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The robustness of the Antarctic scallop to ocean acidification

02 Jun 2021 | Science Notes

From CO2Science: Climate alarmists consider the Arctic and Antarctic marine environments to be among the most threatened by so-called ocean acidification, where they anticipate the potential extinction of a multitude of marine species whose calcium carbonate skeletons, they claim, will dissolve away as increasing amounts of atmospheric CO2 makes its way into the surface waters of these environments in the years and decades ahead. But is this assumption correct?

Paper reviewed: Dell’Acqua, O., Trebala, M., Chiantore, M. and Hannula, S.-P. 2019. Robustness of Adamussium colbecki shell to ocean acidification in a short-term exposure. Marine Environmental Research 149: 90-99.

In exploring this hypothesis, Dell’Acqua et al. (2019) studied the response of a key benthic species, the Antarctic scallop (Adamussium colbecki), to two difference seawater pH regimes over a period of 37 days. Their experiment was conducted under controlled-environment conditions at the Italian Mario Zucchelli research station (Terra Nova Bay, Ross Sea) during the austral summer of 2014/15. Adult scallop specimens were collected from Tethys Bay, close to the research station, and then acclimated for two weeks in seawater tanks. Following the acclimation period, the scallops were exposed to either control (8.12) or reduced (7.6) pH seawater for 37 days. Various shell mechanical properties were examined at the end of the experiment, including scanning electron microscopy, nanoindentation and Vickers indentation, to determine the impact of ocean acidification on the robustness of this Antarctic scallop’s shell.

The results of the analyses were definitive; in the words of Dell’Acqua et al. “no effect of pH could be detected either in crystal deposition or in the mechanical properties.” Consequently, the authors conclude that “A. colbecki shell structure and mechanical properties are resistant to a short-term OA exposure, both at the micro- and at the nanoscale, suggesting potential robustness of this benthic key species in light of future calcium carbonate undersaturation.” With respect to the potential mechanism behind such shell robustness, the four researchers write that it “may reflect either a lower energy requirement for shell repair and maintenance, or the ability to reallocate energies among body functions/organs, thanks to a preadaptation history.” Whatever the case may be, one thing is certain: this shell of this species is far more robust to ocean acidification that climate alarmists are wont to believe/accept. And, taken together, these findings are very encouraging for the future of the Antarctic scallop and other marine life dependent upon it.

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