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A study of oxygen consumption in Colanus plumchrus Marukawa 1921 and implications on vertical migration Topping, Milton Stanlee 1966

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A STUDY OF OXYGEN OOHSUMPTIOH I H Oalanas p l a m e h r a B MAEUZAWA  1921  AND IMPLICATIONS OK VERTICAL MIGHATION  MILTON STANLEE TOPPING B.A., U n i v e r s i t y o f Kansas, 1962 A T h e s i s submitted i n P a r t i a l F u l f i l m e n t o f the Requirements f o r t h e Degree o f Master o f S c i e n c e i n t h e Department of Zoology We accept t h i s t h e s i s as conforming t o t h e required, s t a n d a r d  The U n i v e r s i t y o f B r i t i s h A p r i l , 1966  Columbia  In presenting  this thesis in p a r t i a l fulfilment of  the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make i t freely available for reference  and study.  I further agree that per-  mission for extensive copying of this thesis for scholarly purposes may  be granted by the Head of my Department or by  his representativeso  It i s understood that copying or publi-  cation of this thesis for f i n a n c i a l gain shall not be allowed without my written permission.  Department of  ~/cZ  6±  The University of B r i t i s h Columbia,. Vancouver 8, Canada. Date Q.&  ADAJJ  I q&G,  ii Abstract Oxygen consumption of the eopepodid Y stages o f Oalanas plumohras was studied with respect to environmental and endogenous factors using standard closed chamber technique and Warburg respirometry.  Specimens were collected from San Juan  Channel, Washington and Indian Arm, B r i t i s h Columbia. Rate of oxygen consumption of C, plumchrus (1) i s s i g n i f i c a n t l y decreased by population densities of 5 or more copepods / ml, (2) demonstrates no regular endogenous change, (3) i s not s i g n i f i c a n t l y affected by presence or absence of l i g h t , (4) i s d i r e c t l y proportional to temperature (being v a r i o u s l y l i n e a r and non-linear i n response) throughout the range of 5^20° 0,  (5) does not vary s i g n i f i c a n t l y over a  s a l i n i t y range of 20-35 ppt (but during May 1965 increased at 10 ppt and deoreased at 45 p p t ) , (6) decreases to a minimum below an ambient oxygen concentration of 3 co 0% per l i t e r and (7) i s not s i g n i f i c a n t l y affected by increased hydrostatic pressure corresponding t o a depth of about 400 m,  Response to  a range of temperatures, i n p a r t i c u l a r , indicates that oxygen measurements taken from different c o l l e c t i o n s are s t a t i s t i c a l l y d i f f e r e n t and therefore not d i r e c t l y comparable. In general, the data presented are consistent with McLaren's theory of energy u t i l i z a t i o n and v e r t i c a l migration, although temperature does not always appear to be the most significant factor.  Interaction and v a r i a t i o n o f environmental  factors may explain some of the complexity of v e r t i c a l migration.  iii T a b l e o f Contents page  Abstract  •  • ••• i i  L i s t o f Tables  iv v  L i s t of Figures Acknowledgments • I. II,  I H .  Introduction  VI. VII.  1 3  A. B. C. D. E. P. Gr.  6 6 7 7 7 7 8  Crowding Bhythmicity Light Temperature Salinity • Oxygen c o n c e n t r a t i o n • P r e s s u r e ••  Besults  • •  ..10  Crowding Bhythmicity Light Temperature Salinity Oxygen c o n c e n t r a t i o n Pressure •  10 10 13 13 16 • 18 20  Disoassion A. B. C.  V*  •  M a t e r i a l s and Methods  A* B. C. D. E. F. 0. IV.  vi  C o n s i d e r a t i o n s o f technique Effect of factors Oxygen u t i l i z a t i o n i n nature  Summary......  22 •••• 22~ 24 32 • 37  Literature Cited  39  Appendioes  43  Appendix Appendix Appendix Appendix Appendix Appendix Appendix  43 44 46 47 48 49 50  I . Crowding • I I . Bhythmicity I I I . L i g h t and temperature IV. Temperature ••••••••••••• •• V. S a l i n i t y V I . Oxygen c o n c e n t r a t i o n ••••••••••••• V I I . Pressure •••••  iv L i s t o f Tables page  Table I .  Length v a r i a t i o n with season ••••••••••••••  6  Table I I * P r o b a b i l i t y o f random odoarrenoe o f r i s e s and f a l l s i n rhythmicity data •••••• 13 Table I I I * Adjusted means of temperature Table 17* Table V.  data •••  16  Minimal l e t h a l concentration o f oxygen ....18 Summary o f seasonal comparison o f water properties of San Juan Channel, Wash, and Indian Arm, B.C. ••............•*.••• 34  L i s t of Figures  page Figure  1.  P r e s s u r e apparatus ••••  Figure  £•  Bate o f oxygen consumption vs orow&ing  Figure  3.  B i e l oxygen consumption d u r i n g summer w i t h continuous exposure t o l i g h t ••••••• 11  Figure  4*  D i e l oxygen consumption d u r i n g w i n t e r w i t h exposure t o v a r i o u s l i g h t regimes •• 12  F i g u r e C5.  9  Bate o f oxygen consumption i n l i g h t dark v s temperature •  •  ••• 11  and •••• 14  Figure  6.  Bate o f oxygen consumption vs temperature, 15  Figure  7*  Bate o f oxygen consumption vs s a l i n i t y ••• 17  Figure  8.  Figure  9*  Bate o f oxygen consumption vs oxygen concentration • ••••••• •••• 19 Bate o f oxygen consumption vs p r e s s u r e £1  vi  AGZHOWIEDGMEKTS  The by  the  author  gratefully  Department  Special  of  Zoology,  acknowledgment  Bireetor,  for  acknowledges  is  oourtesy  t i m e was  provided by  Institute  extended  University I.E.  Effordj  Br.  G . G . E . Soudder  script. Dr.  for  loan of  A . B . Aoton,  Dr.  Mr,  H . H . Webber  is  Research financial  to  C.V, also  D.J. Eandall  encouragement  Dr,  Ship the  to  and  of  the  given  manu-  by  especially  and v a r i o u s  Finnegan,  by  expressed  help  from  G . G . E . Scudder  and  acknowledged. undertaken  while  the  author  from Friday Harbor Laboratories,  (National  I.E.  and  Appreciation i s  Science  F o u n d a t i o n Summer  U n i v e r s i t y o f B r i t i s h Columbia Br,  provided  Oceanography,  c r i t i c a l reading  equipment  r e p o r t e d was  support  of Washington  grant  their  of  and Dr, A . B . Acton i s  Br,  and t h e  and I n s t i t u t e  D i s c u s s i o n w i t h and  appreciated.  and f a c i l i t i e s  Dr. W.S. Hoar, B r .  G . G . E . Soudder  Femald,  L.  U n i v e r s i t y of Washington.  of B r i t i s h Columbia.  Dr.  Robert  Friday Harbor laboratories,  of Fisheries  provided  University of B r i t i s h Columbia.  given to B r ,  Friday Harbor laboratories,  facilities  Efford).  (President's  received  University Fellowship) Fund  I*  Introduction  Crustaceans are t h e predominant  component o f marine zoo-  p l a n k t o n , b o t h i n numbers and i n s p e c i e s , and the c a l a n o i d copepods comprise t h e l a r g e s t p o r t i o n o f t h i s group 1963)*  (Raymont,  T h e r e f o r e , the r o l e o f marine c a l a n o i d copepods i n  energy u t i l i z a t i o n i n t h e ocean i s v i t a l t o our understanding o f the marine ecosystem.  Most s t u d i e s o f oxygen  consumption  o f v a r i o u s marine s p e c i e s concern t h e i n t e r p r e t a t i o n o f f o o d requirements and f e e d i n g r e l a t i o n s h i p s , and i n v o l v e the e f f e c t o f one o r at most two  environmental f a c t o r s .  Only  one  r e p o r t e d study i s concerned w i t h an e x t e n s i v e survey o f oxygen consumption w i t h r e s p e c t t o environmental f a e t o r s K i c h o l l s and O r r , 1935),  (Marshall,  I n a d d i t i o n , most o f t h e i n f o r m a t i o n  a v a i l a b l e i s r e s t r i c t e d t o s p e c i e s o c c u r r i n g i n the n o r t h e r n A t l a n t i c Ocean,  Hence, i t i s d e s i r a b l e t o o b t a i n more  knowledge o f oxygen consumption  complete  of various species.  I n view o f a h y p o t h e s i s proposed by McLaren (1963), the g e n e r a l problem o f energy u t i l i z a t i o n i n zooplankton w i t h r e f e r e n c e t o t h e i r v e r t i c a l p o s i t i o n i n a water body i s o f interest.  A c c o r d i n g t o t h i s h y p o t h e s i s , zooplankton lower i n  a water body s h o u l d use l e s s oxygen.  I f temperature  i s the  o n l y f a c t o r c o n s i d e r e d , zooplankton i n most o c e a n i c s i t u a t i o n s would decrease energy u t i l i z a t i o n w i t h i n c r e a s e i n depth. However, a t l e a s t two o t h e r environmental f a c t o r s change i n a p r e d i c t a b l e manner as a f u n c t i o n o f depth and consequently are o f a t l e a s t t h e o r e t i c a l i n t e r e s t , v i z . . l i g h t and p r e s s u r e .  2 In p a r t i c u l a r * the only published report o f the e f f e c t o f h y d r o s t a t i c p r e s s u r e on t h e oxygen consumption o f a marine z o o p l a n k t o r i n d i c a t e s t h a t oxygen consumption I n c r e a s e s w i t h i n c r e a s e i n p r e s s u r e (Hapora, 1964).  I f Napora's o b s e r v a t i o n  r e p r e s e n t s a g e n e r a l response o f zooplankton, t h e n one would not  a u t o m a t i c a l l y p r e d i c t a decrease i n energy u t i l i z a t i o n  w i t h i n c r e a s e i n depth.  Moreover, i n c o a s t a l waters o t h e r  water p r o p e r t i e s may v a r y c o n s i d e r a b l y (e.g., s a l i n i t y oxygen c o n c e n t r a t i o n ) .  and  G e n e r a l i z a t i o n o f t h e e f f e c t o f most  environmental f a c t o r s on oxygen consumption o f zooplankton i s i m p o s s i b l e and t h e r e f o r e , i n o r d e r t o conclude t h a t indeed l e s s energy i s used when deeper i n a water body,  several  f a c t o r s must be s t u d i e d . The purpose o f t h i s s t u d y i s t o i n v e s t i g a t e McLaren's h y p o t h e s i s as i t r e l a t e s t o energy u t i l i z a t i o n o f a marine o a l a n o i d oopepod by a n a l y s i s o f endogenous  change i n r a t e o f  oxygen consumption and change i n r a t e o f oxygen consumption i n response t o environmental f a c t o r s , and t o c o n t r i b u t e t o the  g e n e r a l knowledge o f oxygen consumption i n copepods.  