A marsh salt or saltmarsh , also known as coastal salt marsh or tidal swamps, is a coastal ecosystem in the upper coastal intertidal zone between mainland and open sea waters or brackish water. which are regularly overrun by tides. It is dominated by salt-intensive plant-solid stands such as plants, grass, or low shrubs. This plant comes from the mainland and is essential for salt swamp stability in traps and sediment binding. Salted swamps play a major role in aquatic food webs and nutrient delivery to coastal waters. They also support terrestrial animals and provide coastal protection.
Video Salt marsh
Basic information
Salt swamps occur on low-energy coastlines in temperate and high temperatures that can be stable or emerging, or drown if sedimentation rates exceed the rate of decline. Generally this coastline consists of mud or sand plains (also known as tidal plains or abbreviated with mud) maintained with sediment from streams of rivers and streams. These typically include sheltered environments such as embankments, estuaries and the underside of the islands of barrier and saliva. In the tropics and sub-tropics they are replaced by mangroves; a different area of ​​salt marsh that is not a herbaceous plant, they are dominated by salt tolerant trees.
Most salt marshes have low topography with low elevation but a very large area, making them very popular for the human population. Salt salt lies between different landscapes based on their physical and geomorphological arrangements. Swamp landscapes such as delta swamp delta, estuaries, rear-obstructions, open beaches, embayments and drowning swamp swamps. Delta swamps are associated with major rivers where many occur in southern Europe such as the Camargue, France in the delta of the Rhone or the Ebro delta in Spain. They are also widespread in the Mississippi Delta River in the United States. In New Zealand, most salt marshes occur in the head of the estuary in areas where there is little wave action and high sedimentation. These swamps are located in Awhitu Regional Park in Auckland, Muara Manawatu, and the Avon-Heathcote Estuary in Christchurch. Back-barrier swamps are sensitive to re-formation of obstacles on land side they have formed. They are common in most of the east coast of the United States and the Frisian Islands. Broad and shallow beach ambulances can store salt marshes with examples including Morecambe Bay and Portsmouth in the UK and Bay of Fundy in North America.
The salt marshes are sometimes included in the lagoon, and the difference is not too obvious; Venetian Lagoon in Italy, for example, consists of animal species and/or living organisms that belong to this ecosystem. They have a major impact on the region's biodiversity. The salt swamp ecology involves a complex food network that includes primary producers (vascular plants, macroalgae, diatoms, epiphytes, and phytoplankton), major consumers (zooplankton, macrozoa, mollusk, insects), and secondary consumers.
Low physical energy and high grass provide protection for animals. Many sea fish use salt marshes as their children's care lands before they move into open water. Birds can raise their children among tall grasses, as swamps provide shelter from predators and abundant food sources including fish trapped in ponds, insects, shells, and worms.
Maps Salt marsh
Worldwide events
Saltmarshes in 99 countries (basically worldwide) are mapped by Mcowen et al. 2017. A total of 5,495,089 acres of saltmarsh mapped in 43 countries and territories are represented in the Geographic Information Systems polygon shapefile. This estimate is at a relatively low end estimate (2.2-40 Mha). The world's most extensive Saltmarsh is found outside of the tropics, mainly including low-lying, ice-free shores, bays and North Atlantic estuaries that are well represented in their global polygon data set.
Formation
The formation begins when the elevation elevation of the tidal relative to the sea surface with the addition of sediment, and then the rate and duration of tidal flood decreases so that the vegetation can colonize on the open surface. The arrival of pioneer species propagules such as seeds or rhizome parts combined with the development of conditions suitable for germination and its formation in the colonization process. When rivers and streams arrive at a low gradient of the tidal plains, the discharge rate is reduced and the suspended deposits settle to the tidal flat surface, aided by the backwater effect of the rising tide. Blue-green algae algae algae can repair silt and clay sediment particles into a sticky shell on contact that can also increase the resistance of sediment erosion. This helps the process of sediment increase to allow species of colonization (eg, Salicornia spp.) To grow. These species retain the sediments carried from the tides around their stems and leaves and form low muddy mounds that eventually coalesce to form a precipitating porch, whose growth is aided by sub-surface root tissue that binds sediment. Once the vegetation is formed on the sedimentation porch, the sediment is more trapped and the accretion can allow rapid growth of the swamp surface so that there is a rapid decrease associated with the depth and duration of tidal flooding. Consequently, competitive species that prefer a higher elevation relative to sea level can inhabit the area and often succession of growing plant communities.
