The Great Barrier Reef Is Losing Its Ability to Recover from Bleaching Events

If you hadn’t heard, things aren’t looking too rosy for the world’s reefs. Warmer oceans have led to an uptick in global coral bleaching events, ocean acidification is decreasing the amount of free carbonate ions available to reef building species, and the billions of bits of plastic that coat reefs around the globe have led to an explosion of coral infections.

These climate change-induced effects have taken a particularly devastating toll on the Great Barrier Reef off the east coast of Australia. At 1,400 miles long, the Great Barrier Reef is by far the largest in the world, but half of its coral has died in the past two years after unprecedented back-to-back bleaching events.

This is bad enough, but a new study published today in Science Advances claims that the Great Barrier Reef is also losing its ability to recover from bleaching events and infections, which has precipitated its destruction.

A group of Australian scientists analyzed data from 1992 to 2010 and found that the average rate of recovery across the Great Barrier Reef showed a six-fold decline during that time period. Juan Ortiz, a marine biologist at the University of Queensland, said that “this is the first time a decline in recovery rate of this magnitude has been identified in coral reefs.”

The researchers attributed the failing recovery mechanisms of the reef to a combination of bleaching events, increasingly powerful cyclones, and poor water quality.

Although reefs only cover about 1 percent of the seafloor, they support about a quarter of all ocean life and act as a tidal barrier for coastlines. The complete collapse of our world’s reefs would be devastating for ocean ecosystems and human coastal populations.

Things look bleak for the Great Barrier Reef right now, but University of Queensland marine biologist Peter Mumby said that the effective management of reef ecosystems can help to nurse them back to health. In particular, Mumby noted that coral recovery greatly depends on the quality of the water in its local environment, so conservation efforts that focus on improving the quality of water in a given region could hasten reef recovery.

Indeed, the Belize Barrier Reef was recently removed from a list of endangered ecosystems through active management and progressive conservation policies implemented by the Belizean government. Similar principles could save the Great Barrier Reef as well, but action must be taken soon.

Ortiz said that ultimately the long-term protection of coral reefs depends on our ability to dress climate change on a global scale, concluding that “the future of the Great Barrier Reef is threatened without further local management to reduce chronic disturbances and support recovery, and strong global action to limit the effect of climate change."