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Functional responses and feeding strategies of fresh-water filter-feeding zooplankton Buckingham, Sandra 1978

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c  FUNCTIONAL RESPONSES AND FEEDING STRATEGIES OF FRESH-WATER FILTER-FEEDING ZOOPLA K KTON by SANDRA LYNN BUCKINGHAM B . S c , Queen's U n i v e r s i t y , 1967 D.E.A., O n i v e r s i t e de M o n t p e l l i e r (France), 1969 Doct. de 3® C y c l e , U n i v e r s i t e de M o n t p e l l i e r , 1970  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY THE  in FACULTY OF GRADUATE STUDIES {Department c f Zoology)  we 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 ERITISE COLUMBIA J u l y , 1S78 Sandra Lynn Buckingham, 1S78  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 an a d v a n c e d d e g r e e a t the L i b r a r y I further for  shall  the U n i v e r s i t y  make i t  agree that  British  freely available for  permission for  Columbia,  I agree  r e f e r e n c e and  extensive copying of  this  thesis for  It  financial  i s understood that gain shall  written permission.  Department  nf  Zoology  The U n i v e r s i t y o f B r i t i s h 2075 W e s b r o o k P l a c e V a n c o u v e r , Canada V6T 1W5  Date  February  20,  Columbia  1979  not  for  that  study.  this  thesis  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 t h e Head o f my D e p a r t m e n t  by h i s r e p r e s e n t a t i v e s . of  of  the requirements  or  copying or p u b l i c a t i o n  be a l l o w e d w i t h o u t  my  ABSTRACT This study  examined t h e  concentration freshwater biomass  lakes model  zooplankton -  of in  British  was  used  at  harvest  food  efficiently  rates:  p e r i o d s o f time 2P-labelled  should  ability  types  obtain  of f o o d , y e a s t  Functional  responses  were compared (asymptote rate  food  by an a b i l i t y t o  was ; used  h a d been a d d e d .  and a c c l i m a t i o n t i m e .  maximum f i l t e r i n g  maximal  densities. to  t o graze  t o which  r e p r e s e n t i n g 8 s p e c i e s from  near  be o f two d i s t i n c t  allowed  responses,  and  plankton  small  measure  f o r short  amounts  of  A preliminary series  f o rpossible effects of container  kind  feeding rate  simple  several  that  to  were  in  seston  hypothesis  low f o o d  on n a t u r a l s e s t o n  yeast c e l l s  time,  -maximum  the  technique  zooplankton  technigue,  grazing  A  develop  i n very  tracer  of experiments checked rinsing  to  to  zooplankton  h i g h f o o d d e n s i t i e s and t h e o t h e r  radioactive  feeding  an  response  Columbia.  feeding strategies  intake  3  filter-feeding  one c h a r a c t e r i z e d by  A  functional  dosage l e v e l , A total  size,  length of  of 5 3 f u n c t i o n a l  6 l a k e s , were  measured.  by e x a m i n i n g two p a r a m e t e r s of the functional  (slope o f the  response),  functional  response  the o r i g i n ) . Some  of  functional  the  species  response,  occasionally  type.  studied  range  a  very  sigmoid  but i n g e n e r a l most o f t h e r e s p o n s e s  of t h e D i s c o r Michaelis-Henten had  exhibited a  similar  Most of  of  the  functional  were  species response  iii  parameters,  and e s s e n t i a l l y  Maximum  filtering  8°  2 0 ° C.  to  at  maximum  r a t e s were i n d e p e n d e n t  Maximum f e e d i n g  f u n c t i o n s of temperature, and  identical  "cold" species  vita  rates-  temperature  r a t e s , on t h e o t h e r  dividing  highest  of  filtering  from  hand, were  t h e z o o p l a n k t o n i n t o "Harm"  m e a s u r e d maximum  feeding  rates  20° and 8° C r e s p e c t i v e l y . The  similarity  o f f u n c t i o n a l response  r a n g e o f s p e c i e s and l a k e s s t u d i e d fact  be  underlying  a  small  number  of  parameters over the  indicates that  general  feeding  the observed complexity o f agnatic  there  may i n  strategies  ecosystems.,  TABLE OF CONTENTS  L i s t ' O f T a b l e s - . ....... ...... . . . . . . . . . ... . . . . . . . . . . . • * • • . List  Of F i g u r e s  .-. v i  .........................................vii  A c k n o w l e d g e me n t s .......... . ... . . . . . . . . . . . . . . . . . . . . . . • - . . . x i 1 .Introduction' .  .  m  .  .  m  .  .  " i t .General- ... . Response  1.3 I m p o r t a n c e  Of F u n c t i o n a l  2 T h e o r e t i c a l Background  2.2 S t a b i l i t y  >  Of F i l t e r  Of O b j e c t i v e s  2.1 F u n c t i o n a l  .  .  .  .  . :  . 7 . ' .  1-2 F u n c t i o n a l  1.4 O u t l i n e  .  v  .  .  .  .  .'.'I*-  •  <  .  t  Feeding Zooplankton 4  Responses  ...............6  ............................ 8  .....,•......;,•>.......•-••v:«W«.»>-Vi.r,.1.Q  Response  Types  Of F u n c t i o n a l  2.3 E v o l u t i o n a r y  .  ........................10  Responses  Adaptation  ................20  Of F u n c t i o n a l  R e s p o n s e s -.26  2. 3. 1 . . I n t r o d u c t i o n . - .- . ... . . . . . . . . . . . . . . . . . . • . - . . . .26 :  2.3.2 Z o o p l a n k t o n P o p u l a t i o n s  Limited  By Food  2.3.3  Limited  By P r e d a t i o n  Zooplankton Populations  .....28 31  2. 3.4 . P r e d i c t i o n s .........-. .-.. .. .......................33 2. 3. 5 D i s c u s s i o n  «.r..•...-..''»....,;..>;.<••'..•,•••.••«-35  2.3.6 E v i d e n c e From The L i t e r a t u r e 2.4 . C l a s s x f i e a t i o n . . 3 Ex p e r i menta1 D e s i g n  . . . ...  .  -  -.38 .v • •. ....  43  ....•.....•••.-.-....-.-.----...>.-.46  3.1 C h o i c e Of T e c h n i q u e ..............................51 3.2 D e s c r i p t i o n O f Methods Used  ......................57  V  3- 3 E f f e c t s 4  Of E x p e r i m e n t a l  ---,,,,---.,---62  Results 4- 1 T e s t s  Of E x p e r i m e n t a l  4.2  .,,64  Conditions  4-1-1  S i z e Of G r a z i n g  4.1.2  Zooplankton Rinsing  4.1.3  K i n d O f Food  4.1.4  Radioactive  least  ...........................75  4. 1.5  L e n g t h Of G r a z i n g  T i m e ..........,.......-<. , . 7 8  4.1.6  Acclimation  •Concentration  5  Conditions  ...67  .,w..v-:..---«..>-...-i/-,-y,,v«-*>v.»-*$*•  To  Experimental;  ,,,,,88  Results  - . . . . . . . . , - , , . i . : . >  ;  , • • , , , . • , , ^ , . : > 1 2 6  5.1  Consistency  126  5.2  T y p e s Of F u n c t i o n a l R e s p o n s e  5.3  C o n s t a n c y Of F u n c t i o n a l Responses  With Other Data  5.3.1  Effect  5.3.2  Acclimation  Of T e m p e r a t u r e  Obtained  To Food C o n c e n t r a t i o n  F u n c t i o n a l Response A d a p t a t i o n  5.5  General  6 Bibliography  ............132 , v - - . 1 3 3  .......................133  5.4  Remarks  Food  . . . . . . . .. „>.,,, ,•, . . . . . . . . . . . . . . . . . 79 ••  F u n c t i o n a l Response  Discussion  .........,....,,.-..64  Chambers  ,.139 ,,,,,,,,,141  ..................................143  .,'.,,...,,.....,,:.,;,.-..,-...,,:,-,>,-.--.-146  {  vi  L I S T OF  I.  II-  Characteristics  Parameter equations  III.  of  the  estimates (1),  (7)  those  lakes  obtained and  Comparison of f i l t e r i n g study v i t h  TABLES  (8)  to  used  by  this  fitting  t h e measured  r a t e s measured  measured by J . F .  in  Haney  in  this  (1973) ..,-130  vii  L I S T OF F1GJJRES  1- C l a s s e s  o f f u n c t i o n a l response  2- T y p e s o f f u n c t i o n a l r e s p o n s e  generated  hypothesized  by H o l l i n g * s  for  filter-  f e e d i n g zooplankton.^.„. . . . . . . . . . . . . . . . . . . . . . . . . . 3 5 3. F u n c t i o n a l  responses  proposed  by  Goodman  {1973) t o e x p l a i n s e a s o n a l s u c c e s s i o n o f  4. Hap s h o v i n g  6. E x p e r i m e n t a l  l a k e s from  which  zooplankton  two d i f f e r e n t  8. R e s u l t s ensure  of  filtering  kinds of container.  using  a  adequate r i n s i n g  taken  of  ................66 "post" feed t o  of radioactive  particles  D a p h n i a -.-.rosea f i l t e r i n g  10. C o m p a r i s o n o f D a p h n i a p u l e x  from  ........................68  with s e s t o n and w i t h C h l o r e l l a .  with  were  r a t e s measured  nonradioactive  f e e d i n g appendages. 9. C o m p a r i s o n  phytoplankton  c o n f i g u r a t i o n . , ........................,58  7. A c o m p a r i s o n o f D a p h n i a r o s e a in  et a l .  r a t e s measured  .....................70  filtering  rates  measured  s e s t o n and w i t h C h l o r e l l a .  11. C o m p a r i s o n  of  Ceriodaphnia  72 sp.  filtering  measured w i t h s e s t o n and w i t h C h l o r e l l a . 12. C o m p a r i s o n o f  Holopedium  gibberurn  rates  ,,,,,.,.73  filtering  rates  viii  measured 13.  with s e s t o n  Filtering different  14.  rates  and of  amounts o f  Filtering different  with  C h i o r e l l a.  Daphnia  rosea  . . . . . . . . . . . . 74 measured  r a d i o a c t i v e yeast.  r a t e s o f Holopedium  76  q i b b e r u m measured  amounts of r a d i o a c t i v e y e a s t .  15.  Radioactivity  16.  Effect  of  various  of  animals  as  holding zooplankton lengths  with  of  time  with  .............77  a f u n c t i o n of  feeding  i n the  laboratory  for  between  collection  and  measurement o f f e e d i n g r a t e s . / .......................81 17.  Effect food  18.  of h o l d i n g Holopedium  regimes before  Effect  of  different  19-  Effect  Results  on  from  length  21.  of  time  "Standard" species. ingested  a  given the  weight)/hour.  free Food  rates  figure  plotted  concentration  dry  are  under  different  has  in  food  .,.....,.85 t o show  of  with  to that  measured units  how  varies  to a c c l i m a t e  f u n c t i o n a l : responses  Feeding (ash  to  animal  .83  measuring f u n c t i o n a l  measured f i l t e r i n g r a t e s .  previous  f e e d i n g r a t e at  oreqonensis  before  acclimation  concentrations 20.  P i a i> torn us  regimes  of  different  measuring f u n c t i o n a l responses.  holding food  qibberum under  for ug.  food  weight)/ug. zooplankton  concentrations  8  are expressed  (dry as  ug/ral a s h f r e e d r y w e i g h t . 22.  I n i t i a l slope feeding  23.  slope  M  I n i t i a l slope  " a " o f f u n c t i o n a l r e s p o n s e v s . maximum .................112  " a " o f f u n c t i o n a l response  f e e d i n g r a t e "V" f o r D i a p t o m u s k e n a i . 25.  Initial  slope  feeding rate 26.  Initial  M  27.  Initial feeding  l  Feeding  29.  Feeding  M  f o r Ceriodaphnia  f o r Holopedlum  n  slope n  sp.  v s . maximum .......v...115  " a " o f f u n c t i o n a l r e s p o n s e v s . maximum n  f o r Diaptomus t y r e l l i  and  Diaptomus  p a r a m e t e r s o f s p e c i e s t a k e n f r o m OBC Pond and  parameters  ofspecies  Lake, and Katherine  t a k e n f r o m Deer  31.  T e m p e r a t u r e v a r i a t i o n o f maximum  parameters o f s p e c i e s t a k e n from E u n i c e  Daphnia r o s e a Temperature  and Daphnia pulex. variation  feeding  Lake,  rates f o r  ..,.,.,.....,......,120  o f maximum f e e d i n g r a t e s f o r  Holopedium qibberum and Diaptomus k e n a i . Temperature  Lake,  L a k e . / . . . . . . . . . . . . . . . . . . . . 118  Feeding  33.  v s . maximum  ............... 114  qibberum.  30.  32.  ...............113  " a " o f f u n c t i o n a l response  rate V  28.  Placid  n  v s . maximum  " a " o f f u n c t i o n a l response  V  slope  feeding rate  v s . maximum  .................111  f o r Daphnia r o s e a .  r a t e "7" f o r D a p h n i a p u l e x .  feeding 24.  " a " o f f u n c t i o n a l response  r a t e "V  Initial  ....,,....,....,.,......,.89  v a r i a t i o n o f maximum  feeding  ............121 rates f o r  X  D i a ptomus t y r e l l i . 34. T e m p e r a t u r e  35. T e m p e r a t u r e  36. Temperature  -  variation  variation  variation  Diaptomus kenai  • • ,. ,.,•.'..„>  o f maximum f i l t e r i n g  o f maximum f i l t e r i n g  and Holopedium  t h i s study with  rates f o r  rates  o f maximum f i l t e r i n g  37. Comparison o f Daphnia r o s e a in  . . ... • .. • . . . . . . . .122  gibberura.  filtering  for  rates f o r  ............125  rates  measured  t h o s e measured b y Burns a n d a i g l e r  38. F i l t e r i n g r a t e s o f D a p h n i a r o s e a a f u n c t i o n o f body l e n g t h .  a n d Daphnia  pulex a s  ..........................129  xi  ACKNOWLEDGEMENTS  Many p e o p l e assistance I  helped  me i n t h i s  endeavour;  without  their  I would n o t h a v e been a b l e t o c a r r y o u t t h e s t u d y .  am i n d e b t e d t o my s u p e r v i s o r , D r .  encouragement,  advice H.E.  and  Hoiling,  financial  Dr.  Dr.  Parsons  provided v a l u a b l e h e l p and c r i t i c i s m Ho t h a n k s  T.G.  forhis  support.  Bossert,  during t h e study.  Neill,  C.S.  Northcote,  and  Dr.  H.  Dr.  T.  at various  times  would be t o o much f o r P r o f .  H.Q.  Yorgue. My e x p e r i m e n t a l without  the  myriad  of  superb  chemical  supervising the  Begina  help  demanding  replenishing  teaching  work would h a v e been  me  tasks  Pierre  -  maintaining  of  weighing  the  seston  more  limited  who l o o k e d a f t e r a yeast  cultures,  plankton  samples,  concentrator,  t o use the s c i n t i l l a t i o n  Clarotto collected  study.  Paul S t a r r ,  solutions,  building  how  of  much  counter.  most o f t h e z o o p l a n k t o n  and  Paul and  used  i n the  Kleiber contributed his expertise i n handling  radioisotopes. Pinally,  I t h a n k my h u s b a n d , C a r l  anyone, h a s h e l p e d start me  me d u r i n g t h i s  i t , r e v i v e d my e n t h u s i a s m  solve  cajoled,  insurmountable and t h r e a t e n e d  study.  who, more  He e n c o u r a g e d  when t h i n g s went wrong,  problems,  me i n t o  Halters,  and f i n a l l y ,  finishing  my  me  than to  helped  he p l e a d e d ,  thesis.  1  1 IHT80DDCTI0B  1- 1 G e n e r a l  In  recent years  understand  and  ecosystems.  predict  Host  emphasizing  extensive  eutrophication  complexities  i n t e r a c t i o n s and r e s p o n s e s  to  researchers,  more i n t e r e s t e d  whole,  coupled  extensive  use  have  been  of  of  separate  models i n an a t t e m p t  component  changes.  i n t h e behaviour of  Other  o f systems a s a processes  with  not only t o develop a  general understanding o f aquatic food chains but a l s o t o practical  predictions  systems.  Such  reasonably observed and  models  simple  as  community feeding  nature.  Of c e n t r a l i m p o r t a n c e  transfer,  functions  models rate  consistent  necessarily  in  assume  and  specific  that  to  these  p r e d i c t i o n s a r e the f u n c t i o n a l responses  rates of biological uptake,  must  eutrophication  make  some  systematic s t r u c t u r e u n d e r l i e s the apparent  complexity.  their  about  to  reductionist,  separate  environmental  analysis  made  processes i n aquatic  work h a s been d e s c r i p t i v e a n d  the  have  efforts  are  of  Yet without  resource  acutely  functions, reliable  such  but  as  feeding  and  availability.  sensitive  to  guantification  of  these  o f such  describing nutrient Plankton  parameters  i t i s very d i f f i c u l t  estimates  models  of  to obtain  parameters  in  relationships f o r  2  a range  of resource  s i t u a t i o n s and  c o n d i t i o n s , the  have no  ingested  per  function general  biomass  level  zooplankton makeup o f  of  ingested  representation  by  aquatic  aost The  by  food.  ecosystem  (1949) t o  of  a  feeding food  This  i s on  than  current  most  is  not concerned i t  is  feeding  rate  as  part  -  herbivore  of  Functional attack  generally an  that  a  a more  work  on  with  the  precisely  where f e e d i n g  the  this  i s required  density  response  The  the  rate  expression  changes  dependent  in  has  since  an  organism's  refer to predator  plant's  the  response  f u n c t i o n of changes i n  may  r a t e , or a  in  coined  r e f e r r e d to  r a t e of a predator  instantaneous  grazing  as  models.  i n prey d e n s i t y .  mean more  density  rate,  biomass  available.  i t  per  the time  However  describe  predation.  change  used t o  of  unit  of zooplankton  change i n i n s t a n t a n e o u s to  f u n c t i o n a l response  t e r m f u n c t i o n a l r e s p o n s e a p p e a r s t o h a v e been  Solomon  nature  zooplankton  because  general  new  specifically,  investigation  feeding,  the  -  biomass of food  of  the  with  zooplankton  of the  to  p r e d i c t i v e power.  T h i s t h e s i s i s concerned filter-feeding  models cannot apply  r a t e : of  been  the  attack  nutrient  uptake. Hoiling  (1965) has  suggested  of  f u n c t i o n a l responses i n t o four  His  component model of  him  to  identify  the  a qualitative classification  predator-prey biological  distinct  types  (Figure  interaction also conditions  implicit  1 ).  allowed i n each  3  PREY Figure  1.  DENSITY  C l a s s e s of f u n c t i o n a l response generated by H o l l i n g ' s p r e d a t i o n model.  4  qualitative prey  are  constant  type o f response. , & type I response located  until  by  touch.  satiation  The  occurs.  detects  decreases  continuously as i t s l e v e l  i n addition*  by  the  with  IV  alternative  decreased  response  densities)  the  type  to f i l t e r  when  of  filtration organic in  and  to  and i t s s e a r c h  rate  increases.  I I I response  prey  defense  concerned  ingestion  in  order.  response and  discuss  Feeding  Zooplankton  with  zooplankton the  by  be  filtered  clear  of  as food  zooplankton particulate  rate of a zooplankter, water  why  known  method  the  I  generally  attention..  refers to  The f i l t e r i n g  prey  Then  merit  employed  A  rate.  functional  of zooplankton  (at high  o f w a t e r by s e t o s e a p p e n d a g e s t o remove  matter.  remains  a r e present,, a n d i f l e a r n i n g  u n i t s o f v o l u m e / t i m e , i s t h e volume o f  have  the  zooplankton,  " f l i t e r - f e e d e r s " . , This label collection  response,  satiation  i n attack  feeding  i s  II  a sigmoid, or type  1.2 F u n c t i o n a l B e s p o n s e Of F i l t e r  study  search  a t t a c k r a t e a t low prey d e n s i t i e s .  occurs  f u n c t i o n a l responses  This  of  p o i n t a few d e f i n i t i o n s a r e  describe  attributed  distance,  prey  causes a decrease  At t h i s will  a  p r e d a t o r o c c u r s , then  results, type  at  when  of  In a type  predator  If,  prey  rate  results  measured  which  of i t s food p a r t i c l e s  would  i n a given  5  time  t o provide the quantity  during at  t h e same t i m e .  the  matter  to t h i s  from  given  the  over  I t i s measured  saturating 1965; to  Fuglister,  is  qualitative 1975).  form  for  response  Probably  i s the Hichaelis-Henten  ? =  ¥" x k  less  o f the  1961; HcHahon,  Fuglister most  Stewart,  applied  used  and  purposes, I I response  expression  of  this  equation:  (D  • x  quantity  filtering  t o have some k i n d o f  •-  where F = r a t e o f f o o d  than  appendages^  models), a type  t h e most w i d e l y  volume  i s some d i s a g r e e m e n t a s  (Huilin,  However,  the  feeding  (e.g. S i g l e r ,  f o r use i n a q u a t i c e c o s y s t e m  used.  water,  water.  P a r s o n s e t a l . , 1967), b u t t h e r e  the exact  (i.e.  response  animal  i s 100% e f f i c i e n t  as t h e product  f e e d e r s a r e g e n e r a l l y assumed functional  the  i n g e s t e d by an a n i m a l i n  r a t e a n d t h e f o o d c o n c e n t r a t i o n o f the Filter  by  i s actually  the  r a t e i s the quantity o f food time.  eaten  definition  volume o f water t h a t p a s s e s  Feeding a  according  food  S i n c e no z o o p l a n k t e r  removing p a r t i c u l a t e  "filtered"  of  uptake, i n q u a n t i t y of food  o f zooplankton  V  maximum a s y m p t o t i c  x  density  k  Hichaelis-Henten  per u n i t  per u n i t  time  value o f F  o f food  food  constant  f o r food  uptake, i . e . the  d e n s i t y a t w h i c h F = 1/2 V.  This  6  parameter r e f l e c t s zooplankton food.  the r e l a t i v e  ability  of  to gather sparsely d i s t r i b u t e d  I t i s a l s o known a s t h e " h a l f - s a t u r a t i o n  constant".  1.3 I m p o r t a n c e O f F u n c t i o n a l R e s p o n s e s  Form  and  interest  in  Functional as  almost  response  playing  animal  magnitude  an  any  important  form  functional  study  of  of  zooplankton  role  in  available  i s  a q u a t i c f o o d web Lam a n d F r o s t ,  (1965)  response  confers  noted different As f a r  frequently  stability as  filter-  for  an  that  to concentration of  understanding  (Mayzaud and P o u l e t , 1978; Lehman,  responses  believed  of i t s two p a r a m e t e r s  h a v e been a t t r i b u t e d  population  each  i t h a s been r e c o g n i z e d  of the zooplankton  important  that  to follow  of the  1976;  Michaelis-Menten  ( e q u a t i o n 1) have g e n e r a l l y b e e n s t u d i e d b y  the behaviour  as  dynamics.  1976) ^  Functional dynamics  of  the " n a t u r a l c o n t r o l " o f  Boiling  are concerned,  the f u n c t i o n a l response food  are  population  p r o p e r t i e s on p o p u l a t i o n s and e c o s y s t e m s . feeding  responses  was r e c o g n i z e d a s e a r l y a s 1949 by Solomon  populations.  qualitative  of  characteristics,  7 and k.  almost  These  mystical  examining parameters  significance  and t h e y have been t h e o b j e c t  7  of  much h y p o t h e s i z i n g ( M a c l s a a c a n d D u g d a l e ,  al.,  1969; Goodman In  spite  plankton  of  systems  p r e d i c t i o n s about  of  the  f e e d i n g and  aquatic  values  e t al.,1973;Dugdale, wide  nutrient  and the  available and  data  (1) t o e x p r e s s in  studies  sensitivity to  the  them  application  in  Furthermore,  the e x p e r i m e n t a l  which  data  almost  feeding  systematic comparative  of these The  of forms  useless  and m o d e l l i n g  for  studies.  t e c h n i q u e s and c o n d i t i o n s  were p r o d u c e d  of  lack  rates.  a wide v a r i e t y completely  of  numerical  v a l u e s and r a n g e s  f o r zooplankton  et  1975).  