Salt marsh


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Salt marsh

A maritime habitat characterized by grasses, sedges, and other plants that have adapted to continual, periodic flooding. Salt marshes are found primarily throughout the temperate and subarctic regions.

The tide is the dominating characteristic of a salt marsh. The salinity of the tide defines the plants and animals that can survive in the marsh area. The vertical range of the tide determines flooding depths and thus the height of the vegetation, and the tidal cycle controls how often and how long vegetation is submerged. Two areas are delineated by the tide: the low marsh and the high marsh. The low marsh generally floods and drains twice daily with the rise and fall of the tide; the high marsh, which is at a slightly higher elevation, floods less frequently. See Mangrove

Salt marshes usually are developed on a sinking coastline, originating as mud flats in the shallow water of sheltered bays, lagoons, and estuaries, or behind sandbars. They are formed where salinity is high, ranging from 20 to 30 parts per thousand of sodium chloride. Proceeding up the estuary, there is a transitional zone where salinity ranges from 20 to less than 5 ppt. In the upper estuary, where river input dominates, the water has only a trace of salt. This varying salinity produces changes in the marsh—in the kinds of species and also in their number. Typically, the fewest species are found in the salt marsh and the greatest number in the fresh-water tidal marsh.

The salt marsh is one of the most productive ecosystems in nature. In addition to the solar energy that drives the photosynthetic process of higher rooted plants and the algae growing on the surface muds, tidal energy repeatedly spreads nutrient-enriched waters over the marsh surface. Some of this enormous supply of live plant material may be consumed by marsh animals, but the most significant values are realized when the vegetation dies and is decomposed by microorganisms to form detritus. Dissolved organic materials are released, providing an essential energy source for bacteria that mediate wetland biogeochemical cycles (carbon, nitrogen, and sulfur cycles). See Biological productivity

The salt marsh serves as a sediment sink, a nursery habitat for fishes and crustaceans, a feeding and nesting site for waterfowl and shorebirds, a habitat for numerous unique plants and animals, a nutrient source, a reservoir for storm water, an erosion control mechanism, and a site for esthetic pleasures. Appreciation for the importance of salt marshes has led to federal and state legislation aimed at their protection.

References in periodicals archive ?
During peak season, billions of mosquitoes start to head north along the Gulf Coast, creating an eerie sound, says Richard Mankin, an acoustics engineer with ARS in Gainesville who is working with Kline on remote detection devices for salt marsh mosquitoes.
The objectives of this project are: (1) to characterize temporal and spatial changes in the species composition, maximum canopy height, shoot density, and percent areal cover of the marsh plant communities in the northern, central, and southern segments of the Tuckerton Peninsula; (2) to investigate the impact of human activities on the system, such as ditching of salt marsh habitat in the northern segment; and (3) to examine key drivers of salt marsh habitat change in the system, such as shoreline erosion and sea-level rise.
As the connectivity of the salt marsh increases, so does the total area in which ants can gather essential resources (e.
This site currently has two visually distinct vegetation communities; a salt marsh community ("salt marsh") dominated by plants similar to those found in Magnolia Marsh and a brackish community ("brackish") dominated by cattail (Typha sp.
Most plots in Salt Marsh strata were surveyed using 4-6 m boats with outboard engines and to facilitate access, conducted within 3 hours of high tide.
In France, salt marsh lamb is a luxury and in Britain, TV chefs are now lauding the product, yet some farmers still struggle to reap the benefits.
Using chiefly historical evidence we have outlined how the salt marsh at Aust and Northwick warths in the Severn Estuary evolved during recent centuries over a frontage of about 4 km in a stepwise manner on a decadal-centennial time scale.
Anyone wishing to join the Coastal Rangers and Dee Wildfowlers, who help to manage to salt marsh and estuary lands, for lunch and a walk into the heart of the estuary should call the visitor centre at Wepre Park to book their place and find out details on meeting places.
For centuries the lower section of the River Team played host to a variety of industries and much of the salt marsh, an important feeding ground for birds and other wildlife like otters, was lost.
CLF provided funds to Local partners in New England interested in restoring salt marsh and rivers.