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- Flood water in Queensland has swept away sediment and pollution.
- Large plumes have reached the Great Barrier Reef.
- The plumes could prevent the light from reaching the reef or causing a harmful algal bloom.
The Great Barrier Reef is facing another threat.
Scientists claim that runoff from flooding that recently devastated parts of Queensland has created large, polluted plumes that reach the reef.
Frederieke Kroon, who heads the water quality team at the Australian Institute of Ocean Sciences (AIMS), told the Australian Broadcasting Corporation that plumes, visible on satellite images, covered "an extremely vast area".
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"If you look at remote sensing imagery, the one that stands out right now is the Burdekin, which is the largest river in this region," she said. "But over the past two weeks, other rivers have also produced significant flood plumes, which have since dissipated, but still affect large areas of the Great Barrier Reef." . "
Floods in northern Queensland, Australia, are causing plumes in the Coral Sea that could harm the Great Barrier Reef. The plume of the Burdekin River can be seen here in this image of NASA Worldview.
(NASA)
Unprecedented monsoon rains more than two weeks left much of northeastern Queensland under water. Nearly 3,000 homes were damaged in the town of Townsville. At least three deaths have been attributed to the floods. Hundreds of thousands of cattle were also killed in the flood.
Damage estimate exceeded one billion dollars (US $ 700 million), reports the Brisbane Times.
At present, much of the floodwater flows in the Coral Sea over a distance of 35 miles and is heading towards the Great Barrier Reef.
The reef is a United Nations World Heritage Site which covers an area of 133,000 square miles and is the largest ecosystem of coral reefs in the world.
Previous threats to survival included mass laundering episodes in 2016 and 2017.
(MORE: The Great Barrier Reef is irreparably changed by the massive destruction of corals, according to a study)
Kroon said the flood plumes could kill corals and seagrass beds.
A plume of the Burdekin River in Queensland, Australia, floods the old reef into the Great Barrier Reef.
(Matt Curnock / Tropwater JCU)
"The two things that concern us the most are the sediments from erosion in the watershed, transported with rainwater in the rivers to the reef and nutrients such as nitrogen and phosphorus, "she said.
Because the winds have been weak in the area, the plumes do not dissipate quickly.
Jane Waterhouse, scientist at the TropWATER research unit of James Cook University, told the BBC: "The biggest concern at the moment Is this light reduced? If it persists much longer, in some cases we may even witness a choking of the system. "
The nutrients in the plume could also cause more growth of the algae, which would also harm the reef.
One of the possible benefits of plumes is that colder flood waters could help prevent underwater heat waves that "cook" coral, Kroon said.
"If you want to have a setback to the story, it's yes, but it still disrupts the reef a lot. [after] the bleaching and cyclones we've had in the last two years. The reef does not even really have time to recover from these disturbances because it is hit each year by something pretty much. "
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