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Oceans Turn More Acidic Than Last 800,000 Years

The question is not whether acidification is happening, but how bad it will get



NASA EARTH OBSERVATORY

SAN DIEGO—For more than 30 years, scientists have understood the link between rising carbon dioxide emissions and climate change. But it wasn't until the middle of the last decade that they realized CO2 emissions could alter the chemistry of the world's oceans to devastating effect.

Now they're making up for lost time, researchers said this weekend at the annual meeting of the American Association for the Advancement of Science.

Richard Feely, an oceanographer with the National Oceanic and Atmospheric Administration, said his agency is preparing to release its first ocean acidification research plan.

"It's going to be delivered to headquarters next month," he said. "Our plan includes coastal observations, technology development, remote sensing using satellites, an observational network with moorings to measure CO2, [and] physiological research on how various organisms respond to changes."

And the National Academy of Sciences is also expected to weigh in. An NAS committee will release a congressionally mandated study by the end of next month that will address everything from scientific questions about how ocean acidification will affect marine life and ocean-dependent industries to recommendations for a national acidification research program.

Victoria Fabry, a visiting research scientist at the Scripps Institution of Oceanography and a member of the NAS panel, said researchers can already detect and measure CO2-driven changes in ocean chemistry.

Feely, for example, led a 2007 NOAA expedition that found corrosive waters off North America's Pacific coast at levels not expected until 2050.

Now, Fabry said, the question is not whether acidification is happening, but how bad it will get -- which depends on future CO2 emissions.

"Today, the atmospheric CO2 concentration is about 388 parts per million," she said. "This is the highest that it's ever been in the past 800,000 years -- as far back as the record goes right now. And there are concerns about where we're headed."

A 30% rise since the Industrial Revolution

Since the beginning of the Industrial Revolution, the oceans have absorbed about a third of human-caused carbon dioxide emissions. That has resulted in water 30 percent more acidic than it was before factories, cars, planes and other fossil fuel-burning machines became widespread.

By the end of the century, if CO2 emissions grow at the current trajectory, the world's oceans could become 150 percent more acidic. That doesn't bode well for sea creatures like oysters, corals and plankton that grow hard shells made of a chalky mineral called calcium carbonate. If ocean water becomes too acidic, it can begin dissolving those shells, sometimes faster than creatures can rebuild them. It's a development scientists believe could ripple up the food chain.



But one piece of good news, according to Feely, is the rapid development of tools to monitor acidification.

They include a new instrument, developed by researchers at the University of South Florida, that can be placed on commercial vessels to collect measurements of pH and other indicators of ocean carbon levels as the ships traverse the seas.

A new West Coast ocean acidification observing system is also planned, Feely said, with several observation sites manned by different research institutions, such as the Monterey Bay Aquarium Research Institute.

Ed Miles, a professor of marine studies and public affairs at the University of Washington, said the prospect of a coordinated federal ocean acidification research program is welcome news, especially given the conditions Feely observed off the California coast in 2008.

"We had better invest in expanding our observing capacity, because what happened in the open and coastal ocean was a major surprise," Miles said. "We can't afford to be taken by surprise of that sort."

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