Scientia Marina, Vol 77, No S1 (2013)

Elemental composition of coccoliths: Mg/Ca relationships

Lluïsa Cros
Institut de Ciències del Mar, CSIC , Spain

José Manuel Fortuño
Institut de Ciències del Mar, CSIC , Spain

Marta Estrada
Institut de Ciències del Mar, CSIC , Spain


Coccolithophores produce calcium carbonate platelets, the coccoliths, and play a significant role in the C and Ca cycles. Coccoliths are important components of marine biogenic carbonate sediments and their chemical analysis can provide tools for paleoceanographic investigation. In particular, the Mg/Ca ratio of coccoliths has been proposed as a paleotemperature proxy. The present study uses X-ray microanalysis to evaluate the Ca and Mg composition of heterococcoliths and holococcoliths of different coccolithophore species. Our measurements indicate that the Mg values in heterococcoliths do not exceed a low threshold and do not show any consistent relationship with the Ca content, while the Mg content of holococcoliths spans a wider range, can reach much higher values and shows a linear relationship with the Ca content. Several heterococcolithophore species tend to form separate clusters according to their Mg and Ca values. Within each cluster, there were no consistent differences in the Mg/Ca ratios of specimens sampled at different temperatures or seasons, suggesting that using the Mg/Ca ratio as a paleothermometer may be problematic. Our findings could have implications for the interpretation of the fossil record because Mg-rich calcite dissolves more easily.


coccolithophores; X-ray microanalysis; calcium; magnesium; holococcoliths; heterococcoliths

Full Text:



Aubry M.-P. 2007. A major Pliocene coccolithophore turnover: Change in morphological strategy in the photic zone. In: Monechi S., Coccioni R., Rampino M.R. (eds.), Large Ecosystem Perturbations: Causes and Consequences. Geol. Soc. Am., Special Paper 424: 25-51.

Billard C., Inouye I. 2004. What is new in coccolithophore biology? In: Thierstein H.R., Young J.R. (eds), Coccolithophores: From Molecular Processes to Global Impact. Springer, pp. 1-30.

Bown P.R., Lees J.A., Young J.R. 2004. Calcareous nannoplankton evolution and diversity through time. In: Thierstein H.R., Young J.R. (eds.), Coccolithophores: From Molecular Processes to Global Impact. Springer, pp. 481-508.

Chave K.E., Deffeys K.S., Weyl P.K., Garrels R.M., Thomson M.E. 1962. Observations on the solubility of skeletal carbonate in aqueous solutions. Science 137: 33-34. PMid:17774123

Cros Miguel M.L. 2001. Planktonic coccolithophores of the NW Mediterranean. Ph.D. thesis, Univ. Barcelona, 365 pp. (Publicacions Universitat de Barcelona, 2002).

Cros L., Fortuño J.-M. 2002. Atlas of Northwestern Mediterranean coccolithophores. Sci. Mar. 66(Suppl. 1): 1-182.

Cros L., Kleijne A., Zeltner A., Billard C., Young J.R. 2000. New examples of holococcolith-heterococcolith combination coccospheres and their implications for cocolithophorid biology. Mar. Micropaleontol. 39: 1-34.

Fagerbakke K.M., Heldal M., Norland S., Heimdal B.R., Batvik H. 1994. Emiliania huxleyi. Chemical composition and size of coccoliths from enclosure experiments and a Norwegian fjord. Sarsia 79: 349-355.

Fresnel J. 1989. Les Coccolithophorides (Prymnesiophyceae) du littoral: Genres: Cricosphaera, Pleurochrysis, Cruciplacolithus, Hymenomonas et Ochrosphaera. Ultrastructure, cycle biologique, systématique. Ph.D. thesis, Univ. Caen, 281 pp.

Iglesias-Rodríguez M.D., Schofield O.M., Badley J., Medlin L.K., Hayes P.K. 2006. Intraspecific genetic diversity in the marine coccolithophore Emiliania huxleyi (Prymnesiophyceae): the use of microsatellite analysis in marine phytoplankton population studies. J. Phycol. 42: 526-536.

Mann S., Sparks N.H.C. 1988. Single Crystalline Nature of Coccolith Elements of the Marine Alga Emiliania huxleyi as Determined by Electron Diffraction and High- resolution Transmission. Proc. R. Soc. Lond. B 234: 441-453.

Manton I., Leedale G.F. 1963. Observations on the microanatomy of Crystallolithus hyalinus Gaarder and Markali. Arch. Mikrobiol. 47: 115-136.

