Scientists record largest coral die-off ever at Great Barrier Reef

Warming sea temperatures during the months of March and April has caused in the worst coral bleaching event ever recorded at the Great Barrier Reef, with two-thirds of a 435 mile (700 km) stretch of coral dying off over the last several months, scientists announced on Tuesday.

According to Reuters and AFP, the northern third of the 1,400 mile (2,300 km) World Heritage site was the most affected in what experts are calling the worst die-off in the reef’s history, and most likely the largest such event ever recorded, due to the size of the Great Barrier Reef.

“Most of the losses in 2016 have occurred in the northern, most-pristine part of the Great Barrier Reef,” Terry Hughes, Director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University and one of the researchers behind the new study, said in a statement.

“This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected,” added Hughes, who along with a team of colleagues conducted a series of aerial surveys of the reef throughout the course of the bleaching event.

scientists coral reef

A scientist assessing the state of the reef.

News isn’t all bad, however, according to researchers

The worst affected area, the researchers found, had lost an average of 67% of its shallow-water corals over the past eight or nine months. Further to the south, the news was better, as the central and southern portions of the Great Barrier Reef experienced significantly less coral death.

“The good news is the southern two-thirds of the Reef has escaped with minor damage,” said the ARC Centre’s Professor Andrew Baird, who lead a team of divers that surveyed the reefs during the months of October and November. An average of 6% of bleached corals died off in the center of the reef, and just 1% in the south, he added. “These reefs are in good condition.”

Craig Stephen, the manager of one of the Great Barrier Reef’s largest live-aboard tourist operations, called the findings “welcome news for our tourism industry.” According to the ARC Centre, the Great Barrier Reef’s tourism industry employs approximately 70,000 people, and brings in about $3.9 billion US ($5.2 billion Australian) in income annually, Reuters added.

At 134,400 square miles (348,000 square km), the Great Barrier Reef is the largest coral reef on Earth, and when the water surrounding it becomes too warm, the coral is forced to release living algae – causing it to turn white and become “bleached.” Bleaching occurs naturally, and in most cases, coral that is mildly affected can recover, but conservationists are concerned that rising sea temperatures caused by global warming are amplifying the damage caused by bleaching.

“Climate change is killing the Great Barrier Reef,”  Charlie Wood, director of  anti-fossil fuels movement 350.org, told Reuters via email. “The continued mining and burning of coal, oil and gas is irreparably damaging the climate. If we want our kids to enjoy the Great Barrier Reef for generations to come, we must act now to keep fossil fuels in the ground.”

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Image credit: Greg Torda, ARC Centre of Excellence for Coral Reef Studies