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Effects of CO2-Induced Ocean Acidification on a Common Copepod

Paper Reviewed
Cao, Z., Mu, F., Wei, X. and Sun, Y. 2015. Influence of CO2-induced seawater acidification on the development and lifetime reproduction of Tigriopus japonicus Mori, 1938. Journal of Natural History 49: 2813-2826.

Concerned about the potential effects of CO2-induced ocean acidification on the world's marine animal life, Cao et al. (2015) exposed some harpacticoid copepods (Tigriopus japonicas Mori, 1938) to "seawater equilibrated with CO2 and air to reach pH 8.0 (control), 7.7 (the predicted ocean pH by 2100), 7.3 (the predicted ocean pH by 2300) and 6.5 (an extreme condition relevant to industrial acid waste discharge or leakage from CO2 seabed storage)." And what did they find by so doing?

The three Chinese scientists report that (1) "the survival rate of larvae in the CO2 treatments was not significantly different from the control," that (2) "no adult female mortality was observed at any of the pH levels over the duration of the reproduction experiment," that (3,4) "both the developmental and reproductive parameters were only significantly different from the controls at pH 7.3 and pH 6.5," demonstrating that (5) "T. japonicas will be able to tolerate the levels of ocean acidification predicted for the rest of this century."

Further evidence for this conclusion is provided by the fact that (6) T. japonicus, as Cao et al. report, "can tolerate drastic variations in the physicochemical environment of high-tidal rock pools," which has also been demonstrated to be the case by Morris and Taylor (1983) and the study of Daniel and Boyden (1975), who found that "the diurnal variation of pH in tidal pools ranged from 7.2 to 9.5."

In one final remark, the Chinese scientists also note that although "Pedersen et al. (2014) observed a retarded development rate among parental-generation copepods raised at 2080 ppm CO2," there was a "normalization of the development rate among their F1-generation offspring when raised under the same conditions, suggesting that copepods could have the potential to adapt to future ocean acidification conditions."

Daniel, M.J. and Boyden, C.R. 1975. Diurnal variations in physico-chemical conditions within intertidal rock pools. Field Studies 4: 161-176.

Morris, S. and Taylor, A.C. 1983. Diurnal and seasonal variation in physicochemical conditions within intertidal rock pools. Estuarine, Coastal and Shelf Science 17: 339-355.

Pedersen, S.A., Hakedal, O.J., Salaberria, I., Tagliati, A., Gustavson, L.M., Jenssen, B.M., Olsen, A.J. and Altin, D. 2014. Multigenerational exposure to ocean acidification during food limitation reveals consequences for copepod scope for growth and vital rates. Environmental Science and Technology 48: 12,275-12,284.

Posted 31 March 2016