TURN OVER A NEW REEF

摘要

Lying just below the world's largest coral reef - Australia's Great Barrier Reef - is another, dead reef. And below that another. And below that... another. Sandwiched between these layers are the fossils of soils and rainforests that grew over the former reefs when sea level dropped during ice ages. "There are probably five, six or seven reefs," says Jody Webster at Australia's University of Sydney. "If s like a sponge cake. What we have is just the top layer." By drilling cores through the present and past reefs, Webster has mapped movement through various climate shifts. "You have this system that is quite robust," says Webster. "If s seemingly able to migrate vast distances in response to habitat changes." Remarkably, he has found that when corals later re-emerge, they show striking similarities to their predecessors. Where the corals go to hide in the intervening years is something of a mystery.