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Predominance of heavily calcified coccolithophores at low CaCO3 saturation during winter in the Bay of Biscay

Smith, H.E.K., Tyrrell, T., Charalampopoulou, A., Dumousseaud, C., Legge, O.J., Birchenough, S., Pettit, LR., Garley, R., Hartman, S.E., Hartman, M.C., Sagoo, N., Daniels, C.J., Achterberg, E.P. and Hydes, D.J. (2012) Predominance of heavily calcified coccolithophores at low CaCO3 saturation during winter in the Bay of Biscay Proceedings of the National Academy of Sciences, 109, (23), pp. 8845-8849. (doi:10.1073/pnas.1117508109).

Record type: Article


calcifiers, their possible susceptibility to ocean acidification is of major concern. Laboratory studies at enhanced pCO2 levels have produced divergent results without overall consensus. However, it has been predicted from these studies that, although calcification may not be depressed in all species, acidification will produce “a transition in dominance from more to less heavily calcified coccolithophores” [Ridgwell A, et al., (2009) Biogeosciences 6:2611–2623]. A recent observational study [Beaufort L, et al., (2011) Nature 476:80–83] also suggested that coccolithophores are less calcified in more acidic conditions. We present the results of a large observational study of coccolithophore morphology in the Bay of Biscay. Samples were collected once a month for over a year, along a 1,000-km-long transect. Our data clearly show that there is a pronounced seasonality in the morphotypes of Emiliania huxleyi, the most abundant coccolithophore species. Whereas pH and CaCO3 saturation are lowest in winter, the E. huxleyi population shifts from <10% (summer) to >90% (winter) of the heavily calcified form. However, it is unlikely that the shifts in carbonate chemistry alone caused the morphotype shift. Our finding that the most heavily calcified morphotype dominates when conditions are most acidic is contrary to the earlier predictions and raises further questions about the fate of coccolithophores in a high-CO2 world.

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Published date: 21 May 2012
Keywords: phytoplankton, north atlantic, climate change
Organisations: Marine Biogeochemistry, Ocean Biochemistry & Ecosystems


Local EPrints ID: 340765
ISSN: 0027-8424
PURE UUID: 04e65a94-a8f7-44cc-be46-c4a9a004f223
ORCID for T. Tyrrell: ORCID iD

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Date deposited: 02 Jul 2012 14:12
Last modified: 18 Jul 2017 05:41

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Author: H.E.K. Smith
Author: T. Tyrrell ORCID iD
Author: A. Charalampopoulou
Author: C. Dumousseaud
Author: O.J. Legge
Author: S. Birchenough
Author: LR. Pettit
Author: R. Garley
Author: S.E. Hartman
Author: M.C. Hartman
Author: N. Sagoo
Author: C.J. Daniels
Author: E.P. Achterberg
Author: D.J. Hydes

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