus KUETZING ~P1. 20, f i g . 1 Hustedt 1931-59, p. 201, f i g . P a t r i c k and Reimer 1966, p. 135, p i . 5 f i g . 1 163 A freshwater s p e c i e s . Observed on l y a t s t a t i o n 2 i n May. Synedra i s a b e l a e PATRICK var. Pl.~"20, f i g . 2 P a t r i c k 1970, p. 499, C e l l l i n e a r and narrow l i n e a r , t a p e r i n g t o the narrow C e n t r a l area absent, s t r i a e l e n g t h , 140pra. Breadth 3.5pm. nominate s p e c i e s i s c e l l s i z e . A freshwater s p e c i e s obse i s a b e l a e f i g . 2 i n g i r d l e view. Valve narrow and a p i c e s . A x i a l area very narrow, f a i n t , about 14 i n 10yum. Valve The only d i f f e r e n c e from the ved o n l y a t s t a t i o n 1 i n May. Synedra k e r g u e l e n s i s HEIDEN £ KOLBE Pl.~20, f i g . 3 fleiden S Kolbe 1928, p. 560, p l . 5, f i g . 111 Valve l i n e a r - l a n c e o l a t e ; narrowed toward the b l u n t l y rounded a p i c e s . A x i a l area very narrow and s t r a i g h t . C e n t r a l area h y a l i n e , l a r g e and broad, about 1/5 the l e n g t h . S t r i a e f a i n t , about 16 i n 10nm. Valve l e n g t h 92/pm, breadth 8.5ytim. Apparently a r a r e n e r i t i c s p e c i e s . Observed only a t s t a t i o n 5 i n October. Synedra ulna (NITZ.) EHRENBERG P l . 20, f i g . 4a,b Hustedt 1931-59, p. 195, f i g s . 691 a-c P a t r i c & Reimer 1966, p. 148, p l . 7, f i g s . 1-2 A cosmopolitan f r e s h water s p e c i e s . This s p e c i e s was allochthonous i n the study area and was f a i r l y common du r i n g 164 summer and f a l l , but never abundant. Synedra ulna (NITZ.) EHRENBERG var. ajiPhirhynchus (EHR.) GRUNOW ~Pl7 20, f i g . 5 Hustedt 1931-59, p. 198, f i g . 691c P a t r i c k S Reimer 1966, p. 149, p i . 7, f i g s . 6-7 A very common freshwater form with a wide d i s t r i b u t i o n , observed only at s t a t i o n 2 du r i n g summer. Genus Thalassiqnema GRUNOH Grunow(in Van Heurck, Syn., 1881-1885) t r a n s f e r r e d Synedra l i t z s c h i o i d e s i n t o T h a l a s s i q t h r i x with the note: "On p o u r r a i t p eut-etre en c r e e r un nouveau genre nomme T h a l a s s i o n e i a GRUN. ". S i l v a ( i n a f o o t n o t e of Hasle and flendiola*s paper, 1967) pointed out that "H. And M. P e r a f a l l o (Diatomees marines de France, p. 308, 1897-1908) c l e a r l y proposed T^aiassionema as a subgenus of Synedra , and with French d e s c r i p t i o n , based on S.. N i t z s c h i o i d e s GRON; , and the use by M. Peragallo(Deuxieme E x p e d i t i o n A n t a r c t i g u e F r a n c a i s e , p. 69, 1921) of Tha,lassionema as a genus can be considered as an e l e v a t i o n of subgenus to genus rank". However, there has been some arguments c o n c e r n i n g the a u t h o r s h i p of the genus Thalassionema. Hendey(1937, 1964) i n s i s t e d t h a t Grunow's p u b l i c a t i o n of the name Thalassionema must be r u l e d as i n v a l i d and t h a t Hustedt should be c o n s i d e r e d as the author, s i n c e he gave the f i r s t generic " d e s c r i p t i o n , f o l l o w e d by a d e s c r i p t i o n of Tju n i t z s c h i o i d e s ^ . Hasle and Mendiola (1967) a t t r i b u t e d to Grunow the authorship of the genus, but l e a v e to Hustedt the a u t h o r s h i p of new combination 165 Thalassioneffla n i t z s c h i o l d e s (GSUNOW) HOSTEDI . l a m i n agreement. Thalassionema n i t z s c h i o i d e s (GHONOW) HUSTEDT ~P1. 20, f i g 7 6a, b~ Hustedt 1931-59, p. 244, f i g . 725 Hasle & Mendiola 1967, p. 111, f i g s . 5, 11-17, 27-34, 39-44 A very common n e r i t i c s p e c i e s with world-wide d i s t r i b u t i o n . In the study area i t was one of the most common and fre g u e n t s p e c i e s . I t was major p o p u l a t i o n s during summer and u s u a l l y f a i r l y abundant duri n g the other seasons. Genus T h a i a s s i p t h r i x CLEVE & GRUNO» T ^ a l a g s i o t h r i x f r a u e n f e l d i i GRUNOW Pl.~20, f i g . 7a,b~ Hustedt 1931-59, p. 247, f i g . 727 Hasle & Mendiola 1967, p. 113, f i g s . 9, 10, 21, 38, 47-52 Simonsen 1974, p. 37, p l . 24, f i g . 4 A common oc e a n i c temperate s p e c i e s . In the study a r e a t h i s s p e c i e s was common, but not abundant. Genus A s t e r i o n e l l a HASSAL A s t e r i o n e l l a bleakeleyj. H. SMITH P l . 21, f i g . 1 Hustedt 1931-59, p. 253, f i g . 732 A n e r i t i c s p e c i e s . Observed o c c a s i o n a l l y i n the study area, A s t e r i o n e l l a formosa HASSAL P l . 3 , f i g . 1 Hustedt 1 9 3 1 - 5 9 , p. 2 5 1 , f i g . 7 2 9 166 A very common freshwater s p e c i e s with a wide d i s t r i b u t i o n . In the study area t h i s s p e c i e s was r e l a t i v e l y common a t s t a t i o n 2 dur i n g summer. I s t e r i o n e l l a a i a c i a l i s , CASTRACANE P l . 21, f i g . 2a, b Koerner 1970, p. 616 Simonsen 1974, p. 38 Syn.: A s t e r i o n e l l a j a p o n i c a CLEVE Hustedt 1931-597 p.~254, f i g . 743 Cupp 1943, p. 188, f i g . 138 A cosmopolitan n e r i t i c s p e c i e s of t r o p i c a l t o temperate l a t i t u d e s , In the study area t h i s s p e c i e s was common and abundant during summer. A s t e r i o n e l l a k a r i a n a GRONOW ~P1. 24, f i g . 3 Cupp 1943, p. 190, f i g . 139 Hustedt 1931-59, p. 256, f i g . 735 A n e r i t i c , b o r e a l a r c t i c s p e c i e s . Not very common i n the study area. Suborder Monoraphidineae Family Achnanthaceae KUETZING Genus Achnanthes BORY Achnanthes l q n g i p e s AGARDH ~Pl7~21, f i g . 4 Hustedt 1931-59, p. 427, f i g . 878 Hendey 1964, p. 174, p l . 28, f i g s . 1-6; p l . 42, f i g . 2 A cosmopolitan l i t t o r a l s p e c i e s . Not common i n the study area. 167 Achnanthes l a n c e o l a t a (BREB.) GRUNOW Pl7~21, f i g 7 5 Hustedt 1931-59, p. 408, f i g . 863 a-d Cl e v e - E u l e r 1953b, p. 25, f i g . 527 a-c A freshwater l i t t o r a l s p e c i e s . Observed on l y at s t a t i o n 2 i n March. Genus Cocconeis EHRENBERG Cocconeis c l a n d e s t i n a A. SCHMIDT Pl7 21, fig 7 6 Hustedt 1931-59, p. 331, f i g . 748 C l e v e - E u l e r 1953b, p. 4, f i g . 488 A l i t t o r a l s p e c i e s . Observed only at s t a t i o n 5 i n J u l y . Cocconeis c o s t a t a GREGORY ~Hustedt~1931-59, p. 332, f i g . 785 Hendey 1964, p. 179 A l i t t o r a l s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y ccmmon, but never abundant. Cocconeis d e c i p i e n s CLEVE PI. 21, f i g . 9 Hustedt 1931-59, p. 353, f i g . 808 A l i t t o r a l s p e c i e s . Observed only at s t a t i o n 3 i n November. Cocconeis diru.pta GREGORY Pl7~21,~fig. 8 Hustedt 1931-59, p. 354, f i g s . 809 a-c Hustedt 1931-59, p. 354, f i g s . 809 a-c Hendey 1964, p. 177 A l i t t o r a l s p e c i e s . Not common i n the study area, 1 6 8 Cocconeis d i s c u l o i d e s HCSTEDT PI. 2 l 7"*fig. 10 Hustedt 1955, p. 17, p i . 5, f i g s . 8-11; p i . 7, f i g . 8 Hendey 1964, p. 178, f i g s . 21, 22 A l i t t o r a l s p e c i e s . Not common i n the study area. Cocconeis d i s c u l u s (SCHUMANN) CLEVE ~P1.~21, f i g . 11 Hustedt 1931-59, p. 345, f i g . 799 Hendey 1964, p. 178, p i . 28, f i g . 19 A l i t t o r a l s p e c i e s , f r e g u e n t l y found i n brackish-water. Observed only at s t a t i o n 3 i n October i n the study a r e a . Cocconeis ornata GREGORY Pl7~21, f i g . 12 Hustedt 1931-59, p. 339, f i g . 