Some Coral Reefs May Not Be in Hot Water
News story originally written on February 7, 2008

Coral animals need to live in seawater that’s warm, but not too warm. As climate changes causes seawater to warm, some corals become less healthy.

Now scientists have found that areas of the ocean might have ways to keep from warming too much. If so, then some of the world's largest coral reefs might be protected from climate change.

Scientist Joan Kleypas led a team to study an area of the Pacific Ocean northeast of Australia. They looked at records of ocean temperature and coral health. They also used a climate model to study how ocean temperatures can change.

They found that while other areas of the oceans have warmed in the past few decades, the temperature has not changed much in this area of the Pacific Ocean. And the coral reefs there have stayed pretty healthy.

Some scientists think that oceans might have ways to stop the water from warming beyond a certain point. What could keep the water from warming? If water warms a little, more water will evaporate. Evaporation takes heat out of the water. It also can cause more clouds to shade the water and can cause more wind. Both shade and wind can cool the surface. In some areas, warmer water changes ocean currents that mix in cooler water. 

Corals in other places may not be so lucky. Corals that live in slightly cooler water will have much more temperature change as the water warms towards the limit. In addition to warming seawater, coral reefs face many other threats - carbon dioxide, diseases, overfishing, and pollution to name a few.

"Warming waters are just one part of the picture, but they are an important part," says Joan Kleypas.

Last modified March 12, 2008 by Lisa Gardiner.

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