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LAKE-WETLAND LINKAGE AND PERIPHYTON DYNAMICS IN A LAKE SUPERIOR COASTAL WETLAND
Citation:
Morrice, J A., J A. Thompson, A S. Trebitz, J. R. Kelly, AND A M. Cotter. LAKE-WETLAND LINKAGE AND PERIPHYTON DYNAMICS IN A LAKE SUPERIOR COASTAL WETLAND. Presented at 44th Annual International Association for Great Lakes Research Meeting, Green Bay, WI, June 10-14, 2001.
Description:
Tributaries feeding coastal wetlands along the Wisconsin shore of Lake Superior are generally depleted in inorganic nitrogen (TIN) relative to phosphorus (SRP), while Lake Superior is phosphorous depleted and relatively rich in TIN. Within wetlands, mixing of tributary and lake waters results in nutrient conditions ranging from potentially nitrogen limiting (TIN:SRP<15) in zones with high proportions of tributary water to phosphorous limiting (TIN:SRP>15) in zones with high proportions of lake water. We used nutrient diffusing substrates (Control, N-amended, P-amended, N+P-amended) to determine nutrient limitation of periphyton communities in Lost Creek, a dendritic coastal wetland near Cornucopia, WI. Substrates were placed in four locations within the wetland along an axis from the tributary inflow to the opening to the lake. Periphyton response (measured as Chl a) was determined after a three week incubation. Co-limitation (N+P>other treatments) was evident at all locations. In addition, periphyton responded to the nitrogen amendment (N>control) at all locations. There was no evidence of periphyton response to phosphorous enrichment. These results indicate that periphyton communities in coastal wetlands of western Lake Superior respond strongly to nutrient loading and suggest that linkages to adjacent systems, particularly N-rich Lake Superior, are important factors structuring these ecosystems.