Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 11, issue 23
Biogeosciences, 11, 7077–7095, 2014
https://doi.org/10.5194/bg-11-7077-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 11, 7077–7095, 2014
https://doi.org/10.5194/bg-11-7077-2014
© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 12 Dec 2014

Research article | 12 Dec 2014

I/Ca ratios in benthic foraminifera from the Peruvian oxygen minimum zone: analytical methodology and evaluation as a proxy for redox conditions

N. Glock2,1, V. Liebetrau2, and A. Eisenhauer2 N. Glock et al.
  • 1Sonderforschungsbereich 754, Christian Albrechts University Kiel, Climate Biogeochemistry Interactions in the Tropical Ocean, Kiel, Germany
  • 2GEOMAR Helmholtz-Institut für Ozeanforschung, Wischhofstr. 1–3, 24148 Kiel, Germany

Abstract. In this study, we explore the correlation of I/Ca ratios in three calcitic and one aragonitic foraminiferal species. I/Ca ratios are evaluated as possible proxies for changes in ambient redox conditions across the Peruvian oxygen minimum zone to the ambient oxygen concentrations in the habitat of the foraminiferal species studied. Cleaning and measurement methods for the determination of I/Ca ratios are tested. All species show a positive trend in their I/Ca ratios as a function of higher oxygen concentrations. The most promising species appears to be Uvigerina striata, which shows a highly statistically significant correlation between I/Ca ratios and bottom water (BW) oxygenation (I/Ca = 0.032(±0.004) × [O2]BW + 0.29(±0.03), R2 = 0.61, F = 75, P < 0.0001). Only for the aragonitic species Hoeglundina elegans is this relationship not significant. The iodine volatility in acidic solutions, the species dependency of I/Ca–[O2]BW correlations, and the individual variability of single tests, need to be accounted for when applying the I/Ca ratio as a proxy for redox conditions.

Publications Copernicus
Download
Short summary
Our study explores the correlation of I/Ca ratios in four benthic foraminiferal species (three calcitic, one aragonitic) from the Peruvian OMZ with bottom water oxygenation ([O2]BW), and evaluates foraminiferal I/Ca ratios as a possible redox proxy. All species have a positive trend in the I/Ca ratios as a function of [O2]BW. Only for the aragonitic species Hoeglundina elegans is this trend not significant. The highest significance has been found for Uvigerina striata.
Our study explores the correlation of I/Ca ratios in four benthic foraminiferal species (three...
Citation