V a n d k, t h e r e i s a c o n s p i c u o u s  a r e p u b l i s h e d i n such  u n i t s as t o render  these  rates  community  e x p e r i m e n t a l d a t a on t h e n a t u r a l particularly  of equation  acknowledged  plankton  Eppley  1967; C r o w l e y ,  uptake  the  o f t h e parameters  parameters,  or  use  1969;  under  were by no means s t a n d a r d i z e d ,  e v e n c o m p a r a b l e i n t e r m s o f t h e i r e f f e c t s on what was b e i n g  measured. gleaned  Much o f t h e f e e d i n g p a r a m e t e r i n f o r m a t i o n indirectly  researchers  have  from  explicitly  functional relationships, Part  of  the  difficulties  miscellaneous experiments  problem,  o f such  sought  especially  to  of course, l i e s  an i n v e s t i g a t i o n .  be  b e c a u s e few  measure  under n a t u r a l  must  feeding  conditions.  with t h e e x p e r i m e n t a l  8  1 . 4 O u t l i n e Of O b j e c t i v e s  T h i s study of  the  concerned  functional  zooplankton.  1...... To  was  The  responses  objectives  to  those  of  functional  of f i e l d  see  The  the s h a p e s and several  zooplankton  these  stable^  l o o k f o r any  or  evidence  response  functional  response  try,  whether  responses  they  show  in  from  are  transient  food  supply,  o f an e v o l u t i o n a r y a d a p t a t i o n o f  to food  supply.  parameter  F o r e x a m p l e , do  values  the grazers i n t o  characteristic  w o u l d e n a b l e one  of t h e i r  t o determine  reflect  oligotrophic  w i t h i n f o r m a t i o n o b t a i n e d from  above, to c l a s s i f y groups  feeding  etc.  functional  To  magnitudes  were o b t a i n e d  functional  d i s t r i b u t i o n among e u t r o p h i c and  4.  possible  filter  s e n s i t i v e t o hunger, changes  temperature,  To  f liter-feeding  l a k e s i n the Vancouver r e g i o n .  whether  behaviour  of  aspects  follows:  situations,  species.  intrinsically  3.  freshwater  were a s  responses  several different  To  of  different  t r y t o m e a s u r e , under c o n d i t i o n s a s c l o s e a s  zooplankton  2.  with s e v e r a l  a  species  lakes?  objectives small  the  number  1 - 3 of  feeding behaviour.  This  f u n c t i o n a l ; responses  from  9  biological  and  geographical c h a r a c t e r i s t i c s rather  f r o m c o s t l y e x p e r i m e n t s f o r each water  Following with  each  this brief  one  of the d i f f e r e n t  outline  i n greater d e t a i l ,  than  body.  of objectives,  I  beginning with a  forms o f f u n c t i o n a l response.  will  deal  discussion  10  2 THEORETICAL BACKGROUND  2.1  Functional  R e s p o n s e Ty pes  In  order  t o make use  between  food  grazing  zooplankton,  concentration  relationship of s p e c i f i c planktonic  provide  and  the  must of  be  on  (see  able  behind  to  the  a  e a c h o f them  paragraphs d i s c n s s  used  to  express  Fuglister  given may  be  quite  some o f t h e  the  on  Stewart,  of  and often  data,  the  different.  The  models t h a t h a v e b e e n  f u n c t i o n a l responses of f i l t e r  group  A number  models w i l l  set  by the  been u s e d i n work  prey d e n s i t y . , B o i l i n g ' s c l a s s i f i c a t i o n been  to  ingestion  quantifiable function.  Mullin,  fits  relationship  of  Although s e v e r a l of these good  to describe  the  rate  f u n c t i o n s have t r a d i t i o n a l l y  equally  following  some k i n d  1975) *  assumptions  used  by  one  grazers  Fuglister,  of i n f o r m a t i o n  (see  models a c c o r d i n g  feeders  Figure  1)  to has  to the q u a l i t a t i v e  c h a r a c t e r i s t i c s of t h e i r f u n c t i o n a l form. Type I i s a r e c t i l i n e a r rises  linearly  maximum a t t a c k the  with rate.  assumptions  searching density  rate  that  m o d e l , i n which  increasing This kind the  of  search  i s independent*  o f p r e y o r g a n i s m s , and  up  prey  rate  of  concentration  attack to  response curve a r i s e s f o r p r e y i s random, t h a t to  that the  a  threshold, time spent  of  some from the the  separately  11  on  prey  handling  filter-feeding particles  i s negligible.  zooplankton  a constant  in  water past  concentration gathering  direct of  the  (filtering)  concept o f handling ingestion  digestive for  the feeding and  a  proportion water-, and  If  Rigler  much o f t h e f e e d i n g  Daphnia  authors  through  predation,  also  fitted  In  is similar contains on  food the  saturation  proposed on  such  results  data  a  model of h i s  i t has  obtained  been  f o r various  Burns  and  Rigler  to  a  constant  (1967)  Rosea w i t h  plateau.  a  Hoi l i n g  a n a l y s i s o f t h e components and mechanisms o f believed  and  Poulet  some q u i t e of  food  of  At some  a  rectilinear  model  have r e c e n t l y p r o p o s e d  different  digestive  would  best  zooplankton.  i n many r e s p e c t s t o t h e r e c t i l i n e a r  evidence  which  in  functions  f e e d i n g r a t e s o f D^  d e s c r i b e g r a z i n g by h e r b i v o r o u s Mayzaud  increases  Subsequently,  1967).  form t h a t r o s e non l i n e a r l y (1965),  ingestion  mean  (McMahoo and R i g l e r , 1963, 1965; McMahon,  Burns and B i g l e r , the  constant  were s i m u l t a n e o u s ,  based  used t o d e s c r i b e  though,  the  (1961) f i r s t  zooplankton,  A  by t h e c a p a b i l i t i e s o f t h e  D a p h n i a magna.  1965;  to  processing  experiments with  of  of  to  collecting  a p p e n d a g e s would  time would: n o t a p p l y -  filter-feeding  species  by t o u c h ,  rate  would be l i m i t e d  system.  apply  from a f e e d i n g c u r r e n t .  r a t e of search,  increased  point,  d e t e c t i n g prey  that are seived  rate of f i l t e r i n g  S u c h a model c o u l d  assumptions. system  a model w h i c h  one, but  which  The model i s b a s e d  acclimation  (Mayzaud and  12  Poulet,  1978; Mayzaud and  Conover,  Poulet  measured  rates  feeding  1976)-  of  five  m a r i n e c o p e p o d s and f o u n d  that ingestion  enzyme  linearly  food  activity  supply  natural  seasonal  of  saturation  of  and  digestive  fluctuating  potential  of  over  the  digestive in  Mayzaud*s  enzymes  - 20 h o u r s ,  food and  o c c u r r i n g over for  affinity  varied  long  and  model  of  a  yielded and t h e to  chemical  herbivorous  f o r v a r i a t i o n s of food  time p e r i o d s  v a r i a t i o n s over  to  according  concentration Poulet*s  with  matter..  the zooplankton  18  feeding i s , accordingly, l i n e a r  saturating  particulate  Furthermore, t h e apparent  changes  concentration and  concentrations  curves.  composition. copepod  concentrations  term e x p e r i m e n t s , e x p o s i n g  food  capability seasonal  species of n e r i t i c rate  with  and  when t h e e x p e r i m e n t s were done o v e r a s e a s o n  However s h o r t range  varied  Hayzaud  (weeks t o y e a r )  a time s m a l l e r than  that  needed f o r a c c l i m a t i o n . In a type with  I I response,  a decreasing  response neither  can  s l o p e , towards  arise  nor  simultaneous  T h i s w o u l d be t h e c a s e food  interrupted  Until  dependent  with  maximum  asymptotically, value.  Such  h a n d l i n g a prey on  time spent  prey  item i s  density*  searching  a  nor  (filtering)»  f o r example, i f i n g e s t i o n o f a b o l u s o f  one  mechanisms, o r i f t h e feeding.  a  i f the time spent  negligible,  completely  feeding rate rises  of  the  zooplankter  recently,  food i s  gathering/processing capable  nonlinear  of  functions  selective used  to  13  represent t h i s almost  kind  of  exclusively  Henten t y p e . been u s e d . equation  zooplankton  of  the I v l e v  (Ivlev,  Holling»s d i s c e q u a t i o n I t i s formally identical  but  statement  feeding  was  response  1961)  (Holling, to  the  or  in  the  same  format  as  the  Hichaelis-  1959)  has  also  Hichaelis-Henton  d e r i v e d d i f f e r e n t l y - ; I t warrants  here  were  an  explicit  Hichaelis-Henten  model:  ( 1 / Th) 1/(a where  x  Th)  • x  F = r a t e of food food  per  Th = t i m e  q u a n t i t y of zooplankton  spent  handling  eating) x = prey  i n g e s t i o n , measured i n q u a n t i t y o f  each  per  unit  (pursuing, capturing,  time and  prey  density  a = rate of successful search If handling a linear  Comparing  time  Th  i s negligible  t h i s equation  simplifies  to  response:  F =  a x  (2)  with  (3)  (1)  we  see  14  V = 1 / Th  k =  1 /  (5)  (a Th)  (6)  a k  Although  derived to represent f i s h  the I v l e v curve  h a s o f t e n been used  filter-feeding.  Parsons  f e e d i n g on s m a l l  a s a model f o r z o o p l a n k t o n  , LeBrasseur,  and F u l t o n  d a t a on f e e d i n g r a t e s o f m a r i n e c o p e p o d s w i t h an modified Their  t o i n c l u d e the concept  data  suggested  s t o p s a t some f o o d (1970)  measured  that  density  ingestion  and  marine copepods as a f u n c t i o n and  fitted  Ivlev curve concept into  the used  has  communities..  models However,  of  such  experiments  which  count  a  over  LeBrasseur,  Parsons  a certain  plankton  evidence  by  and  than  zero,  continuous  results et  curve  with  a l .  matter  HcAllister  grazing rates of concentration,  t h e same m o d i f i e d  (1967).  The  refuge  a p p e a l b e c a u s e when i t i s i n c o r p o r a t e d i t imparts  stability  to  plankton  i t i s c u r i o u s that the only reported  threshold measure  fairly  Ivlev  of p a r t i c u l a t e  of phytoplankton  experimental  {1967} f i t  of a refuge f o r phytoplankton.  greater  nocturnal  prey,  behaviour  i s  f e e d i n g r a t e by d i f f e r e n t i a l  long  Fulton,  feeding  incubation  1967; H c A l l i s t e r ,  period 1970).  from cell  (Parsons, I t may be  15  that such  t h r e s h o l d behaviour  Hullin, examined function models two  Fuglister  Frost's  Statistical  to  analysis  between t h e  whether  or not  on  the  rectilinear models had  a  data  positive  curves.,  x-axis  modelling  zooplankton  type  work  curve  significance (1975)  used  grazing  by  mainly to  of  on  to  that;  existence  adopted.  the  two  The  nonlinear  of  (1971) the  They c h o s e  Steele  d i d not  Green Hew  used  a of  i t  an  over  biological  (1974)  and  Walsh  to describe  (1975) f o u n d Zealand  report the  the  dynamics  the d i s c equation  f o r feeding r a t e s of the but  Bass  chains i n  e a s i e r to a t t a c h  parameters.  lucasi  found  t o show t h e  describe  phytoplankton.  modifications  copepod Calamoecia  latter  differences in  marine food  herbivorous zooplankton.  response  the  intercept.  also  but  a  different  x-axis  model  origin  b e c a u s e i t was  the  three  They  Walsh and  expression  g r a z i n g on  have  intercepts.  u p w e l l i n g ecosystem,  Hichaelis-Henten  of  significant  model i n t e r c e p t e d t h e  their  to f i t h i s  no  the  (1975)  Hichaelis-Henten,  were c o n s i d e r e d  on  technique.  i n g e s t i o n by c o p e p o d s a s  positive  showed  of the  Fuglister  terms  I v l e v , and  fitted  of a r e f u g e depended  II  data  allow  variance  Ivlev  and  of f o o d c o n c e n t r a t i o n i n  modified  Peruvian  Stewart  (1972)  - rectilinear,  In  i s an a r t i f a c t  a  type  freshwater  f u n c t i o n used  data.  Crowley for deriving  (1973)  used  Holling* s disc equation  a model i n which  feeding rate i s linear  as a  basis  below  a  16  certain  limiting  c o n c e n t r a t i o n , and  asymptotically nonlinear c  above.  T h i s model assumes h a n d l i n g t i m e  densities,  and  that  time  i s not reduced  the  limiting  below t h e l i m i t i n g  b y e a t i n g and  concentration  density  a t which a f u l l  point,  digestibility  handling  time  A type  are that  and  g r e a t e r than  The  vertebrate obtained  that  predators.  -  the  thought the  prey  above  this  prey  impose  response He  a  behind  rise  to  an  upper  Boiling's derivation  alternative  on  a  of i t  prey  that  prey a r e p r e s e n t .  Type  Hassell  experimental  c l a i m s a sigmoid  searching efficiency  e t a l . (1977)  evidence  of  prey  response  density  declines.  i s likely  below  which  of  have  sigmoid  f o r a number o f i n v e r t e b r a t e p r e d a t o r s  threshold  a  food processing. sigmoid  However  assembled  parasitoids.  for  represented  of  prey  have g e n e r a l l y b e e n c o n s i d e r e d c h a r a c t e r i s t i c  and  functional  is  a  Crowley  predators can learn to concentrate  responses  there  z e r o on  low  density, search  maintained  ingestion  assumptions  becomes numerous, and III  probably  has  prey  digestion.  gut i s j u s t  I I I response  asymptote.  i s zero at  and  whenever predator  T h i s t h r e s h o l d would be  higher  non-preferred prey s p e c i e s . The  existence  feeding zooplankton mechanism  in  populations. response  may  the  of  sigmoid  response  has l o n g been d i s c u s s e d a s dynamics  of  I t i s a l s o tempting reflect  curves f o r  an a t t e m p t  a  filter-  stabilizing  phytoplankton-rzooplankton  to speculate t h a t a  on t h e p a r t o f t h e  sigmoid  zooplankton  17  to  reduce  during  the  energy  costs  c o n d i t i o n s where r e t u r n s a r e n o t  normal s e a r c h Lehman feeding  (1976) h a s and  the  zooplankton  food  net  in  influenced feeder,  within  zooplankter relation  to  maintain  relation  between  i s to  for  u n t i l an  a filter  known  that the  of  energy  has  disc  fact,  an  the  filtering  one The  r a t e s i s one  where  gut  increasing concentration  Then t h e  filtering  concentration. with  i s sigmoid  sigmoid  empirical  f o r low  type  by H e a l  analogy  addition  filter  i n g e s t i o n r a t e i s r e a c h e d a t which the  agrees  is identical  the  is  food  packed.  been p u b l i s h e d  through  for  and  rate  intake.  food  r a t e s decrease The  with  to the of  a  The  allosteric  equation  of  expressing equation  was  enzyme k i n e t i c s ,  Hichaelis-Henten third  food  conditions.  behaviour with a s i n g l e  (1977).  with  corresponding  models a t h i g h  & f u n c t i o n a l response r e l a t i o n s h i p capable both  feeding  particulate  feeding  gut  that  of  i n c r e a s e s i n food  d e n s i t i e s , but  by  of  optimize  optimal  particles  curve  in  filter-  various external constraints,  r a t e i n c r e a s e s with  ingestion  food  feeding behaviour  assumes  filtering  further  for  for invertebrate  suspension  model  that,  completely  sigmoid  to p r e d i c t the  t h e amount o f f o o d  and  predicted  a  concentration  food  The  by  the  sufficient  r a t e of energy gained  a  composition.  g o a l of  proposed  It i s derived  maximizes  i n searching  efforts.  rate  feeding.  is  involved  parameter.  expression According  derived and  in  except to  this  18  equation,  response  parameters related  -  behaviour  maximal  to handling  can  feeding  time,  rate,  capture  third  parameter  clear,  b u t whose v a l u e d e t e r m i n e s  sigmoid  whose  exact  be  explained  by  an* a f f i n i t y  efficiencies,  biological  three constant  e t c . , and  a  a n a l o g u e i s n o t made  whether the  curve  will  be  or not.  Seal's equation  i s expressed  as  n F =  v x  —  ,  (7)  n G • x where F = f e e d i n g r a t e , a s p r e v i o u s l y d e f i n e d V = maximum f e e d i n g x = food  rate  density  n = number o f p r e y e n c o u n t e r s before that  must h a v e  i t i s maximally e f f i c i e n t a t h a n d l i n g  type  G = an a f f i n i t y  the predator  of prey  constant, equal t o the food  which f e e d i n g r a t e y i s h a l f  density a t  i t s maximum  value  F o r n = 1, (7) becomes t h e d i s c eg n a t i o n . , Type IV r e s p o n s e s , densities, zooplankton. food  are  not  with lowered often  attack r a t e s at high  attributed  to  I t may be p o s s i b l e h o w e v e r , t h a t  concentrations  from a mechanism s u c h  a  decrease  filter-feeding at  very  i n feeding rate could  as p h y s i c a l clogging  of  prey  the  high result  filtering  19  appendages, to  prevent The  or,  i n cladocerans,  clogging  Fujii  (Gliwicz,  equation  a decrease  i n carapace  1977).  (Fujii, Holling,  and Hace i n prep.) i s  a general formulation o f the predation process, from four o f the basic types cases.  of feeding curves  I t was d e r i v e d f r o m  the search  rate a  constant.  function  Biologically;  number  attack  of  prey  as  special  of  this  prey  density  instead  assumption  can  facilitation  by  be  of  a  made  to  learning  as  c o n t a c t s i n c r e a s e s , o r an i n h i b i t i o n o f  r a t e f o r high prey  The  emerge  which a l l  H o l l i n g ' s d i s c e q u a t i o n b y making  d e s c r i b e , f o r example, p r e d a t o r the  width  densities.  F u j i i f u n c t i o n h a s t h e form 7 x T  =  ~ -ex k e  where V = maximum x = food  ,  (8)  • x  feeding rate  density  k >. a n a l o g o u s t o a f f i n i t y  constant;  inversely  p r o p o r t i o n a l t o t h e s l o p e dF/dx n e a r x=Q c = a constant  To show i t s r e l a t i o n expressed  as  to t h e disc equation,  (8)  can  also  be  20  1 =  F  1  a* where a ( x ) =  (9)  #  Th •  a  x  exp(cx)  exp(ex) i s s e a r c h r a t e as a f u n c t i o n  1  of  prey  density  If  c  =  0,  (?)  reduces  to the d i s c  equation.  p o s i t i v e v a l u e s o f c t h e c u r v e i s s i g m o i d , and a dome-shaped c u r v e  2.2  Stability In  is  Of  may  vary  responses environment  treated  or  as  the  The  concentrations,  changing. light  regimes  not r e f l e c t  the  animal  intrinsically  fixed  seen  a l l  response  but generally functional responses  to  a  uniform  scale.  by z o o p l a n k t o n  Temperature  F u n c t i o n a l responses  c o n d i t o n s may  c  o f an  magnitude o f t h e  stable  environment  response  less  t h a t c h a n g e s o n l y on a g r o s s  constantly  hours.  more  somewhat w i t h t e m p e r a t u r e ,  However, and  a  functional  of that animal.  are  f o r negative  F u n c t i o n a l Responses  as  characteristic  certain  results.  modelling s t u d i e s the  treated  Por  vary  i s varied  conditions, on a  time  measured u n d e r s t a b l e feeding behaviour  of  food  scale  of  laboratory zooplankton  21  in  lakes.  is  sensitive  lake than  Certainly,  i f t h e foris o f t h e f u n c t i o n a l  t o r a t e o f change o f f o o d c o n c e n t r a t i o n ,  ecosystem  would have v e r y d i f f e r e n t  would be p r e d i c t e d  response.  using  Although  considered  to  be  a  laboratory  responses  be  single  to  misleading  i f  sensitive  t o various environmental cues.  few  s t u d i e s have r e c e n t l y  of the changeable Hall  functional  measurements  are  conditions,  the  responses  are  F o r example,  transient  changes over s e v e r a l hours o r days a f t e r A  constant  functional  i n t o t h e l a b o r a t o r y may show  capture i n the f i e l d .  appeared  on v a r i o u s a s p e c t s  Daphnia  vertical  migration.  found  exhibited  bimodal  They  p u l e x and  that  they  during rates  descent  a t dawn.  o f about  estimated  half that  to  levels.  be  a t dark  separated  t h e peak f i l t e r i n g about  associated  Ambient s e s t o n  population  activity.  ascent  in  Filtering were i n d e e p  and d e c r e a s e d  Peak v a l u e s o f 5—10 t i m e s t h e d a y t i m e  between dusk a n d dawn. seem  during  occurred twice during t h e night,  decrease Hall  increased  experiments  the Daphnia  patterns of f i l t e r i n g  and  D, g a l e a t a  r a t e s were l o w e s t d u r i n g t h e d a y when z o o p l a n k t o n water;  Haney  series of i n s i t u  at v a r i o u s depths, f o l l o w i n g  animals  physiological  nature of f u n c t i o n a l responses,  (1975) d i d s e v e r a l 24 h o u r  a  properties  controlled  may  then  stability  feeding  results  brought  response  85%  rates.  midnight  Haney  of daily f i l t e r i n g  Changes i n f e e d i n g with  by a  activity  occurred d i d not  changes i n temperature  concentrations  were  and  slightly  or food lower  22  during  the  period  of  filtering  rate  increase,  sufficiently  t o have c a u s e d s u c h a l a r g e and  filtering.  Ho  observed  for  pronounced migrating  die!  not  abrupt change  filtering  Diaptomus  but  rate  pallidus  pattern  and  in was  Diaptomus  oreqonensis. In Daphnia  a  more c o n t r o l l e d s e t o f l a b o r a t o r y e x p e r i m e n t s  p u l e x . and  constant*  decreases  in  at  filtering  rate  period. in  filtering held  than  higher was  Starkweather  several  t h e low  rate.  feeding zooplankton  diel  in  the  variation  feeding/filtering i n c l u d e any  °C)  and  the  peaked  and light  midway i n  a l s o found  evidence t h a t such  f o r Daphnia  i n continuous darkness. caused  The  which But  are thus obviously  were  several  perhaps  o f some  sensitive even t o t h e  the diel  t h e f l u c t u a t i o n s t o dampen  F u n c t i o n a l responses  2-3  elevated  but  out  filter-  to  diurnal  point  where  become e n d o g e n o u s .  These o b s e r v a t i o n s c a l l interpretations  dark  maintained  environment;  has  rates  increases  of  (18  held  r a t e h a v e an e n d o g e n o u s component.  days  daytime  with  onset  rate fluctuations persisted  for  changes  the  temperature filtering  light,  temperature  not  filtering  and  observed  in  following  days o f c o n t i n u o u s l i g h t to  levels  (1975)  dark  abruptly  respectively,  changes  food  Starkweather  times higher  dark  with  with  one  might  rate  experiments  into tend  q u e s t i o n some o f the to  measurements. on d i e l  make  from  This  variation.  study  Instead,  initial  "standard" did I  not tried  23  to  minimize  any  consistently in  such  effects  same  as  following  day.  fluorescent to  generally  tested  each  took  of  a  dark  similar  of  the  of the length  light-dark out  8  p.m.,  the  by  the  under  dim  of time necessary  the a c t u a l r a d i o a c t i v e  diel  just  patterns,  i n that  24  variation  done  kept  feeding  before  the  T h u s , a s l o n g as a l l z o o p l a n k t e r s  were c o m p a r a b l e  patterns of d i e l  lake  because  cycle.  16:8  carried  were  rates  were  the animals, or a t l e a s t  experiments  and  with a  generally  p l a c e between 7 and  interval  account  of  experiment,  exhibited  experiments time  The  light,  prepare  onset  collection  were  feeding  Zooplankton  incubators  Feeding experiments day  measuring  a t t h e same t i m e o f day.  temperature-controlled  cycle.  