Great Barrier Reef coral bleaching worsens as scientists fear heatwave's impact

Extract from The Guardian

Images released by Greenpeace show newly bleached coral at reef between Port Douglas and Cairns

Photos taken by marine biologist Brett Monroe Garner on the Great Barrier Reef between Port Douglas and Cairns show bleaching of corals he said were ‘full of colour’ just months ago. Photograph: Brett Monroe Garner/Greenpeace

Joshua Robertson

Friday 10 March 2017 06.00 AEDT 

More evidence of coral bleaching on the Great Barrier Reef has emerged ahead of surveys that will confirm whether an underwater heatwave has caused widespread damage for an unprecedented second year in a row.
Photos and footage taken by marine biologist Brett Monroe Garner at a reef between Port Douglas and Cairns – south of the hardest-hit northern section of the reef last year – indicate severe bleaching of corals he said were “full of colour and life” just months ago.
The images, released by Greenpeace on Friday, add to what the US National Oceanic and Atmospheric Administration has described as reports of “scattered coral bleaching along a large stretch” of the reef, from Mackay in the south to the far north.

The scale of bleaching will be confirmed through surveys by reef scientists and the Great Barrier Reef Marine Park Authority, which is due to release some findings on Friday from aerial inspections on Thursday.
The prospect of widespread damage compounds fears for the survival of coral already stressed by the reef’s worst ever bleaching event in 2016, which killed off 22% of coral in one hit.

Coral recovery has been challenged by stubbornly high sea surface temperatures over the 12 months since, including through winter.
It follows pictures of newly bleached coral taken in recent weeks at Moore Reef, near Cairns, by the reef scientist Tyrone Ridgway, as well as by divers further south near Palm Island.
Garner, who has been documenting the bleaching with Greenpeace, said: “I’ve been photographing this area of the reef for several years now and what we’re seeing is unprecedented.
“In these photos nearly 100% of the corals are bleaching and who knows how many will recover? Algae is already beginning to overgrow many of the corals.
“Just a few months ago, these corals were full of colour and life. Now, everywhere you look is white. The corals aren’t getting the chance to bounce back from last year’s bleaching event. If this is the new normal, we’re in trouble.”

Images released by Greenpeace add to what the US National Oceanic and Atmospheric Administration has described as reports of ‘scattered coral bleaching along a large stretch’ of the reef. Photograph: Brett Monroe Garner / Greenpeace

The bleaching has prompted Terry Hughes, a leading reef scientist at James Cook University who is also with the National Coral Bleaching Taskforce, to embark on a week-long aerial survey of the reef from next Wednesday.
The survey will replicate one last year that drew global attention to the extent of damage to the natural wonder.
He said indications from underwater thermometers were that although sea surface temperatures were lower than this time last year, they had been above average over the last year, including through winter.
Bleaching occurs when warm waters prompt coral to expel algae living within their tissues, turning white.

The coral may die in the six to 12 months after bleaching, meaning the level of mortality on the reef will not be determined until later in the year.
The world heritage-list reef was spared an “in danger” listing by Unesco in 2015 but environmental groups argue it remains on the organisation’s “watch list”.
The Australian and Queensland governments, which are obliged to show how they are jointly managing the reef’s long-term conservation, acknowledge climate change is its main threat.
The Queensland Labor government, which is focused on improving water quality after its bid to pass tree-clearing laws to curb emissions – a key plank of Australia’s reef conservation plan – failed, has urged its federal counterpart to price carbon.
However, the federal environment minister, Josh Frydenberg, at the start of a review of the government’s climate change policies earlier this year, was forced to rule out pricing carbon after a brief internal revolt.
The Greenpeace campaigner Alix Foster Vander Elst said the Australian and Queensland governments should rethink their support of the giant proposed Adani coalmine, given its potential contribution to climate change.
“We have on our doorstep the clearest signal that climate change is happening, and that governments aren’t moving fast enough to stop it,” Elst said. “Tackling climate change is the only real solution here and that starts by stopping public funding for climate-killing coal projects.”