Tidal floods and vegetation zoning
Coastal salt marshes can be distinguished from terrestrial habitats by daily tidal flows that occur and continuously flood the area. This is an important process in delivering sediment, nutrients and water supply to marsh plants. At higher altitudes in the upper swamp zone, there is less tidal influx, so the salinity level is lower. The soil salinity in the lower swamp zone is fairly constant due to annual daily tidal flow. However, in the upper swamp, variability in salinity is indicated as a result of less frequent floods and climate variations. Rainfall can reduce salinity and evapotranspiration can increase levels during dry periods. As a result, there are microhabitats inhabited by various types of flora and fauna that depend on their physiological abilities. The flora of the salty swamp is divided into levels corresponding to the individual tolerance of the plant to the salt and water levels. Vegetation found in water should be able to withstand high salt concentrations, periodic immersion, and a number of water movements, while plants deep in the marshland can sometimes experience dry and low nutritional conditions. It has been found that upper swamp zones limit species through competition and lack of habitat protection, while lower swamp zones are determined through the plant's ability to tolerate physiological stresses such as salinity, submerged water and low oxygen levels.
The New England salt marsh is subject to strong tidal influences and exhibits different zoning patterns. In low swamp areas with high tidal floods, monocultures of fine cordgrass, Spartina alterniflora dominate, then go ashore, salt straw zones, spartina patens, black rush, spartina patens Juncus gerardii and bushes frutescens seen respectively. All of these species have different tolerances that make different zones along the marsh most suitable for each individual.
The diversity of plant species is relatively low, since the flora should be salt tolerant, complete or partial immersion, and an anoxic sludge substrate. The most common salt marsh plants are glassworts ( Salicornia spp.) And cordgrass ( Spartina spp.), Which has worldwide distribution. They are often the first plants to hold in the mud and start an ecological succession into a salt marsh. Their shoots lift the main stream from pairs over the mud surface while their roots spread to the substrate and stabilize the sticky mud and carry oxygen into it so other plants can build themselves as well. Plants such as sea lavender ( Limonium spp.), Banana king ( Plantago spp.), And various sediments and groves grow so mud has been overgrown by pioneer species.
Salted swamps are quite active in photosynthesis and are highly productive habitats. They serve as a deposit for large amounts of organic matter and full of decomposition, which feeds the food chain of broad organisms from bacteria to mammals. Many halophytic plants such as cordgrass are not grazed at all by higher animals but die and decompose into food for micro-organisms, which in turn become food for fish and birds.
Sediment traps, increments, and tidal roles
Factors and processes affecting the rate and spatial distribution of sediment increase in many salt marshes. Sediment buildup can occur when swamp species provide a surface for sediments to adhere to, followed by deposition to the swamp surface when deposits of shale at low tide. The amount of sediments attached to salt marsh species depends on the species of swamp species, the proximity of species with sediment supply, the amount of plant biomass, and species elevation. For example, in the study of Eastern Chongming Island and the tidal swamps of Jiuduansha Island at the mouth of the Yangtze River, China, the amount of sediments attached to Spartina alterniflora species, Phragmites australis, and Scirpus mariqueter decreases with distance from the highest level of suspended sediment concentration (found on the edge of the swamp adjacent to tidal rivers or mud plains); decreases with the species at the highest elevation, which experiences the lowest frequency and tidal inundation depth; and increases with increasing plant biomass. Spartina alterniflora , which has the most sediment attached to it, can contribute &> 10% of total sediment surface swamp by this process.
