Where in the World

It's estimated that about 268,600 square miles of coral reefs exist in the world's oceans, but they vary widely in degrees of health. Here's a sampler of some major reefs and their vital signs:

• Australia's Great Barrier Reef:About 1,245 miles long. It is composed of 2,500 individual reefs, most of which are in good condition. The longest barrier reef in the world, it harbors about 400 species of coral.

• Red Sea Reefs:About 2,635 miles in combined length, these reefs are shared by Egypt, Sudan, Ethiopia, Saudi Arabia, and North Yemen. Sections suffer from the effects of industry and tourism, but North Yemen's reefs are nearly untouched.

• Florida Keys National Marine Sanctuary:About 230 miles long. Natural damage from storms and periodic cold temperatures, along with boat groundings, threaten some areas.

• Philippine Reefs:About 13,941 miles long. Thirty percent of the reefs are dead; 39 percent are only partly alive. They have been heavily damaged by dynamite and cyanide fishing. They are also stressed by tourism.

• Reefs of the Pacific Atolls:About 17,000 miles in combined length in the South Pacific. There are more pristine reefs in this area of the world than anywhere else. Polynesian reefs are becoming trashed.

• The Belize Barrier Reefs:At 294 miles long, they are the world's second longest barrier reef and are in remarkably good shape. Also renowned for pristine mangrove swamps that interact with reef ecosystem.

• Reefs of the Bahamian Archipelago:About 1,072 miles in combined length. There is some damage from tourist activities, but reefs are generally in excellent health.

Ocean Planet Exhibition Floorplan

gene carl feldman (gene@seawifs.gsfc.nasa.gov) (301) 286-9428
Judith Gradwohl, Smithsonian Institution (Curator/Ocean Planet)