3 II*  Materials and Methods  Copepodld V stages o f Oalanas plamehras Marakawa 1921 were used throughout the study*  C* plumohrus ocours i n the  northern P a c i f i c Ocean (Brodsky, 1950; Mori, 1937)*  In the  S t r a i t o f Georgia and neighboring waters the species i s most abundant from February to May, but may be taken from deep waters throughout most of the year*  Confusion exists on the  status o f G* plumohrus as a species d i s t i n o t from Oalanas tonsas Brady*  Brodsky (1957:49) and Zenkevitoh (1963) consider  G* plumohrus to be C* tonsus; however, Tanaka (1956) states emphatically that both are d i s t i n c t species*  In view o f t h i s  confusion, comparative data which was taken from the l i t e r a ture and which concerns C* tonans i s used l n the following only when C* plumohrus was d e a r l y the form (species) to which reference was made* Experiments reported herein were conducted at Friday Harbor Laboratories, University of Washington  (SELL) and  at the  Department of Zoology, University of B r i t i s h Columbia (UBC). Copepods used at the respective l o c a l i t i e s were c o l l e c t e d from San Juan Channel, Washington (48° 44  1  H l a t , 123° 2  1  W long)  and Indian Arm, B r i t i s h Columbia (49° 21» H lat» 122° 54» W long)*  Specimens were c o l l e c t e d by means of a ooarse meter  net using oblique and v e r t i c a l tows from depths o f 60-150 m* Water used i n experiments at FHL was taken from the running sea water system and water used at UBC was c o l l e c t e d with, a Tan Bom  b o t t l e from a depth o f 150 m at the l o c a l i t y where  copepods were collected*  A f t e r c o l l e c t i o n , copepods used f o r  4 experiments at FKL were d i l a t e d and returned to the laboratory for separation (a t r i p of 20 min), while copepods used at T3BC were separated on ship p r i o r to return*  Material was main-  tained i n aquaria containing o n f i l t e r e d sea water at 10°-12® 0 for periods varying from one day to two weeks subsequent to collection*  laboratory photoperiod t o which copepods were ex-  posed during t h i s period, was not controlled*  Ho copepods were  used for experimentation u n t i l 24 hrs a f t e r c o l l e c t i o n * Closed chambers o f 10, 35, and 50 ml and a Warburg respirometer were used to determine rate o f oxygen consumption* Prooedure used i n closed chamber experiments i s described by Conover (1956) and techniques used i n the Warburg studies are described by TJmbreit et a l i (1959)*  Copepods were acclimated  to the test chambers at 10°-12° G f o r at l e a s t 12 hrs p r i o r to test i n a l l except the 10 ml chambers* the  Copepods tested i n  10 ml chambers were used immediately a f t e r introduction  into the chambers*  A l l rates of oxygen consumption were de*  termined acutely and except when the effect of l i g h t was studied,, t e s t s were conducted i n constant darkness*  Water  used i n the experiments was f i l t e r e d using 0.45 u HA m i l l i pore f i l t e r s *  A n t i b i o t i c s were not used i n the experiments*  In closed chamber experiments, concentration o f oxygen was determined by t i t r a t i o n using the unmodified Winkler technique and by the technique described by Pamatmat (1965) using a Beckman Oxygen Analyzer (Model 777)* Copepods which were used i n the experiments were c o l * looted during different seasons (and i n one set of experiments  5 from a d i f f e r e n t (P < 0.01)  l o c a l i t y ) and t h e y v a r i e d  significantly  i n eephalothorax l e n g t h (Table I ) .  oonsamption  Rates o f oxygen  determined d a r i n g t h e s e seasons were thus c o r -  r e c t e d and expressed f o r a s t a n d a r d oephalothorax l e n g t h o f three m i l l i m e t e r s .  C o r r e c t e d and u n c o r r e c t e d v a l u e s o f r a t e s  o f oxygen consumption  are g i v e n i n Appendices  IVWTI.  Bata  f o r the e f f e c t o f crowding, r h y t h m i o i t y and p h o t o p e r i o d on r a t e o f oxygen consumption were not c o r r e c t e d s i n c e e i t h e r the re«sponses b e i n g s t u d i e d were not a f u n c t i o n o f q u a n t i t a t i v e d i f f e r e n c e s i n r a t e s o f oxygen consumption,  o r beoause  data  b e i n g oompared were c o l l e c t e d d u r i n g t h e same season and from t h e same g e n e r a l l o c a l i t y .  Rates o f oxygen consumption  of  r e p l i c a t e experiments w i t h i n t h e same season were not c o r rected f o r size variation. Although r a t e s o f oxygen consumption were determined w i t h r e s p e c t t o d i f f e r i n g l o c a l i t i e s and seasons, a t t e n t i o n i s directed p a r t i c u l a r l y , f i r s t , to the general character o f response o f oxygen consumption t o the v a r i o u s environmental f a c t o r s and second, t o the r e l a t i v e importance o f each o f these  factors. S t a t i s t i c a l a n a l y s e s used a r e d e s c r i b e d by PreuncL,  l i v e r m o r e , and M i l l e r  (1960) and Snedeeor  a n a l y s i s o f v a r i a n c e was  (1956).  When  used t o analyze more than one mean,  S i g n i f i c a n t d i f f e r e n c e s were determined by Duncan*s m u l t i p l e range comparison  (ground et al.» I960)*  new  Variances  o f means oompared by a n a l y s i s o f v a r i a n c e and by Student's "t  n  t e s t were oompared by r a t i o : : o f maximum v a r l a n o e t o  6 minimom variance (Biometrika Tables f o r Statielans, pp. 60-61 and 179).  In t h i s study. P <0#01 was used as the l e v e l of  s i g n i f i c a n c e unless otherwise stated. In addition to general methods outlined above several s p e o i f i o methods were employed. A.  Crowding.  The effect of crowding on rate of oxygen  consumption was determined by analysis of rhythmicity data i n which varying numbers o f copepods were studied i n a constant volume of water. B.  Rhythmicity.  Hourly rates o f oxygen consumption  under conditions of constant exposure to l i g h t and dark, and alternating exposure to dark and l i g h t were determined i n a manner s i m i l a r to that described by Raymont and Gauld (1951) by means of a Warburg respirometer f o r periods exdeeding 30 hrs.  Presumably an "endogenous" rhythm i n oxygen consumption  Table I . V a r i a t i o n i n length of oephalothorax of copepodid Y stages o f C. plumohrus used i n the oxygen consumption studies. Comparison o f means by Duncan's new multiple range comparison indicates a l l means are s i g n i f i c a n t l y d i f f e r e n t from eaoh other. Source FHL FED UBC  Date June 1964 May 1965 November 1965  Sample Size 36 101 34  Mean Length  (mm)  3.24 1*52 3*65  should appear i n constant conditions and an "exogenous" rhythm i n oxygen consumption should be induoed by exposure to alternating dark and l i g h t (assuming l i g h t i s a primary  7 controlling  factor).  The  the  normal photoperiod  gas  and were  conducted numbers  of  1964  copepods were  in  the  was  Light. light  The  used at  all  Section  II  used per  of  B was a l s o as  at  10° 0 a n d  constant  to  the Tests  varying during  numbers  1965  of  oxygen consumption o f range  respirometer.  about  Acute six  analyzed  same  subsequent  The to  The  5°-20° C copepods  oxygen c o n s u m p t i o n was  hrs  change.  of  copepods  to  experiment  describe  dark and t h e  any  effect  one  hr  reported effect  of  of  changes  light.  used t o  Salinity.  Standard methods  determine Water  of higher  sea water  and r e a d j u s t i n g  distilled  water.  of  the  diluting with  s a l i n i t y was to  a millipore or by  an o x y g e n  of  the  lower  than  glass  desired  ambient  distilled  or  by  Oxygen l e v e l s  electrode  repeated were  water  the  salinity with  Oxygen c o n c e n t r a t i o n s gas  Conover  temperature.  prepared by b o i l i n g  99$ n i t r o g e n  apparatus.  described by  effect  salinity  Oxygen c o n c e n t r a t i o n .  prepared by b u b b l i n g  titration  as  120 t i m e s / m i n .  a temperature  opposed t o  and w a t e r  with  of  over  s a l i n i t y was p r e p a r e d b y  F.  contained a i r  f l a s k , whereas  13° C a n d  temperatures.  Temperature.  (1956) w e r e E.  run  temperature  light  from dark to D.  were  a Warburg  a period  aoclimation to  constant  (FHL)  rate  and d a r k  measured f o r  in  of  corresponded  tested.  determined w i t h  were  rate  run at  regime  Flasks  the  copepods were  (UBC) t e s t s w e r e  C.  cycle.  shaken at  during  dark-light  glass  were filtering  determined  and r e a d j u s t e d  to  by  greater  8  q u a n t i t i e s as d e s i r e d by shaking o r b u b b l i n g w i t h a i r . Minimum oxygen c o n c e n t r a t i o n s t o l e r a b l e were estimated from t e s t s conducted  d u r i n g 1965  i n which copepods reduced  the  oxygen t o a l e t h a l c o n c e n t r a t i o n * G*  Pressure*  p l a c i n g 5-10  The  e f f e c t o f p r e s s u r e was  copepods i n a 10 ml p l a s t i c s y r i n g e *  t h e s y r i n g e was  s l o w l y extruded  the copepods, the p l u n g e r was  removed* a siphon and overflowed*  i n s e r t e d e x c l u d i n g a i r bubbles  t o 10 ml*  The needle was  apparatus The  plunger  and the volume a d j u s t e d  plugged w i t h s i l i c o n grease t o stop  oxygen exchange w i t h t h e e x t e r i o r media*  R e p l i c a t e s and  t r o l s were p l a c e d i n a p r e s s u r e chamber which was t o the d e s i r e d temperature*  P r e s s u r e was  chamber p l a c e d i n a r e f r i g e r a t o r * p e r i o d , p r e s s u r e was  Water i n  l e a v i n g a s m a l l volume w i t h  i n s e r t e d and the s y r i n g e f i l l e d was  s t u d i e d by  con*  pre-cooled  a d j u s t e d and  At the end of the  the test  r e l e a s e d q u i c k l y , the s y r i n g e s removed  and c o n c e n t r a t i o n o f oxygen i n t h e t e s t and c o n t r o l s y r i n g e s determined  by means o f an oxygen e l e c t r o d e *  r e l e a s e d from s o l u t i o n when t h e p r e s s u r e was  Oxygen was lowered*  not Tests  at d i f f e r e n t p r e s s u r e s were run f o r approximately t h e same l e n g t h o f time and under constant The p r e s s u r e apparatus  darkness*  i s shown i n F i g u r e 1*  Three  l a r g e b o l t s h o l d the ends a g a i n s t t h e p i p e and a s e a l i s of-f e c t e d by "0"  rings*  A p r e s s u r e gauge was  tapped  into  one  end and a screw top s e a l e d by an "0" r i n g i s c o n t a i n e d i n the o t h e r end*  The  screw top c o n t a i n s a screw«*piston pump whioh  created the pressure*  9  A Pressure apparatus w i t h . a n  enlarged  containing the screw-piston pump (B). chambers are  view  of  the  cap  (AV.  