"Stretching along the Queensland coast, the reef is an underwater wonderland home to thousands of different fish and coral species. But it is facing multiple threats.

Swathes of coral have been killed by the crown-of-thorns, a starfish which has flourished partly because of fertilisers seeping into the sea from farm run-off.

Extreme weather has also damaged the reef, while increased carbon in the atmosphere has made the water too acidic, leading to coral bleaching."

Jon Donnison reports for BBC News October 22, 2014. [2]