Yet another thing to watch out for in our reef tanks.
DISCOVER Vol. 25 No. 01 | January 2004 | Environment
70
Coral Killer Hitches a Ride in a Fireworm
For 20 years now, coral around the world has been turning ghostly white and dying, a condition known as bleaching. The coral loses the algae that live symbiotically inside and, consequently, its ability to photosynthesize. Scientists know that an obscure bacterium, Vibrio shiloi, is one cause. What they didn’t know—until now—is how the bacterium spreads.
V. shiloi is particularly active in Mediterranean waters—but only in summer when the water is warm. This year a team of microbiologists at Tel Aviv University discovered where the bacterium winters, which in turn led to an understanding of how it moves around. The culprit: a fireworm, a foot-long bristle worm that feeds on corals. “When we looked for the bacteria in the fireworm, we hit the jackpot,” says microbiologist Eugene Rosenberg.
The insides of a fireworm turn out to be a reasonably pleasant place for V. shiloi to camp out until external conditions turn favorable. The team introduced the germ-carrying worms into aquariums containing living corals. The pathogen caused total bleaching in just 17 days.
“It is likely that the fireworm picks up the bacterium in the summer by feeding on the coral and delivers it the next spring, when it again begins to feed on the coral,” Rosenberg says. The next step: figuring out how to control the wide-ranging fireworm.
—Michael W. Robbins
DISCOVER Vol. 25 No. 01 | January 2004 | Environment
70
Coral Killer Hitches a Ride in a Fireworm
For 20 years now, coral around the world has been turning ghostly white and dying, a condition known as bleaching. The coral loses the algae that live symbiotically inside and, consequently, its ability to photosynthesize. Scientists know that an obscure bacterium, Vibrio shiloi, is one cause. What they didn’t know—until now—is how the bacterium spreads.
V. shiloi is particularly active in Mediterranean waters—but only in summer when the water is warm. This year a team of microbiologists at Tel Aviv University discovered where the bacterium winters, which in turn led to an understanding of how it moves around. The culprit: a fireworm, a foot-long bristle worm that feeds on corals. “When we looked for the bacteria in the fireworm, we hit the jackpot,” says microbiologist Eugene Rosenberg.
The insides of a fireworm turn out to be a reasonably pleasant place for V. shiloi to camp out until external conditions turn favorable. The team introduced the germ-carrying worms into aquariums containing living corals. The pathogen caused total bleaching in just 17 days.
“It is likely that the fireworm picks up the bacterium in the summer by feeding on the coral and delivers it the next spring, when it again begins to feed on the coral,” Rosenberg says. The next step: figuring out how to control the wide-ranging fireworm.
—Michael W. Robbins