The control and test  introduced into the pressure chamber (C) when  cap is removed.  the  The chamber is filled with water, rhe cap is  screwed into place excluding a i r , and pressure is adjusted by means of  the pump.  Pressure is read from the gauge (D)  maintained by the  O  ring  seals (€) .  and  is  10 III* A*  Crowding,  Results  Analysis o f variance  o f the d a t a c o l l e c t e d  ( F i g u r e 2 and Appendix I ) I n d i c a t e s t h a t r a t e o f oxygen oon-» sumption d i f f e r s s i g n i f i c a n t l y w i t h r e s p e c t t o d e n s i t y and Duncan's new  population  m u l t i p l e range comparison  Indicates  t h a t r a t e o f oxygen consumption o f copepods t e s t e d a t  the  d e n s i t y o f f i v e copepods p e r ml i s s i g n i f i c a n t l y lower t h a n r a t e s determined f o r copepods t e s t e d at l e s s e r B.  Bhythmioity*  densities*  D i e l changes l n r a t e o f oxygen consump-  t i o n were determined f o r copepods a c c l i m a t i z e d t o summer and w i n t e r c o n d i t i o n s and t e s t e d i n v a r i o u s l i g h t regimes 3 and 4 and Appendix I I ) *  The  (Figure  s e t s o f d a t a were analyzed  a n a l y s i s o f v a r i a n c e t o determine t h e presence o f  by  significant  temporal changes i n r a t e o f oxygen consumption and those s e t s o f data with s i g n i f i c a n t analyzed  changes were b o t h transformed  by t h e method d e s c r i b e d by E n r l g h t  designed t o emphasize r e g u l a r t r e n d s  and E i s e n h a r t  (1965) which i s  and t o minimize the  o f random f l u c t u a t i o n s i n s e r i a l data* the s e t s o f data were analyzed  and  effect  In a d d i t i o n * each o f  by the method d e s c r i b e d by Swed  (1943) t o determine i f r i s e s and  f a l l s i n rates  o f oxygen consumption o c c u r randomly o r i n a non-random pattern* S i g n i f i c a n t changes i n r a t e s o f oxygen consumption were observed i n curves A, B,  and E*  Ho  regular trend could  a s s o c i a t e d w i t h the changes observed i n curves A and B, t h e changes i n r a t e s i n curve E may a s s o c i a t e d w i t h the  be a t l e a s t  change from dark t o l i g h t *  be but  partially Ho  significant  11  -o O  Q_ <L> Q.  o  •o  U T3 0)  CM  o  0-5 5 4 FIGURE 2.  3  2 , Copepods / m  Rate of oxygen consumption ( ± one standard errorywith respect to crowding. Copepods tested were taken from a single collection during June 1964 (FHLV  O  o a.  <v  Q.  O  U  •o  at CM  o  0-5  4  8  12 Time (hrs)  16  20  24  FIGURE 3 . Diel changes in rate of oxygen consumtion of two collections of copepods tested under constant exposure to light during June 1964 ( F H L ) . Normal photoperiodic cycle is shown on the abscissa.  2-0  o  Q_ <u Cx.  o o  •o  T3  o 0-5  20  24  4  8  12 16 20 24 Time (hrs) FIGURE 4 . Diel changes in rate of oxygen consumption of copepods under exposure to constant light (curveC\ constant dark (curve D), and alternating light-dark (curve E). C o p e p o d s tested were taken from a single collection during November 1965 (UBCV Normal photoperiodic cycle is shown on the absrissa.  13 temporal changes i n r a t e o f oxygen consumption were observed in  curves C and D.  F u r t h e r , t h e r i s e and f a l l i n r a t e o f  oxygen consumption does not occur i n any s i g n i f i c a n t (Table I I ) •  pattern  T h e r e f o r e , no rhythmic change i n r a t e o f oxygen  consumption was concluded t o be p r e s e n t . T a b l e I I . P r o b a b i l i t y o f random g r o u p i n g o f r i s e and f a l l i n r a t e o f oxygen consumption w i t h r e s p e c t t o time i n curves A-E i n F i g u r e s 3 and 4. Curve  Probability  A B C D E  C.  Light.  0.68 0*99 0.96 0.73 0.97  A n a l y s i s o f v a r i a n c e i n d i c a t e s no s i g n i f i c a n t  d i f f e r e n c e between r a t e s o f oxygen consumption o f copepods t e s t e d i n t h e presence o r absenoe o f l i g h t e i t h e r w i t h respeot to  temperature ( F i g u r e 5 and Appendix I I I ) o r w i t h r e s p e c t t o  d i e l changes (curves C and D, F i g u r e 4 ) .  However* a s i g n i f i -  cant i n c r e a s e i n r a t e o f oxygen consumption was observed when copepods were switched suddenly from dark t o l i g h t (curve E , F i g u r e 4 ) .  Subsequent means (1.30 and 1.25) were  a l s o found t o d i f f e r s i g n i f i c a n t l y  from t h e remainder o f t h e  curve. D  »  Temperature.  F o u r examples o f r a t e o f oxygen con-  sumption as a f u n c t i o n o f temperature a r e g i v e n ( F i g u r e 6 and Appendix I V ) .  Bate o f oxygen consumption i n c r e a s e d w i t h  LIGHT D  5  A  R  K  10  15  20  Temperature (° c) Rate of oxygen consumption (±one standard error) with respect exposure to light and dark at fo temperatures. Copepods tested were taken from a single collection during June 1965 ( U B C ) .  A JUNE 1964 B . JUNE 1964 MAY 1965 - A-— C D NOV 1965 • v-O-  •o  o o_  FHL FHL FHL UBC  0-8  CL. O  U  0-6 o a, CM  0-2  O  FIGURE 6.  IO Temperature Rate of oxyqen consumption ( ± one standard  error)  15 (°C)  with respect  line were collected from separate collections of copepods.  to  temperature,  2( D a t a for eacl  16 temperature when tested over a range o f 5^20° 0 .  Data f o r  l i n e C were oolleoted from a population s t a t i s t i c a l l y d i f ferent from that which l i n e s A, B, and D were c o l l e c t e d (.i*e*, the sample variance o f data f o r l i n e C d i f f e r e d from the variances o f data f o r l i n e s A, B, and D by a r a t i o with P<0.01) and l i k e l y were from a different population*  Since  the sample variance of l i n e C could not be attributed to sampling error, the l i n e i s compared no further s t a t i s t i c a l l y * Analysis o f co-variance o f l i n e s A, B,and D indicate the regression c o e f f i c i e n t s o f the l i n e s do not d i f f e r significant** l y , but elevations o f the l i n e s are s i g n i f i c a n t l y d i f f e r e n t * Duncan's new multiple range comparison indicates each o f the means when adjusted (Table III) d i f f e r s i g n i f i c a n t l y from each other* Table III*  Adjusted means of l i n e s A, B, and D, Figure 6*  Line  Mean  A B C  0.67 0*62 0.30  Adjusted Means 0.69 0.64 0.24  M o r t a l i t y occurred i n tests o f rate of oxygen consumpt i o n at 20° C during May 1965 and at 18  Q  C during Hovember  1965* indicating the upper l e t h a l temperature was approached* No mortality was observed at 20° G during June 1964* E  *  Salinity*  Analysis of variance of change l n rate o f  oxygen consumption with respect to s a l i n i t y (Figure 7 and  1-5  O Q_  •o  O) OL  O O  JULY 1964  CM  MAY 1965  0-5  o  O  -•tW-!">!"  IO  15  20  25 Salinity (parts  FIGURE  7-  Rate of oxygen consumption collections of copepods  30 per  45  40  thousand)  ( ± one standard error)  (FHL).  35  with respect to salinity  of  two  18 Appendix V) i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e i n 1964 d a t a , b a t i n d i c a t e s s i g n i f i c a n t v a r i a t i o n i n t h e 1965 data* Duncan's new m u l t i p l e range comparison i n d i c a t e s r a t e i s s i g n i f i c a n t l y h i g h e r a t 10 p a r t s p e r thousand (ppt) and s i g n i f i c a n t l y lower at 45 ppt d a r i n g 1965. Two-way a n a l y s i s o f v a r i a n c e o f r a t e s t e s t e d at 20, 25, 30, and 35 ppt d a r i n g 1964  and 1965 i n d i c a t e s no s i g n i f i c a n t d i f f e r e n c e w i t h  s a l i n i t y o r time. Wm  Oxygen c o n c e n t r a t i o n .  S i g n i f i c a n t change i n r a t e  o f oxygen consumption w i t h r e s p e c t t o oxygen c o n c e n t r a t i o n and temperature was n o t observed observed  d u r i n g May 1965, b u t was  a t 3° G and 1 8 ° G d u r i n g lovember 1965 ( M g u r e 8  and Appendix Y I ) .  A t b o t h temperatures d u r i n g November 1965*  r a t e o f oxygen consumption was r e s t r i c t e d by c o n c e n t r a t i o n s o f oxygen l e s s than approximately  3 co oxygen p e r l i t e r .  Minimal l e t h a l oxygen c o n c e n t r a t i o n s a t t h r e e temperatures were determined d u r i n g November 1965 (Table I V ) .  Lethal  minimum oxygen c o n c e n t r a t i o n s d i d not d i f f e r w i t h temperature. Table IV. Minimal oxygen c o n c e n t r a t i o n s (oo Og/l) t o l e r a b l e at t h r e e temperatures f o r copepods t a k e n from I n d i a n Arm, B.C.  Mean  12° G  18° d  0.80 0.70  0.80 0*70 0.65 1.22  0.85 0.85 0*90 1.00 0.87  0.75  0.84  0.89  19  2  3  4  5  6  Oxygen Concentration (cc O2 / l i t e r ) FIGURE  8- Rate of oxygen consumption ( ± one standard error) with respect to oxygen concentration and temperature. Copepods tested at 5 , 10°, 2 0 ° C . w e r e taken from a single collection during May 1965 (FHL) and copepods tested at 3°. 12 . and 18° C were taken from a single collection during November 1965 ( U B C ) .  so G.  Pressare.  