Final results of aerial survey reveal 93% of GBR hit
Further surveys of the Great Barrier Reef have confirmed scientists worse fears - last month DIVE reported that the northern section of the world's largest living structure had suffered extensive bleaching, this week follow-up research shows as much as 93 per cent of the total structure has been hit.
The final results of extensive aerial and underwater surveys reveal that only seven per cent of the reef has escaped. It varies along the 2,3000km of the reef from very severe in the north to moderate in the central section with little damage in the south.
'We've never seen anything like this scale of bleaching before,' said Professor Terry Hughes, convenor of the National Coral Bleaching Taskforce. 'In the northern Great Barrier Reef, it's like 10 cyclones have come ashore at once.'
Australia's Environment Minister Greg Hunt said it was 'absolutely clear that there is a severe coral bleaching event occurring not just in the Great Barrier Reef but throughout many parts of the Pacific'.
Hughes said the bleaching began in Hawaii late last year and had already affected several Pacific islands.
'Right now, New Caledonia, the Coral Sea, the northern half of the Barrier Reef and New South Wales are bleaching severely, and western Australia is quickly catching up,' he told AFP.
Bleaching occurs when abnormal environmental conditions, such as warmer sea temperatures, cause corals to expel tiny photosynthetic algae, draining them of their colour.
Corals can recover if the water temperature drops and the algae are able to recolonize them.
Hughes said while bleaching had been linked to El Ninos, which generally occur every four to six years, 'it wasn't until 1998 that one finally caused a bleaching event to happen' on the Great Barrier Reef.
'So the issue is global warming,' Hughes told AFP, saying the link between water temperature and the severity of the bleaching was clear.
Hughes said the impact on the Great Barrier Reef would have been even worse had not a tropical cyclone which smashed into the Pacific island of Fiji in February brought rain and cooler weather to parts of Queensland.
'If you think about it, being rescued by the vagaries of a cyclone is a fairly precarious place to be,' he added.