AN EPIDEMIC of coral bleaching hitting Australia鈥檚 Great Barrier Reef has sparked fears that much of the world largest coral reef may be dying. Bleaching is also reported to be spreading through the coral islands of the South Pacific.
Coral bleaching occurs when high sea temperatures force the algae that give coral its colour out of the coral polyps. Bleached coral may recover in the next cool season, but if all the algae are lost the coral will die and reefs will crumble.
An extensive survey of the Great Barrier Reef over the past month has revealed widespread bleaching, says Terry Done, chief conservation scientist at the Australian Institute of Marine Science in Townsville, Queensland. This is the second epidemic of coral bleaching in four years.
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Thomas Goreau, president of the Global Coral Reef Alliance in Chappaqua, New York, says he has received reports in the past few days of bleached, dead coral across much of the South Pacific, including Tahiti, the Cook Islands, New Caledonia and Fiji. 鈥淚t will take a long time before we have full confirmation of the magnitude of the disaster,鈥� he says. 鈥淏ut I predict we will have confirmation that almost all corals across the entire South Pacific have died in the last few months.鈥�
The bleaching follows this summer鈥檚 record sea temperatures off Australia. 鈥淎lmost all the Great Barrier Reef was 2 掳C or more above normal for more than two months from early January to mid-March,鈥� says Goreau. 鈥淭his was hotter and longer than the bleaching that wiped out the Maldives, Seychelles and western Australian reefs in 1998.鈥�
The high temperatures appear to be connected to the likely onset of a new El Ni帽o, like the one that caused the bleaching in 1998. But Goreau says global warming is a key underlying factor: 鈥淚t means reefs are already under stress before El Ni帽o starts.鈥�
The Great Barrier Reef Marine Park Authority confirmed for the first time this week that there had been 鈥渆xtensive coral bleaching along much of the length of the reef鈥�. Much of it was visible in aerial surveys and had 鈥渁ffected a range of reef organisms鈥�. The aerial surveys are being followed up by detailed monitoring by divers.
Done told 快猫短视频 that little of the coral has died yet. But Goreau remains pessimistic. He claims that the Australian government is unwilling to discuss the extent of bleaching on the reef because it is reluctant to take action on global warming.