Coral reefs are among the most diverse ecosystems on the planet...and the most threatened. Artificial reefs may help stem the loss of these valuable and beautiful habitats, with shipwrecks, old subway cars, and other structures taking the place of living coral or rocky outcrops. The following Web sites introduce artificial reefs, reef ecology, and some ongoing efforts to establish reef communities...

From Wheeling Jesuit University and NASA-Classroom of the Future, this website introduces students to environmental challenges facing the world's coral reefs. This Coral Reefs learning module is part of the Exploring the Environment series (first reported on in the January 1, 1998 Scout Report for Science & Engineering) which present students with real-world environmental problems resulting from...