Ocean deoxygenation after the Sturtian Snowball

Abstract The abrupt ending of the Sturtian ‘Snowball’ glaciation was characterised by enhanced chemical weathering and carbon cycle perturbations, but there is less certainty over how oxygen levels responded to those changes. Here we reconcile conflicting views using a carbonate-based multiproxy dat...

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Main Authors: Kun Zhang, Susan H. Little, Alexander J. Dickson, Graham A. Shields
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-60700-w
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author Kun Zhang
Susan H. Little
Alexander J. Dickson
Graham A. Shields
author_facet Kun Zhang
Susan H. Little
Alexander J. Dickson
Graham A. Shields
author_sort Kun Zhang
collection DOAJ
description Abstract The abrupt ending of the Sturtian ‘Snowball’ glaciation was characterised by enhanced chemical weathering and carbon cycle perturbations, but there is less certainty over how oxygen levels responded to those changes. Here we reconcile conflicting views using a carbonate-based multiproxy dataset from the Taishir Formation in Mongolia. The geochemical data reveal an episode of ocean deoxygenation, followed by a shift toward less reducing, but still largely anoxic conditions in a post-glacial ocean characterised by nutrient and sulfate limitation. Ocean redox dynamics and biogeochemical cycling following the Sturtian deglaciation were likely dictated by unique tectonic and climatic regimes that facilitated the buildup of a recalcitrant dissolved organic carbon pool in the deep ocean. Post-glacial eutrophication may help to explain the delayed diversification of algal clades, but the persistence of ocean anoxia, excepting transient oxidation pulses, likely hindered the emergence of obligate aerobes, such as animals, until the Ediacaran Period.
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institution Kabale University
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spelling doaj-art-e73d53e6f47d42da9d2ff81c19de973d2025-08-20T03:37:37ZengNature PortfolioNature Communications2041-17232025-07-0116111010.1038/s41467-025-60700-wOcean deoxygenation after the Sturtian SnowballKun Zhang0Susan H. Little1Alexander J. Dickson2Graham A. Shields3Department of Earth Sciences, University College LondonDepartment of Earth Sciences, University College LondonCentre of Climate, Ocean and Atmosphere, Department of Earth Sciences, Royal Holloway University of London, EghamDepartment of Earth Sciences, University College LondonAbstract The abrupt ending of the Sturtian ‘Snowball’ glaciation was characterised by enhanced chemical weathering and carbon cycle perturbations, but there is less certainty over how oxygen levels responded to those changes. Here we reconcile conflicting views using a carbonate-based multiproxy dataset from the Taishir Formation in Mongolia. The geochemical data reveal an episode of ocean deoxygenation, followed by a shift toward less reducing, but still largely anoxic conditions in a post-glacial ocean characterised by nutrient and sulfate limitation. Ocean redox dynamics and biogeochemical cycling following the Sturtian deglaciation were likely dictated by unique tectonic and climatic regimes that facilitated the buildup of a recalcitrant dissolved organic carbon pool in the deep ocean. Post-glacial eutrophication may help to explain the delayed diversification of algal clades, but the persistence of ocean anoxia, excepting transient oxidation pulses, likely hindered the emergence of obligate aerobes, such as animals, until the Ediacaran Period.https://doi.org/10.1038/s41467-025-60700-w
spellingShingle Kun Zhang
Susan H. Little
Alexander J. Dickson
Graham A. Shields
Ocean deoxygenation after the Sturtian Snowball
Nature Communications
title Ocean deoxygenation after the Sturtian Snowball
title_full Ocean deoxygenation after the Sturtian Snowball
title_fullStr Ocean deoxygenation after the Sturtian Snowball
title_full_unstemmed Ocean deoxygenation after the Sturtian Snowball
title_short Ocean deoxygenation after the Sturtian Snowball
title_sort ocean deoxygenation after the sturtian snowball
url https://doi.org/10.1038/s41467-025-60700-w
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