Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere
Date
18/12/2015Author
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Abstract
Neoproterozoic (1,000–542 Myr ago) Earth experienced profound environmental change, including ‘snowball’ glaciations, oxygenation and the appearance of animals. However, an integrated understanding of these events remains elusive, partly because proxies that track subtle oceanic or atmospheric redox trends are lacking. Here we utilize selenium (Se) isotopes as a tracer of Earth redox conditions. We find temporal trends towards lower δ82/76Se values in shales before and after all Neoproterozoic glaciations, which we interpret as incomplete reduction of Se oxyanions. Trends suggest that deep-ocean Se oxyanion concentrations increased because of progressive atmospheric and deep-ocean oxidation. Immediately after the Marinoan glaciation, higher δ82/76Se values superpose the general decline. This may indicate less oxic conditions with lower availability of oxyanions or increased bioproductivity along continental margins that captured heavy seawater δ82/76Se into buried organics. Overall, increased ocean oxidation and atmospheric O2 extended over at least 100 million years, setting the stage for early animal evolution.
Citation
Pogge von Strandmann , P , Stueeken , E E , Elliott , T , Poulton , S , Dehler , C , Canfield , D & Catling , D 2015 , ' Selenium isotope evidence for progressive oxidation of the Neoproterozoic biosphere ' , Nature Communications , vol. 6 , 10157 , pp. 1-10 . https://doi.org/10.1038/ncomms10157
Publication
Nature Communications
Status
Peer reviewed
ISSN
2041-1723Type
Journal article
Rights
© 2015 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
Description
This study was funded by NERC grant NE/F016832/1. P.A.E.P.v.S. is supported by NERC fellowship NE/I020571/2.Collections
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