by  hour  individual  t h e y were done i n t h e same cycle.  s h o u l d be  before extrapolating  the  Of c o u r s e ,  measured  and  possible  taken  into  t h e s e f e e d i n g r a t e s i n models o f  ecosystemsThere  responses  is are  evidence also  to  affected  suggest  that  the  by t e m p e r a t u r e  and  functional by c h a n g e s i n  food regime.  S e v e r a l i n v e s t i g a t o r s have r e p o r t e d peak  for  filtering  maximum  around  20-25 °C  1967;  Mcflahon,  filtering  r a t e s o f s e v e r a l s p e c i e s of Daphnia  ( B u r n s , 1969;  rates  1965). of  temperature,  and  at  peak f i l t e r i n g  12 PC  had  Hall,  However  Daphnia  Kibby  values  1964;  Burns  Schindler  magna  to  (1971) f o u n d t h a t r a t e s around  be  Higler,  (1968) f o u n d unaffected  Daphnia 12  6  °C  at  the by  rosea reared (Burns  and  24  Bigler D.  (1967) had  Rosea  at  observed highestmaximum  20  °C)-  dependence o f f e e d i n g  Information  rates f o r the  filtering  i s scarce  other  on  rates f o r  temperature  zooplankton  studied  here. fis  part of t h i s study  frequent  intervals  temperatures water to  from  during  measured f u n c t i o n a l r e s p o n s e s  the  sere kept the which the  I  s p r i n g and  same a s  animals  summers  the  o b t a i n f u n c t i o n a l responses over a range  but  since  I  temperature, species  I was  no  control  over  the  T h i s allowed of  the  of  me  temperatures,  changes  in  lake  unable t o get complete r e s u l t s f o r a l l  the  studied.  Until  recently,  p r i o r food been  had  Experimental  temperatures  were c o l l e c t e d .  at  investigations into possible effects  c o n d i t i o n s on  confined  animals before the  resulting  be  unaffected  HacHahon and amount o f  question  measuring t h e i r rates. by  Bigler  food  zooplankton  to t h e  zooplankton  Byther the  gut  when b o t h were e x p o s e d  to  However  food  unaffected filtering  limiting by  prior  r a t e s had  of  food  the other  any  already  and  effect  on  rate  to gut.  that  the  that  hour than p r e v i o u s l y f e d  non-limiting  food  concentrations,  starvation.  Hullin  starved animals,  concentrations. D.  magna  (1963)- s h o v e d  r a t e s of s t a r v e d C a l a n n s hvperboreus  the  i n the  hand, f o u n d  effect,  have  starving  (1954) o b s e r v e d f e e d i n g  d i d have an  f e d more i n one  in  whether o r n o t  feeding  amount  (1965) on  i n the  of  grazing experiments  of  seemed that  decreased  the for  25  many h o u r s a f t e r t h e It  now  Conover, affected the  start  appears 1976)  not  feeding. .  (Mayzaud and  that  o n l y by  Poulet,  zooplankton the l e v e l  1978;  change  of  hypothesized  of food  variability  and  time  concentration  the  zooplankton  i n the  water  various  lengths The  zooplankton  increasing experimental  how length food  of  in of  under  kind  The  before  d i f f e r e n t food The  first  refreshed  lake  measuring  their  regimes  last  effects before  experiment  f u n c t i o n a l r e s p o n s e s changed  concentrations.  of  collected  experiment examined  given  2.1.  of whether l a b o r a t o r y  regularly  r e s p o n s e s . ••  time  rate  mechanism  groups of f r e s h l y  time  second  measured  the  this  measurements.  holding  measuring t h e i r f u n c t i o n a l investigated  question  laboratory  f u n c t i o n a l responses.  investigate  feeding in  The  be  which  been o u t l i n e d i n s e c t i o n  to  related  affects  consisted  holding  has  and  to  a l s o by  concentration.  experiments  experiment  for  food  for this effect  I d i d three  holding  that  Mayzaud  f u n c t i o n a l r e s p o n s e s may  a n i m a l s have p r e v i o u s l y been e x p o s e d , but  of  of  of  for  acclimation  with to  26  2.3 E v o l u t i o n a r y a d a p t a t i o n Of F u n c t i o n a l B e s p o n s e s  2. 3.1 I n t r o d u c t i o n The  third  major q u e s t i o n which t h i s study  addressed  whether t r a i t s e v o l v e d by f r e s h w a t e r z o o p l a n k t o n different  environmental  r a t e parameters from  lakes  dominating  of the animals. differing  at specific  rate characteristics? •feeding functional unit  time  This  This third of  adapt  to  are reflected i n feeding  F o r example,  do  zooplankton  productivity,  or  zooplankton  display  very d i f f e r e n t  feeding  (By f e e d i n g r a t e c h a r a c t e r i s t i c s I mean  response*,  o r amount o f f o o d  ingested  pec  of t o t a l a v a i l a b l e food concentration.  i s not e x p l i c i t l y  or composition  model  in  seasons,  as a f u n c t i o n  study  conditions  to  was  concerned  with s i z e  distribution  of food.) q u e s t i o n was  zooplankton  approached  production.  by  using  a  simple  I t includes the f o l l o w i n g  assumptions: a) B i o m a s s v a l u e i s used  a s an i n d e x  to  the  success  of  any  species. b) B i o m a s s and  change i s determined  o n l y by r e s o u r c e  availability  predation.  c) P r e d a t o r s o r c o n s u m e r s a t a perceive  differences  given  among  trophic  types  of  level food  do  organisms  available. e)  F u n c t i o n a l responses  follow  Hichaelis-Henten  not  kinetics.  27  These assumptions l e a d t o t h e f o l l o w i n g phytoplankton  dz -~ = dt  where  and z o o p l a n k t o n  (Vz) (P) (Az) (z) - — — (kz) • P  z =  s i m p l e model  for  biomass dynamics :  -  (Hz) (z) —  (z) - f(Z,C) (Z)  (10)  b i o m a s s o f one s p e c i e s o f f i l t e r - f e e d i n g zooplankton  Az = a s s i m i l a t i o n  efficiency  Vz = maximum g r a z i n g r a t e kz = h a l f  (per unit  zooplankton  s a t u r a t i o n constant of zooplankton  biomass)  functional  response P = total  phytoplankton  Mz = z o o p l a n k t o n  or seston concentration  m e t a b o l i c 'rate  f (Z,C) = p r e d a t i o n r a t e , (C) a n d t o t a l  a function biomass  of c a r n i v o r e biomass  (Z) o f f i l t e r - f e e d i n g  zooplankton  dp — = dt  (VP) (H) (Ap) (p)  (Hp) (p) (kp) • N  (p) g(P,Z) (P)  (11)  where p - b i o m a s s o f one s p e c i e s o f p h y t o p l a n k t o n Ap = a s s i m i l a t i o n  efficiency  Vp = maximum r a t e o f n u t r i e n t kp = h a l f  uptake  s a t u r a t i o n constant of phytoplankton response  functional  28  N = total  available nutrient concentration  Hp = p h y t o p l a n k t o n  respiration  rate  g(P,Z) = g r a z i n g r a t e , a f u n c t i o n zooplankton  biomass  (Z) and t o t a l  What do t h e s e e q u a t i o n s s a y a b o u t we  might e x p e c t  s t r u c t u r e and n u t r i e n t assimilation  level;  efficiencies,  response  the kind of food  under d i f f e r e n t in  plankton  the  parameters  communities?  competing  will  uptake  c o n d i t i o n s of t r o p h i c  metabolic r a t e s , and  t o p r e d a t i o n a r e s i m i l a r among functional  phytoplankton  (P)  biomass  curves  of herbivorous  If  vulnerability species,  determine  a  then  species*  fitness-  2.3.2  Zooplankton  P o p u l a t i o n s L i m i t e d By Food  Consider f i r s t is  limited  This  will  predator (e.g. species  where z o o p l a n k t o n  by t h e amount o f probably  present. Stewart will  equilibrium  the case  the  according &  be  be  food  Levin, the  one  case to  1973), which  population  (phytoplankton) i f t h e r e i s no simple  can  available. significant  competition  the successful maintain  size  theory  zooplankton a  positive  p o p u l a t i o n a t the s m a l l e s t standing stock of food.  29  In  o t h e r words t h e s u c c e s s f u l s p e c i e s i s a b l e t o i n c r e a s e i t s  population level Now  u n t i l i t reduces  too  low  to  i f carnivores  equation  (10)  whichever food  t h e f o o d s u p p l y t o an  enable are  the  equilibrium  o t h e r consumer s p e c i e s t o  absent  from  equilibrium  the  system,  standing  ( i . e . phytoplankton)  persist-  then  stock,  from  Peg,  species survives i s  for given  by  Peg  From strategy  =  the p r e c e d i n g s h o u l d be  phytoplankton -  (kz) (Mz)/(Az) .— ) (Vz) - (Mz)/(&z)  one  the  which  persistent  leads,  this  physiological  which  equation  attributes  depend  minimizes  on  of  free  is  equation  solely  zooplankton  independently  strategy, to the smallest positive  the value of  not  paragraph,  the  t h u s i t i s t h e one  does  (12)  a  of  value of  (12). function  Peq  Bote t h a t of  the  the s u c c e s s f u l zOoplankter. nutrient  level  or  It  primary  productivity. Since eliminated  V  and  from  peq  The  parameter  =  w  k  are not  equation  (12)  independent by  1  (Vz) ( H z ) / ( A z )  a  (Vz)  substitution  —— -  (Hz)/(Az)  a " , i n addition  variables,  k can  of equation  )  to representing search  be  (6):  (13)  rate,  is  30  also  equal to the slope  origin  of the f u n c t i o n a l  ( o r w h e r e v e r P << k) .  t o t h e maximum f i l t e r i n g with n  a  w  a given  Therefore  rate  slope.  phytoplankton Halters this  rate  Note  also  the  equivalent  For  animals  V, P e g w i l l be m i n i m i z e d i f  p r o d u c t i v i t y as  that  ( p e r s . comm.) h a s examined  equilibrium  (equation  12).  the equilibrium  cycle  a r i s e s ; t o any z o o p l a a k t e r ,  a seasonal  point  environment.  nutrient  rich  the  Shen n u t r i e n t  world  In  sigmoid  model  the  catastrophic  of  abundance  associated  regulatory  effect  with  and  should  o f t h e two f e e d i n g  However, an a p p r o p r i a t e possibility  Vp,  or  input  unstable  this  2.3.4.  have  ftp,  of kp.  the s t a b i l i t y p r o p e r t i e s o f  a  environment, the e q u i l i b r i u m  zooplankton  high  independent  i s very a  limit  look  t h i s c y c l e i s induced, i t  p o s s i b l e t o have c o e x i s t e n c e below i n s e c t i o n  is  by  becomes  8hen  described  Peg  measured  large,  if  i ti s also  f o r zooplankton.  maximum f e e d i n g  near  i s maximized - i . e . i f t h e f u n c t i o n a l response has a  initial  be  response  highly  strategies productive  responses.  s i t u a t i o n would jumps  occasional  could  may be s t a b i l i z e d  functional  forthis  like  in  phytoplankton  escapes  o f the zooplankton f u n c t i o n a l  involve  from  response.  the  31  2-3- 3 Z o o p l a n k t o n  Populations  limited  population  food,  the s u c c e s s f u l zooplankter  than  when  maintains  the  levels  By. P r e d a t i o n  are limited  should  feeding  herbivore standing predation  of  a  less  stock)-  prey  pressure  Thus,  which  predator  productive  predation  be t h e one  from  will  should  sustain drive  s e v e r a l prey  populations  (Crowley,  i n t h e presence  the  which  (although  equilibrium the  other  I t i s n o t uncommon  with  eguation  strategy  determine  This  to extinction.  single  strategy  parameters  pressure,  zooplankters  rather  h i g h e s t p r o d u c t i o n r a t e a t i t s own e q u i l i b r i u m  population s i z e , independent o f c a r n i v o r e carnivore  by p r e d a t i o n  in  highest  competing situations  species t o f i n d the  disappearing  under  the  1975)., (10), the  of  successful zooplankter  carnivores  should  be  that  for  which  <Vz) (P) r  =  (Az)  (Hz) (kz)  is is  maximized. determined  successful the system. resource a)  Hote t h a t i n t h i s c a s e , not only  (14).  • (P)  by  the preferred strategy  physiological  attributes  z o o p l a n k t e r , b u t a l s o by t h e p r i m a r y Eguation  (14) c a n be s i m p l i f i e d  ( i . e . food i s very  abundant)  then  the  production i n  f o r extremes  availability:  i f P>>k  of  of  32  r =  b)  If P«k  ( i . e . food  r  By  (Az) (Vz) -  =  (16)  (Hz)  Holling*s (16)  then  relation  between  V  and  k  becomes  (17)  (Hz)  the f u n c t i o n a l response over  a range of  only  assumption t h a t changes i n f e e d i n g s t r a t e g y response t o  zooplankton for  scarce)  low  concentrations. The  the  i s very  (Az) (a) (P) -  where a = s l o p e o f food  of  6), equation  r =  (13)  (Az) (Vz) ( P ) / k -  substitution  (equation  (Hz)  have o t h e r  reducing  populations However,  predation truly  the  equilibrium  p r e d a t i o n i s an  oversimplification/  means, s u c h a s a c h a n g e i n pressure.  limited  by  represent  body  T h i s means t h a t predation  arguments o f t h i s s e c t i o n  p o p u l a t i o n which i s i n f a c t  may  should  predation  size,  zooplankton  be be  since  uncommon.  valid  for  limited.  an  33  2. 3. ft P r e d i c t i o n s The  model  predictions equilibrium a)  discussed  about  zooplankton  -  to  the  following  feeding characteristics  find  populations  concentrations should  are  limited  f u n c t i o n a l responses with high  i . e . animals  supply  leads  under  conditions:  Where z o o p l a n k t o n should  above  be  must  be  of food.  at  of  food  initial  coping  Furthermore, the  independent  ( i . e . i t should  good  by  one  slopes  with  initial  low slope  the p r o d u c t i v i t y o f the food  be t h e same  in  o l i g o t r o p h i a and  eutrophic lakes).  b)  Where  zooplankton  pressure, in  populations  one s h o u l d  find  low f o o d e n v i r o n m e n t s  environments response (a);  by p r e d a t i o n  ( o l i g o t r o p h i c ) than  be e x p e c t e d  i n the l a t t e r  limited  a d i f f e r e n t f u n c t i o n a l response  (eutrophic)In  would  are  i n high  the former, the  functional  t o have a h i g h i n i t i a l  i t would be e x p e c t e d  to  food  have  a  slope high  maximum f e e d i n g r a t e ( V ) .  There same a n i m a l  i s  nothing  from having  characteristics,  but  i n these  precludes the  a f u n c t i o n a l response with i t  p h y s i o l o g i c a l c o n s t r a i n t s would Clark,  arguments t h a t  i s  generally  not  1973)., I f t h i s i s s o , then  allow  i t  t h e two t y p e s  both  these  assumed  that  (Walters  and  of functional  34  response  2. 3- 5  just  described  particular  adaptation only  be  considered  only  set -  of  traits  competitively  conditions persist  be s i g n i f i c a n t  identifying A  -  i.e.  An  2 .  represents  advantageous  o r g a n i s m s can  evolve  particular  hold  up  only  impact  optimal  have had  would t h u s be  of  two  relatively  theory  discussed  environments.  considerable  seasonal  which c o n d i t i o n s c o u l d  strategies stable  time  ideal  for  above i s t h a t It  described  conditions  which c o i n c i d e s w i t h  above,  consider  the  as  ignore  predation  early spring  will an  may  be  or the  one  particularly  over  a period  zooplankton critical f o r the  (phytoplankton  of  other i f time  lifespan  stage moment  avoidance  may  for  favour  a particularly  of adaptation.(such  even there  persist  e x a m p l e , s u p p o s e we  But  variation,  which i s e i t h e r comparable i n l e n g t h t o  For  to  tactics  to e q u i l i b r i u m communities.  w e l l i n seasonal  during  aspects  those  t h a t t h e e q u i l i b r i u m p r e d i c t i o n s o f S e c t i o n 2.3-4  periods  history.  i f  adaptations.  major l i m i t a t i o n t o the  environment with  the  an  generally  l o n g enough f o r t h e i r  equilibrium situation  applies explicitly  w e l l be  and  that  f o r e n v i r o n m e n t a l c o n d i t i o n s t o which t h e y  to respond.  or  of Figure  t o p a r t i c u l a r e c o l o g i c a l c o n d i t i o n s would  ecological  not  those  Discussion Any  it  would r e s e m b l e  of  life other  mechanisms)  bloom) p e r i o d . ,  F O O D  F i g u r e 2.  C O N C E N T R A T I O N  Types of f u n c t i o n a l response hypothesized f o r f i l t e r - f e e d i n g zooplankton. Response (a) should c h a r a c t e r i z e p o p u l a t i o n s l i m i t e d by food a v a i l a b i l i t y o r i n h a b i t i n g o l i g o t r o p h i c waters, and (b) should be t y p i c a l o f p o p u l a t i o n s i n h a b i t i n g e u t r o p h i c waters and l i m i t e d by p r e d a t i o n p r e s s u r e .  36  Overwintering low,  o r newly h a t c h i n g  while food  tend  r e s o u r c e s are abundant.  t o f a v o u r forms with  -i.e., able  high  to  However, l a t e r  low.  One of  would  mechanical  efficient seston  habitually  and  food c o l l e c t i o n ,  concentration.  populations  could,  on a d a p t i v e  lesser  food  i.e.  presumably  animals  densities.  l e v e l s a r e h i g h and f o o d  limited  that  regimes to  are  (in this  have  evolved  mechanisms t o p e r m i t  high f i l t e r i n g  The a p p e a r a n c e o f t h e s e changes b e i n g  other than  importance a t that time.  variability  rate  rates  at  patterns  sufficiently  very low would  slow  that  d u r i n g some p e r i o d , a p p r o a c h e q u i l i b r i u m ,  traits  environmental  be  zooplankton  physiological  depend on e n v i r o n m e n t a l  the  expect  are  growth  i n t a k e a t high food  d o m i n a n t summer s p e c i e s o r g e n e r a t i o n s )  some  and  food  specific  T h e s e would  i n summer* z o o p l a n k t o n  characteristic case  maximal  populations  Such c o n d i t i o n s would  t h e most r a p i d  production i n d i v i d u a l s .  obtain  generally  zooplankton  f u n c t i o n a l response They p r o b a b l y  changes b e i n g f a i r l y  present permit  in  a  recovery  from  the  a l s o depend  predictable.  zooplankton  being o f on  (Natural  population  would  o c c a s i o n a l unexpected  condition.) T h e s e c o n d i t i o n s may e x i s t which a m a j o r i t y o f t h e a n i m a l s These l a k e s probably  i n t h e OBG F o r e s t L a k e s , used i n t h i s s t u d y  r e p r e s e n t a good example  seasonal  lakes.  There i s , f o r example, very  variation  i n grazeable seston  concentration.,  were drawn.  of f a i r l y little (In  from  stable  seasonal  fact,  for  37  t e m p e r a t e l a k e s i n g e n e r a l , t h e r e i s some s u g g e s t i o n 1977)  that  although  large seasonal  total  variation,  may r e m a i n q u i t e  phytoplankton  the grazeable  (Gliwicz,  b i o m a s s may h a v e a  fraction  of  plankton  constant.)  S e v e r a l c o n t i n u i n g s t u d i e s on t h e l a k e s o f t h e UBC F o r e s t (Neill,  Northcote,  Baiters,  p e r s . comm.)  have  c o n s i d e r a b l e i n f o r m a t i o n about s e v e r a l s p e c i e s o f used  in  t h i s study.  A n a l y s i s of t h e i r  i n d i c a t e s t h a t some o f t h e s e feeding  strategy  summer  ones  probably switch  mechanism  species,  response  For  Daphnia  to  unreasonable a single  per  There  may  to  respond  pnlex,  have  copepodite  stages  kenai in  which  the  developmental  changes  in  found  a  tremendous  of  food  similar  plasticity  within a given clone, i n  factors.  t o expect  clone exhibiting  Diaptomus  some  (1977)  and p h y s i o l o g i c a l l y ,  critical  of  few g e n e r a t i o n s a r e  to  Krepp  to  environmental  most  to  would a l l o w t h e f e e d i n g b e h a v i o u r  example,  therefore,  susceptible  year,  be  It  to find  would spring  feeding curves l i k e  2, and summer g e n e r a t i o n s w i t h  The lived  which  generations  morphologically  Figure  limited.  patterns  example, t h e r e a r e about  a r e f o o d l i m i t e d . . The f i r s t  conditions.  of  of Daphnia rosea  not food  different  For  zooplankton  history  s p e c i e s m i g h t be  adaptation.  seven generations  life  yielded  type  not  be  generations  curve  "A" f e e d i n g  "B"  of  curves.  period f o r populations o f the longerseems July  to and  be early  during  naupliar  August*  and  when f o o d i s  38  scarce. well  The f e e d i n g c h a r a c t e r i s t i c s o f  have  adapted  to  best  these  accomodate  animals  could  t h i s period of food  limitation. The  s m a l l e r c o p e p o d s o f t h e UBC F o r e s t  oregonensis  and  generations not  food  timing  Diaptomus  per year  limited, of  possible  these  that  by  temperature  unreasonable  - winter  generally  which  three generations generations  i s .  model,  could  or photoperiod.  t o expect  be  strategies  2.3.6  to find  I n t h i s case  response  differentially tantalizing evolutionary k.  seasonal  different  "ft"of  may  be  i t would n o t b e Figure  2  for  "B" f o r t h e o t h e r  which p r e d i c t e d t h e e x i s t e n c e  possible  to  an  find  equilibrium  the  same  two  situations.  From T h e L i t e r a t u r e  Speculating  and  the theory  i n various non-equilibrium  Evidence  The  quite  o f f e e d i n g s t r a t e g y was b a s e d on  i t still  which a r e  T h e r e c o u l d even be g e n e t i c d i f f e r e n c e s c u e d  Thus; a l t h o u g h  o f two t y p e s  three  i s p r e d i c t a b l e , and i t i s  t h e summer g e n e r a t i o n , and p o s s i b l y r e s p o n s e two.  Diaptomus  produce  and s p r i n g g e n e r a t i o n s  a n d a summer one  the  physiologically.  tyrelli  Lakes,  about  ecological  advantageous  activity.  functional  Host d i s c u s s i o n  significance  consequences  has  responses focussed  of the Hichaelis-Henten  T h i s e m p h a s i s may be m i s l e a d i n g  of i s on  a  the  parameters  7  however, f o r t h e r e i s  39  considerable the  evidence  observed  due  patterns  to c o r r e l a t i o n ,  subject  which  generated  field  of  (1967) h a s  considered  2.3-4.  between  Hichaelis-Henten  He  of  k  characteristic plankton  with  nutrient-rich and  Dugdale  done  at  k  higher  k and  phytoplankton low  probably  low  a  interesting  studies,  dynamics.  Dugdale  areas.  highfc This  was  to those  k and  also  productivity  V and  discussed  tropical  values in fact  for  observed  in  Baclsaac  experiments  w a t e r s were c h a r a c t e r i z e d by p h y t o p l a n k t o n  with  V values,  V values. populations  and  while  This  and  while  prevail by  to  species  regions,  should  Sea  lead  Ocean.  low  Bering  tradeoff  V should  V) v  in  Pacific  ambient n u t r i e n t Parsons  nevertheless  t h a t an e v o l u t i o n a r y  parameters  1  various s t a t i o n s i n the  and  be  (1969) i n a s e r i e s o f n u t r i e n t u p t a k e  Hutrient-rpoor low  high  some  Thus  p a r a m e t e r s may  is  phytoplankton  speculated  (and  of  It  that are s i m i l a r  section  values  independent.  