An inland salt marsh is a saltwater marsh located away from the coast. It is formed and maintained in areas when evapotranspiration exceeds precipitation and/or when sodium- and chloride-laden groundwater is released from natural brine aquifers. Its vegetation is dominated by halophytic plant communities. [1]
Inland salt marshes (ISMs) are rare, non-tidal wetlands which form either due to the influence of saline groundwater and proximate springs and seeps [2] [3] or from evapotranspiration exceeding precipitation. [1] Primarily located in the Great Lakes region of the US, they are dominantly composed of salt-tolerant, halophytic plant communities including the invasive Phragmites australis (common reed). [3] Anthropogenic impacts on brine springs have decreased their already low global coverage and have led to their classification as G1 critically imperiled ecosystems. [2] Of note, inland salt marshes are globally occurring, though this article primarily discusses ISMs from the US and Europe.
If vegetation is at all present, ISMs are typically dominated by halophytic vegetative communities, though species-specific composition may vary among marshes. In a study quantifying spatial variability of ISM vegetation, New York ISMs were found to be composed of Phalaris arundinacea (reed canary grass), Typha × glauca , Lythrum salicaria (purple loostrife), and invasive Phragmites australis (common reed). [3] Rapidly invading US ISMs, Phragmites australis has been shown to associate with highly saline areas with short hydroperiods, suggesting high water levels dilute salinity and decrease photosynthetic activity of this halophytic species. [3] Michigan ISMs were found to be mainly composed of E. parvula and S. americanus, with little commonality with New York ISMs. [3]
Vegetation of inland salt marshes have also been shown to reflect environmental conditions. A recently accepted European study provides detailed analyses on species associations with salinity, moisture, light availability, and nitrogen content. Analyses suggest that certain ISM species have specific environmental requirements, and knowledge of which can better inform salt marsh conservation efforts accordingly. [4]
Inland salt marshes can have extremely dynamic and harsh soil chemistry conditions. Much of the marsh is saturated with a layer of sodium chloride, failing to sustain much plant life that can not tolerate such high salinity environments. [2] For halophytic plants which can colonize this harsh soil, nitrogen content is also a limiting factor. This limitation is increased when plants are inundated with water, as higher levels can dilute the soil and reduce availability of nitrate and ammonium sources of nitrogen. [5]
Many studies have also investigated the role of soil chemistry in the productivity and community structures of ISMs. For instance, a study on an Ohio salt marsh found Salicornia europea (common glasswort) increased production when fertilized with nitrogen, and its different growth forms may be induced by varying soil nitrogen concentrations. [6] Conversely, Hordeum jubatum (foxtail barley) and Atriplex triangularis (orache) were found to be limited by another factor other than nitrogen availability. [6] In other words, different species are limited by different factors within an inland salt marsh ecosystem, providing competitive advantages and allowing for the occupation of different niches.
There have also been efforts to apply GIS and remote sensing methods to characterize the soil chemistry of inland salt marshes. [7]
Inland salt marshes are quite rare and have unique conservation needs, yet there is a severe lack of research on these ecosystems.
Protected by the European Natura 2000 network [8] and classified as a G1 category endangered ecosystem, [1] there is a strong need to protect these rare, decreasing ecosystems, yet a lack of available research supports these conservation initiatives. One study aimed to address this gap with a case study in Central Europe; interdisciplinary analysis of various salt marsh conditions suggested that regular flooding of the inland salt marsh with nearby brine, in this case from a nearby health center, could be used to restore endangered inland salt marshes. [9]
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently for years or decades or seasonally for a shorter periods. Flooding results in oxygen-poor (anoxic) processes taking place, especially in the soils. Wetlands are different from other land forms or water bodies due to their aquatic plants adapted to oxygen-poor waterlogged soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods exist for assessing wetland functions and wetland ecological health. These methods have contributed to wetland conservation by raising public awareness of the functions that wetlands can provide. Constructed wetlands are a type of wetland that can treat wastewater and stormwater runoff. They may also play a role in water-sensitive urban design. Environmental degradation threatens wetlands more than any other ecosystem on Earth, according to the Millennium Ecosystem Assessment from 2005.
A fen is a type of peat-accumulating wetland fed by mineral-rich ground or surface water. It is one of the main types of wetlands along with marshes, swamps, and bogs. Bogs and fens, both peat-forming ecosystems, are also known as mires. The unique water chemistry of fens is a result of the ground or surface water input. Typically, this input results in higher mineral concentrations and a more basic pH than found in bogs. As peat accumulates in a fen, groundwater input can be reduced or cut off, making the fen ombrotrophic rather than minerotrophic. In this way, fens can become more acidic and transition to bogs over time.
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.
Phragmites is a genus of four species of large perennial reed grasses found in wetlands throughout temperate and tropical regions of the world.
Montezuma National Wildlife Refuge is a wildlife preserve operated by the United States Fish and Wildlife Service, encompassing part of the Montezuma Swamp at the north end of Cayuga Lake. The 10,004-acre preserve is composed of swamps, pools and channels and is a stopping point for migratory birds. It is the largest contiguous wetland complex in the northeastern United States and comprises a portion of the larger Montezuma Wetlands Complex, which is a partnership between the USFWS, the New York State Department of Environmental Conservation, as well as several other non-profit support organizations.
