The first suspects were bacteria.
Something was killing the microscopic oyster larvae at the hatcheries in Washington's Dabob Bay and in Oregon's Netarts Bay in recent years. The tiny oyster shells were crumbling faster than they could grow back, says Bill Dewey, public policy director for Taylor Shellfish Farms, which harvests geoducks, oysters, and other shellfish around Puget Sound. And soon, hatchery experts realized increasing ocean acidification was the true culprit. But what exactly that means, is yet to be determined.
"Ocean debasification is a bit awkward and not scientifically precise," says Jan Newton, a senior principal oceanographer at the University of Washington.
Think back to high school chemistry and "pH," which measures the acidity or alkalinity of a fluid on a 14-point scale. The lower the number, the more acidic something is. Distilled water is a seven and is considered "neutral." Sea water's pH is normally 8.1 to 8.2 on the alkaline side, where as black coffee's pH is five on the acidic side. Orange juice's pH is three. Battery acid is in the neighborhood of one.
Well, shellfish survive within a narrow pH spectrum. Taylor Shellfish's oyster hatchery -- located in the Hood Canal fjord jutting out from Puget Sound -- lets sea water in at two locations, one that's 15 feet deep and one that's 100 feet deep. One day last week, the pH of the water at 15 feet was 8.4, while the water's pH at 100 feet deep was 7.5, meaning the hatchery has to be especially careful about where its water comes from.
Scientists around the world have been studying ocean acidification in labs for decades, and many have been tracking shellfish hatcheries along the Oregon and Washington coasts. But the deaths of these baby oysters in the Pacific Northwest are the first confirmed cases of increasing ocean acidification killing aquatic creatures in the real world. And, in an area where shellfish harvesting is a $270 million-a-year industry that employs about 3,200 people, this is a big cause for concern.