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| Titel |
Boron incorporation in the foraminifer Amphistegina lessonii under a decoupled carbonate chemistry |
| VerfasserIn |
K. Kaczmarek, G. Langer, G. Nehrke, I. Horn, S. Misra, M. Janse, J. Bijma |
| 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 ; 12, no. 6 ; Nr. 12, no. 6 (2015-03-18), S.1753-1763 |
| Datensatznummer |
250117866
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| Publikation (Nr.) |
 copernicus.org/bg-12-1753-2015.pdf |
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| Zusammenfassung |
| A number of studies have shown that the boron isotopic composition (δ11B) and the B / Ca ratio of biogenic carbonates (mostly foraminifers)
can serve as proxies for two parameters of the ocean's carbonate chemistry,
rendering it possible to calculate the entire carbonate system. However, the
B incorporation mechanism into marine carbonates is still not fully
understood and analyses of field samples show species-specific and
hydrographic effects on the B proxies complicating their application.
Identifying the carbonate system parameter influencing boron incorporation
is difficult due to the co-variation of pH, CO32- and
B(OH)4-. To shed light on the question which parameter of the
carbonate system is related to the boron incorporation, we performed culture
experiments with the benthic symbiont-bearing foraminifer Amphistegina lessonii using a decoupled
pH–CO32- chemistry. The determination of the δ11B
and B / Ca ratios was performed simultaneously by means of a new in situ technique
combining optical emission spectroscopy and laser ablation MC-ICP-MS. The
boron isotopic composition in the tests gets heavier with increasing pH and
B / Ca increases with increasing B(OH)4- / HCO3- of the
culture media. The latter indicates that boron uptake of A. lessonii features a
competition between B(OH)4- and HCO3-. Furthermore, the
simultaneous determination of B / Ca and δ11B on single specimens
allows for assessing the relative variability of these parameters. Among
different treatments the B / Ca shows an increasing variability with
increasing boron concentration in the test whereas the variability in the
isotope distribution is constant. |
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