Paper Reviewed
Carey, N., Dupont, S. and Sigwart, J.D. 2016. Sea hare I (Mollusca: Gastropoda) can maintain shell calcification under extreme ocean acidification. The Biological Bulletin 231: 142-151.

Representing the United States, Sweden and the United Kingdom, Carey et al. (2016) describe how they "examined metabolic rate, shell morphometry, and calcification in the sea hare Aplysia punctata under short-term exposure (19 days) to an extreme ocean acidification scenario (pH 7.3, ~2800 µatm pCO2)," along with a group of sea hares maintained in the much milder conditions of pH 8.1 and ~344 µatm pCO2.

At the conclusion 19-day study, the studied specimens "were examined for metabolic rate via closed-chamber respirometry, followed by removal and examination of the shell under confocal microscopy," while "staining using calcein determined the amount of new calcification that occurred over 6 days at the end of the acclimation period." And what did the three researchers discover by so doing?

Carey et al. report that "Aplysia punctata showed a 30% reduction in metabolic rate under low pH," but they say that "calcification was not affected," noting that "this species is apparently able to maintain calcification rate even under extreme low pH, and even when under the energetic constraints of lower metabolism." And as a parting remark, therefore, they write that "the capacity for invertebrates to maintain calcification under suboptimal abiotic conditions with strong internal acid-base regulation may be more widespread than has been recognized to date."