Intertidal mud flats are located along the edges of the salt marsh. This harsh habitat is covered by water at flood (high) tide and exposed to the scorching sun at ebb (low) tide. It consists of a soggy substrate (soil) made up of clay and silt that is deposited during slack tide. Slack tide is the brief period between flood tide and ebb tide during which the water is not flowing in or out but is still. Only the upper layers of this muddy substrate contain oxygen. The deeper layers contain decaying organic matter that gives off a hydrogen sulfide gas that causes a rotten egg smell.
Georgia’s coastal marshlands encompass approximately 378,000 acres in a four to six mile band behind the barrier islands. Thriving in the waters of the estuaries, these marshes have been identified as one of the most extensive and productive marshland systems in the United States. There are nearly 400,000 acres of coastal marshlands in Georgia which represent a considerable portion of all remaining marshlands along the entire eastern coast of the United States.