The coordination and distribution of B in foraminiferal calcite

Branson, Oscar and Kaczmarek, Karina and Redfern, Simon A. T. and Misra, Sambuddha and Langer, Gerald and Tyliszczak, Tolek and Bijma, Jelle and Elderfield, Henry (2015) The coordination and distribution of B in foraminiferal calcite. Earth and Planetary Science Letters, 416. pp. 67-72. ISSN 0012-821X DOI 10.1016/j.epsl.2015.02.006

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Abstract

The isotopic ratio and concentration of B in foraminiferal calcite appear to reflect the pH and bicarbonate concentration of seawater. The use of B as a chemical proxy tracer has the potential to transform our understanding of the global carbon cycle, and ocean acidification processes. However, discrepancies between the theory underpinning the B proxies, and mineralogical observations of B coordination in biomineral carbonates call the basis of these proxies into question. Here, we use synchrotron X-ray spectromicroscopy to show that B is hosted solely as trigonal BO3 in the calcite test of Amphistegina lessonii, and that B concentration exhibits banding at the micron length scale. In contrast to previous results, our observation of trigonal B agrees with the predictions of the theoretical mechanism behind B palaeoproxies. These data strengthen the use of B for producing palaeo-pH records. The observation of systematic B heterogeneity, however, highlights the complexity of foraminiferal biomineralisation, implying that B incorporation is modulated by biological or crystal growth processes.

Item Type: Article
Uncontrolled Keywords: 2015AREP; IA68;
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
03 - Mineral Sciences
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
03 - Mineral Sciences
07 - Gold Open Access
Journal or Publication Title: Earth and Planetary Science Letters
Volume: 416
Page Range: pp. 67-72
Identification Number: 10.1016/j.epsl.2015.02.006
Depositing User: Sarah Humbert
Date Deposited: 28 Mar 2015 02:29
Last Modified: 09 Apr 2015 09:39
URI: http://eprints.esc.cam.ac.uk/id/eprint/3268

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