Imperial College London
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ProfessorTinavan de Flierdt

Faculty of Engineering, Department of Earth Science & Engineering

Head of the Department of Earth Science and Engineering
 
 
 
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Contact

 

+44 (0)20 7594 1290tina.vandeflierdt

 
 
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Location

 

G.30Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Xie:2019:10.1016/j.epsl.2019.02.001,
author = {Xie, RC and Rehkamper, M and Grasse, P and van, de Flierdt T and Frank, M and Xue, Z},
doi = {10.1016/j.epsl.2019.02.001},
journal = {Earth and Planetary Science Letters},
pages = {134--146},
title = {Isotopic evidence for complex biogeochemical cycling of Cd in the eastern tropical South Pacific},
url = {http://dx.doi.org/10.1016/j.epsl.2019.02.001},
volume = {512},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Over the past decades, observations have confirmed decreasing oxygen levels and shoaling of oxygen minimum zones (OMZs) in the tropical oceans. Such changes impact the biogeochemical cycling of micronutrients such as Cd, but the potential consequences are only poorly constrained. Here, we present seawater Cd concentrations and isotope compositions for 12 depth profiles at coastal, nearshore and offshore stations from 4ºS to 14ºS in the eastern tropical South Pacific, where one of the world’s strongest OMZs prevails.The depth profiles of Cd isotopes display high δ114/110 Cd at the surface and decreasing δ114/110 Cd with increasing water depth, consistent with preferential utilization of lighter Cd isotopes during biological uptake in the euphotic zone and subsequent remineralization of the sinking biomass. In the surface and subsurface ocean, seawater displays similar δ114/110 Cd signatures of 0.47 ±0.23‰ to 0.82±0.05‰ across the entire eastern tropical South Pacific despite highly variable Cd concentrations between 0.01 and 0.84 nmol/kg. This observation, best explained by an open system steady-state fractionation model, contrasts with previous studies of the South Atlantic and South Pacific Oceans, where only Cd-deficient waters have a relatively constant Cd isotope signature. For the subsurface to about 500 m depth, the variability of seawater Cd isotope compositions can be modeled by mixing of remineralized Cd with subsurface water from the base of the mixed layer. In the intermediate and deep eastern tropical South Pacific (>500 m), seawater [Cd] and δ114/110 Cd appear to follow the distribution and mixing of major water masses. We identified modified AAIW of the ETSP to be more enriched in [Cd] than AAIW from the source region, whilst both water masses have similar δ114/110 Cd. A mass balance estimate thus constrains a δ114/110 Cd of between 0.38‰ and 0.56‰ for the
AU  - Xie,RC
AU  - Rehkamper,M
AU  - Grasse,P
AU  - van,de Flierdt T
AU  - Frank,M
AU  - Xue,Z
DO  - 10.1016/j.epsl.2019.02.001
EP  - 146
PY  - 2019///
SN  - 0012-821X
SP  - 134
TI  - Isotopic evidence for complex biogeochemical cycling of Cd in the eastern tropical South Pacific
T2  - Earth and Planetary Science Letters
UR  - http://dx.doi.org/10.1016/j.epsl.2019.02.001
UR  - http://hdl.handle.net/10044/1/66216
VL  - 512
ER  -
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