Author provided. Credit: James Kerry, ARC Centre of Excellence for Coral Reef Studies

Great Barrier Reef won't recover from bleaching

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Action to prevent rising sea temperatures from global warming is needed immediately to prevent future mass coral bleaching events, says a group of Australian scientists, who warn its unlikely the reef will ever recover from the 2016 bleaching event. Looking at three major bleaching events on the Great Barrier Reef - in 1998, 2002 and 2016 - they found that some reefs are more susceptible to bleaching than others, mostly based on patterns of sea temperatures with the cooler waters of the southern reef offering the most protection. While local management of reef fisheries and water quality helped the areas recover from bleaching events, these actions did little to protect them against extreme heat. The research comes as coral bleaching occurs on the Great Barrier Reef for the second year in a row and as scientists prepare for aerial and underwater surveys to begin this month.

Journal/conference: Nature

Organisation/s: The University of Queensland, ARC Centre of Excellence for Coral Reef Studies, CSIRO, Queensland Museum, James Cook University, The University of Sydney, University of Western Australia, Griffith University

Funder: Twenty-six of the authors are supported by funding from the Australian Research Council’s Centre of Excellence Program. Other funding support includes the Australian Commonwealth Government, the European Union, the USA National Oceanographic & Atmospheric Administration, and USA National Science Foundation. GlobColour data (http://globcolour.info) used in this study has been developed, validated, and distributed by ACRI-ST, France.

Media Release

From: Springer Nature

Bleaching causes grief to the Great Barrier Reef

Immediate action to reduce global warming is needed to protect coral reefs from severe bleaching events, according to research published in this week’s Nature. A detailed analysis of the Great Barrier Reef over the past two decades shows that extreme heat is the key driver of mass bleaching. As temperatures continue to rise, further bleaching events are likely, which may push the reef system beyond recovery.

Rising sea surface temperatures due to global warming have triggered major bleaching events in tropical coral reefs, and this damage can be potentially fatal to these delicate ecosystems. The most severe event in 2016, driven by record temperatures in the 2015–2016 El Niño event, bleached over 90% of the corals in the Great Barrier Reef.

To understand more about the effects of climate change on reefs, Terry Hughes and colleagues assessed three major bleaching events on the Great Barrier Reef in 1998, 2002 and 2016. By analysing individual reefs, the authors determine why some corals are more prone to bleaching than others. They find that the distinctive geographical footprint of bleaching is primarily driven by patterns of sea temperatures; in general, unbleached reefs were located towards the southern end of the Great Barrier Reef, where waters are generally cooler. Local management of reef fisheries and water quality offered little to no protection against extreme heat, but the authors note that these efforts may help these ecosystems to recover from bleaching events. However, it is unlikely that the Great Barrier Reef will ever fully recover from the severe bleaching that occurred in 2016, and the security of coral reefs requires urgent and rapid global action to curb future warming, the authors conclude.

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  • Springer Nature
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  • ARC Centre of Excellence for Coral Reef Studies
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  • The University of Western Australia
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