Salt swamp species also facilitate sediment increase by decreasing current velocity and encouraging sediment to escape from suspension. Current velocity can be reduced because the high swamp species stem induces hydraulic drag, with the effect of minimizing sediment re-suspension and encouraging precipitation. The measured concentration of suspended sediments in the water column has been shown to decrease from open water or tidal rivers adjacent to the edge of the swamp, to the inland swamp, probably as a result of direct deposition to the swamp surface by the influence of the swamp canopy..
Flooding of pools and sediments on swamp surfaces is also aided by tidal rivers which are a common feature of salt marshes. Their distinctive dendritic and winding forms provide a way to tide up and flood the surface of the swamp, and to drain water, and they can facilitate higher sediment deposition rates than salt marsh that borders the open sea. Sediment deposition is correlated with sediment size: rough sediments will precipitate at higher elevations (closer to rivers) than finer sediments (farther from the river). Sedimentary sizes are also often correlated with certain trace metals, and may be tidal tributaries can affect the distribution and concentration of metals in salt marshes, which in turn affect the biota. However, salt marshes do not require tidal water to facilitate sediment flux above its surface although salt morphology with this morphology seems rarely studied.
Elevation of swamp species is important; the species in the lowlands experience longer and more frequent tidal floods and therefore have more opportunity for sediment deposition to occur. Species at higher altitudes may benefit from the possibility of greater flooding at the highest tide when increased water depth and marsh surface flows can penetrate into the marsh interior.
Human impact
The beach is a natural feature that is very attractive to humans through its beauty, resources, and accessibility. In 2002, more than half the world's population was estimated to live within 60 km of the coastline, making the coastline extremely vulnerable to human impacts of daily activities that put pressure on the surrounding natural environment. In the past, salt marshes were considered 'coastal' coastal land, causing huge losses and changes in these ecosystems through land reclamation for agriculture, urban development, salt production and recreation. Indirect effects of human activities such as nitrogen loading also play a major role in salt marshy areas. Salted swamps can suffer dieback in high swamps and die in low swamps.
Land reclamation
The reclamation of farmland by converting swampland to the highlands has historically been a common practice. Ditches are often built to allow for changes in land change and provide further flood protection inland. In recent times the intertidal flats have also been reclaimed. Over the centuries, cattle like sheep and cattle graze on the fertile salt marsh soil. Land reclamation for agriculture has resulted in many changes such as shifting vegetation structures, sedimentation, salinity, water flow, loss of biodiversity and high nutritional inputs. There have been many attempts to combat this problem, for example, in New Zealand, cordgrass Spartina anglica was introduced from England to the mouth of the Manawatu River in 1913 to try and reclaim the estuary land for agriculture. The structural shift from flat tides to pasture results from increased sedimentation and cordgrass extended out to other estuaries around New Zealand. Indigenous plants and animals struggle to survive when non-natives compete with them. Efforts are now being made to eliminate this cordgrass species, as the damage is slowly recognized.
At the mouth of Blyth in Suffolk in eastern England, the reclaimed middle estuaries (Angel and Bulcamp swamps) abandoned in 1940 have been replaced by tidal flats with compacted soil from agricultural use crushed with a thin layer of mud. Small vegetation colonization has occurred in the last 60-75 years and has been associated with a combination of too low surface elevations for pioneer species to flourish, and poor drainage of compacted agricultural soils that act as aquaclude. This natural terrestrial soil needs to be adjusted from fresh interstitial water to salt water with changes in chemical and soil structure, accompanied by sediment deposition of fresh estuaries, before salt marsh vegetation can be formed. The vegetation structure, species richness, and plant community composition of the naturally regenerated salt marshes on reclaimed farmland can be compared with adjacent reference salt swamps to assess the success of swamp regeneration.
