How does rising atmospheric CO2 affect marine organisms?

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No Behavioral Impairment from Elevated pCO2 Observed in a Coral Reef Grouper

Paper Reviewed
Raby, G.D., Sundin, J., Jutfelt, F., Cooke, S.J. and Clark, T.D. 2018. Exposure to elevated carbon dioxide does not impair short-term swimming behavior or shelter-seeking in a predatory coral-reef fish. Journal of Fish Biology 93: 138-142.

Much remains to be learned about the potential impacts (or non-impacts) of so-called ocean acidification on marine life. In the present study, Raby et al. (2018) examined the behavioral response of adult bluespotted rockcod (Cephalopholis cyanostigma), a coral-reef grouper, to present-day (406 µatm) or predicted future (945 µatm) pCO2 conditions. The fish were acclimated to such conditions for a period of 8-9 days in a laboratory, after which they were released to the ocean at the water surface directly above a reef that was 5 meters below. At their release, the fish were filmed and several aspects of their behavior were examined for differences induced by the pCO2 treatment.

The results of the study, in the words of the authors, revealed that "no differences were detected between groups in any of the six measured variables, which included the time fish spent immobile after release, tail beat frequency during swimming and the time required to locate and enter the protective shelter of the reef." Consequently, Raby et al. conclude that the "basic functioning of vision, swimming and decision making that were required by fish to locate and enter shelter upon release from the surface were not affected by exposure to high CO2."

In commenting on these findings, or rather the lack thereof, the authors note that there are "a growing number of studies that have failed to detect any statistically significant behavioral changes in coral-reef fish acclimated to high CO2." And you can read about many of those studies that we have reviewed on our website here.

Posted 28 September 2018