Great Barrier Reef loses more than half its coral cover

Source: The Guardian

Coral cover in the Great Barrier Reef has dropped by more than half over the last 27 years, according to scientists, a result of increased storms, bleaching and predation by population explosions of a starfish which sucks away the coral's nutrients.

At present rates of decline, the coral cover will halve again within a decade, though scientists said the reef could recover if the crown-of-thorns starfish can be brought under control and, longer term, global carbon dioxide emissions are reduced.

"This latest study provides compelling evidence that the cumulative impacts of storms, crown-of-thorns starfish (Cots) and two bleaching events have had a devastating effect on the reef over the last three decades," said John Gunn, chief executive of the Australian Institute of Marine Science.

Coral reefs are an important part of the marine ecosystem as sources of food and as protection for young fish. They are under threat around the world from the effects of bleaching, due to rising ocean temperatures, and increasing acidification of the oceans, which reduces the corals' ability to build their calcium carbonate structures.

Read more: http://www.guardian.co.uk/environment/2012/oct/01/great-barrier-reef-coral-cover

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Acidification of the ocean is another effect of rising carbon dioxide levels, caused by fossil fuel burning.