Estuaries are home to large populations of marine life. The sheltered tidal waters of estuaries provide a safe environment for shellfish, crustaceans, fish and birds. The following organisms can commonly be found living or feeding in estuaries: mussels, clams, snails, shrimp, crabs, salmon, herring and trout. Widgeon, pintail, osprey and sandpiper seabirds also frequent estuary environments to feed on small crustaceans and fish.
The estuary biome is considered the nursery of the sea. Its partially enclosed nature provides a sheltered habitat for juvenile fish. Salmon, trout and herring lay their eggs in estuaries. Upon hatching, young fish use the safety of the environment to feed and gradually become accustomed to salt water. The abundance of plant life in these coastal zones helps young fish hide from larger predators.
Estuaries perform services that aid human welfare along the coast. In addition to providing erosion control, estuaries offer storm surge protection to coastal communities. Estuary vegetation helps anchor soil and sediment along shorelines and on river banks. Specifically, mangrove trees growing in shallow estuary waters have been known to buffer against cyclones, hurricanes and tsunami waves. These trees, along with other vegetation, act as natural barriers and help dissipate the energy of large waves that would otherwise crash on shore.
Estuaries help control pollution levels. Abundant plant growth in these coastal regions allows for the absorption of carbon dioxide through the process of photosynthesis. Estuary vegetation also filters pollutants out of water that may have been contaminated in upland areas. When estuaries are developed, filled in and built on, large amounts of carbon dioxide are released into the atmosphere due to vegetation removal.