Upstream Agriculture
Upstream cultivation of the salt marsh can introduce increased sludge and increase the rate of primary sediment increase in the tidal plains, so that pioneer species can spread further into the plains and grow rapidly upward from the tidal inundation levels. As a result, the swamp surface in this regime may have large cliffs at the edge of the sea. At the mouth of Plum Island, Massachusetts (USA), the stratigraphic core reveals that during the 18th and 19th centuries, the swamps were getting closer to the subtidal and mudflat environments to increase the area from 6 km 2 to 9 km < > 2 after European settlers deforest land uptream and increase sediment supply rates.
Urban development and loading of nitrogen
The conversion of swamp land to highlands for agriculture in the past century has been overshadowed by conversions for urban development. Coastal cities around the world have penetrated into the former salt marshes and in the US, the growth of cities looks to the salt marshes for landfills. Pollution of coal from organic, inorganic, and toxic substances from urban development or industrialization is a world problem and sediments in salt marshes can counteract this pollution with toxic effects on flower and fauna species. The urban development of salt marshes has been slowing since around 1970 due to increased awareness by environmental groups that they provide useful ecosystem services. They are a very productive ecosystem, and when net productivity is measured in <<> - yr -1 they are only matched by tropical rain forests. In addition, they can help reduce wave erosion on sea walls designed to protect lowland areas from wave erosion.
De-naturalizing salinity marsh land boundaries from urban or industrial areas can have a negative effect. In the estuary of Avon-Heathcote/Ihutai, New Zealand, species abundance and physical properties of the surrounding margins are strongly linked, and the majority of salt marshes are found alive along areas with natural boundaries at Avon and Heathcote river outlets; on the contrary, artificial margins contain a bit of swamp vegetation and restrict land retreats. The remaining swamps around these urban areas are also under enormous pressure from the human population due to human-induced nitrogen enrichment entering this habitat. The loading of nitrogen through human use indirectly affects salt marshes causes a shift in vegetation structure and invasion of non-native species.
Human impacts such as waste, urban runoff, agricultural and industrial waste flow into the swamps from nearby sources. The salty swamps are of limited nitrogen and with the increasing levels of nutrients entering the system from anthropogenic effects, plant species associated with salt marshes are being restructured through changes in competition. For example, the New England salty swamps have shifted vegetation structures where S. alterniflora are spreading from the lower swamps where most are in the upper swamp zone. In addition, in the same marshes, reed Phragmites australis has attacked the developing areas into the lower swamps and become the dominant species. P. australis is an aggressive halophyte that can attack large areas of disruption that defeat native plants. The loss of biodiversity is not only visible in the collection of plants but also in many animals such as insects and birds as their habitats and food sources are changed.
Sea level rise
Due to the melting of the Arctic sea ice and the thermal expansion of the oceans, as a result of global warming, sea levels began to rise. As with all coastlines, this increase in water levels is thought to have a negative impact on salt marshes, by flooding and eroding them. Sea level rise causes a more open water zone in the salt marsh. These zones cause erosion along the edges, further eroding the swamp into open water until the entire swamp is destroyed.
Mosquito control
Earlier in the 20th century, it was believed that drying salt marshes would help reduce mosquito populations. In many locations, especially in the northeastern United States, residents and local and state agencies dug straight ditches deep into the marshes. The end result, however, is the depletion of the killing habitat. The killifish is a predator of mosquitoes, so the loss of habitat actually causes the mosquito population to be higher, and negatively impacts the swamp birds that prey on killifish. These trenches can still be seen, despite attempts to fill the trenches.
