A sweeping 15-year study of pH levels in the Pacific Ocean confirmed that upper reaches of the sea are becoming increasingly more acidic. One-sixth of the nation's oysters come from Willapa Bay, epicenter of the West's $111 million oyster industry.  STEVE RINGMAN / THE SEATTLE TIMES

By Sandi Doughton, Seattle Times science reporter The most extensive survey of pH levels in the Pacific Ocean confirms what spot measurements have suggested: From Hawaii to Alaska, the upper reaches of the sea are becoming more acidic in concert with rising carbon dioxide in the atmosphere. “If you see these changes across an entire ocean basin, you can be assured it’s happening on a global scale in other ocean basins around the world,” said Robert Byrne, a marine chemist at the University of South Florida and lead author of an upcoming paper in Geophysical Research Letters. Ocean acidification is a threat to shelled creatures and other marine life, and is a leading suspect in the ongoing crash of Pacific oyster populations in Washington. Byrne collaborated with Seattle scientists on the survey, which was 15 years in the making. The team first measured acidity along the 2,800-mile sweep of ocean between Oahu and Kodiak in 1991. They returned in 2006 aboard the University of Washington research vessel Thomas G. Thompson, working around the clock in shifts to collect and analyze nearly 1,500 water samples over two months. Washington’s troubled shellfish industry It’s the first time measurements have been taken across such a wide area, said co-author Richard Feely, of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle. “The fact that we saw this very significant change over the last 15 years is a reminder of how mankind is affecting the oceans at an ever-increasing rate,” Feely said.  … The result can be an environment where shells dissolve, destroying plankton, marine snails and other small creatures that sustain the rest of the marine food web. Acidified water also can kill fish eggs and larvae. …

Pacific’s rising acid levels threatening marine life