A new study by the Australian Institute of Marine Science unveiled parts of the Great Barrier Reef are suffering unprecedented coral mortality, and the worst fear is that such damage could be widespread. The surveys conducted on 12 reefs showed up to 72% of coral had died, the devastating result from mass bleaching, two cyclones, and flooding over the past year.
Worst Ever Decline in Coral
According to data from Australian research, this year’s coral die-off is the worst in decades. One northern section of the reef reported the death of about one-third of hard coral, a development deemed as the “largest annual decline” for 39 years of government monitoring by the Institute. This was during a summer that recorded extreme heat stress surpassing previous bleaching events.
Bleaching Events and Rising Temperatures
The direct cause behind the disastrous coral bleaching is constantly rising sea temperatures that force the coral to expel the algae on which it depends for nourishment. When such heat stress becomes intolerable, the coral turns white and finally dies without recovering. This year’s event makes it the fifth occasion in the past eight years that the reef has suffered this crisis.
Acropora Coral is at the highest risk
Among the species affected, the fast-growing acropora coral suffered the highest mortality rate. Being among the first corals that bleach, acropora is also one of the most significant for reef growth, making its loss all the more troubling. Lead researcher Mike Emslie referred to the heat stress experienced this summer as among the worst on record for the reef.
Concern about Irreparable Damage
Richard Leck, the World Wildlife Fund-Australia’s head of oceans, expressed his concern that the situation might be worse than initially feared. He noted that while the reef can recover, the repeated toll of extreme weather events is pushing it past its limits. “The Great Barrier Reef can bounce back but there are limits to its resilience,” he said. “It can’t get repeatedly hammered like this. We are fast approaching a tipping point.”
Need for Deeper Climate Action
According to Leck, the survey findings reinforce the urgent need for Australia to set tougher climate policies. He urged Australia to set a commitment to reduce emissions by at least 90% below the levels in 2005 by 2035 and to shift away from fossil fuels. With Australia being a key player globally in the exportation of coal and gas, Leck warned that the Great Barrier Reef cannot survive such harsh conditions without immense political and environmental change.
A Grim Future for the Reef?
Although such a high mortality rate only applies to a relatively small portion of the reef, there is a fear that similar rates are going to occur across the majority of the Great Barrier Reef when the report is published fully next year. Experts are not done warning and claiming that the coral ecosystem, one of the biodiverse areas globally, could reach its breaking point.
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