Wednesday, January 20, 2010

No Doubt Anymore

One of the most ancient and mysterious of creatures, the nautilus moves through the deep oceans with infinite patience and consummate slowness. Around for over 500 million years, this denizen of the deep, along with all other sea life, is now threatened by CO2, the gas produced in overabundance by man.

"Principal investigator Robert Byrne, a USF seawater physical chemistry professor, said the study leaves no doubt that growing CO2 levels in the atmosphere are exerting major impacts on the world’s oceans.

“If this happens in a piece of ocean as big as a whole ocean basin, then this is a global phenomenon,” Byrne said.

Adding carbon dioxide to seawater makes it more acidic, and each year the world’s oceans absorb about one-third of the atmospheric CO2 produced by human activities...

The results verify earlier model projections that the oceans are becoming more acidic because of the uptake of carbon dioxide released as a result of fossil fuel burning, said Richard Feely, a member of the research team and chief scientist of the cruise and NOAA researcher from the Pacific Marine Environmental Laboratory in Seattle.

The implications for sea life and the world’s food web are serious, Byrne said. When seawater becomes more acidic, lower concentrations of carbonate result. Because the protective shells of sea organisms are made of calcium and carbonate, more acidic waters make it more difficult for many organisms to make their shells and thrive. .

Over the next millennium, the global oceans are expected to absorb approximately 90 percent of the CO2 emitted to the atmosphere, says Christopher Sabine, chief scientist for the first leg of the cruise.

"It is now established from models that there is a strong possibility that dissolved carbon dioxide in the ocean surface will double over its pre-industrial value by the middle of this century, with accompanying surface ocean pH decreases that are greater than those experienced during the transition from ice ages to warm ages," Sabine said. "The uptake of anthropogenic carbon dioxide by the ocean changes the chemistry of the oceans and can potentially have significant impacts on the biological systems in the upper oceans."

“Estimates of future atmospheric and oceanic CO2 concentrations, based on the Intergovernmental Panel on Climate Change emission scenarios and general circulation models, indicate that by the middle of this century atmospheric CO2 levels could reach more than 500 ppm, and near the end of the century they could be over 800 ppm. Current levels are near 390 ppm, and preindustrial levels were near 280 ppm," Feely said.

Corresponding models for the oceans indicate that surface water pH would drop approximately 0.4 pH units, and the carbonate ion concentration would decrease almost 50 percent by the end of the century. This surface ocean pH would be lower than it has been for more than 20 million years.

Byrne and many other scientists expect that even if substantial reductions are made in the pace at which humans produce carbon dioxide, ocean acidification will continue for hundreds of years to come. "

James Lovelock's' dire prediction looms.

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