Hate o f oxygen consumption was not  signi*  f i c a n t l y ohanged by p r e s s u r e s e q u i v a l e n t t o a depth o f 400 at 10° o r 12° 0 ( F i g u r e 9 and Appendix V I I ) . d a t a were not l i n e a r l y b i l i t y of linear  m  F u r t h e r , the  c o r r e l a t e d at 10° C and t h e proba-  c o r r e l a t i o n at 12° C was P<0.05 (shown b y  a dashed l i n e i n F i g u r e 9).  However, i n a l l experiments r a t e  o f oxygen consumption decreased w i t h i n c r e a s e d p r e s s u r e and f o r t h a t reason t h e dashed l i n e was b y l e a s t squares.  f i t t e d t o the 12° C d a t a  0-8  o  O IO  O  c  I2°C  0-6  O 0-4  O  O  O  0  O  o  o  O  -  o 0-2  O  12 C O  o  O IO  O  20 Pressure  FIGURE  9>  Rate  40  30  (atmospheres)  of oxygen consumption with respect to  pressure.  temperatures were taken from a single collection  during  Copepods November  tested at the two 1965  (UBC).  22 IV.  Discussion  C o n s i d e r a t i o n o f t h e v a r i a t i o n s i n r a t e o f oxygen consumption t o endogenous and environmental  f a c t o r s i s important  (1) i n order t o e v a l u a t e t h e e f f e c t o f t e c h n i q u e s used on t h e d a t a o b t a i n e d , (2) i n o r d e r t o evaluate t h e e f f e c t and t o i n t e r p r e t t h e meohanism o f a c t i o n o f p a r t i c u l a r f a c t o r s on oxygen consumption and (3) i n o r d e r t o e v a l u a t e oxygen u t i l i z a t i o n and requirements A,  i n t h e n a t u r a l environment,  Considerations o f technique.  ture, s a l i n i t y ,  The e f f e c t o f tempera-  l i g h t and d e n s i t y o f experimental  animals,  on r a t e o f oxygen consumption i s g e n e r a l l y a p p r e c i a t e d ( P r o s s e r and Brown, 1961),  I n a d d i t i o n , i f r e g u l a r endogenous  changes i n r a t e o f oxygen consumption a r e p r e s e n t , data which are t o he compared must be s e l e c t e d from t h e same stage o f t h e rhythm.  I r r e g u l a r endogenous changes may be removed b y  continuous m o n i t o r i n g and s e l e c t i o n o f comparable data, when the necessary  equipment i s a v a i l a b l e .  P r e s s u r e i s o r d i n a r i l y maintained a t one atmosphere. However, when p r e s s u r e i s t e s t e d as t h e v a r i a b l e a f f e c t i n g r a t e o f oxygen consumption o f a q u a t i c organisms and t h e ex* p e r i m e n t a l ohamber must be removed from under p r e s s u r e t o analyze oxygen, c a u t i o n must be employed t o ensure oxygen i s not r e l e a s e d from s o l u t i o n due t o temperature change as pressure i s released.  C o n t r o l experiments i n d i c a t e d t h a t  sudden r e l e a s e o f p r e s s u r e e q u i v a l e n t t o 40 atm t o g e t h e r w i t h t h e change from 10° C t o about 20° G d u r i n g  analysis  23 (enoompasslng a time p e r i o d o f about 10 min) i n r e l e a s e o f oxygen from s o l u t i o n . oxygen c o n c e n t r a t i o n , one 40 atm  f o r two  kept at one  Two  d i d not  solutions of  atm  and one  h r s f o l l o w e d "by sudden r e l e a s e o f  agreed w i t h i n one  per cent  (100$  on a Beckman Oxygen A n a l y z e r , t h e experimental  saturation s  Model 777,  result equal  kept at pressure,  full  scale)  Therefore,  under  c o n d i t i o n s used, r e l e a s e o f oxygen from  s o l u t i o n d i d not prove to "be a problem. The  importance o f the e f f e c t o f the e x c i t a t o r y s t a t e o f  copepods on r a t e o f oxygen consumption (Berner, not be  1962:636) can  emphasized too s t r o n g l y i f r e p r o d u c i b l e r e s u l t s are t o  be o b t a i n e d .  E x c i t a t i o n o f the copepods by t r a n s f e r o r by result i n a  d i r e c t exposure t o an environmental v a r i a b l e , may q u a n t i t a t i v e l y unpredictable consumption (Ealorow, 1963;  overshoot response o f oxygen Grainger,  1958)*  experiment i s o f s h o r t d u r a t i o n and the  I f the  chamber volume i s  s m a l l i n r e l a t i o n t o the number o f copepods t e s t e d , r a t e o f oxygen consumption d u r i n g overshoot may resultant rate. duration  strongly bias  the  In c o n t r a s t , when experiments are l o n g i n  (achieved  i n c l o s e d systems by having  a large ratio  o f water and hence oxygen t o organism t e s t e d ) time spent i n overshoot i s s h o r t i n comparison t o the and  total  l e n g t h o f time  consequently t h e measured r a t e o f oxygen consumption i s  l e s s b i a s e d by change i n r a t e d a r i n g overshoot. overshoot response may oopepods t o the t e s t B e m e r , 1962),  Some o f the  be minimized by a c c l i m a t i n g  chambers p r i o r t o t e s t  the  (Conoverj  1956;  24 I n th©  present study the  e f f e o t s o f the v a r i a b l e s  r a t e s measured were minimized by m a i n t a i n i n g the constant o r not  allowing  on  variables  them t o v a r y t o l e v e l s at which  oxygen consumption i s a f f e c t e d .  I r r e g u l a r endogenous changes  oould not be  removed s i n c e i n most oases r a t e o f oxygen  sumption was  not monitored  The  con'"  continuously.  desire for better r e p r o d u c i b i l i t y of results  and  i the a b i l i t y t o c o r r e c t s p u r i o u s changes i n r a t e s w i l l necess i t a t e , i n subsequent i n v e s t i g a t i o n s , continuous m o n i t o r i n g o f oxygen consumption ( T e a l and  Halcrow, 1962  and  Halorow,  1963). B.  E f f e c t of factors.  The  e f f e c t of population  density  and l i g h t were s t u d i e d p r i m a r i l y t o determine i f e i t h e r s i g n i f i c a n t l y a f f e c t s r a t e o f oxygen consumption. sence o f endogenous rhythms was measurements should be  The  pre-  i n v e s t i g a t e d t o determine i f  r e s t r i c t e d t o a p a r t i c u l a r time  period  and  t o t e s t i f an endogenous rhythm i n locomotor a c t i v i t y  was  present.  S a l i n i t y , oxygen c o n c e n t r a t i o n ,  temperature were i n v e s t i g a t e d  pressure,*and  i n order to describe  how  these  major environmental v a r i a b l e s a f f e c t oxygen consumption. Increase i n p o p u l a t i o n  d e n s i t y r e s u l t s i n decrease i n  r a t e o f oxygen consumption o f 0. plumohrus  as i s  f o r Oalanas finmarohious (Gunner) ( Z e i s s , 1963). 0. plumohrus  reported However,  i s g e n e r a l l y l e s s s e n s i t i v e t o orowding.  Z e i s s s t a t e d the decrease i n oxygen consumption o f 0. and  f i n m a r c h l e u s i n d i c a t e d the suggested i n c r e a s e d  influence  o f some o t h e r f a c t o r  metabolite concentration.  The  data  25 presented i n Figure hypothesis;  2 might appear t o agree w i t h t h i s  however, i f m e t a b o l i t e accumulation i s the  n i f i c a n t f a c t o r decreasing  r a t e o f oxygen consumption*  sigone  would expect a decrease i n r a t e o f oxygen consumption w i t h time at each d e n s i t y t e s t e d (or a l l o w i n g e f f e c t * one  for a  threshhold  s h o u l d observe a decrease i n r a t e above a p a r -  t i c u l a r density)*  But* a n a l y s i s o f the  24 h o u r l y measure-  ments o f r a t e o f oxygen consumption at each d e n s i t y  indicates  t h a t at d e n s i t i e s o f 4-5  differ?  copepods / ml r a t e d i d not  s i g n i f i c a n t l y w i t h time ( i * e * * r a t e s measured d u r i n g f i r s t 12 h r s were the h r s ) and  same as measured d u r i n g the  copepods t e s t e d at a c o n c e n t r a t i o n  copepods / ml i n c r e a s e d  the i n c r e a s e  12  r a t e o f oxygen consumption w i t h  f i r s t 12 h r s ) *  One  significantly  might a l s o argue t h a t  i n r a t e w i t h time r e p r e s e n t s  crease i n r a t e o f oxygen consumption and tainance  second  o f l e s s than 4  time ( i * e * * r a t e d u r i n g the second 12 h r s was h i g h e r t h a n the  the  an endogenous i n consequently maln-  o f a constant r a t e i s a c t u a l l y a r e l a t i v e decrease*  but  i t s h o u l d be  4-5  copepods / ml  observed t h a t t h r e e d e n s i t i e s t e s t e d i n the d e n s i t y range d i d not  differ  from the d e n s i t y o f l e s s than 4 copepods / ml* maintainance o f a constant r a t e cannot be r e l a t i v e decrease* effect of population  The  significantly Hence,  i n t e r p r e t e d as  a  d a t a p r e s e n t e d l n t h i s study f o r the  d e n s i t y on r a t e o f oxygen consumption  o f 0* plumohrus* t h e r e f o r e , do not  support the  t h a t m e t a b o l i t e accumulation i s r e s p o n s i b l e r a t e o f oxygen consumption.  hypothesis  f o r deorease l n  At p r e s e n t , I can o f f e r  no  26 a l t e r n a t i v e e x p l a n a t i o n f o r t h e observed decrease* The e f f e c t o f l i g h t was i n p a r t i n v e s t i g a t e d w i t h t h e a n a l y s i s f o r endogenous changes l n oxygen consumption*  Ho  d i f f e r e n c e l n r a t e o f oxygen consumption between copepots kept i n continuous l i g h t and continuous dark c o u l d be demon* strated*  However, i n one s e t o f experiments ohange from  dark t o l i g h t d i d r e s u l t i n a s i g n i f i c a n t i n c r e a s e i n r a t e o f oxygen consumption*  Conover  (1956) r e p o r t e d no e f f e c t o f  presence o r absence o f l i g h t on r a t e o f oxygen consumption o f A o a r t i a o l a u s i G l e s b r e o h t and A c a r t i a tonaa Dana and i n con* t r a s t M a r s h a l l e t a l * (1935) r e p o r t a marked e f f e c t o f l i g h t on r a t e o f oxygen consumption o f C* f i n m a r o h i o u s *  Marshall  et a l * (1935) e l i m i n a t e d 17V l i g h t as t h e f a o t o r c a u s i n g s i g n i f i c a n t i n c r e a s e i n r a t e o f oxygen consumption, although exposure t o UV l i g h t d i d r e s u l t i n i n c r e a s e d m o r t a l i t y * B i n g l e b e r g (1961, 1964) has demonstrated t h a t d i f f e r e n t  Also., light  i n t e n s i t i e s and r a t e s o f change o f i n t e n s i t y o f l a b o r a t o r y i l l u m i n a t i o n can a f f e c t looomotory a c t i v i t y o f t h e c l a d o o e r a n Daphnla magna S t r a u s *  I n most s t u d i e s o f oxygen  consumption*  t h e e f f e c t o f l i g h t o r dark i s not determined, b u t r a t h e r experimental c o n d i t i o n s a r e m a i n t a i n e d uniform*  Since l i g h t  i s c o r r e l a t e d w i t h so many responses (e.g.., Gushing, 1951; Lewis, 1959; Moore and O'Berry, 1957; B i n g l e b e r g , 1961,1964) more i n v e s t i g a t i o n c o n c e r n i n g i t s p h y s i o l o g i c a l e f f e c t i s warranted* H a r r i s (1963) r e p o r t e d e x p e r i m e n t a l demonstration o f an i n t r i n s i c rhythm i n locomotor a c t i v i t y i n t h e z o o p l a n k t o r s  27 D. magna and £• finmarehious and correlated these oircadian rhythms with v e r t i c a l migration,  Moore and 0'Berry (1957)  also argue f o r the presence of an endogenous rhythm i n association with v e r t i c a l migration.  