TY - JOUR
T1 - Sr partitioning in the benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii
AU - Langer, Gerald
AU - Sadekov, Aleksey
AU - Thoms, Silke
AU - Keul, Nina
AU - Nehrke, Gernot
AU - Mewes, Antje
AU - Greaves, Mervyn
AU - Misra, Sambuddha
AU - Reichart, Gert Jan
AU - de Nooijer, Lennart Jan
AU - Bijma, Jelle
AU - Elderfield, Henry
PY - 2016/11/15
Y1 - 2016/11/15
N2 - The shallow water benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii were grown at different seawater Sr/Ca and the test Sr/Ca ratio was determined by Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry. A. aomoriensis test Sr/Ca is positively correlated with seawater Sr/Ca. The linear regression has a slope of 0.17, representing the overall Sr partitioning coefficient KDSr. The slope remains unchanged, if seawater Ca concentration is changed in order to change the seawater Sr/Ca. In the case of A. lessonii, the slopes of the linear regressions representing KDSr differ from one another i.e., 0.16 if the Sr concentration is changed and 0.32 if the Ca level is changed. This difference in KDSr can be explained by the, relative to A. aomoriensis, high Mg content of A. lessonii (ca. 40 mmol/mol), distorting the calcite lattice and weakening the discrimination against Sr. The Mg content of A. aomoriensis is too low (ca. 4 mmol/mol) to observe the influence on Sr partitioning. All data are compatible with a recently developed model for minor element partitioning in foraminifera (Nehrke et al., 2013; Mewes et al., 2015a). On the whole, our data confirm the model (applicability of the model to Sr and dependence of the calcite Sr/Ca on seawater Sr/Ca, as opposed to seawater Sr concentration), and improve our understanding of the model (influence of calcite Mg/Ca on Sr partitioning).
AB - The shallow water benthic foraminifera Ammonia aomoriensis and Amphistegina lessonii were grown at different seawater Sr/Ca and the test Sr/Ca ratio was determined by Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry. A. aomoriensis test Sr/Ca is positively correlated with seawater Sr/Ca. The linear regression has a slope of 0.17, representing the overall Sr partitioning coefficient KDSr. The slope remains unchanged, if seawater Ca concentration is changed in order to change the seawater Sr/Ca. In the case of A. lessonii, the slopes of the linear regressions representing KDSr differ from one another i.e., 0.16 if the Sr concentration is changed and 0.32 if the Ca level is changed. This difference in KDSr can be explained by the, relative to A. aomoriensis, high Mg content of A. lessonii (ca. 40 mmol/mol), distorting the calcite lattice and weakening the discrimination against Sr. The Mg content of A. aomoriensis is too low (ca. 4 mmol/mol) to observe the influence on Sr partitioning. All data are compatible with a recently developed model for minor element partitioning in foraminifera (Nehrke et al., 2013; Mewes et al., 2015a). On the whole, our data confirm the model (applicability of the model to Sr and dependence of the calcite Sr/Ca on seawater Sr/Ca, as opposed to seawater Sr concentration), and improve our understanding of the model (influence of calcite Mg/Ca on Sr partitioning).
KW - Biomineralization
KW - Foraminifera
KW - Minor element partitioning
UR - http://www.scopus.com/inward/record.url?scp=84981289581&partnerID=8YFLogxK
U2 - 10.1016/j.chemgeo.2016.07.018
DO - 10.1016/j.chemgeo.2016.07.018
M3 - Article
AN - SCOPUS:84981289581
SN - 0009-2541
VL - 440
SP - 306
EP - 312
JO - Chemical Geology
JF - Chemical Geology
ER -