9412089 Wiegert This project will study the transport and transformation of inorganic and organic materials carried from the land into the sea by the five major coastal rivers of Georgia. Each river differs in landscape characteristics, geological setting, flow rate, inorganic and organic loading, and pH, but they are confined within a 120 mile segment of coast and, thus, share similar temperature, rainfall, and tidal regimes. These rivers offer a unique opportunity for the comparative ecological study of the impact of the land, via rivers, on the nearshore ocean and of the ocean, through tidal flooding, on the riparian and ocastal wetlands. The first pahse of these studies will focus on 1) measuring the hyprodynamic characteristics of the rivers and estuaries that are necessary for understanding and quantifying the flux of materials and 2) measuring chemical and physical changes in concentrations and bioactivity of constituents as they pass through distinct communities. A series of laboratory and field experiments to further extend knowledge of the interaction of land, river, sea and riparian and coastal wetlands are also planned. Modeling will be an integral part of all phases of the work. Simple one-compartment models will be used to guide the selection of samples and sites for the component measurements. Multicomponent, mosaic and landscape/watershed models will be used to integrate all phases of the work on fluxes and modifications. Important parameters will be identified on the basis of model sensitivity analysis and appropriate data gathered to reduce the error in parameter evaluation. Specifically, measurements will be made it the kinds, amounts, and metabolic activity of materials carried from above the land/sea margin to the near coastal zone. Associated with the is effort, the hydrodynamic processes repsonsible for transport will be addressed. Field experimetns will be done to ascertain fate of materials as water is displaced out of the estuary onto and off of the major vegetational subsystems. Laboratory experiment/analysis will be em;ployed to examine details of material processing that cannot be observed or measured in the field. Materials studied will include the suspended load of inorganic particles, the dissolved compounds of nitrogen, phosphorous (both inorganic and organic forms) and silica, and the organic carbon compounds. Results will proved useful at several levels, from that of basic research in marine science, through coastal zone management, to the level of global change, predicting impact on the interaction of land and sea in the boudary area regarded as the land/sea margin.
