Floods threaten Australia's Great Barrier Reef

SYDNEY (Reuters) - Australia’s devastating floods are flushing toxic, pesticide-laden sediment into the Great Barrier Reef, and could threaten fragile corals and marine life in the world’s largest living organism, environmentalists said on Monday.

Flood plumes from the swollen Fitzroy and Burnett rivers in Queensland state had muddied reef waters as far as the Keppel Island Group, about 40 km (24 miles) offshore, at the southern end of the World Heritage-listed reef.

“Toxic pollution from flooded farms and towns along the Queensland coast will have a disastrous impact on the Great Barrier Reefs corals and will likely have a significant impact on dugongs, turtles and other marine life,” the World Wild Life Fund (WWF) said in a statement.

The Great Barrier Reef Marine Park Authority, which manages the 345,000 square km (133,000 sq mile) reef off Australia’s east coast, said sediment, fresh water, nutrients and high temperatures would damage or stress corals.

Marine experts expected to see coral bleaching as a result of the flooding now sweeping across central and southern Queensland.

“It’s fair to say the floods are not good news for the coral reef,” said park authority General Manager Andrew Skeats.

Bleaching occurs when the tiny plant-like coral organisms die, often because of high temperature and poisoning, leaving behind only a white limestone reef skeleton.

The worst floods Australia has experienced in 50 years, affecting an area the size of France and Germany combined, began last month and have severely cut Queensland’s $20 billion coking coal export industry, starving Asian steel mills of coal and pushing up world prices.

The damage to the Great Barrier Reef would be exacerbated because the floods are “bigger, dirtier and more dangerous due to excessive tree clearing, overgrazing and soil compaction”, the WWF said.

Experts expect the reef to recover, but depending on the coral resilience, that could take up to 100 years.

Skeats said the worst affected area at the moment was a relatively small part of the Great Barrier Reef and the Southern Barrier Reef, and the impact on the rest of the reef could be contained to a small area, if the weather was favourable.

A few species would also thrive in the conditions, with prized Barramundi fish and prawns relying on the fresh water flood runoff, and large areas of reef popular with tourists still largely unaffected, he said.

The Great Barrier Reef contributes A$5.4 billion ($5.4 billion) to the Australian economy each year from fishing, recreational use and tourism.

Reporting by Amy Pyett; Editing by Rob Taylor