As a diver, I have explored and written about coral reefs for the past 16 years. Now I am learning to appreciate how the health of the Florida Keys reef system is entwined with other nearby habitats in the Caribbean and Gulf of Mexico. In 1997 federal researchers found that disease on Florida's coral reefs had increased nearly threefold. The disease may be linked to polluted runoff from draining the Everglades and the densely populated areas of South Florida. That understanding led to a gathering in October, 1998 of federal officials from agencies with activities that likely affect the reefs. "I've never seen so many heads of agencies sitting in one room focused on one issue." Scientist Gene Shinn of the US Geological Survey told The Miami Herald.
We watch a pair of damselfish, 4-inch long herbivores that create algae farms, scrape a patch of coral. Over time the fish feed on algae that grow on the damaged coral and large numbers of these fish can destroy the coral reef. Damselfish populations were previously held in check by groupers and snappers. Habitat destruction and overfishing have allowed a population explosion of damselfish.
The biodiversity of Florida's reefs and neighboring habitats is astonishing. The list conservatively includes 500 species of fish, 5 species of sea turtles, 62 species of hard coral, 1,320 species of mollusks, and between 500-700 species of sponges. And new species are still being discovered in Florida waters.
In order to understand the problems facing the reefs, one must understand the nature of the reefs themselves. Everyone in the Keys is concerned about this subject-from dive shop operators to tourists-and are learning basic coral biology in order to comprehend what they can do to save this resource.
Reefs thrive on the shallow edge of tropical seas where warm water currents brush the coast. Reef-building coral is made up of colonies of polyps. Each polyp absorbs calcium from the water and secretes a hard limestone skeleton. At night the polyps extend sticky tentacles from their skeletons to capture and consume small floating animals called zooplankton. Low on the reef's food chain are algae, plantlike organisms that convert sunlight to food. Some live on or in coral skeletons, making up about half the weight of each polyp and are responsible for coral colors.
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