29 May 2018 - The Great Barrier Reef might be more resilient than we thought, surviving five so-called “death events” in the past 30,000 years. But the current environmental troubles facing the iconic reef could be the sixth and possibly final death event, researchers warn. A new study carried out by scientists led by researchers from the University of Sydney used fossilized coral at the edge of the continental shelf to look back at the history of the reef and the environmental pressures it has faced, like changes in sea level and temperature.
The team of scientists reconstructed how the reef shifted and evolved during the past 300 centuries in the face of events like the last glacial period. In the past, the reef has shifted along the sea floor to deal with changes in its environment, moving either seaward or landward depending on whether the level of the ocean was rising or falling, the researchers found. Based on fossil data from cores drilled into the ocean floor at 16 sites, they determined the Great Barrier Reef was able to migrate between 20 centimeters (7¾ inches) and 5 feet per year — showing an impressive agility.
The findings — published in the journal Nature Geoscience — suggest that the reef may be more resilient than once thought. But despite the good news, it has likely never faced an onslaught quite as severe as today and the rapid speed of ecological change, researchers said.
“I have grave concerns about the ability of the reef in its current form to survive the pace of change caused by the many current stresses and those projected into the near future,” said the study’s lead author, University of Sydney School of Geosciences associate professor Jody Webster.
The World Heritage-listed site, which attracts millions of tourists every year, is reeling from successive bouts of coral bleaching due to warming sea temperatures linked to climate change.