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EXTRACELLULAR ENZYME ACTIIVTY AS A SURROGATE FOR NUTRIENTS AND NUTRIENT HISTORY IN GREAT LAKES WETLANDS
Hill, B. H., C M. Elonen, T. M. Jicha, AND J A. Thompson. EXTRACELLULAR ENZYME ACTIIVTY AS A SURROGATE FOR NUTRIENTS AND NUTRIENT HISTORY IN GREAT LAKES WETLANDS. Presented at American Society of Limnology and Oceanography, Salt Lake City, UT, February 8-14, 2003.
Great Lakes ecosystems are generally thought to be P-limited, but N-limitation may be more common than previously suspected. N-limitation should be most obvious in freshwater coastal wetlands, where the anaerobic oxidation of organic carbon may be limited by nitrate availability and/or phosphorus enrichment. We tested a suite of oxido-reductase and hydrolytic extracellular enzymes, produced by sediment microbial communities in their processing of organic carbon, as surrogate indicators of nutrient loadings to 24 Great Lakes coastal wetlands. Enzyme activities were compared with water and sediment chemistry, and with a watershed-scale anthropogenic stressor gradient. Phosphatase activity was positively correlated with water and sediment N concentrations; and negatively with water and sediment P concentrations and the watershed stressor gradient. N-acetyl glucosaminidase was positively correlated with P concentrations and the stressor gradient; and negatively correlated with N concentrations. Aminopeptidase activity was negatively correlated with sediment N concentrations. Dehydrogenase activity was positively correlated with sediment N and the watershed stressor gradient. Our results suggest that, at least within regional boundaries, extracellular enzymes produced by sediment microbial communities reflect nutrient loadings to wetlands. This abstract does not necessarily reflect U.S. EPA policy.
SS1.02 CS24 CS38