I f an endogenous rhythm  related to v e r t i c a l migration i s a general phenomen of zoo* plankton and i f the rhythm i s related to locomotor a c t i v i t y , i t s presence should be testable by measurement of oxygen consumption.  However* 0. plumohrus demonstrates no regular  s i g n i f i c a n t change i n rate of oxygen consumption.  Therefore*  one might oonclude that C. plumohrus does not migrate, but Zenkevitoh (1963:793) reports Oalanas tonsas (0. plumohrus) to be both a d a i l y and seasonal v e r t i c a l migrator.  Alter-  native explanations of the absence o f a rhythm cannot be excluded.  Other possible explanations are (1) the populations  of oopepods tested may have been asynchronous, (2) the rhythm may be ephemeral and henoe disappears when the copepods are taken i n t o the laboratory and tested i n the Warburg respirometer, (3) the rhythm might not be r e l a t e d to locomotor a c t i v i t y , (4) active v e r t i c a l migration might only be a funotion o f l e s s than h a l f o f the population (Moore, 1955; Moore and 0'Berry, 1957) and therefore animals tested might have been selected from non-migrators present i n the same populations or (5) the method of monitoring oxygen consumption may not be sensitive enough.  However, i t should be kept l n  mind that the response measured by Harris was at least a "semi-persistent" population phenomena measured under laboratory conditions.  S t i l l another p o s s i b i l i t y i s that Harris  28 a c t u a l l y measured an endogenous rhythm i n maintainanoe o f v e r t i c a l p o s i t i o n r a t h e r t h a n a locomotor rhythm s i n c e down* ward movement ( e s p e c i a l l y i n n a t u r e ) need not n e c e s s a r i l y imply o n l y p a s s i v e s i n k i n g . Thus, w i t h r e f e r e n c e t o t h e e f f e c t o f t h e remaining environmental f a c t o r s s t u d i e d on measurement o f oxygen oon* sumption, crowding i s a s i g n i f i c a n t f a c t o r o n l y a t concent r a t i o n s when d e n s i t y i s e q u a l t o o r g r e a t e r t h a n f i v e copepods / ml, n e i t h e r l i g h t n o r dark cause d i f f e r e n c e u n l e s s the copepods  a r e changed from one t o t h e o t h e r d u r i n g o r j u s t  p r i o r t o t h e t e s t s , and t e s t s need n o t he r e s t r i c t e d t o a p a r t i c u l a r time o f t h e day. However, d u r i n g t h e summer random s i g n i f i c a n t i n c r e a s e s i n r a t e o f oxygen consumption  do o c c u r *  S i n c e oxygen consumption was c a l c u l a t e d from measurements t a k e n at t h e t e r m i n a t i o n o f t h e t e s t , r a t e s c o u l d not he c o r r e c t e d f o r t h e s e changes*  Furthermore, i t i s not known i f  t h e s e changes a r e " r e a l " o r i f t h e y merely r e f l e c t t h e experimental technique*  Hence, t h e d a t a must he c o n s i d e r e d  a maximum e s t i m a t e o f oxygen  consumption*  Response t o temperature i s e n l i g h t e n i n g and c o n s i d e r a t i o n o f t h i s response i s important t o t h e remainder o f the data* Bate o f oxygen consumption i n o r e a s e d "both l i n e a r l y  ( F i g u r e 6)  and n o n - l i n e a r l y ( F i g u r e 5) over a temperature range o f 5°-20° 0 when p l o t t e d i d e n t i c a l l y and as w e l l * t h e l i n e a r response d i f f e r e d b y sample v a r i a n c e and b y e l e v a t i o n ference*  dif-  One o f the l i n e s d i f f e r i n g b y e l e v a t i o n was d e r i v e d  from copepods  c o l l e c t e d from a d i f f e r e n t season and l o c a l i t y ,  29 d i s a l l o w i n g the c o n c l u s i o n t h a t a q u a n t i t a t i v e  difference  i n d i c a t e s a b i o l o g i c a l d i f f e r e n c e ( t h i s b e i n g due t o seas o n a l a d a p t a t i o n , see Oonover (1959) and M a r s h a l l and G r r (1958))*  However, the d i f f e r e n c e i n the l o c a l i t y s t r o n g l y  i m p l i e s t h a t the p o p u l a t i o n s are b i o l o g i c a l l y  distinct.  Thus, v a r i o u s aspects o f each o f the s e t s o f oxygen consumpt i o n data suggest t h a t each o f the s e t s o f d a t a i s c o l l e c t e d from a d i f f e r e n t b i o l o g i c a l p o p u l a t i o n . o f the s e t s o f temperature  In a d d i t i o n , each  data i n d i c a t e s a d i f f e r e n t  history  o f thermal a c c l i m a t i z a t i o n i n each o f the p o p u l a t i o n s s t u d i e d . The  s l o p e s o f the l i n e s however, do not v a r y , t h e r e b y  i n d i c a t i n g t h a t Q^  0  tested.  does not change w i t h season o r p o p u l a t i o n  The g e n e r a l response  of non-proportional increase or  decrease o f r a t e o f oxygen consumption at 20° 6 i n d i c a t e s t h a t t h i s temperature The  i s near the upper l e t h a l  limit.  e f f e c t o f s a l i n i t y on r a t e o f oxygen consumption o f  copepods i s v a r i a b l e .  M a r s h a l l et a l . (1935) and Anraku  (1964) r e p o r t r a t e o f oxygen consumption o f 0. decreases w i t h decrease i n s a l i n i t y . r e p o r t e d f o r Centropaa;ea  finmarehious  A s i m i l a r decrease i s  hamatus ( L i l l j e b o r g ) (AnrakUi  1964).  I n c o n t r a s t , l a n c e (1965) r e p o r t s a c o n s i s t e n t i n c r e a s e i n r a t e o f oxygen consumption o f A. t b n s a w i t h decrease i n salinity.  0. plumohrus appears t o respond i n an i n t e r m e d i a t e  f a s h i o n w i t h no s i g n i f i c a n t change i n r a t e o f oxygen consumpt i o n over a range o f 20*»35 ppt w i t h a s i g n i f i c a n t i n c r e a s e at 10 ppt and a s i g n i f i c a n t decrease at 45 p p t . d a t a from Calanus  Comparative  spp. and P I e u r o b r a b h l a babhel A g a s s i z i n d i c a t e  30 a constant  o r s l i g h t l y i n c r e a s i n g r a t e o f oxygen consumption  over a range o f 80-35 ppt and a marked i n c r e a s e i n r a t e at lower o r h i g h e r s a l i n i t i e s  (Topping,  unpublished  data)#  Sample v a r i a n c e o f the two  s e t s o f data presented were un«*  equal i n d i c a t i n g t h a t t h e p o p u l a t i o n from which the data were c o l l e c t e d are b i o l o g i c a l l y d i f f e r e n t . sponses are not The  quantitatively  However, the two  re-  different.  manner i n which s a l i n i t y a f f e c t s oxygen consump-  t i o n o f crustaceans  i s s t i l l disputed  (e_.gj. * S c h l i e p e r ,  P l e m i s t e r and P l e m i s t e r , 1951;  l o f t s , 1956;  P o t t s and P a r r y , 1964)•  (1965) r e p o r t e d maintalnanoe  lance  Gross,  1929;  1957;  o f s l i g h t h y p e r t o n i o i t y w i t h decrease i n s a l i n i t y i n A. and i n view o f c o n s i d e r a t i o n s r e p o r t e d by P o t t s  (1954), t h i s  response should r e q u i r e l i t t l e energy u t i l i z a t i o n . nique employed i s d i f f i c u l t  The  tech-  and the d a t a r e q u i r e v e r i f i c a t i o n .  I t remains p o s s i b l e t h a t i n c r e a s e d r a t e may b u r s t s o f locomotor  tonsa  be due t o  initial  activity.  That oxygen c o n c e n t r a t i o n may  act t o r e g u l a t e r a t e o f  oxygen consumption i s w e l l known ( P r o s s e r and Brown, 1961). However, evidence  t h a t oxygen c o n c e n t r a t i o n may  act t o a f f e c t  oxygen consumption o f copepods i s r e s t r i c t e d to one ( M a r s h a l l et a l . , 1935).  The  present  study  report  indicates that  r a t e o f oxygen consumption o f 0. plumchrns i s r e s t r i c t e d  by  c o n c e n t r a t i o n s l e s s than 3 cc oxygen per l i t e r and t h a t the minimum l e t h a l c o n c e n t r a t i o n i s about one The  1964  co oxygen per  liter.  data do not c l e a r l y demonstrate t h i s o b s e r v a t i o n  cause r a t e o f oxygen consumption o f these copepods was  be-  at a  31 minimal l e v e l and the d i f f e r e n c e i n r a t e dae t o oxygen c o n c e n t r a t i o n was  small.  copepods t e s t e d i n May  A l s o , when the r a t e s o f  1965  the  were c o r r e c t e d f o r s i z e d i f f e r -  ence, experimental e r r o r as w e l l as r a t e o f oxygen consumpt i o n was  m u l t i p l i e d "by the same f a c t o r and  i n r a t e was  shown.  hence no  S i n c e the r a t e s o f w i n t e r a c c l i m a t i z e d  animals i s lower t h a n summer animals, the above imply t h a t t h e r e would be a c o r r e s p o n d i n g l y o f oxygen c o n c e n t r a t i o n . and P. b a c h e i  are not 1-2  considerations  smaller e f f e c t  Comparative data f o r Calanus  i n d i c a t e a response s i m i l a r t o t h a t  f o r C_, plumohrus.  difference  reported  However, r a t e s of both p l a n k t o r s  reduced u n t i l oxygen c o n c e n t r a t i o n s  oo oxygen per l i t e r .  