A recent study has found that over 40% of individual corals monitored around One Tree Island in the Great Barrier Reef were killed due to heat stress last year, marking the most widespread coral bleaching outbreak on record. The research team tracked 462 coral colonies and observed “catastrophic” scenes at the reef.
According to Professor Maria Byrne, a marine biologist at the University of Sydney, who has been researching the island for 35 years, witnessing massive colony deaths was devastating. She notes that climate change is a major concern, stating “we have been trying to get the message across about climate change for ages.”
The study found that coral cover in the Capricorn-Bunker sector dropped by 41% in November, with similar falls recorded in other areas of the reef. One government scientist described the scene as a “graveyard of corals.” The research team used temperature loggers, video, and direct observations to track the welfare of 12 different types of coral.
The scientists warn that while some bleached corals can recover, others will die. A genus of coral known for its vibrant polyps was observed bleaching and then contracting a flesh-eating disease. The researchers emphasize that heat stress is a major threat to the reef’s health, particularly during peak months like March.
WWF-Australia’s head of oceans, Richard Leck, warns that another back-to-back bleaching event is possible this summer due to increased heat stress in the north and south of the reef. He stresses the importance of accurate reporting on the reef’s condition and renewed efforts to protect it from climate change.
The Australian government has been asked by UNESCO to report on the reef’s health, and Leck emphasizes the need for immediate action to mitigate the effects of climate change on this world heritage site.
Source: https://www.theguardian.com/environment/2025/jan/22/catastrophic-great-barrier-reef-hit-by-its-most-widespread-coral-bleaching-study-finds