Warmer ocean waters have resulted in the greatest recorded coral die off at the Great Barrier Reef in Australia, scientists studying the place said.
The worst-hit area, stretching 700 kilometre in the northern portion of the world's greatest coral reef system, has lost about two-thirds of its shallow-water corals in the past eight to nine months, based on a media release from the Australian Research Council Centre of Excellence for Coral Reef Studies at James Cook University.
"Most of the losses in 2016 have appeared in the northern, most-pristine section of the Great Barrier Reef. This area escaped with minor damage in two earlier bleaching events in 1998 and 2002, yet this time around it has been badly affected," said the centre's director, Professor Terry Hughes, who ran extensive aerial surveys at the height of the bleaching.
Warm waters can induce corals to lose or to expel algae, calcifying and turning them white.
Scientists anticipate the northern area to take at least 10 to 15 years to recover the lost corals. However they are worried that a fourth bleaching event could happen sooner and interrupt the slow recovery, in line with the centre.
The southern two-thirds of the reef "escaped with slight damage", said Professor Andrew Baird, who's also in the centre and led teams of divers to resurvey the reefs in October and November.
"On average, 6 percent of bleached corals perished in the central area in 2016, and only 1 percent in the south. The corals have now recovered their energetic colour, and these reefs are in good shape," he said.