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Columns::August 26, 2002
Herty--Unplugged
Law school appoints three professors to endowed positions
Clinical and administrative pharmacy faculty member is named first Jowdy Professor
Former Boston College dean appointed to Parham Chair
Inside scoop: New ad campaign reminds forest park visitors to respect others
Twenty new Foundation Fellows, seven Ramsey Scholars enter UGA
Professor takes issue with media’s portrayal of race, class and gender
A tale of two centers
Kudos
Update: Private Giving
Coming and Going
Campus News
Reef grief: Common bacteria kills elkhorn coral off Florida Keys
By Kim Carlyle
kosborne@uga.edu
Populations of the shallow-water Caribbean elkhorn coral, Acropora palmata, are being decimated by white pox disease. Losses
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| White pox disease infected this elkhorn coral growing in Eastern Dry Rock Reef off Key West. The irregularly shaped white lesions, caused by the common coliform bacteria Serratia marcescens, will eventually kill the coral. |
of living elkhorn coral in the Florida Keys typically average 85 percent.
A team of scientific investigators, led by James Porter, professor of ecology and marine sciences at UGA, has identified the common fecal enteric bacteria, Serratia marcescens, as the cause of white pox.
The source of the bacteria that is killing the coral is still under investigation, but it can be found in the intestines of humans and other animals. It can also survive as a free-living microbe in both water and soil. This is the first time this common bacterium has been shown to cause the death of marine invertebrates.
The research was published in June in the Proceedings of the National Academy of Sciences as an outcome of the Coral Reef Monitoring Project being conducted in the Florida Keys National Marine Sanctuary.
The project is supported by the National Oceanic and Atmospheric Administration and the U.S. Environmental Protection Agency.
The Coral Reef Monitoring Project began in 1995 as a component of the sanctuary’s water-quality protection program. The Florida Keys National Marine Sanctuary protects 2,896 square nautical miles of seagrass beds, mangroves, hardbottom areas and coral reefs, including elkhorn coral.
Elkhorn coral is an important Caribbean shallow-water species, providing both food and shelter for many animals on the reef.
Its massive branching form produces the highly complex three-dimensional structure upon which many other reef organisms depend. The structure itself frequently supplies the foundation upon which other species in the reef live.
“It is very sad that the one coral species affected is the magnificent branching elkhorn coral. These are the giant redwoods of the reef,” says Porter. “What used to be the most common coral in the Caribbean has now been recommended for inclusion on the endangered species list.”
The disease was first documented in 1996 on Eastern Dry Rocks Reef off Key West in the Florida Keys National Marine Sanctuary. It exclusively affects elkhorn coral.
Coral colonies affected by white pox disease show irregularly shaped white lesions that eventually kill the coral by
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| James Porter |
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 square centimeters per day, with an average rate of tissue loss of 2.5 square centimeters 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,” says Kathryn Patterson, a UGA marine sciences doctoral student and principal investigator, who conducted her research under a cooperative training agreement with the EPA. “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.
“These results suggest that we may be killing the goose that lays the golden egg,” says Porter. “Despite the trends in our data, we still remain hopeful that the surviving coral will repopulate the reef. We must maintain the highest possible water-quality standards in the Florida Keys. These coral reefs are so beautiful and so important. We must do our best to protect them.” |
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