The only coral reefs in the continental United States are located off the southern tip of Florida, in the Florida Keys. These coral reefs are already under tremendous stress as a result of human activity from pollution, fertilizer run-off, and historical changes to the water circulation through the Everglades (read more...). These issues have already caused changes to the coral’s fragile ecosystem. The damages incurred include disease, damage from anchors and boat groundings, overgrowth of algae (caused by the input of nutrients), and “bleaching” that happens when the symbiotic zooxanthellae become stressed and die or otherwise abandon the coral colony. According to the Florida Department of Environmental Protection, there has been a 44% decline in coral cover from 1996 to 2005.[1] What’s more, coral grows at a very slow rate, “from one to sixteen feet every 1,000 years."[2] If the oil from the Deepwater Horizon spill reaches the coral reefs of Florida, the result could be devastating for this already overburdened ecosystem.

Spur and Groove Coral Formation

Spur and Groove Coral Reef Formation

The Florida Keys coral reef system extends from Key Largo to the Dry Tortugas. The system is not one long coral reef, but rather a series of reef formations on a ridge paralleling the coastline. Each of these reefs features spur and groove coral formations – alternating ridges of coral and rock separated by wide grooves of sand, arranged perpendicular to the coast. The waters surrounding these reefs are typically very clear as a result of the nearby Florida Current (part of the Gulf Stream).

All of the Florida Key reefs are popular with scuba divers. Some of the larger and most popular reefs are marked by lighthouses. Two of the most famous reefs within this system are Molasses Reef and Looe Key Reef. Molasses Reef is located off of Key Largo, on the far eastern end of the Florida Keys. Like many reefs in the Keys, Molasses Reef is named for an early shipwreck, this one carrying barrels of molasses. Looe Key Reef is located about seven nautical miles offshore of Big Pine Key, a little more than half-way down the Florida Keys island chain. Looe Key is named after the British warship H.M.S. Looe which sank in 1744 in that area. Looe Key isn’t actually a key (or cay, the Caribbean word for “island”), but the shallowest parts of the reef can be out of water during very low tides. All of the coral reefs in the Florida Keys are now protected as part of the Florida Keys National Marine Sanctuary.

Looe Key Seafan

Looe Key Seafans

[1] Threats to Southeast Florida Coral Reefs

[2] Florida's Coral Reefs