Ocean quest: The race to save the world's coral reefs

Last week, scientists issued their latest, grim assessment of the world's coral reefs. But as Steve Connor reports from Florida, extraordinary new ocean 'reseeding' techniques mean there may still be time to halt – or even reverse – the destruction of mother nature's marine marvels

Thursday, 17 July 2008

Coral reefs are often described as the tropical rainforests of the oceans. But marine biologists sometimes use another analogy: that of the canary in the coalmine. These birds were used by miners as an early warning for lethal gas; corals, too, are extraordinarily sensitive to environmental change. For Nancy Knowlton, a scientist at the Smithsonian Natural History Museum, it's an apt description: "If that's the analogy, then the canary has passed out on the floor of the cage. Coral reefs are potentially immortal. They only have to die if we make them."

And that's just what we seem to be doing. In the 25 years that Knowlton has been studying the reefs, she has witnessed all the signs of their terminal decline. They are being degraded at a rate of 2 per cent a year. About a fifth of the world's stock has already gone, and nearly half of the remainder is in danger of disappearing within the next 20 years. And like so many other experts in her field, Knowlton is worried: a lethal combination of pollution, predators, disease, rising sea temperatures, over-fishing and the acidification of the sea have put our coral reefs on the critical list.