Coastal Marshes are a crucial ecosystem which influence, and are influenced by, many natural forces and human industries.
Coastal marshes are wetlands with fresh water, brackish water or salt water along tidal shores.
A transect of a 'typical' coastal marsh could include seawater, short salt marsh grasses, taller salt marsh grasses and other plants, brackish water plants on slight elevation, and, finally, taller brackish water plants on land above high tide. The biome includes plants which thrive on salty or brackish water, and the many animals which inhabit this rich environment. In much of the eastern United States, the dominant plant species for coastal salt marshes is Spartina alterniflora . The interconnected root system of these grasses anchors the soil in the face of tidal activity. If the spartina population is healthy, and conditions are right, the marsh may grow to fill in tidal ponds and creeks.