Great Barrier Reef has survived 5 near-death events

The Great Barrier Reef off Australia’s northeastern coast has proved to be extremely resilient as a new study reveals that the world’s largest reef system has survived five events in the past 30,000 years.

But scientists are not sure that the reef is resilient enough to survive the current crisis caused by rising ocean temperatures and coral bleaching. The study published in Nature Geo-Science reconstructed the evolution of the reef as it has adapted to environmental changes in sea levels and temperatures by migrating.

“Our study shows the reef has been able to bounce back from past death events during the last glaciation and deglaciation,” University of Sydney’s Jody Webster and lead author of the study said to Science Daily.

The first two near-death events — the first one occurring about 30,000 years ago during a glacial period — were due to low sea levels that caused the killing of coral from air exposure. The reef adjusted by migrating seaward which allowed the system to recover.

The next two events occurred during deglaciation that saw rising sea levels and the drowning of the reef, which then adjusted by migrating landward.

The final event occurred about 10,000 years ago which saw rising sea levels and an influx of sediment.

The study found the reef has been sensitive to sediment fluxes and more research is needed on how current practices are affecting sediment input and water quality, Webster said.

“I have grave concerns about the ability of the reef ... to survive the pace of change caused by the many current stresses and those projected into the near future,” he said.