The Great Barrier Reef’s inshore coral and seagrass meadows are choking under a blanket of mud laced with toxic pesticides being washed off farmlands and many reefs are unlikely to survive the next five to 10 years.
A World Wide Fund for Nature (WWF) report on Australia’s Great Barrier Reef released on Tuesday says increasing land-based pollution, coupled with bleaching due to global warming, was seriously threatening the world’s largest coral reef formation.
“That spells catastrophe for the reef,” said the report, released on World Environment Day. “There is now serious cause for concern about the survival of the inshore reefs from Hinchinbrook Island to Port Douglas.” “Many inshore reefs are now either highly degraded or dead. They have collapsed from the effects of sediment and nutrients pouring out of our rivers,” WWF said.
The Great Barrier Reef is the world’s largest living reef formation stretching 2,000 km (1,300 miles) north to south along Australia’s northeast coast.
WWF said 28 million tons of sediment flowed into the waters of the Great Barrier Reef each year, the equivalent of 3.5 million dump trucks emptying soil onto the reef.
“Land clearing and overgrazing is responsible for the vast mjority of this sediment pollution,” said the report, adding 76.9 percent of the reef’s catchment was now grazing land compared with 10.8 percent pristine environment.
Farms with some 4.9 million cattle were depositing 18 million tons of sediment a year. Sugar cane farms which dot the coast resulted in another 1.3 million tons.
“The water is often thick and brown, like a muddy milkshake, along many parts of the coastline. Murky water is not good for reefs and seagrass which need sunlight to survive.”
WWF said thousands of tons of nitrogen and phosphorous from fertilizers, used on cane, banana and cotton farms, were being washed into the sea and poisoning marine life.
In 1994 an estimated 8,800 tons of nitrogen and 1,300 tons of phosphorous was washed into the sea around the reef. Pesticides diuron, atrazine and ametryn, used to fight weeds, rats and diseases, were also found in coastal sugar cane areas.
But at the same time up to 80 percent of freshwater wetlands, which act as filters protecting the reef from pollution run-off, have been lost due to cane growing and coastal development.