The  data may  I n d i c a t e t h a t oxygen c o n c e n t r a t i o n i n most o f the open ocean, but i n c o a s t a l areas and  spp,  at 5° C  are reduced t o  be i n t e r p r e t e d to  i s e s s e n t i a l l y unimportant  the f a c t o r may  c e r t a i n l y should be  be  important  considered  in  fresh-water environments. P r e s s u r e has been proposed to be t o marine zooplankton (Moore and O'Berry, 1957), but  again  a f a c t o r o f importance  Corwin* 1956;  evidence o f the e f f e c t o f  on oxygen consumption i s r e s t r i c t e d to one 1964),  Moore  and pressure  study (Uapora,  JSTapora r e p o r t e d t h a t r a t e o f oxygen consumption o f  the prawn S y s t e l l a s p i s d e b i l i s M.-Bdwards i n c r e a s e d i n c r e a s e i n h y d r o s t a t i c pressure e f f e c t of pressure ture.  Teal  and t h a t at about 900  i s equal and o p p o s i t e  ( i n manuscript) has  with m  the  t o t h a t o f tempera-  s t u d i e d the e f f e o t o f  sure on r a t e o f oxygen consumption o f v a r i o u s l a r g e r  pres-  32 orustaoeans and euphausids  and has o b t a i n e d v a r i a b l e r e s u l t s  (e*£*, Thysanopoda monooantha Ortman i n c r e a s e s r a t e o f oxygen consumption w i t h i n c r e a s e i n p r e s s u r e , T. t r i o n s p i d a M. Edw* undergoes e s s e n t i a l l y noi change i n r a t e and T. o b t u s i f r o n s Sars decreases r a t e 0*  )• The r a t e o f oxygen consumption o f  plumchrus was not s i g n i f i c a n t l y changed w i t h i n c r e a s e i n  p r e s s u r e equal t o about 40 atm ( o r e q u i v a l e n t t o about 400m)• I observed a s i m i l a r response i n a fresh-water Baphnia  daphnid  spp* which was c o l l e c t e d from a l a k e w i t h a maximum  depth not exceeding 15 m*  I n view o f t h e r e s u l t s thus f a r  o b t a i n e d and because o f t h e p a u c i t y o f t a x a t e s t e d , g e n e r a l i z a t i o n o f t h e e f f e c t o f p r e s s u r e on oxygen consumption o f p l a n k t o n i e crustaceans i s i m p o s s i b l e *  However, e f f e c t o f  p r e s s u r e on oxygen consumption o f C* plumchrus may have been masked by t h e technique employed (see Sec. I I G and Sec* IV A)*  I f t h e e f f e c t o f p r e s s u r e i s hidden* t h e n t h e r e g r e s s i o n  l i n e shown i n F i g u r e 9 f o r t h e 12° C data ( s i g n i f i c a n t a t P < 0*05) may g i v e a b e t t e r i n t e r p r e t a t i o n o f t h e e f f e c t o f pressure*  I n t h i s case* t h e d a t a p r e s e n t e d g i v e an i n t e r -  p r e t a t i o n o f t h e minimum e f f e c t o f p r e s s u r e * C*  Oxygen u t i l i z a t i o n i n n a t u r e *  I n i t i a l l y , t h e temp-  e r a t u r e data i n d i o a t e t h a t d a t a c o l l e c t e d from copepods t a k e n from d i f f e r e n t c o l l e c t i o n s ( i n t h i s study equal d i f f e r e n t sample dates) may be from d i f f e r e n t b i o l o g i c a l p o p u l a t i o n s * S i n c e t h e e f f e c t o f a l l f a c t o r s were n o t determined  on a  s i n g l e c o l l e c t i o n o f copepods, t h e s e p a r a t e responses may not be grouped  and argued t o r e p r e s e n t t h e response o f a s i n g l e  33 p o p u l a t i o n o f G* plumohrus*  Bather*  a g e n e r a l i z e d response  o f C. plumohrus* not s p e c i f i c t o a p a r t i c u l a r p o p u l a t i o n , t o the f a c t o r s t e s t e d i s obtained*  T h i s i s i n no way  detri-  mental t o i n t e r p r e t a t i o n o f t h e g e n e r a l p i c t u r e o f  energy  u t i l i z a t i o n o f G* plumohrus i n nature* The  environmental  s a l i n i t y * temperature  f a c t o r s c o n s i d e r e d i n t h i s study (e.g*» o r oxygen c o n c e n t r a t i o n may  v a r y ac-  c o r d i n g t o the p a r t i c u l a r p a r t of the marine environment studied*  L i g h t and p r e s s u r e w i l l always decrease and i n -  crease r e s p e c t i v e l y w i t h i n c r e a s e i n depth*  Temperature w i l l  a l s o g e n e r a l l y decrease w i t h l n e r e a s e i n depth, except i n areas o f extreme mixing wherein temperature t i a l l y constant or w i t h a t e r m a l i n v e r s i o n *  may  remain essen-  S a l i n i t y and  ox-  ygen c o n c e n t r a t i o n w i l l remain e s s e n t i a l l y constant w i t h i n c r e a s e i n depth i n t h e open ocean, but i n c o a s t a l  situa-  t i o n s , p a r t i c u l a r l y f j o r d s and i n l e t s , s a l i n i t y may  increase  and oxygen c o n c e n t r a t i o n decrease markedly w i t h  depth*  T h e r e f o r e , a c c o r d i n g t o v a r i a n c e o f the environmental c o n s i d e r e d , oxygen consumption might v a r y w i t h depth c o r d i n g t o t h e environment.  Comparison o f the two  factors ac-  localities  from which C, plumohrus were o o l l e c t e d f o r t h i s study are given i n Table Zenkevitoh  V, (1963) r e p o r t e d t h a t Oalanas tonsus  plumchrns) o c c u r r i n g i n t h e n o r t h P a c i f i o migrates b o t h s e a s o n a l l y and d i u m a l l y *  (Calanus vertically  T h e r e f o r e , MoLaren s (1963) f  hypothesis t h a t the adaptive value o f v e r t i c a l migration of zooplankton i s t o (1) be p r e s e n t i n o r near the  euphotio  34 Table V, Summary o f water properties with depth and season i n San Juan Channel and Indian Arm (Tulley and Bodimead 1957; Waldiohuk, 1957; Gilmartin, 1962). t  Depth (m)  Temperature (°  Salinity (ppt)  G)  Oxygen (ocOg/l)  San Juan Channel: June'50 Winter 0 13. 6 150 8 6  June 50 . 24.0 30.6  Indian Arm: June 59 Uov,»57 0 158100 7 7 200 7 7  Sum.Max Win.Min 16 15 28 27 28 28  1  1  Feb. 50 28.5 30.4 1  June*31 Feb/31 8.2. 7.5 6.0 6.0 May '59 Oct. 59 9.0 6.0 4.5 3.0 2.0 2.2 1  zone to feed and yet (2) t o sink lower i n the water body where* primarily due to lower temperature, l e s s energy w i l l be used and (3) the energy i s shunted to growth of larger more fecund plankton, which i n turn (4) produce more o f f s p r i n g allowing seleotion f o r v e r t i c a l l y migrating forms, i s o f special s i g n i ficance.  Migration to or through discontinuity layers w i l l  presumably r e s u l t i n exposure o f the plankton to wide ranges o f environmental factors and overshoot i n physiological adjustment t o these properties should r e s u l t .  Therefore,  overshoot i n rate of oxygen consumption (although maximizing the quantity o f response to a p a r t i c u l a r factor) i s considered part of the normal response and hence* i s not removed from the r e s u l t s presented i n t h i s study. Due to lack o f better data, responses to the environmental factors are considered to be additive ( f o r l i m i t s t o t h i s assumption see Kinne (1964) and Hapora (1964)).  35  9L* Pl.tuoehroB i n the open ocean shoald decrease oxygen u t i l i z a t i o n with depth p r i m a r i l y due to temperature.  In a  coastal s i t u a t i o n such as San Juan Channel, rate o f oxygen consumption may deorease s l i g h t l y during summer with depth due to decrease i n temperature, hut should undergo e s s e n t i a l l y no change during most o f the year.  Consideration of temperature,  s a l i n i t y and oxygen concentration i n another coastal body of water (Indian Arm, a B r i t i s h Columbia  fjord) also i n -  dicates rate o f oxygen consumption should decrease with depth. However, i n t h i s case oxygen consumption should decrease p r i m a r i l y because of oxygen concentration since higher temperatures are above the halooline and the surface s a l i n i t i e s reported should be l e t h a l t o C. plumohrus. c l i n e , temperature decreases l i t t l e . the  Below the halo-  Therefore, i n eaoh o f  situations described the copepod G. plumohrus should de-  crease rate of oxygen consumption with depth, except poss i b l y when passing through a thermal inversion i n the water body.  Consequently* change i n rate of oxygen consumption  with depth i s i n general agreement with McLaren's hypothesis of energy u t i l i z a t i o n .  However, i n p a r t i c u l a r ooastal  situations oxygen concentration or s a l i n i t y might act i n concert with temperature to decrease energy u t i l i z a t i o n .  This  conclusion might appear to be a "truism", but i n view of Hapora's  (1964) report and Teal's tentative r e s u l t s , such a  conclusion i s not axiomatic and cannot therefore necessarily be generalized t o other species of zooplankton. Various p e c u l i a r i t i e s of v e r t i c a l migration observed  36  b o t h i n the f i e l d and i n the l a b o r a t o r y (Hansen, 1951; 1957;  l a n c e , 1962; Moore and O'Berry*  Harder,  1957), t o g e t h e r w i t h  t h e r e p o r t t h a t zooplankton w i l l tend to r e g u l a t e t h e i r d i s t r i b u t i o n such t h a t energy u t i l i z a t i o n i s maintained at a constant r a t e  (Bishop, 1964)  suggest t h a t i n t e r p r e t a t i o n o f  s p e c i f i c p a t t e r n s o f p l a n k t o n d i s t r i b u t i o n and movement i n terms o f p h y s i o l o g y and p a r t i c u l a r l y energy may be f r u i t f u l .  utilization  37 V. 1*  Summary  Oxygen consumption o f C_. plumohrus with respect to environmental and endogenous changes was studied.  Copepodid 7  stages were used throughout the study and speoimens were collected from San Juan Channel, Washington and Indian Arm, B r i t i s h Columbia, 2.  Bates o f oxygen consumption were determined using standard closed chamber technique described by Conover (1956) and Warburg respirometry.  3.  Bate o f oxygen consumption o f C. plumohrus i s l i m i t e d by extreme population densities and t h i s l i m i t a t i o n i s not attributable to metabolite accumulation.  4.  The r e l a t i o n between volume o f sample ohamber and duration of t e s t i s important i n evaluating rate of oxygen consumption.  5.  Temperature data indicate that f o r various measurements of oxygen consumption to be comparable, rates must be measured on the same c o l l e c t i o n of copepods.  