Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 14, issue 3
Biogeosciences, 14, 497–510, 2017
https://doi.org/10.5194/bg-14-497-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 14, 497–510, 2017
https://doi.org/10.5194/bg-14-497-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 02 Feb 2017

Research article | 02 Feb 2017

Trends in element incorporation in hyaline and porcelaneous foraminifera as a function of pCO2

Inge van Dijk1, Lennart J. de Nooijer1, and Gert-Jan Reichart1,2 Inge van Dijk et al.
  • 1Department of Ocean Systems, NIOZ-Royal Netherlands Institute for Sea Research and Utrecht University, Postbus 59, 1790 AB, Den Burg, the Netherlands
  • 2Faculty of Geosciences, Earth Sciences Department, Utrecht University, Budapestlaan 4, 3584 CD, Utrecht, the Netherlands

Abstract. In this study we analyzed the impact of seawater carbonate chemistry on the incorporation of elements in both hyaline and porcelaneous larger benthic foraminifera. We observed a higher incorporation of Zn and Ba when pCO2 increases from 350 to 1200 ppm. Modeling the activity of free ions as a function of pCO2 shows that speciation of some elements (like Zn and Ba) is mainly influenced by the formation of carbonate complexes in seawater. Hence, differences in foraminiferal uptake of these might be related primarily by the speciation of these elements in seawater. We investigated differences in trends in element incorporation between hyaline (perforate) and porcelaneous (imperforate) foraminifera in order to unravel processes involved in element uptake and subsequent foraminiferal calcification. In hyaline foraminifera we observed a correlation of element incorporation of different elements between species, reflected by a general higher incorporation of elements in species with higher Mg content. Between porcelaneous species, inter-element differences are much smaller. Besides these contrasting trends in element incorporation, however, similar trends are observed in element incorporation as a function of seawater carbonate chemistry in both hyaline and porcelaneous species. This suggests similar mechanisms responsible for the transportation of ions to the site of calcification for these groups of foraminifera, although the contribution of these processes might differ across species.

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Culturing foraminifera under controlled pCO2 conditions shows that incorporation of certain elements (Zn, Ba) into foraminiferal shells is impacted by the inorganic carbonate system. Modeling the chemical speciation of these elements suggests that incorporation is determined by the availability of free ions. Furthermore, analyzing and comparing trends in element incorporation in hyaline and porcelaneous species may provide constrains on the differences between their calcification strategies.
Culturing foraminifera under controlled pCO2 conditions shows that incorporation of certain...
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