Warm temps hit Caribbean coral reefs

WASHINGTON, Oct. 12 (UPI) -- An unexplained sea temperature rise has caused a major coral bleaching and die-off event in the western Caribbean, U.S. researchers say.

Scientists from the Smithsonian Tropical Research Institute and divers first found coral bleaching in July in waters off Panama followed by an extensive bleaching event in September, an institute release said Tuesday.

During this time, seawater temperatures were measured at 89.6 degrees Fahrenheit, well above the seasonal average of about 82 degrees.

The warming event is affecting the entire Caribbean coast of Panama and has also been reported at sites in Costa Rica, Smithsonian scientists said.

Coral reefs contain photosynthetic algae called zoxanthellae, and bleaching occurs when corals lose their color as a result of the loss of their algal component caused by increased water temperature or other stress factors.

Bleaching impairs vital functions of the coral such as reproduction and growth.

Smithsonian scientist Hector M. Guzman says the hurricane season may be part of the current problem by causing low water circulation in the southwestern Caribbean and thus creating a "warm pocket" of water along the coasts of Panama and Costa Rica.