Salt water marshes protect shores from wave and storm erosion by absorbing the energy of incoming waves and trapping and holding soil that might wash out to sea. Trapping soil builds up barriers protecting inland areas from floods. Salt marsh plants create shade keeping mud cool in the heat of day, then release the heat at night, regulating temperatures for wildlife as well as providing cover from predators. Many birds and insects depend on the salt marshes for nesting sites, some building hammock nests between blades. Seeds from salt marsh plants feed waterfowl and their decaying leaves wash into the water to become detritus (decayed organic material) for filter feeders and eventually fin fish.
Salt marshes release oxygen into the atmosphere during photosynthesis. The carbon they take out of the air for photosynthesis is often buried under soil washed from the land and sequestered, reducing greenhouse gasses.
Their ability to survive salt spray makes them a valuable resource for researches looking for ways to breed more vigorous plants for agriculture and bioremediation. As mineral salts build up in arid regions under agricultural irrigation, this ability to withstand salt conditions could mean survival for people dependent on California and Florida for food.
People cut salt marshes for livestock hay. A stand of cordgrass stores more energy as plant material than a comparable stand of most agricultural crops. (Closa & Wagner, 1998;Environmental Protection Agency b., 2001) People also use the grasses and seeds for art, baskets, and textiles, copy the motion of salt mashes in the wind for art. Salt marshes are frequently sought for their relaxing scenic value, bringing in tourism dollars to communities that protect them. The unique adaptations of species of these wetlands preserves a bank of DNA for future needs such as food crops to withstand climate change, biological waxes and plastics as petroleum supplies are depleted.