Unusually Warm Caribbean Sets Off Bleaching of Coral

Unusually warm temperatures in the Caribbean have caused severe coral
bleaching in recent weeks that could permanently damage many reefs,
according to the National Oceanic and Atmospheric Administration.

NOAA, which monitors corals in 24 shallow coral reef systems across the
globe, has issued bleaching alerts in Puerto Rico and the U.S. Virgin
Islands. Since early September, water surface temperatures in parts of the
Caribbean have been averaging 2 degrees Fahrenheit above historic monthly

Warm sea surface temperatures subject corals to extreme stress, which
prompts them to expel the symbiotic microalgae that live in their tissues
and provide them with food.

Losing the algae deprives the coral of color and makes it appear b leached;
bleaching that lasts longer than a week can kill corals.

"Puerto Rico is experiencing the worst bleaching event ever," said Ernesto
Weil, a University of Puerto Rico professor. "Bleaching is both widespread
and intense, with colonies representing 42 species completely white in many
reefs. In our surveys, 85 to 95 percent of coral colonies were bleached in
some reef areas."

Manatee Press