How does rising atmospheric CO2 affect marine organisms?

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Effects of Elevated CO2 on Growth Rates of Three Coccolithophores
Fiorini, S., Middelburg, J.J. and Gattuso, J.-P. 2011. Testing the effects of elevated pCO2 on coccolithophores (Prymnesiophyceae): Comparison between haploid and diploid life stages. Journal of Phycology 47: 1281-1291.

What was done
The growth rates of three coccolithophores (Emiliania huxleyi, Calcidiscus leptoporus and Syracosphaera pulchra) were measured in laboratory batch cultures in both their haploid and diploid life stages, while they were growing in filtered seawater maintained in equilibrium with air containing either 400 or 760 ppm CO2.

What was learned
The three researchers report that for all three species, "the growth rate was consistently higher at elevated pCO2," but that "the response of other processes varied among species." Calcification rates of C. leptoporus and of S. pulchra did not change at elevated pCO2, for example, whereas this important process was increased in the case of E. huxleyi. In addition, they found that these CO2-induced impacts were most pronounced in the haploid stage.

What it means
In a very simple and straightforward conclusion to their study, Fiorini et al. state that these effects "must be taken into account when predicting the fate of coccolithophores in the future ocean." And when they are taken into account, we would add, we do not see the devastating future that the world's climate alarmists generally portray to the public.

In the words of the European scientists, "the phenotypic and physiological differences of the two life stages allow each species to use two different niches to exploit a wider range of ecological conditions (Cros et al., 2000), to limit the competition in the utilization of resources (food, light) inside the species and to rapidly escape negative selection pressures exerted on one stage such as grazing, parasitic attack, viral infections (Frada et al., 2008), or abrupt environmental changes (Noel et al., 2004)." And in this way, as they continue, "the survival of a species is ensured by one life stage when the environmental conditions do not favor the development of the other life stage (Houdan et al., 2005)."

Cros, L., Kleijne, A., Zeltner, A., Billard, C. and Young, J.R. 2000. New examples of holococcolith-heterococcolith combination coccosheres and their implications for coccolithophorid biology. Marine Micropaleontology 39: 1-34.

Frada, M., Probert, I., Allen, M.J., Wilson, W.H. and De Vargas, C. 2008. The "Cheshire Cat" escape strategy of the coccolithophore Emiliania huxleyi in response to viral infection. Proceedings of the National Academy of Sciences USA 105: 15,944-15,949.

Houdan, A., Probert, I., Van Lenning, K. and Lefebvre, S. 2005. Comparison of photosynthetic responses in diploid and haploid life-cycle phases of Emiliania huxleyi (Prymnesiophyceae). Marine Ecology Progress Series 292: 139-146.

Noel, M.-H., Kawachi, K. and Inouye, I. 2004. Induced dimorphic life cycle of a coccolithophorid, Calyptrosphaera sphaeroidea (Prymnesiophyceae, Haptophyta). Journal of Phycology 40: 112-129.

Reviewed 21 March 2012