Florida Everglades

Florida Everglades Molly Hildebrand and Mark Gore

Geology • As glaciers in other areas of the world expanded, much of the earth's water supply was trapped in the ice. Sea levels in South Florida lowered as much as 300 feet below present levels. • At its peak, the sea level in South Florida rose 100 feet above present levels. The rocks beneath the everglades were formed in this sea. Calcium carbonate settling out of the water coated tiny bits of shell or sand in layer upon layer. The resulting spherical grains of limestone are called ooids. The Atlantic Coastal Ridge which runs from Mahogany Hammock northeast to Miami was formed as long shore currents pushed the ooids up into a long ridge. The ooids later cemented into rock known as Miami Oolite. Miami Oolite also covers most of the area east of Everglades National Park and most of Florida Bay.

In quieter waters covering the central portions of the everglades, tiny moss animals called Bryozoans flourished. As they died their calcium skeletons settled to the bottom. These sediment later cemented into rock known as Miami Bryozoan Limestone.

To create the Everglades, two other things besides limestone were required. These were water and a covering that was almost impassable in order to keep the water from escaping into the porous limestone. There was plenty of rain fall, about 60 inches (152 cm) per year that flowed from Lake Okeechobee to the sea. Another ingredient was needed, and that element was a soil called marl. The marl allows the water to seep into the limestone. As time marched on, this marl layer was covered by peat deposits which were created by decaying sawgrass and marsh plants.

History of the Everglades • Water in South Florida once flowed freely from the Kissimmee River to Lake Okeechobee and southward over low-lying lands to the estuaries of Biscayne Bay, the Ten Thousand Islands, and Florida Bay. This shallow, slow-moving sheet of water covered almost 11,000 square miles, creating a mosaic of ponds, sloughs, sawgrass marshes, hardwood hammock, and forested uplands. For thousands of years this intricate system evolved into a finely balanced ecosystem that formed the biological infrastructure for the southern half of the state.

Early colonial settlers and land developers viewed the Everglades as a worthless swamp in need of reclamation. The dream of draining the swampland took hold in the first half of the 1800s. By the 1880s developers started digging drainage canals, which took place without an understanding of the dynamics of the ecosystem and were generally inadequate for the task. • Today 50% of South Florida’s original wetland areas no longer exist. The numbers of wading birds, such as egrets, herons, and ibises, have been reduced by 90%. These grim indicators warn of a system under assault and in jeopardy of collapse.

Conservation of the Everglades • The harmful side effects of dredging and draining were apparent early in this century. • In 1928 landscape architect Ernest Coe began a concentrated effort to designate a "Tropical Everglades National Park." His persistence paid off when he and others persuaded Congress to designate the Everglades as a national park in 1934. It took park supporters another 13 years to acquire land and secure funding. In 1947 Everglades National Park officially opened, marking the first large-scale attempt to protect the "river of grass." Today, the park comprises a vast wetland wilderness unlike any other in the world.

Development throughout the last 50 years has led to many ecological problems in the everglades ecosystems. • While the park service now owns the majority of the land, conservation is still key. Stopping water pollution and protection of the endangered wildlife is necessary in order to allow for the next generation to enjoy the Everglades.

References http://nps.gov/ever//eco/index.html http://www.everglades.national-park.com www.dep.state.fl.us/secretary/post/2005/0722.htm

Florida Everglades