Fauna Journal Entry
Bleaching and Disease Kill Caribbean Reefs (April 29, 2006)
Much of the coral in the Caribbean Sea has died from bleaching and disease. NOAA.
Coral bleaching and disease are taking a huge toll on coral reefs in the Caribbean Sea. Recent surveys of reefs near Puerto Rico and the U.S. Virgin islands show that about one-third of the coral has died. Some of the colonies of coral had existed for over 800 years. The loss is devastating because the reefs grow by only the width of a dime each year.
Bleaching occurs when warmer water kills algae that living coral depend on for food. When the algae dies, the coral loses its color and turns white. Often, the coral dies as well.
The outer layer of a coral reef is made up of living polyps. These are tiny animals that lie on top of the skeletal remains of many earlier generations of coral.
In the Caribbean, sea temperatures rose dramatically over the past twenty years. The warming in 2005 was bigger than that of the previous twenty years combined. The bleaching that resulted struck coral at depths far from the surface and affected species not hit by warming before. The stress from bleaching made many species more at-risk of disease, which finished off many already weakened coral colonies.
The bleaching problem is just as bad in other parts of the world. In some areas of the Indian and Pacific oceans, about 90 percent of coral have been killed. Australia's Great Barrier Reef has suffered much damage. Some biologists fear that most of the world's remaining reefs will disappear in the coming decades if the situation doesn't change. The world's reefs are also threatened by sediments, farm runoff, pollution, and overfishing. In some parts of the world, reefs are blasted with explosives to gather tropical fish for pet stores.
Coral reefs are called "rain forests of the sea" because of their rich biodiversity. They provide habitat for about one-third of all the world's fish species and close to a million different kinds of animals overall.