A tidal creek or tidal channel is a narrow inlet or estuary that is affected by the ebb and flow of ocean tides. Thus, it has variable salinity and electrical conductivity over the tidal cycle, and flushes salts from inland soils. Tidal creeks are characterized by slow water velocity, resulting in buildup of fine, organic sediment in wetlands. Creeks may often be a dry to muddy channel with little or no flow at low tide, but with significant depth of water at high tide. Due to the temporal variability of water quality parameters within the tidally influenced zone, there are unique biota associated with tidal creeks which are often specialised to such zones. Nutrients and organic matter are delivered downstream to habitats normally lacking these, while the creeks also provide access to inland habitat for salt-water organisms.
A tidal marsh is a marsh found along rivers, coasts and estuaries which floods and drains by the tidal movement of the adjacent estuary, sea or ocean. Tidal marshes experience many overlapping persistent cycles, including diurnal and semi-diurnal tides, day-night temperature fluctuations, spring-neap tides, seasonal vegetation growth and decay, upland runoff, decadal climate variations, and centennial to millennial trends in sea level and climate.
An aquatic ecosystem is an ecosystem found in and around a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms—aquatic life—that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic ; lotic ; and wetlands.
California's coastal salt marsh is a wetland plant community that occurs sporadically along the Pacific Coast from Humboldt Bay to San Diego. This salt marsh type is found in bays, harbors, inlets, and other protected areas subject to tidal flooding.
The Titarisios is a river in Thessaly, Greece. It is a major tributary of the Pineios. The river begins at the western slopes of Mount Olympus and flows southwest, then south. It leaves the mountains near the village Sykia, and turns east near the village Vlachogianni. It passes along the town Tyrnavos and flows into the Pineios near the village Rodia. The confluence is at 65 m above sea level. Its total length is 70 km, and for most of its length it contains water throughout the year.
Phragmites australis, known as the common reed, is a species of flowering plant in the grass family Poaceae. It is a wetland grass that can grow up to 20 feet tall and has a cosmopolitan distribution worldwide.
Ficinia nodosa, the knotted club-rush or knobby club-rush, is a rhizomatous perennial in the family Cyperaceae, native to South Africa, Australia, and New Zealand. Widespread in the Southern Hemisphere, Ficinia nodosa grows to between 15 and 220 cm in height. Although it grows best in sandy, salty soil, the plant grows in a wide variety of environments from coastal sand dunes to alpine regions. F. nodosa’s appearance is characterised by dense clusters of long green stems topped with small, rounded flowers often remaining throughout the year.
Brackish marshes develop from salt marshes where a significant freshwater influx dilutes the seawater to brackish levels of salinity. This commonly happens upstream from salt marshes by estuaries of coastal rivers or near the mouths of coastal rivers with heavy freshwater discharges in the conditions of low tidal ranges.
A freshwater marsh is a non-forested marsh wetland that contains shallow fresh water, and is continuously or frequently flooded. Freshwater marshes primarily consist of sedges, grasses, and emergent plants. Freshwater marshes are usually found near the mouths of rivers, along lakes, or are present in low lying areas with low drainage like abandoned oxbow lakes. Unlike its counterpart the salt marsh, which is regularly flushed with sea water, freshwater marshes receive the majority of their water from surface water.
High marsh is a tidal marsh zone located above the Mean Highwater Mark (MHW) which, in contrast to the low marsh zone, is inundated infrequently during periods of extreme high tide and storm surge associated with coastal storms. This zone is impacted by spring tides, which is a bi-monthly lunar occurrence where the high marsh experiences higher inundation levels. The high marsh is the intermittent zone between the low marsh and the uplands, an entirely terrestrial area rarely flooded during events of extreme tidal action caused by severe coastal storms. The high marsh is distinguished from the low marsh by its sandy soil and higher elevation. The elevation of the high marsh allows this zone to be covered by the high tide for no more than an hour a day. With the soil exposed to air for long periods of time, evaporation occurs, leading to high salinity levels, up to four times that of sea water. Areas of extremely high salinity prohibit plant growth altogether. These barren sandy areas are known as "salt pans". Some cordgrass plants do survive here, but are stunted and do not reach their full size.
Low marsh is a tidal marsh zone located below the Mean Highwater Mark (MHM). Based on elevation, frequency of submersion, soil characteristics, vegetation, microbial community, and other metrics, salt marshes can be divided to into three distinct areas: low marsh, middle marsh/high marsh, and the upland zone. Low marsh is characterized as being flooded daily with each high tide, while remaining exposed during low tides.
Juncus roemerianus is a species of flowering plant in the rush family known by the common names black rush, needlerush, and black needlerush. It is native to North America, where its main distribution lies along the coastline of the southeastern United States, including the Gulf Coast. It occurs from New Jersey to Texas, with outlying populations in Connecticut, New York, Mexico, and certain Caribbean islands.
Salt marsh die-off is a term that has been used in the US and UK to describe the death of salt marsh cordgrass leading to subsequent degradation of habitat, specifically in the low marsh zones of salt marshes on the coasts of the Western Atlantic. Cordgrass normally anchors sediment in salt marshes; its loss leads to decreased substrate hardness, increased erosion, and collapse of creek banks into the water, ultimately resulting in decreased marsh health and productivity.
The Moghra Oasis is an uninhabited oasis in the northeastern part of the Qattara Depression in the Western Desert of Egypt. It has a 4 km2 (1.5 sq mi) lake containing brackish water, salt marshes and a swamp with reeds.
Arthrocaulon macrostachyum, synonym Arthrocnemum macrostachyum, is a species of flowering plant in the amaranth family. It is native to coastal areas of the Mediterranean Sea and the Red Sea and parts of the Middle East, where it grows in coastal and inland salt marshes, alkali flats, and other habitats with saline soils.
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