739 A l i t t o r a l s p e c i e s . Observed only at s t a t i o n 4 i n May. Cocconeis p e l l u c i d a GRUNOW PI. 21, f i g . 13 Hustedt 1931-59, p. 357, f i g . 812 A marine s p e c i e s . O c c a s i o n a l l y observed i n the study area. Cocconeis filacentula EHHENBERG var. k l i n o r a g h i s GEITLER ~P1. 2 7 , " f i g . 14 Hustedt 1931-59, p. 348, f i g . 803 A freshwater l i t t o r a l form. Observed only at s t a t i o n 3 i n May. Cocconeis pseudomargjnata GREGORY ~P1. 21, f i g . ~ ? 5 Hustedt 1931-59, p. 359, f i g . 810 169 A l i t t o r a l s p e c i e s . Observed only at s t a t i o n 3 i n June. Cocconeis s c u t e l l u m EHRENBERG P l . 25, f i g . 16 Hustedt 1931-59, p. 337, f i g . 790 A cosmopolitan marine l i t t o r a l s p e c i e s , o f t e n t y c h o p e l a g i c . T h i s s p e c i e s was very common, but not abundant i n the study area. Cocconeis s c u t e l l u m EHRENBERG var. garya GRUNOH PlT 257 f i g . 17 Hustedt 1931-59, p. 33,, f i g . 791 A l i t t o r a l form. In the study area t h i s v a r i e t y was o c c a s i o n a l l y observed, but only at s t a t i o n 3 d u r i n g winter. Genus Rhoicosphenia GRUNOi Rhoicos£henia curyata (KOETZ) GRUNOS P1.~217 f i g 7 18 Hustedt 1931-51, p. 430, f i g . 879 Hendey 1964, p. 183 A very common brackish-water s p e c i e s . Not very common i n the study area. Suborder B i r a p h i d i n e a e Family Naviculaceae KUETZING Genus D i p l q n e i s EHRENBERG Dip_loneis l i n e a t a (DONK.) CLEVE pI7 37 ~ f i g . 2 Hustedt 1931-59, p. 677, f i g . 1069 Hendey 1964, p. 223, p. 32, f i g s . 5, 13 170 A l i t t o r a l s p e c i e s with wide d i s t r i b u t i o n . Observed on l y at s t a t i o n 1 i n June i n the study area. 2i£i2S§is I§tula (A. SM.) CLEVE P l . 2T, f i g . 19 Hustedt 1931-59, p. 678, f i g . 1070 Hendey 1964, p. 224, p l . 32, f i g . 6 A l i t t o r a l s p e c i e s . Rare i n the study area. Genus Mastogloia TH WAT. TES l a s t g g i g i a gvata GRDNOW Pl.~21 , f i g . 20 Hustedt 1931-59, p. 476, f i g . 895 A marine warm water s p e c i e s . Observed only at s t a t i o n 5 i n J u l y . Genus Navicula BORY Navi c u l a cgmfilanatgides HUSTEDT P l . 2l7 f i g . 21 Hustedt 1961-66, p. 340, f i g . 1451 A marine s p e c i e s . In the study area t h i s s p e c i e s was f a i r l y common durin g s p r i n g and summer. Na v i c u l a d i r e c t a (W. SM.) RALFS Pl7 2l7 f i g . 2 2 C l e v e - E u l e r 1953b, p. 129, f i g . 751a Hendey 1964, p. 202 A cosmopolitan b e n t h i c s p e c i e s , but f r e g u e n t l y found i n the plankton. O c c a s i o n a l l y observed i n the study area. 171 Na v i c u l a g i b b u l a CLEVE var. e l l i p t i c a A. CLEVE PI. 21, f i g . 23 C l e v e - E u l e r 1953b, p. 176, f i g s . 68b, c A marine b e n t h i c s p e c i e s . Bare i n the study area. N a v i c u l a g l a c i a l i s (CLEVE) GRIT NOW PI. 2l7 f i g . 24 Hustedt 1931-5 9, p. 648, f i g . 1650 A marine l i t t o r a l s p e c i e s . Bare i n the study area. Navicula hennedyii W. SMITH PI. 21, f i g . 25 Hendey 1964, p. 212, p i . Hustedt 1961-66, p. 453, A common l i t t o r a l s p e c i e s , was observed o n l y at s t a t i o n 4 i n Navicul a l a t i s s i m a GREGORY P l . ~ 2 1 , ~ f i g . 26 Hendey 1964, p. 206, p i . Hustedt 1961-66, p. 715, 33, f i g . 74 f i g s . 1516b, c, e-h; 1518 In the study area t h i s s p e c i e s November. 31, f i g . 17 f i g . 1701 A widely d i s t r i b u t e d l i t t o r a l s p e c i e s . Observed only a t s t a t i o n 3 i n October. N a v i c u l a l y r a EHRENBERG P l.~21, f i g . 27 H e n d e y 1964, p . 209, p i . 33, f i g . 2 H u s t e d t 1961-66, p . 500, f i g . 1549 A common l i t t o r a l s p e c i e s . Observed only a t s t a t i o n 2 i n January. Navic u l a l y r a EHRENBERG 172 forma genudata GRUNOW PI. 22, f i g 7 1 Hustedt 1961-66, p. 506, f i g . 1552 Syn.: N a v i c u l a l y r a EHRENBERG wornardt 1967, p. 82, f i g s . 189, 190, 192 T h i s form was recorded as a f o s s i l diatom of Miocene and P l i o c e n e i n C a l i f o r n i a . In the study area t h i s taxon was observed at s t a t i o n 3 i n January and at s t a t i o n 4 i n Febuary. Navic u l a p a l p e b r a l i s BRIBISSON Pl7 22, f i g . 2 Hendey 1964, p. 216, p i . 34, f i g s . 13-19 A l i t t o r a l s p e c i e s . T h i s s p e c i e s was r e l a t i v e l y common i n the study area. N a v i c u l a rhyncocephala KUETZING Pl.~22, fig7 3 Cl e v e - E u l e r 1953b, p. 157, f i g s . 817 a-g Hendey 1964, p. 199 A common f r e s h water s p e c i e s , o f t e n found i n b r a c k i s h -waters. Not common i n the study area. N a v i c u l a salinarum GRUNOW P l . ~ 2 2 , ~ i g . 4 Cl e v e - E u l e r 1953b, p. 159, f i g . 820a Hendey 1964, p. 199 A cosmopolitan brackish-water benthic s p e c i e s , o f t e n found i n plankton. In the study area t h i s s p e c i e s was o c c a s i o n a l l y observed. N a v i c u l a t e n u i s CLEVE-EULER PI. 22, f i g . 5 173 C l e v e - E u l e r 1953b, 131, f i g , 756f A brackish-water s p e c i e s . O c c a s i o n a l l y observed i n the study area. N a v i c u l a v i r i d u l a KUETZING P l . 2 2 7~fig. 6 Hendey 1951, p. 53, p l . 16, f i g . 5 A freshwater s p e c i e s , o f t e n found i n brackish-water. In the study area t h i s s p e c i e s was observed o n l y a t s t a t i o n 4 i n May. Genus C a l o n e i s CLEVE Ca l o n e i s b r e y i s (GREG.) CLEVE var. vexans (GRUN.) CLEVE P l . 22, f i g . ~ 7 C l e v e - E u l e r 1955, p. 89, f i g s . 1123 b-g A marine and brackish-water form. Rare i n the study area. C a l o n e i s l a t i u s c u l a (KUETZ.) CLEVE Pl.~22, f i g . 8 C l e v e - E u l e r 1955, p. 93, f i g s . 1134a, b A freshwater s p e c i e s . Observed only a t s t a t i o n 2 i n September. Genus Cymbella AGARDH Cymbella asnera A. CLEVE-EULER P l . 22, f i g . 9 C l e v e - E u l e r 1955, p. 166, f i g s , 1256 a-c A f r e s h water s p e c i e s . Observed only at s t a t i o n 2 i n May. 174 Cymbella c i s t u l a HEMPS. PI.""22, f i g . 10 Cl e v e - E u l e r 1955, p. 163, f i g s . 1251 a-c A fresh-water s p e c i e s . Observed at s t a t i o n s 1 , 2 , and 3 i n J u l y . Bare i n the study area. Genus P i n n u l a r i a EHBENBEBG P i n n u l a r i a legujien EHBENBEBG PI. 22, f i g . 11 C l e v e - E u l e r 1955, p. 50, f i g . 1070a A f r e s h water s p e c i e s . Observed only a t s t a t i o n 1 i n May. PlSILUisria t r a n s v e r s a (A. SM.) MAYEB Pl.~22*7~fig. 12 Cl e v e - E u l e r 1955, p. 71, f i g s . 1095a, b A fresh-water s p e c i e s . Observed only at s t a t i o n 1 i n May. Genus Trachyneis CLEVE Trachyneis aspera (EHB.) CLEVE PI. 22, f i g . 13 Hendey 1951, p. 55, p i . 8, f i g . 9 C l e v e - E u l e r 1955, p. 6, f i g . 976f A l i t t o r a l s p e c i e s . Observed on l y at s t a t i o n 1 i n March. Genus F r u s t u l i a H. PEfiAGALLO F r u s t u l i a rhomboides (EHB.) DE TONI PI. 22, f i g . 14 C l e v e - E u l e r 1952, p. 7, f i g . 1326a Hendey 1964, p. 239 A common fresh-water l i t t o r a l s p e c i e s . Observed only at s t a t i o n 1 i n March. 175 Genus T r o p i d o n e i s CLEVE T r o p i d o n e i s a n t a r c t i c a GRUNOW var. E2il£iasta GEAN S ANGST P l . 22, f i g . 15 Gran & Angst 1931, p. 501, f i g . 90 Cupp 1943, p. 197, f i g . 150 A l i t t o r a l or n e r i t i c form. In the study area t h i s v a r i e t y was f a i r l y common except i n summer, but was never abundant. T r o p i d o n e i s l g p i d o p t e r a GREGORY Pl.