s t r a t e g i e s f o r growth o r n u t r i e n t uptake  marine p h y t o p l a n k t o n  low  not  evolution.  has  i n the  k are  of Hichaelis-Henten  not  especially  of  t h a t V and  e a t r o p h i c s t a t i o n s a l l showed  would  seem  to  of o l i g o t r o p h i c a r e a s  indicate  that  are adapted  to  concentrations.  Takahashi  (1973) have p r o p o s e d  a mechanism  Host s t u d i e s o f p h y t o p l a n k t o n d y n a m i c s use Hichaelis-Henten r e l a t i o n s t o d e s c r i b e g r o w t h and n u t r i e n t u p t a k e a s a f u n c t i o n of n u t r i e n t c o n c e n t r a t i o n . 1  40  which  could  enhance  considerable between of  7 , large  environments small  and  celled  Eppley e t  i t  will  species of  al.  of  different  in  k values  of  to  were  terms  model  phytoplankton  of  upwelling V,  Eppley  distribution be  of  (with  coastal  currents,  small and  size.  species  plankton  k)  for  while  will  Thomas  be  (1969)  and  characteristics found  among m a r i n e  evidence  environments  c o n t r o l l e d by  differences  species. (1973 3  ) proposed the  as  to  algae  in  constant  the  small  of  Michaelis  large celled  strong  a  phytoplankton depend to  conditions, be  basis  physiological differences  m a r i n e p h y t o p l a n k t o n and  species  Figure  expect green nutrient)  of  s t a b l e seas.  Goodman e t a l .  competition  a  that  (with  among t h e  succession  the  environmental c o n t r o l of c e l l  n u t r i e n t r e g i m e s may  in  On  (1969) measured n u t r i e n t u p t a k e  to suggest that  begin  and  dominate  areas  a l a r g e range of  shown  rate  predicts  k)  characteristic  for  growth  shows s t r o n g  particular,  large  are  uptake, they c o n s t r u c t e d  dynamics t h a t In  tradeoff.  s m a l l - c e l l e d phytoplankton species,  maximum  nutrient  a  evidence that there  l a r g e and  both  such  mechanism  underlying  species.  Inv this  on  dominate  phosphate under  then diatoms a  depleted  and  f u n c t i o n a l responses  finally  case;  alone,  early  little  seasonal  later  one  spring as  i f would (high  nutrients  blue-greens during  summer  stratification. As  f a r as  work on  zooplankton  i s concerned,  few  studies  41  Figure  3.  F u n c t i o n a l responses proposed by Goodman et a l . (1973) to e x p l a i n seasonal s u c c e s s i o n of phytoplankton s p e c i e s .  42  of  this  nature  have  been  (1967) a r g u m e n t s a b o u t zooplankton  the  most  (high  rate  However,  liability,  and  conversion  of  -  animals  be t h o s e  increase)  who  harvest  Productivity  i s favoured  in  this  habitats wastefulness i s a  should  favour  offspring.,  efficiency  of  The most f i t g e n o t y p e s  which c o u l d r e p r o d u c e  (1975)  succession  has  at the  lowest  food  productivity  proposed  that  theuse  of  such  a r g u m e n t s c a n be a v a l u a b l e t o o l f o r i d e n t i f y i n g a t many l e v e l s o f d e t a i l and f o r  hypotheses.  of n u t r i e n t  uptake  He has i l l u s t r a t e d  strategies  as  they  generating  t h i s w i t h an example relate  to  seasonal  of phytoplankton.  Gliwicz exist  (1977) has h y p o t h e s i z e d i n food  productivity,  the anterior  of  that  zooplankton  different  strategies  i n lakes of different  d i f f e r e n c e s i n food  particle  size.  among v a r i o u s C l a d o c e r a n s p e c i e s i n e u t r o p h i c  differences This  limited  because  He h a s o b s e r v e d ,  grazed.  t h a t i n an uncrowded  do so w a s t e f u l l y .  crowded  into  be a p p l i e d t o  w h i c h would b e t o o l o w f o r h i g h  parameters  testable  lakes,  will  Wilson's  t o reproduce.  evolutionary  should  in  food  a level  Halters  system  of  evolution  w o u l d be t h o s e  level  in  even i f they  intrinisic  situation.  here  They s u g g e s t  t h e most f i t g e n o t y p e s food,  Mac A r t h u r ' s and  " r and K s e l e c t i o n " c o u l d  feeding habits.  environment,  done.  in  the  upper  size  limit  of  particles  d i f f e r e n c e i s a p p a r e n t l y caused  by d i f f e r e n c e s  width o f the carapace  through  crevice  which  43  water  and  process-  food  He a r g u e s  feeding rates, because  the  a l g a e from  and  2-4  t h a t narrow c r e v i c e d  during the f i l t r a t i o n species,  narrow g a p s between c a r a p a c e  l a k e s , the  because  with  lower  edges prevent  summer  zooplankton  appendages. should  b e c a u s e t h e r e i s no n e t p l a n k t o n  they  passes  large  be  In wide  interference,  c a n remove a l a r g e r amount o f f o o d from t h e through  the f i l t e r i n g  chamber.  Classification I  have o u t l i n e d  measure f u n c t i o n a l zooplankton,  to  three o b j e c t i v e s  responses  tend  how  -  to  variable  or  constant  t o environmental  these  evidence  conditions.  r e s u l t s o f t h e s e e n d e a v o u r s m i g h t make i t p o s s i b l e t o  classify  the  zooplankton  according to their variety  study  t o b e , a n d t o l o o k f o r any  adaptation of the responses The  f o r this  o f many s p e c i e s o f f i l t e r - f e e d i n g  determine  f u n c t i o n a l responses of  sucked  s h o u l d b e d o m i n a n t i n e u t r o p h i c l a k e s i n summer  forms,  water t h a t  are  e n t e r i n g and c l o g g i n g t h e f i l t e r i n g  oligotrophic creviced  particles  of  strategies zooplankton, functional  functional  morphological that  into  are  i t i s response  a  responses.  forms  exhibited  possible  small  and by  that  number  groups  In s p i t e o f the r i c h overall  life  herbivorous only:  f o r m s and p a r a m e t e r  of  history  freshwater  relatively  few  values a c t u a l l y  occur  44  in  nature  because t h e r e  conditions  that  a r e few  persist  long  significant.  Classification  response types  should  seasonal  o r g a n i s m s t o the A  and  such  temperature, or the  enough of  changes  in  models.  work a r e  be  set  of  i n applying values  virtually  drawn f r o m  a  under a v e r y  for  all  experimental the  freshwater  small  set  of  the  limited  the  Oriob,  often  power, b u t  the  q u a n t i f i e d by  lack  of  1972)-  show  in  the  The  and  data  values  experiments  values.  concerned, the  r e g i o n o f low  food  modelling  experiments. a  few  these  few  conditions (DiToro  components limited  f u n c t i o n s of the  parameter  aquatic  f o r only  physical  how  functional  covering  guesswork,  to  marine  sophistication  biological  f u n c t i o n a l r e l a t i o n s h i p s are confused  a  educated  measured  determined  set of c o n d i t i o n s , yet  r a n g e of t h e  a l . , 1 9 7 0 ; Chen and  usually  or  competitive  isolated  original  computer  to  loading  biological  far  models  responses  i n f o r m a t i o n : about  i n models  these  p r e d i c t i o n of  experimentally  r e s u l t s h a v e been i n c o r p o r a t e d outside  and  functional  nutrient  These e x p e r i m e n t s have y i e l d e d parameter species  by  community.  can  in  adaptively  i n t r o d u c t i o n of predaceous o r  Parameter  responses  environmental  be  community  f u n c t i o n a l r e s p o n s e s would a l s o y i e l d we  to  zooplankton  aquatic  as  comprehensive  general  s e t s of  s i m p l i f y understanding  succession  perturbations  distinct  made  necessary  A s f a r as  of  only  system  et  by are by  feeding  guesswork i s  most  concentrations, precisely  45  where t h e e x a c t form effect  on  the  whole system  of  the  qualitative  ( s e e Lehman,  relationship and  has  quantitative  i t s greatest  behaviour  used  t o manage a q u a t i c s y s t e m s - f o r e x a m p l e , t o p r e d i c t in  nutrient  or s i l t  (DiToro e t . a l -  (1970)  6  -  Gritton  (1971)  Fransisco  Bay,  parameters must is  loading,  Jamaica  Bay;  Washington).  a r e g e o g r a p h i c a l l y and  be r e d e t e r m i n e d  an a l m o s t  f o r each  impossible  system  experimental  an enormous s i m p l i f i c a t i o n  functional  r e s p o n s e s c o u l d be  From my initial  experiments, of  by c o m p a r i n g  over a range  -  determined  from  hoped  obtain  San curve  similar,  they  modelled;  this  endeavour., of effort  etc.  It  would  i f zooplankton  a few  biological  alone.  indication  parameters  t o be  of  Leendertse  response  specifically  new  aids  results  (1972)  Orlob Unless  represent  characteristics  Delaware a . ; 6  Chen  as  water f l o w r e g i m e ,  - Great Lakes,  Lake  the  1976).,  Q u a n t i t a t i v e models are b e i n g i n c r e a s i n g l y  change  of  I  to  the g e n e r a l i t y  with those reported i n the  l a k e s and  the  by c o m p a r i n g  literature.,  least  an  of zooplankton feeding  feeding curves f o r  of d i f f e r e n t  at  same  species  these  results  46  3 EXPERIMENTAL DESIGN  In  order  to  obtain  estimates necessary,  for  the the  decided t o c o n s i d e r a range by t h r e e  spectrum objectives  above,  species of  2.  level  of lake  3.  time  of  zooplankton productivity  year  Specifically, procedures  to  I  (this determines  proposed  to  productivities,  f e e d e r s from  and  to i n s i t u  were r e p e a t e d a t i n t e r v a l s f r o m Fortunately  there  are  lakes of different  seston)  use ; i d e n t i c a l ; e x p e r i m e n t a l responses  a s e r i e s of l a k e s of  oligotrophic  conditions.  The  experiments  early  spring through  near  Vancouver  levels  a  fall. number  of p r o d u c t i v i t y ,  4 and  5 show t h e g e o g r a p h i c l o c a t i o n s o f t h e w a t e r b o d i e s  and  T a b l e I summarizes t h e i r  major h e r b i v o r o u s z o o p l a n k t o n  were: 1..,  to shallow  Daphnia  pulex  eutrophic.  Figures  characteristics. available  from  of  ranging  deep and  lakes  of  different  from  i n t h i s study.  and  t o t r y to maintain experimental c o n d i t i o n s  as p o s s i b l e  accessible  water t e m p e r a t u r e  t r y t o measure g r a z i n g f u n c t i o n a l  major p a r t i c l e  The  I  factors:  1.  as c l o s e  outlined  of experimental conditions defined  amount o f f o o d p r e s e n t i n t h e  the  of f e e d i n g parameter  used ;  these  47  F i g u r e 4.  Map showing lakes from which zooplankton were taken f o r t h i s study.  Table  I. C h a r a c t e r i s t i c s  Index o f Productivity *  Lake  Eunice  Max. zoo biomass mg/m^ d r y  o f t h e l a k e s used i n t h i s  Mean depth m.  Mean area acres  15.8  4 5.5  Daphnia r o s e a Diaptomus t y r e l l i Diaptomus k e n a i Holopedium qibberum Diaphanosoma b r a c h y u r u m  51.7  Daphnia  1  2500  Katherine  1  2500  7.5.  .Placid  2  3500  4.3  • •  • •  \  4.0  i •  Pond, UBC  Campus  1  0.2  Loon  .4  30.0  Deer  .5 .  Lab c u l t u r e f r o m eutrophic Rock L-.  5  3.5  Zooplankton studied  Daphnia r o s e a Diaptomus o r e q o n e n s i s Holopedium gibberum C e r i o d a p h n i a sp. Daphnia pulex  2375  C e r i o d a p h n i a sp. Daphnia r o s e a  87.  Daphnia  ( r e a r e d f o r about 1 y e a r Daphnia i n very eutrophic laboratory aquarium) . |  * 1.= v e r y * 5 = very  oligotrophic eutrophic  rosea  . 0.01 •  •  10000  study.  pulex pulex .  50  2.  Daphnia  3.  Ceriodaphnia  4.  Holopedium  5.  Diaptomus  kenai  6.  Diaptomus  oregonensis  7.  Diaptomus  tyrelli  8.  Diaphanosoma braohyurum  Each  species  rosea  was  sp.  qibberum  present  in  more  than  one  of the  lakes  of  Animal  investigated. As  part of another  Resource  Ecology  t h e f o u r upper Gwendoline,  has  been  Placid  and  lakes  and  study.  the  Katherine)  phytoplankton. a  Gwendolines data  C.J.  in  conducting  additional of my  (Drs.  and  zooplankton  project at  on  series  the  Institute  falters UBC are  and  forest  Horthcote),  (Placid,  regularly  In a d d i t i o n , of  T.G.  Dr.  Eunice,  sampled H.E.  for Heill  enclosure experiments  Thus t h e r e i s a c o n s i d e r a b l e a r r a y  the z o o p l a n k t o n  p o p u l a t i o n s used  on of  f o r most  51  3. 1 C h o i c e O f T e c h n i q u e Methods f o r m e a s u r i n g herbivorous  zooplankton  Virtually  all  filtering  /  following  three  1.  current  feeding  are s e l l work  zooplankton  used.  feeding  by E i g l e r  measurement done  rates  with  of  of  (1971) .  zooplankton  v a r i a t i o n s of the  methods:  radioactively is  i s  and  summarized  on  rates  basic  Allowing  filtering  to graze f o ra  labelled  food.  short  T y p i c a l l y , **C o r  T h i s works w e l l when t h e f o o d  but  f o r experiments with  are  biased  time  on 3 2  P  i sunialgal,  natural seston,  and p o s s i b l y u n i n t e r p r e t a b l e  the r e s u l t s because  of  d i f f e r e n c e s i n u p t a k e o f t h e l a b e l among t h e v a r i o u s components o f t h e s e s t o n . , 2.  Adding  low  cells  (generally  allowing the on  concentrations  zooplankton  assemblage. the s i z e  time  in  seston,  to  the  natural  and  concentration  seston  graze f o r a short  cell  time i n  dependent  and may be  labelled  and  severely  size  i s not  o f t h e range o f s i z e s i n t h e s e s t o n .  zooplankton a  " P - l a b e l l e d tracer  The r e s u l t s a r e o b v i o u s l y  i f  representative Allowing  to  of t h e t r a c e r c e l l ,  misleading  3.  yeast)  of  volume  t o feed of  cultured  measuring after  for  the  the  long algae change  feeding  periods  of  or natural in  period.  cell This  52  technique since  is  the  extensively  Coulter  determination because  of  results  can  of  production, zooplankton  Counter food  the  long easily  and  by  on  (viable) been  of cells  possibly  an  zooplankton this  altered  by  al.  by  Porter  effect  of  that  (1976)  have  modify  particle  size  large  increases i n small  cell  count  method  should  colonies  This  change as  gut  small have  there  is by  •control* vessels for rather  ineffective dynamics  how  O Connors 1  zooplankton  particles.  the  are  t h i s well with  distributions,  as  and  into  Also  often  a  can  causing  Finally,  the  filtering  rate  course  means t h a t t h e f o o d  little  gut,  of  fertilization  illustrated  during  of For  passage,  assumes t h a t t h e  remains n e a r l y constant experiment.  the  zooplankton.  s e r i e s o f e x p e r i m e n t s showing  pellet  c e r t a i n types  phytoplankton  presence of  the  effects  (1975).  are  However,  fecal  in  algal  experiment  seems  the  algae  The  easy  dynamics.  by  or c o l o n i e s d u r i n g  of  i t  by  seston  algal  excretion.  type  because  et.  large  observed  relatively  various  passage  a l g a e , n u t r i e n t u p t a k e by breakdown  studies  time necessary,  biased the  gut  marine  allows  feeding  be  viable  in  concentrations-.  digestion  example,  used  of  the  concentration  p o s s i b l e over the  course  53  of  the experiment, but  may  in  pointed this  fact out  the experimental  The  who  densities  small  in  For use  an  my  feeding  which  Seston  1969;  grazing  long  incubation  Buikema,  Frost;  1975).  originally  below  samples  of g r a z e d  b o t t l e counts.  this  under  interpretation  a  surface later a  yielded  1973;  decided To  to  continuously  of  the  i n the  results  in  lake.  laboratory  microscope.  b o t t l e s were f r e q u e n t l y  Several  which  cell  higher  than  S i m i l a r r e s u l t s have b e e n o b s e r v e d  (1975) and  investigated  the  were e v a l u a t e d  experiments  Zaret  method a b o v e .  b o t t l e s were mounted on  suspended  preserved  of  the  zooplankton  1970;  by  Gliwicz  phenomenon  (1975). and  h y p o t h e s e s t o e x p l a i n i t , a l l o f which imply in  by  in  concentrations  has  largely  I conducted a s e r i e s of p r e l i m i n a r y experiments  by c o u n t i n g  B e e r s and  high  with  e x p e r i m e n t s I had  concentrations  control  been  by  the  wheel  months  implied  test  closed  rotating  very  Seen,  third  (1971)  been<widelymisused  volumes  Sladecek,  i n s i t u v e r s i o n of the  technique,  seems t o have has  S  Rigler  difficulties  combine  (Hargrave  Kryutchkova &  he  method  experimenters  periods  long i n c u b a t i o n times i t  decrease considerably.  assumption, but  ignored.  with  of l o n g  Porter  by  (1975)  proposed  several  severe  problems  incubation cell-count  feeding  experiments. A second s e r i o u s disadvantage  to  this  method  was  the  54  difficulty food  of q u i c k l y  samples.  measuring  Manual  cell  the c e l l  c o n c e n t r a t i o n s of  c o u n t i n g proved  too tedious  time consuming f o r the l a r g e  number  planned,  t o use a C o u l t e r C o u n t e r  of  the  and  I was  possibility  damaged by s a l i n e Because  of  reluctant that  of  feeding  some o f t h e f r e s h w a t e r c e l l s  because  might  these  problems,  I  abandoned  the  i n l a k e water to  to graze  (32p)  yeast  success  much  1973;  assumes  a l l  efficiency  many w o r k e r s ,  graze size  from most  of the Frost  pacificus food  size.  Haney, food  the  has  amount  b e e n used  reported  (Burns,  1969;  of  are  particles.  and  types  although  no  Burns  feeding rates of 6  filtered  Bigler,  the  same  efficiencies  have b e e n s t u d i e d by rule  the r e s u l t s ,  i t seems t h a t i n g e n e r a l  effectively  on  range  1967;  i s that i t  with  Filtering  comprehensive  a size  altered  with: considerable  work on  of food  which  radioactive  1971)w. I t s main d i s a d v a n t a g e particles  sizes and  small  zooplankton  t h e n a t u r e o f t h e s e s t o n was  as t h e l a b e l l e d  different  emerged  of  zooplankton  Crowley,  for  that  This technigue  in  freshwater  sufficiently  cells  very l i t t l e .  f o r a short time  which  cell-count  were  been a d d e d a  be  suspension.  in  had  and  experiments  method i n f a v o u r o f a t r a c e r t e c h n i g u e allowed  the  that  has  yet  zooplankton  d e p e n d s on  the  animal. (1972) measured as  a function  the  ingestion  rates  of  of food c o n c e n t r a t i o n f o r a  Haximum i n g e s t i o n  Calanus range  r a t e s ( i . e . r a t e s f o r high  of  food  55  concentration) 11  u to 94  ingestion  were i d e n t i c a l  u diameter,  at  rates  slightly  (1974)  Poulet  were fonnd  opportunistic  with  particle  grazing  f r o m . one  pressure  a t e whatever  biomass. by  another  Wilson  sizes  and  greater  (1973) at  Host size  animals, of s i z e s  and  1.5  smaller  than  ingested  most  mm  mm  indicate  diam) e q u a l l y  well,  whereas  nannoplankton  preferentially.  the f i l t e r i n g  rate  in  the  that  can  its  i.e..the terms  of  observed  most  abundant  particles  found  that  in  ate  the  smaller  HcHahon and  small  a large  range  Daphnia  pulex  bacteria.  larger  (1975) •Daphnia  plankton  Diaptomus Rigler  magna t o be  and  Daphnia  HcNaught  The net  u)  that  small  Bogdan and  minutus.  of l a r g e Daphnia  and  body  for  (1.5  bacteria  u diam.) and the  zooplankton  handle  differentiation,  o b t a i n e d by  ( <22  to seasonal  especially  Lampert(1974)  q a l e a t a and D i a p t o m u s  nannoplankton  over  very  availability.  preferentially  were  a  to another -  the l a r g e s t  selectivity,  without  be  shifting  abundant  i n length ingested  (28 u) 1.5  their  however,  a c a r t i a t o n s a , was  large zooplankton  well.  results  Daphnia  was  range  by  from  particles.  to  t o adapt  spectrum  size  studies  food  that  equally  algae  for  size  t h e same t i m e t o i n g e s t  larger  Similar  ability  marine copepod,  freshwater  than  an  minutus  to feed n o n s e l e c t i v e l y  determines  larger  size  p r o p o r t i o n than  ranging  higher f o r l a r g e r  Pseudocalanus  feeder,  sizes  lower food c o n c e n t r a t i o n s  v a r i a t i o n s i n food  animals  for particle  ( >22  u  ingested  (1965)  found  independent  of  56  size  of  food  (1968)  found  the  s i z e s of  maximum  several species  0.9  An  measure i n g e s t i o n  overview  {1976),  He  of  u  of  that  ingested  by  Bosmina.  and  length.  However,  rates.  i t is  not  necessary  to  scan  published to  with  distributions  or t o a c t i v e l y s e l e c t c e r t a i n p a r t i c l e s  have  preferential  filtering for  apparatus  animals to In  filtering  as  be  discussed  upper  limit  cladoceran  The for  my  that  Gliwicz  particles  related to  order  considering  the  imply a  tendency  the  that as  saturated, explain  (1977)  grazed  was,  width of  smaller  Frost's  found  (1972)  that  f o r a number  the  the  gap  the of  between  margins. OBC  forest lakes,  experiments,  should the  in  will  partly  This could  above.  are  fall  u p t a k e of  w i t h w h i c h I was  characterized  A b o u t 80S  4 u diameter range.  cells  sieve*  size  particles.  becomes  of  species,  phytoplankton. 2 -  'leaky  captured.  observations size  a  Simply  by  credit  particle  t h i s same a n a l o g y i t i s p o s s i b l e  apparatus  particles will  ingestion.  'select* larger  terms of  carapace  ability  recently  zooplankton  to  an  size  body  Barns  3  D a p h n i a and  s i z e s e l e c t i o n was  claims  18,000 u .  to  3  particle  i t proportional to zooplankton  d i d not  Boyd  over a range of  measured  different  she  cells  of  I n my  the  seston  by  mainly  concerned  small  forms  particles f a l l  experiments  then,  the  i n t h i s same s i z e r a n g e , i n o r d e r radioactive c e l l s  reflect  to  in  of the  tracer assure  accurately  the  57  uptake the  of seston p a r t i c l e s .  t r a c e r o r g a n i s m f o r t h i s and  cell  size  was  about  2  medium, t h e c e l l s t e n d e d clumped  together,  edible  by  addition*  the  D e s c r i p t i o n Of  feeding  other  to e x i s t  local  i n the  t o c u l t u r e and  or with  aggregates.  