Grist has an excellent piece (originally published on OnEarth) exploring the reasons behind a sudden crash in oyster populations, with the complexity of the culprit -- ocean acidification.
"I'm afraid the ocean will be dead long before we have to worry about the other implications of global warming," Barton says quietly. "I didn't believe any of this stuff three years ago. I was always skeptical about our global models ... But ocean acidification is pretty cut and dried for me now. You see it every day. You can't escape it."