Salt Marsh

            The salt marsh is located in a protected, low energy zone just outside the highest beachfront dunes.  It is a depository zone, comprised of thick layers of mud and sand.  Salt marshes are a critical interface between the land and sea.  They provide habitat for fish, birds, and shellfish; protect coastal cities from storms; and they take nutrients out of the water coming from upland areas, which protects coastal bays from over-pollution.  At higher elevations in the upper marsh zone, there is much less tidal inflow, resulting in lower salinity levels.  Soil salinity in thelower marsh zone is fairly constant due to everyday annual tidal flow. Rainfall can reduce salinity and evapotranspiration can increase salinity during dry periods.  As a result, there are microhabitats populated by different species of flora and fauna dependent on their physiological abilities. The flora of a salt marsh is differentiated into levels according to the plants' individual tolerance of salinity and water table levels