Either due  to the r e a l d i s t r i b u t i o n of copepods or due t o the laok of r e p r o d u c i b i l i t y of measuring rate of oxygen consumpt i o n of copepods* data from subsequent oolleotions within the same season and from the same l o c a l i t y are s t a t i s t i c a l l y different. 6.  Changes i n rate o f oxygen consumption of 0.' plumohrus i n response to environmental and endogenous faotors may be grossly summarized as follows: a.  Bate o f oxygen consumption i s s i g n i f i c a n t l y decreased  38 "by p o p u l a t i o n d e n s i t i e s o f 5 o r more copepods / ml, b.  Regular endogenous changes i n r a t e o f oxygen consumption do not appear t o o c c u r ,  c.  The presence o r absence o f l i g h t does not cantly affect  signifi-  r a t e o f oxygen consumption, but  from one c o n d i t i o n t o the o t h e r may  change  cause a s i g n i f i -  cant i n c r e a s e , d.  Hate o f oxygen consumption may be d e s c r i b e d as d i r e c t l y p r o p o r t i o n a l (being v a r i o u s l y l i n e a r  and  non»linear) t o temperature throughout t h e range o f 5°-20° e.  0.  Hate o f oxygen consumption does not v a r y  significantly  over a s a l i n i t y range o f 20-35 p p t , but i n c r e a s e d at 10 ppt and decreased at 45 p p t , f.  Hate o f oxygen consumption decreases t o a minimal r a t e below an oxygen c o n c e n t r a t i o n o f t h r e e cc oxygen per liter,  g.  Bate o f oxygen consumption i s not s i g n i f i c a n t l y a f f e c t e d by i n c r e a s e d h y d r o s t a t i c p r e s s u r e c o r r e s ponding t o a depth o f about 400  ?•  m.  I n g e n e r a l , t h e data a r e c o n s i s t e n t w i t h McLaren^s  (1963)  t h e o r y o f energy u t i l i z a t i o n and v e r t i c a l m i g r a t i o n , a l t h o u g h temperature does not appear t o always be t h e most s i g n i f i c a n t  factor.  environmental f a e t o r s may of v e r t i c a l  distribution.  I n t e r a c t i o n and v a r i a t i o n o f e x p l a i n some o f the complexity  39 VI•  L i t e r a t u r e Cited  Anraku, M. 1964. Influence o f the Cape Cod Canal on the hydrography and on the copepods i n Buzzards Bay and Cape cod Bay, Massachusetts, I I , Respiration and feeding, Limnol. Ooeanog. 9[Z):195«?E06, Berner, A, 1962, Feeding and r e s p i r a t i o n i n the copepod Temora longicorals (Muller). J , mar, h i o l . Ass, U.K. 42:625-640, . "T n  Bishop, J,W, 1964, Zooplankton metabolism: oonstancy i n the natural h a b i t a t . Abstracts of the 27th Ann* Meeting o f the American Society o f Limnology and Oceanography, p, 4, Brodsky, K.A. 1950, Calanoida o f the f a r eastern and polar seas o f the U.S.S.E. T a b l . and ffaune R.R.S.S. No, 35, Brodsky, K.A. 1957, Copepods (Calanoida) and the zoogeographioal d i s t r i b u t i o n i n the northern part o f the P a c i f i c Ooean and neighbouring waters* Zool* Inst* Akad. Sauk, U.S.S.R, 222 pp* Cenover, H.J. 1956. Oceanography o f Long Island Sound. VI* Biology o f A o a r t i a olausl and A. tonsa. B u l l . Bingham Ooeanogr. C o l l . 15:156-233. Gonover, R.J. 1959* Regional and seasonal v a r i a t i o n i n the respiratory rate o f marine copepods* Limnol. Qceanog* 4;259-268* Gushing* D.H. 1951* The v e r t i c a l migration of planktonic orustaeea* B i o l . Rev. 26(2): 158-192* Enright* J.T. 1965* The search f o r rhythm!city i n b i o l o g i c a l time«*series. J . Theoret. B i o l * 8:426-468* Plemister, L . J . and Plemister* S.C. 1951* Chloride i o n regulation and oxygen consumption i n the crab Ooypode albicans (BosgJ. B i o l * B u l l , 101:259-273. Preund, J.E., P.E. Livermore and I . M i l l e r . I960. Experimental S t a t i s t i c s . Prentice-Hall* Inc. Englewood C l i f f s , N.J. v i i i f 132 pp. Gilmartin* M.  1962. Annual c y c l i c changes i n the physical  oceanography o f a B r i t i s h Columbia f j o r d . J . P i s h . Res. Bd. Canada. 19(5):921-974. Grainger* J.N.R. 1958. F i r s t stages i n the adaptation o f poikilotherms t o temperature change. In Physiological Adaptation (Ed.) C L . Prosser, 1958* pp* 79-91.  40 Gross, W.J. 1 9 5 7 . An analysis of response ;bo osmotic stress i n selected decapod crustaoea. B i o l . B u l l . 1 1 2 : 4 3 - 6 2 . Halorow, K. 1 9 6 3 . Acclimation to temperature i n the marine copepod, Oalanus finmarchious (Gunner). Limnol. Oceanog. 8(l):l-8.  ~  ,  "  —  J s  -  Hansen, V.K. 1 9 5 1 . On the diurnal migration of zooplankton i n r e l a t i o n to the discontinuity l a y e r . J . Cons. i n t . 8  Expl8r.  Mer.  !  IV:  231-241.  n  Harder, W. 1 9 5 7 . Verhalten von Organism gegenuber der Sprungsohichten. Anee Biol.' 3 3 : 2 2 7 - 2 3 9 . " H a r r i s , J.E. 1 9 6 3 . The role of endogenous rhythms i n v e r t i c a l migration. J.' mar, b'iol. Ass. U.K. 4^': 1 5 3 - 1 6 6 . Kinne, 0 . 1 9 6 4 . The effects of temperature and s a l i n i t y on marine and brackish water animals. I I . S a l i n i t y and temperature s a l i n i t y combinations. Oceanog. Mar. B i o l . Ann.'  Hey.  :  2J:281*239.  Lance, J. 1 9 6 2 . E f f e c t s of water of reduced s a l i n i t y on the v e r t i c a l migration of zooplankton. J . ajar.' hjLol. Ass. U.K.  ,42:131-154.  Lance, J. 1 9 6 5 . Respiration and osmotic behaviour of Acartia tons a i n diluted sea water. Oomp. . B'ioohem. P k y s i o l . 1 4 : T55-T65. Lewis, A.G. 1 9 5 9 . The v e r t i c a l d i s t r i b u t i o n of some inshore copepods i n r e l a t i o n to experimentally produced conditions of l i g h t and temperature. B u l l . Mar. S c i . Gulf and Oarib. 9(1):69~78.  ~~  L o f t s , B. 1 9 5 6 . The effects of s a l i n i t y changes on the respiratory rate of the prawn Palaemonetes varians (Leach),. J. exp. B i o l . 3 3 : 7 3 0 - 7 3 6 . Marshall, S.M., A.G. M e h o l l s and A.P. Orr. 1 9 3 5 . On the biology of Calanus finmarchious. Part VI. Oxygen consumpt i o n i n r e l a t i o n to environmental conditions. J . mar, b i o l . Ass. U.K. 2 0 ( l ) : l - 2 7 . Marshall* S.M. and A.P. Orr. 1 9 5 8 . On the biology of Oalanus finmarchious. X. Seasonal changes i n oxygen consumption. J. mar. b i o l . Ass. U.K. 3 7 : 4 5 9 - 4 7 2 . McLaren, I.A. 1 9 6 3 . E f f e c t s of temperature on growth of zooplankton and the adaptive value of v e r t i c a l migration. J. F i s h . Res. Bd. Panada. 2 0 ( 3 ) : 6 8 5 - 7 2 7 . Moore, H.B. 1 9 5 5 . Variations In temperature and l i g h t response within a plankton population. B i o l . B u l l . 1 0 8 ( 2 ) : 1 7 5 - 1 8 1 .  41 Moore, H.B. and E.G. Corwin. 1956. The e f f e c t s o f t e m p e r a t u r e , i l l u m i n a t i o n a n d p r e s s u r e on t h e v e r t i c a l d i s t r i b u t i o n of z o o p l a n k t o n . B u l l . M a r . S c i . G u l f and O a r i h . 6 ( 4 ) : 2 7 3 ^ 2 8 7 . Moore, H.B. and D.L. 0 ' B e r r y . 1 9 5 7 . P l a n k t o n o f t h e F l o r i d a current. IV. Factors i n f l u e n c i n g the v e r t i c a l distribut i o n o f s o m e common c o p e p o d s . B u l l . M a r . S c i . G u l f a n d P a r i p. J7(4): 2 9 7 - 3 1 5 . " Mori,  T . 1 9 3 7 . The P e l a g i c Copepods W a t e r s o f J a p a n . 150 p p .  from the  Neighbouring  Napora, T.A. 1964. The e f f e c t o f h y d r o s t a t i c p r e s s u r e on t h e p r a w n , S y s t e l l a s p i s d e M l i s . Symp. on E x p . M a r . E o o l . Ooca. P u b l . Narragansett Mar. L a b . No. 2. pp. 9 2 - 9 4 . Pamatmat, M.M. 1965. A c o n t i n u o u s - f l o w apparatus f o r measuring metabolism o f b e n t h i c communities. L i m n o l . Ooeanog. 1 0 ( 3 ) : 486-489. — P o t t s , W.T.W. brackish  1 9 5 4 . The e n e r g e t i c s o f and f r e s h water a n i m a l s .  osmotic regulation in J . exp. B i o l . 31:618-630.  P o t t s , W.T.W. and P a r r y , G. 1 9 6 4 . Osmotic and I o n i c i n A n i m a l s . Pergamon P r e s s , London. 423 p p . P r o s s e r , C L . and F.A. Brown, J r . 1 9 6 1 . Comparative P h y s i o l o g y . W.B. Saunders C o . , P h i l a d e l p h i a , i x Raymont, J . E . G . 1 9 6 3 . P l a n k t o n and P r o d u c t i v i t y P e r g a m o n P r e s s , New Y o r k , v i i i / 6 6 0 p p . Raymont, J . E . G . planktonic  Regulation Animal / 688 p p .  i n the  Oceans.  a n d D . T . G a u l d . 1 9 5 1 . T h e r e s p i r a t i o n o f some copepods. £ . mar, b i o l . A s s . U.K. 29:681-693.  Ringelberg, J . 1961. A physiological s t a n d i n g ov v e r t i c a l m i g r a t i o n . s e r . G. 6 4 : 4 8 9 - 5 0 0 .  approach to Proc. Acad.  an underS c i . Amst.  R i n g e l b e r g , J . 1 9 6 4 . The p o s i t i v e l y p h o t o t a c t i c r e a c t i o n o f D a p h n i a magna S t r a u s : A c o n t r i b u t i o n t o t h e understanding o f d i u r n a l v e r t i c a l m i g r a t i o n . N e t h . J . Sea R e s . 2,(3): 319-406. S c h l i e p e r , C. 1929. Uber d i e Einwirkung n i e d e r e r S a l z k o n z e n t r a t i o n e n auf marine Organismen. Z. v e r g l . P h y s i o l . 9:478-514. S n e d e c o r , G.W. 1 9 5 6 . S t a t i s t i c a l Methods. C o l l e g e P r e s s , Ames, Iowa.  5th e d . ,  Iowa  State  Swed, F . S . and C. E i s e n h a r t . 1 9 4 3 . T a b l e s f o r t e s t i n g randomness o f grouping i n a sequence o f a l t e r n a t i v e s . Ann. Math. Stat. 14:66-87.  42  T a n a k a , 0 . 1 9 5 6 , The p e l a g i c copepods o f t h e I z u r e g i o n , m i d * d i e J a p a n . S y s t e m a t i c A c c o u n t I. F a m i l i e s . G a l a n i d a e a n d E u c a l a n i d a e . P u b l . Seato mar, h i o l . Lab. j>(2):251-272. Teal,  J . M . and Z . H a l c r o w . 1 9 6 2 . A technique for of r e s p i r a t i o n of s i n g l e copepods at s e a . £ . Explor. Mer. 27(2):125-130.  measurement Cons, int.  T u l l y , J . P . and A . J . Dodimead. 1957. P r o p e r t i e s of the water i n the S t r a i t o f G e o r g i a , B r i t i s h Columbia and i n f l u e n c i n g f a c t o r s . J . F i s h . Res. B d . Canada. 