saltmarsh

Saltmarsh is a coastal wetland found in sheltered, intertidal zones such as estuaries, lagoons, and deltas where tides bring seawater and freshwater together. Soils are saturated and saline, and the vegetation is dominated by halophytic plants such as cord grasses (Spartina spp.), glassworts (Salicornia spp.), and various rushes and grasses. In many systems a distinctive zonation develops, with lower marsh plants adapted to frequent inundation and higher marsh communities that tolerate drier, less saline conditions.

Saltmarshes form through the accumulation of sediment and plant material, building vertically in response to tidal flows and sediment supply. They are dynamic ecosystems shaped by tides, salinity, sedimentation rates, and sea level changes. Because they sit at the boundary between land and sea, they are particularly sensitive to rising sea levels and human alterations of sediment delivery.

Ecologically, saltmarshes provide critical habitat for a wide range of species and life stages. They serve as nursery and feeding grounds for fishes, crustaceans, and invertebrates and provide foraging habitat for many migratory and resident birds. They contribute to nutrient cycling, trap and store organic carbon (a component of blue carbon, important for climate regulation), and help stabilize coastlines by dampening wave energy and reducing erosion.

Global distribution is broad, occurring along temperate and some subtropical coastlines. Threats include land development, pollution, dredging, altered hydrology, and sea level rise. Some regions have experienced invasion by non-native Spartina species, which can disrupt native marsh communities. Conservation and restoration efforts include protection of existing marshes, marsh restoration, and managed realignment to restore natural tidal processes.