[MARINE_BIOLOGY_INTERNATIONAL] Ocean acidification emerges as new climate threat

Homer, AK — Kris Holderied, who directs the National Oceanic and Atmospheric Administration's Kasitsna Bay Laboratory, says the ocean's increasing acidity is "the reason fishermen stop me in the grocery store."

"They say, `You're with the NOAA lab, what are you doing on ocean acidification?' " Holderied said. "This is a coastal town that depends on this ocean, and this bay."

Ocean acidification threatens U.S. fisheries: Human-generated carbon emissions are making the ocean more acidic, which has become a cause for concern to the fishing industry and scientists.

This town in southwestern Alaska dubs itself the Halibut Fishing Capital of the World. But worries about the changing chemical balance of the ocean and its impact on the fish has made an arcane scientific buzzword common parlance here, along with the phrase "corrosive waters."

In the past five years, the fact that human-generated carbon emissions are making the ocean more acidic has become an urgent cause of concern to the fishing industry and scientists.

The ocean absorbs about 30 percent of the carbon dioxide we put in the air through fossil fuel burning, and this triggers a chemical reaction that produces hydrogen, thereby lowering the water's pH.

The sea today is 30 percent more acidic than pre-industrial levels, which is creating corrosive water that is washing over America's coasts. At the current rate of global worldwide carbon emissions, the ocean's acidity could double by 2100.

What impact it is having on marine life, how this might vary by geography and species, and what can be done about it if humans do not cut their carbon output significantly are some of the difficult questions scientists and policymakers are seeking to answer.

The decline in pH will likely disrupt the food web in many ways. It is making it harder for some animals, such as tiny pteropods and corals, to form their shells out of calcium carbonate, while other creatures whose blood chemistry is altered become disoriented and lose their ability to evade predators.

To study what is happening off the West Coast, Gretchen Hofmann, a professor of marine biology at the University of California at Santa Barbara, has recruited everyone from sea-urchin divers to Bureau of Ocean Energy Management, Regulation and Enforcement officials.

She calls it "an all-hands-on-deck moment in our country, and it's happening before our eyes."

The NOAA has started tracking changes in the ocean's pH over time in eight coastal and coral reef ecosystems, ranging from the Gulf of Maine to coastal Hawaii, and is evaluating its impact on more than two dozen commercially important species, such as red king crab, summer flounder and black sea bass.

"One of the primary questions is how is the chemistry of the water changing and how variable is that change across the water we're responsible for, which is a lot of coastline," said Libby Jewett, director of the program.

Federal and state authorities are searching for ways to cope with a problem whose obvious solution — slashing global carbon emissions — remains elusive. A blue-ribbon panel established by outgoing Washington Gov. Chris Gregoire (D), which will issue its recommendations in November, is examining local contributors such as agricultural runoff. Federal officials and scientists, meanwhile, are trying to determine which species may be able to adapt to more acidic seas and explore what other protections could bolster fish populations under pressure.