What Is Salt Marsh?
Salt marsh is an ecosystem that occurs between land and saltwater, an ecosystem that helps protect the coast. Salt marshes are populated by salt-tolerant plants like herbs, grasses and shrubs. These plants allow the salt marsh to trap sediment. The salt marsh then exports these nutrients to the coast. Salt marsh also creates a habitat for land-bound animals like mammals and migratory birds.
Where Do We Find Salt Marsh?
Salt marsh occurs on temperate coasts in sheltered environments like estuaries and embankments. In tropical areas, salt marsh is replaced by mangroves, marshes populated by salt-tolerant trees instead of salt-tolerant herbs. Salt marsh frequently occurs along the deltas of large rivers, like the Mississippi.
Salt Marsh is Unique
Unlike land-bound habitats, coastal salt marsh ecosystems are flooded by tidal flow every day. This tidal flow helps deliver sediments to salt marsh. The nutrients that collect in salt marshes make them highly productive environments that enable a broad food chain of organisms. In salt marshes we can find everything from bacteria to mammals. However, to survive, salt marsh organisms must be tolerant of salinity and flooding. Flora further inland are less exposed to salinity and flooding, and therefore don’t usually need to be as hardy, allowing inland salt marsh flora more diversity.
How Humans Have Harmed Salt Marsh
People flock to salt marshes for their beauty and coastal location. In 2002, over half of the world’s population lived within thirty-five miles of the coast. However, our population density along coasts means that we greatly impact salt marshes, often in negative ways. In the past people perceived marshlands as near-wasteland, and we used “land reclamation” to convert these areas into upland for agricultural purposes. After that, this upland was sometimes again converted into urban or industrial land, as in the cities of Boston and Tokyo. We have polluted salt marsh with runoff and nitrogen loading, introducing new species while killing off old ones. However, by altering marshlands, we have altered the salt marsh ecosystem. We’ve devastated salt marshes’ biodiversity and natural water flow.
Salt Marsh Perception and Restoration
Nowadays people are trying to restore salt marsh and reverse land reclamation. People no longer perceive salt marshes as “coastal wastelands,” and now see how biologically productive these areas are. In terms of biodiversity, people now perceive salt marshes as similar to tropical rainforests. Legislation such as the United States’ Clean Water Act now protects salt marsh habitats.