Pacific Ocean ecosystems hurt by global warming

Baby shellfish off the coasts of Oregon and Washington may be global warming's canary in the coalmine.   Hatchery production declined this year by 80% due to ocean acidification, which occurs when the ocean absorbs billions of tons of carbon from the atmosphere.  Marine chemists have been studying changes in the ocean´s acid levels for decades but it´s only recently that their findings are pointing to serious changes in marine ecosystems.  Martha Baskin has the story.