Dugongs are being poisoned and corals and mangroves are disappearing because of a serious decline
in water quality on the Great Barrier Reef, a scientist says.
A special edition of the scientific journal Marine Pollution Bulletin has highlighted threats to one of the world's most important natural assets from cattle grazing, sugar cane farms and urban development.Pat Hutchings, the report's co-editor and a principal research scientist at the Australian Museum, said data collected in the past 20 years had revealed a serious decline in water quality entering inshore regions of the reef.
She said an increase in sedimentation, pollutants and pesticides was killing off corals and harming marine mammals such as dugongs.
"We've got increased pesticides and heavy metals in both some of the seagrass beds and in dugongs along the coast," Dr Hutchings said today.
"In the skin and blubber tissues we've got nasty levels of organochlorines and heavy metal concentrations, and we know that numbers of dugongs are declining along the coast."
Dr Hutchings said studies had shown corals were being replaced with algae while mangroves, which support a wide range of dependent organisms, were disappearing.
"We've seen losses of
mangroves along the coast probably as a result of herbicides," she said.
"It's been accepted that there is a decline in water quality which is impacting on those coastal communities."
The reef from Cairns southward was affected however the Herbert, Burdekin and Mackay areas were bearing the brunt of water quality changes, Dr Hutchings said.
Dr Hutchings said a joint initiative between the Queensland and federal governments – the Reef Water Quality Protection Plan – was working with local communities and farmers to deliver a solution.
She said without a fundamental change in land management there would be dire consequences for the reef.
This included increases in coral bleaching events and further outbreaks of the crown of thorns starfish, which eats corals faster than the organism can grow and reproduce.
