Lennart J. de Nooijer1, Anieke Brombacher2,a, Antje Mewes3, Gerald Langer4, Gernot Nehrke3, Jelle Bijma3, and Gert-Jan Reichart1,21Royal Netherlands Institute of Sea Research, Dept of Geology and Chemical Oceanography, Landsdiep 4, 1797 SZ ‘t Horntje, The Netherlands 2Utrecht University, Faculty of Geosciences, Budapestlaan 4, 3584 CD Utrecht, The Netherlands 3Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Biogeosciences section, Am Handelshafen 12, 27570 Bremerhaven, Germany 4The Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, Devon, PL1 2PB, UK anow at: National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK
Received: 13 Feb 2017 – Accepted for review: 14 Feb 2017 – Discussion started: 28 Feb 2017
Abstract. Barium (Ba) incorporated in the calcite of many foraminiferal species is proportional to the concentration of Ba in seawater. Since the open ocean concentration of Ba closely follows seawater alkalinity, foraminiferal Ba/Ca can be used to reconstruct the latter. Alternatively, Ba/Ca from foraminiferal shells can also be used to reconstruct salinity in coastal settings where seawater Ba concentration corresponds to salinity as rivers contain much more Ba than seawater. Incorporation of a number of minor and trace elements is known to vary (greatly) between foraminiferal species and application of element/Ca ratios thus requires the use of species-specific calibrations. Here we show that calcite Ba/Ca correlates positively and linearly with seawater Ba/Ca in cultured specimens of two species of benthic foraminifera, Heterostegina depressa and Amphistegina lessonii. The slopes of the regression, however, vary 2–3 fold between these two species (0.33 and 0.78, respectively). This difference in Ba-partitioning resembles the difference in partitioning of other elements (Mg, Sr, B, Li and Na) in these foraminiferal taxa. A general trend across element partitioning for different species is described, which may help developing new applications of trace elements in foraminiferal calcite in reconstructing past seawater chemistry.
de Nooijer, L. J., Brombacher, A., Mewes, A., Langer, G., Nehrke, G., Bijma, J., and Reichart, G.-J.: Ba incorporation in benthic foraminifera, Biogeosciences Discuss., doi:10.5194/bg-2017-45, in review, 2017.