1. Assessing the Ecological Risk of the Effects of Climate Change on Zooplankton in Lake Champlain
Alex Gibson
Mark Rasmussen
Ben Sherman
Josh Stewart
Brittany A. Weldon
ENSC 202
Spring, 2009
Daphnia. Spike Walker. 2005© Microscopy UK or their contributors.

2. Problem:
Increasing water temperatures in Lake Champlain due to climate change will alter zooplankton populations and cause subsequent food web disruption at higher trophic levels.

3. Overview Climate Change Zooplankton in Lake Champlain
Trophic cascades and food web
Population dynamics
Food sources and phytoplankton
Predation
Invasive species
Conclusions & recommendations

4. Climate Change
The Greenhouse Effect: Visible light passes through the earths atmosphere and is either absorbed or reflected into the atmoshphere.

5. Examples: 1. Comparison of Lakes at Varying Altitudes
Characteristics/morphometry determine zooplankton biomass potential.
Higher latitudes nutrient deficient.
Lower latitudes nutrient rich.
2. Photoperiod influences biomass.

6. Compensating for increased amounts of greenhouse gases, the mass balance of the earth is disrupted.
Compensate managing of inputs and outputs by increasing temperature.
Since a thicker blanket of greenhouse gasses have reduced energy loss to space, atmospheric adjustments in the form of temperature increase, have responded to the change.

7. Implications for the Northeast
Unique Characteristics
Numerous freshwater ecosystems
Dense concentrations of people
History of intensive land use practices
Extensive Forests
*Climate change has the potential to disrupt the dynamic input/output regime agitating natural freshwater systems through the creation of a variety of feedback mechanisms

8. Effect on Lake Temperature in Lake Champlain
Increased global mean temperature
Increased seasonal variability
Increased cloudiness and precipitation, more runoff
More runoff leads to higher base flow warmer water temp.

9. Zooplankton Microscopic invertebrates
Fill a critical niche in Lake ecosystem
Principle species in Lake Champlain calanoid copepods, cyclopoid copepods, Daphnia, Bosmina, Sididae,and Leptodoridae
Daphnia.
(Carling, et al. 2004)
Calanoid Copepod
Bosmina

10. Trophic Cascades

11. Trophic Cascades
Definition: suppression of prey abundance as a result of predators in a food web.
Factors: Spatial and Temporal
-high spatial heterogeneity
-deviation from linear food chain
-high resource availability and quality

12. Predictors of Zooplankton Biomass and Community Structure
1. CLIMATE
2. Nutrient Concentration
3. Predation
Work in concert to determine lakes trophic state.

13. Population Dynamics Earlier spring warming Sedimentation
Rotifer vs Cladoceran
Photoperiod
Edible algae
Sedimentation

14. Spring Warming

15. Dynamics

16. Sedimentation
Rotifer vs Cladoceran
Clay interactions

17. Food Sources Phytoplankton, main food source
Increases in phytoplankton growth related to concurrent increases in water temperature (Dale and Swartzman, 1984)
Perform at a higher than normal rate of photosynthesis in waters with a higher than optimal temperature

18. Lake Baikal, Siberia- Monitored since 1945
the world’s largest freshwater lake
Monitored since 1945
Dramatic temperature increases
Large size of lake- resistance to temperature changes
Importance of long-term monitoring

19. Phytoplankton Biomass
Chlorophyll a and Secchi discs used to measure phytoplankton biomass
Found to increase 300% since 1979 in Lake Baikal
(Hampton, et al, 2008)

20. Earlier Spring Peak Earlier Spring, high base flow, warmer waters
Allows for earlier first peak in phytoplankton growth
Longer growing season  Overall increase in phytoplankton biomass
- - - Phytoplankton normal conditions, − Phytoplankton in thermally loaded conditions. (Dale, Swartzman, 1984)

21. Phytoplankton & Zooplankton
Herbivorous zooplankton peak follow phytoplankton peak
Larger carnivorous zooplankton feed on herbivorous zooplankton
Earlier zooplankton peak
– phytoplankton, zooplankton (Dale, Swartzman, 1984)

22. Zooplankton Biomass Decreasing Copepods and Rotifers
Increasing Cladocerans
Fewer large cladocerans, more smaller
(Hampton, et al, 2008)

