Salt Marsh

    Salt marshes are wetlands that are juxtaposed with a body of salt water. Oceans and inland salt flats meet fresh water lakes and rivers which have fluctuating levels. This causes a cycle of flooding and varying salinity. Not all plants survive in these conditions. As a result, salt marshes are not very diverse. 

    Salt marshes are created by deposition of detritus. When water flows slowly, sediment settles out building up the soil level.  The soil is rich with nutrients but floods with salt water which recedes in some areas but not others. Anoxia then occurs because the roots cannot get oxygen from saturated soil. Plants with adaptions to tolerate salinity and flooding thrive with little competition leading to zonation in the marsh. 

    Salt marshes are found on every continent but Antartica. In North America, there are no salt marshes on the Pacific coast because the waves are too strong. There are some on the Atlantic coast and near the Great Salt Lake. 

    All salt marshes have algae, plants and animals. The algae is in the water with the cyanobacteria in the benthic stratum. Plants include grasses on land and weeds in the water.  Animals include insects, reptiles, fish, birds, and mammals. The animals and plants are adapted to conditions in the salt marsh. When these conditions are changed by water management every specie is affected.  

    In the Everglades, the water flow is diverted for human use. The salinity increases which reduces fresh water and estuarine habitat. This reduces diversity and increases zonation. 

    The Great Salt Lake and Jamaica Bay have been invaded by phragmites, a reed that competes with native grasses. This reed is tall and does not break down when it dies which means less light for the short grasses and less room for small mammals. Phragmites reduces diversity. 

    Salt marshes are special habitats that need our protection!