Scientists mobilise as bleaching resumes on Great Barrier Reef

Griffith University researchers will further their fight to protect the Great Barrier Reef after new research revealed its resilience is rapidly waning.

The collaborative study between institutions across the world, published in the prestigious journal Nature today, examined whether past exposure to bleaching in 1998 and 2002 made reefs any more tolerant in 2016. Sadly researchers found no evidence that past bleaching makes the corals any tougher.

Associate Professor Guillermo Diaz-Pulido and Dr Emma Kennedy, of Griffith’s School of Environment and the Australian Rivers Institute, contributed key coral bleaching data from the southern Great Barrier Reef to the paper, amid current concerns about coral bleaching occurring for a second year in a row.

“Our group looks at what happens after the coral dies from beaching and when it gets invaded by seaweed. That’s important because seaweeds could inhibit the recovery of the coral, ultimately affecting the resilience of the reef, and its precious future” Associate Professor Diaz-Pulido says.

Coral researchers are now conducting aerial and underwater surveys along the reef and elsewhere in Australia as bleaching reappears, following last year’s event when scorching temperatures caused the worst coral bleaching on record.

Teams will spend the next few weeks in the air and underwater measuring the extent of the damage from this summer compared to last.

“We’re hoping that the next 2-3 weeks will cool off quickly, and this year’s bleaching won’t be anything like last year. The severity of the 2016 bleaching was off the chart,” explains lead author of the study, Professor Terry Hughes, from the ARC Centre of Excellence for Coral Reef Studies at James Cook University.

“It was the third major bleaching to affect the Great Barrier Reef, following earlier heatwaves in 1998 and 2002. Now we’re gearing up to study a potential number four.”

The study also reveals that protecting reefs from fishing, and improving water quality, makes no difference to the amount of bleaching during extreme heatwaves, although it might help them recover in the longer term.

“It broke my heart to see so many corals dying on northern reefs on the Great Barrier Reef in 2016,” says Prof. Hughes, who led the expansive aerial surveys. “With rising temperatures due to global warming, it’s only a matter of time before we see more of these events. A fourth event after only one year would be a major blow to the reef.”

The paper Global warming and recurrent mass bleaching of corals, by 46 co-authors, appears today in the journal Nature.

Photo credit: Greg Torda, bleached coral north of Townsville, March 2017.