The wonderful world The wonderful world of zooplanktonof zooplankton

(and what it means to us)(and what it means to us)

What did we sample?What did we sample?

www.glerl.noaa.govwww.kulak.ac.be

www.ibss.iuf.net

Daphnia

nauplii

Calanoid copepods

Also:•Cyclopoid copepods•Bosmina•Rotifers•Other zooplanton

Why should we study these Why should we study these tiny organisms?tiny organisms?

Food Web DynamicsFood Web Dynamics

Productivity IndicatorProductivity Indicator

Chemistry IndicatorChemistry Indicator

Where did we go?Where did we go?(a little memory jog)(a little memory jog)

Onieda LakeOnieda Lake Deer LakeDeer Lake Arbutus LakeArbutus Lake Green LakeGreen Lake Rich LakeRich Lake Onondaga LakeOnondaga Lake

syracuseh20.tripod.com

www.dec.state.ny.us www.dreamscape.com

www.davehonan.com

How did we collect the How did we collect the data?data?

aslo.org planktonweb.ifas.ufl.edu

Schindler Trap Net Tows

The details are in the The details are in the methods…methods…

Schindler TrapSchindler Trap Allowed us to sample at specific depths, Allowed us to sample at specific depths,

usually at epi, meta, and hypolimnionusually at epi, meta, and hypolimnion Emptying whole trap on lap was a hazardEmptying whole trap on lap was a hazard

Net TowsNet Tows Allowed sampling for zooplankton Allowed sampling for zooplankton

throughout entire water columnthroughout entire water column Got as close to lake bottom without Got as close to lake bottom without

actually touching it and disturbing actually touching it and disturbing sedimentssediments

Data ManipulationsData Manipulations

Pooled dataPooled data Combined all types of “zoops” for each Combined all types of “zoops” for each

lake to compare abundance within each lake to compare abundance within each zone and each lakezone and each lake

Cross Lake ComparisonCross Lake Comparison Population structure of zooplankton taxa Population structure of zooplankton taxa

within each lake separatelywithin each lake separately

Zooplankton Depth Trends

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epi meta hypo chemo monomo

Depth

Nu

mb

er o

f In

div

idu

als/

L

Oneida Lake

Deer Lake

Arbutus Lake

Green Lake

Rich Lake

Onondaga Lake*

* No Data Available

Zooplankton Depth TrendsZooplankton Depth TrendsDielDiel MigrationMigration – movement out of epilimnion during day to escape – movement out of epilimnion during day to escape

predation by vertebrate predators (fish), move up to epilimnion predation by vertebrate predators (fish), move up to epilimnion at night to feedat night to feed

- Zoops in Arbutus, Deer, and Rich Lakes followed the patternZoops in Arbutus, Deer, and Rich Lakes followed the pattern

- Green Lake showed pattern; high zoop abundance at Green Lake showed pattern; high zoop abundance at chemocline due to purple sulfur bacteria food sourcechemocline due to purple sulfur bacteria food source

- Oneida Lake zoops did not follow the pattern- Oneida Lake zoops did not follow the patternWhy???Why???

1 )1 ) Possible that sampling could have been affected by very Possible that sampling could have been affected by very windy conditions; lake is completely mixed (shallow)windy conditions; lake is completely mixed (shallow)

2)2)Missing data for metalimnion zooplankton density….. Missing data for metalimnion zooplankton density….. …………maybe we would have seen the pattern if we had this datamaybe we would have seen the pattern if we had this data

Zooplankton per Liter in Water Column

0.00

10.00

20.00

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90.00

OneidaLake

Deer Lake ArbutusLake

Green Lake Rich Lake OnondagaLake*

Lake

Ind

ivid

ual

s p

er L

iter

Why so many zoops in Deer Why so many zoops in Deer Lake?Lake? We conclude:We conclude:

INCONCLUSIVE RESULTSINCONCLUSIVE RESULTS

No phosphorous data available for this LakeNo phosphorous data available for this Lake

Nothing extraordinary shown in other YSI Nothing extraordinary shown in other YSI parametersparameters

Possible allochthonous food source (forested Possible allochthonous food source (forested watershed)watershed)

Perhaps few predators of zoops in Deer Lake Perhaps few predators of zoops in Deer Lake (would need to sample the fish population)(would need to sample the fish population)*

*Anyone in the fisheries class??