~227 f i g . 16 Cupp 1943, p. 197, f i g . 149 Cl e v e - E u l e r 1952, p. 28, f i g . 1386 A l i t t o r a l s p e c i e s , o f t e n found i n plankton. Observed only at s t a t i o n 1 i n May. Genus Amphora EHRENBERG Amphora exigua GREGORY ~ P l . 3, f i g . 3 Pe r a g a l l o 1897-1908, p. 730, p l . 50, f i g s . 30, 31 Hendey 1964, p. 261 A l i t t o r a l marine a r c t i c s p e c i e s . O c c a s i o n a l l y observed i n the study area. Amphora g r a e f f i GRUN08 var. • minor PERAGALLO P l . 9, f i g . ~ 4 P e r a g a l l o 1897-1908, p. 211, p l . 46, f i g s . 14, 15 Hendey 1964, p. 263, p l . 37, f i g . 8 A marine s p e c i e s . Observed only a t s t a t i o n 1 i n October. Amphora l i n e o l a t a (EHR.) KUETZING Pl7~227 f i g . 17 176 P e r a g a l l o 1897-1908, p. 225, p i . 50, f i g s . 10-12 Boyer 1927, p. 264 A brackish-water s p e c i e s . Observed only a t s t a t i o n 3 i n May. ii£li2ia E a s i o CLEVE var. parv u l a FLO EG EL PI. 22, f i g . 18 P e r a g a l l o 1897-1908, p. 199, p i . 44, f i g s . 9-10 A marine and brackish-water form. Observed only a t s t a t i o n 4 i n February. Genus Pleurosigma W. SMITH pleurosigma acutum NORMAN PI. 23, f i g . 1 Van Heurck, 1896, p. 254, p i . 35, f i g s . 914, 915 A marine s p e c i e s . Observed only a t s t a t i o n 1 i n January. Pleurosigma an^ulatum {QUERETT) W. SMITH Pl.~23, figT 2 C l e v e - E u l e r 1952, p. 23, f i g . 1372 Hendey 1964, p. 245, p i . 35, f i g s . 1-3; p i . 41, f i g . 6 A brackish-water s p e c i e s . In the study area t h i s s p e c i e s was o f t e n found during winter. Pleurosigma elongaturn W. SMITH PI. 23, f igT 3 Cupp 1943, p. 196, f i g . 147 C l e v e - E u l e r 1952, p. 21, f i g . 1365 A marine and brackish-water l i t t o r a l s p e c i e s , o f t e n found i n plankton. O c c a s i o n a l l y observed i n the study area. 177 Pleurosigma formosum W. SMITH Pl.~23, f i g . 4 Brunei 1962, p. 159, p l . 42, f i g s . 3, 4 Hendey 1964, p. 242 A marine s p e c i e s with a wide d i s t r i b u t i o n . In the study area t h i s s p e c i e s was f a i r l y common. Pleurosigma formosum w. SMITH var. l o n g i s s i m a GEDNOW P l . 23, f i g T 5 Cleve 1894-96, i , p. 45 Valves l a n c e o l a t e , s l i g h t l y sigmoid, t a p e r i n g to the end. Raphe s t r o n g l y developed, s l i g h t l y sigmoid, e c c e n t r i c a t the ends. Valve face s t r i a t e , t r a n s v e r s e s t r i a e f i n e , about 16 i n 10um, o b l i g u e s t r i a e c r o s s i n g each other at angle of approximately 90, about 12 i n 10um. Length of v a l v e 395^111, breadth 53pm. T h i s v a r i e t y i s d i s t i n g u i s h e d from the s p e c i e s by the valve shape, raphe, and s i z e . A marine form. Observed only a t s t a t i o n 1 i n December. pi§U£2sigma longum CLEVE Pl.~23, f i g . 6 C l e v e - E u l e r 1952, p. 21, f i g . 1366 Hendey 1964, p. 243 A marine c o l d water s p e c i e s . In the study area t h i s s p e c i e s was o c c a s i o n a l l y observed during winter. Pleurosigma normanii RALFS P l . 23, f i g . .7 Cupp 1943, p. 196, f i g . 148 178 Hendey 1964, p. 244 One of the commonest and most widely d i s t r i b u t e d of £l§MI°sig.ma s p e c i e s , ft l i t t o r a l form, but or ten found i n plankton. In the study area t h i s s p e c i e s common, but never abundant, Pleurosigma nubecula W. SMITH PI. 2 3 , " f i g . 8 C l e v e - E u l e r 1952, p. 23, f i g s . 1375a,b Hendey (1964) considered t h i s taxon as a synonym of Ri. intermedium which i s u s u a l l y very l a r g e . I p r e f e r t o f o l l o w H. Smith's s e p a r a t i o n of these two ta x a , because I have never had a chance t o compare them. T h i s taxon i s marine, o f t e n found i n plankton, but was observed o n l y at s t a t i o n 4 i n May i n the study area. Genus Gyros icj ma HAS SAL Gyrosigma balticum (EHR.) CLEVE PI. 23, f i g . 9 C l e v e - E u l e r 1952, p. 11, f i g . 1331 Hendey 1964, p. 248, p i . 35, f i g . 9 A common marine and brackish-water l i t t o r a l s p e c i e s . Observed only at s t a t i o n 4 i n November i n the study a r e a . Gyrosigma f a s c i o l a (EHR.) CLEVE "var7 s u l c a t a GRUNOw PI. 23, f i g . ~ 1 0 Hustedt 5 Aleem 1951, p. 188, f i g . 2a Valves l a n c e o l a t e . Ends of valve markedly attenuated , 179 c u r v i n g i n o p p o s i t e d i r e c t i o n s . Apices s l i g h t l y i n f l a t e d . Raphe c e n t r a l , s t r a i g h t i n the v a l v e . Valve face s t r i a t e . Transverse and l o n g i t u d i n a l s t r i a e very f i n e , a b o u t 22 i n 10yum or more. Length o f valve 82^im, breadth 12yum. A marine l i t t o r a l s p e c i e s . Often found i n plankton. Observed only at s t a t i o n 3 i n December. Gyrpsigma•scaleroides RABENHORST var. s c a l p r o i d e s P l . ~ 2 3 7 ~ f i g . 11 Boyer 1916, p. 76, p l . 38, f i g . 9 Valves l i n e a r - l a n c e o l a t e , s l i g h t l y sigmoid, with obtuse ends. Raphe n e a r l y s t r a i g h t . A x i a l area very narrow. C e n t r a l nodule e l l i p t i c a l . Valve face f i n e l y s t r i a t e . Transverse s t r i a e about 22 i n 10yum. L o n g i t u d i n a l s t r i a e a l i t t l e f i n e r . Length of valve 49yum, breadth 8.5yum. A freshwater s p e c i e s . Observed only a t s t a t i o n 5 i n January. Gyrosigma s t r i g i l i s (8. SM.) CLEVE Pl7~23, f i g . 12 C l e v e - E u l e r , 1952, p. 11, f i g . 1333 A b r a c k i s h water s p e c i e s . Observed only a t s t a t i o n 5 i n Junuary. Gyro s i (j ma t e n u i r p s t r i s (GRON.) CLEVE ~P1. 23, f i g . ~ 1 3 C l e v e - E u l e r 1952, p. 13, f i g . 1340 A marine l i t t o r a l s p e c i e s , o f t e n found i n plan k t o n . In the 180 study area t h i s s p e c i e s was o c c a s i o n a l l y observed at s t a t i o n s 1, 2, and 3. Gyrosigma sp. P l . 23, f i g . 14 Valves very narrow, l i n e a r - l a n c e o l a t e , s l i g h t l y sigmoid with sub-acute ends. Raphe c e n t r a l and s t r a i g h t i n the valve except i n end r e g i o n s and there more sigmoid than the v a l v e . A x i a l area very narrow. C e n t r a l nodule s m a l l , broadly e l l i p t i c a l . Valve face s t r i a t e and very f i n e . Transverse s t r i a e about 20 i n 10yum, l o n g i t u d i n a l s t r i a e much f i n e r , s c a r c e l y v i s i b l e . Length of valve 113-136^am, broadth 7-9yam. T h i s new taxon i s very c l o s e to G, tenuissima and d i f f e r e n t from the s p e c i e s i n v a l v e shape and s i z e . I t w i l l be named as Gy.ro s i g n a t e n u i s s i m a var. Ian ceo l a t a . .  