The pteropod Limacina helicina is a tiny shelled marine snail that swims using a pair of converted feet as wings. It has earned the name “sea butterfly” because of its elegant swimming style, and “potato chip of the sea” because of its importance as a food source for so many Arctic marine species from zooplankton to seabirds to fish. Limacina helicina starts life as a male and becomes female when it reaches a larger size. It captures its prey by casting a web of mucus that traps tiny plankton.
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. 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. The decline of these key organisms would result in dramatic impacts for the entire marine food web.