Salt marsh

A salt marsh, saltmarsh or salting, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated by dense stands of salt-tolerant plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments. Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters. They also support terrestrial animals and provide coastal protection. Salt marshes have historically been endangered by poorly implemented coastal management practices, with land reclaimed for human uses or polluted by upstream agriculture or other industrial coastal uses. Additionally, sea level rise caused by climate change is endangering other marshes, through erosion and submersion of otherwise tidal marshes. However, recent acknowledgment by both environmentalists and larger society for the importance of saltwater marshes for biodiversity, ecological productivity and other ecosystem services, such as carbon sequestration, has led to an increase in salt marsh restoration and management since the 1980s. Salt marshes occur on low-energy shorelines in temperate and high-latitudes which can be stable, emerging, or submerging depending if the sedimentation is greater, equal to, or lower than relative sea level rise (subsidence rate plus sea level change), respectively. Commonly these shorelines consist of mud or sand flats (known also as tidal flats or abbreviated to mudflats) which are nourished with sediment from inflowing rivers and streams. These typically include sheltered environments such as embankments, estuaries and the leeward side of barrier islands and spits. In the tropics and sub-tropics they are replaced by mangroves; an area that differs from a salt marsh in that instead of herbaceous plants, they are dominated by salt-tolerant trees.