Then they noticed the water's pH — the scale measuring acidity and alkalinity — sometimes dropped below normal, becoming more acidic.
Seawater typically is slightly alkaline, but when oceans absorb carbon dioxide from the atmosphere — as they have by the hundreds of billions of tons since the Industrial Revolution — they become more corrosive.
Climate modelers predicted greenhouse gases would make marine waters more acidic by century's end. They expected to notice it first in deep water, some of which hasn't circulated to the surface in 1,500 years and has therefore accumulated more atmospheric carbon dioxide. And deep waters already run higher in carbon dioxide because dying plants, animals and fish sink and decay.
But two years ago, oceanographers Richard Feely and Chris Sabine, both with the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, found more acidified waters already reaching the surface.
The north winds that blow off Washington's coast push marine surface waters off shore. Those waters are replaced by the icy-cold, more corrosive seawater welling up from hundreds of meters below.
Throughout 2008, researchers at Oregon's Whiskey Creek Shellfish Hatchery noticed a trend: Their die-offs tended to come after north winds pushed those very same deep waters into the pipes that feed the hatchery.
"There seems to be a strong correlation," Feely said.
Ripple effects for fish
In a sense, that's exactly what scientists expected — just not so soon.
Corrosive waters can dissolve clam shells, eat away at corals and kill fish eggs. Already, scientists have taken pteropods, tiny marine snails that swim in the open ocean, from the Gulf of Alaska and exposed them to slightly acidified marine water in a laboratory. Their protective shells immediately dissolved.
Those creatures make up 60 percent of the food for Alaska's juvenile pink salmon. Similar creatures support many of the major fish species in Alaska's North Pacific, which in turn supports the billion-dollar Seattle-based industry that provides half the nation's catch of fish.
"The fish we depend on — salmon and pollock and herring — when they're in the first year of their life, they all depend on shellfish for survival," Feely said. "Early models suggest a 10 percent loss in pteropods can cause a 20 percent loss in weight of a fish."
Just last month, Smithsonian scientists published a paper suggesting that in the next century more acidified oceans will threaten the world's shellfish. Oyster larvae, they pointed out, are particularly susceptible. Their early shells are made from an easily eroded form of calcium carbonate.
Researchers believe that might be part of what's already happening on the Northwest coast. If oyster larvae are swimming in marine waters — whether pumped from the sea into a hatchery or in the bay — as deep, acidified water is pushed toward shore, "that could be a problem," said Simon Alin, a NOAA scientist who works with Sabine and Feely.
In addition, Vibrio tubiashii thrives in this more corrosive environment. "It becomes the dominant pathogen," Feely said.
Still, it's too soon to say for certain if these issues are localized or part of a broader phenomenon. The hatchery is not far from a low-oxygen dead zone off the Oregon coast. There also isn't sophisticated enough equipment in place to get precise pH readings.
But it all suggests significant ocean changes are coming fast, if they're not here already.
"We're not saying we're killing all life in the ocean," Sabine said. "There will be winners and losers. But this is not something that's off in the future. This is not something for our children's children. It's happening now."
Asking for help
Already the oyster industry is seeing job losses and other effects. In the last year, Taylor spent $500,000 just trying to get oysters to attach to shells in a secondary hatchery, said Willapa Division Manager Eric Hall.
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