There are about 200 oxygen depleted regions, or dead zones, in the world’s oceans. They occur when fertilizers and manure in runoff reach the sea, fueling algae that eats up all the oxygen. 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 dead zone in the Northwest.