NSF launches oceanic zest test

Buoy to monitor CO2 absorption

The first ever system designed specifically to measure the acid levels in the oceans was launched this week. The project, funded by the US's National Science Foundation (NSF), aims to determine how much CO2 the Pacific Ocean absorbs each year.

Steven Emerson of the University of Washington, the project's lead scientist, commented: "This is the first system specifically designed to monitor ocean acidification. The instruments will measure the air-sea exchange of carbon dioxide, oxygen, and nitrogen gas in addition to the pH, a measure of ocean acidity, of the surface waters."

A ten-foot diameter buoy carrying all the instruments is now anchored in water nearly 5,000 metres deep in the Gulf of Alaska. According to the NSF, as soon as it hit water, the buoy started transmitting data via satellite.

Seas become more acidic as they absorb carbon dioxide. The interest in oceanic pH lies partly in the fact that an increase in their acidity, or fall in pH, suggests an increase in the levels of these gases in the atmosphere. But the pH of the oceans is also vital to the health of marine life, and scientists see acidification as a growing threat to the health of our marine systems.

In 2005, the Royal Society (RS) reported that evidence indicated the overall pH of the oceans' surface had fallen by 0.1 units over the last 200 years as they have absorbed around half of all man-made CO2 emissions. The pH could fall a further 0.5 units by 2100, the RS said.

The phenomenon is also essentially irreversible in our lifetimes. The Royal Society says it will take tens of thousands of years for the oceans to return to their pre-industrial state.

Fred Lipschultz, programme director in NSF's division of ocean sciences, said: "Information from this buoy will lead to a better understanding of ocean acidification by helping scientists determine exactly how physical and biological processes affect carbon dioxide in the north Pacific Ocean."

Last month, scientists at the British Antarctic Survey voiced concerns that the southern ocean is reaching saturation point, and reported a recent release of stored CO2. ®

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