Coral bleaching sparks concern

2006-01-31 12:48

Sydney - Scientists warned on Friday that high ocean temperatures linked to global warming had caused severe coral bleaching in parts of Australia's Great Barrier Reef.

Researchers from the University of Queensland in eastern Australia found the bleaching in inshore reefs surrounding the Keppel Islands and said they were worried the phenomenon could spread across the Great Barrier Reef system.

They blamed the bleaching, caused when the plant-like organisms which make up coral die and leave behind the white limestone skeleton of the reef, on higher-than-normal temperatures during the southern summer.

"Corals at the Keppels are completely bleached and we are only halfway through January," said the University of Queensland's Ove Hoegh-Guldeberg.

"How this will develop across the Great Barrier Reef is the number one question right now," said Hoegh-Guldberg, who chairs a Bleaching Working Group for CRTR, an international coral reef research body linking more than 100 scientists worldwide and funded in part by the World Bank.

Some reefs badly damaged

The CRTR said water temperatures over the past four months have been well above long-term averages and United States oceanographers studying satellite imagery in January warned that bleaching was imminent on the southern end of the Great Barrier Reef.

"The traces suggest we are tracking the temperature profile of 2001 to 2002, which led to the worst incidence of coral bleaching in the recorded measurements for the Great Barrier Reef," Hoegh-Guldeberg said.

"In that event, over 60% of the Great Barrier Reef bleached and up to 5% of reefs suffered serious damage," he said.

The bleaching on the Great Barrier Reef followed the worst incidence of coral bleaching ever in the Caribbean in October 2005, the university said.

Climate change a concern

Coral reefs have recently been experiencing a global decline that scientists attribute to a combination of declining water quality, destructive fishing and global warming.

"Climate change is perhaps the most worrying aspect of these problems," Hoegh-Guldeberg said.

"Projections from over 40 climate models suggest that our oceans will warm by as much as three to four degrees Celsius in the next 100 years.

"This will have a huge impact on the health of these important ecosystems," he said.

The Great Barrier Reef is the world's biggest coral system, stretching over more than 345 000 square kilometres off Queensland's coast.

- AFP