Pteropods are among the marine creatures most vulnerable to ocean acidification. Ocean acidification lowers the availability of the mineral aragonite that pteropods use to form their shell, hindering this snail from building its protective armor. Scientists have found that Limacina helicina individuals that are exposed to the acidic ocean conditions expected at the end of the century are significantly less able to build their shells. [1] Acidic ocean conditions may be lethal for Limacina helicina in parts of the Arctic Ocean in the next few decades and across the Arctic Ocean before mid-century if current emission trends continue. [2] The decline of these key organisms would result in dramatic impacts for the entire marine food web.