TY - JOUR
T1 - Interindividual variability and ontogenetic effects on Mg and Sr incorporation in the planktonic foraminifer Globigerinoides sacculifer
AU - Dueñas-Bohórquez, Adriana
AU - da Rocha, Régine Elisabeth
AU - Kuroyanagi, Azumi
AU - de Nooijer, Lennart J.
AU - Bijma, Jelle
AU - Reichart, Gert Jan
N1 - Funding Information:
This research was funded by the Dutch Organization for Scientific Research (NWO) , under Project No. 855.01.079 (PaleoSalt), the German Research Foundation (DFG) under Grant No. BI 432/4-2 (PaleoSalt) and the European Science Foundation (ESF) under the EUROCORES Programme EuroCLIMATE through Contract No. ERAS-CT-2003-980409 of the European Commission, DG Research, FP6. The field work was carried out at the marine station of the Department of Marine Sciences, University of Puerto Rico. We thank Howard J. Spero for providing laboratory and field equipment; Bärbel Hönisch, Andrea Lenderink and Milton Carlo for assistance in the field and the collection of planktonic foraminifera. We would like to thank Paul Mason and Gijs Nobbe for assisting with the LA–ICP–MS, Helen de Waard for the ICP–AES analyses, Dineke van de Meent-Olieman for the analyses of DIC samples at Utrecht University and Karoliina A. Koho for helping us with the SEM photos of the planktonic foraminifera. We particularly wish to thank Dr. David Lea and two anonymous reviewers for their critical reviews that improved an earlier version of this manuscript.
PY - 2011/1/15
Y1 - 2011/1/15
N2 - In order to investigate the interindividual and ontogenetic effects on Mg and Sr incorporation, magnesium/calcium (Mg/Ca) and strontium/calcium (Sr/Ca) ratios of cultured planktonic foraminifera have been determined. Specimens of Globigerinoides sacculifer were grown under controlled physical and chemical seawater conditions in the laboratory. By using this approach, we minimised the effect of potential environmental variability on Mg/Ca and Sr/Ca ratios. Whereas temperature is the overriding control of Mg/Ca ratios, the interindividual variability observed in the Mg/Ca values contributes 2-3°C to the apparent temperature variance. Interindividual variability in Sr/Ca ratios is much smaller than that observed in Mg/Ca values. The variability due to ontogeny corresponds to -0.43mmol/mol of Mg/Ca ratio per chamber added. This translates into an apparent decrease of ∼1°C in Mg/Ca-based temperature per ontogenetic (chamber) stage. No significant ontogenetic effect is observed on Sr incorporation. We conclude that the presence of a significant ontogenetic effect on Mg incorporation can potentially offset Mg/Ca-based temperature reconstructions. We propose two new empirical Mg/Ca-temperature equation based on Mg/Ca measurements of the last four ontogenetic (chamber) stages and whole foraminiferal test: Mg/Ca=(0.55(±0.03)-0.0002(±4×10-5) MSD)e0.089T and, Mg/Ca=(0.55(±0.03)-0.0001(±2×10-5) MSD)e0.089T, respectively, where MSD corresponds to the maximum shell diameter of the individual.
AB - In order to investigate the interindividual and ontogenetic effects on Mg and Sr incorporation, magnesium/calcium (Mg/Ca) and strontium/calcium (Sr/Ca) ratios of cultured planktonic foraminifera have been determined. Specimens of Globigerinoides sacculifer were grown under controlled physical and chemical seawater conditions in the laboratory. By using this approach, we minimised the effect of potential environmental variability on Mg/Ca and Sr/Ca ratios. Whereas temperature is the overriding control of Mg/Ca ratios, the interindividual variability observed in the Mg/Ca values contributes 2-3°C to the apparent temperature variance. Interindividual variability in Sr/Ca ratios is much smaller than that observed in Mg/Ca values. The variability due to ontogeny corresponds to -0.43mmol/mol of Mg/Ca ratio per chamber added. This translates into an apparent decrease of ∼1°C in Mg/Ca-based temperature per ontogenetic (chamber) stage. No significant ontogenetic effect is observed on Sr incorporation. We conclude that the presence of a significant ontogenetic effect on Mg incorporation can potentially offset Mg/Ca-based temperature reconstructions. We propose two new empirical Mg/Ca-temperature equation based on Mg/Ca measurements of the last four ontogenetic (chamber) stages and whole foraminiferal test: Mg/Ca=(0.55(±0.03)-0.0002(±4×10-5) MSD)e0.089T and, Mg/Ca=(0.55(±0.03)-0.0001(±2×10-5) MSD)e0.089T, respectively, where MSD corresponds to the maximum shell diameter of the individual.
UR - http://www.scopus.com/inward/record.url?scp=78650197632&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=78650197632&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2010.10.006
DO - 10.1016/j.gca.2010.10.006
M3 - Article
AN - SCOPUS:78650197632
VL - 75
SP - 520
EP - 532
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
IS - 2
ER -