The Great Barrier Reef has been called the most biodiverse of all World Heritage sites by the United Nations. The largest reef on Earth is located off the coast of Queensland in the Coral Sea.
Already suffering from bleaching events caused by rising ocean temperatures from climate change, the reef may now be smothered by a mix of mud and fertilizer as a result of record breaking rainfall, which followed record deadly heatwaves and drought in Queensland, Australia.
Massive plumes of polluted floodwater spanning the entire coast of north-east Queensland are encroaching on the outer reaches of the Great Barrier Reef, sparking a fresh threat to the beleaguered natural wonder.
Scientists are surveying the marine fallout from the state's latest natural disaster, with the spectacle of muddy waters fanning out from swollen rivers of the Whitsundays to Cape Tribulation captured in satellite images that have been shared around the world.
Researchers said the flood run-off, which likely included nitrogen and pesticide chemicals, were flowing as far as outer-shelf reefs 60 kilometres from the Queensland coast, piling pressure on coral already stressed by an unprecedented run of recent mass bleaching events.
Dr Frederieke Kroon, who leads the Australian Institute of Marine Science's (AIMS) water quality team, said the flood plumes going out to the reef covered "an extraordinarily large area".
The main effect of the plume will be a decrease of sunlight reaching the corals and seagrass. According to researchers the plumes can kill the reef if the plumes linger.
xWow. This is @NASA_Landsat imagery from the aftermath of the Queensland floods. pic.twitter.com/jZby9GjocB
— Mark Doman (@MarkDoman) February 12, 2019'They're all dead': Queensland floods decimate native wildlife
The wide-spread losses don’t surprise James Cook University wildlife biologist Stephen Williams.
But he warns the loss of so much wildlife risks damage to the broader ecosystem and its ability to recover.
“The healthy functioning of the landscape is sum product of everything that lives there – all of the insects, all of the birds and mammals,” he told AAP.
Prof Williams said kangaroos, rodents, hopping-mice, bandicoots and echidnas and dunnarts were all likely to have been impacted by the floods.
The endangered Julia Creek dunnart, whose range is limited to the Mitchell grass plains, much of which was badly flooded, may be one animal pushed to the brink.
“When you have such a large-scale flood that completely covers the landscape in many areas, there’s not really anywhere small animals can get to – they’d be lucky to survive,” he said.
“There’s no refuge, there’s nowhere to hide, so basically the whole population in that area probably gets wiped out.”
Two RAR soldiers rescue a wallaby from floodwaters in North Queensland.Up to 500,000 drought-stressed cattle killed in Queensland floods
When the downpour finally came last week, graziers were elated. Now it’s feared up to 500,000 cattle, mostly from severely drought-stressed herds, have been killed in widespread flood waters.
The full extent of the losses won’t be known for weeks; some properties remain underwater and the flood waters are moving south. But the agricultural industry’s peak body says the situation has already become “a massive humanitarian crisis”, affecting an area twice the size of Victoria.
After a prolonged drought, some rural parts of Queensland received three years’ worth of average rainfall in a week.
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Guerin said the full extent of livestock losses would not be known until the water fully recedes, but some estimates put losses up to 500,000 out of 10.5m head of cattle in Queensland.
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“The loss of hundreds of thousands of cattle after five, six, seven years of drought is a debilitating blow not just to individual farmers, many of whom have lost literally everything, but to rural communities.
“Some farmers have lost everything, literally everything, except an ever-growing debt, and our first priority is to make sure that they are OK,” he said.