13 March 2009

Queensland oil spill: birds and turtles at risk

By
Cosmos Online
Thirty tonnes of oil that spilled along the Queensland coast on Wednesday are damaging sensitive marine ecosystems, experts say – especially birds, turtles and intertidal organisms.
Bird getting cleaned up

Birds at risk: Shorebirds, including pied oystercatchers and stone-curlews, are the species most likely to come in contact with the oil, say experts. Credit: AFP

SYDNEY: Thirty tonnes of oil that spilled along the Queensland coast on Wednesday are damaging sensitive marine ecosystems, experts say – especially birds, turtles and intertidal organisms.

The spill occurred when the Hong Kong-based cargo ship Pacific Adventurer, battered by the swells of tropical cyclone Hamish, dropped 31 containers of ammonium nitrate into the sea.

The containers remain sealed, but punctured the ship’s hull and released the oil into Moreton Bay, a marine sanctuary, near Brisbane.

Severe weather conditions

The oil is now smothering more than 50 km of coastline. Although not large by the standards of other international disasters, it is still causing significant damage to the environment.

“I think it’s pretty severe with the weather conditions the way they are, it’s going to spread up and down the coast at the whim of Mother Nature,” said Leonie Anderson, an ecotoxicologist and the coordinator of the Port Curtis Integrated Monitoring Program, which assessed a 25-tonne Queensland oil spill in 2006.

“Instead of being a situation where the [wildlife] can control and recover, [the oil] is just going to come back to clean up, and it’s not an easy task,” she said.

Oil spills are particularly problematic because they do not disappear quickly, said Ravi Naidu, the director of the University of South Australia’s Centre for Contamination Assessment and Remediation, in Adelaide.

“The problem with oil is that it doesn’t dilute, it doesn’t mix… this can lead to long-term contamination of the coastal region and seawater,” he said.

Ross Coleman, a marine ecologist with the University of Sydney, said the area’s shorebirds, including pied oystercatchers (Haematopus longirostris) and several species of stone-curlews, are those most likely to come in contact with the oil. This will clog up their feathers, and if not treated, could lead to a slow death.

Risk to turtle eggs

Mike Kingsford, a marine biologist with James Cook University in Queensland, said that volatile compounds in the oil can also directly kill intertidal organisms like snails and sandhoppers.

In addition, loggerhead turtles (Caretta caretta), which the Australian government lists as an endangered species, lay their eggs at the top of the beach, in harm’s way of the oil.

“Eggs are porous to some extent, and they need to respire, so pouring oil over them is certainly a bad thing,” Kingsford said.

The oil will eventually solidify into tar, which is mostly benign and less likely to cause damage. At that stage “it’s more likely to be visual pollution than pollution that will affect organisms,” Kingsford said.

The ammonium nitrate containers remain sealed, but could endanger fish if they rupture. Naidu said the containers pose less risk to wildlife, though, because unlike oil, ammonium nitrate will dilute in water.

Aircraft equipped with radar equipment have been sent to search for the missing containers.

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