Shellfish affected by corrosive ocean water

Mar 28, 2013

Bill Dewey of Shelton, Wash., and his colleagues have to watch water quality levels at their oyster hatchery to keep plumes of acidic water from affecting their harvest. / Scott Eklund/USA Today

OYSTER BAY, WASH. — The tide rolls out on a chilly March evening, and the oystermen roll in, steel rakes in hand, hip boots crunching on the gravel.

As they prepare to harvest shellfish, a danger lurks beyond the shore that will threaten clams, mussels, everything with a shell or that eats something with a shell. The entire food chain could be affected.

“Ocean acidification,” the shifting of the ocean’s water toward the acidic side of its chemical balance, has been driven by climate change and has brought corrosive seawater to the surface along the West Coast and the inlets of Puget Sound, the center of the $111 million shellfish industry.

affecting lives.

The acidification taking place here guarantees the same for the rest of the world’s oceans in the years ahead. This isn’t the kind of acid that burns holes in chemist’s shirt sleeves. But since the start of the industrial revolution, the world’s oceans have grown nearly 30 percent more acidic, according to a 2009 Scientific Committee on Oceanic Resources report. Why? Climate change, where heat-trapping carbon dioxide emitted into the air by burning coal, oil and other fossil fuels ends up as excess carbonic acid absorbed into the ocean.

“As fresh as they get, you could eat one now,” said Bill Dewey of Taylor Shellfish in Shelton, Wash., shucking an oyster open, mud running from its shell to reveal the meat within.

The acid process

Because of ocean chemistry, water three times more acidic resides at greater ocean depths. When conditions are right, strong winds blowing over ocean water along steep coasts generate “upwelling” of these deep waters. The results bring this more corrosive seawater to places such as Puget Sound, a foreshadowing of how the oceans will look in a few decades.

“We are able to see the effects of ocean acidification,” said oceanographer Richard Feely of the National Oceanic and Atmospheric Administration. He first charted upwelling of deeper, corrosive ocean water on the surface of the Pacific Ocean along the West Coast on a 2007 expedition.

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