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WETLAND MORPHOLOGIC AND BIOGEOGRAPHIC INFLUENCES ON ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS
Citation:
Thompson, J A., J A. Morrice, S L. Batterman, A M. Cotter, G. S. Peterson, AND N. Danz. WETLAND MORPHOLOGIC AND BIOGEOGRAPHIC INFLUENCES ON ALGAL RESPONSES TO NUTRIENT LOADING IN GREAT LAKES COASTAL WETLANDS. Presented at National Benthological Society Annual Meeting, Athens, GA, May 27-31, 2003.
Description:
We are testing the influence of wetland morphology (protected vs. riverine) and biogeography (upper vs. lower Great Lakes) on algal responses to nutrients in Great Lakes Coastal wetlands. Principal components analysis using nutrient-specific GIS data was used to select sites within each of the geomorphic and biogeographic classes that were expected to cover a range of nutrient loading. We selected sites with low and high PCA scores in each class for intensive studies, and measured nutrient chemistry, water column and periphyton chlorophyll, algal community composition, and responses to nutrient amendments at each site. In addition, we measured phytoplankton chlorophyll at four additional sites in each class with intermediate PC scores. Results show that both periphyton and phytoplankton chlorophyll was greater in high vs. low nutrient sites. In both protected and riverine systems, phytoplankton chlorophyll was higher in the lower vs. upper lakes. In the lower lakes, phytoplankton chlorophyll was higher in riverine vs. protected wetlands, while periphyton was greater in protected vs. riverine. There were differences in major algal taxonomic groups between the two geomorphic types and there were differences in the way the algal communities responded to nutrient amendments across sites. This abstract does not necessarily reflect USEPA policy.
Impact Statement: States and Tribes must develop nutrient criteria for all water bodies. Criteria for Great Lakes coastal areas are still in development. Criteria based on across an entire resource or within broad geographic areas may be under or overprotective because the effect of nutrients may be regulated by other factors, such as hydrology or geology. Our research, which is being conducted under U.S. EPA's Aquatic Stressor Framework and associated Nutrient Implementation Plan, is contributing to the science to help develop appropriate nutrient criteria for Great Lakes coastal wetlands.We are testing the influence of wetland morphology (protected vs. riverine) and biogeography (upper vs. lower Great Lakes) on algal responses to nutrients in Great Lakes Coastal wetlands. Principal components analysis using nutrient-specific GIS data was used to select sites within each of the geomorphic and biogeographic classes that were expected to cover a range of nutrient loading. We selected sites with low and high PCA scores in each class for intensive studies, and measured nutrient chemistry, water column and periphyton chlorophyll, algal community composition, and responses to nutrient amendments at each site. In addition, we measured phytoplankton chlorophyll at four additional sites in each class with intermediate PC scores. Results show that both periphyton and phytoplankton chlorophyll was greater in high vs. low nutrient sites. In both protected and riverine systems, phytoplankton chlorophyll was higher in the lower vs. upper lakes. In the lower lakes, phytoplankton chlorophyll was higher in riverine vs. protected wetlands, while periphyton was greater in protected vs. riverine. There were differences in major algal taxonomic groups between the two geomorphic types and there were differences in the way the algal communities responded to nutrient amendments across sites. This abstract does not necessarily reflect USEPA policy.
Impact Statement: States and Tribes must develop nutrient criteria for all water bodies. Criteria for Great Lakes coastal areas are still in development. Criteria based on across an entire resource or within broad geographic areas may be under or overprotective because the effect of nutrients may be regulated by other factors, such as hydrology or geology. Our research, which is being conducted under U.S. EPA's Aquatic Stressor Framework and associated Nutrient Implementation Plan, is contributing to the science to help develop appropriate nutrient criteria for Great Lakes coastal wetlands.