Herbivorous crabs and bioturbation
Increased nitrogen uptake by swamp species into their leaves can encourage higher long-term leaf growth rates, and increase crab herbivorous levels. Crabs digging Neohelice granulata often visit the Atlantic salt marshes where high density populations can be found among populations of swamp Spartina densiflora and Sarcocornia macaques perennis . In the Mar Chiquita lagoon, north of Mar del Plata, Argentina, Neohelice granulata herbivores increased in response to increased nutritional value of the fertilized leaves Spartina densiflora > plot, compared to unfertilized plots. Regardless of whether the plot is fertilized or not, grazing by Neohelice granulata also reduces the length of leaf-specific leaf growth rates in summer, while increasing their specific aging rate. This may have been helped by increased effectiveness of the fungus in the wound left by the crabs.
The Cape Cod salt marshes, Massachusetts (USA), experienced the death-and-death banks of Spartina spp. (cordgrass) that has been associated with herbivores by crab Sesarma reticulatum . At 12 Cape marsh salt sites surveyed, 10% - 90% of the river banks are dying from cordgrass in association with highly deforested substrates and high density crab crabs. The population of Sesarma reticulatum increased, possibly as a result of degradation of coastal food networks in the region. The deforested areas left by the intense grazing by the Sãmma reticulatum in Cape Cod are suitable for occupation by crabs digging again, Uca pugnax , which is unknown to consume live macrophytes.. The intense bioturbation of salt marsh sediments from these crab excavation activities has been shown to dramatically reduce the success of Spartina alterniflora and Suaeda maritima seed germination and endurance of established seedlings, both with burials. or the exposure of seeds, or the removal or burial of planted seedlings. However, bioturbation by crabs can also have a positive effect. In New Zealand, Helice crassa tunnel mud crabs have been given the magnificent name of the 'ecosystem engineer' because of its ability to build new habitats and alter nutritional access to other species. Their burrows provide a path for transporting dissolved oxygen in the burrow water through oxide sediments from the burrow wall and to surrounding anoxic sediments, which creates the perfect habitat for special nitrogen cycling bacteria. This nitrate reduces (denitrifying) the bacteria by rapidly consuming dissolved oxygen into the burrow wall to create a thinner layer of oxide mud than that on the surface of the mud. This allows direct diffusion pathways for the export of nitrogen (in the form of nitrogen gas (N 2 )) into the watered tide.
Recovery and management
The perception of bay salt swamps as coastal 'deserts' has since changed, recognizing that they are one of the most biologically productive habitats on earth, rivaling the tropical rainforest. The salt marshes are ecologically important to provide habitat for indigenous migratory fish and act as shelter food and care. They are now protected by law in many countries to preserve these important ecological habitats. In the United States and Europe, they are now given high-level protection by the Water Law and Habitat Rules respectively. With the impact of this habitat and the importance now being realized, growing interest in restoring the salt marshes, through managed retreats or land reclamation has been established. However, many Asian countries such as China still recognize the value of swamp land. With their growing population and intense developments along the coast, the value of the salt marshes tends to be neglected and the land continues to be reclaimed.
Bakker et al. (1997) suggest two options available to restore the salt marshes. The first is to abandon all human intervention and leave the salt marsh to complete its natural development. The types of restoration projects are often unsuccessful because vegetation tends to struggle to return to its original structure and the natural tidal cycle shifts due to land changes. The second option is suggested by Bakker et al. (1997) is to restore destroyed habitat into a natural state either on the original site or as a substitute on a different site. Under natural conditions, recovery may take 2-10 years or even longer depending on the nature and degree of disturbance and relative maturity of the swamp involved. Marshes in their pioneering development phase will recover faster than mature swamps as they often first colonize the soil. It is important to note that restoration can often be accelerated through re-planting of native vegetation.
This latter approach is often the most common and is generally more successful than letting the area recover naturally. The salt marshes in Connecticut state in the United States have long been a lost territory to be filled and dredged. In 1969, the Tidal Wetlands Act was introduced which stopped this practice, but despite the introduction of the action, the system was still degrading due to changes in tidal flows. One area in Connecticut is the swamps on Barn Island. These swamps are curated and then seized with brine and brackish salt during 1946-1966. As a result, marshs shifted into freshwater states and became dominated by invasive species P. australis, Typha angustifolia and Tatif latifolia having few ecological connections to the area.
