title: Rise to modern levels of ocean oxygenation coincided with the Cambrian radiation of animals.
abstract: The early diversification of animals (∼ 630 Ma), and their development into both motile and macroscopic forms (∼ 575-565 Ma), has been linked to stepwise increases in the oxygenation of Earth's surface environment. However, establishing such a linkage between oxygen and evolution for the later Cambrian 'explosion' (540-520 Ma) of new, energy-sapping body plans and behaviours has proved more elusive. Here we present new molybdenum isotope data, which demonstrate that the areal extent of oxygenated bottom waters increased in step with the early Cambrian bioradiation of animals and eukaryotic phytoplankton. Modern-like oxygen levels characterized the ocean at ∼ 521 Ma for the first time in Earth history. This marks the first establishment of a key environmental factor in modern-like ecosystems, where animals benefit from, and also contribute to, the 'homeostasis' of marine redox conditions.
authors.affiliation: State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
authors.forename: Xi
authors.identifier: 000000017098607X
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
authors.forename: Hong-Fei
authors.initials: HF
authors.lastname: Ling
authors.affiliation: Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH, Zürich CH-8092, Switzerland.
authors.forename: Derek
authors.initials: D
authors.lastname: Vance
authors.affiliation: 1] Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK [2] State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, China.
authors.forename: Graham A
authors.identifier: 0000000278283966
authors.initials: GA
authors.lastname: Shields-Zhou
authors.affiliation: State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, China.
authors.forename: Maoyan
authors.initials: M
authors.lastname: Zhu
authors.affiliation: School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Simon W
authors.initials: SW
authors.lastname: Poulton
authors.affiliation: Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Lawrence M
authors.initials: LM
authors.lastname: Och
authors.affiliation: 1] State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China [2] State Key Laboratory of Geological Processes and Mineral Resources, Department of Resource Science and Engineering, Faculty of Earth Resources, China University of Geosciences, Wuhan 430074, China.
authors.forename: Shao-Yong
authors.initials: SY
authors.lastname: Jiang
authors.affiliation: State Key Laboratory for Mineral Deposits Research, Department of Earth Sciences, School of Earth Sciences and Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
authors.forename: Da
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cremonese
authors.affiliation: Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH, Zürich CH-8092, Switzerland.
authors.forename: Corey
authors.initials: C
authors.lastname: Archer
mesh_terms: D000818:Animals; D001272:Atmosphere; D005075:Biological Evolution; D018534:Earth, Planet; D017753:Ecosystem; D004777:Environment; D005580:Fossils; D019015:Geologic Sediments; D006706:Homeostasis; D007501:Iron / Q000737:chemistry; D007554:Isotopes; D008982:Molybdenum / Q000737:chemistry; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D012623:Seawater
chemical_list: D007554:Isotopes; D008982:Molybdenum; D007501:Iron; D010100:Oxygen