i n t h e a i r and  Individual in  liquid  2 or 3  cells  This yeast i s  fresh  waters,  and  proposed experiments. l a b e l with  3 2  is In  P.  experiments  measured  . filtering  and  r a t e s as f u n c t i o n s o f f o o d c o n c e n t r a t i o n under a  wide  3 2  P  zooplankton  labelled  yeast  as  a tracer  either n a t u r a l seston or C h l o r e l l a  a s t h e main f o o d  F i g u r e 6 shows a s c h e m a t i c  of the  The  UBC  Bhodoturala  slants until  about a  yeast  was  Carrier-free Immediately suspension  outline  Microbiology  yeast stock*  deionized  as  Methods Used  range of c o n d i t i o n s , using  the  chosen  as p r e p a r e d  singly  in larger  r u b r i s was reasons.,  diameter;  zooplankters  i t i s easy  These  u  but not  v e r y common, p r e s e n t  3.2  Bhgdotorula  3 2  P  before was  rubris.  an  to the  I t was  maintained  medium  experiment  centrifuged  distilled  s u p p l i e d the  i n a peptone-dextrose  added  and  a  component.  method.  week b e f o r e e a c h e x p e r i m e n t ,  suspended was  Department  and  a  few  few  ml  rinsed 3 2  on  not  agar  when some o f  liquid  three  w a t e r t o remove a l l P  original  medium.  days of t h i s times  later. yeast with  incorporated  58  \  I  CoUec\  lake  vUxtcr  CoUccA 2ooplank\on Vvorn lake  CvU jre vjeast UWledl  \  I |  Knsc and cVUo^c  l*>i Ui too -  "Sort ?.6o | pto-M. toon tolo ^cirUiUatioi | VtO-U |  M e a s u r e . rt\(3-voacAv\/vUj  ScmViUaVion  F i g u r e 6.  Calculate  ^ I c r w i Vales  Calculate  Ceciti/v^ ca\e.i  Experimental c o n f i g u r a t i o n .  m5i  59  into  the  yeast c e l l s .  haemocytometer, yeast  to  a  cells/ml the  the  most d i l u t e  animals  and  Since the I  had  proved volumes  of  adopted  a  cells, f a r too  with a  lake  a  'hot*  2000  yeast  the weight  populations,  water  were  of  the  seston  in  tried  by  membrane Horris  filters  use,  (Specially  serves as a wetting appropriate  ordered  and  order filters  of  for  levels, obtain  damage  but i t  slow,  direct apparatus  (1972)-,,  of d i s t i l l e d  reduce  without  any  Since  detergent  i n warm d i s t i l l e d  to  the  eventually I  dry weight as  litres  a to  processing  Yentsch  of their  a g e n t , c a n n o t be  quantities  avoid  stirred,  were s o a k e d  in  to  f i l t e r s , u s i n g an  f l u s h e d w i t h a b o u t two  before  order  experiments;  continuously  large  seston  reverse f i l t r a t i o n *  practical  kept  incubators.  low  To  the  collected  b e f o r e , and  environment  g e n e r a l l y had  s l o w t o be  design  and  immediately toxicity.  of  in controlled  I first  of  1967), t h e  a day  1/3  n a t u r a l zooplankton  membrane f i l t e r s c o n t a i n 2-3%  for  with  1 ml o f  about  ( i . e . about  water r e g u i r e d i n t h e s e method  filtration  (Cahn,  give  range o f food c o n c e n t r a t i o n s .  t o be  b a s e d on  adding  of the experiment o r the n i g h t  temperature  phytoplankton  measured  s e s t o n c o n c e n t r a t i o n used.)  concentrate  sufficient  that  would  f e e d i n g medium  various lakewaters  to  d e n s i t y was  so  chamber  large quantities  constant  cell  diluted  experiments with  e i t h e r t h e day at  then  grazing  in  For  Yeast  water water  possible  detergent,  which  used t o f i l t e r w a t e r . )  seston  concentrate  and  lake  60  water f i l t r a t e  were  concentrations  recombined  desired.,  instead  of natural seston,  obtain  lake  filtrate.  resuspended i n the concentrations  to  For the  give  experiments  Then  filtrate.  beakers per  (250  was  Generally  I  were  ml  i f more t h a n one  beakers); I was  sizes  of  (5-50) was  The  f o r 2-3  that  For  hours at later  2-3  hours  concentrations, work  practice  i s to  and  three  five 2.0,  food  and  5.0  replicate  placed  i n grazing  250  the  were  same numbers o f e a c h  class  several i species  number o f a n i m a l s i n e a c h concentration  then the be  left same  in  of  reported starve  would  from  I  used and  to  at four  periodically  was  for  chose to  to t h e i r standard  literature.  zooplankton  two  to  settling.  to adjust  the  incubator  concentration  concentration,  because t h i s in  vessel  food  the  food  measured.  seston  animals  mainly  vessels  s p e c i e s or s i z e c l a s s  feeding experiments I a r b i t r a r i l y  for  similar  centrifuged  hours.  each  them t o p r e v e n t most  the  the  were  r e p l i c a t e beakers f o r stirred  The  o v e r 3-4  would  and  to put  animals) .  little  they  to  used  beaker o f t e n c o n t a i n e d  zooplankton  acclimate which  (each  chosen so  change v e r y  sorted  careful  i n t o each beaker or  Chlorella  followed  1-0,  0.5,  food  concentration.  Zooplankton  abundant,  was  Chlorella  0.1,  (approximately  various  using  same p r o c e d u r e  times n a t u r a l lake c o n c e n t r a t i o n s ) , with ml  the  24  One  allow  various  food  practice  for  other  hours  common  prior  to  61  feeding  experiments,  a s I was  trying  At was  t h e end  stirred  Zooplankton varying  b u t t h i s d i d n o t seem a p p r o p r i a t e h e r e ,  t o measure " u n d i s t u r b e d " f u n c t i o n a l of the a c c l i m a t i o n into  the  from  5 to  15  minutes.  beforehand  animals as a f u n c t i o n  to  passage allow  time.  the  sufficiently long  beakers  The  by m e a s u r i n g  of g r a z i n g  animals  to  feed  for  any  radioactive  immediately  They were t h e n  k i l l e d by i m m e r s i o n  diluted  with  water.  The  prevent  defecation  1969).  with d i s t i l l e d  liquid  suspension) vials  programmable each  grazing  were  uptake i n the estimate  enough  counted  scintillation and were  Bray's counted  to  become  scintillation chamber  but  were  not  t o be d e f e c a t e d .  s e i v e and,  still  w a t e r and r i n s e d  in  the  water. and  thoroughly  w a t e r i s an a n a e s t h e t i c and  during from  subsequent  each  vials.  Cabosil  scintillation a  Nuclear  counter. filtered  processing  replicate  by s p e c i e s and  on  of  wanted  i n a mixture of a l c o h o l  carbonated  Zooplankton  m e a s u r e d , s o r t e d , and  before  radioactive  times  anaesthetized with carbonated  chloroform  in  particular  material  were  separate  animals.  •hot* juedium f o r t i m e s  long  seive,  (Burns,  the  yeast  F o r measurements o f f e e d i n g r a t e , I  were t h e n removed w i t h a f i n e  to  labelled  t i m e , t o g e t an  Animals  seems  P  r a d i o a c t i v e f o r good c o u n t i n g s t a t i s t i c s ,  enough  tap  3 2  containing  were a l l o w e d t o f e e d i n t h e  established  gut  time,  responses.  size  were  class  ( t o keep fluid  into  animals  were added  Chicago  Isocap  Aliquots of seston and  rinsed  then  for  from 3 2  P  62  counting.  Larger  samples  were  filtered  on  f i b r e f i l t e r s t o o b t a i n ash f r e e d r y weight concentrations and  (the  filtered average  per  rates,  expressed  animal  radioactivity  per u n i t  Feeding  as  for  food  i s t h e combined  yeast  the  time,  by  dpm p e r a n i m a l corrected f o r q u e n c h and control  r a t e s were t h e n  . .  dpm p e r ml. o f seston  determined  feeding factor  to  the  i t s h o u l d be  responses.  by  For  collected  that  be c o n t r o l l e d  the  water from  the  radioactivity eguation  . .  grazing time i n minutes  multiplying  filtering  feeding suspension.  warnings  impossible almost  this factor  within certain  to  any  t h e r e i s p r o b a b l y someone who  otherwise,  of  Experimental Conditions  according researchers,  and  the f o l l o w i n g  r a t e s by t h e f o o d c o n c e n t r a t i o n i n t h e  E f f e c t s Of  volume  were c a l c u l a t e d  of the z o o p l a n k t o n  the yeast--seston suspension  ml.filtered per animal per minute  3.3  values  glass  seston). Filtering  of  f o o d t h u s measured  preashed  has  of  zooplankton  measure  zooplankton  possible claimed,  experimental i n print  i s o f utmost importance narrow l i m i t s -  Of  and  course  or must such  63  control  generally  constraints  imposed  therefore,  I  experimental rinsing  conflicts  on o t h e r f a c t o r s .  carried  type  length o f grazing time,  one  or  As p a r t o f  more this  of  the study  o u t t e s t s o n t h e e f f e c t s o f a number o f  conditions - size  technique,  with  of grazing v e s s e l ,  zooplankton  o f f o o d , dosage o f r a d i o a c t i v e and a c c l i m a t i o n t i m e .  yeast,  64  RESULTS  4  4.1  Tests  4-1.1  Of  Experimental  S i z e Of The  Grazing  Chambers  influence of vessel  marine c a l a n o i d s has Cushing  (1958),  calanoids  size  on  been r e p o r t e d  Anraku  f r e s h water c l a d o c e r a n s are  Conditions  (1963).  by  feeding Marshall  1971).  Schindler  the  There  a wide r a n g e i n t h e  feeding  published  e x p e r i m e n t s - from  Burns  Rigler,  6  (Crowley,  1973)  consideration ratio that  of the  course  of  the  (Gauld,  Bogdan  number o f r e s e a r c h e r s eguation  to  concentration  during  As  McHaught, 1975)  over  1970).  The  (Haney,  feeding  already  calculate  must h a v e been  such the  important  in  used  filtering large  the  during  pointed  have i n c o r r e c t l y  ml  important  medium be  little  in  1971;  t o 500  most  no  magna.  i s , I believe, that  very  incubation.  than  v e s s e l s i z e s used  This i s especially  experiments.  experiments f o r which t h e r e food  that  found  Daphnia  6  (McQueen,  experiment.  of  and  d e n s i t y t o volume o f  1951)  (1955),  (1968)  ml  c o n c e n t r a t i o n changes  long-incubation surprising  ml  1000  rates  in selecting vessel size  animal food  1967;  t o 65  Orr  of  a r e l e s s a f f e c t e d by c o n f i n e m e n t  (Rigler,  certainly  and  I t i s g e n e r a l l y assumed  e f f e c t o f c r o w d i n g on is  behaviour  out,  a  Gauld's rate  in  changes  in  They seem t o be  unaware  65  that  this  equation  is  during  based  the  on  filtering  rate  filtering  r a t e does n o t g e n e r a l l y  changes  in  low  concentration.  food I  experimented  500  ml.  for  Figure Daphnia  seemed  tried  seemed ml,  fairly  and for  to  barely  feed  difference  of comparable  experiments  inhibit  100  ml.  pipettes).  disturbances t h e measured  probably I had  Two  modelled  after  rotating  bottomed  b a s k e t s suspended  One  consisted  Crowley's wheel,  i n 500  because  experiments  beakers  were  because  they r e q u i r e d  observed  Holopedium  of closed  100  design  and  (1973)  w h i l e t h e o t h e r used  finally much l e s s  they  configurations  ml b e a k e r s , w i t h  ml open  the  appendage  mesh  t h e a n i m a l s f r o m b e i n g t r a p p e d on t h e w a t e r 250  to  filtering  previously  seconds.  i n them.  ml  little  were t h u s abandoned b e c a u s e d i a p t o m i d s a n d  on a s l o w l y  Ordinary  made  vigorous  while.  100  were k e p t a b o u t t h e same.  Holopedium. a  of  involving  r e a c t t o p h y s i c a l d i s t u r b a n c e s by c e a s i n g  pipettes  keep  i n the region  of c o n f i g u r a t i o n s  i n 250 m l . b e a k e r s and  mounted  to  rapid  shows r e s u l t s  movements c o m p l e t e l y f o r up t o 30 I  remain c o n s t a n t d u r i n g  s h a p e s and s i z e s r a n g i n g f r o m  to drastically  filtering  Holopedium  But  of the c o n t a i n e r  involved  rates o f diaptomids stopped  the  of constant  experiment.  with a v a r i e t y  7, w h i c h rosea  Methods which animals  of  Zooplankton d e n s i t i e s  Generally, the size (e.g.  course  food c o n c e n t r a t i o n , p a r t i c u l a r l y  containers of different to  an a s s u m p t i o n  chosen water  mesh lids  surface. for  the  processing  66  F i g u r e 7.  A comparison of Daphnia.rosea f i l t e r i n g r a t e s measured i n two d i f f e r e n t kinds of container.  67  than  the  4.1.2  larger  v o l u m e s , and  Zooplankton  was,  remained  caught  I  did  how  and  effective  whether  my  non  i n mouthparts,  duplicate  experiments  method  ingested  o r on  i n w h i c h one  to feed i n non-radioactive food f o r  having  grazed  was  given  feeding. two  no No  background  by B u r n s ,  1969).  postfeed.  A l l  The  was  carried  immersion  in alcohol  chloroform)  readings.  steps. i t was  food body,  s e t of animals 5  minutes  after  (This i s a  group  of  animals  were r i n s e d  observed  was  after  between  the  possible  by a d s o r p t i o n * a b s o r p t i o n , i n a d e q u a t e  e t c . , I always  negligible,  radioactive  N e v e r t h e l e s s , t o measure  washing,  and  other  zooplankton  difference  (Figure 8 ).  counts caused  experimental  zooplankton  i n r a d i o a c t i v e food f o r 5 minutes.  measurable  treatments  of  o t h e r p a r t s of the  allowed  t e c h n i g u e used  handling.  Rinsing  To d e t e r m i n e rinsing  minimum z o o p l a n k t o n  a group  Whenever  s u b t r a c t e d from  of f r e s h l y  zooplankton this  through  background  zooplankton  killed  was  (by the not  radioactivity  68  i.o-  a Holopedium gibberum  o  O 5 minute rodioactive feed, followed by 5 minute non-rGdioactive^feed  >  © 5 minute radioactive feed only  <= 0 . 5 LU <  cr  o  cc LLI  h-  00  0.5 FOOD  F i g u r e 8.  CONCENTRATION  1.0 (ug/ml)  R e s u l t s of using a n o n - r a d i o a c t i v e "post" feed to ensure adequate r i n s i n g of r a d i o a c t i v e p a r t i c l e s from f e e d i n g appendages.  69  4-  3 Kind As  Of  previously  of f i l t e r  feeders  mechanism. seston  Food discussed,  the  t e d i o u s and  process  food  be  cultured in sufficient  be d i l u t e d  in filtered  needed,  thus  through  time consuming,  source  o f an  s e l e c t i o n on a  size  for concentrating  alternative easily  food  seems t o o p e r a t e  Since  was  any  I  appropriate  lakewater t o  eliminating  give  the  the  need  selection  to  size  concentration  part  natural  tried cell  the  lake  find that  an  could  that i t could concentrations  for  mechanical  concentration. To  test  the  substance, filtering with  I  suitabilitj began  of  3 2  were i d e n t i c a l . thus should  in  of the  these  nature  experiments  less  of  critical  factor  transported The  i t  to  and  be  r e s u l t s of  due  to  the  Chlorella was  compare  field these  rates  in  both  conditions, including  was  simply The  seston  large  tracer  food  in  filtering  rate  i n some manner t o d i f f e r e n c e s  processed  since  from the  was  Differences  filtrate.,  filtrate  water had  be  food, -  resuspended i n lake instead  experiments  A l l experimental  measurements the  of  P - l a b e l l e d yeast  experiments.  t i m e o f day,  series  possible  c u l t u r e d l a b o r a t o r y Chlore11a a g a i n s t  r a t e s on  lake seston.  sets  a  o f C h l o r e 1 1 a as a  use  easy t o use  in  centrifuged, rinsed  and  of  lake f i l t r a t e  concentrate for  each  volumes  i n any  very  of  alone  meant t h a t  much  experiment water  had  -  a  to  be  case.  comparisons are  shown i n F i g u r e s  9,  DAPHNIA  ROSEA  FOOD CONCENTRATION F i g u r e 9.  ( u g / m l dry wt)  Comparison of Daphnia rosea f i l t e r i n g r a t e s measured with seston and with C h l o r e l l a . ( O  - seston;  @  - Chlorella)  71  10,  11  and 12.  that  replicate  Chlorella seston  variation  than  with  particle  beaker  to  filtering  t h e most s t r i k i n g  size  generally  seston  f o r food,  Or  perhaps  were  natural seston.  for  e x a m p l e showed  Chlorella they  that  available  The two s m a l l e r s i z e s filtering  to  though  that  them a s f o o d  part  of  and  was l e s s t h a n  two s i z e s were i n f a c t  taken  i t i s quite possible that  the  amount  of  material  too  Holopedium and C e r i o d a p h n i a consistent and  with  were rates.  of  differences  Chlorella  sometimes  .  large  between  The  in  supply.  the  smaller  Chlorella  Daphnia  puj.ex  than f o r  I n other seston  words  actually  i n d i c a t e d by t h e d r y pulex  for  from a very e u t r o p h i c  lake  seston  fair  to  there  Filtering  higher,  the  from  food  rates f o r seston  weight c o n c e n t r a t i o n o f t h e s e s t o n . these  only  a t t h e same c o n c e n t r a t i o n by w e i g h t .  behaved a s  with  variation  by d i f f e r e n c e s between p u r e  higher  was  p o s s i b l y because t h e  i s g r e a t e r f o r a non u n i f o r m  affected  and  smaller  individual  Generally the r e s u l t s i n d i c a t e d animals  much  s p e c t r a may n o t have been i d e n t i c a l  beaker.  efficiency  was  feature of the results  Daphnia  contained  be h a n d l e d were  results  as food., F o r  noticeable obtained  r a t e s measured  sometimes lower than  a  but  with  not  seston  with  Chlorella  seston  filtering  72  DAPHNIA  PULEX  FOOD CONCENTRATION F i g u r e 10.  (yug / ml. dry wt)  Comparison of Daphnia pulex f i l t e r i n g r a t e s measured with seston and with C h l o r e l l a . ( O seston; Q - C h l o r e l l a ) -  73  Figure 11.  Comparison of Ceriodaphnia f i l t e r i n g r a t e s measured with seston and with C h l o r e l l a . ( O - seston; & - C h l o r e l l a )  H0LQPED1UM  0  5  G1BBERUM  10  FOOD CONCENTRATION  F i g u r e 12.  (5/jg  dry  15  wt)  20  (yug/ml dry wt)  Comparison of Holopedium gibberum f i l t e r i n g measured with seston and with C h l o r e l l a . ( O - seston; 9 - Chlorella)  rates  75  4. 1. 4 B a d i o a c t i v e In  order  closely in  Yeast  t o measure f e e d i n g r e s p o n s e s  as p o s s i b l e approximating  their  labelled  own  environment,  yeast t o the  concentration counting  still  most! o f  measurements  of  (Burns,  1969;  Lampert,  1974).  medium.  had  be  did  very  the  (0.12  to  tracer  ensure  good  the e n t i r e food  MacHahon  researchers  by  14).  The  concentration good  curves. had  counting  r a t e s measured w i t h  the  1965;  1973;  Haney,  natural seston  6000 c e l l s / m l with  600  use, of  of  the  two: y e a s t  the with  cells/ml  animals  higher the  I  hot  dosage i s about the  with  statistics.  I c h o s e an i n t e r m e d i a t e y e a s t  Bigler,  yeast I should  the o t h e r  variability;  the r a d i o a c t i v i t y  supply  same  s e s t o n c o n c e n t r a t i o n used  Besults  less  with  used  cells.  with  first  weight as the l o w e s t  fi  (Crowley,  of labelled  w e i g h t ) and  tracer  the a u t h o r s have  measuring f e e d i n g c u r v e s  13, and  response  for  feeding,  1965;  a few  ug/ml d r y  concentration  low  the  radioactive  have l a b e l l e d  HacHahon, Only  on  e x t r e m e e x p e r i m e n t s - one  (see F i g u r e s  the  a minimum amount  sufficient  literature  d e t e r m i n e what l e v e l  amount  zooplankton  However,  small a d d i t i o n s of r a d i o a c t i v e  a few  yeast  to  zooplankton  have t r i e d  To  by  I wanted t o add  feeding  m o n o c u l t u r e s f o r f o o d and  and  found  as  statistics.  In  1971)  those  under c o n d i t i o n s  for  yeast  low  yeast  was  somewhat  Otherwise the  filtering  c o n c e n t r a t i o n s were  dosage l e v e l  of  2000  similar. cells/ml  76  _J 0^  n  0  r  I  FOOD  Figure  13.  —  , 2  CONCENTRATION  ,  -  3  (ug/ml  ,  i  4  dry  1 5  weight)  F i l t e r i n g r a t e s of Daphnia rosea measured with d i f f e r e n t amounts of radioactive yeast. ( A - 600 c e l l s / m l . ; O - 6000 c e l l s / m l . )  77  5  FOOD CONCENTRATION  F i g u r e 14.  ( ml A u g / hr)  F i l t e r i n g r a t e s of Holopedium gibberum measured w i t h d i f f e r e n t amounts of radioactive yeast. ( A - 600 c e l l s / m l , O - 6000 c e l l s / m l )  78  for  the  remaining  l e s s than the (1967)  experiments.  concentration  observed  T h i s i s an  below  filtering  order  which  rates  of  of  Burns  IK  magnitude  and  Rigler  to  remain  Rosea  constant.  4.1.5  L e n g t h Of In t h i s  Grazing  type  radioactive  of  Time  experiment,  grazing  i t  periods  be  radioactive feces are eliminated. vary  with  species  measurements  of  and  body  t o be  acceptable  radioactive  results  shown i n F i g u r e  4-1.6  are  Acclimation  The holding  first the  To  of these  vessels  of f r e s h l y containing  maintained  grazing  in  the  before  any  passage t i m e s  made for  time  time p e r i o d .  can  series  e a c h new  determine  type  of  i t  an  for  Representative  .  Food  Concentration  examined  measurement  the  of  effect  feeding  Diaptomns o r e g o n e n s i s  regularly  controlled  that  of  laboratory for various lengths  and  collected  I  to  experiments  a n i m a l s i n the  gut  uptake  Experimental  t i m e between c o l l e c t i o n Groups  Since  t e s t e d , i n order  15  important  terminated  size,  radioactivity  zooplankton  is  refreshed  environment  lake chambers.,  of  rates.  were p u t water (The  in and  lake  1.0  TIME  F i g u r e 15.  (minutes)  R a d i o a c t i v i t y of animals as a f u n c t i o n of feeding time.  80  water  from which  0.75  ug/ml  t h e a n i m a l s were  (ash f r e e dry  r a n g i n g from response  weight)  collected  of sestons) A f t e r  1 t o 5 d a y s , a n i m a l s were measurements.  taken  Immediately  measurements t h e y were a l l o w e d 2 h o u r s food  concentration  experiments s o any  at  which  they  endogenous d i e l  effects  because  16 shows t h e r e s u l t i n g  given  interval  the over  Filtering increased  functional which  A  rates,  be measured.,  All  (early evening), minimal.  rates,  plotted  section  10  over 5  second  results  of f e e d i n g  One  group  to  in  this  magnitude  and  have o c c u r r e d d u r i n g t h e  concentrations,  at  filtering  low  food  laboratory.  For the  r a t e s i n c r e a s e d by  lowest  a factor  of  days. examined  different  was  held  1 ug/ml ash f r e e d r y  concentrated  rates  especially  experiment  under  as  the  5 d a y s between c o l l e c t i o n  about  the  w i t h the l e n g t h o f time i n the l a b .  