Great Barrier Reef at risk of hot-spot bleaching within months

Peter Michael, couriermail 19 Dec 09;

SCIENTISTS warn the Great Barrier Reef faces a "double whammy" threat of coral bleaching this summer after record high temperatures.

Latest satellite imagery from the US shows a dire outlook for the Reef.

The National Oceanic and Atmospheric Administration, the peak US body, has forecast severe bleaching of the Reef within the next four months.

The entire Great Barrier Reef, worth $6.5 billion a year to the national economy, is painted red with potential "hot-spots" from south of Mackay to north of Cairns.

But Great Barrier Reef Marine Park Authority experts say their own outlook, based on local data, is not so alarming.

This comes with the United Nation's Copenhagen climate talks, described as a "defining moment for the planet", on the brink of spectacular failure.

The summit attended by 140 world leaders by last night had done little to clinch a legally binding deal to cut global emissions.

The Great Barrier Reef is universally cited as the world's first eco-system most likely to die off under human-induced climate change, possibly within decades.

But GBRMPA climate change director Dr Paul Marshall yesterday said local modelling suggested the latest four-month outlook might not be "as high" or as bleak as the NOAA forecast.

"Early indicators do not point to a super-hot summer," Dr Marshall said, based on Bureau of Meteorology and CSIRO figures. "But if we do have a hot summer on the back of the winter we've had we are in serious trouble."

The "double whammy" of Australia's hottest recorded six months on land and the warmest winter water temperatures on record was worrying.

"Usually over winter is when coral recuperate, get their health back, grow and build energy stores," he said.

"If we get above-average temperatures the corals go into summer already stressed, vulnerable and susceptible."

Great Barrier Reef coral bleaching risk low
Daniel Bateman, The Cairns Post 23 Dec 09;

THE Great Barrier Reef is at a low risk of coral bleaching this summer.

However, Reef managers warn this forecast may change in a matter of weeks.

The Great Barrier Reef Marine Park Authority has released its annual coral bleaching forecast for the reef, with the risk of widespread bleaching rated as low, on the basis of seasonal temperature trends.

Last year, the authority predicted a higher risk of coral bleaching, caused by rising summer sea temperatures.

The worst years so far for coral bleaching have been 1998 and 2002 – the two hottest summers on record.

GBRMPA chairman Dr Russell Reichelt said: "For the whole Reef, we’re saying that it’s low risk of bleaching, but there are indicators of higher risk of bleaching in the southern part of the reef. We’ve also got to take into account some of the long-range stuff.

"The weather bureau is telling us 2009-2010 is likely to be an El Nino year.

"That is one of the things in the past, where we’ve had our worst bleaching during an El Nino year, so we’re watching closely this El Nino pattern developing."

Dr Reichelt said any cyclonic activity or intense flooding over the summer could also result in coral bleaching.

Coral bleaching occurs when sea temperature rises more than one degree above coral’s normal range, forcing it to expel its symbiotic algae, which supplies coral with nutrients.