The Marshes from Shell Mound

Gulf Coast Salt Marshes from Shell Mound 10/17/2010

This photo, made from Shell Mound on Levy County, Florida's Gulf Coast, shows low and high salt marshes. The low marsh, farthest from Shell Mound and closest to open water, is an irregular light-colored band of smooth cordgrass (Spartina alterniflora). Closer in is a wide expanse of the darker black needlerush (Juncus roemerianus). This pattern repeats in many coastal areas. Smooth cordgrass is more tolerant of flooding. It traps sediments and raises the level of the marsh, moving its edge toward open water. By raising the level of soil, it creates habitat suitable for the needlerush.

The shell mound is a several thousand year old Indian midden covering five acres and rising 28 feet above mean sea level. It and the surrounding marshes are protected by the Lower Suwannee National Wildlife Refuge.