Transcript:

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Coral reefs around the world are turning white. Could there be a connection between the bleaching of the coral and global warming? I’m Jim Metzner and this is the Pulse of the Planet.

ambience: Great Barrier Reef

We’re listening to underwater sounds recorded at Australia’s Great Barrier Reef. Coral is an animal that gets oxygen and food from the plants that form a living layer on its surface. If the coral loses its layer of plants, its white skeleton shows through. The phenomenon is called 'bleaching.'

“Corals, although they're living in the tropics, are already living at their upper temperature limit, and even a small rise in temperature can affect them.”

Lucy Bunkley-Williams is a research associate with the Marine Sciences Department of the University of Puerto Rico. She says that although bleaching of coral reefs has occurred many times before, it’s usually on a small scale. Worldwide patterns of bleaching are a relatively recent phenomenon.

“We haven't been able to prove that global warming is actually occurring yet, but the coral reefs are a very sensitive system. Even small temperature rises cause problems on the reef like this bleaching that we've seen, and it could be the first indicator or the first beginning effects of global warming.”

Without their surface layer of plants, the coral reefs stop growing, and may eventually die.

“The problem is that these coral bleaching events have occurred over and over, and since it takes such a long time for the corals to recover, it may be that they bleach again before they're able to recover.”

Pulse of the Planet is presented by the National Science Foundation.

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