In 1980, a recovery program was implemented that has been running for over 20 years. The program aims to reconnect the swamps by restoring the tidal flow along with the ecological functions and swamp characteristics back to its original state. In the case of Barn Island, the decline of invasive species has begun, rebuilding tidal vegetation along with animal species such as fish and insects. This example highlights that it takes time and great effort to restore the salt system effectively. Time in the swamp recovery may depend on the stage of swamp development; type and level of disturbance; geographical location; and environmental and physiological stress factors for flora and fauna associated with swamps.
Although much effort has been made to restore the salt marshes around the world, more research is needed. There are many setbacks and problems associated with swamp restoration that require careful long-term monitoring. Information on all components of the salt marsh ecosystem should be understood and monitored from the effects of sedimentation, nutrition, and tidal, on behavioral patterns and tolerance of flora and fauna species. Once we have a better understanding of this process and not just locally, but on a global scale, we can then suggest better and more practical management and restoration efforts that can be used to preserve our precious swamp and return it to its original state.
While humans are located along the coastline, there will always be the possibility of human disturbance even though some restoration efforts we plan to implement. Dredging, pipelines for offshore oil resources, road construction, accidental spills of poison or simply carelessness are examples that will for some time now and in the future be a major influence of salt degradation degradation.
In addition to restoring and managing salt marsh systems based on scientific principles, opportunities must be taken to educate the public about biological importance and their purpose as functioning as a natural buffer for flood protection. Since salt marshes are often located next to urban areas, they tend to receive more visitors than remote wetlands. By physically seeing the swamp, people are more likely to notice and be more aware of the environment around them. An example of public involvement occurred at the Famosa Slough State Marine Area in San Diego, where groups of "friends" worked for more than a decade in an effort to prevent the area being developed. Finally, a 5-hectare site was purchased by Kota and the group working together to restore the area. The project involves the taking of invasive species and replanting with indigenous people, along with public talks to other local residents, frequent bird walks and clean-up events.
Research method
There are a variety and combination of methodologies used to understand the dynamics of hydrology in salt marshes and their ability to trap and accumulate sediment. Sediment traps are often used to measure the level of marsh surface accretion when short-term deployment (eg less than a month) is required. This circular trap consists of pre-weighing filters that anchored to the swamp surface, then dried in the laboratory and reconsidered to determine the total deposited sediment. For long-term studies (eg, over a year), researchers may prefer to measure sediment increase with a marker horizon plot. The marker horizon consists of minerals such as feldspars grown at known depths in the wetland substrate to record the increase in substrate over it over long periods of time. To measure the amount of suspended sediment in the water column, manual or automatic tide samples can be poured through a pre-weighing filter in the laboratory then dried to determine the amount of sediment per volume of water. Another method to estimate suspended sediment concentration is to measure water turbidity using an optical backscatter probe, which can be calibrated to water samples containing suspended sediment concentrations known to establish a regression relationship between the two. Marsh surface elevation can be measured by stadia rod and transit, electronic theodolite, Kinematic Real-Time Global Position Determination System, laser level or electronic distance meter (total station). The dynamics of hydrology include the depth of water, measured automatically with a pressure transducer, or with marked poles, and water velocity, often using electromagnetic flow meters.
See also
References
External links
- Friends of the Slough Famosa
- Geography resources for schools
- Johnson, CY (2006). The cause is sought when the swamp turns into a barren flats. The Boston Globe.
- Sea Study Area operated by Hempstead City: Department of Conservation & amp; The water channel, located in Oceanside, New York, USA
- New England Sudden Wetlands
- The Salt Marsh Nature Center is located in the Brooklyn Sea Park section of New York, USA
Source of the article : Wikipedia
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