There are about 200 oxygen depleted regions, or dead zones, in the world's oceans. They occur when nutrients from run-off ? fertilizers and manure to name a few ? make it into major water bodies and cause oxygen depletion. But a dead zone off the coast of the Pacific Northwest has scientists looking at a different culprit ? climate change. Host Steve Curwood turns to Professor Jack Barth of Oregon State University to learn more about what might be behind the Northwest dead zone.