Smithsonian Institution
National Museum of Natural History: Ocean Portal: Corals and Coral Reefs
Learn about corals and the importance of coral reefs to ocean ecosystems. Find out how reefs are created, what threats they face, and what kinds of conservation tactics are being used to protect and preserve them.
Center for Educational Technologies
Nasa Classroom of the Future: Coral Reefs: Dissappearing Resource
Why are the reefs disappearing? Use this site to explore the science behind the issue. Useful at several grade levels.