Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 9, 4155-4167, 2012
© Author(s) 2012. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
30 Oct 2012
Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta)
M. N. Müller1,4,5, L. Beaufort2, O. Bernard3, M. L. Pedrotti4,5, A. Talec4,5, and A. Sciandra4,5 1Institute for Marine and Antarctic Studies (IMAS), Private Bag 129, Hobart, TAS 7001, Australia
2CNRS/Université Aix-Marseille, CEREGE, 13545 Aix-en-Provence, Cedex 4, France
3INRIA (French National Institute for Research in Computer Science and Automatic Control), BIOCORE, 2004 Route des Lucioles, 06902 Sophia-Antipolis, France
4UPMC Univ Paris 06, UMR 7093, LOV, Observatoire océanologique, 06234 Villefranche/mer, France
5CNRS, UMR 7093, LOV, Observatoire océanologique, 06234 Villefranche/mer, France
Abstract. Coccolithophores, a key phytoplankton group, are one of the most studied organisms regarding their physiological response to ocean acidification/carbonation. The biogenic production of calcareous coccoliths has made coccolithophores a promising group for paleoceanographic research aiming to reconstruct past environmental conditions. Recently, geochemical and morphological analyses of fossil coccoliths have gained increased interest in regard to changes in seawater carbonate chemistry. The cosmopolitan coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler was cultured over a range of pCO2 levels in controlled laboratory experiments under nutrient replete and nitrogen limited conditions. Measurements of photosynthesis and calcification revealed, as previously published, an increase in particulate organic carbon production and a moderate decrease in calcification from ambient to elevated pCO2. The enhancement in particulate organic carbon production was accompanied by an increase in cell diameter. Changes in coccolith volume were best correlated with the coccosphere/cell diameter and no significant correlation was found between the coccolith volume and the particulate inorganic carbon production. The conducted experiments revealed that the coccolith volume of E. huxleyi is variable with aquatic CO2 concentration but its sensitivity is rather small in comparison with its sensitivity to nitrogen limitation. Comparing coccolith morphological and geometrical parameters like volume, mass and size to physiological parameters under controlled laboratory conditions is an important step to understand variations in fossil coccolith geometry.

Citation: Müller, M. N., Beaufort, L., Bernard, O., Pedrotti, M. L., Talec, A., and Sciandra, A.: Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta), Biogeosciences, 9, 4155-4167,, 2012.
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