Nancy Gladson Diersing

Nancy Gladson Diersing: member of the Research Staff at the Florida D.E.P. Florida Marine Research Institute in Marathon, FL. Her background includes ten years as a classroom and field educator. With a master's degree in zoology, she has been very active in Florida Bay studies, and in her four years with FMRI worked on the Florida Bay Project.

The Northern Transition Zones of Florida Bay are the recipient of rainwater which collects in the streams and lakes in the Kissimmee River Basin, which feeds into Lake Okeechobee. In the historical drainage pattern, freshwater which pooled in the lake spilled over its southern rim, forming a broad, slow-moving river known as the Florida Everglades. Only a foot deep in most places, this freshwater sawgrass prairie, dotted with elevated tree islands, bayheads, and bald cypress domes, was 70 miles wide and stretched over 100 miles from north to south. Everglades National Park which covers the southern tip of the peninsula encompasses much of what remains today of this once-vast Everglades wilderness and most of Florida Bay. In the southernmost portion of the peninsula, the open sawgrass community is replaced by the more salt-tolerant buttonwood, red, black, and white mangrove trees which grow in the shallow water along the shoreline. This Northern transition zone, characterized by this fringe mangrove forest and mangrove-lined creeks, experiences great fluctuations in salinities depending upon the quantity and timing of freshwater input. At times of high rainfall on the mainland, these highly-productive estuarine waters are actually quite low in salinity. Animals and plants inhabiting this zone are adapted to survive in the changing seasonal conditions found in the fringe mangrove community.