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  AIMS media release 1 Feb 06
Keeping an eye on the Keppels

ENN 1 Feb 06
Australia's Reefs Face Bleaching Risk
By Mike Corder, Associated Press

SYDNEY, Australia — A bout of coral bleaching hitting Australia's Great Barrier Reef could be as bad as an episode in 2001-2002 that affected 60 percent of the reef, scientists warned Tuesday.

An international team studying the world's reefs said in a statement that water temperatures for the past four months off Australia's northeastern coast have been well above long-term averages.

"We were all very concerned when we saw the temperature readings for December," said Prof. Ove Hoegh-Guldberg of the University of Queensland.

He said temperature measurements were similar to those in 2001-2002, which led to the worst coral bleaching ever recorded on the Great Barrier Reef. "In that event, over 60 percent of the Great Barrier Reef bleached and up to five percent of reefs suffered serious damage," he added.

Hoegh-Guldberg chairs the Bleaching Working Group for the Coral Reef Targeted Research and Capacity Building for Management Program, a worldwide network of more than 100 scientists.

Coral bleaching occurs when the microscopic plants, or zooxanthellae, which live in coral tissue stop working due to stress that often is caused by rising temperatures. The zooxanthellae provide corals with color and food. Coral reefs are not immediately killed by bleaching and if they are not severely stressed, they can recover their zooxanthellae and regain their color.

Bleaching already has whitened coral around the Keppel islands at the southern end of the Great Barrier Reef, a World Heritage-listed chain of reefs that stretches for almost 1,200 miles along most of the coast of Australia's Queensland state. "Corals at the Keppels are completely bleached and we are only halfway through January," Hoegh-Guldberg said. "How this will develop across the Great Barrier Reef is the number one question right now."

Healthy coral is key to marine ecosystems along the reef and also to a multibillion dollar tourist industry in Australia, where the Great Barrier Reef is one of the top draws.

Paul Marshall, manager of the Great Barrier Reef Marine Park Authority's Climate Change Response Program, said that while most of the tourism is based around the northern stretches of the reef, there are reefs of ecological importance and several popular resorts around the southern reaches.

Marshall said there had been reports late last year of some bleaching in the north of the reef, but temperatures there had since dropped while in the south temperatures continued to be above average.

"We are going to be pretty lucky to escape coral deaths in the southern Great Barrier Reef," he said. "It's going to have to be some pretty serious cloudy conditions to avert more serious bleaching down there," he added.

AIMS media release 1 Feb 06
Keeping an eye on the Keppels

The bleaching observed by marine researchers and tourist operators on reefs in the Capricorn region confirmed the AIMS/GBRMPA weather station data that show sea surface temperatures (SSTs) in this area are well above critical levels for normal coral function. SSTs in the Keppels have been hovering 2 degrees C above the average since early December, and this sustained warm period caused temperature-sensitive corals to reach bleaching thresholds as early as Christmas.

AIMS scientist and a world authority on coral bleaching, Dr Ray Berkelmans said "This is up to a month earlier than we?ve seen in previous bleaching events in 1998 and 2002. Since there is still a long way to go this summer, these conditions do not bode well for reefs in the Keppels".

But AIMS coral bleaching researchers remain optimistic, hoping for a repeat of the recovery witnessed on Keppel reefs following major bleaching episodes in 1998 and 2002. AIMS scientists were at the forefront in documenting the wrath of those dramatic summer heatwaves that bleached reefs worldwide.

Dr Berkelmans, said the Keppels suffered near 100% bleaching during those events but this area also recovered 3-6 months later, revealing a remarkable resilience not seen in many other places on the Great Barrier Reef. Research in the Keppel Islands is showing this area to be pretty special.

"We have found that corals have the ability to change the type of algae they associate with and that this alters their thermal tolerance. Corals in the Keppels also seem to grow faster than their northern counterparts and store more fats. We believe this may be at least part of the reason why the Keppels are able to bounce back from a heat wave that had dire consequences for other regions," Dr Berkelmans said.

AIMS Scientists are hopeful of a similar recovery following this bout of bleaching and will audit the situation in three weeks time as well as conduct more experiments. AIMS works closely with GBRMPA and the University of Queensland in monitoring and researching the effects of coral bleaching.
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