Sewage bacteria blamed for coral disease

June 18, 2002

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By Jeff Nesmith, Palm Beach Post Washington Bureau

Tuesday, June 18, 2002

WASHINGTON -- An epidemic of " white pox " that has decimated the

once-plentiful elkhorn coral in the Caribbean has been traced to bacteria

found in sewage, scientists are reporting today.

The epidemic has reduced populations of elkhorn by as much as 70 percent in

waters surrounding some Florida keys.

" It is very sad that the one coral species affected is the magnificent

branching elkhorn coral, " University of Georgia ecologist Porter said.

" These are the giant redwoods of the reef, " he said. " What used to be the

most common coral in the Caribbean has now been recommended for inclusion on

the endangered species list. "

Porter and a team of scientists from universities, government and private

industry are reporting in the Proceedings of the National Academy of

Sciences that they have established that the epidemic is caused by bacteria

called Serratia marcescens.

The organism is found in the digestive tracts of humans and many other

animals, Porter said.

To identify the reason for the disease, which causes pale blotches to grow

on the normally tan coral, researchers collected material from the outer

edges of each and grew the bacteria found there in a laboratory

seawater-based " broth. "

Genetic analysis confirmed that Serratia marcescens was the microbe culprit,

they said.

Porter said the white pox disease is extremely contagious among cora.

White pox often is confused with coral bleaching, a different cause of coral

death.

Yet the two may be related, said , a researcher who works

with Porter.

" Identification of a fecal enteric bacterium as the cause of white pox means

we cannot blame global warming as the main problem on the coral reefs, but

it all adds up, " she said. " Warmer water depresses coral growth, but

increases bacterial growth. In combination this domino effect could foretell

a disaster. "

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