Oceans are not acidic. That's propaganda. What has happened is that the amount of hydrogen ions has increased slightly. The water, however, remains firmly on the alkaline side of the pH chart. The term "ocean acidification" is a term used to engender fear. This is not to say that there was a period when emissions from power plants did cause acidification of some lakes in the northeastern U.S. So when they say "ocean acidification," put your hand on your wallet.