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Great Barrier Reef threatened by toxic flood debris - scientists

posted 1 Apr 2011, 09:24 by Mpelembe   [ updated 1 Apr 2011, 09:26 ]

Environmentalists in Australia are calling for a review of land management practices following Queensland's recent devastating floods which they say, have flushed toxic, pesticide-laden sediment into the Great Barrier Reef. They say there's evidence the reef has already suffered damage and fear it will get worse.

BOWEN BASIN, QUEENSLAND, AUSTRALIA, REUTERS - From the air, the trail of environmental devastation left by Queensland's record-breaking floods is clear to see. River banks have been eroded, farmland has

been destroyed and the state's all-important mining industry is still struggling to recover.

The torrential rains stopped two months ago, but the Fitzroy River is still swollen as it carries run-off to the Pacific Ocean. What concerns environmentalists and scientists now, is the tonnes of sediment and toxic sludge they say have been carried along with the flood water. They say flood plumes from the swollen rivers have muddied reef waters as far away as the Keppel Island Group, about 40 km (24 miles) offshore, at the southern end of the World Heritage-listed Great Barrier Reef.

Michelle Devlin, a scientist with James Cook University, who runs marine monitoring in and around the reef, says the plumes could spread hundreds of kilometres

north to the environmentally sensitive Whitsunday Passage. She says there's evidence that run-off has already caused damage to sensitive coral areas off the coast.

"What we've done is we have changed the quality of the water, so our activities on the catchment through increased agriculture and through urbanisation is that we've changed that quality of water - there's high nutrients in there, there's higher sediments, there's pesticides that could potentially impact on the reef," she said.

Devlin and other experts say they expect to see coral bleaching as a result of the flooding that swept across central and southern Queensland in December and January.

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 floods were the worst Australia has experienced in 50 years, affecting an area the size of France and Germany combined. At least seventy towns and 200,000 people were affected and three quarters of the state was declared a disaster zone. According to Michelle Devlin, the disaster is far from over.

"We need to really understand the impact of that amount of fresh water plus combined with the other pollutants that are in the water and as we have said we are starting to see some aspects of bleaching and potentially mortality in those inshore reefs." she said.

The flooded areas feeding into the Fitzroy and Bowen Basin river systems comprise large grazing and agriculture areas and Queensland's highest concentration of coal mines.

The Fitzroy region is 82% grazing land and many argue that farming practices are the major contributing factor to the sediments in the plumes.

Susie Christiansen, who is the Chief Executive Officer of the Fitzroy Management Authority agrees that water being flushed out of flooded mines is partly to blame, but the run-off from farm land is causing the bulk of the problem.

"Sediment comes off just the massive extent of both grazing and cropping lands and like I said 82 percent grazing. It's coming of hill slopes, its coming off gully erosion and its coming from stream banks and its not about pointing the finger, its just about the scale," she said.

Michelle Devlin also points to climate change as the cause of the extreme weather conditions that brought the floods. She says reducing greenhouse gases will make a difference in the long term, but the more immediate solution to future problems cause by flooding, is better land management. Susie Christiansen agrees.

"We don't need to weigh into the debate about is it or is it climate change or is to be better into the future, if we have a resiliant landscape," she said.

Experts expect the affected parts of the reef to recover, but depending on the coral resilience, they say that could take up to 100 years. They're hopeful that the pristine reef areas like those in the Whitsunday Passage can escape the plumes.

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