zooplankton  rate.  this  rates instead  response  these  t h e a n i m a l s were k e p t i n  concentration*  more t h a n  for  filtering  to to  I t i s o b v i o u s t h a t l a r g e changes i n t h e  of  food  as  filtering (In  functional  acclimate  would  about  intervals  some o f t h e d e t a i l s a r e more c l e a r l y v i s i b l e  format.) shape  to  s h o u l d have been  f u n c t i o n s of food c o n c e n t r a t i o n . be  for  prior  were done a t t h e same t i m e o f day  Figure  will  contained  about  5  effects  food regimes. and  of  Animals  measurement  of  i n untreated lake  weight),  another  times normal  in  holding were  held  filtering  water lake  (seston water  s e s t o n c o n t e n t , and  a  81  A  0.25  Diaptomus  0.20-  oregonensis  •  Holding  time = I day  o  Holding time = 3 days  •  Holding time = 5 days  0.15-  0.10UJ  h<t rr  o z S 0.05h-  0 0  1 FOOD  F i g u r e 16.  2  3  4  CONCENTRATION ( ug./ml. dry weight) E f f e c t of h o l d i n g zooplankton i n the l a b o r a t o r y f o r v a r i o u s lengths of time between c o l l e c t i o n and measurement of feeding r a t e s .  82  third  group i n very  acclimated  for  water w i t h rates  to  food  be  oregonensis.  had  feeding  The  last  filtering  of  rates  for  at  at  which  17  and  Holopedium held  low  lake  food  measured  5 food  concentrations.,  each  concentration  their  filtering  zooplankton rates  concentration. of f o o d For  19  effect  considerable  At  acclimation, point there  on low  effect.  h i g h ; i t decreased and was  than  for  the  shows f i l t e r i n g  by by  a l s o an  21  of  animals  were  their  eventual At  various  from each group corresponding  rates  The  r a t e was  one  a b o u t one  third  half  inhibition  after  food  times.  however*  filtering  and  r a t e s as a f u n c t i o n  concentrations  about  were  hours, a c c l i m a t i o n time  filtering  food  pnlex  t o 48 h o u r s . taken  how  different  ( i . e . at  for four acclimation  periods exceeding  concentrations.  and  food d e n s i t i e s  Daphnia  Groups  were  measured  Figure  concentration  appreciable  of  o f measurement) f o r up  intervals  the  a c c l i m a t i o n experiments demonstrated  rates  time  18 show  water.,  Filtering  concentration  lake  filtering  concentrations  concentrations.  at  were  qibberum  i n high  acclimation to  at  animals  experiment, i n  a f f e c t e d by  held  r a t e was  my  to the  Figures  Animals  i n untreated  Again,  concentration  rate curves  Diaptomus  animals held  prior  measured.  filtering  lower  lake water.  2 hours just  t h e same  were  resulting  dilute  at  of f i l t e r i n g  high  there  4  no food  was  initially  after 21  had  hours  a very of  hours.  At  this  rate  at  the  83  Iv5  FOOD Figure 1 7 .  CONCENTRATION  (ug/ml  dry weight)  E f f e c t o f h o l d i n g zooplankton under d i f f e r e n t food regimes before measuring f u n c t i o n a l responses.  Diaptomus oregonensis 9 untreated lake water (0.9 ug/ml)  T  0  1  2  i  FOOD C O N C E N T R A T I O N  e 18.  1  3  :  4  r-  5  ( u g / m l . dry weight)  E f f e c t o f h o l d i n g zooplankton under d i f f e r e n t food regimes b e f o r e measuring f u n c t i o n a l responses.  HiQ  C  H CD  2.0-4  Daphnia W Hi Hi  l-i DJ  rt  0 O n> cn fD o • D rt r+ i-( o tu rt Mi MO  DJ  o  CO Q y-> O H-  I hr.  cn  O  C rt H O  CD  & HMl Mi H - Ml I—' fD  rt 1-1 (D fD  21 hr. acclimation  o  4 8 hr. a c c l i m a t i o n  e  c a  1.0-4  DJ  DJ  acclimation  4 hr. acclimation  1.5-  3  3 rt ro H -  pulex  LLI  r<  rr CD  z rr  0.5H  H H- rt  U3 Mi O O  Ch  0  8  0  FOOD  CONCENTRATION  ( u g . / m l . dry weight )  86  lowest c o n c e n t r a t i o n . 48 h o u r  The i n h i b i t i o n  measurement, and f i l t e r i n g  then d i s a p p e a r e d f o r the  rates  were s i m i l a r  to the 4  h o u r c u r v e , e x c e p t a t h i g h f o o d c o n c e n t r a t i o n s where t h e y higher than the e a r l i e r converted  to  concentration) concentration  curves.  feeding  F i g u r e 20 u s e s t h e same d a t a ,  rates  (by  a n d p l o t t e d t o show how varies  shape.  immediately  Feeding  time..  feeding rates  decreased  however, doubled applied that  For  remained f a i r l y  48 h o u r s .  Feeding changed  rates  the  are  by h a l f  over  at  the  on  at  food  highest  same then  increasing  concentrations, 20  hours  and  i n c r e a s e by  concentrations  20 h o u r s , t h e n  more  than  almost a l l experimental  and  f e e d i n g r a t e s assume  t h e s e c u r v e s s h o u l d be f l a t  the  first,  for a slight  2  l e s s over t h e f i r s t  zooplankton  lowest the f i r s t  constant except  rates  high  have  increase with  three  b e t w e e n 20 a n d 48 h o u r s , work  by  feeding rate a t a given  a l l curves  d e c r e a s e , and e v e n t u a l l y  acclimation  then  multiplying  with t h e l e n g t h o f time t h e animal has t o  acclimate to that concentration* general  were  lines.  implicitly  0.12 Daphnia —©*— 0.25  t -  ,  0  10  pulex  O  ug ml food concentration  ,  :  20  ACCLIMATION  TIME  A  ,  r~  30  40  (hours)  F i g u r e 20 . Same e x p e r i m e n t a s F i g u r e 19 , p l o t t e d t o show how f e e d i n g r a t e a t a g i v e n c o n c e n t r a t i o n v a r i e s w i t h l e n g t h o f time the animal has t o a c c l i m a t e t o t h a t c o n c e n t r a t i o n .  88  tt. 2 F u n c t i o n a l R e s p o n s e For  purposes of comparing  "standard" feeding  experimental  24-28  hours  methods  allowed  was  The  took  temperature, although  measured  a n i m a l s were  at  the  a r e shown i n F i g u r e s lakes.  All  saturating but  there  In with  a  observed  no  variety  food  3 ) , and  experimental explicitly  composition  was  with  used. the  food  allowed  may  2-  to  a l s o have  Feeding  rates  water.from which  the  21(a  - p).  of  They r e p r e s e n t  feeding with  rates  8 species  measured  i n c r e a s i n g food  mathematical  measurements from  showed  a  concentration,  expresion  which  best  results. I tried of  because functional  cases  to  same p h y s i c a l  array o f f u n c t i o n a l response  single  t h i s study  rate curves some  sets  a l l the  considered  the  i n Chapter  temperature of  relationship was  described  using  collected.  Results of t h i s  6  possible  t h i n g t h a t was  varied, since natural lake seston were  e s t a b l i s h e d . , a l l such  (radioactive feeding generally  acclimation  only  of  the  (as d e s c r i b e d  for  a set  after  hours a f t e r c o l l e c t i o n ) ,  concentrations. vary  c o n d i t i o n s was  were c o l l e c t e d  a p p a r a t u s and 3  f u n c t i o n a l responses,  e x p e r i m e n t s were done a s s o o n a s  zooplankton place  Results  to  f i t the f u n c t i o n a l response  curves. i t  did  A not  responses.  rectilinear seem The  i n d i c a t e d that a sigmoid appropriate,  but  not  model  appropriate shapes of the  feeding response  a threshold  data  was for  not the  filtering was  feeding curve  in as  89  Figure  21 (a) - (p). "Standard" f u n c t i o n a l responses measured f o r s e v e r a l s p e c i e s . Feeding r a t e s are i n u n i t s of ug. food i n g e s t e d (ash f r e e dry weight)/ug. zooplankton (dry weight)/hour. Food c o n c e n t r a t i o n s are expressed as ug/ml ash f r e e dry weight.  90  F i g u r e 21(a) 0.2 i  Cn  .£  :  :  =  •  —  —  —  0. I  FOOD  CONCENTRATION  (jug./ml.)  1  F i g u r e 21(b)  0.2  DAPHNIA  ROSEA  15° C. - Loon  L.  \ c o  O  c Q. O O N  CT)  DAPHNIA  \ "CJ  ROSEA  15 ° C. - Loon L.  o  H—  in  cu Cn c  o  Cn  0 LU h-  O O  o  0.2 DAPHNIA  cc  ROSEA  1 5 ° - L o o n L.  CD  O  O  -—-—"—'  Q UJ LU Lu  O  .  0 0  25 FOOD  CONCENTRATION  (jug./ml.)  F i g u r e 21(c) 0.3  DAPHNIA  ROSEA  o  2 0 ° C. - Placid L.  o o 0  DAPHNIA 20  ROSEA  ° C . •- Katherine L.  .  ._  —  f  t  o o _  .  o  O O 0 0  10  FOOD  CONCENTRATION  20  30  (jug./ml.)  93  Figure  21(d)  0.12 DAPHNIA  PULEX  10° C. - U.B.C. Pond  o  8 ortTo  o  o  o  o  o  0 0.12 DAPHNIA PULEX 10° C. - U.B.C. Pond o  X c o  -o-  c  Cn  0  j6o®  _CJ CL O O N  O  Q  0 0.1 2 DAPHNIA  \ "O  PULEX  10° C. - U.B.C. Pond  QJ  Cn  c  -Cn  LU K  0 0.1 2  O  ft  o o o  CD  3  o  LU LU  0  O  / DAPHNIA PULEX  0  10° C. - U.B.C. Pond  %'§' 0  10  5 FOOD  CONCENTRATION  (jug./ml.)  94  95  Figure 21(f)  0.2  o  DAPHNIA o  PULEX  Clone 2  13° C. - Rock L.  O  -©-  o o  O  DAPHNIA  PULEX  I 3 ° C . - Rock  Clone 2  L.  -c \  c o  8  O .D O  c Q. O O  N  0 0.2  oS  DAPHNIA  \ "D OJ f— CO OJ CD  PULEX  13° C - Rock o o  c  Lu  0  AT  D)  0.2  f  • DAPHNIA  CD oo  cl  LU LU  L.  ry  cc  Q  Clone 2.  PULEX  Clone 2  13° C. - Rock L.  O  u  U_  8 0 0  35 FOOD  CONCENTRATION  (jug/ml)  96  Figure  0.125  21(g)  -c \  b o N CJ)  DAPHNIA  •3 CD CO CU  Cn  c  ^  PULEX  19° C. - U.B.C. Pond 0 0.125  UJ K  DAPHNIA  CC  19° C.  PULEX  CD —  Q LU LU LL  0  O  -  V 25  0 FOOD  CONCENTRATION  (jug/ml)  Figure  21(h)  0.3 DAPHN'IA  -O-  -o-  PULEX  20° C. - Deer L  \  o  cD Q. O O N  Cn  0 0.3  \  DAPHNIA  "O CD  o  (/>  PULEX  2 0 ° C. - Deer  L.  <D Cn  c  Cn x  —  UJ  0  <c 0 cc 0.3  O  CD  DAPHNIA  PULEX  20 ° C. - Deer L.  Q Lu LU U_  / 0  °  0  25  FOOD  CONCENTRATION  (jug/ml.)  98 O  Figure 2 1 ( i )  0.2 /  o  3 o  DIAPTOMUS  /  TYRELLI  I 2 ° C - Eunice  L.  ~0~  O  o .o  DIAPTOMUS  TYRELLI  15° C - Eunice L.  DIAPTOMUS  TYRELLI  15° - Eunice  L.  Lu  s.  DIAPTOMUS  0  TYRELLI  19° C - Eunice Q  L.  o  Lu  Uj  0 0  4  FOOD  CONCENTRATION  8  12 (jug/ml)  6  Figure 2 1 ( j )  0.25  O o  O DIAPTOMUS  8° C. - Eunice L .  \  c o 0 c 0.25 O O N  DIAPTOMUS  Cn  \  KENAI  KENAI  8° C. - E u n i c e  R  L.  •o cu CO OJ  c  Cn  UJ h-  @-  •©  Cn  0  10  0  20  0.25  CC 0  CD Q LU LU U.  •  o o  o  DIAPTOMUS 1 2 ° C. -  KENAI E u n i c e L.  0 10  0 FOOD  CONCENTRATION  (/Ug./ml.)  F i g u r e 21.(k)  0.075  T5  O  o DIAPTOMUS 15° C -  KENAI  Eunice  L.  0 ^  0.075  c o c _o  "3.  DIAPTOMUS  o  15° C. -  KENAI Eunice  L.  CD  Co C D  OJ CJ)  O  0  ~i—  5  0  c  15  10  Oi  ^  0.075  Lu h-  §  DIAPTOMUS  CD  KENAI  ' 19°C.-.Eunice  Q LU UJ U.  L.  0  loo  00  5 FOOD  CONCEN  10 TRA TION  15 (/ug/ml)  101  F i g u r e .21.(1)  o:3  0 CERIODAPHNIA 15° C. -  0 0.3  f  SP  Loon  L.  o  0  8  o  O  \ c o o  c o  9/  CL  o o N  D>  /  CERIODAPHNIA  SP  15° C. - L o o n  L.  CERIODAPHNIA  SP  0 0.25  \  "O CD  19° C. - U.B.C. Pond  CO CD CD  c  CERIODAPHNIA 19° C. -  SP  U. B.C. Pond  25 FOOD  CONCENTRATION  (jug./ml.  )  FOOD  CONCENTRATION  (jug./ml.)  103  F i g u r e 21(n) 0.08 DIAPHAN0S0MA  BRACHYURUM  1 5 ° C - Eunice L . \-  c o -+—  o  0.04  O O  c o  CL  Lu  O  o o  0  N  CDO.08  cc CD  N  OO  •:  DIAPHANOSOMA  1 5 ° C - Eunice L .  CO OJ  Q Lu Lu LU  BRACHYURUM  OJ  c? 0.04 1  ©°  3 0 0 .  8 FOOD  CONCENTRATION  16  (ug/ml)  105  F i g u r e 21 (p) 0.2 HOLOPEDIUM GIBBERUM 14° C -  Eunice  o  L.  O.N o ^  -  ^  ^  o  -c  0 c 0.2 CL  HOLOPEDIUM  O O N  GIBBERUM  14° C - Eunice  Cn  L.  0.1 -  \  "O CD  to CU  Oi C  0o> =5 0 . 2 -  u  LU  h0  cc CD  O.J -  7o o  Q  HOLOPEDIUM GIBBERUM  LU LU  15° C - Placid  LL  L.  020  10  0 FOOD  CONCENTRATION  Lug /  ml)  106  suggested  by  considered  Parsons  in  this  model, a n d t h e P u j i i or  et  a l .  study  special  were  function.  not i n shape, but they  The  three  the d i s c equation, the Heal  The l a t t e r two c a n be  both  UBC Computer C e n t r e fitting  include the disc  each  of  squares  was used equations  of a user s p e c i f i e d  stepwise  equation as a  selected  program  UBC  BHDX85  function  (1),(7),and  t o data  least  values  by  squares  means  of  giving  the  best f i t to a s e t of data  was  r e s i d u a l mean s q u a r e s  Each o f e q u a t i o n s  t o be c o n s i s t e n t l y b e s t  f o r a l l the sets  n o t even w e l l d e f i n e d subsets; o f data  curves f o r  one  function./  Some  under c e r t a i n summarizes  species)  of the three  ( 1 ) , ( 7 ) , and (8) p r o v i d e d  t h e b e s t f i t f o r some s e t s o f d a t a , b u t no s i n g l e  corresponded  to  function  of  conditions,  these  but  results.  by a d i s c  not 70%  under of  a  single  or Hichaelis-Henten  by some f o r m  o f type  best  f i t by a R e a l o r F u j i i for a l l practical  purposes  curves  (type  I I I response. function,  others.  the  data.  was In  (e.g. a l l f e e d i n g  s p e c i e s f o r example showed s i g m o i d  30%  that  the  (8) t o t h e measured  o b t a i n s a weighted  function  by c o m p a r i n g f i n a l  functions tried.  described  from  Gauss-Newton i t e r a t i o n s on t h e p a r a m e t e r s .  The  fact,  sigmoid  t o o b t a i n parameter e s t i m a t e s f o r  f e e d i n g c u r v e s . . T h i s program  found  models  case.  A non-linear least  fit  (1967).  II)  "best"  responses Table were  II best  response,  Some o f t h e r e s p o n s e s had  reduced  parameter  values  these equations t o a  TABLE fl. P a r a m e t e r e s t i m a t e s o b t a i n e d b y f i t t i n g e q u a t i o n s ( 1 ) , (7) a n d (8) t o t h e m e a s u r e d f e e d i n g c u r v e s . V i s i n u n i t s o f ug d r y w e i g h t i n g e s t e d / u g d r y w e i g h t o f o o l a n k t o n / h o u r . k, G a r e i n J ^ o ug d r y w e i g h t s e s t o n / m l . EMS i s e r r o r mean s q u a r e , b l a n k e n t r i e s i n d i c a t e t h a t t h e non l i n e a r l e a s t 2  P  squares procedure d i d not converge.  Temp °c  Species  ni=n E a u a t i o n V  k  (equ. 1) EMS  V  G  n  ( e q u . 7) EMS  Fujii V  Eq nation  k  (equ.  c  i)t EMS  10  0.042  0. 09  .0003  0. 047  0.26  0.4 3  .000328  0.042  0. 093 -0.007  0.000330  ti  10  0.040  0.3  .000274  0. 044  0.40  0.80  .000313  0.040  0.30  -0.004  0.000313  ii  10  0. 037  0.50  . 000059.  0. 04  0.81  0.80  .000064  0.037  0.58  -0.000005  0.000065  10  0.10  1. 62 .000465  0. 092  1.28  1.32  .000497  0.10  1. 62  0. 0008 '  0.000505  H  13  0.07  0.42  .000125  0. 067  0.19  1.85  .000122  0. 067  0.59  0.73  0.000121  n  13  0.063  0.30  .000189  0.059  0. 012  3 .84 .000193  0. 061  1.4 9  3.79  0. 0 0 0 1 7 5  ti  13  0. 066  0.64  .000535  0. 06  0.036  4.49  .000538  0.080  0. 95  -0.078  0.000563  it  13  0.10  1. 41 .000564  "  13  0.094  0.33  .00193S  0. 087  0. 016  3.66  .002014  0.118  0.57  -0.115  0.001983  ei  13  0.057  0.20  .000210  0.053  0. 011  3.88  .000212  0.059  0.3 0  -0.057  0.000227  13  0.068  0.79  .000172  0.065  0.8 7  2.30  . 000131  0.068  0.79  ti  13  0.096  0. 40 .000557  0. 091  .0. 089  2 .69 .000444  0.105  0.48  it  19  0.186  14.44  .000048  0.186  14.45  .19  0.045  0.80  .000031  0. 045  0.80  -0.0000035  ti  20  0.2 9  8.87  . 0072  1.71  ti  20  0.26  2.81  . 00020  0.195  ti  20 .  0. 08  0.74  . 0035  "  20  0.27  1.79  . 0011  Daphnia  pulex  II  II  i'  !  Real Equation  0.0 -0.076 0.00002  0.000186 0.000587 0.000055 0.000036  0.54  . 0081  0.29  8.87  0.0000001  0.0082  1. 93  1.59  .00013  0.259  2.81  0.00005  0.000233  0. 084  0. 92  0.76  . 0040  0.238  1.4 4  1.26  .0012  0.27  1.79  0.000002  0. 0012  37.8  TABLE I I .  (cont'd.)  Temp  °C  Species  Disc  Eauation  V  k  (equ. EMS  Fujii  R e a l E q u a t i o n ( e q u . 7)  1) V  G  n  EMS  V  (equ.  Equation k  8)  c  EMS  14  0.125  2 . 63  000170  0. 157  3.30  0.7 4 .000175  0. 109  2 .50  o . 11  0. 0 0 0 1 8 2  14  0. 048  0.178  .000108  0. 042  0.002  3.30  0. 043  0.4 9  5. 00  0. 000082  15  0.10  2 . 97  . 0028  0. 086  14.44  15  0.064  1.30  . 001.65  0. 065  1.32  15  0.065  1.73  .000085  0. 065  1.73  0. 000026  0. 000097  15  C. 047  0.73  .00137  0. 045  0.75  1.73 .00154  0. 045  1.76  0. 64  0. 00152  It  15  0.13  2 . 98  .00073  0. 158  3.49  0.75  0. 132  2.9 9  II  20  0. 25  12.24  .00106  »  20  0.24  3.78  20  0.13  1.56 . 0011  15  0. 055  0. 003 .00027  0. 055  0. 086  15  0. 025  0 . 97  .00014  0. 025  12  0.35  8 .66  .00031  15  0.047  1.17  .. 0 0 0 0 6 1  15  0.0042  0.144  i\  19  0.0088  1 . 05 . .000014 0. 008  Diaptomus oreqonensis  12  0.29  10.12  .000107  12  0. 082  0.55  .000073  Daphnia  rosea  II  11  il  it  Diaphanosoma  .000080  3. 05 .0029 0.94 .00193  .00082  0. 25  12.24  0. 13  1.56  0. 0  0. 0012  1.98 .00029  0. 052  1. 047  5. 0  0. 00029  1.19  2 . 90 .00015  0. 055  2 .68  - 0 . 137  0. 00015  tyrelli  21 .25  681.  0.88 . 00032.  1. ?5  73.5  »  0. 043  20.24  2 .88 .000063  0. 043  21. 05  v  •  -1. 6 X 1 0 "  1 0  0. 00116  . 0033  brachyurum  Diaptomus  0. 00083  - 0 . 00039  .000001 0. 039  0. 012 4.1 0. 0 J4  66.6  0.64  0. 00034  0. 57  0. 000064  .000001 .000017  0. 29 0. 085  0. 0028  1. 87 .000080  0. 073  10.12 2.37  - 0 . 0000025 0. 000116 1. 80  0. 000083  TABLE I I . (cont'd.)  Temp °C  Species  Holopedium gibberuir.  8  Disc V  Equation k  0.386  3.80  ( e q u . 1) EMS  .00073  V  R e a l E q u a t i o n ( e q u . 7) EMS n G  2. 54  25.8  0.48  .00040  8 H  II  II  II  it  Diaptomus  kenai  II  II  II  II  II  Ceripdaphnia • » i»  . sp.  Fujii V  0.386  Equation k .  3.80  0.40  100. 0 1. 98  ( e q u . 8) c  EMS  0.0000035  0.00083  0. 58  0.00032  12  0.22  1. 98  . 0020  0. 183  1.37  1.21  .00217  0.22  12  0.205  0.81  .00117  0.166  0.35  1.81  .00115  4.17  14  0.106  7.14  .00055  0.15  7.14  0.99  .00056  0.119  14  0. 03  0.056 . 0004 2  0.033  0. 001  3.48  .00038  4.17  15  0.18  2.08  .00099  0.148  3.33  2. 64  .00102  0.15  5 .39  0.78  0.00097  8  0.287  6.81  .00157  0.287  6 .81  0.000001  0.0018  8  0. 041 2. 98  .00001  0.023  0.79  2.53  .0000003 0. 023  6.32.  1.56  0. 0000002  12  0.074  1.17  .00007  0.063  0.68  1.58  .00007  0. 074  1.17  0.00015  0.00007  14  0. 097  6.19  .00007  0.065  2.84  .00003  14  0. 016 1.34  .000011  0. 010  0. 012 • 7.3.5  . 000010  0. 016  1.34  0.00066  0.000012  19  0.016  0.2 4  .000042  0.015  0. 047  2.55  .000043  0. 015  0.75  2. 92  0. 0 0 0 0 4 3  15  0.108  0.96  .00723  0.100  0.84  1.47  .00839  15  0.365  6.76  .000778  19  0. 053 0.41  0. 002  0.3 5  1.19  .00018  19  0. 35  4.10  .00016  10.. 9  21.2 5.79 23.1  -0.00000008 0.0022 -0.44 0.088 -1.38  0.00102 0.00056 0. 00022  110  disc  eguation. V a l u e s f o r maximum f e e d i n g r a t e V were t h o s e  fitting  a  disc  eguation  f u n c t i o n a l responses. were o b t a i n e d equations  by  near  measuring the  zooplankton.  "high and  a, 30  low show  species. in  or  the  the  feeding  d e f i n e any  "high  V,  low  same  data  tyreHi) increasing  of  t&  - 27  a"  groups. by  give  a graphical 6  species  Figures lake  "a" disc  of points  into  28,  29  instead of  d i f f e r e n c e from l a k e t o  can  of  represented  F i g u r e s 31,  32  maximum  but  feeding  temperature, had  and  rates that  36 show maximum f i l t e r i n g  as and  maximum f e e d i n g r a t e s  (8 - 20  domes,  be  °G)  was  within  not  by  lake  that  rates two  that;  species  increased.  33  show The  tt  enough  range, and  Diaptomus  declined  Figures  34,  to  three  with  ( Daphnia pulex  rate plotted against  r e l a t i o n s h i p i s apparent.  dome-  "V .  great  Holopedium qibberum, Diaptomus k e n a i  had  rate  fitted  e  clear division  temperature.  range covered  Daphnia rosea)  clear  22  grouped  processes  complete (  determined  p a r a m e t e r s found f o r no  temperature v a r i a t i o n  temperature  of  by  "a".  functions  species  Figures  is  Most b i o l o g i c a l shaped  slope  T h e r e i s e s s e n t i a l l y no  the parameter  experimentally  o f maximum f i l t e r i n g  the  origin.  There  V",  the  Estimates  r e p r e s e n t a t i o n of the of  to  obtained  35  temperature;  and and no  f  0.3 O  DAPHNIA  ROSEA  0.2 1  0.  o o  O  D  o  00 o  0 0  0.1 MAXIMUM  F i g u r e 22.  INGESTION  0.2 RATE  " v " . ( j u g / / j g / hr)  I n i t i a l s l o p e "a" of f u n c t i o n a l response v s . maximum .feeding r a t e "V" f o r Daphnia rosea.  MAX.  FILTERING o  H-  H CD ro  c CD  < co •  3  H  3  Hrt p-  pj  0)  3  co  3  O  Hi  X  t)  CD CD Ch H-  m co H  o  CD =  (a  =  >•  O  m  C  <  Ml pJ Ml rt CD  ;z  CD  3  Q = rt < H= O  '3  Ml fJJ O M tr a  CD  cu co  V o H - CO OJ CD  ZTT  RATE  ( ml / jug / hr)  =1  DIAPTOMUS LU I<  KENAI  0.2  rr (3 cc  LU  0. O  O O  X  <  O  0  O  O  0.2  0.  0 MAXIMUM F i g u r e 24.  INGESTION  RATE  "v"  (jug ./jug/hr )  I n i t i a l slope "a" of f u n c t i o n a l response v s . maximum feeding r a t e "V" f o r Diaptomus kenai.  0.3  0.3  \  CP  £  CERIODAPHNIA  LxJ  < CC  .  CD  O  ZZ.  cc  LU  SP  0.2  O  0.1  O  1— _|  O  \L X  <  0 0  0.1 MAXIMUM F i g u r e 25.  INGESTION  0.2 RATE  " V "  0.3 (/jg  / jug /  hr)  I n i t i a l slope "a" of f u n c t i o n a l response v s . maximum feeding r a t e "V" f o r Ceriodaphnia.  o  HOLOPEDIUM  GIBBERUM  O  o  0 c e  3  5  MAXIMUM  F i g u r e 26.  °  T  1  0.1  0.2  INGESTION  RATE  " V . " (pq  :  ••  i  0.3 / »q / hr)  I n i t i a l slope "a" of f u n c t i o n a l response v s . maximum feeding r a t e "V" f o r Hoiopedium gibberum.  1  0.4  0.3  0.2  H  DIAPTOMUS  TYRELLI  :0  DIAPTOMUS  OREGONENSIS:  A  A O  0.1 A  o  O  A  O  0 0  0.2  0.1 MAXIMUM F i g u r e 2.7.  INGESTION  RATE  " V"  0.3 ( u g / ug / hr )  I n i t i a l slope "a" of f u n c t i o n a l response v s . maximum feeding r a t e "V" f o r Diaptomus t y r e l l i and Diaptomus oregonensis.  0.5 UBC POND 0.4  LOON  LAKE  •  Daphnia pulex  O Daphnia rosea  O  Ceriodaphnia sp-  O Ceriodaphnia sp.  0.3  0.3  0.2-  0.2  0.  0.1  O  O O  0 0  0.  0.2 MAXIMUM  F i g u r e 28.  0 0.3  0.4  FEEDING  0 RATE  0.  0.2  0.3  V  Feeding parameters of s p e c i e s taken from UBC Pond and Loon Lake.  0.4  DEER •  PLACID  LAKE •  Daphnia pulex  KATHERINE  LAKE  LAKE  Daphnia pulex  Dophnia rosea  O Holopedium gibberum A Diaptomus oregonensis 0.3  0.3H O  0.21  0.21  0.1  O.I  O A  0  0.1  0.2  0.3  0  0  MAXIMUM Figure  29.  0.1  FEEDING  0.2 RATE  0.3  0  0  O.I  V  Feeding parameters of s p e c i e s taken from Deer Lake, P l a c i d Lake and K a t h e r i n e Lake.  0.2  0.3  •  Laboratory-reared Daphnia  EUNICE LAKE •  0.6 H  W  pulex from ROCK LAKE  Holopedium gibberum  A Diaptomus kenai  A  •  O Clone 2, H  Diaptomus tyrelli  O Daphnia rosea  0.5  Clone I, L  A Clone 2, L H= reared on high food cone.  L=  0.4  0.41  0.3  •  0.5-^  Diaphanosoma brachyurum  A  Clone I , H  0.3  1  M  II  ,  low  II  II  o  o  • 0.2  0.2  A  O.I 4  • A  A •  0  ri^A 0  A •  0. A  o  .  D  A *  O.I  •  0 0.3-  0.2  MAXIMUM F i g u r e 30.  0.4  FEEDING  0.2  0.  0  RATE  V  Feeding parameters of s p e c i e s taken from Eunice Lake and Rock Lake.  0.3  0.4  120  0.3  TEMPERATURE Figure  (°C.)  31. Temperature v a r i a t i o n of maximum feeding r a t e s f o r Daphnia rosea and Daphnia pulex.  0.4  H  10  >  12  TEMPERATURE  TEMPERATURE  14 (°C)  (°C)  F i g u r e 32. Temperature v a r i a t i o n of maximum f e e d i n g r a t e s f o r Holopedium gibberum and Diaptomus k e n a i .  