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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Food Webs
TESTING THE USE OF STABLE ISOTOPES TO IDENTIFY FOOD WEB LINKS IN FRESHWATER RIVERINE COASTAL WETLANDS.
M.S. Pearson, M.F. Moffett, and L.E. Anderson. U.S. EPA, Mid-Continent Ecology Division, Duluth, MN 55804
Twenty riverine coastal wetlands were sampled along the shores of Lake Michigan in 2001 as part of a U.S. EPA Regional Environmental Monitoring and Assessment Program. Fish, invertebrates, periphyton, seston, and macrophytes were collected for 15N and 13C stable isotope analyses. Three to eight benthic macroinvertebrate taxa and four to eight fish species from each wetland were analyzed for 15N and 13C ratios. Analysis of seston, periphyton (artificial and natural substrates) were used to determine whether algae and detritus at the base of the food web occurred in a planktonic versus attached habitat for macroinvertebrates and fish. Four wetlands were selected for testing the ability to use a one-time collection of specimens to discern differences among food webs of riverine wetlands with high, medium and low nutrient and suspended sediment loading. This allowed a test of the hypothesis that riverine systems with high nutrients and suspended sediments support biota primarily using planktonic rather than attached food sources. Benefits of this research include methods to assess beneficial uses of Great Lakes wetlands, and provide regional water quality managers with tools to implement TMDLs for waters impaired by nutrients and suspended sediments. This abstract does not necessarily reflect USEPA policy.
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