Tuesday, February 16, 2010

Upper half mile of ocean increasingly acidic

The scary underbelly of the whole climate change scenario is that the oceans are being changed fundamentally.

As carbon dioxide builds up in the air, some of it mixes with water and becomes acid. The increasing acidity of the oceans has been reported before, but the latest data, representing the first broad survey of the Pacific basin, is compelling.

Direct observations of basin-wide acidification of the North Pacific Ocean” is reported in the journal Geophysical Research Letters by Robert H. Byrne and Xuewu Liu of the College of Marine Science, University of South Florida, Sabine Mecking of the Applied Physics Laboratory, University of Washington. Richard A. Feely, of the Pacific Marine Environmental Laboratory, NOAA.

They took 2,100 samples, from the surface to the ocean floor, during cruises between O'ahu and Kodiak, Alaska—obtaining a unique cross-sectional slice of the Pacific Ocean. Cruises took place in 1991 and again in 2006.

They found that in those 15 years, there had been a marked increase in acidity in the upper half-mile of the ocean, which in some places is more than 3 miles deep.

Previous studies have found similar results in single locations. What this study does is “confirm on a large scale what has been observed at three time-series points in the north Atlantic and Pacific — significant upper ocean acidification, roughly keeping pace with rising atmospheric carbon dioxide.

“It appears that future acidification of the ocean's mixed layer can be expected to occur at rates that closely mirror changes in atmospheric CO2...

“If atmospheric CO2 continues to rise at an accelerating rate, ocean pH can be expected to fall at an accelerating rate.”

What does that mean? It most likely means bad news for corals, shellfish, plankton and all kinds of other marine life that depend on no rapid changes in the oceans' acidity-alkalinity balance.

And it is perhaps the most unassailable argument for reducing our production of carbon dioxide.

© Jan TenBruggencate 2010

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