This program looks at the ecosystem of coral reefs. It examines the natural disasters that threaten them, like severe storms, or the proliferation of a species like the starfish, which is ravaging the Australian Barrier Reef—perhaps a natural event, perhaps the result of an artificially-induced change in the environment that is destroying the starfish’s normal predator. In seeking the reasons why coral reefs are shrinking everywhere, the program looks at the effects of pollution: particles in suspension in the water that affect photosynthesis in marine plants or that settle and upset the surfaces inhabited by marine life; the result of deforestation and run-offs; the effects of sewage on algae, which compete for space with coral; and the effect of people, from fishermen who overfish to tourists who destroy beaches to oil companies whose tankers spring leaks and destroy everything in the water and on shore. (28 minutes)