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Biogeosciences, 7, 1335-1347, 2010
www.biogeosciences.net/7/1335/2010/ doi:10.5194/bg-7-1335-2010 © Author(s) 2010. This work is distributed under the Creative Commons Attribution 3.0 License. |
A culture-based calibration of benthic foraminiferal paleotemperature proxies: δ18O and Mg/Ca results
1GeoBiosphere Science Centre, Dept. of Geology, Quaternary Sciences, Lund University, Sölvegatan 12, 22362 Lund, Sweden
2Geology and Geophysics Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
3Dept. of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Abstract. Benthic foraminifera were cultured for five months at four temperatures (4, 7, 14 and 21 °C) to establish the temperature dependence of foraminiferal calcite δ18O and Mg/Ca. Two Bulimina species (B. aculeata and B. marginata) were most successful in terms of calcification, adding chambers at all four temperatures and reproducing at 7 and 14 °C. Foraminiferal δ18O values displayed ontogenetic variations, with lower values in younger individuals. The δ18O values of adult specimens decreased with increasing temperature in all but the 4 °C treatment, exhibiting a relationship consistent with previous δ18O paleotemperature calibration studies. Foraminiferal Mg/Ca values, determined by laser ablation inductively coupled plasma mass spectrometry, were broadly consistent with previous Mg/Ca calibration studies, but extremely high values in the 4 °C treatment and higher than predicted values at two of the other three temperatures make it challenging to interpret these results.
Citation: Filipsson, H. L., Bernhard, J. M., Lincoln, S. A., and McCorkle, D. C.: A culture-based calibration of benthic foraminiferal paleotemperature proxies: δ18O and Mg/Ca results, Biogeosciences, 7, 1335-1347, doi:10.5194/bg-7-1335-2010, 2010.