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| Titel |
A reappraisal of the vital effect in cultured benthic foraminifer Bulimina marginata on Mg/Ca values: assessing temperature uncertainty relationships |
| VerfasserIn |
J. C. Wit, L. J. Nooijer, C. Barras, F. J. Jorissen, G. J. Reichart |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 9 ; Nr. 9, no. 9 (2012-09-27), S.3693-3704 |
| Datensatznummer |
250007296
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| Publikation (Nr.) |
 copernicus.org/bg-9-3693-2012.pdf |
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| Zusammenfassung |
| The reconstruction of past temperatures is often achieved through measuring
the Mg/Ca value of foraminiferal test carbonate. The diversity in
foraminiferal Mg/Ca–temperature calibrations suggests that there is also a
biological control on this proxy. This study presents a new
Mg/Ca–temperature calibration for the benthic foraminifer Bulimina marginata, based on
cultures under a range of temperatures (4–14 °C). Measured Mg/Ca values
for B. marginata correlate with temperature (Mg/Ca = (1.10 ± 0.10) e(0.045±0.009)T, R2 = 0.28 p < 0.01). The inter-individual variability is,
however, also significant (standard deviation is 10–35% of the average).
Before applying this or any calibration, the effect of the inter-individual
variability on the accuracy of the Mg/Ca–temperature calibration has to be
evaluated. The inter-individual variability is quantified and split into three
components, namely (1) an analytical error, (2) an environmental effect and (3)
a vital effect. The effect of inter-individual variability on the accuracy
of Mg/Ca–temperature calibrations depends on the sensitivity of the
calibration used and the number of individuals measured (temperature
uncertainty = (0.33 · N−0.50)/sensitivity). The less sensitive a
calibration, the greater is the impact of inter-individual variability,
which can partly be circumvented by measuring more individuals. This study
shows the link between inter-individual variability and sensitivity and
quantifies their influence on the accuracy of Mg/Ca–temperature
calibrations. Differences in the sensitivity of the Mg/Ca–temperature
calibration of foraminifera may depend on the environmental conditions in
which foraminifera live and their concurring ecological strategies. |
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