23. Zooplankton Decrease in Biomass
Mean and minimum values decrease with temperature
Maximum values increase  high peak
At Max - High variability in Daphnia at high temperatures due to shorter period and larger amplitude (peak)
(Norberg, DeAngelis. 1995)

24. Why are zooplankton decreasing if phytoplankton are increasing?
Biomass is decreasing
↓ Larger zooplankton species (Daphnia)
↑Smaller zooplankton species (Bosmina)
Warmer water conducive to the growth of…

25. Blue-Green Algae Growth rate ↑ as water warms Concurrent P overloading
↓ Water clarity, ↓ dO2
Leads to ↓ diatoms & green algae
Blue-green lower nutritional value
Most zooplankton feed selectively on others
…Apparent increase of phytoplankton and decrease in zooplankton

26. Predation Migration due to predation Predator migration
insect larvae of the Notonecta
preys on zooplankton in the shallows during the during the day.
At night moves to open water to prey on zooplankton

27. The adult form of the Notonecta also known as the water bug

28. Migration by zooplankton
Zooplankton like Tropocyclops and Polyarhra migrate vertically during day and night.
Tropocyclops (copepod) migrate to the bottom of the lake/pond during the day and at night spread equally in the water
Known as typical migration

29. Migration of zooplankton
Polyarhra moves to the surface during the day and spread out during the night.
Known as reverse migration
Zooplankton migrate to avoid predators like fish which also increases their fitness.
At night zooplankton spread out because night predation is more difficult for predators

30. The abundance of zooplankton in Johnson pond at noon

31. Temperate and oxygen levels of Johnson pond during the day and night
Surface water was warmer during the day than bottom of the pond.
At night water was the same temperature allowing the movement of zooplankton
Oxygen levels where higher on the bottom during the day but at night oxygen levels were found to be higher near the surface.
With increase temperatures zooplankton migration cycle would be altered allowing for opportunities for predation and lower the overall fitness of zooplankton.

32. Predation-comparing warmer/cold water lakes
Ice cover- helps to reduce the predation on zooplankton by shortening the growing season of phytoplankton
Canadian lakes have less predation then Danish lakes which have a warmer climate
Increase temperature will allow a longer time for predation of zooplankton

33. What can we expect in Lake Champlain with an increase in predation?
Increased predation would lead to a decrease in zooplankton abundance and biomass.
Less grazing on phytoplankton and algal biomass should increase
More turbid conditions and greening of lakes
A decline in invertebrates and amphibians

34. Zooplankton community composition determined by two major factors
Predation
Resource limitation
Energy moves in direction of arrow
Source: Lake Champlain Basin Program 2008

35. Predation - What has a more significant impact on zooplankton?
Predators
Resource Availability
How can this be determined?
Manipulate predator populations AND food sources in an existing system

36. Case Study: Vanni 1987 Increased food availability
Phytoplankton levels were raised by elevating available nutrients
Addition of planktivorous bluegill sunfish
Zooplankton populations measured
Cladocerans
Copepods
Rotifers

37. Cladocerans Copepods Rotifers

38. Results Zooplankton density primarily driven by resource limitation
Most species saw population rise as a result of elevated food levels, even with added predators
Species composition significantly affected by predation
All Cladoceran species reached larger mature body size in the absence of sunfish
Average size Cladocerans initiated reproduction was smaller in the presence of predator species

39. Case Study: Elser & Carpenter 1988
Removal of Piscivorous largemouth bass
Addition of planktivorous minnows
Comparison between study lake (Tuesday) and reference lake (Paul) that naturally exhibits manipulated fish populations

40. Results
Paul lake = dashed lines, Tuesday lake= solid line, vertical line = spring manipulation
Source: Elser & Carpenter 1988

41. Results After Manipulation: Shift towards larger mean body size
Before manipulation: larger zooplankton present at low levels
Smaller sized species represent most of biomass
After Manipulation: Shift towards larger mean body size
Higher concentration of larger species than before

42. Invasive Predators
Alosa pseudoharengus
Dreissena polymorpha

43. Case Study: Beisner et al. 2003
Lake Champlain: Invasive Alewife is exploiting the Rainbow Smelt population
Crystal and Sparkling Lake (WI): Invasive Rainbow Smelt is interfering with indigenous Alewife population
Zooplankton data taken before and after the invasion was studied

44. Findings
(D) = Daphnia, (CL) = non-daphnid cladocerans, (CAL) = Calanoid Copepods, (CYC) = Cyclopoid Copepods
Source: Beisner et al. 2003

45. Zebra Mussels
Solid line = Observed impacts, Dotted line = Potential impacts
(+) = Taxa benefitting from zebra mussels, (-) = Taxa exhibiting adverse effects due to zebra mussels
Source: MacIsaac 1996.

