Notes

Outline

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Great Lakes National Program Office USEPA Monitoring Required by GLWQA  Began in 1983 Current Sampling Includes: Phytoplankton Zooplankton Benthos Physical/Chemical Parameters

Great Lakes National Program Office Focus on Offshore Waters Emphasis on Spatial Coverage Biannual Sampling Spring mixed Summer stratified

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TOPICS Phytoplankton Community Composition, Biomass Deep Chlorophyll Maximum Historical Communities Crustacean Zooplankton Community Composition Size Structure of Community

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Phytoplankton - Conclusions Productivity Similar to Other Upper Lakes - Intermediate Between Superior and Michigan Diatoms Dominant Group in Spring Summer/Fall dominated by Chrysophytes, Diatoms North/South Differentiation? Summer Community Similar to Superior

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DCM Comparison: Shade Adaptation No Increase in Biomass Improved Nutrient Status Higher Nutrients at Depth? Shade Adaptation Increase in Biomass Improved Nutrient Status Higher Nutrients at Depth

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Historical Summer Phytoplankton Communities Greater Proportion of Diatoms, Compared to Michigan Indicative of lesser degree of historical eutrophication? Non-Diatoms Mostly Chrysophytes Slightly Lower Levels of Biovolume

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Zooplankton - Conclusions Community Makeup: Spring: Diaptomid copepods dominate Copepodites abundant Summer: D. galeata mendotae, Diaptomids dominate Biomass Higher in Summer High Degree of Spatial Homogeneity

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Mills et al. 1987

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Zooplankton - Conclusions Majority of Individuals Small (< 1 mm) Majority of Biomass (64.7%) From Large Individuals Mean Size of Community Indicative of High Piscivore/Planktivore Ratio

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DCM - Conclusions Deep Chlorophyll Maximum Probably Due To: Change in configuration of chloroplast Shade adaptation No Evidence Of Biomass Maximum At Depth Some Evidence Of Improved Nutrient Status At Depth

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