SAN JUAN, Puerto Rico (AP):
A BLEACHING phenomenon caused by unusually warm waters is whitening coral reefs throughout the Caribbean, raising fears of a large-scale die-off of the vital organisms, scientists said yesterday.
Global atmospheric temperatures have been slowly raising ocean temperatures, threatening sea coral that can only live within a narrow temperature margin, according to scientists. A slight increase in sea surface temperature can induce coral bleaching, killing the coral.
Recent data gathered by the University of Puerto Rico shows that up to 95 per cent of coral colonies off the island have been bleached in some areas.
MASSIVE DIE-OFF
"The concern is that we may be witnessing a massive die-off. Reports from Vieques (Puerto Rico), Barbados and many other Caribbean islands is grim," said Mary Ann Lucking, director of the Puerto-Rico-based conservation group Coralations.
WHEN BLEACHING OCCURS
The bleaching occurs when the microscopic plants, or zooxanthellae, which live in coral tissue stop working. The zooxanthellae provide corals with colour and food.
Without them, corals usually die. Since March, the northeast Caribbean has had higher than normal sea surface temperatures. The trade winds, which usually help cool the sea, were also not as strong as they have been in the past.
"When the trade winds blow, they usually blow across the surface of the water, and cause water from the bottom, cooler water, to rise up to the surface, which keep the Caribbean cooler. That didn't happen this year and we don't know why," said Lucking.
Prior to the 1980s, coral bleaching events were isolated and appeared to be the result of short-term events such as storms or pollution.
