Coastal lagoons are shallow bodies of brackish water. They are located parallel to the shoreline. Coastal lagoons are separated from the ocean by natural barriers, such as banks of sand. They are linked to the ocean via small breaks in the sandbanks. The water in coastal lagoons is a mix of seawater and fresh water, known as brackish water. These shallow bodies of water are influenced by tides and weather. Precipitation and evaporation, as well as the rise and fall of sea levels, effect the lagoon's concentration of salt or salinity. What's more, coastal lagoons are unique ecosystems. They are nurseries for marine organisms and sanctuaries for bird. Coastal lagoons are an important habitat for many species of crustaceans and fish.