T h i s taxon i s probably a marine l i t t o r a l form and was observed a t s t a t i o n 2 during winter i n the study area. Genus Haslea SIMONSEN Simonsen{1974) has r e c e n t l y named t h i s genus, s e p a r a t i n g the Fusiformes group from the genus N a v i c u l a . The Fu s i f o r m e s group was o r i g i n a l l y formed by Cleve(1984). In t h i s grouping v a l v e s of the c e l l are narrow, l i n e a r to l a n c e o l a t e . The raphe i s s t r a i g h t with an i n d i s t i n c t a x i a l and c e n t r a l area. Valve has t r a n s a p i c a l , p a r a l l e l , and s t r a i g h t a p i c a l rows of a r e o l a e on i t s s u r f a c e . T h i s group of the genus Navic u l a was accepted as a 181 section by Hendey(1964) and Hustedt (1961-66). Cleve-Euler(1951-55) included t h i s group i n the section Bntoleiae which includes the Fusiformes group and seme more taxon with more or less radiating s t r i a e . Patrick (1959) ranked t h i s group as a subgenus in Navicula . However, thi s subgenus was considered by Simonsen (1974) to be i n v a l i d because the name of subgenus does not comply with the International Code of Botanical Nomenclature: the subgenus name Fusiformes i s an adjective i n pl u r a l and not a noun. Recent investigations(Helmcke & Kreiger, 1954; Schrader, 1973; Robert, 1973) provide s u f f i c i e n t information to separate the new genus Haslea from Navicula on the basis of the transverse and longitudinal s t r i a e of the valve structure and the structure of central nodule. Simonsen interprets the new genus Haslea as a l i n k between Navicula and SZEosigma^Pleurosigma . I am i n agreement with t h i s . Also I believe that Haslea i s closer to Pleurosigma than to Gyrosigma because the pattern of s t r i a t i o n i n Haslea i s exactly same as in Pleurosigma. Hasle gigantea (HUSTEDT) SIMONSEN Pl .~24, f i g . 1 Simonsen 1974, p. 47, p i . 31, f i g . 1 Syn*: Navicula gigantea HUSTEDT Hustedt 1967-66, p. 40, f i g . 1194 Navicula cf. vitrea SCHRAEDER Schraeder 19737~pT 208, p i . 9, f i g s . 1-5 A marine warm water species with n e r i t i c tendency. Observed only at Station 5 during spring i n the study area. Haslea wawrikae (HUSTEDT) SIMINSEN 182 Simonsen 1974, p. 48 Syn.: Navicula wawrikae HUSTEDT Hustedt 1961-6 6, p. 52, f i g . 1204 A marine warm water s p e c i e s . In the study area i t was o f t e n observed at s t a t i o n s 4 and 5 i n September, but was never abundant. Family Epithemiaceae GRUNOI Genus Epithemia De BREBISSON Epithemia t u r g i d a (EHR.) KUETZING P l . 24, f i g . 3 Boyer 1916, p. 111, f i g . 14 C l e v e - E u l e r 1952, p. 39, f i g . 1410 a-e A brackish-water to f r e s h water s p e c i e s . Not. common i n the study area. Genus Rhopalodia MUELLER Rhopalodia gibba (EHR.) 0. MUELLER var. y e n t r i c o s a (KUETZ) H. PERAGALLO P l . 3, f i g . 5 C l e v e - E u l e r 1952, p. 44, f i g . 1416c, d Hendey 1964, p. 272 A f r e s h water and brackish-water s p e c i e s . Observed only at s t a t i o n 2 i n June. Genus D e n t i c u l a KUETZING D e n t i c u l a seminae SIMONSEN 5 KANAYA P l . 3, f i g . 6 Simonsen S Kanaya 1961, p. 503, p l . 1, f i g s . 26-30 Sy.: D e n t i c u l a marina SEMINA Semina 1956, p. 82 183 Simonsen and Kanaya(1961) changed Semina's name on the ground t h a t i t has already been used f o r another s p e c i e s , Dimerogramma marinum (GREG.) 5ALFS = D.. Marina GEE GOBY . A marine s p e c i e s . In the study area t h i s s p e c i e s was observed at s t a t i o n s 3 and 4 and was moderately abundant at s t a t i o n 3 i n September. Family N i t z s c h i a c e a e GRUNOW Genus Hantzschia GRONOW Hantzschia v i r g a t a (ROPER) GRUNOH var. g r a c i l i s HOSTEDT PI. 24, f i g . 4 Hendey 1964, p. 285, p i . 39, f i g . 13 A marine l i t t o r a l s p e c i e s . In the study area i t was o c c a s i o n a l l y observed at s t a t i o n 4 during s p r i n g . Genus B a c i l l a r i a GMELIN B a c i l l a r i a p a x i l l i f e r (0. MOELLER) HENDEY PI. 24, f i g . 5 Hendey 1951, p. 74; 1964, p i . 274, p i . 21, f i g . 5 Syn.: Baci 1.1 aria, paradoxa GMELIN Hustedt "1930,~p. 396, f i g . 755 Simonsen 1974, p. 49 N i t z s c h i a paradoxa GMELIN GRUNOW Cupp 1943, p. 206, f i g . 159 Cl e v e - E u l e r 1952, p. 69, f i g . 1457 a-d N i t z s c h i a p a x i l l i f e r (0. MUELLER) HEIBERG Boyer 1927, p. 509 Hendey(1951) poi n t e d out the f o l l o w i n g f a c t s : " T h i s s p e c i e s was f i r s t d e s c r i b e d as V i b r i o • p a x i l l i f e r by Mueller i n 1786, and was renamed as B a c i l l a r i a paradoxa by Gmelin i n 1788. Heiberg(1863), r e c o g n i z i n g the a f f i n i t i e s of Gmelin's s p e c i e s 184 with the genus Ni tzs c h i j L t renamed i t N i t z s c h i a B a x i l l i f e r (MUELLER) HBIBERG. ". Then, he c o r r e c t l y combinated i t as B a c i l a r i a p a x i l l i f e r a ccording t o the l e t t e r of I. C. B. N. However, Simonsen(1974) p r e f e r r e d t o B a c i l l a r i a p a r a d o x a x a r g u i n g t h a t the name B± paradoxa has been well-known f o r 150 years, while Bj_ p a x i l l i f e r has not been so f a m i l i a r . I t i s not j u s t i f i e d and Hendey's combination i s fo l l o w e d hare. A cosmopolitan marine and brackish-water s p e c i e s . In the study area i t was o c c a s i o n a l l y observed during f a l l and winter. Genus N i t z s c h i a HASSALL N i t z s c h i a a c t y d r o p h i l a HASLE ~P1. 24, f i g . 6 Hasle 1965a, p. 35, p i . 2, f i g . 10; p i . 15, f i g s . 19-23, p i . 16, f i g s . 3-7 A n e r i t i c s p e c i e s , c o n f i n e d to extreme i n s h o r e waters (Hasle 1965). I t i s f a i r l y s m a l l i n s i z e . I t i s p o s s i b l e f o r the s p e c i e s to be confused with N.. d e l i c a t u l a which i s one of the commonest s p e c i e s i n the' study area. Under the i n v e r t e d microscope Nj. a c t y d r o p h i l a can be d i s t i n g u i s h e d from d e l i c a t u l a because the valve of the l a t t e r i s more l i n e a r i n shape and gr e a t e r i n length (approx. 30-60 yim longer) than the former. In the study area t h i s s p e c i e s i s r e l a t i v e l y common throughout the year except i n s p r i n g and a f a i r l y l a r g a number were observed at s t a t i o n 1 i n February. 185 N i t z s c h i a a n n u l a r i s W. SMITH PlT 2"T f i g . 7 C l e v e - E u l e r 1952, p. 70, f i g . 1461a Hendey 1964, p. 281, p l . 39, f i g . 6 A marine s p e c i e s . Observed o c c a s i o n a l l y i n the study area. N i t z s c h i a d e l i c a t u l a HASLE ~PlT 24*T f i g . 8 Hasle 1965, p. 37, p l . 14, f i g s . 4, 5; p l . 16, f i g s . 8-18 p l . 17, f i g s . 1-16 T h i s s p e c i e s i s very s i m i l a r to N i t z s c h i a d e l i c a t i s s i m a The e p i t h e t d e l i c a t i s s i m a , however, has been r e j e c t e d by Hasle(1965a), s i n c e the c e n t r a l keel as a d i a g n o s t i c c h a r a c t e r and the p o s s i b l e e x i s t e n c e of two s p e c i e s of a s i m i l a r shape i n the l o c a l i t i e s r e p o r t e d by Cleve, r u l e d out the use of the e p i t h e t . Thus, she d e s c r i b e d s e v e r a l new s p e c i e s , N. d e l i c a t u l a being one of them. A widely d i s t r i b u t e d marine s p e c i e s . In the study area t h i s s p e c i e s was one of the commonest and one of the most abundant s p e c i e s , and had maxima during s p r i n g and summer, N i t z s c h i a i n s i g n i s GREGORY var. i n s i g n i s P l . 2 4 , " f i g . 9 C l e v e - E u l e r 1952, p. 68, f i g . 1454 C e l l s i n g i r d l e view r e c t a n g u l a r with rounded c o r n e r s . Valves l i n e a r - l a n c e o l a t e with s l i g h t l y produced, obtuse ends, and not sigmoid. Keel e c c e n t r i c with s h o r t costae, 4 i n 1Cyim. Valve face punctate, s t r i a e about 12 i n 10yum. Length of valve 192-205jum. 186 A marine s p e c i e s . Observed only at s t a t i o n 4 i n J u l y . l i i z s c h i a j j i t e r r u p t e s t r i a t a SIMONSEN P l . 24, f i g . "lO Simonsen 1974, p. 52, p l . 