How does rising atmospheric CO2 affect marine organisms?

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Reef Persistence Under Real-world Extremes of Ocean Acidification

Paper Reviewed
Enochs, I.C., Formel, N., Manzello, D., Morris, J., Mayfield, A.B., Boyd, A., Kolodziej, G., Adams, G. and Hendee, J. 2020. Coral persistence despite extreme periodic pH fluctuations at a volcanically acidified Caribbean reef. Coral Reefs

In the words of Enochs et al. (2020), "much of what we know about reef species responses to ocean acidification has come from laboratory experiments, which by design represent a simplification of environmental conditions and ecological interactions." Continuing, they add that "while these data are critical, incorporation of real-world complexity into ocean acidification research is necessary for understanding and predicting reef ecosystem responses." And thus the team of nine marine scientists went on to provide some of that real-world complexity by investigating the response of corals living near a volcanic CO2 vent at a Caribbean reef in Mayreau, St. Vincent and the Grenadines.

Results of their investigation revealed localized CO2 enrichment around the volcanic seep that amounted to frequent episodes of "extreme acidification with pH levels as low as 6.540 and undersaturation of aragonite." Surprisingly, Enochs et al. report that "despite localized CO2 enrichment and gas venting, the surrounding area has high hard and soft coral cover, as well as extensive carbonate frameworks." Such observations, in their words, "supports up-regulation of pH at the site of calcification" and further indicates "mechanisms of resilience to [the] extreme acidification stress." And that would suggest concerns over the future of these key marine organisms in response to so-called ocean acidification may well be over-blown.

Posted 4 May 2020