Australian Institute of Marine Science researcher Ray Berkelmans said Cyclone Fritz had granted the reef a reprieve from bleaching, which occurs when rising water temperatures stress corals and eventually kill them.

Berkelmans said the reef, one of Australia's biggest tourist attractions, was "frightfully close" to experiencing mass bleaching until the cyclone brought a cool change last month.

"We hope now we can cross our fingers and say ... we've missed it maybe by the skin of our teeth," he said.

The last serious bleaching occurred on the reef, considered one of the wonders of the natural world, in the summer of 2001/02, when five percent of corals were affected.

Berkelmans said continued global warming meant serious coral bleaching events would recur.

A report last month warned most of the reef's coral would be dead by 2050 because global warming was lifting sea temperatures.

TERRA.WIRE