Posted on: Wednesday, March 30, 2005

UH studying possible coral reef link to global warming

Associated Press

Hawai'i's coral reefs produce carbon dioxide when they calcify and researchers from the University of Hawai'i are trying to figure out whether the emissions contribute significantly to global warming.

Scientists from UH have been studying whether Hawai'i's coastal zones emit carbon dioxide or absorb it in large amounts.

Studies have shown about two billion tons of carbon are absorbed by the open ocean each year, UH oceanographer Fred Mackenzie said. In contrast, he said, about eight billion tons of carbon are released annually into the atmosphere by fossil fuel burning and deforestation.

But the pattern of carbon uptake and release in coastal zones is still up for debate, he said.

Mackenzie and his colleagues have been measuring the exchange of carbon dioxide between the ocean and atmosphere at Hilo Bay, Enchanted Lake and Kane'ohe Bay.

Data from the locations show "all three on an annual basis are a net source of carbon dioxide to the atmosphere, not a sink like the open ocean," Mackenzie said.

The team has not yet determined how much carbon dioxide is released by Hawai'i's reefs, but has predicted that coastal zones all over the world have been adding carbon dioxide to the atmosphere during the last several hundred years.

The researchers recently extended their studies to Kailua Bay.