Geography and Ecology of The Everglades - Florida Bay

Florida Bay

Because much of the coast and inner estuaries are built by mangroves—and there is no border between the coastal marshes and the bay—the ecosystems in Florida Bay are considered part of the Everglades. More than 800 square miles (2,100 km2) of Florida Bay is protected by Everglades National Park, representing the largest body of water in the park boundaries. There are approximately one hundred keys in Florida Bay, many of which are mangrove forests. Larger islands may be taken over by hardwood hammocks. The outer rims of the Ten Thousand Islands and Cape Sable share characteristics of the intertwining saltwater bays and fresh water marshes.

The fresh water entering Florida Bay from the Everglades creates ideal conditions for vast beds of turtle grass and algae formations that foster animal life in the bay. Sea turtles and manatees (Trichechus manatus latirostris) eat the grass, while invertebrates such as worms, clams, and other mollusks consume algae formations and microscopic plankton. Female sea turtles return annually to nest on the shore, and manatees spend the winter months in the warmer water of the bay. The Calusa Indians had various uses for shells of marine invertebrates, due to the lack of dense rock with which to make tools. They used the horse conch (Pleuroploca gigantea), left-handed whelk (Busycon contrarium), and the Florida crown conch (Melongena corona) as drinking vessels, picks, hammers, knives and awls.

Sea grasses stabilize sea beds and protect shorelines from erosion by absorbing energy from waves. Shrimp, spiny lobsters, and sea urchins live in and among the grasses and feed on phytoplankton; they in turn feed larger predators such as sharks, rays, barracuda, and king mackerel (Scomberomorus cavalla). Due to shallow water and abundant sunlight, Florida Bay hosts communities of coral reefs and sponges, although the majority of the state's reefs are closer to the Florida Keys. Everglades keys that foster mangroves also support nurseries for wading birds such as the Great white heron (Ardea herodias), which was almost wiped out in the Labor Day Hurricane of 1935 (only 146 were counted afterward). After recovering to number more than 2,000, they were further endangered by Hurricane Donna in 1960, which decreased their numbers by 35 to 40 percent.

Sea floor patterns of Florida Bay are formed by currents and winds. However, since 1932, sea levels have been rising at a rate of 1 foot (0.30 m) per 100 years. Though mangroves serve to build and stabilize the coastline, seas may be rising more rapidly than the trees are able to build.