Substrate supply for calcite precipitation in Emiliania huxleyi: assessment of different model approaches

Holtz, Lena-Maria and Thoms, Silke and Langer, Gerald and Wolf-Gladrow, Dieter A. (2013) Substrate supply for calcite precipitation in Emiliania huxleyi: assessment of different model approaches. Journal of Phycology, 49 (2). pp. 417-426. ISSN 0022-3646, ESSN: 1529-8817 DOI https://doi.org/10.1111/jpy.12052

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Abstract

Over the last four decades, different hypotheses of Ca2+ and dissolved inorganic carbon transport to the intracellular site of calcite precipitation have been put forth for Emiliania huxleyi (Lohmann) Hay & Mohler. The objective of this study was to assess these hypotheses by means of mathematical models. It is shown that a vesicle-based Ca2+ transport would require very high intravesicular Ca2+ concentrations, high vesicle fusion frequencies as well as a fast membrane recycling inside the cell. Furthermore, a kinetic model for the calcification compartment is presented that describes the internal chemical environment in terms of carbonate chemistry including calcite precipitation. Substrates for calcite precipitation are transported with different stoichiometries across the compartment membrane. As a result, the carbonate chemistry inside the compartment changes and hence influences the calcification rate. Moreover, the effect of carbonic anhydrase (CA) activity within the compartment is analyzed. One very promising model version is based on a Ca2+/H+ antiport, CO2 diffusion, and a CA inside the calcification compartment. Another promising model version is based on an import of Ca2+ and HCO3− and an export of H+.

Item Type:	Article
Uncontrolled Keywords:	2013AREP; IA65;
Subjects:	04 - Palaeobiology
Divisions:	04 - Palaeobiology
Journal or Publication Title:	Journal of Phycology
Volume:	49
Page Range:	pp. 417-426
Identification Number:	https://doi.org/10.1111/jpy.12052
Depositing User:	Sarah Humbert
Date Deposited:	03 May 2013 16:53
Last Modified:	23 Jul 2013 10:06
URI:	http://eprints.esc.cam.ac.uk/id/eprint/2764

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