Cross Lake Zoop Cross Lake Zoop ComparisonComparison

Onondaga Oneida Deer

Arbutus Green Rich

What does the cross-lake comparison tell us?

Calanoids comprise >40% of the zoop pop. in Calanoids comprise >40% of the zoop pop. in every lake every lake exceptexcept Onondaga ( Onondaga (DaphniaDaphnia dominate)dominate)

Also highest diversity of zoop taxa in Onondaga Also highest diversity of zoop taxa in Onondaga Lake (six different taxa)Lake (six different taxa)

Why? Chlorophyll – extremely high abundance of Chlorophyll – extremely high abundance of

chlorophyll in Onondaga Lake, much of which is chlorophyll in Onondaga Lake, much of which is chlorophyta (green algae)….chlorophyta (green algae)….remember remember Daphnia Daphnia feeding ecology….feeding ecology….

We see small percentages of We see small percentages of DaphniaDaphnia when when chlorophyta levels are low (Oneida & Arbutus)chlorophyta levels are low (Oneida & Arbutus)

Tying it all together…Tying it all together… Oneida Lake – Population of zoops is fairly low Population of zoops is fairly low

- eutrophic, but fairly low chlorophyll (zebra - eutrophic, but fairly low chlorophyll (zebra mussels?)mussels?)

- has abundant fisheries; top-down food web - has abundant fisheries; top-down food web effectseffects

Green Lake – Fewest number of zoops in Fewest number of zoops in epilimnionepilimnion

- very oligotrophic; clear- very oligotrophic; clear

- limited by chlorophyll amounts, except in - limited by chlorophyll amounts, except in chemoclinechemocline

- water clarity of lake leads to abundance of - water clarity of lake leads to abundance of specialized red calanoid copepods specialized red calanoid copepods

Onondaga Lake – Only lake with high Only lake with high percentage of percentage of DaphniaDaphnia, also highest , also highest diversitydiversity

- highly eutrophied, lots of chlorophyll - highly eutrophied, lots of chlorophyll (chlorophyta)(chlorophyta)

- high conductivity, would expect to see - high conductivity, would expect to see lowerlower diversity of zoops diversity of zoops

- no data on depth trends- no data on depth trends

Deer Lake – Most zoop in net tows - data shows moderate pH, chlorophyll, and

Oxygen levels, no data for phosphorous - lack of predators?

Arbutus Lake – High abundance of rotifers (344)

- skewed hypolimnion abundance, but not reflected in net tow percentages…hmmmm

- perhaps data were recorded wrong (other values were 2.08 each for calanoids, cyclopoids and nauplii)

Rich Lake –

Did not exhibit any extreme measurementsDid not exhibit any extreme measurements

- fairly low chlorophyll levels- fairly low chlorophyll levels

- would not expect to see a large - would not expect to see a large population of zoops (fits expectations)population of zoops (fits expectations)

Further MeasurementsFurther Measurements

Resample all lakes for greater Resample all lakes for greater replicationreplication

Sample at night to observe vertical Sample at night to observe vertical diel migration patterns through the diel migration patterns through the water columnwater column

Sources of ErrorSources of Error

Schindler trap vs. net tow values for Schindler trap vs. net tow values for Arbutus Lake – very high zoop Arbutus Lake – very high zoop abundance in trap; much lower in netabundance in trap; much lower in net

Missing DataMissing Data Wind on day we sampled Oneida LakeWind on day we sampled Oneida Lake

- net was “nearly horizontal in water - net was “nearly horizontal in water column,” so Schindler trap could have column,” so Schindler trap could have been compromised alsobeen compromised also

QuestionsQuestionsoror

Input?Input?