The Great Barrier Reef has suffered the 'largest die-off' ever recorded

Scientists assess coral mortality on Zenith Reef following the bleaching event, Northern Great Barrier Reef, November 2016. Credit: Andreas Dietzel, ARC Centre of Excellence for Coral Reef Studies.

The Great Barrier Reef has suffered the worst coral bleaching ever recorded by scientists due to higher water temperatures.

Scientists have confirmed that as much as 67% of corals have died in a 700km swathe of reefs in the northern region — the reef’s worst-hit area — according to the ARC Centre of Excellence for Coral Reef Studies report.

In an article published on The Conversation, the scientists who conducted the study wrote: “To put these losses in context, over the 27 years from 1985 to 2012, scientists from the Australian Institute of Marine Science measured the gradual loss of 51% of corals on the central and southern regions of the Great Barrier Reef.”

The map, detailing coral loss on Great Barrier Reef, shows how mortality varies enormously from north to south. Credit: ARC Centre of Excellence for Coral Reef Studies.

Coral bleaching happens when water temperatures rise for a sustained period of time.

“Most of the losses in 2016 have occurred in the northern, most-pristine part of the Great Barrier Reef. This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected,” says Professor Terry Hughes.

The damage is expected to take at least 10-15 years to regenerate, but scientists are concerned that a fourth bleaching event could happen sooner and interrupt the slow recovery.

“As global temperatures continue to climb, time will tell how much recovery in the north is possible before a fourth mass bleaching event occurs,” the researchers write.

Read more here.

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