Coral reefs are scattered throughout the tropical and subtropical western Atlantic and Indo-Pacific oceans. About 600,000 km2 (231,600 mi2) of coral reefs are known to exist, comprising 0.17% of the ocean's surface. The Great Barrier Reef off northeastern Australia in the Indo-Pacific is the largest barrier reef in the world, stretching more than 2,000 km (1,240 mi.).
Reefs are built by vast colonies of coral polyps - tiny invertebrate animals related to sea anemones and jellyfishes. Reef-building corals secrete calcium carbonate skeletons. The calcium carbonate gradually accumulates and the reef becomes large.
Coral reefs are one of the most biologically diverse ecosystems, rivaling rain forests for the number of species inhabiting them. About 6,000 to 8,000 fish species as well as sponges, sea anemones, bryozoans, worms, sea stars, crustaceans, and snails live on coral reefs.
In addition to the array of marine life they support, reefs also protect coastlines from erosion, provide food and recreation for people, and are proving to be a new frontier for medical research. Unfortunately, reefs are threatened worldwide by pollution, development, and coral harvesting. More than one-third of all coral reefs have already been destroyed or permanently damaged.
To strengthen efforts for coral reef management and conservation, the U.S. Departments of State and Commerce joined with nations around the globe and declared 1997 the International Year of the Reef. You can help protect reefs by not purchasing coral or other living souvenirs and by keeping the ocean clean. If you plan to visit a coral reef, learn how to safely enjoy this living system.
For more information about coral reefs, explore the Coral and Coral Reefs Infobook.
Additional Information Sources - Coral Reef Conservation
Center for Ecosystem Survival
Adopt A Reef
699 Mississippi Street
Suite 106
San Francisco, CA 94107
CITES Conservation Treaty Support Fund
3705 Cardiff Road
Chevy Chase, MD 20815
Reef Relief
P.O. Box 430
Key West, FL 33041
National Audubon Society
700 Broadway
New York, NY 10003
National Geographic Society
1145 17th Street, NW
Washington, DC 20068-4688
The Nature Conservancy
Rescue the Reef Program
1815 North Lynn Street
Arlington, VA 22209
Wildlife Conservation Society
18th Street and Southern Boulevard
Bronx, NY 10460
The Coral Reef Alliance
64 Shattuck Square
Suite 220
Berkeley, CA 94704
IUCN/World Conservation Union
1400 16th Street, NW
Washington, DC 20036
National Fish and Wildlife Foundation
1120 Connecticut Avenue, NW
Suite 900
Washington, DC 20036
National Wildlife Federation
Education Outreach Department
8925 Leesburg Pike
Vienna, VA 22184-0001
U.S. Department of Commerce/NOAA
14 & Constitution Avenue, NW
Room 6225
Washington, DC 20230
World Wildlife Fund
1250 24th Street, NW
Washington, DC 20037