122  F i g u r e 33  Temperature v a r i a t i o n of maximum f e e d i n g r a t e s f o r Diaptomus t y r e l l i .  123  UJ I<  rr CD  zz cr: UJ  X  <  TEMPERATURE  (°C)  F i g u r e 34. Temperature v a r i a t i o n of maximum f i l t e r i n g r a t e s f o r Daphnia rosea.  124  0.3  o o  0CD  rr LU _J  o  DAPHNIA PULEX  8  0.2 o  o  -L o  S  CP  ^  3  Q 0.  6b  x <  8  ooo  —  O  O O  0 10  n  ^  TEMPERATURE (°C) F i g u r e 35. Temperature v a r i a t i o n of maximum f i l t e r i n g r a t e s f o r Daphnia pulex.  o 2 10  '  125  A  0 . 5 H  c o  O DIAPTOMUS KENAI A HOLOPEDIUM GIBBERUM  cz _o CL  O  o N  cn =3  UJ <  A  0 . 2 5 -  rr UJ  A  x <  A A O  O O O  0)  0  A  ~~r~ 10  TEMPERATURE  2 0  (°C)  F i g u r e 36. Temperature v a r i a t i o n of maximum f i l t e r i n g r a t e s f o r Diaptomus kenai and Holopedium gibberum. '  126  5 DISCUSSION  5.1  Consistency Before  With O t h e r  discussing  specific  worthwhile comparing the rates  reported  in  the  r e s u l t s are at l e a s t the  same by  others  because  of  the  employed  by  measured only rate  nonetheless it  may  may  low  work  s p e c i e s and  The  Bigler  Host of  on  uncertain  c o n d i t i o n s and r a t e s are  of food  rate"  f o r the c r e d i b i l i t y  with  -  those task, units often  concentration i.e. filtering  Such a c o m p a r i s o n (or l a c k of i t )  other  i n that they  sound (1967)  my for  is  that  f o l l o w i n g paragraphs d i s c u s s  o f a few  comparable  data  here  measurements  and  concentrations).  i n the l i g h t  and  considerable Daphnia .  food  i t is  to check t h a t  a l s o , feeding  f o r s i n g l e values  seem t o use  Burns  other  of t e c h n i q u e s ,  workers,  results.  be c o n s i d e r e d  obtained  i n order  arduous  "maximum f i l t e r i n g  valuable  lend the  present  i s a fairly  reported  f o r very  literature,  variety  ( g e n e r a l l y as  rates  o f ray s t u d y ,  However, c o m p a r i n g ray r e s u l t s w i t h  different  and  feeding  results  consistent with  species.  obtained  Data  the  investigations that deal  with  the  same  techniques. and  the f i l t e r i n g  Burns  (1969)  have  published  r a t e s of s e v e r a l s p e c i e s  t h e i r e x p e r i m e n t s used  3 2  P-labelled  of  yeast  127  as  the  only  filtering dilute  source  the  A  rate  observed  comparison  of  r a t e s a s measured by B u r n s a n d B i g l e r 37-  given  t h e same, t h e r e s u l t s  feeding  a n d most measured t h e maximum  filtering  conditions.  me i s shown i n F i g u r e not  food  rate - i . e . the food  filtering  of  that  r a t e r e s p o n s e i s an a d a p t a b l e  r e s u l t s should  be i d e n t i c a l ,  just  rosea  (1967) a n d  similar.  trait  very  Daphnia  the techniques  a r e remarkably  in  there  used  by were  I f i n fact i s no  comparable  reason  within  the  p h y s i o l o g i c a l c a p a b i l i t i e s o f the animals. Figure plotted  38  with  filtering  shows  B u r n s and  rate  as  a  filtering  r a t e s measured  Rigler»s  (1967)  function  o f body l e n g t h -  Since  as t h e only  ( a t 2-5  measurements were done w i t h 10*  cells/ml),  yeast  i n this  results  on  food  study  maximum their  the comparison i s s u b j e c t t o t h e d i f f i c u l t y  x of  i n t e r p r e t i n g the seston  ash f r e e d r y weight e q u i v a l e n t o f t h i s  yeast  There  concentration-  overlapping  i s  of points, indicating  nevertheless that  considerable  my measurements a r e n o t  inconsistent. Haney's during to  mine  (Table  III)  for  Diaphanosoma  Holopedium qibberum.  filtering than  i n s i t u study  o f ambient f i l t e r i n g  s e v e r a l seasons i n Heart Lake y i e l d e d v a l u e s  guadrangula, and  (1973)  that  Daphnia  brachyurum. Diaptomus  by  comparable Ceriodaphnia oregonensis,  F o r 3 o f t h e 5 s p e c i e s , the range o f  r a t e s measured i n t h i s s t u d y found  rosea.  rates  Haney,  probably  i sconsiderably  larger  b e c a u s e I used a w i d e r  2.0  A  DAPHNIA o  ROSEA  This study.  —6—  T3  Burns a  20°  Body length  Rigler ( 1 9 6 7 ) .  C.  1.28mm. Body length 1.6 mm.  — B u r n s & Rigler ( 1 9 6 7 ) results c o n v e r t e d to rates for 1.28 mm. body length, using their rate - body  LxJ H <  length  filtering  relationship.  rr  C D  rr  LJ f-  _J -332)  10 FOOD Figure  CONCENTRATION 37.  15  20  (ug/ml  25  dry w e i g h t )  Comparison of Daphnia rosea f i l t e r i n g r a t e s measured i n t h i s study with those m e a s u r e d by B u r n s & R i g l e r (1967) .  i  to CO  129  A  0.6  0.8 BODY  Figure  38.  1.0  1.2  LENGTH  1.4  1.8  (mm.)  F i l t e r i n g r a t e s of Daphnia rosea and Daphnia pulex as a f u n c t i o n of body length.  T a b l e I I I . Comparison of f i l t e r i n g r a t e s measured i n t h i s study with those measured by J.F. Haney (1973). Haney (1973) Species  (ml./ind./day)  Daphnia r o s e a C e r i o d a p h n i a quadrangula Diaphanosoma  brachyurum  Diaptomus oregonensis Holopedium  gibberum  T h i s study (ml./ind./day)  High  Low  High  20.8  1.7  25.6  7.7  0.4  4.5  0.05  5.7  0.  5.1  0.02  2.2  0.  19.4  0.5  12.5  0.  119.5  0.1  Low 0.6  131  range of food high  concentrations,  values.  were t e s t e d  My  Ceriodaphnia  over a smaller  were measured a t o n l y smaller  variation  t h e s e two  were s m a l l e r  in filtering  combinations published  rates and  for  Daphnia  concentrations  by C r o w l e y  Haney and H a l l  of  20  °C.  f o r Daphnia  of comparable s i z e  in  grazing have  early  lake  accurately  deal  been  indicating  that  evening).  I  feeding  have  done  and  for  different  tap  identical to  at  s t r a t e g i e s among  rates of  temperatures  cycle  rates  similar would  whose  magnitude some  measurements i f  diel  insufficient species.  food  probably  (my e x p e r i m e n t s  doubt  as  reflect  patterns  vary  as a basis  were  of d i e l  and  t h e n measurements o f f i l t e r i n g are  water,  temperature.  and  these  raises  rate  Furthermore,  among s p e c i e s ,  in  But t h e p o s s i b l e existence  quantified,  these f i l t e r i n g  rates.  pulex  a t 19 - 20 °C  c y c l e s f o r some s p e c i e s ,  not  grazing  study  r a t e s o f 8 - 33 m l / i n d i v i d u a l / d a y f o r  c o r r e s p o n d t o t h e end o f t h e l i g h t done  explain the  (1975) measured d a y t i m e f i l t e r i n g  I found  concentrations,  as  pulex  (1973), a p p e a r t o be a l m o s t  5 - 15 m l . / i n d i v i d u a l / d a y  D. p u l e x  Diaphanosoma  i n this  measured h e r e f o r D. p u l e x a t t h e same  around  My  This could  r a t e s found  and  t h a n Haney*s and  temperature range.  one t e m p e r a t u r e .  low  species.  Filtering  rates  bounded by a r t i f i c i a l l y  timing to  how  overall a  great  rate  such  f o r comparing  132  5.2 T y p e s Of F u n c t i o n a l Response Several of  the  standard  Obtained filter-feeding  models  proved  a d e q u a t e t o d e s c r i b e most o f t h e f u n c t i o n a l r e s p o n s e s measured here, to  b u t no s i n g l e  dilute  food.  individual  I I , but  Part  of this  there  was  indicate  the  d i l u t e food be  highly exact is  to  suggest  literature  characteristics  abounds of  with  experimental  form o f t h e f e e d i n g from  a  responses as w e l l ) .  that  part  with  results,  a r e not capable  seems  to  be  Stewart,  statistically  reject  to frost's  o f i t may  any  of testing  (1972)  Fuglister of  data.  supply.  filter-feeding  fine-scaled  which seem  t o be  food  conditions  p o i n t o f view, b u t p r e s e n t  unacknowleged. and  but  Speculation about the  response i n d i l u t e  theoretical  were  t h e models i n t h e r e g i o n o f  v a r i a b l e f o r low a v a i l a b l e f o o d .  Fuglister  fitted  a few s i g m o i d  responses  o f a c c l i m a t i o n t o changes i n food  the  compared  techniques  the  seemed t o be due t o t e m p e r a t u r e ,  evidence  for  q u a n t i t a t i v e and e v e n  ( i . e . most o f  were  measured  c o n c e n t r a t i o n s a r e g e n e r a l l y much t o o  exciting  often  there  also  responses  showed c o n s i d e r a b l e  variation  a process  models,  functional  variability  Although  to  The  species  some q u a l i t a t i v e Type  model c o n s i s t e n t l y d e s c r i b e d t h e r e s p o n s e  the theory. For  This  example,  point Hullin,  (1975)  could  not  three different  feeding  curves  133  5.3 C o n s t a n c y Of F u n c t i o n a l R e s p o n s e s If that  t h i s study  individual  h a s y i e l d e d any c l e a r functional  responses  v a r i a b l e commodities, changing conditions study  and  of  with  several  species  (at a given  i ti s  temperature,  past  factors.  species,  however,  and  part  was  temperature and  of  the  very  In t h i s  from  similar  variability,  for  a  most  namely  feeding  It  5.3.1  temperature  t h a t maximum f i l t e r i n g  low f o o d  concentrations)  may  of the  of the  r a t e s (or be  quite  i n d e p e n d e n t o f t e m p e r a t u r e , a n d t h e same f o r most o f  species  (see F i g u r e s  34-36).  E f f e c t Of Temperature To  any  appears  r a t e s a t very  constant, the  also  given  The r a n g e  d e p e n d e n c e , may be q u i t e p r e d i c t a b l e a n d c h a r a c t e r i s t i c species.  food  among f u n c t i o n a l r e s p o n s e s  a s t h e r e was among r e s p o n s e s between s p e c i e s .  variation  surely  of f i l t e r - f e e d e r s are  unknown  t h e r e was a s much v a r i a b i l i t y  of a g i v e n lake)  probably  result,  my k n o w l e d g e , t h e r e h a d n o t a p p e a r e d i n t h e l i t e r a t u r e  measurements  rates f o rf i l t e r temperature species,  and  o f temperature feeding  zooplankton.  feeding  of the effect  v a r i a t i o n o f maximum  of  have  been  temperature  feeding  The o n l y r e f e r e n c e s  to  o b s e r v a t i o n s , f o r a few on  maximum  filtering  134  rate  -  or,  equivalently,  on  feeding  rate  at  Ion  food  concentrations. The  temperature  measured  i n t h i s study  classify  the s p e c i e s  of  their  for  Daphnia r o s e a  and  for  tvrelli  feeding  parameters.  temperature  )  (Figures  Maximum  1967;  seemed  filtering  to  temperature.  Daphnia  to  be  tend  cultured.  invariance study,  magna  around to  12 filter  found  of  -  14  This  feeding  to  maxima  to  be  (1968)  found  unaffected  Daphnia rosea  at  by 12  i t s maximum f i l t e r i n g  rate  °C.  that  He  concluded  most r a p i d l y u n d e r c o n d i t i o n s o f  probably  which they explains  o f t h e maximum f i l t e r i n g  because  exception  1964; B u r n s a n d B i g i e r ,  Schindler  t e m p e r a t u r e s i m i l a r t o t h o s e under or  maximum  o f Daphnia  temperature  <1971) . a f t e r r e a r i n g  f o r several generations,  cladocerans  °C,  independent  several species  1969; H a l l *  °C  highest  However,  quite  with  However  of  Kibby  of  increase  1965).  rates  33).  be  rates  and D i a p t o m u s  (with t h e p o s s i b l e  to  rates  20 - 25 °C ( B u r n s , HcBahon,  feeding  a t a r o u n d 20  Diaptomus kenai 31 -  dependence  34-36).  filtering  have been o b s e r v e d  observed  pulex occurred  qibberum.  responses  temperature  Highest  f o ra l l species  pulex  functional  i t might be p o s s i b l e t o  to the  and Daphnia  rates  the  indicated that  a r o u n d 8-12 ° C ( F i g u r e s  Daphnia  around  of  according  Holopedium  filtering of  variation  experiments  rates  were the  collected temperature  measured  in  this  were a l w a y s done a t t h e  135  temperature  of  collected.  I  the am  water  from  which  n o t aware o f any  temperature dependence of f e e d i n g but  Holopedium  classified their  gibberum  as c o l d  water  and  published  r a t e f o r my  species  seasonal pattern  animals  limited (Pennak,  were  measurements on "cold"  Diaptomusoregonensis  geographical distribution The  the  by  species, have  been  temperature  in  1953).  of z o o p l a n k t o n d e n s i t i e s i n t h e UBC  F o r e s t Lakes a l s o i n d i c a t e s that temperature a d a p t a t i o n occurs (Baiters,  p e r s . comm.;  Heiil,  p e r s . comm.). /  Specifically,  d i a p t o m i d s a r e b e l i e v e d t o be a c t i v e a l l w i n t e r . most  abundant  Holopedium and  species  then d e c l i n e  words,  the  populations start  Holopedium  a second  in  remain  s m a l l e r peak their  periods  of  October most  and  do  u n t i l mid-  numerous  peak a t t h e b e g i n n i n g o f A u g u s t end  of  October.  Daphnia  whereas H o l o p e d i u m During  the  contain  summer.  Holopedium  and  Holopedium  tend  to  Hovement  temperature i n c r e a s e s -  descend  In  on t h e o t h e r  throughout  hand,  until the  spring  patterns  to  with  J u l y ; they increase to a  only. i n  kenai  with other  coincide  and r e m a i n a b u n d a n t  eggs  July,  September,  growth  Daphnia  reproduce  Diaptomus  and  time  Diaptomid  November.  rapid  water.  become  rapidly.  low t h r o u g h A u g u s t in  a t which  peak n e a r t h e b e g i n n i n g o f  periods of r e l a t i v e l y c o o l not  spring,  to increase  populations  and  early  They a r e t h e  also  prefer  season,  and  fall.  indicate  cooler  pronounced  that  waters.  c o o l e r waters as the  p. k e n a i e x h i b i t  the  summer  vertical  136  migrations,  but  as  temperatures  increase,  g r e a t e r depths d u r i n g t h e day; i n P l a c i d shallow,  they  actually  they descend t o  Lake, which  i s  very  have a summer d i a p a u s e i n t h e b o t t o m  mud. An  enclosure  Gwendoline cold  a  Holopedium  July,  which  (10,000 1)  large  ( p e r s . comm.)  Holopedium*s  plastic  bag.  temperature  reached  pump k e p t t h e w a t e r  bag Holopedium  t i m e t h e water  persisted  14-15  temperature had f i n a l l y  be  a  reveal  zooplankton temperature  preference, since  w i t h t e m p e r a t u r e , and i t i s t h e  two  rate  net energy some  gain  species  energy i n t a k e  will at  In  a  and c o o l e r . by  14-15 ° C .  rates  cannot  c o m p l e t e l y unambiguous p i c t u r e o f  vary  functions  °C.  reached  dependence o f f e e d i n g  to  week o f  t h e end o f A u g u s t ,  Of c o u r s e t h e t e m p e r a t u r e expected  water  I n the c o n t r o l  circulating  until  in  affinity for  had c o m p l e t e l y d i s a p p e a r e d by t h e t h i r d  bag a s m a l l  this  Heill  E a c h e n c l o s u r e was a c o l u m n o f l a k e  when t h e w a t e r  second In  by  by  further illustrates  temperatures.  enclosed bag  Lake  experiment  metabolic rates  difference  between  also the  t h a t determines t h e temperature a t which be maximal.  However, i t seems  l e a s t t h e maximum  occur a t  about  the  that  for  r a t e s f o r f e e d i n g and n e t same  temperature  (Green,  1975). From  a  statistical  viewpoint,  one  might  be s k e p t i c a l  a b o u t my o b s e r v a t i o n o f t e m p e r a t u r e  independence  filtering  v a l u e s were o b t a i n e d f r o m  rates,  because t h e l a t t e r  of  maximum  137  the  slope  (near  responses,  and  the  origin)  there  was  f e e d i n g r a t e s f o r low assume t h a t  the result  discussion. be  feeding rates although  i s valid,  feeding  similar were  collected,  vary  one d e p t h ,  so  functional  of variability i n  i t certainly  that  However, deserves  temperature  i f I  further  acclimation  may  b u t t h e n why s h o u l d maximum  temperature  those  a t one t e m p e r a t u r e  temperatures  deal  measurements  to  fitted  concentrations.  n o t a l s o be  M  the  zooplankton  just  food  the  great  f o r this result,  "V  temperatures  remain  a  I have s u g g e s t e d  responsible  of  of  independent?  were the  carried  water,  And  out a t  from  which  t h e z o o p l a n k t o n do n o t n o r m a l l y  during the course of  a  day.  Lake  w i t h depth, and z o o p l a n k t o n do n o t s t a y a t they  cannot  have  adapted  to  just  one  temperature. Host o f t h e a n i m a l s study that  were  from  t h e temperature  rates and  taken  reflects  to a daily  { o t h e r t h a n D. p u l e x ) t e s t e d the UBCForest  invariance  of  their  an a d a p t a t i o n t o t h i s range  in  Lakes.  I t i s possible  maximum  particular  temperature.  If  "V"  temperature,  b u t " a " does n o t , t h e n t h e f e e d i n g  at  food c o n c e n t r a t i o n s depending  for  different  low f o o d c o n c e n t r a t i o n s t e m p e r a t u r e  feeding  rate.  almost always ash-free  dry  i n this  filtering  environment, depends  rate  on  saturates  on t e m p e r a t u r e , b u t  w i l l h a v e no e f f e c t on  Now s e s t o n l e v e l s i n t h e OBC F o r e s t L a k e s a r e v e r y low ( g e n e r a l l y  between 0.8 and  1.5  ug/ml,  w e i g h t ) . . Some z o o p l a n k t o n a r e known t o u n d e r g o  138  considerable v e r t i c a l most  m i g r a t i o n on  that  daring  of  the  daily  temperatare  vary  suddenly as a r e s u l t  a daily  basis,  which  year they experience c o n s i d e r a b l e  variation.  S u r f a c e water  of heavy  temperatures  r a i n s , f o g , wind,  t o s u c h c o n d i t i o n s by d e v e l o p i n g a wide t e m p e r a t u r e  &n  food  alternative  the  filtering  maximum r a t e . determined  level  might  o n l y by  z o o p l a n k t o n muscle  tolerance  remains  sufficiently  value  of  this  the mechanics enzymes  had  fairly  optima,  muscle  t h e n t h e a n i m a l would  motor a b i l i t y when  enzymes,  over t h i s  f o o d i s abundant,  each  would  If  flat  to  adapted  operate  temperature range. the hunger  level  i n turn  On  would might  o f p r o d u c t i o n o f d i g e s t i v e enzymes. i n v a r i o u s ways t o d i f f e r e n t  response  several  temperature with  equal  t h e o t h e r hand, be  limited  more  be c o n t r o l l e d Possibly  temperature  e v o l v e d d i g e s t i v e enzymes w i t h d i f f e r e n t  be  movement, e t c .  different  be a b l e t o  by t h e r a t e o f d i g e s t i o n , w h i c h the rate  with  that  always a t i t s  maximum, r a t e  of muscle a  high  t e m p e r a t u r e o v e r some r a n g e , o r i f t h e z o o p l a n k t o n had different  adapted  be t h a t u n d e r low f o o d  p r o c e s s i s a l w a y s t u r n e d on, and The  It  concentrations.  hypothesis  c o n d i t i o n s , t h e hunger  can  etc.  seems g u i t e r e a s o n a b l e t h a t t h e z o o p l a n k t o n m i g h t have  o v e r a r a n g e o f low  means  species  regimes  temperature  by  have  optima.  139  5.3.2  ftcclimation Vastly  To  Food  different  f u n c t i o n a l r e s p o n s e s were o b t a i n e d  Diaptomus o r e g o n e n s i s between rates  collection  (see F i g u r e One  simply  is  length  of  measurement of  that  i n the  v e s s e l s was  w a t e r u s e d was  could  the  zooplankton  holding  tanks.  collected  a t one  little  food.  t i m e and  I f t h i s was  The  than  inhibition  of  filtering  r a t e a t low  5 days i t disappeared.  rate  means  sigmoid.  that In  experiment,  the  other  Such an  corresponding words,  during  type  zooplankton  II  filtering  patch  then  i t in  Animals  held  r a t e s a t low  food  is  there  more was  an  food c o n c e n t r a t i o n s , inhibition feeding the  5  in  days  but  filtering  rate  sigmoid  food  feeding curves  in  response  curve of  is  this  at f i r s t s  and  response.  at different  days a l s o produced d i f f e r e n t 18).  place,  the i n c r e a s e  Initially  t h e f u n c t i o n a l r e s p o n s e was  became a s i m p l e  Holding  functional  the change i n magnitude.  after  finally  whole  rates. change i n form o f the  puzzling  so,  were  although  r e g u l a r l y changed, the  have been i n c r e a s i n g hunger t h a t caused  filtering  time  feeding  i t i s p o s s i b l e t h a t i t m i g h t h a v e been t a k e n f r o m a  containing relatively  and  the  for  16|.  depleting t h e i r food  of lake  varying  of t h e a n i m a l s and  the l a k e water i n the  and  by  possible explanation  gradually  supply  Concentration  high  food  concentrations  regimes f o r s e v e r a l (see  Figures  d e n s i t i e s had than  animals  17  lower held  140  in  untreated  satiated  lake  from  indication  water.  5 days o f of  rich  possibly  hungry  to  could  be b e c a u s e t h e y  feeding.  inhibition  concentrations, sufficiently  This  of  There  filtering  because expend  the a  was  also  rates  at  animals  large  were  effort  an low  were  not  for  small  returns. Animals held i n ordinary classic  filtering  functional at  low  r a t e curve  response.  food  zooplankton,  l a k e w a t e r f o r 5 d a y s showed t h e that corresponds  Their f i l t e r i n g  concentrations and  concentrations.  the  than  same  or  The r e d u c t i o n  caused by t h e f a c t  that  they  effort  however, The  than  kept  those  feeding rates  held  slightly  than  concentrations.  the  They  to  and  groups  fed  lower at high  food  could  medium t h a n returns  be  they per  filtering  faster.  w a t e r h a d much at  almost  lower  a l l food  been s t a r v e d t o o much and  affect  to  specific  filtering  mainly f o r low f o o d  rate  2 - 3 hours f o r  food  concentrations  measurements  concentrations  This i n d i c a t e s that the standard  of a l l o w i n g  higher  The l o w c o n c e n t r a t i o n s  lake  had p r o b a b l y  II  poor c o n d i t i o n .  concentration 19).  dilute  type  well  greater  to.  hungry  other  Length o f a c c l i m a t i o n seemed  the  a t high concentrations  were used  in  of  were i n a r i c h e r  them c o n s t a n t l y  zooplankton  were i n v e r y  they  a  r a t e s were much  were u s e d t o and were t h e r e f o r e g e t t i n g unit  to  zooplankton  (see  experimental to  at  that Figure  procedure  acclimate  to  a  14.1  particular  5.4  food  concentration  F u n c t i o n a l Response This  adaptable the  study  Adaptation  t r e a t s f e e d i n g r a t e f u n c t i o n a l r e s p o n s e a s an  t r a i t and t r i e s t o answer t h e  trait  attain  may be i n a p p r o p r i a t e . .  