Great Barrier Reef experiencing `worst coral bleaching` in years

Stud reveals Great Barrier Reef coral bleaching at 95 per cent in northern section.

Sydney: The Great Barrier Reef, which is the world's largest coral reef system, off the coast of Queensland in northeastern Australia, is experiencing its worst coral bleaching in years.

According to a study by the National Coral Bleaching Taskforce, 95% of reefs from Cairns to Papua New Guinea are now severely bleached.

Out of 520 reefs, only four showed no evidence of bleaching when surveyed.

In June last year, the United Nations Educational, Scientific and Cultural Organization (UNESCO) voted not to place the reef on its endangered list.

"It's too early to tell precisely how many of the bleached coral will die, but judging from the extreme level even the most robust corals are snow white, I'd expect to see about half of those corals die in the coming month or so," Coral taskforce convener Professor Terry Hughes was quoted as saying.

Coral bleaching is the loss of intracellular endosymbionts through either expulsion or loss of algal pigmentation. It is a consequence of warmer water temperatures, causing the coral to turn completely white.