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The Response of Two Branching Corals to Ocean Acidification

Paper Reviewed
Sekizawa, A., Uechi, H., Iguchi, A., Nakamura, T., Kumagai, N.H., Suzuki, A., Sakai, K. and Nojiri, Y. 2017. Intraspecific variations in responses to ocean acidification in two branching coral species. Marine Pollution Bulletin 122: 282-287.

Writing as background for their work, Sekizawa et al. (2017) state that "controversy remains over whether [marine calcifying organisms] could cope with ocean acidification within a range of phenotypic plasticity and/or adapt to future acidifying ocean." Therefore, it became their objective to conduct a laboratory experiment on two common branching corals (Montipora digitara and Porites cylindrical) to see if there were any intraspecific variations in their responses to reductions in seawater pH.

Their work was conducted in a controlled-environment laboratory where they grew coral nubbins collected from twelve colonies of each branching coral under either control (400 µatm) or high (900 µatm) seawater pCO2 for 28 days. In describing their findings, Sekizawa et al. say they "succeeded in detecting clear intraspecific variations in calcification responses to acidified seawater, suggesting that corals might be able to cope with future acidifying ocean within their phenotypic plasticities (e.g., epigenetics; Putnam and Gates, 2015) and/or by altering genotypic composition within populations if the intraspecific variations are tightly related to genotypes." And it would thus appear that predictions of widespread coral demise in response to ocean acidification are both premature and likely overblown.

Putnam, H.M. and Gates, R.D. 2015. Preconditioning in the reef-building coral Pocillopora damicornis and the potential for trans-generational acclimatization in coral larvae under future climate change conditions. Journal of Experimental Biology 218: 2365-2372.

Posted 14 December 2017