A study from the Woods Hole Oceanographic Institute is warning that mollusks, especially oysters and mussels, are increasingly vulnerable to the acidification of the oceans caused by rising carbon dioxide emissions.

A news release from the institute  on Aug. 2 notes

As CO2 levels driven by fossil fuel use have increased in the atmosphere
since the Industrial Revolution, so has the amount of CO2 absorbed by
the world's oceans, leading to changes in the chemical make-up of
seawater. Known as ocean acidification, this decrease in pH creates a
corrosive environment for some marine organisms such as corals, marine
plankton, and shellfish that build carbonate shells or skeletons

.

The new study, which was published online July 7, 2011, by the journal Fish and Fisheries, assesses each country's vulnerability to decreases in mollusk harvests caused by ocean acidification.

It appears, that the higher latitudes, which would include the northwest coast, are, for the moment, at lower risk than tropical regions.

The news release goes on to say:

In order to assess each nation's vulnerability, researchers examined several dependence factors: current mollusk production, consumption and export; the percentage of the population that depends on mollusks for their protein; projected population growth; and current and future aquaculture capacity.

Using surface ocean chemistry forecasts from a coupled climate-ocean model, researchers also identified each nation's "transition decade," or when future ocean chemistry will distinctly differ from that of 2010, and current mollusk harvest levels cannot be guaranteed. These changes are expected to occur during the next 10 to 50 years, with lower latitude countries seeing impacts sooner. Higher latitude regions have more variability, and organisms there may be more tolerant to changing conditions.

The author of the study, Sarah Cooley, says, ""Mollusks are the clearest link we have at this point," Cooley said. "As ocean acidification responses of fin fish become more apparent, and as we learn more about the biological relationships between mollusks and other animals, then we can start zeroing in on how non-mollusk fisheries can also be affected."