| Benthic invertebrates, emerging insects, sedimentation patterns, and biogeochemical cycles were examined to determine the biological and physical function of three morphologically distinct, Great Lakes wetland-estuarine systems. These systems included a deltaic, riverine wetland, a drowned river valley wetland, and an impounded lake/wetland system.; Inundation of the deltaic wetland by the Peshtigo River resulted in a gradient of various physicochemical parameters (e.g., dissolved oxygen, temperature) across the wetland that suggested water from the wetland was mixing with riverine water creating wetland interior and wetland edge zones. Benthic invertebrate abundance, biomass, production, and diversity were greatest at the wetland edge. Similarly, emerging insect abundances and biomass were also greatest at the wetland edge. This was attributed to higher concentrations of dissolved oxygen, the presence of a diverse community of aquatic plants, and delivery of riverine organic matter (i.e. phytoplankton) and revealed the importance of this area to wetland organisms (i.e. birds, fish) that feed upon invertebrates.; Sedimentation patterns from 210Pb and 137Cs profiles in the three systems showed that the Muskegon Lake system, a combined impounded lake and wetland system, trapped approximately 30% of the material flowing through it, while the wetland trapped an estimated 60%. The Kewaunee wetland proved to be the second most effective, trapping 20% of the annual river sediment load flowing through it. Finally, the Peshtigo was the least effective, trapping 4% of the material flowing through it.; The Peshtigo wetland was a minor sink for phosphorus, and was more likely transforming dissolved forms into particulate forms that were transported out into Green Bay. The Peshtigo wetland was also a source of carbon to Green Bay through exports of dissolved and particulate organic carbon. Finally, the Peshtigo wetland was a sink for nitrogen, removing an estimated 40% of nitrogen entering the system. |
