Ocean Acidification is also known as CO2's other pending disaster. As increasing CO2 from the atmosphere enters the oceans it causes a lowering of pH...normal is 8.1. Some areas in Puget Sound have been measured as low as 7.4. As the ocean becomes more acidic it reduces the ability of organisms that produce calcium carbonate shells and skeletons to produce those parts. In planktonic organisms and larval stages more acidic water may kill the organism.
On Washington's Willapa Bay and other areas another problem is the increase in upwelling (a normal spring/summer process) brings oxygen depleted, gas saturated, more acidic cold water into shallow bays where oyster reefs are located, and into oyster hatcheries. This water interferes with the development of larval oysters. This is a major problem for oyster growers, not to mention the oysters. A lowering of ocean pH will only add to this problem. To read more on the subject check out: