Where scientists previously found a sea bottom abounding with life, two years ago they discovered the rotting carcasses of crabs, starfish and sea worms, swooshing from side to side in the current. Most fish had fled -- and those that didn't or couldn't joined the deathfest on the sea floor. Extraordinarily low oxygen levels were to blame -- swept up from the deep ocean into normally productive waters just off the Pacific Northwest coast by uncharacteristically strong winds.
On Thursday scientists announced they had documented that low oxygen levels that killed the sea life in 2006 were the lowest in a half-century -- and that for the first time, parts of the ocean off our coast were measured with zero oxygen in the water; 2007 looked only a bit better. Strong winds and low oxygen levels have persisted for eight summers now, leading scientists to conclude that the ocean may be "poised for significant reorganization"-- their way of saying an ecosystem gone awry.
It looks like the Pacific has reached a "tipping point," a threshold where low-oxygen levels are becoming the rule, researchers said. And while scientists can't prove it's caused by a changing climate, that's consistent with what is predicted by computer projections built to anticipate global warming. "The real thing in the back of our minds is: Is this the first signs of what global warming might be like?" said Bill Peterson, a federal scientist and co-author of the research published in the journal Science. But because it's not conclusive proof, he said, "We tried not to go there too much."
Whatever the cause, it's worrisome, researchers said, because shallow, productive ocean areas like those off the Northwest coast occupy just 1 percent of the globe's oceans -- yet produce 20 percent of the fish we eat.
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http://seattlepi.nwsource.com/local/351374_oceans15.html
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