Estuaries

Estuaries are those areas where fresh water from rivers and streams meets salt water from the ocean. These areas are extremely important, as they are some of the most biologically productive systems in the world. Estuaries serve several vital functions including providing food, nesting, and nursery ground habitat for aquatic animals as well as a variety of birds, mammals, and reptiles. Furthermore, these salt marsh systems offer filter, buffer, and "sponge-like" capabilities unlike any other ecosystem on earth.

Georgia's coastline, though only about 100 miles in length, is unique as its marshes account for nearly one third of the total salt marsh on the east coast of the United States. Sapelo Island, Georgia's fourth largest barrier island, is located midway on the Georgia coastline and is separated from the mainland by 5 miles of marsh and tidal waterways. A total of 16,500 acres make up Sapelo Island, of which, nearly 5,600 acres are tidal salt marsh. The Sapelo Island National Estuarine Research Reserve occupies just over one-third of Sapelo and is comprised of 2,100 upland acres and 4,000 acres of tidal salt marsh. The Reserve lies in the midst of an estuary where the currents of Doboy Sound and the Duplin River converge. The Reserve encompasses ecologies typical of the Carolinian biogeographic region which spans the south Atlantic coastline of the United States from North Carolina to Northern Florida. This region is characterized by vast expanses of tidal salt marshes protected by a buffer of barrier islands.

Here in coastal Georgia, nearly 90% of the marsh is covered by one species of plant, smooth cordgrass, known as "Spartina alterniflora." To survive in estuarine areas, marsh plants are uniquely designed to tolerate the salt water that floods the marshes twice daily at high tide. Likewise, aquatic animals that frequent the marshes are accustomed to fluctuating salinity and oxygen levels, temperature, and food availability.