has  optimal  conditions  evolved  in  order  to enable  tactics f o r different  -  specifically  for  question  sets  of  whether  t h e organism t o  of  environmental  d i f f e r e n t s i t u a t i o n s o f food  availability. In s e c t i o n 2.3 a r e values be  that  expected  listed  some  f u n c t i o n a l response  predictions  are  important  conditions,  as adaptable  traits.  food  and p r e d a t i o n c o n d i t i o n s , one would e x p e c t  high  values  "T"  with  limited  of " a " , coupled  low " a " . And e x c e p t  by  predation  or predation  level.  measured  characteristics As  predicted  functional  of  the  to find V",  either  or  rt  initial  feeding  high  populations  slope  of  the  be i n d e p e n d e n t o f l a k e p r o d u c t i v i t y  A c r o s s - l a k e comparison o f t h e f u n c t i o n a l here  indicate  of zooplankton  in  low v a l u e s  i f  Depending on  f o r eutrophic lake  pressure,  f u n c t i o n a l response should  responses  with  the  p a r a m e t e r s "V" and " a " c o u l d  t o assume u n d e r d i f f e r e n t  strategies  about  section  responses  may i n d e e d  2.3, were  that  the  the  food  gathering  be a d a p t a b l e  initial  essentially  slopes the  traits. of  same  the for  142  oligotrophia There  and  was  no  eutrophic  evidence  limited  productive  lakes should  that  lower  the  limited such  lake  predation.  events -  In f a c t  second  values.  functional  be  c h a n g e i n body s i z e  t o reduce p r e d a t i o n  rates "a"  (see F i g u r e s  filtering  rates  "a"  for  Daphnia  Diaptomus k e n a i ,  and  Diaptomus  a  H o l o p e d i u m gibberurn high, to  with  the  and  M  latter  two  H  Daphnia pulex  much more v a r i a b i l i t y . species.  find  to evolve  other  of  life  similar  range  22  -  identical  27).  Maximum  Diaptomus were  values.  Parameters f o r  averaged  result  about was  twice  f o r IK  Pulex i s  eutrophic  D.  e x p e r i m e n t s on (unpublished even D.  in  rosea  the  an  data)  rosea.  In  o l i g o t r o p h i c l a k e i n the h a s .found t h a t D.  absence of  should  does  have a  predation. higher  rosea  UBC  some  as  comparable  species tends t o e x i s t  than  tyrelli. virtually  somewhat s u r p r i s i n g s i n c e t h i s waters  truly  to  essentially  Ceriodaphnia The  were n o t  a very  rosea,  V  and  i n d i c a t e only  or i n t i m i n g  oregonensis  l a r g e range of  highly  pressure.  r e s p o n s e p a r a m e t e r s , and  over  30).  rates,  difficult  a n i m a l s would t e n d  maximum f i l t e r i n g  identical  from  tested here  i t may  -  prediction, that  T h i s may  Most o f t h e s p e c i e s s t u d i e d h e r e had of  28  maximum f e e d i n g  populations  s i n c e the  medians!ms - s u c h a s history  slope  Figures  zooplankton  have h i g h e r  initial  populations  the  filter-feeding  eutrophic by  (see  supporting  predation  probably  waters  in  more  enclosure  Forest,  o u t c o m p e t e D.  Heill pulex  T h i s again* i n d i c a t e s t h a t  maximum  filtering  rate  than  :  1.4.3  P.; pa l e x . .. B u r n s be  significantly  Bigler,  lower  1967) , a l t h o u g h  were  similar.  found  here.  5.5  (1969) f o u n d  pulex f i l t e r i n g  than those of Daphnia she c l a i m e d  (Burns,  rosea 1969)  rates (Burns  that  to and  they  I have no e x p l a n a t i o n f o r t h e c o n t r a r y r e s u l t s  G e n e r a l Remarks Although  a fairly  examined,  i t  functional  response  applicability. difficult with the  that  may  be  However a  o f lake environments  measurements  problem  type  of  : of  time  responses.  conditions,  vertically*  Even  various generally  that  of  circadian required over  and  rythms.  by e c o s y s t e m  a whole  are  temperature  kind  and  over  perhaps  cell  measured  are count under  are migrating  regimes,  patchy  are ; undergoing  of f u n c t i o n a l  m o d e l s i s one  population,  i t  functional  experiment,  incubation  predators, The  makes  feeding strategies  whereas " r e a l " z o o p l a n k t o n  food  feeding  method e x c e p t  they  was  geographical  scale  flow  long  encountering d i f f e r e n t  distributions  filter  Zooplankton  practical  continuous  are instantaneous i n  constant  of  quite general i n their  a s measured by any  instantaneous  averaged  appears  range  data gathered i n t h i s study.  elaborate  results  limited  to completely assess zooplankton  responses, an  Daphnia  response  w h i c h i s somehow  depths,  temperature  144  profiles  and  encountered  patches  daily.  impossible,  To  of  measure  using  This i s a  i t should  different models*  the  the  be  approximation, tested  response  in  hypotheses.  on f u n c t i o n a l  functional  zooplankton  response  collection  on f u n c t i o n a l r e s p o n s e  indication  of  of prior  i n the  study  the  high  f o r some s p e c i e s ,  correlated  with  time  food  conditions,  and  the different  Some o f t h e s e r e s u l t s do n o t g i v e a  clear  t h e u n d e r l y i n g m e c h a n i s m s , b u t t h e y do s u g g e s t  experimental  avenues  the  which  I t would be i n t e r e s t i n g ,  comprehensive  functional responses  feeding  might  zooplankton.  behavior  geographical f o r perhaps  r a t e s i n warm w a t e r s with  this  response,  o f f e e d i n g parameter v a l u e s over  on  other  Belief  to  a n d f e e d i n g measurement, t h e  information  feeding  on  models  for sensitivity  o b t a i n e d a t low t e m p e r a t u r e s  s p e c i e s and l a k e s .  more  be  based  but  r e s u l t s have emerged f r o m  o f temperature  similarity  several  would  whenever f u n c t i o n a l r e s p o n s e s a r e  carefully  interesting  rates  changes  effect  response  they c o n t a i n .  effect  between  a  concentrations  p r e d i c t i o n s s h o u l d be tempered b y c o n s i d e r a t i o n o f t h e  Several  feeding  such  justifiable  functional-  hypotheses  -the  food  so instantaneous r a t e s or approximations  i n s t a n t a n e o u s r a t e s a r e used required.  different  of  valuable  filter-feeding  f o r example,  and  seasonal  to survey  two s p e c i e s , one w i t h  (e.g.  highest rates i n cold  yield  Daphnia r o s e a waters  (e.g.  ).  do  a  of  highest  and  the  Holopedium ) .  145  A temperature takes  study c o u l d  f o r maximum  be done t o  filtering  out  to  adapt  rates  t e m p e r a t u r e a n d whether i t i s rates  find  possible  for  how  long  i t  t o changes i n  maximum  feeding  to adapt t o temperature. This  study  change i n t h e response,  indicated  shape  namely,  of the  that  the  three  to  length  which  the  experiment* and p o s s i b l y a l s o concentration.  In l i g h t  the  of  influence  f o r m w o u l d be v e r y  of  ecosystem  time  rate,  between the  functional zooplankton  level  a n i m a l s were e x p o s e d  of  o f these r e s u l t s , a study focussed  these three relevant  studies.  food  before the  t h e r a t e o f change o f t h a t  food on  f a c t o r s on f u n c t i o n a l r e s p o n s e  t o comparative s t u d i e s  r a t e s and t o a p p l i c a t i o n o f t h e s e agnatic  may c a u s e a  laboratory-measured  c a p t u r e a n d measurement o f f e e d i n g concentration  factors  rates to f i e l d  of  feeding  situations or  1.46  6  Anraku,  M.  1963.  BIBLIOGRAPHY  Feeding  (Review)  ( i n Japanese).  in  9:10-35.  Japan  Bogdan,  K.G.  and  Diaptomus Limnol.  Boyd,  D.C.  and  of  Inform.  HcNaught. Daphnia.  planktonic  Bull,  1975.  on  copepods  Planktonology  Selective feeding  Verh.  Internat.  by  Verein.  19:2935-2942-  CH.  1976..  feeding  habits  Selection  of  particle  copepods: a plea f o r reason.  s i z e s by  Limnol.  filter-  Oceanogr.  21(1) : 175.  Buikema,  A-L.,  Daphnia  Jr.  pulex as a  acclimation.  Burns,  C.8.  filter  C.W.  feeding  function  The  1969. and  of  rate of body  41(4):  and  the  Oceanogr.  Relation body s i z e  the  size,  cladoceran light  and  515-527.  relationship  Cladocera  Limnol.  temperature,  Filtering  Hydrobiologia  1968.  ingestion.  Burns,  1973.  between body s i z e  maximum s i z e  of  of  particle  13:675-678.  between  filtering  in four species  rate,  of Daphnia  .  147  Limnal-  Oceanogr.  B u r n s , C M . and F . H. rates  of  of yeast.  Cahn, B.D.  14:693-700.  Bigler.  1967.  Daphnia r o s e a Limnol.  1967.  Comparison  of  filtering  i n l a k e water a n d i n s u s p e n s i o n s  Oceanogr.  Detergents  12 (3) : 492-502.  i n membrane  filters.  Science,  155:195-196.  Chen,  C v f - a n d 6.T. Aquatic  Environments.  Interior.  Crowley,  P.H.  pulex  Orlob.  Beport  Ecological  Simulation f o r  t o O.9.B.B., U.S.  Dept. o f  156 pp.  1973.  in  1972-  Filtering  Bintergreen  rate  lake  inhibition  water.  of  Limnol.  Daphnia  Oceanogr.  18(3):394-402.  Crowley,  P.H.  1975.  constant.  Cushing,  D-H.  primary Beunion, 149-154.  J.  Natural  Theor.  1958.  selection  Biol.  a  Conseil  Perm.  the  Michaelis  50(2):461-476.  The e f f e c t  production:  and  review.  o f grazing i n reducing the Bappt.  Proces-Verbaux  I n t e r n . . E x p l o r a t i o n H e r , 144:  148  Cushing,  D.H.  1976.  Oceanogr.  DiToro,  0.,  D. J .  0*Connor  model o f  waters.  Env.  Dugdale,  B.C.,  and  B. V.  phytoplankton Eng. and  1967.  Sci.  B.W.,  Nutrient  identification  Oceanogr.  Erken.  Limnol.  Thomann.  populations Prog.,  1970. in  and W.H.  Thomas.  constants  marine p h y t o p l a n k t o n .  natural  Manhattan C o l l e g e ,  B.W.,  limitation and  in  the  significance.  sea: Limnol.  J.N.  Sogers,  for  1969.  Comparison  of  growth  and n i t r a t e  uptake o f  J . . Phycol.  and J . J .  half-  5:375-379.  M c C a r t h y . .,  1969.  Half  s a t u r a t i o n c o n s t a n t s f o r uptake o f n i t r a t e  and ammonia  marine p h y t o p l a n k t o n .  14:912-920.  Frost,  k  12(4) :685.  saturation  Eppley,  Lake  H.X.  dynamics,  Eppley,  in  21 ( 3 ) : 3 4 9 .  dynamic  Bronx,  Grazing  B.W.  1972.  particles planktonic Oceanogr.  on  Limnol.  Oceanogr.  by  E f f e c t s o f s i z e and c o n c e n t r a t i o n o f f o o d the  copepod  feed ing  behavior  Calanus  17(6):805-815.  of  pacificus  the .  marine Limnol.  149  Frost,  B-H. . 1975.  pacificus  Fujii,  K.,  A t h r e s h o l d f e e d i n g behaviour Limnol.  C.S.  simple  Oceanogr.  Holling,  generalized  and  model  20(2)3  P.H.  of  Calanus  263-  Hace.  attack  in  ( i n prep.) .  by  predators  A and  parasites.  Gauld,  D.T.  J.  1951.  Har. , B i o l .  Gliwicz*  Z.H.  The  g r a z i n g r a t e o f p l a n k t o n i c copepods.  Ass.  1975.  U.K.  Effect  photosynthetic a c t i v i t y Verb.  Gliwicz,  Int.  Verein.  Z.H.  1977.  Goodman,  E.D.,  1973.  pol.  and  zooplankton  composition of  Limnol.  size  selection  feeding zooplankton  Zeren,  theoretical  D.J.  and  experimental  control  ecosystem.  Bes.  p r o p o s a l t o Ecosystem  Research,  phytoplankton.  and  i n an  H a l l , and  and  wash.  on  19:1490-1497.  prediction  8.S.F.,  grazing  seasonal eutrophic  25 (2) : 179- 225.  B.H.  A  of  Food  s u c c e s s i o n of f i l t e r l a k e . ,• E k o l .  29:695-706.  of  Administered  Michigan  State  Univ.  P.H.  approach  eutrophication  through  Crowley.  of  Analysis  a  to lake  Program,  Div. of Engineering  150  G r e e n , J.D.  1975.  F e e d i n g and r e s p i r a t i o n  copepod C a l a m o e c i a  Haney, J . F .  1971.  zooplankton  i n t h e New  1 o c a s i Brady. , Oecologia  An i n s i t u  method f o r t h e  grazing  rates.  Zealand  21:345-358.  measurement  Limnol.,  of  Oceanogr.  1 6 ( 6 ) : 970.  Haney, J . F .  1973.  An i n  situ  activities  of  natural  Hydrobiol.  7 2 ( 1 ) : 87-132.  Haney, J . F . and D . J . and  filter-feeding  Hydrobiol.  Hargrave,  Fish.  Bes-  Geen.  Can.  Diel  the  grazing  communities.  vertical  o f Daphnia  1970.  phytoplankton 27(8):  Lawton, J.8.  responses  parasitoids.  C.S.  Bd.  J.H.  functional  Holling,  1975..  activities  on two n a t u r a l  M.P.,  zooplankton  of  .  Arch.  migration Archiv f u r  75(4):413-441.  B.T., and G.H.  grazing  Hassell,  Hall.  examination  J.  1959.  Anim.  by  Effects  populations.  copepod Journ.  1395.  Beddington. invertebrate  Ecol.  of  1977-  Sigmoid  predators  and  46 (1):249-262-  Some c h a r a c t e r i s t i c s o f s i m p l e t y p e s  p r e d a t i o n and p a r a s i t i s m . C a n . , Entom.,, 91:385-398.  of  151  Holling,  CS.  prey  1965.  d e n s i t y and  regulation.  Ivlev,  The  7.S-  its  Hem.,  1961.  fishes.  f u n c t i o n a l response of predators role  Ent.  in  Soc.  mimicry Can.  Experimental  (trans.  D. ,  45:  ecology  Scott)  and  Yale  to  population  1-60.,  o f the  Univ.  feeding  Press.  of New  Haven.  Kibby,  H.V.  1971.  behavior  of  Effect  of  Daphnia  temperature  rosea.  on  the  Limnol.  feeding  Oceanogr.  16(3) :580-581.  Krepp,  S.B.  1977.  populations of of B r i t i s h  Kryutchkova,  Genotypic Daphnia pulex.  N.H.  Scourfield.  B.K.  and  and  7.  19. S c .  Sladecek.  variation  Thesis,  Hydrobiologia  B. H.  Frost.  Oceanogr.  1969.  growth o f Daphnia 33:  1976.  response to changes i n s i z e Limnol.  phenotypic  in  University  Columbia.  r e l a t i o n s o f f e e d i n g and  Lam,  and  and  21 (4) :490.  Quantitative pulex  obtusa  47-64.  Model o f c o p e pod concentration  filtering of  food.  152  L a m p e r t , W.  1974.  A method f o r d e t e r m i n i n g  zooplankton.  Leendertse,  J . J . and  simulation seas: Mew  1976.  Oceanogr.  Hc&llister,  CD.,  The f i l t e r - f e e d e r shapes  1971.  grazing  production  Bioqeoqraphy  Some  studies.  of  coastal  R-709-NYC, The  as an o p t i m a l feeding  aspects  FfiBC T e c h .  And E.O., W i l s o n . , Princeton  J . J . and  B.C.  forager,  curves.  1965.  feeding behaviour  of  Limnol.  nocturnal  Report no.  1967.  Theory  University Press,  Dugdale. uptake  marine phytoplankton.  J.H.  and  and  by p l a n k t o n i c h e r b i v o r e s i n r e l a t i o n  n i t r a t e a n d ammonia  HcHahon,  estuaries  21 ( 4 ) : 5 0 1 .  M a c & r t h u r , R.H.  McIsaac,  mixed  water-quality  Institute.  predicted  continuous to  1971.,, k  J a m a i c a Bay S i m u l a t i o n .  Hand  s e l e c t i o n by  19:995- 998.  Gritton.  model f o r w e l l  York C i t y  the  Oceanogr-.  E.C-  Vol. i i i ,  Lehman, J . J . and  Limnol.  food  1969.  by  natural  248.  of  Island  Princeton.  The  kinetics of  populations  of  Deep-Sea R e s . , 16: 45-57.  Some p h y s i c a l f a c t o r s i n f l u e n c i n g t h e o f Daphnia  magna  Strauss.  Can-  J.  153  Zool.  McMahon,  43: 603-612.  J.H. and P.H. , B i g l e r . , 19.63*  Mechanisms r e g u l a t i n g  t h e f e e d i n g r a t e o f D a p h n i a magna S t r a u s s . Zool.  HcMahon,  J.H.,  and  F. H.  fiigler-  phosphorus.  D.T.  1970.  Marshall,  Fish.,  S.H.,  Calanns  supply  neritic Biol.,  labelled  oceanogr.  rates  Bd.  Can.  A.P.  Orr. Food  rate of with  10: 105-113-  and f o o d s e l e c t i o n i n Lake,  B.C.  2 7 : 13-20.  1955., uptake,  On t h e b i o l o g y o f assimilation J.  and  Mar., B i o l .  34:495-529-  Mayzaud, P. a n d B . J . food  foods  i n a d u l t and s t a g e 5 C a l a n n s .  O.K.  Feeding  (Copepoda) from M a r i o n  f i n m a r c h i c n s ?.  excretion Ass.  Bes.  and  Limnol.  Grazing  Diaptomus o r e g o n e n s i s Journ.  1965-  magna S t r a u s s i n d i f f e r e n t  radioactive  and  Journ.  4 1 : 321-332.  Daphnia  McQueen,  Can.  Conover.  on  the  zooplankton. Ostend,  activity I n : Proc.  belgium,  E.J. Jaspers  1976.  Sept.  Influence of of  potential  d i g e s t i v e enzymes o f  10th E u r . 17-23, 1975.  Symp.  Mar.  Persoone,  (Eds)-, Oniversa, H e t t e r e . ,  G.  154  Mayzaud,  P. and  time  S.A.  factor  in  herbivorous matter.  Morris,  Poulet. the  trophic  I . and  Oceanogr.  C.S.  relationships  Limnol.  M.M.  1963.  Mullin,  between  occurring particulate  1972.,  A  new  by f i l t r a t i o n  Oceanogr.  with  method  for  continuous  17(3):490-493.  Some f a c t o r s a f f e c t i n g  m a r i n e c o p e p o d s of t h e g e n u s C a l a n u s . 8:  of the  23 (6) : 1144-1154.  Xentsch.  concentrating phytoplankton  Mullin.  The i m p o r t a n c e  c o p e p o d s and n a t u r a l l y  Limnol.  stirring.  1978.  the feeding of  Limnol.  Oceanogr.  F.J.  Fuglister.  239-250.  M.H.,  1975.  E.  Fuglister  Ingestion  concentration  Stewart  and  by p l a n k t o n i c g r a z e r s a s a f u n c t i o n o f  of food.  Limnol.  Oceanogr.  20(2):259-  262.  O'Connors,  H.B.,  Particle-size estuarine  L. F.  Small,  and  m o d i f i c a t i o n by  copepod  Acartia  two  P.L.,,,  Donaghy.  size  classes  cjansi.  Limnol.  1976. of  the  Oceanogr.  2 1 ( 2 ) : 300.  Parsons, of  T.R.,and M.  Takahashi.  phytoplankton  cell  1973. size.  Environmental Limnol.  control  oceanogr.  155  18(4):511-515.  Parsons,  T.B.,  Some  B.J.  observations  grazing  on  Pennak, B.H.  The  K.G.  algae  ingested  Potts,  and  Regulation  L.  and  Ocean-  of  1967*  zooplankton  concentration  Soc.  Jap.  Invertebrates  23:  of  of  10-17.  the  Pnited  Co.  passage of g e l a t i n o u s  Daphnia.  Verh.  Internat.  green  Verein.  P a r r y . .,  ftnimaIs.  Osmotic  York, HacMillan  Seasonal  particles.  The  Hen  1964.  grazing  Marine B i o l .  of  and  Ionic  Co.  Psendocalanus  25(2):109-123.  k i n e t i c s of f u n c t i o n a l  response.  Am.  111 (978): 289-300.  F.H.  food  Fulton.  V i a b l e gut  G.  1974.;,  1977.  Hat.  Bigler,  in  S.ft.  m i n u t u s on  Seal,  by  J . D.  19:2840-2850.  H.T. W.,  Poulet.,  size  J*  Ronald Press  and  dependence  Fresh-Hater  1975.  Limnol.  the  cell  blooms.  1953*  States.  on  the  phytoplankton  Porter,  LeBrasseur,  and  1961.  The  relation  feeding r a t e of  between  concentration  D a p h n i a magna S t r a u s .  Can.  of J.  15.6  Zool-  Bigler, A  39:857-868.  P.H.  1971.  Manual  of  Productivity G.G.  Byther, the  Methods  i n Fresh  Hinberg.  J.H.  for  the  Haters,  Corwin.  E d . by W.T.  Edmondson  I n h i b i t o r y e f f e c t s of phytoplankton  and s u r v i v a l .  D.H. 1971.  matter i n  6,  in  Assessment o f Secondary  f e e d i n g o f D a p h n i a magna n i t h  J.H.,  r a t e s , Chapt.  and  B l a c k w e l l , London.,  1951.  reproduction,  Byther,  Zooplankton feeding  the  Henzel,  reference  Ecology  E.H.  to  growth,  35: 522-533.  Huburt, C . J .  Lorenzen,  The p r o d u c t i o n  and u t i l i z a t i o n  Peru  current..  coastal  upon  N.  of organic  Invest.  Pesg.  35(1) :43-59.  Schindler, rates  D. W. of  1968.; F e e d i n g , Daphnia  conditions J.  Solomon,  Anim-  and  their  Ecol.  H.E.  populations.  magna  1949.  a s s i m i l a t i o n and r e s p i r a t i o n  under  relation  various  environmental  to production  estimates.  37:369-385.  The  natural  control  J o u r n a l o f Animal Ecology  S t a r k w e a t h e r , P.L. / 1975.  Diel  patterns  of  animal  18(1):1-:35.  of grazing  i n Daphnia  157  pulex  Leydig.  Vera.  Interna*:.  Verein.  Limnol.  19:2851-2857.  Steele,  J.  1974.  Harvard.  Stewart,  The  Dniv.  P.H.,  Structure  of  Marine  Ecosystems.  Press.  and  fi.fi.  the  Levin.  1973.>  Partitioning  resources  and  model and  some g e n e r a l c o n s i d e r a t i o n s ,  am.  1975.  model o f t h e  of  outcome o f i n t e r s p e c i f i c c o m p e t i t i o n : Bat.  a  107:  171-198.  Walsh,  J.J.  upwelling  Halsh,  J.J.,  &  ecosystem.  and  simulation  Dept.  Halters,  Of  48,  C.J.  1975.  CJ.  IBP  And  COHSYS  a  seagoing  University 1.  O p w e l l i n g Biome T e c h n i c a l Of  Peru  201--236.  Oceans,  version of  of  Special Series.  Hash.  Dynamic  Proceedings  Ecosystems, J u l y  1971.  22:  a user's guide to the  spatial  o c e a n . , 0.  strategies.,  Halters,  Bass.  program -  no.  simulation  Deep-sea Bes.  P.B.  W a s h i n g t o n ' s IBM Beport  spatial  models of  the  1974.  Pp.(68-82).  H.C.  Clark-  and SIHS  1973.  evolutionary Conference  on  Determinants  of  158  feeding  strategy  in  plankton communities.  Unpublished  manuscript.  fleers,  S.T. a n d T.  Zaret.  1975.,  r e l a t i o n s h i p s i n Gatun Lake, Verein.  Hhite,  ed.  D.S.  Ecology  HcGraw H i l l .  1973.,  Panama.  -  Zooplankton  Verb.  Internat.  19:1480-1483-  H a n d l e r , and S m i t h .  4th  Bilson,  Limnol.  Phytoplankton  1968.,  Principies  o f B i o c h e m i s t r y,  1149 pp-  Food  54(4) : 909 -914.  size  selection  among c o p e p o d s .  JOURNAL PUBLICATIONS  Holling, CS. and S. B u c k i n g h a m . 1976. model o f p r e d a t o r - p r e y f u n c t i o n a l B e h a v i o r a l Science, 21(3):183.  A behavioral responses.  Buckingham, S a n d r a , C a r l J . W a l t e r s , and P i e r r e K l e i b e r . 1975. A procedure f o r estimating gross production, n e t p r o d u c t i o n , and a l g a l c a r b o n c o n t e n t u s i n g l ^ C . V e r h . I n t e r n a t . V e r e i n . L i m n o l . 19:32-38. Himamowa, BuBu (pseud.) 1975. The O b e r g u r g l M o d e l : a microcosm o f economic growth i n r e l a t i o n t o l i m i t e d ecological resources. N a t u r e and R e s o u r c e s 2:10-21. (Himamowa i s a pseudonym f o r m y s e l f and 6 o t h e r a u t h o r s . V e r t i n s k y , I . , S.L. Buckingham, C J . W a l t e r s , and G. Z a l t m a n . 1972. F a m i l y p l a n n i n g computer s i m u l a t i o n : t h e C o s t a R i c a p o p u l a t i o n m o d e l . S i m u l a t i o n and Games, 3 ( 2 ) : 123-145.  THESES AND  NON-REFEREED PUBLICATIONS  W a l t e r s , C a r l J . and S a n d r a B u c k i n g h a m . 1975. A C o n t r o l s y s t e m f o r i n t r a s e a s o n salmon management. In " I n t e r n a t i o n a l I n s t i t u t e f o r A p p l i e d Systems Analysis; C o n f e r e n c e P r o c e e d i n g s , Workshop on Salmon Management". CP-75-2. Buckingham, S.L. 1973. A p l a n k t o n p r o d u c t i o n model f o r the western G u l f of S t . Lawrence. I n : Volume o f W o r k i n g P a p e r s f o r NATO C o n f e r e n c e on M o d e l l i n g o f M a r i n e S y s t e m s , J u n e , 1973, i n O f i r , P o r t u g a l . Buckingham, S.L. 1970. C o n t r i b u t i o n d l ' e t u d e du b r u i t de f o n d a s s o c i e aux d i o d e s S c h o t t k y . Thesis (Doctorat de 3 Cycle), F a c u l t e des S c i e n c e s , U n i v e r s i t e de M o n t p e l l i e r , F r a n c e . e  

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