36, f i g s . 1-8; p l . 37, f i g s . 1-7; p l . 38, f i g s . 1-7 Syn.: N i t z s c h i a i n t e r r u p t a HEIDEN Heiden & icolbe ?928,""p. 665, p l . 7, f i g . 150 Kolbe 1955, p. 174, p l . 2, f i g s . 25-27 A new name f o r t h i s taxon has been s u b s t i t u t e d by Simonsen because N.. i n t e r r u p t a i s not a v a i l a b l e . N.. i n t e r r u p t a (REICHELT) HUSTEDT had been d e s c r i b e d as a name of d i f f e r e n t taxon by Hustedt before Heiden. T h i s taxon seems to be c h i e f l y a t r o p i c a l / s u b t r o p i c a l s p e c i e s i n a l l oceans (Simonsen 1974). In the study a r e a i t was observed only at s t a t i o n 3 i n December. N i t z s c h i a l o n g i s s i m a (BREB.) RALFS Pl7~247 f i g . 11 Cupp 1943, p. 200, f i g . 154 Hasle 1964, p. 20, p l . 1, f i g . 2; p l . 5, f i g . 6; p l . 10, f i g s . 5-7 p l . 11, f i g s . 1-4 A cosmopolitan n e r i t i c s p e c i e s . In the study area i t was one of the commonest s p e c i e s throughout the year and was f a i r l y abundant during summer. N i t z s c h i a p anduriformis GREGORY P l . 24, f i g . 12 P e r a g a l l o 1891-1908, p. 268, p l . 70, f i g s . 3-5 A cosmopolitan marine b e n t h i c s p e c i e s , t y c h o p e l a g i c i n the plankton(Simonsen,1974) i n the study area. This s p e c i e s was 187 observed only at s t a t i o n 1 i n June. N i t z s c h i a Eunctata (W. SM.) GRUNOW var. c o a r c t a t a (GRUNOW) HUSTEDT P l . 24, f i g . 13 A. Schmidt, 1974-1959, p l . 330, f i g . 16 Hendey 1964, p. 278 A marine b e n t h i c s p e c i e s . Observed only a t s t a t i o n 4 i n November. N i t z s c h i a pungens GR UNOW ~PlT~24*7~f i g s . 14a,b Hasle 1965a, p. 25, p l . 1, f i g s . 4-5; p l . .5, f i g s . 7-9; p l . 6, f i g . 3; p l . 7, f i g s . 1-8 Syn.: N i t z s c h i a puncjens GRUNOW var. a t l a n t i c a X L E V E Cupp~9437 p. 202, f i g . 156 A n e r i t i c p l a n k t o n i c s p e c i e s with a wide d i s t r i b u t i o n i n a l l temperate oceans. In the study area t h i s s p e c i e s was very common throughout the year, being r e l a t i v e l y abundant i n J u l y . N i t z s c h i a s e r i a t a CLEVE Pl7"~24,~figs. 15a, b Cupp 1943, p. 202, f i g . 155 Hendey 1964, p. 284, p l . 21, f i g 6 Hasle 1965a, p l . 1, f i g . 1; p l . 3, f i g s . 1-7, 10; p l . 4, f i g s . 1, 2; p l . 6, f i g . 2 A n e r i t i c s p e c i e s with wide d i s t r i b u t i o n i n both northern and southern seas. In the study area t h i s s p e c i e s i s very common throughout the year, and moderately abundant during s p r i n g and summer. N i t z s c h i a s o c i a l i s GREGORY Pl7~25, f i g . 1 P e r a g a l l o 1891-1908, p. 280, f i g s . 7, 8 188 C l e v e - E u l e r 1952, p. 63, f i g . 1456a A marine and brackish-water s p e c i e s . In the study area i t was observed o c c a s o i o n a l l y during winter and s p r i n g . N i t z s c h i a v e r m i c u l a r i s (KUETZ.) GBUNOW ~ P l T 25, f igT""2 C l e v e - E u l e r 1952, p. 72, f i g s . 1468a, b A common f r e s h water s p e c i e s . O c c a s i o n a l l y observed at s t a t i o n s 2, 3, and 4 d u r i n g l a t e s p r i n g . Genus C y l i n d r o t h e c a BABENHOBST C y l i n d r o t h e c a c l o s t e r i u m (EHB.) BEIMANN & LEWIN PI. 3, f i g . 7 Reimann S Lewin 1964, p. 288, p i . 125, f i g s . 1-4 p i . 126, f i g . 5 Syn.: N i t z s c h i a c l o s t e r i u m (EHBENB.) W. SMITH Hustedt 1955, p. 48,~pl. 16, f i g s . 16-18 Hasle 1964, p. 16, t e x t f i g s . 1-10; p i . 5, f i g . 1; p i . 7, f i g s . 1-13; p i . 8, f i g s . 1-8; p i . 9, f i g s . 1-9; p i . 10, f i g s . 1-4 T h i s taxon has been t r a n s f e r r e d from the genus N i t z s c h i a to to genus C y l i n d r o t h e c a by Beimann & Lewin because C y l i n d r o t h e c a d i f f e r s from N i t z s c h i a i n t h a t the raphe was t r a v e r s e d by a s e r i e s of f i b u l a e and not r a i s e d above the valve face and the valve i s t r a v e r s e d by more or l e s s t r a n s a p i c a l s i l i c i f i e d t h i c k e n i n g s . T h i s s p e c i e s i s a cosmopolitan b e n t h i c / p l a n k t o n i c form and a l s o present i n b r a c k i s h water. In the study area i t i s one of the commonest s p e c i e s and u s u a l l y moderately abundant, o f t e n showing f a i r l y l a r g e numbers durin g s p r i n g and summer. However, 189 the c e l l counts might be confused with Cv f u s i f o r m i s , because i t i s very d i f f i c u l t to d i s t i n g u i s h these two taxa under the i n v e r t e d microscope. Family S u r i r e l l a c e a e KUETZING Genus S u r i r e l l a TURPIN S u r i r e l l a Intermedia A A CLEVE P l . 25, f i g s . ~ 3 a , b ~ C l e v e - E u l e r 1952, p. 126, f i g . 1572 Syn.: S u r i r e l l a comis A. SCHMIDT A7~Schmidt "1874-1969, p l . 48 f i g s . 3-7; p l . 20, f i g . 3 A marine be n t h i c s p e c i e s . Observed o n l y at s t a t i o n 4 i n March. S u r i r e l l a r o b u s t a EHRENBERG Pl. " ~ 2 5 , ~ f i g . 4 A. Schmidt 1874-1959, p l . 23, f i g . 3 Boyer 1916, p. 124, p l . 36, f i g . 2 A common f r e s h water s p e c i e s . Observed twice, at s t a t i o n s 2 and 3 during winter. Genus Campylodiscus EHRENBERG Camoylodiscus l a t u s SHADBOLT P l . 25, f i g . 5 P e r a g a l l d 1897-1908, p. 246, p l . 57, f i g . 1 A. Schmidt 1874-1959, p l . 18, f i g s . 21-26 A marine b e n t h i c s p e c i e s . Observed only a t s t a t i o n 1 i n A p r i l . Campylodiscus limbatus EREBISSON P l . 25, f i g s . 6a, b 190 A. Schmidt 1874-1959, p i . 17, f i g s . 2, 3 C l e v e - E u l e r 1952, p. 127, f i g . 1577 A marine b e n t h i c s p e c i e s . Observed on l y at s t a t i o n 4 i n November. Campylodiscus t h u r e t t i i EREBISSON ~ P l . ~ 2 5 , ~ f ig7~~7 P e r a g a l l o 1897-1908, p. 247, p i . 57, f i g . 4-9 A marine b e n t h i c s p e c i e s . Observed only a t s t a t i o n 1 i n March. 191 REFERENCES CITED A l l e n , W. E. 1937. Plankton diatoms of the Gulf of C a l i f o r n i a o btained by t h e G. A l l e n Hancock e x p e d i t i o n of 1936. Univ. South. C a l i f . P r e s s , Hancock P a c i f i c Exp., 3: 47-59. A l l e n , w. E. 1939. Summary of r e s u l t s of twenty years of researches on marine phytoplankton. Proc. 6th Pac. S c i . Cong., 3: 577-583. A l l e n , W. 