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NUTRIENT-MEDIATED SHIFTS IN COASTAL WERLAND FOOD FISH STRUCTURE
Citation:
Sierszen, M E., J. C. Brazner, AND J A. Morrice. NUTRIENT-MEDIATED SHIFTS IN COASTAL WERLAND FOOD FISH STRUCTURE. Presented at International Association for Great Lakes Research Annual Meeting, Green Bay, WI, June 10-14, 2001.
Description:
Numerous studies have revealed the importance of algae as an energetic base for wetland food webs. Earlier stable isotope analyses in a Lake Superior coastal werland (Allouez Bay, WI) concluded that the food web was based upon phytoplankton carbon. Recent work in two additional systems (Lost Creeks and Fish Creek wetlands) indicates that not all Lake Superior coastal wetlands are based upon plankton. Our results suggest that epipyton may provide the base for food webs in relatively undisturbes systems, and that nutrient enrichment initiates two changes: 1) the base of the dominant food web pathway shifts from epiphyton toward plankton; 2) the base of the planktonic pathway shifts from detritus to phytoplankton. Total phosphorus concentrations were highest in Allouez Bay wetland, and all wetlands tracked turbidity, pointing to the importance of particle-bound fluvial inputs. Responses of wetland food web structure to nutrients may be mediated by wetland hydrology and goeomorphic type.