Picture Credit: Science News (Pinterest)
Australia's Great Barrier Reef has suffered catastrophic coral bleaching, with new research revealing an alarming loss of coral life. The summer of 2024 marked the reef's worst on record, with ocean temperatures hitting unprecedented highs, driven by global warming and intensified by the El Niño weather pattern. El Niño is a natural weather pattern where the surface waters in the central and eastern parts of the Pacific Ocean warm up, it lasts for several months and is part of a larger cooling and heating pattern called the El Niño-Southern Oscillation (ENSO). This heat stress is now supercharged by the effects of global warming and caused the reef’s seventh mass bleaching event, leaving more than half of the monitored coral colonies near One Tree Island in the southern reef dead by mid-year.
Bleaching occurs when stressed corals expel algae, their vital life source, leaving them ghostly white and vulnerable. The study by the University of Sydney tracked 462 coral colonies, of which 52% perished, with some species experiencing up to 95% mortality. Researchers also reported the onset of colony collapse, where coral skeletons detach and turn to rubble, and outbreaks of black band disease further exacerbated the crisis. Shawna Foo, a marine scientist and co-author of the study comments, “Seeing the impacts on a reef that has largely avoided mass bleaching until now is devastating”.
Climate change is a driving factor of the deaths of this once magnificent and tenacious marine habitat. Its not just the detrimental effects of algae loss that the coral reef has to deal with, due to global warming ocean acidification also has a profound effect on the ability of corals to recover. Corals use calcium carbonate to formulate their coral skeleton formation, however ocean acidification reduces the availability of this compound, slowing the recovery process after bleaching.
The Great Barrier Reef, stretching over 133,000 square miles, is critical to marine biodiversity and a cornerstone of Australia’s economy. However, even remote, pristine areas once thought to be resilient were not spared from this devastation. Scientists warn that mass bleaching events are becoming increasingly frequent, highlighting the urgent need for global climate action. Without decisive steps to reduce emissions and limit warming, the future of this natural wonder remains in grave jeopardy.
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