1 4 ( 3 ) : 2 4 1 319. U m b r e i t , W.W., E . H . B u r r i s and Techniques. Burgess P u b l . 338 ,pp.  J.F. Co.,  S t a u f f e r . 1957. Manometrio Minneapolis, Minn, i i i f  W a l d i o h u k , M. 1 9 5 7 . P h y s i c a l oceanography o f t h e S t r a i t of Georgia, B r i t i s h Columbia. J . F i s h . R e s . B d . Canada. 14(3):321-486. Zeiss, F.B. 1963. E f f e c t s o f p o p u l a t i o n d e n s i t i e s on z o o p l a n k t o n r e s p i r a t i o n r a t e s . L i m n o l . Ooeqnog. 8:110-115. Z e n k e v i t o h , L. 1963. B i o l o g y of the Seas o f t h e U . S . S . R . ( t r a n s ) . George A l l e n & Unwin L t d . , London. 955 p p .  43  A p p e n d i x I* B e p l i o a t e measurements o f r a t e o f oxygen c o n sumption (ul 0 used / copepod / hr) w i t h r e s p e c t t o crowding. D a t a w e r e . c o l l e c t e d d u r i n g J u n e 1 9 6 4 a t FHL 2  Crowding (copepods /  ml)  1,0 .  3,3  4.0  4.3  5.0  1.06 0.28 2.10 0.29 0.89 0*88 0*65 0*65 0.78 0*60 2.45 1.26 2.03 0.43 1.94 1.72 0.60  0.81 1.21 1.41 1.21 1.21 1.41 1.01 1.62 1.62 1.62 1.82 1.41 1.62 1.62 1.62 1.62 1.62 2.22 0.81 1.82 1.82 2.42 2.02 1.82  0.45 1.08 1.05 0.91 1.17 1.11 1.16 1.22 1.25 0.50 1.19 0.87 1.17 1,00 1.00 0.88 1.18 1.43 0.18 1.00 1.06 1.24 1.13 0.77  0.78 1,37 1,37 1.17 1.17 1.56 0.39 1.76 0.98 0.39 1.17 1.17 1.17 0,98 0.78 1.17 0.98 0.59 0.00 0.98 0.78 0.59 1.17 0.39  1.09 1,00 0.92 1.05 0.58 0.60 0.49 0,60 0.43 0.90 0.70 0.71 1.23 0.28 0.94 1.07 0.19 0.75 0.25 1.63 0.37 0.89 0.33 0.51  *  Mean  1.24  1.15  1.00  0.95  0.70  S.E.  0.14  0.08  0.06  0.08  0.07  44 Appendix I I . - D i e l measurement o f rate o f oxygen consumption (ul 0 usea / copepod / h r ) . Mean values of r e p l i c a t e determinations are l i s t e d with standard error given below i n parenthesis. Data f o r oolumns A and B were c o l l e c t e d during June 1964 at FEEL and data f o r oolumns 0, D, and B were c o l lected during November 1965 at BBC. Data l i s t e d under columns A, B, e t c . correspond to the.curves designated by the same l e t t e r s i n Figures 3 and 4 o f the text. Curves shown i n F i g s . 3 and 4 A  B  C  D  3  3  0*40 (0.21) .0.40(0.10)  0.33 (0.12) .0*25(0.08)  -  -  0.40 (0.23) 0.32(0.04)  0.69 (0.14)  0.56 (0.17)  0.57 (0.21)  0.46 (0.01)  0.34 (0.03)  0*36 (0.03)  0.35 (0.02)  0.23 (0.04)  0.39 (0.13)  # of r e p l i c a t e s Gopepods / replicate  8-13  E  15  Determinations: . Time 10:00 pm 1:00 am 2:00 3:00 4:00 5:00 6:00 7:00 7:15 8:00 9:00 10:00 11:00 12:00  0«58 (0.13) 1.17. (0*13) 1.18(0.12) -1.02(0.10) 1.18 (0.08) 1.26(0.11) 0.98. (0.26) -  1.41 (0.18) 1.27. (0.15) 0,70 (0.25) 1*31 (0*15) 1.04 (0.14)  1.09 (0.16) l.oo: (0.94) 0.92 (0.31) 1.05 (0.02) .0.58. (0.04) -  0.60 (0.06) 0.49 (0.04) 0*60 (0.08) 0.43 (0.04) 0.90(0.02)  -  -  0.47 (0.10) 0.60. (0.11) -  -  •  0.53 (0.06) 0.33 (0.13)  0.62 (0.04) 1.88 (0.46) -  45 Appendix I I  (Cont'd.) Carves shown i n F i g s . 3 and 4 A  1:00 pm 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 1:00 am 2:00 3:00  1.26 (0.12) 1.12(0.15) .1.08(0.17) -1.09 (0.18) -1.23(0.11) 1.42(0.28) 0.27(0.15) 1.16 (0.19) 1.16 (0,19) .1.34(0.32) 1.31 (0.19) -1.10(0.27) .1.12. (0.29)  ' B  -•  0.70 (0.04) .0.71(0.03) 1.23 (0.05) 0.28(0.17) 0.94(0.14) 1.07 (0.05) 0.19(0.04) 0.75 (0.05) 0.25(0.06) 1.63(0.21) 0.37(0.06) 0.89(0.40) 0.33 (0.04) ,0.51. (0.16)  • - Cf4  E  3D  :i  0.49 (0.12) -  0.58 (0.13) -  0.75 (0.25)  1.17 (0.33)  0.63 (0.09)  1.70 (0.55)  0.45 (0.04)  0.71 (0.17)  0.81 (0.38)  -  •  •  0.46 (0.05)  0.78 (0.18)  0.88 (0.48)  -  -  0.43 (0.10) j  0.34 (0.15)  1.25 (0.50)  46  Appendix III. Comparison o f r a t e o f oxygen consumption (ol 0 u s e d . / copepod / hr) w i t h r e s p e c t t o l i g h t and d a r k at four temperatures. Standard errors are l i s t e d i n parentheses below the means. Copepods were t e s t e d a t a concentration of f i v e per three ml of sea water. T e s t s were r u n d u r i n g June 1965 at UBC. 2  Temperature ( G ) 0  Duration of t e s t (hrs)  Light  7.13  10  7.17  x  15  20  4.03  6.53  x  Dark  0.84 0.25  0.23 0.25  0.24 (0.01)  0.24 (0.02)  0.45 0.51 0.27  0.15 0.38 0.53  0.41 (0.10)  0.32 (0.12)  0.42 0.65 0.99  0.72 0.34  0.69 (0.17)  0.78 (0.06)  1.56 1.25 1.41  1.41 2.31  1.41 (0.10)  1.86 (0.42)  47  Appendix 17. Bate o f oxygen consumption (ul 0 used / copepod / hr) w i t h respect t o t e m p e r a t u r e . Standard errors are l i s t e d i n parentheses beside the values. Data pres e n t e d f o r 1964 a n d May 1 9 6 5 w e r e c o l l e c t e d a t F H L , w h e r e a s d a t a p r e s e n t e d f o r November 1965 were c o l l e c t e d a t UBC. In the table* X denotes u n c o r r e c t e d raw d a t a and X denotes data corrected for seasonal size variation. g  1  Temp. ( ° 0)  Date:  Duration of tests (hrs)  12.0 11.9 12.0 12.0  4 10 12*5 15 20 Date: 3 8 10 12 18  ul  used/cop./hr :  X  X  1  50 50 50 50  6-8 j 6-9J , 6-9; 7 - 8 j•  5 5 4 5  0.38 0.69 0.94 0.96  (0.04) (0.08) (0.07) (0.08)  0.35 0.63 0.86 0.90  (0.04) (0.07) (0.06) (0.07)  10 10 10 10  0.30 0.57 0.68 1.14  (0.02) (0.07) (0.04) (0.04)  0.28 0.52 0.63 1.05  (0.02) (0.07) (0.04) )0.04)  10 10 10 10 5  0.12 0.20 0.24 0.35 0.58  (0.01) (0.03) (0.04) (0.04) (0.07)  0.22 0.37 0.45 0.67 1.08  (0.03) (0.06) (0.07) (0.08) (0.13)  0.13 0.39 0.58 0.50 0.67  (0.02)  0.10 0.30 0.46 0.38 0.52  (0.01)  9-10/VI/64 12.0 11*5 12.0 12*0  2 10 15 20 Date:  # oopepods used/test; # of tests  4/VI/64  2 10 15 20 Date:  Test Vol. (ml)  19  50 50 50 50  9-10;; 1 1 - 1 5 ;; 9*11 ; 10-13;,  /V/65 36.9 36.6 35.5 37.1 15.3  35 35 35 35 35  5 ;• 3-5;, 1-5,> 2-5;; 5 ,i  35 35 10 35 35  5 5 5-8 5 5  ll/Xl/65 26.5 15.0 3.0 17.0 3.0  ; ; ;  6 1 2 9 ; 2  (0.06) (0.06) (0*05)  (0.02) (0.05) (0.04)  48  A p p e n d i x V. H a t e o f o x y g e n c o n s u m p t i o n ( o l Og u s e d / o o p e p o d / hr) with respect to s a l i n i t y . Standard errors are l i s t e d in-parentheses beside the values. Experiments reported for J u l y 1964 w e r e c o n d u c t e d i n 50 m l chambers a n d e x p e r i m e n t s r e p o r t e d f o r May 1 9 6 5 w e r e c o n d u c t e d i n 3 5 m l c h a m b e r s . The e x p e r i m e n t s w e r e c o n d u c t e d a t FHL a n d a l l t e s t s w e r e r u n a t 1 0 ° 0. In the t a b l e , X d e n o t e s u n c o r r e c t e d r a w d a t a a n d X* denotes data correoted f o r seasonal s i z e v a r i a t i o n .  Salinity (ppt)  Bate: 2© 25 30 35  Bate: 10 20 25 30 35 45  Duration of tests (hrs)  Test Yol. (ml)  # oopepods used/test; # of tests  ul — X  0„  used/oop./hr — — Z f  26/YII/64 13.5 12.8 12.5 12.3  50 50 50 50  4; 4; 6-10; 4;  3 3 10 3  £.02 0.78 0.76 0.76  (0.26) (0.09) (0.09) (0.18)  0.93 0.72 0.70 0.69  (0.24) (0.08) (0.08) (0.16)  0.56 0.22 0.23 0.24 0.32 0.13  (0.11) (0.01) (0.03) (0.05) (0.05) (0.02)  0.95 0.42 0.43 0.44 0.60 0.26  (0.18) (0.03) (0.05) (0.09) (0.09) (0.04)  18/Y/65 35 35 48 35 35 35  35 35 35 35 35 35  5-6; 4 5; 5 5; 5 4^-5; 5 3-5; 5 5; 4  49  Appendix VI, H a t e o f o x y g e n c o n s u m p t i o n ( u l Og u s e d / o o p e p o d / h r ) w i t h r e s p e c t t o oxygen c o n c e n t r a t i o n and t e m p e r a t u r e . Standard errors are l i s t e d i n parentheses beside the values. D a t a r e p o r t e d f o r M a y 1 9 6 5 w e r e c o l l e c t e d a t FHL a n d d a t a r e p o r t e d f o r November 1965 were c o l l e c t e d a t UBC, All tests were c o n d u c t e d i n 35 m l t e s t c h a m b e r s . In the t a b l e , 2 denotes u n c o r r e c t e d raw d a t a and X denotes data corrected for seasonal size variation, 1 1  Temp.(°C): 0 cone. (3o Og/l) P  Duration of tests (hrs)  # copepods used/test; # of tests  ul  0  ?  used /  X  cop, / .-•— X*  hr  Date:S4-26/Y/65 5: .  1,12 2.10 2.24 4.75 5.28 1 0 : 0*88 2.02 2.63 3.64 4.10 4.68 15: 1.87 2.53 3.16 4.78 Date: 3:  12:  18:  30 48 53 47 46 17 13 20 20 19 20 12 12 15 15  3 3 3 3 3 3 3 3 2 3 3 3 3 3 3  0.11 0.21 0.13 0.14 0.17 0.28 0.25 0.18 0.22 0.28 0.26 0.23 0.19 0.33 0.33  i i 2 ; 2 ; 2 • 2 ; 2 ; 2 ; 2 ; 2 ; 2 ; 4 ; 4 ; 4 ; 2  0.03 0.09 0.09 0.13 0.19 0.07 0.23 0.14 0.63 0.36 0.10 0.18 0.48 0.70  5; 4-5; 5; 5; 4-5; 5; 5; 5; 4-5; 5 ;, 5; 5 ;, 5 ;, 5 ;, 5 ;»  (0.04) (0.08) (0.01) (0.01) (0.04) (0.01) (0.04) (0.01) (0.01) (0.03) (0.02) (0.06) (0.06) (0.12) (0.09)  0.21 0.40 0.24 0.25 0.32 0.51 0.49 0.32 0.40 0.53 0.50 0.44 0.37 0.63 0.61  (0.08) (0.17) (0.02) (0.02) (0.07) (0.01) (0.10) (0.01) (0.01) (0.06) (0.05) (0.10) (0.10) (0.21) (0.13)  11-12/XI/65 0.80 2,17 2.67 3,60 5.85 0.85 1.15 2.00 3.43 5.85 1.00 1.17 2.50 6.00  26 26 27 27 26 15 15.5 17 17 17 10 12 12 14  4 4 4 4 4 4 4 4 4 4 4 2 2 4  ;  (0.02) (0.01) (0.01) (0.01) (0.02) (0.18) (0.03) (0.03) (0.10) (0.01) (0.04) (0.03)  0.03 0.08 0.08 0.12 0.17 0.07 0.21 0.13 0.58 0.33 0.09 0.17 0.44 0.64  (0.02) (0.01) (0.01) (0.02) (0.16) (0.03) (0.03) (0.09) (0.01) (0.04) (0.03)  50  A p p e n d i x VII. B a t e o f o x y g e n c o n s u m p t i o n ( u l 0r> u s e d / c o p e p o d / h r ) w i t h r e s p e c t t o h y d r o s t a t i c p r e s s u r e . ..Stanctard e r r o r s a r e l i s t e d i n parentheses b e s i d e t h e v a l u e s . A l l experiments were conducted d u r i n g lovember 1 9 6 5 at UBC. T e s t chambers were 10 m l . In the t a b l e , X denotes u n c o r r e c t e d raw d a t a and X denotes data corrected f o r seasonal s i z e v a r i a t i o n . 1  Pressure (atm)  Duration of tests (hrs)  Temperature:  # copepods used/test; # of t e s t s  ul  Og u s e d /  cop. X  /  hr  1  10° C  1.00  2.90  5,8;  2  0.58  (0.06)  0.46  (0.05)  10.35 13.80  1.40  5,9; 5,8;  2 2  0.41 0.55  (0.05) (0.01)  0.32 0.43  (0.05) (0.01)  27.60 31.00  9.30 1.70  1 2  0.40 0.28  (0.04)  39.70  3.25  8; 5,9; 5,8;  2  0.36  (0.11)  0.21 0.28  2 2 2  0.65 0.52 0.34  (0.03) (0.06) (0.11)  0.50 0.41 0.27  Temperature:  3.15  12  1.00  1.65  19.00  1.75  36.20  7. 30  0.31 (0.03) (0.09)  0 5,9; 9,11; 11;  (0.02) (0.05) (0.09)  

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