Coral Bleaching and Coral Diseases

A relatively rapid warming of Earth's climate, from the greenhouse effect (the trapping of heat in the lower atmosphere by gases generated by the burning of fossil fuels and from deforestation) may be partly responsible for a problem called coral bleaching. Corals bleach, or turn white, when the algae—which give the corals their color—are expelled from the corals' tissues, revealing the underlying limestone skeletons through their transparent skin. Laboratory experiments have indicated that corals bleach in response to stress, such as from increased water temperatures. Some corals recover from bleaching, but others die. Scientist also believe that bleached corals may be more vulnerable to disease or storm damage.

These are not the only problems confronting coral reefs. Coral diseases appeared to be on the rise in 2000. The cause of many of these infections was a mystery.

Environmental change has influenced coral reefs since their evolution millions of years ago. Disturbance is, in fact, a natural and important part of life on a reef. Storms, for example, wash out debris, disperse live coral fragments, and provide space for growth. In this way, reefs can recover from such stressful natural events as storms.

However, scientists fear that the added stress from human activities may be too much for the reefs to bear. Therefore, researchers welcomed the plan announced by the Coral Reef Task Force and other efforts to protect reefs. Although the Earth's coral reefs are at risk from numerous interacting factors, scientists hoped these efforts would help prevent further damage to coral reefs and promote the recovery of these beautiful and valuable natural treasures.