daphnia. spike walker. 2005© microscopy uk or their contributors. assessing the ecological risk of...
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Daphnia. Spike Walker. 2005© Microscopy UK or their contributors.
Assessing the Ecological Risk of the Effects of Climate Change on
Zooplankton in Lake Champlain
Alex GibsonMark RasmussenBen ShermanJosh StewartBrittany A. Weldon
ENSC 202Spring, 2009
Increasing water temperatures in Lake Champlain due to climate change will alter zooplankton
populations and cause subsequent food web disruption at higher trophic levels.
Overview
Climate Change Zooplankton in Lake Champlain Trophic cascades and food web Population dynamics Food sources and phytoplankton Predation Invasive species Conclusions & recommendations
Climate Change
The Greenhouse Effect: Visible light passes through the earths atmosphere and is either absorbed or reflected into the atmoshphere.
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.
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.
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
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.
Zooplankton Microscopic
invertebrates Fill a critical niche in
Lake ecosystem Principle species in
Lake Champlain calanoid copepods, cyclopoid copepods, Daphnia, Bosmina, Sididae,and Leptodoridae
(Carling, et al. 2004)
Daphnia.
Calanoid CopepodBosmina
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
Predictors of Zooplankton Biomass and Community Structure 1. CLIMATE 2. Nutrient Concentration 3. Predation
Work in concert to determine lakes trophic state.
Population Dynamics
Earlier spring warmingRotifer vs CladoceranPhotoperiodEdible algae
SedimentationRotifer vs Cladoceran
Spring Warming
Dynamics
Sedimentation
Rotifer vs CladoceranClay interactions
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
Lake Baikal, Siberia- 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
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)
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)
– phytoplankton, - - - zooplankton (Dale, Swartzman, 1984)
Phytoplankton & Zooplankton Herbivorous
zooplankton peak follow phytoplankton peak
Larger carnivorous zooplankton feed on herbivorous zooplankton
Earlier zooplankton peak
Zooplankton Biomass
Decreasing Copepods and Rotifers
Increasing Cladocerans
Fewer large cladocerans, more smaller
(Hampton, et al, 2008)
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)
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…
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
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
The adult form of the Notonecta also known as the water bug
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
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
The abundance of zooplankton in Johnson pond at noon
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.
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
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
Zooplankton community composition determined by two major factors
PredationResource limitation
Energy moves in direction of arrow
Source: Lake Champlain Basin Program 2008
Predation -
What has a more significant impact on zooplankton?PredatorsResource Availability
How can this be determined?Manipulate predator populations AND food
sources in an existing system
Case Study: Vanni 1987
Increased food availabilityPhytoplankton levels were raised by elevating
available nutrients
Addition of planktivorous bluegill sunfish
Zooplankton populations measuredCladoceransCopepodsRotifers
Cladocerans Copepods Rotifers
Results Zooplankton density primarily driven by
resource limitationMost species saw population rise as a result of
elevated food levels, even with added predators
Species composition significantly affected by predationAll Cladoceran species reached larger mature
body size in the absence of sunfishAverage size Cladocerans initiated reproduction
was smaller in the presence of predator species
Case Study: Elser & Carpenter 1988
Removal of Piscivorous largemouth bass
Addition of planktivorous minnowsComparison between study lake (Tuesday)
and reference lake (Paul) that naturally exhibits manipulated fish populations
Results
Paul lake = dashed lines, Tuesday lake= solid line, vertical line = spring manipulation
Source: Elser & Carpenter 1988
Results 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
Invasive Predators
Alosa pseudoharengus Dreissena polymorpha
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
Findings
(D) = Daphnia, (CL) = non-daphnid cladocerans, (CAL) = Calanoid Copepods, (CYC) = Cyclopoid Copepods
Source: Beisner et al. 2003
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.
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
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!
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!!!
References Alain P, Hann D and B. Climate change, diapause termination and zooplankton
population dynamics: an experimental and modeling approach. Freshwater Biology, 2009 54. 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,2003. 72(2), 331-342.
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, 2005. 86.p. 528-537.
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. 2008. 34. P. 485-494.
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; 1984. p 395-427, 13 fig, 4 tab, 44 ref. Contract No. NRC 04-75-222
Esler, J.J., & Carpenter S.R. Predation-Driven Dynamics of Zooplankton and Phytoplankton Communities in a Whole-Lake Experiment. Oecologia,1998 76(1), 148-154.
Genkai-Kato M, Carpenter S R. Eutrophication Due to Phosphorus Recycling in Relation to Lake Morphometry, Temperature and Macrophytes. Ecological Society of America, 2005. 86. p. 210-219.
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, 2005. 50. p. 2008-2021.
Hampton S E, et al. Sixty years of environmental change in the world’s largest freshwater lake – Lake Baikal, Siberi. Global Change Biology, 2008. 14. P. 1947-1958.
Heyhoe K, et al. Past and future changes in climate and hydrological indicators in the US Northeast. Climate Dynamics,
2007. 28. P. 381-407.
Jackson LJ. “A comparison of shallow Danish and Canadian lakes and implications of climate change” Freshwater Biology, 2007. 52. P. 1782-1792
Kirk K, Gilbert J J. Suspended Clay and the Population Dynamics of Population Dynamics of Planktonic Rotifers and Cladocerans. Ecology, 1990. 71(5). p. 1741-1755
MacIsaac, H.J., (1996). Abiotic and Biotic Impacts of Zebra Mussels on the Inland Waters of North America. American Zoologist, 36 (3), 287-299.
Meng Zhou, Mark E. Huntley dynamics theory of plankton based on biomass spectra. Marine Ecology Progress Series, 1997. 159. p. 61-73
Molinero JC. Climate control on the long-term anomalous changes of zooplankton communities in the Northwestern Mediterranean. Global Change Biology, 2008. 14 .p. 11-26
Schmitz O J, Post E, Burns C E, Johnston K M. Ecosystem Responses to Global Climate Change: Moving Beyond Color Mapping. BioScience, 2003. 12. p. 1999-1205
Norbert J, DeAngelis D. Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrient. Ecological Modeling, 1997. 95 (1). P. 75-86.
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, 2008. 40(3)p. 584-591
Vanni M.J. Effects of Food Availability and Fish Predation on a Zooplankton Community. Ecological Monographs, 1987. 57(1), 61-88.
Verburg P, Hecky R E, Kling H. Ecological Consequences of a Century of Warming in Lake Tanganyika. Science, 2003. 301(5632) p. 505 – 507.