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| Titel |
Variability in the partition coefficients for Mg and Sr in the shells of the ostracod “Heterocypris salina” |
| VerfasserIn |
I. Sayyad, P. Anadon, M. Martín-Rubio, F. Robles, J. Rodríguez-Lázaro, R. Utrilla, A. Vázquez |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250028429
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| Zusammenfassung |
| The partition coefficients of trace elements in ostracod shells (KdMe = Me/Cavalve /
Me/Cawater, in molar ratios), mainly for Mg and Sr, have been widely used for the
reconstruction of paleoenvironments. In order to settle these coefficients for Heterocypris
salina, juvenile individuals of this ostracod species were grown up to the adult stage in
culture experiments in 5 waters with a wide range of hydrochemistry (Mg/Caw range from
0.5 to 12, Sr/Caw range from 0.005 to 0.02), conductivity (1-17 mS/cm) and at 4 constant
temperatures (18, 20, 25, 28ºC). From our experiments, Mg/Ca and Sr/Ca molar ratios of the
valve calcite are directly related to the Mg/Ca and Sr/Ca of the water respectively, and to
the temperature of the water (Tw). In the case of Mg/Ca the temperature change
has equal effect in the whole studied range of Mg/Caw, whereas for the Sr/Ca the
temperature effect is greater at high Sr/Caw. Moreover, Mg/Ca in the valve calcite
has a good correlation to the [Mg] in water. KdMg displays very high and diverse
values (0.004-0.016) at low Mg/Caw (< 2). At high Mg/Caw, KdMg displays small
variations, and its dispersion can be explained by the Tw: the higher the Tw, the higher
the value of the coefficient for a given Mg/Caw. Neither the conductivity nor the
[Ca] in water appear to have a clear effect on the KdMg. KdSr values are nearly
constant, but they increase slightly with the Sr/Caw and with the Tw. Other water
parameters such as conductivity, [Sr], [Ca], or Mg/Caw, do not seem to have effect on the
KdSr.
This work has been funded by the Spanish Ministry of Science and Innovation
CGL-2005-01467 grant, and the BES-2006-13920 pre-doctoral grant (I. Sayyad). |
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