ABSTRACT The largest radiation of Phanerozoic marine animal life quadrupled genus-level diversity towards the end of the Ordovician Period about 450 million years ago. A leading hypothesis

for this Great Ordovician Biodiversification Event is that cooling of the Ordovician climate lowered sea surface temperatures into the thermal tolerance window of many animal groups, such as

corals. A complementary role for oxygenation of subsurface environments has been inferred based on the increasing abundance of skeletal carbonate, but direct constraints on atmospheric O2

levels remain elusive. Here, we use high-resolution paired bulk carbonate and organic carbon isotope records to determine the changes in isotopic fractionation between these phases

balance. We conclude that that oxygen levels probably played an important role in regulating early Palaeozoic biodiversity levels, even after the Cambrian Explosion. Access through your

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THE BALTOSCANDIAN SHELF LINKED TO ORDOVICIAN BIODIVERSIFICATION Article Open access 12 October 2023 SUSTAINED INCREASES IN ATMOSPHERIC OXYGEN AND MARINE PRODUCTIVITY IN THE NEOPROTEROZOIC

AND PALAEOZOIC ERAS Article Open access 02 July 2024 DEGLACIAL RESTRUCTURING OF THE EASTERN EQUATORIAL PACIFIC OXYGEN MINIMUM ZONE Article Open access 27 June 2022 REFERENCES * Sepkoski, J.

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Ohio State Univ. (2014). Download references ACKNOWLEDGEMENTS J. Houghton is thanked for valuable discussions in improving earlier versions of this paper. This paper is a contribution to

IGCP Projects 591 and 653. Funding was provided in part by the Evolving Earth Foundation (CTE), a Geological Society of America Graduate Student Research Grant (CTE), a Paleontological

Society Student Research Grant (CTE) and NSF Grants EAR-0819832 and EAR-0745452 (M.R.S.). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Geological and Environmental Sciences,

Appalachian State University, Boone, NC, USA Cole T. Edwards * School of Earth Sciences, The Ohio State University, Columbus, OH, USA Matthew R. Saltzman * Department of Earth and

Environmental Sciences, Wesleyan University, Middletown, CT, USA Dana L. Royer * Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, USA David A.

Fike Authors * Cole T. Edwards View author publications You can also search for this author inPubMed Google Scholar * Matthew R. Saltzman View author publications You can also search for

this author inPubMed Google Scholar * Dana L. Royer View author publications You can also search for this author inPubMed Google Scholar * David A. Fike View author publications You can also

search for this author inPubMed Google Scholar CONTRIBUTIONS This project was conceived by C.T.E. and M.R.S. with input from D.L.R. and D.A.F. Isotopic data preparation and analysis was

done by C.T.E. Modelling was conducted by C.T.E. with input from D.L.R. The manuscript was developed by C.T.E. and received equal contributions from all authors on editing the final

manuscript. CORRESPONDING AUTHOR Correspondence to Cole T. Edwards. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. ADDITIONAL INFORMATION

PUBLISHER’S NOTE: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. ELECTRONIC SUPPLEMENTARY MATERIAL SUPPLEMENTARY

INFORMATION Supplementary discussion and figures SUPPLEMENTARY TABLE 1 Binned isotope data used for GEOCARB and model results of O2 and CO2 SUPPLEMENTARY TABLE 2 Isotope data and atmospheric

O2 using the photosynthetic fractionation effect approach SUPPLEMENTARY TABLE 3 New δ13C and δ34S data used in the photosynthetic fractionation effect and GEOCARB models SUPPLEMENTARY TABLE

4 Taxonomic data used to construct the biodiversity curve RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Edwards, C.T., Saltzman, M.R., Royer, D.L. _et

al._ Oxygenation as a driver of the Great Ordovician Biodiversification Event. _Nature Geosci_ 10, 925–929 (2017). https://doi.org/10.1038/s41561-017-0006-3 Download citation * Received: 29

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