Man-made carbon dioxide making oceans more acidic, study finds

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Oceans worldwide are turning increasingly acidic as they absorb more carbon from the atmosphere, which could have negative effects on many forms of marine life at the base of the oceanic food chain, including plankton, coral and large mollusks such as oysters, a National Research Council study has found.

Oceans are an important part of the planet’s carbon cycle, and hold the largest active pool of carbon near the surface of the Earth. They absorb about a third of man-made carbon dioxide from the atmosphere, eventually converting it into carbonic acid and carbonic ions.

The study found that the equilibrium of this cycle has been upset, lowering the Ph of the ocean about .1 of a unit since the beginning of the industrial revolution -- a rate of change not seen in hundreds of thousands of years. The study predicts more striking changes by the century’s end.

Little is known about the long-term effects of a more acidic ocean, but studies have shown acidification affects many biological processes, including photosynthesis, nutrient uptake, growth and reproduction. The study predicts shifts in ecosystems, with some species winning and others losing. The overall consequences remain unknown.

-- Geoff Mohan