January 21, 2010

Greenhouse gases are amping ocean acidification, 15-year study shows

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If there is any doubt that greenhouse gas emissions have extensive, far-reaching effects on our planet, the newly released results of a careful, long-term study should put any remaining confusion to rest. New research shows the Pacific Ocean is becoming more acidic, weakening shellfish and other marine life at a scarily fast clip – resulting in a 6 percent jump in ocean water acidity over the past 15 years in the top 300 feet of the ocean.

rita_hibbardwebOcean acidification is caused by carbon dioxide from cars, factories and power plants that causes global greenhouse effects and also dissolves in the ocean, writes Seattle Times science reporter Sandi Doughton.

The process makes seawater slightly more acidic, and also gobbles up carbonate, a basic building block of seashells. The higher acid environment dissolves shells, and kills plankton, marine snails and other small creatures that supply food for the rest of the marine ecosystem. Highly acidic water also kills fish eggs.

The result:

The most extensive survey of pH levels in the Pacific Ocean confirms what spot measurements have suggested: From Hawaii to Alaska, the upper reaches of the sea are becoming more acidic in concert with rising carbon dioxide in the atmosphere.

“The fact that we saw this very significant change over the last 15 years is a reminder of how mankind is affecting the oceans at an ever-increasing rate,” said report co-author Richard Feely, of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle.

The research teams measured acidity along 2,800 miles of ocean between Oahu and Kodiak in 1991, and returned in 2006 aboard a University of Washington research vessel, analyzing nearly 1,500 water samples over two months. To read more of the results, follow this link.

Other scientists warn the findings won’t be confined to the one area of the Pacific studied in the report.

“If you see these changes across an entire ocean basin, you can be assured it’s happening on a global scale in other ocean basins around the world,” said Robert Byrne, a marine chemist at the University of South Florida and lead author of an upcoming paper in Geophysical Research Letters.

— Rita Hibbard

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