CHARLESTON, S.C., Dec. 7 (UPI) -- U.S. scientists say they have discovered what causes some harmless marine bacteria to transform into killers that cause coral bleaching.
Dan Bearden and colleagues at the Hollings Marine Laboratory in South Carolina said bleaching already has destroyed up to 30 percent of the world's coral reefs, and scientists are searching for ways to slow or stop the damage.
They said one culprit is an ocean-dwelling bacterium, Vibrio coralliilyticus, that destroys corals' energy supply and kills the shell-clad marine animals. At lower temperatures, the bacteria are harmless to coral. But at temperatures above 75 degrees Fahrenheit the bacteria become virulent and can kill coral.
The researchers said their new study identified three chemicals -- betaine, glutamate and succinate -- that V. coralliilyticus produces in warmer water and are involved in the transformation.
Bearden and his colleagues say their findings open the door to understanding the biology involved in the complex interactions between corals and bacteria and unraveling the mystery of coral bleaching.
The research is reported in the journal Environmental Science & Technology.
