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Low marsh
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.
Tall-form Spartina alterniflora (Smooth Cordgrass) is the dominant vegetative species in low marsh areas. S. alterniflora is a native marsh species that is adapted to salt marsh habitat and found along the eastern seaboard of North America, along the coast of Washington, and along the Gulf of Mexico. This tall, warm-season grass grows in frequently inundated and areas with high salinity. This species provides shelter and cover for Fiddler crabs (Uca pugnax), ribbed mussels (Geukensia demissa), waterfowl, wading birds, shorebirds, muskrats, and commercially important fish and shellfish. S. alterniflora contributes to the fight against shoreline erosion by providing soil stabilization and improves water quality by filtering toxic material, such as heavy metals, from the water column.
Salt marshes are very productive ecosystems and provide many ecosystem services including carbon cycling, nitrogen cycling, and coastal flood protection.
Coastal infrastructure is vulnerable to flooding from sea level rise, storms, and land subsidence. Salt marshes help to mitigate effects of flooding by directly buffering coastlines and dissipating waves. They are some of the many types of natural coastal landforms that are widely recognized as barriers to waves and tidal flows. Marsh vegetation causes wave attenuation and may account for up to 60 percent of wave reduction. Marsh plants also improve soil stability, which decreases soil erosion.
Salt marshes and other coastal wetland ecosystems play an important role in the global biogeochemical cycle, especially in the carbon and nitrogen cycles.
Coastal wetlands, such as salt marshes, can sequester carbon at a rate up to ten times that of a mature tropical forest. Through photosynthesis, marsh vegetation capture large amounts of carbon dioxide from the atmosphere. This carbon is stored in plant tissues and soil for hundreds or thousands of years. Coastal salt marshes can sequester about 210 grams of carbon per meter squared per year, which is 2-5 times more carbon per equivalent area than tropical forests.
Eh potential, the energetic favorability of a reaction, is the lowest in low marsh. Eh potential indicates the potential for carbon loss via oxidation into the atmosphere as carbon dioxide. Therefore, the low marsh may have the lowest carbon dioxide emissions compared to other parts of the marsh platform.
Both nitrification and denitrification occur in salt marshes. In nitrification, ammonium is oxidized to nitrite, then nitrite is oxidized to nitrate. In denitrification, organic matter is oxidized using nitrate as a terminal electron acceptor. Denitrification is highest in the low marsh. Nitrogen recycling is the lowest in the low marsh.
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Low marsh AI simulator
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Low marsh
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.
Tall-form Spartina alterniflora (Smooth Cordgrass) is the dominant vegetative species in low marsh areas. S. alterniflora is a native marsh species that is adapted to salt marsh habitat and found along the eastern seaboard of North America, along the coast of Washington, and along the Gulf of Mexico. This tall, warm-season grass grows in frequently inundated and areas with high salinity. This species provides shelter and cover for Fiddler crabs (Uca pugnax), ribbed mussels (Geukensia demissa), waterfowl, wading birds, shorebirds, muskrats, and commercially important fish and shellfish. S. alterniflora contributes to the fight against shoreline erosion by providing soil stabilization and improves water quality by filtering toxic material, such as heavy metals, from the water column.
Salt marshes are very productive ecosystems and provide many ecosystem services including carbon cycling, nitrogen cycling, and coastal flood protection.
Coastal infrastructure is vulnerable to flooding from sea level rise, storms, and land subsidence. Salt marshes help to mitigate effects of flooding by directly buffering coastlines and dissipating waves. They are some of the many types of natural coastal landforms that are widely recognized as barriers to waves and tidal flows. Marsh vegetation causes wave attenuation and may account for up to 60 percent of wave reduction. Marsh plants also improve soil stability, which decreases soil erosion.
Salt marshes and other coastal wetland ecosystems play an important role in the global biogeochemical cycle, especially in the carbon and nitrogen cycles.
Coastal wetlands, such as salt marshes, can sequester carbon at a rate up to ten times that of a mature tropical forest. Through photosynthesis, marsh vegetation capture large amounts of carbon dioxide from the atmosphere. This carbon is stored in plant tissues and soil for hundreds or thousands of years. Coastal salt marshes can sequester about 210 grams of carbon per meter squared per year, which is 2-5 times more carbon per equivalent area than tropical forests.
Eh potential, the energetic favorability of a reaction, is the lowest in low marsh. Eh potential indicates the potential for carbon loss via oxidation into the atmosphere as carbon dioxide. Therefore, the low marsh may have the lowest carbon dioxide emissions compared to other parts of the marsh platform.
Both nitrification and denitrification occur in salt marshes. In nitrification, ammonium is oxidized to nitrite, then nitrite is oxidized to nitrate. In denitrification, organic matter is oxidized using nitrate as a terminal electron acceptor. Denitrification is highest in the low marsh. Nitrogen recycling is the lowest in the low marsh.