Estuaries across the globe have similar characteristics. They lie between land and ocean, contain a mixture of salt water and fresh water, and accumulate large amounts of sediment and organic material. They also share the same threats from human activity. 

1. SAV—Submerged Aquatic Vegetation
   These plants are sources of food and habitat for many shellfish, finfish, birds, amphibians, reptiles, invertebrates, and mammals. SAV provide nurseries for young fish. The plants trap sediment by slowing water currents. This causes the suspended particles to drop to the bottom.
2. Wetlands
   The high primary productivity in the wetlands fuels food webs. Wetlands are a source of food and shelter for juvenile aquatic organisms and filter sediment, nutrients, and contaminates. They are carbon and nitrogen sinks. Wetlands are important habitats for birds, reptiles, mammals, and invertebrates and protect the land from eroding and flooding.
3. Filter Feeders
   These organisms filter suspended particles to obtain food by straining the water. Anything not eaten is bound with mucus and discarded. The heavier waste pellets fall to the bottom. If not consumed by decomposers, sediment covers the organic material, becoming a natural sink.
4. Pit Stops for Migratory Birds
   The North American migratory flyways describe the routes followed by migratory birds. Though the routes vary with each species, they often intersect at estuaries. Estuaries are important stopovers for the birds to rest and eat so they can refuel for their long journeys.
5. Habitats for Endangered Species
   Estuaries and their tributaries offer sheltered habitats for threatened species like sea turtles and manatees.
6. Natural, Economic, and Aesthetic Values
   The sheltered access to the sea offers people commercial and recreational fishing, boating, tourism, and other coastal industries. Estuaries provide spawning and nursery grounds for commercial fisheries.

Estuaries