Zooplankton by yurtgc548

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									Zooplankton

    Mike Holdsworth
    Jackie Anderson
Importance of Zooplankton

• Food Web
  – Trophic link
• Indicator
  – Ecosystem
  – Contaminants
• Biological processes
  – Nutrient cycling
• Biocontrol
  – Algal blooms
Parameters studied

             • Species abundance
             • Community dominance
             • Whole lake interactions
             • Differences between lakes
Lakes Studied

• Oneida Lake
• Arbutus Lake
• Deer Lake
• Rich Lake
• Onondaga Lake
• Green Lake
Sampling Methods

• Shindler trap
  – Distinctive depths
  – Lake zones
• Net tow
  – Whole water column (excluding Green Lake)
• Samples anesthetized with Seltzer
• Preserved in ethanol
Lab Methods

• Concentrated sample
• Diluted to known volume
• Examined known subvolume
• Identification of individuals from
  subvolumes
  – 100 specimens of same species
• Data
Data Manipulation; Net Tows

• Took net tow averages from each lake
• Calculated relative percentages of taxa
  present in samples
• Graphical representations
Data Manipulation; Schindler Traps

• Relative percentages of taxa by lake zones
  for each lake
• Table of most concentrated Schindler
  depth and deepest point sampled depth
 Whole Water Column; Net tows
• Calenoid copepods
 dominant in all lakes
 but Onondaga
  – 85% Arbutus Lake
  – 47% Oneida                               Onondaga Lake net tow averages


• Daphnia dominated in
                                                        nauplii
                                             rotifers    4%
                                               4%
                                                                     calanoid

 Onondaga                Bosmina
                           2%
                                                                       27%



  – Fewer total
    zooplankton
                                                                                cyclopoid
                                                                                  11%
                                   Daphnia
                                    52%
                    Oneida Lake Net tow averages                                          Deer Lake Net tow averages
       rotifers                         nauplii
         5%                              6%
 Daphnia
   5%

                                                                                              nauplii
                                                                                               23%
                                                   calanoid
                                                     47%
                                                                                   rotifers
                                                                                     1%
                   cyclopoid
                     37%                                                         Daphnia
                                                                                   5%
            Arbutus Lake net tow averages
                                  Bosmina                                           cyclopoid                        calanoid
                                    0%
                                                   rotifers                            6%                              65%
                  Daphnia
                                                     1%
                    4%

cyclopoid
  10%




                                                                                              Rich Lake net tow averages

                                                                                         Daphnia         rotifers
                                                              calanoid                    13%              3%
                                                                85%




                               Green Lake net tow averages

                                    rotifers      nauplii                    cyclopoid
                                      3%           8%
                      Daphnia
                                                                               19%
                        5%

                    cyclopoid
                                                                                                                                calanoid
                      16%                                                                                                         65%

                                                                  calanoid
                                                                    68%
Specific Depths; Schindler Trap
                                                              Epilimnion Oneida Lake
                                                 rotifers
                                      other zoop   0%


• Oneida lake
                            Bosmina      2%
                                                 nauplii
                              0%
                                                   0%
                                                            calanoid                 calanoid

  – Cyclopoid dominate
                         Daphnia                              31%                    cyclopoid
                           2%                                                        Daphnia

    epilimnion                                                                       Bosmina
                                                                                     other zoop


  – Calonoid dominate
                                                                                     rotifers
                               cyclopoid
                                 65%                                                 nauplii

    hypolimnion                                              hypolimnion Oneida Lake
                                                                         rotifers
                                                            other zoop
                                                                           0%
                                                               1%
                                                                         nauplii
                                                            Bosmina                               calanoid
                                                                          0%
                                                             12%                                  cyclopoid
                                                                                   calanoid
                                                      Daphnia                                     Daphnia
                                                                                    38%
                                                       16%                                        Bosmina
                                                                                                  other zoop
                                                                                                  rotifers
                                                             cyclopoid
                                                               33%                                nauplii
                                                                          epilimnion Arbutus Lake
                                                                     rotifers
                                                     Bosmina           2%
                                                       0%                  nauplii
                                                                            8%               calanoid
                                                    Daphnia
                                                                                             cyclopoid
                                                     10%
                                                                                             Daphnia
                                                  cyclopoid
                                                                                             Bosmina

• Arbutus Lake
                                                     9%
                                                                                             other zoop
                                                                              calanoid
                                                                                             rotifers
                                                                                71%
     – Rotifers at depth                                                                     nauplii



     – Possible explanations
          metalimnion Arbutus Lake                     hypolimnion Abbutus Lake
                         cyclopoid
          calanoid                                              calanoid
                            1%
            1%                                                    1%
                                                     nauplii                    cyclopoid
                                     calanoid                                               calanoid
nauplii                                               1%                           1%
 1%                                  cyclopoid                                              cyclopoid
                                     Daphnia                                                Daphnia
                                     Bosmina                                                Bosmina
                                     other zoop                                             other zoop
                                     rotifers                                               rotifers
              rotifers                                         rotifers
                                     nauplii                                                nauplii
               97%                                              97%
                                                    monomolimnion

• Green lakes
  – 100% calanoid
    dominance in                                                    calanoid

    monimolimnion
  – Why?
                                                    calanoid
                                                     100%


  – Dominant in all layers
    but epilimnion


               epilimnion Green Lake



                      calanoid         calanoid
       rotifers
                        15%
        25%                            cyclopoid
                                       Daphnia
                                       Bosmina
     Daphnia                           other zoop
      15%               cyclopoid      rotifers
                          45%          nauplii
• Daphnia dominated Rich Lake
  – Epilimnion
  – Hypolimnion
• Differs from net tow data
Schindler Summary
           Depth of most   Deepest depth
Lake        zoops (m)        sampled (m)
Oneida            1              8
Deer              3              3
Arbutus           7              7
Green          11 to 15          35
Rich             11              11


Onondaga                         14
Conclusions
• Net tow data and Schindler trap data did not
  always correspond
  – Patchiness
  – Net tow may not reach bottom
  – Net tow mixes layers
• Copepods were important to all communities
• Communities could be very different between
  lake layers
Sources of Errer

• Identification difficulties
• Subsample stirring
• Recounting
• Lake patchiness

								
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