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A s t a t i s t i c a l study of v a r i a t i o n i n the c a t c h of plankton nets. J . Mar. Res., 3: 1-34. Wornardt, W. W. 1967. Miocene and P l i o c e n e marine diatoms from C a l i f o r n i a . Occ. Rap. Acad. S c i . , 63: 1-108. Yentsch, C. S. 1965. D i s t r i b u t i o n of c h l o r o p h y l l and phaeophytin i n the open ocean. Deep-Sea Res., 12: 653-666. Zar, J . H. 1 9 7 4 . , B i o s t a t i s t i c a l A n a l y s i s . P r e n t i c e H a l l , Inc N. J . , 620 pp. A P P E N D I X Information concerning the previous and new records for the western Canadian waters and new taxa. Sources are given by a key as followings: 1 . Bailey and MacKay, 1915 2 Buchanan, 1966 3 Clemens, 1933 A Kitton, 1867 5 , Legare, 1957 6 : Lord, 1866 7 : Stein, 1975 8 : Stockner,and C l i f f , 1975 9 : Wailes, 1933 NR. : new record NT : new taxon Species Source Achnanthes longipes 1 2 3 Achnanthes lanceolata 7 Actinocyclus s u b t i l i s 3 6 Actinoptychus maculatus NR Actinoptychus senarius 1 2 6 Actinoptychus splendens 2 3 9 Amphora exigua 1 Amphora g r a e f f i i var. minor NR Amphora l i n e o l a t a NR Amphora pusio var. parvula 1 Arachnoidiscus ehrenbergii 1 3 4 Aste r i o n e l l a bleakeleyi NR As t e r i o n e l l a g l a c i a l i s 2 3 9 Asteromphalus heptactis 3 9 As t e r i o n e l l a kariana 3 8 9 Aulacodiscus k i t t o n i NR B a c i l l a r i a paradoxa 1 3 Bacteriastrum delicatulum 3 9 Biddulphia antediluvianus 6 Biddulphia a u r i t a 1 2 3 Biddulphia dubia NR Biddulphia l o n g i c r u r i s 2 3 5 Biddulphia l o n g i c r u r i s var. hyalina 2 Biddulphia obtusa 1 2 4 Caloneis brevis var. vexans NR Caloneis l a t i u s c u l a NR Campylodiscus latus NR Campylodiscus limbatus NR Ast e r i o n e l l a formosa 5 7 Biddulphia sp. NT Species Source Campylodiscus t h u r e t t i i 1 3 C e r a t a u l i n a p e l a g i c a 2 3 8 9 Chaetoceros a f f i n i s 2 3 5 9 Chaetoceros a f f i n i s var. w i l l e i 2 Chaetoceros b r e v i s 5 Chaetoceros ceratosporum NR Chaetoceros c i n c t u s 3 6 9 Chaetoceros compressus 2 3 9 Chaetoceros c o n c a v i c o r n i s 2 3 5 9 Chaetoceros c o n s t r i c t u s 2 5 9 Chaetoceros convoltus 2 3 5 9 Chaetoceros danicus 2 3 9 Chaetoceros d e b i l i s 2 3 5 8 9 Chaetoceros de c i p i e n s 1 3 5 8 9 Chaetoceros didymus 1 2 3 5 9 Chaetoceros d i f f i c i l i s NR Chaetoceros i n g o l f i a n u s NR Chaetoceros l a c i n i o s u s 2 3 5 9 Chaetoceros lo r e n z i a n u s 2 3 5 9 Chaetoceros p s e u d o c r i n i t u s 3 9 Chaetoceros radicans 2 3 5 9 Chaetoceros s i m i l i s 2 5 9 Chaetoceros simplex NR Chaetoceros s o c i a l i s 1 3 Chaetoceros diadema 2 3 9 Chaetoceros s u b t i l i s 1 2 3 Chaetoceros t e t r a s t i c h o n NR Chaetoceros v a n h e u r c k i i 3 5 Species Source Cocconeis clandestina NR Cocconeis costata 1 3 Cocconeis decipiens NR Cocconeis dirupta 1 3 6 Cocconeis disculoides NR Cocconeis disculus NR Cocconeis ornata NR Cocconeis placentula var. klinoraphis NR Cocconeis pellucida NR Cocconeis pseudomarginata 1 3 Cocconeis scutellum 1 3 4 Cocconeis scutellum var. parva 1 Corethron criophilum 1 3 8 Coscinodiscus apiculatus var. ambigua NR Coscinodiscus asteromphalus 1 Coscinodiscus c e n t r a l i s var. p a c i f i c a 3 9 Coscinodiscus curvatulus 1 2 3 Coscinodiscus gigas NR Coscinodiscus g r a n i i 2 9 Coscinodiscus k u e t z i n g i i 1 3 Coscinodiscus lineatus 1 2 Coscinodiscus marginato-lineatus NR Coscinodiscus marginatus 3 9 Coscinodiscus normanii NR Coscinodiscus obscurus NR Coscinodiscus o c u l u s - i r i d i s 1 2 6 Coscinodiscus perforatus 3 Coscinodiscus radiatus 1 2 3 Coscinodis cus r o t h i i 1 3 Coscinodiscus s t e l l a r i s 1 3 9 9 217 Species Source Coscinodiscus w a i l e s i i 2 3 9 C y c l o t e l l a comta NR C y c l o t e l l a s t r i a t a 1 3 C y l i n d r o t h e c a c l o s t e r i u m 2 3 8 Cymbella aspera 7 Cymbella c i s t u l a 7 Dentcula seminae NR D i p l o n e i s l i n e a t a NR D i p l o n e i s v e t u l a NR Ditylum b r i g h t w e l l i i 1 2 3 Epithemia sorex 7 Eucampia zodiacus 1 2 3 F r a g i l a r i a capucina 1 7 9 F r a g i l a r i a c r o t o n e n s i s 2 5 8 F r a g i l a r i a i s l a n d i c a 1 3 F r a g i l a r i a s t r i a t u l a 1 3 4 F r u s t u l i a rhomboides 2 7 Grammatophora angulosa 1 3 Grammatophora marina 1 2 3 Grammatophora maxima 3 Guinardia f l a c c i d a NR Gyrosigma b a l t i c u m NR Gyrosigma f a s c i o l a var. arcuatum NR Gyrosigma s c a l p r o i d e s v ar. s c a l p r o i d e s NT Gyrosigma s t r i g i l i s NR Gyrosigma t e n u i r o s t r i s NR Gyrosigma sp. NT Hantzschia v i r g a t a var. g r a c i l i s NR Haslea gigantea NR Haslea wawrikai NR Species Source Hemiaulus sinensis NR Hyalodiscus s u b t i l i s 1 3 4 6 9 Isthmia nervosa 3 4 6 9 Leptocylindrus danicus 2 3 5 8 9 Leptocylindrus mediterraneus NR Licmophora abbreviata 3 Licmophora ehrenbergil 4 Licmophora paradoxa 1 3 Licmophora f l a b e l l a t a 3 Lithodesmium undulatum 3 Mastogloia ovata NR Melosira granulata var. angustissima NR Melosira i s l a n d i c a subsp. helvetica 7 Melosira i t a l i c a NR Melosira i t a l i c a subsp. subarctica NR Melosira moniliformis 2 3 5 8 Melosira nummuloides 2 3 4 9 Melosira s o l 3 Melosira varians 1 7 Navicula complanatoides NR Navicula di r e c t a ]_ 3 Navicula gibbula var. e l l i p t i c a NR Navicula g l a c i a l i s NR Navicula hennedyi 3 Navicula latissima NR Navicula l y r a 1 3 Navicula l y r a f. denutata NR Navicula palpebralis 3 Navicula rhyncocephala 2 Navicula salinarum 1 Navicula tenuis NR 219 Species Source Navicula v i r i d u l a 1 Nitzschia actydrophila NR Nitzschia angularis 1 3 Nitzschia d e l i c a t u l a NR Nitzsc h i a longissima 1 2 3 9 Nitzschia i n s i g n i s var. i n s i g n i s NT Nitzschia i n t e r u p t e s t r i a t a NR Nitzschia panduriformis 3 Nitzschia panduriformis var. minor NR Nitzschia pungens 2 Nitzschia seriata 1 3 8 9 Nitzsc h i a s o c i a l i s 1 Nitzschia vermicularis 7 P a r a l i a sulcata 2 3 5 9 Pinnularia legumen 7 Pinnularia transversa NR Plagiogramma vanheurckii NR Plank t o n i e l l a s o l 3 8 9 Pleurosigma angulatum 1 3 Pleurosigma delicatulum 1 Pleurosigma elongatum 2 8 9 Pleurosigma formosum 3 Pleurosigma formosum var. longissima NR Pleurosigma longum NR Pleurosigma normanii 2 Pleurosigma nubecula NR Rhaphoneis amphiceros NR Rhaphoneis s u r i r e l l a NR Rhabdonema adriaticum 3 Rhabdonema arcuatum 1 2 3 Rhizosolenia alata 3 9 Species Source R h i z o s o l e n i a a l a t a f. c u r v i r o s t r i s NR R h i z o s o l e n i a c a l c a r - a v i s NR R h i z o s o l e n i a d e l i c a t u l a 2 3 5 R h i z o s o l e n i a f r a g i l i s s i m a 2 3 R h i z o s o l e n i a hebetata var. semispina 3 5 9 R h i z o s o l e n i a s e t i g e r a 1 2 3 8 Rhoicosphenia curvata 1 3 4 Rhopalodia gibba var. v e n t r i c o s a 7 S c h r o e d e r e l l a d e l i c a t u l a 2 Skeletonema costatum 1 2 3 5 Stephanopyxis n i p p o n i c a 2 3 5 9 S t r i a t e l l a d e l i c a t u l a NR S u r r i r e l l a intermedia NR S u r r i r e l l a robusta 7 Synedra acus 1 Synedra i s a b e l a e var. i s a b e l a e NT Synedra k e r g u e l e n s i s NR Synedra ulna 1 3 4 7 Synedra ulna var. amphirhynchus NR T a b e l l a r i a f e n e s t r a t a 2 7 T a b e l l a r i a f e n e s t r a t a var. a s t e r i o n e l l o i d e s N R T a b e l l a r i a f e n e s t r a t a var. intermedia NR Thalassionema n i t z s c h i o i d e s . 