Australia’s famous Great Barrier Reef has fallen victim to its worst-ever instance of coral bleaching, with a new survey revealing that 93% of the reef has undergone the life-threatening process.
The survey by the country’s National Coral Bleaching Taskforce revealed that only a small fraction of the world’s biggest reef system has avoided bleaching entirely, according to local broadcaster ABC News.
Bleaching occurs when reefs expel the algae from their tissues — which occurs in adverse aquatic conditions like high water temperatures or pollution — placing themselves under great stress and increasing the risk of mortality.
“We’ve never seen bleaching on the Great Barrier Reef of that severity and when bleaching is that strong it affects virtually all coral species,” Professor Terry Hughes, the head of the task force, told ABC.
Hughes does clarify that the fallout “could have been much worse,” with the central and southern portions of the reef expected to regain their color in the coming months.
Corals have a remarkable ability to recover from bleaching. However, the latest instance of bleaching is far worse than the previous two the Great Barrier Reef has faced — in 1998 and 2002 respectively — when only 18% of it was “severely” bleached (compared to more than half this year) and 40% remained unaffected.
“So by those metrics this bleaching event is three or four times more severe,” Hughes said.