April 02, 2006

Biggest Caribbean coral die-off ever.

Record water temperatures and disease have caused the worst die-off of coral in the Caribbean Sea ever recorded. Scientists report that surveys at monitoring sites throughout the Caribbean show that up to one-third of the coral is dead — but this preliminary estimate may turn out to be conservative.

The immediate cause of the coral die-off is abnormally high water temperatures in the Caribbean. These elevated temperatures kill the algae symbiotes that provide food for the coral, turning them white in the process — a process called 'bleaching.' Coral that remains bleached for more than a week will probably die.

Before this year, bleaching occurred in the Caribbean only during short periods and only among certain species. But the current bleaching episode is taking place all over the sea and among a wide range of species. Much of the coral killed this year had already been weakened by bleaching from last year.

Dead coral in the Caribbean. [Photo: AP]

From an AP report on the die-off:

[According to National Park Service fisheries biologist Jeff Miller] "The mortality that we're seeing now is of the extremely slow-growing reef-building corals. These are corals that are the foundation of the reef ... We're talking colonies that were here when Columbus came by have died in the past three to four months...."

The Caribbean is actually better off than areas of the Indian and Pacific ocean where mortality rates — mostly from warming waters — have been in the 90 percent range in past years, said Tom Goreau of the Global Coral Reef Alliance. Goreau called what's happening worldwide "an underwater holocaust."

And with global warming, scientists are pessimistic about the future of coral reefs.

"The prognosis is not good," said biochemistry professor M. James Crabbe of the University of Luton near London. In early April, he will investigate coral reef mortality in Jamaica. "If you want to see a coral reef, go now, because they just won't survive in their current state...."

"The 2005 event is bigger than all the previous 20 years combined," he said.

What happened in the Caribbean would be the equivalent of every city in the United States recording a record high temperature at the same time, Eakin said. And it remained hot for weeks, even months, stressing the coral.

So do we have to lose all of the reefs in the Caribbean and other oceans before Dubya's administration takes global warming seriously?

Posted by Magpie at April 2, 2006 03:38 AM | Environment | Technorati links |