Caribbean Coral Suffers Record Bleaching, Death

Bleaching from record hot water followed by disease has killed ancient and delicate coral in the biggest loss of reefs scientists have ever seen in Caribbean waters.

Researchers from around the globe are scrambling to figure out the extent of the loss. Early conservative estimates from Puerto Rico and the U.S. Virgin Islands find that about one-third of the coral in official monitoring sites has recently died.

Coral reefs are the basis for a multibillion-dollar tourism and commercial fishing economy in the Caribbean. Key fish species use coral as habitat and feeding grounds. Reefs limit the damage from hurricanes and tsunamis. More recently they are being touted as possible sources for new medicines.

The Caribbean is actually better off than areas of the Indian and Pacific ocean where mortality rates –mostly from warming waters- have been in the 90 percent range in past years. And with global warming, scientists are pessimistic about the future of coral reefs.

The heat causes the symbiotic algae that provides food for the coral to die and turn white. That puts the coral in critical condition. If coral remains bleached for more than a week, the chance of death soars, according to NOAA scientists.

In the past, only some coral species would bleach during hot water spells and the problem would occur only at certain depths. But in 2005, bleaching struck far more of the region at all depths and in most species.