Common bacteria kills elkhorn coral off Florida keys, says UGA res...( ral in the Caribbean has now been recom...)

The disease was first documented in 1996 on Eastern Dry Rocks Reef off Key West, Fla. in the Florida Keys National Marine Sanctuary and exclusively affects the elkhorn coral. Coral colonies affected by white pox disease show irregularly shaped white lesions which eventually kill the coral by consuming the thin layer of living tissue that covers a coral's limestone skeleton. This study has shown lesions growing as fast as 10.5 cm2 per day with an average rate of tissue loss of 2.5 cm2 per day, making it one of the most destructive coral diseases known. Tissue loss was greatest during periods of seasonally elevated temperature.

"Identification of this common bacterium as the cause of white pox means we cannot blame global warming as the main problem on coral reefs, but it all adds up," said Kathryn Patterson, a UGA Marine Sciences doctoral student and principal investigator who conducted her research under a cooperative training agreement while at the EPA's Gulf Ecology Division in Gulf Breeze, Fla. "Warmer water depresses coral growth but increases bacterial growth. In combination, this domino effect could foretell a disaster. There appear to be environmental changes occurring that may be making this non-pathogenic bacterium pathogenic."

According to Porter and Patterson, this disease has already killed more than 98 percent of the elkhorn coral on some reefs near Key West. The disease effects, compounded with additional stressors such as recent hurricanes, coral bleaching and ship groundings, have caused elkhorn coral populations to crash.

"When we started this research, we assumed that we were dealing with an undescribed marine pathogen. We had no idea that the culprit would turn out to be one of the most common bacteria known to man," said Porter. White pox affected coral has been found all over the Caribbean including Florida, the Bahamas,
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Contact: Kim Carlyle
kosborne@arches.uga.edu
706-583-0913
University of Georgia
17-Jun-2002