I/Ca ratios in benthic foraminifera from the Peruvian oxygen minimum zone: analytical methodology and evaluation as a proxy for redox conditions
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 th...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-12-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/11/7077/2014/bg-11-7077-2014.pdf |
| Summary: | 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 <i>Uvigerina
striata</i>, which shows a highly statistically significant correlation between
I/Ca ratios and bottom water (BW) oxygenation
(I/Ca = 0.032(±0.004) × [O<sub>2</sub>]<sub>BW</sub> +
0.29(±0.03), <i>R</i><sup>2</sup> = 0.61, <i>F</i> = 75, <i>P</i> < 0.0001). Only for
the aragonitic species <i>Hoeglundina elegans</i> is this relationship not
significant. The iodine volatility in acidic solutions, the species
dependency of I/Ca–[O<sub>2</sub>]<sub>BW</sub> 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. |
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| ISSN: | 1726-4170 1726-4189 |