Great Barrier Reef experiences largest coral die-off, scientists say

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A site of vivid beauty, the Great Barrier Reef is one of our planet's natural wonders and home to the largest collection of coral reefs on earth.

Now, scientists in Australia have reported the "largest die-off of corals ever recorded", with the main culprit being 'bleaching'. In the worst hit area, the Great Barrier Reef had seen an average of 67 percent of "shallow water corals" die over the past eight to nine months.

"Most of the losses in 2016 have occurred in the northern, most-pristine part of the Great Barrier Reef," Terry Hughes, director of the Australian Research Council (ARC) Centre of Excellence for Coral Reef Studies, said in a news release. "This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected," Hughes added.

Bleaching takes place when "abnormal" conditions – such as increased sea temperatures – result in coral getting rid of very small photosynthetic algae, according to the ARC.

When this happens, the corals 'bleach' and turn white. While they can recover if the sea temperature falls again, they can die if it doesn't.

There were some positives in the recent findings, however.

"The good news is the southern two-thirds of the Reef has escaped with minor damage," the ARC's Chief Investigator Andrew Baird said.

"On average, 6 percent of bleached corals died in the central region in 2016, and only 1 percent in the south. The corals have now regained their vibrant color, and these reefs are in good condition."