1 2 3 5 T h a l a s s i o s i r a a e s t i v a l i s 3 8 T h a l a s s i o s i r a a n g s t i i 3 T h a l a s s i o s i r a d e c i p i e n s 1 2 3 5 T h a l a s s i o s i r a e c c e n t r i c u s 1 2 3 4 T h a l a s s i o s i r a n o r d e n s k i o e l d i i 2 5 8 9 T h a l a s s i o s i r a p a c i f i c a 2 3 8 9 T h a l a s s i o s i r a polychorda 2 9 221 Species Source T h a l a s s i o s i r a r o t u l a 2 3 9 T h a l a s s i o s i r a sp. A. NT T h a l a s s i o s i r a sp. B. NT T h a l a s s i o t h r i x f r a u e n f e l d i i 1 2 5 Trachyneis aspera 1 3 Trigonium arctium NR Trigonium sp. NT Tropidoneis a n t a r c t i c a var. p o l y p l a s t a 2 3 9 Tropidoneis l e p i d o p t e r a 3 222 PLATE I 1. M e l o s i r a i s l a n d i c a 0. MUELLER subsp. h e l v e t i c a 0. MUELLER 2. R h i z o s o l e n i a c a l c a r - a v i s M. SCHULTZ 3. Chaetoceros b r e v i s SCHUETT 4. Chaetoceros d i f f i c i l i s CLEVE 5. Cheatoceros simplex OSTENFELD 6. Cheatoceros s u b t i l i s CLEVE 7. Hemiaulus s i n e n s i s GREVILLE 222a PLATE I 6 223 PLATE I I 1. Chaetoceros t e t r a s t i c h o n CLEVE 2. Eucampia zodiacus EHBENBEBG 3. S t r i a t e l l a d e l i c a t u l a (KUETZING) GRUNOW 4. T a b e l l a r i a f e n e s t r a t a (LYNGB.) KUETZING 5. Plagiogramma v a n h e u r c k i i GRUNOW PLATE II 223a 224 PLATE I I I 1. A s t e r i o n e l l a formosa HASSAL 2. D i p l o n e i s l i n e a t a (DONK.) CLEVE 3. Amphora exigua GREGORY 4. Amphora g r a e f f i GRUNOW var. minor PERAGALLO 5. Rhopalodia gibba (EHR.) 0. MUELLER var. v e n t r i c o s a H. PERAGALLO 6. D e n t i c u l a seminae SIMONSEN & KSNAYA 7. C y l l n d r o t h e c a c l o s t e r i u m (EHR.) REIMANN & PATRICK PLATE III 224a 6 225 PLATE IV 1. Stephanopyxis n i p p o n i c a GRAN & YENDO (SEM, x640) 2. Hya l o d i s c u s s u b t i l i s BAILEY (x580) 3. P a r a l i a s u l c a t a (EHR.) CLEVE a. Valve view (SEM, x5800), b. G i r d l e view (SEH, x2280) ii. M e l o s i r a g r a n u l a t a (GRUN.) 0. MUELLER var. angustissima 0.MUELLER (xlOOO) 5. M e l o s i r a i t a l i c a (EHR.) KUETZING (xlOOO) 6. M e l o s i r a i t a l i c a (EHR.) KUETZING subsp. s u b a r c t i c a O.MUELLER <x1000) 7. M e l o s i r a m o n i l i f o r m i s (0. MUELLER) AGARDH (x640) 8. M e l o s i r a nummuloides (DILLM.) AGARDH (x670) 9. M e l o s i r a v a r i a n s AGARDH (x420) PLATE IV 225a 226 PLATE V 1. M e l o s i r a s o l (EHR.) KUETZING a. Valve viewfSEM, x1200), b. G i r d l e view (SEM, x1260) 2. S c h r o e d e r e l l a d e l i c a t u l a (PEEAG.) PAVILLARD a. Valve view(SEM, x2300), b. G i r d l e view(x520) 3. L e p t o c y l i n d r u s danicus CLEVE (x330) 4. L e p t o c y l i n d r u s mediterraneus (H.PERAGALLO) HASLE (X450) 5. Corethron c r i o p h i l u m CASTRACANE a. G i r d l e view(x185), b. Valve view(SEM, x2630) PLATE V 226a 227 PLATE VI 1. T h a l a s s i o s i r a a e s t i v a l i s GRAN (SEM, x1300) 2. T h a l a s s i o s i r a a n g s t i i (GRAN) MAKAROVA a. Valve view(SEM, x1230), b. Occluded processes (x6500) 3. T h a l a s s i o s i r a d e c i p i e n s (GRUN.) JOERGENSEN a. Valve view(SEM, x2580) , b. V a l v e / g i r d l e view(SSM, x2640) 4. T h a l a s s i o s i r a e l s a y e d i i FRYXELL (SEM, x2430) PLATE VI 227a 228 PLATE VII 1. T h a l a s s i o s i r a e c c e n t r i c u s (EHR.) CLEVE a. Valve view (SEM, x1195), b. Oblique view(SEM, x1140) 2. T h a l a s s i o s i r a n o r d e n s k i o e l d i i CLEVE a. V a l v e / g i r d l e view(SEM, x2380) , b. Colony(SEM, x1330) 3. T h a l a s s i o s i r a p a c i f i c a GRAN a. Valve view(SEM, x2240), b. Colony(SEM, x520) 228a PLATE VII 229 PLATE VIII 1. T h a l a s s i o s i r a polychorda (GRAN) MAKAROVA a. Valve view (SEM, x2640) , b. G i r d l e view(SEM, x2500) c, S p i n u l a e , l a b i a t e process and s t r u t t e d processes(SEM, X12500) 2. T h a l a s s i o s i r a sp. A. (new). A. Valve view(SEM, x 2 1 5 0 ) , b. X6600 230 PLATE IX 1. T h a l a s s i o s i r a r o t u l a MEUNIEH a. Valve view(SEM, x2400) , b. Colony(SEM, x1275) c. Colony i n wet mount (x460) , d. C e n t r a l s t r u t t e d processes(SEM, x6000) 2. T h a l a s s i o s i r a sp. B (new) a. Valve view (SEM, x1450) , b. L a b i a t e / s t r u t t e d processes (SEM, x2775) c. Colony (SEM, x1300) 230a PLATE IX 231 PLATE X 1. P l a n k t o n i e l l a s o l (WALLTCH) SCHOETT (x495) 2. C y c l o t e l l a comta (EHR.) KUETZING (x335) 3. C y c l o t e l l a s t r i a t u l a (KUETZ.) GRUNOW (x775) 4. Skeletonema costatum (GRVEV.) CLEVE a. G i r d l e view (SEM, x6000), b. Valve view, i n s i d e ( S E M , X5350) 5. C o s c i n o d i s c u s a p i c u l a t u s EHR. var. ambigua GRUNOW (x725) PLATE X 231a 232 PLATE XI 1. C o s c i n o d i s c u s asteromphalus EHBENBEBG (x615) 2. C o s c i n o d i s c u s c e n t r a l e s EHBENBEBG var. p a c i f i c a GRAN S ANGST (SEM, x620) 3. C o s c i n o d i s c u s c u r v a t u l u s GBONOw (x968) H. C o s c i n o d i s c u s g r a n i i GODGH a. Valve view(x450), b. G i r d l e view(x260) 5. C o s c i n o d i s c u s g i g a s EHBENBEBG (x280) 6. C o s c i n o d i s c u s k u e t z i n g i i A. SCHMIDT (x947) 7. C o s c i n o d i s c u s m a r g i n a t o - l i n e a t u s A. SCHMIDT (x1000) 8. C o s c i n o d i s c u s raarginatus EHBENBEBG (x295) 232a PLATE XI PLATE XII C o s c i n o d i s c u s normanii GREGORY (SEM, x1230) Co s c i n o d i s c u s obscurus A. SCHMIDT (x560) C o s c i n o d i s c u s o c u l u s - i r i d i s EHRENBERG (x930) C o s c i n o d i s c u s p e r f o x a t u s EHRENBERG (x665) C o s c i n o d i s c u s r a d i a t u s EHRENBERG (SEM, x1140) C o s c i n o d i s c u s r o t h i i (EHR.) GRUNOW (x665) C o s c i n o d i s c u s w a i l e s i i GRAN 5 ANST (x355) 233a PLATE XII 234 PLATE XIII 1. C o s c i n o d i s c u s s t e l l a r i s ROPES a. Valve view(x245), b. Oblique view (SEM, x990) 2. Actinoptychus maculatus GROVE (x445) 3. Actinoptychus s e r a n i u s EHRENBERG (SEM, x1280) 4. Actinoptychus splendens (SHADB.) RALFS (SEM, x600) 5. A r a c h n o i d i s c u s e h r e n b e r q i i BAILEY (x415) 6. A u l a c o d i s c u s k i t t o n i i ABNOTT (x425) 7. Asteromphalus h e p t a c t i s (BREB.) RALFS (x500) 8. A c t i n o c y c l u s s u b t i l i s (GREG.) RALFS (x625) 234a PLATE XIII 235 PLATE XIV 1. R h i z o s o l e n i a a l a t a ERIGHTWELI (x375) 2. R h i z o s o l e n i a a l a t a BRIGHT, form, c u r v i r o s t r i s GRAN (x500) 3. R h i z o s o l e n i a d e l i c a t u l a CLEVE (x680) 4. R h i z o s o l e n i a f r a g i l i s s i m a BERGON (x490) 5. R h i z o s o l e n i a hebetata (BAIL.) GRAN form, semispina (HENSEN)GRAN (x420) 6. R h i z o s o l e n i a s e t i g e r a BRIGHTWELL (x450) 7. Ditylum b r i g h t w e l l i i (WEST.) GRUNOW (x415) 8. G u i n a r d i a f l a c c i d a (CASTR.) H. PERAGALLO a. G i r d l e view(SEH, x5950) # b. V a l v e / g i r d l e view(SEM, x2200) 9. Lithodesmium undulatum EHRENBERG (x5G0) 10. Chaetoceros a f f i n i s LAUDER (x320) 235a PLATE XIV 236 PLATE XV 1. Chaetoceros a f f i n i s LAUDER var. w i l l e i (GRAN) HUSTEDT (x195) 2. Chaetoceros c i n c t u s GRAN (SEM, x1200) 3. Chaetoceros compresses LAUDER (SEM, x1290) 4. Chaetoceros c o n c a v i c o r n i s MANGIN (x800) 5. Chaetoceros c o n s t r i c t u s GRAN (x450) 6. Chaetoceros c o n v o l t u s CASTRACANE (x465) 7. Chaetoceros danicus CLEVE (x46 5) 8. Chaetoceros d e b i l i s CLEVE(SEM, x1080) 237 PLATE XVI 1. Chaetoceros c e r a t o s p o r u s OSTENFELD (x470) 2. Chaetoceros d e c i p i e n s CLEVE (SEM, x570) 3. Chaetoceros didymus EHRENBERG (x380) 4. Chaetoceros i n g o l f i a n u s OSTENFELD (x175) 5. Chaetoceros l a c i n i o s u s SCHETT (x150) 6. Chaetoceros l o r e n z i a n u s GRDNOW (x395) 7. Chaetoceros p s e u d o c r i n i t u s OSTENFELD (x147) 8. Chaetoceros r a d i c a n s SCHUETT (SEM, x1070) 9. Chaetoceros s i m i l i s CLEVE(SEM, x1225) PLATE XVI 238 PLATE XVII 1. Chaetoceros s o c i a l i s LAUDER <x355) 2. Chaetoceros diadema (GHUN.) HUSTEDT (x390) 3. Chaetoceros v a n h e u r c k i i GRAN (x850) 4. B a c t e r i a s t r u m d e l i c a t u l u m CLEVE (x385) 5. C e r a t a u l i n a b e r g o n i i H. PERAGALLO (x540) 6. B i d d u l p h i a antediluvianum (EHR.) VAN HEORCK (x465) 7. B i d d u l p h i a a u r i t a (LYNGB.) BREBISSON & GODEY (x850) 8. B i d d u l p h i a dubia (BRIGHT.) CLEVE (x660) 9. B i d d u l p h i a l o n g i c r u