It’s no secret the world’s largest coral reef is under significant pressure.<\/p>\n
Coral bleaching, crown-of-thorns starfish outbreaks, cyclonic weather events and warming sea temperatures \u2014 the health of Australia’s Great Barrier Reef hits global headlines regularly.<\/p>\n
In February this year, freshwater flood plumes hit reefs as far as 100 kilometres off north and Far North Queensland, highlighting the significance of yet another threat: water quality.<\/p>\n
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3,000 giant clams were killed by floodwater from the Herbert River catchment. (Supplied)<\/p>\n
At Orpheus Island, off Lucinda, around 3,000 giant clams were killed by floodwater from the Herbert River catchment.<\/p>\n
It was a significant project spearheaded by marine biologist Dr Richard Braley in the 1980s.<\/p>\n
“These organisms are stenohaline, so it means they can’t handle a big wide range of salinity changes,” Dr Braley said.<\/p>\n
“It was a sad event \u2026 they survived there for 40 years without a problem.”<\/p>\n
The floodwater was carrying sediment and the salinity dropped by around 70 per cent.<\/p>\n
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The project was launched by marine biologist Dr Richard Braley in the 1980s. (ABC News: Baz Ruddick)<\/p>\n
Manager of James Cook University’s Orpheus Island Research Station, Jenni Calcraft, said staff saw “clam bodies” floating away from the garden.<\/p>\n
“The tissue bits [were] just washing up on the beach,” she said.<\/p>\n
“Essentially they had this two-to-three metre lens of freshwater sitting on top of them for so long that it meant their tissue disintegrated and they didn’t survive.”<\/p>\n
Earlier this year UNESCO’s World Heritage Committee expressed “regret” that water quality targets for the reef had not been met.<\/p>\n
In July, it issued the Australian government with a warning that it had until February to avoid a possible “in danger” listing for the Great Barrier Reef.<\/p>\n
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Many river catchments in North and Far North Queensland saw significant flooding this year which carried flood plumes into the Great Barrier Reef Marine Park. (Supplied: JCU TROPWater)<\/p>\n
Work in the field<\/p>\n
Across north and Far North Queensland, TropWATER works in applied science when it comes to wetlands and aquatic ecosystems.<\/p>\n
Professor Damien Burrows, director of the organisation, said there had been significant “wins” in recent years with helping farmers and landholders look after the environment.<\/p>\n
On the ground, TropWATER works with canefarmers to monitor nitrogen in their fields and prevent run-off into catchments.<\/p>\n
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Damien Burrows says TropWATER had significant “wins” in recent years. (ABC News: Baz Ruddick)<\/p>\n
They also help to restore wetlands and replant riparian zones to prevent runoff into waterways.<\/p>\n
“The nutrients and sediments can create flood plumes in the wet season. They block light and affect the growth of seagrass and coral,” Professor Burrows said.<\/p>\n
“It’s an occasional occurrence, but nonetheless we are seeing that more frequently with climate change.”<\/p>\n
Professor Burrows said research shows if water quality is good, coral will be more tolerant to higher temperatures and can recover better from bleaching.<\/p>\n
Coral bleaching occurs when stressed coral expel the algae that lives in their tissue.<\/p>\n
This algae photosynthesises and feeds the coral.<\/p>\n
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Professor Burrows says water quality can be locally managed to prevent further damage to reefs. (Supplied: Angelina Pilarinos)<\/p>\n
He said while individuals or groups may not be able to control the global warming threat to the reef, water quality is a different story.<\/p>\n
“One of the things we can manage locally is water quality. That’s something that is within our control to improve,” Professor Burrows said.<\/p>\n
“It’s a very solvable problem from that point of view.”<\/p>\n
Tackling threats simultaneously<\/p>\n
Max Hirschfield is a campaigner with the Australian Marine Conservation Society, a group which advocates for improvements in policies that manage threats to the ocean.<\/p>\n
He is critical of the Australian government’s response to managing the reef, particularly water quality targets.<\/p>\n
“What’s really important here is that we don’t have a good understanding on how effective reef water quality programs are yet,” Mr Hirschfield said.<\/p>\n
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Max\u00a0Hirschfeld said the government has extended its own deadlines to meet water quality targets a number of times. (ABC News: Baz Ruddick)<\/p>\n
“There’s not a sufficient amount of publicly available data so we can’t really evaluate the efficiency.”<\/p>\n
He said all threats to the Great Barrier Reef need to be “tackled simultaneously” to give the reef the best chance of survival.<\/p>\n
“Events like cyclones, flooding, and marine heatwaves are increasing with the impacts from climate change,” he said.<\/p>\n
“They’re increasing in intensity and frequency and that’s very, really worrying for water pollution ending up on the Great Barrier Reef.”<\/p>\n
Max Hirschfield says the threats to the Great Barrier Reef need to be “tackled simultaneously”. (Supplied: Lorelle McShane)<\/p>\n