Ecological Research on Wetlands and Submersed Aquatic Vegetation

        Wetlands are hydrologically controlled ecosystems essential to estuarine, marine, lacustrine, and riverine productivity.  To improve our understanding of these ecosystems we need information on (1) wetland hydrologic variables/ budgets and their relation to wetland vegetation and nutrient cycling; (2) wetland dynamics and boundary fluctuations; (3) wetland functions and values; and (4) short- and long-term temporal changes.
        Wetland plants may serve as sensitive hydrologic indicators of water-quality parameters such as salinity, turbidity, pH, nutrients; presence of various pollutants; or frequency and duration of inundation.  Submersed aquatic wetlands have many functions including (1) providing habitat for invertebrate species; (2) providing food and (or) shelter for juvenile and adult fish, waterfowl, and other wildlife; (3) retarding flow velocities, stabilizing bottom sediments, and slowing erosion; and (4) oxygenating the water, recycling nutrients and heavy metals.  Decline or disappearance of aquatic plant communities or overgrowth of submersed vegetation under nutrient-enriched conditions is of concern to scientists, ecologists, environmentalists and managers.  The factors affecting distribution and abundance of submersed aquatic vegetation and the effect of submersed aquatic vegetation on water quality are poorly understood.
        Objectives of this project are to (1) determine factors responsible for the changing distribution of submersed macrophyte beds in the tidal Potomac River and other lacustrine and riverine environments; (2) study processes controlling the survival, expansion, and decline of macrophyte populations; (3) determine the effect of submersed macrophytes on water velocity, water quality, and carbon flux; (4) characterize wetland transition zones and relate distribution of vegetation to soils, hydrology and elevation; (5) examine seasonal and long-term changes in wetland ecology as related to changes in environmental parameters including hydrology, water quality and land use; and (6) aid in the development of models that utilize biological, hydrologic, and remote sensing wetland data as part of their primary database.