r i s GREVILLE (x680) 10. B i d d u l p h i a l o n g i c r u r i s GREVILLE var. h y a l i n e (SCHROEDER) CUPP (x385) 238a PLATE XVII 239 PLATE XVIII 1. B i d d u l p h i a obtusa (KOETZ.) SALES <x530) 2. B i d d u l p h i a sp. A. (new) a. (SEM, x1330), b. (SEM, x6800) 3. Trigonium a r c t i c u m (ERIGHT.) CLEVE(SEM, x615) 4. Trigonium sp. (new) a. Valve i n s i d e ( S E M , x1210), b. S t r u t t e d processes(SEM, x2430) 239a PLATE XVIII 240 PLATE XIX 1. Isthmia nervosa KUETZING (x280) 2. Bhabdonema a d r i a t i c u m KUETZING (x445) 3. Bhabdonema arcuatum (LYNGB.) KUETZING (x595) 4. Grammatophora angulosa EHRENBERG (x535) 5. Grammatophora marina (LYNGB.) KUETZING (x385) 6. Grammatophora maxima GRUNOW (x560) 7. Licmophora a b b r e v i a t e AGARDH (x930) 8. Licmophora e h r e n b e r g i i (KUETZ.) GRUNOW (x3 95) 9. Licmophora paradoxa (LYNGB.) AGARDH (x300) 10. T a b e l l a r i a f e n e s t r a t a (LYNGB.) KUETZING var. a s t e r i o n e l l o i d e s GRUNOW (x395) 11. T a b e l l a r i a f e n e s t r a t a var. interm e d i a GRUNOW (x490) 12. Rhaphoneis amphiceros EHRENBERG (x880) 13. Rhaphoneis s u r i r e l l a (EHR.) GRUNOW (x1800) 14. F r a g i l a r i a capucina DESMAZIERE (x430) 15. F r a g i l a r i a c r o t o n e n s i s KITTON (x400) 16. F r a g i l a r i a i s l a n d i c a GRUNOW (x400) 17. F r a g i l a r i a s t r i a t u l a LYNGBYE (x500) PLATE XIX 240a 241 PLATE XX 1. Synedra acus KUETZING (x420) 2. Synedra i s a b e l a e PATRICK var. i s a b e l a (x500) 3. Synedra k e r g u e l e n s i s HEIDEN S KGLBE (x1340) 4. Synedra ulna (NITZ.) EHRENBERG a. Valve view (x400) , b. G i r d l e view(x400) 5. Synedra ulna var. amphirhynchus (EHR.) GRUNOW (x390) 6. Thalassionema n i t z s c h i c i d e s HUSTEDT a. (x445) , b. (SEM, X11900) 7. T h a l a s s i o t h r i x f r a u e n f e l d i i GRUNOW a. (x380) , b. (SEM, x12200) 242 PLATE XXI 1. A s t e r i o n e l l a b l e a k e l e y i . SMITH (x405) 2. A s t e r i o n e l l a g l a c i a l i s CLEVE a. (x130) , b. (x102Q) 3. A s t e r i o n e l l a k a r i a n a GRUNOW (x445) 4. Achnanthes l o n g i p e s AGARDH (x410) 5. Achnanthes l a n c e o l a t a (BREB.) GRUNOW (x865) 6. Cocconeis c a l e n d e s t i n a A. SHCMIDT (xlOOO) 7. Cocconeis c o s t a t a GREGORY (x450) 8. Cocconeis d e c i p i e n s CLEVE (x400) 9. Cocconeis d i r u p t a GREGORY (x470) 10. Cocconeis d i s c u l o i d e s HUSTEDT (x1000) 11. Cocconeis d i s c u l u s (SCHUMANN) CLEVE (x1000) 12. Cocconeis ornata GREGORY (x410) 13. Cocconeis p e l l u c i d a GRUNOW (x575) 14. Cocconeis p l a c e n t u l a HERNBERG var. • k l i n o r a p h i s GEITLER (x640) 15. Cocconeis pseudomarginatus GREGORY (x390) 16. Coccneis s c u t e l l u m EHRENBERG (x885) 17. Cocconeis s c u t e l l u m var. parva GRUNOW (x470) 18. Rhoicosphenia c u r v a t a (KUETZ.) GRUNOW (x545) 19. B i p l o n e i s v e t u l a (A. SCHUMIDT) CLEVE (x545) 20. Mastogloia ovata GRUNOW (x1590) 243 21. N a v i c u l a complanatoides HUSTEDT (x610) 22. N a v i c u l a d i r e c t a (w. SM.) BALES (x460) 23. N a v i c u l a gubbula CLEVE var. e l l i p t i c a A. CLEVE (x850) 24. Navic u l a g l a c i a l i s (CLEVE) GRUNOW (x380) 25. N a v i c u l a hennedyi W. SMITH (x580) 26. N a v i c u l a l a t i s s i m a GREGORY (x800) 27. N a v i c u l a l y r a EHRENBERG (x465) 244 PLATE XXII 1. N a v i c u l a l y r a EHHENBERG form. denudata GRUNOW (x590) 2. N a v i c u l a p a l p e b r a l i s BREBISSON (x830) 3. Navic u l a rhyncocephala KUETZING (x1000) 4. N a v i c u l a salinarum GRUNOW (x490) 5. N a v i c u l a t e n u i s A. CLEVE (x380) 6 . N a v i c u l a v i r i d u l a KUETZING (x540) 7. C a l o n e i s b r e v i s (GREG.) CLEVE var. vexans (GRUN.) CLEVE (x730) 8. C a l o n e i s l a t i u s c u l a (KUETZ.) CLEVE (x1000) 9. Cymbella aspera A. CLEVE(SEM, x595) 10. Cymbella c i s t u l a HEMPR. (x390) 11. P i n n u l a r i a legumen EHRENBERG (x610) 12. P i n n u l a r i a t r a n s v e r s a (A. SCHMIDT) MAYER (x575) 13. Trachyneis aspera (EHR.) CLEVE (x410) 14. E r u s t u l i a rhomboides (EHR.) DETONI (x470) 15. T r o p i d o n e i s a n t a r c t i c a GRUNOW var. p o l y p l a s t a GRAN S ANST (x1280) 16. T r o p i d o n e i s l e p i d o p t e r a GREGORY (x500) 17. Amphora l a n c e o l a t a (EHR.) KUETZING (x550) 18. Amphora pusio CLEVE var. parvula FLOEGEL (x680) 244a PLATE XXII 245 PLATE XXIII 1. Pleurosigma acutum NORMAN (x395) 2. Pleurosigma angulatum (QUEKETT) I. SMITH (x490) 3. Pleurosigma elongatum w. SMITH (x400) 4. Pleurosigma formosum 9, SMITH (x500) 5. Pleurosigma formosum ». SMITH var. l o n g i s s i m a GRUNOW (x380) 6. Pleurosigma longum CLEVE (x405) 7. Pleurosigma normanii RALFS (x500) 8. Pleurosigma nubecula W. SMITH (x590) 9. Gyrosigma b a l t i c u m {EHR.) CLEVE (x500) 10. Gyrosigma f a s c i o l a (EHR.) CLEVE var. s u l c a t a GRUNOW (x1000) 11. Gyrosigma s c a l p r i o d e s RABENHOBST var. s c a l p r i o d e s (x1225) 12. Gyrosigma s t r i g i l i s (W.SM.) CLEVE (x545) 13. Gyrosigma t e n u i r o s t r i s (GRDN.) CLEVE (x575) 14. Gyrosigma sp. (x1135) 245a PLATE XXIII PLATE XXIV 1. Haslea gigantea (HUSTEDT) SIMONSEN (x400) 2. Haslea wawrikae (HUSTEDT) SIMONSEN (x455) 3. Epithemia t u r g i d a (EHR.) KUETZING (x390) 4. Hantzschia v i r g a t a (ROPER) GRUNOW var. g r a c i l i s HUSTEDT (x1225) 5. B a c i l l a r i a p a x i l l i f e r (0.MUELLER) HENDEY (x395) 6. N i t z s c h i a a c t y d r o p h i l a HASLE (x350) 7. N i t z s c h i a a n g u l a r i s W. SMITH (x500) 8. N i t z s c h i a d e l i c a t u l a HASLE (x480) 9. N i t z s c h i a i n s i g n i s GREGORY var. i n s i g n i s (x480) 10. N i t z s c h i a i n t e r r u p t e s t r i a t a SIMONSEN (x480) 11. N i t z s c h i a l o n g i s s i m a (BERB.) RALFS (x455) 12. N i t z s c h i a p a nduriformis GREGORY (x630) 13. N a v i c u l a punctata (W.SM.) var. c o a r c t a t a (GRUNOW) HUSTEDT (x775) 14. N i t z s c h i a pungens GRUNOW a. (SEM, x1180), b. (SEM, x5850) 15. N i t z s c h i a s e r i a t a CLEVE a. (SEM, x1190), b. (SEM, x5900) 247 PLATE XXV 1. N i t z s c h i a s o c i a l i s G'BEGO.fiI (SEM, x1100) 2. N i t z s c h i a v e r m i c u l a r i s (KUETZ.) GBUNOW (x400) 3. S u r i r e l l a i n t e r m e d i a A. CLEVE a. Valve view (SEM, x1200) , b.(SEM,x1220) 4. S u r i r e l l a robusta HEBENBEBG (x510) 5. Campylodiscus l a t u s SHABBOLT (x600) 6. Campylodiscus limbatus BBEBISSCN a. Valve view(x480), b. G i r d l e view (x485) 7. Campylodiscus t h u r e t t i i BBEBISSON (SEM, x1140) 247a PLATE XXV PUBLICATIONS Chung, Y. H. and J. H. Shim. 1970. A study on the brackish water- type of Han River Estuary with special referrence to phytoplankton. Kor. J. Bot., 12(3) : 127-134. Chung, Y. H., J. H. Shim, and M. J. Lee. 1969. Studies on the water pol l u t i o n and productivity i n Kyonggi Bay. I. Phytoplankton. Report for IBP, Kor. Nat. Commit. IBP, No. 3, 16p. Lee, M. J . , S. W. Hong, K. B. Uhm, Y. C. Hah, and J. H. Shim. 1968. A study of marine algae with special reference to a l g i n i c acid. Rep. Ministry S c i . Tech., E67-G15R-21, 32p. Lee, M. J . , J. H. Shim, and C. K. Kim. 1967. On .the marine conditions and Phytoplankton of Yellow Sea i n Summer. Rep. Inst. Mar.. B i o l . S.N.U., 1(6): 1-14. Chung, Y. H. and J; H. Shim. 1965. The phytoplankton and the effects of marine waters i n the lower course of Han River. Kor. J. Bot., 8(4): 47-69. 

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