Manton I., Leedale G.F. 1969. Observations on the microanatomy of Coccolithus pelagicus and Cricosphaera carterae, with special reference to the origin and nature of coccoliths and scales. J. Mar. Biol. Ass. U. K. 49: 1-16.

Orr J.C., Fabry V.J., Aumont O., Bopp L., Doney S.C., Feely R.A., Gnanadesikan A., Gruber N., Ishida A., Joos F., Key R.M., Lindsay K., Maier-Reimer E., Matear R., Monfray P., Mouchet A., Najjar R.G., Plattner G.-K., Rodgers K.B., Sabine C.L., Sarmiento J.L., Schlitzer R., Slater R.D., Totterdell I.J., Weirig M.-F., Yamanaka Y., Yool A. 2005. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437: 681-686. PMid:16193043

Parke M., Adams I. 1960. The motile (Crystallolithus hyalinus Gaarder & Markali) and non-motile phases in the life history of Coccolithus pelagicus (Wallich) Schiller. J. Mar. Biol. Ass. U.K. 39: 263-274.

Pienaar R.N. 1994. Ultrastructure and calcification of coccolithophores. In: Winter A., Siesser W.G. (eds.), Coccolithophores. Cambridge Univ. Press, pp. 13-37.

Probert I., Fresnel J., Billard C., Geisen, M., Young J.R. 2007. Light Electron Microscope observations of Algirosphaera robusta (Prymnesiophyceae). J. Phycol. 43: 319-332.

Rowson J.D., Leadbeater B.S.C., Green, J.C. 1986. Calcium carbonate deposition in the motile (Crystallolithus) phase of Coccolithus pelagicus (Prymnesiophyceae). Br. Phycol. J. 21: 359-370.

Rushdi A., Chen C.-T., Suess E. 1998. The solubility of calcite in seawater solution of different magnesium concentrations at 25ºC and 1 atm total pressure: a laboratory re-examination. La mer 36: 9-22.

Ra K., Kitagawa H., Shiraiwa Y. 2010. Mg isotopes and Mg/Ca values of coccoliths from cultured specimens of the species Emiliania huxleyi and Gephyrocapsa oceanica. Mar. Micropaleontol. 77: 119-124.

Siesser W.G. 1977. Chemical Composition of Calcareous Nannofossils. S. Afr. J. Sci. 73: 283-285.

Siesser W.G., Winter A. 1994. Composition and morphology of coccolithophore skeletons. In: Winter A., Siesser W.G. (eds.), Coccolithophores. Cambridge Univ. Press, pp. 51-62.

Stanley S.M., Hardie L.A. 1998. Secular oscillations in the carbonate mineralogy of reef-building and sediment-producing organisms driven by tectonically forced shifts in seawater chemistry. Palaeogeogr. Palaeoclimatol. Palaeoecol. 144: 3-19.

Stanley S.M., Ries J.B., Hardie L.A. 2005. Seawater chemistry, coccolithophore population growth and the origin of Cretaceous chalk. Geology 33: 593-596.

Stoll H.M, Ruiz Encinar J., Garcia Alonso I., Rosenthal Y., Probert I., Klaas C. 2001. A first look at paleotemperature prospects from Mg in coccolith carbonate: cleaning techniques and culture measurements. Geochem. Geophys. Geosyst. 2, 1047, doi: 10.1029/2000GC000144.

Stoll H.M., Shimizu N., Ziveri P., Archer D. 2007. Coccolithophore productivity response to greenhouse event of the Paleocene-Eocene thermal maximum. Earth Planet. Sci. Lett. 258: 192-206.

Tynan S., Opdyke B. 2011. Effects of lower surface ocean pH upon the stability of shallow water carbonate sediments. Sci. Total Environ. 409: 1082-1086. PMid:21211824

Westbroek P., Brown C.W., van Bleijswijk J., Brownlee C., Brummer G.J., Conte M., Egge J., Fernandez E., Jordan R.W., Knappertsbusch M., Stefels J., Veldhuis M., van der Wal P., Young, J.R. 1993. A model system approach to biological climate forcing. The example of Emiliania huxleyi. Global Planet. Change 8: 27-46.

Young J.R., Davis S.A., Bown P.R., Mann S. 1999. Coccolith ultrastructure and biomineralisation. J. Struct. Biol. 126: 195-215. PMid:10441529

Copyright (c) 2013 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Contact us

Technical support