46. Possible Impacts on Zooplankton
Reduction in zooplankton biomass
Direct - ingestion of smaller taxa (copepod nauplii)
May alter species composition
Indirect - Filtration of suspended solids and phytoplankton could result in food limitation

47. Conclusions Large zooplankton populations are likely to decrease
Reduce food sources for higher trophic levels
Reduction of species dependent on large zooplankton
Increase in species feeding on small taxa
Significant changes in lake species composition!

49. Recommendations! Long term monitoring in Lake Champlain
Efforts to decrease P loading
Practice best management processes to reduce invasives and further disruption
More $$ for research!!!

50. References
Alain P, Hann D and B. Climate change, diapause termination and zooplankton population dynamics: an experimental and modeling approach. Freshwater Biology, p. 221–235
Beisner, B.E., Ives, A.R., Carpenter, S.R. The Effects of an Exotic Fish Invasion on the Prey Communities of Two Lakes. The Journal of Animal Ecology, (2),
Borer E T, Seabloom I, Shurin J B, Anderson K E, Blanchette C, Broitman B, Cooper SD, Harpen BS. What Determines the Strength of the Trophic Cascade? Ecology Society of America, p
Courture S C, Watzin M C. Diet of Invasive Adult White Perch (Monroe Americana) and their Effects on the Zooplankton Community in Missisquoi Bay, Lake Champlain. Journal of Great Lakes Res P
Dale V H, Swartzman G L. Simulating the Effects of Increased Temperature in a Plankton Ecosystem: A Case Study; Algae as Ecological Indicators, Academic Press, New York; p , 13 fig, 4 tab, 44 ref. Contract No. NRC
Esler, J.J., & Carpenter S.R. Predation-Driven Dynamics of Zooplankton and Phytoplankton Communities in a Whole-Lake Experiment. Oecologia, (1),

51. Genkai-Kato M, Carpenter S R
Genkai-Kato M, Carpenter S R. Eutrophication Due to Phosphorus Recycling in Relation to Lake Morphometry, Temperature and Macrophytes. Ecological Society of America, p
Gyllstrom M, Hansson L A, Jeppesen E, Garcia-Cirado F, Gross E, Irvine K, Kairesalo T. The Role of Climate in Shaping Zooplankton Communities ofShallow Lakes. American Society of Limnology and Oceanography, p
Hampton S E, et al. Sixty years of environmental change in the world’s largest freshwater lake – Lake Baikal, Siberi. Global Change Biology, P
Heyhoe K, et al. Past and future changes in climate and hydrological indicators in the US Northeast. Climate Dynamics, P
Jackson LJ. “A comparison of shallow Danish and Canadian lakes and implications of climate change” Freshwater Biology, P  
Kirk K, Gilbert J J. Suspended Clay and the Population Dynamics of Population Dynamics of Planktonic Rotifers and Cladocerans. Ecology, (5). p
MacIsaac, H.J., (1996). Abiotic and Biotic Impacts of Zebra Mussels on the Inland Waters of North America. American Zoologist, 36 (3),
Meng Zhou, Mark E. Huntley dynamics theory of plankton based on biomass spectra. Marine Ecology Progress Series, p
Molinero JC. Climate control on the long-term anomalous changes of zooplankton communities in the Northwestern Mediterranean. Global Change Biology, 2008. 14 .p
Schmitz O J, Post E, Burns C E, Johnston K M. Ecosystem Responses to Global Climate Change: Moving Beyond Color Mapping. BioScience, p
Norbert J, DeAngelis D. Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrient. Ecological Modeling, (1). P
Sweetman J N, LaFace E, Riihland K M, Smol J P. Evaluating the Response of Cladocera to Recent Environmental Changes in Lakes from the Central Canadian Arctic Treeline Region Arctic, Antarctic, and Alpine Research, (3)p
Vanni M.J. Effects of Food Availability and Fish Predation on a Zooplankton Community. Ecological Monographs, (1),
Verburg P, Hecky R E, Kling H. Ecological Consequences of a Century of Warming in Lake Tanganyika. Science, (5632) p. 505 – 507.