How does rising atmospheric CO2 affect marine organisms?

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Some Sea Life Does Not Adapt to OA; It Makes OA Adapt to Them

Paper Reviewed
Hendriks, I.E., Duarte, C.M., Olsen, Y.S., Steckbauer, A., Ramajo, L., Moore, T.S., Trotter, J.A. and McCulloch, M. 2015. Biological mechanisms supporting adaptation to ocean acidification in coastal ecosystems. Estuarine, Coastal and Shelf Science 152: A1-A8.

In an Invited Feature in Estuarine, Coastal and Shelf Science, Hendriks et al. (2015) -- in the words of the journal's Editor -- "make the case that acidification forced by increased atmospheric carbon dioxide may not uniformly affect all marine environments," based on "a series of arguments that pH regulation in coastal waters may be differentially affected not only by carbon dioxide diffusion from the atmosphere, but also by large and heterogeneous reactant inputs from altered watershed land covers, as well as by the rather more abundant and biologically active assemblages of coastal organisms."

As the eight researchers themselves describe it, based on a systematic review of the pertinent scientific literature (some 91 individual papers), "organisms influence pH at a patch scale where community metabolic effects and hydrodynamic processes interact to produce broad ranges in pH, (~0.3-0.5 units) over daily cycles and spatial scales (mm to m) particularly in shallow vegetated habitats and coral reefs where both respiration and photosynthetic activity are intense," while adding that "on the scale of individual organisms, small-scale processes including changes at the Diffusive Boundary Layer (DBL), interactions with symbionts, and changes to the specific calcification environment, induce additional changes in excess of 0.5 pH units."

"In these highly variable pH environments," as they describe them, they report that "calcifying organisms have developed the capacity to alter the pH of their calcifying environment, or specifically within critical tissues where calcification occurs, thus achieving a homeostasis." And they conclude that "this capacity to control the conditions for calcification at the organism scale may therefore buffer the full impacts of ocean acidification on an organism scale," adding that "in some areas, calcifiers may potentially benefit from changes to ambient seawater pH," particularly "where photosynthetic organisms draw down CO2."

Posted 25 May 2015