Marine anoxia and delayed Earth system recovery after the end-Permian extinction

Kimberly V. Lau, Kate Maher, Demir Altiner, Brian M. Kelley, Lee R. Kump, Daniel J. Lehrmann, Juan Carlos Silva-Tamayo, Karrie L. Weaver, Meiyi Yu, Jonathan L. Payne

Research output: Contribution to journalArticlepeer-review

228 Scopus citations


Delayed Earth system recovery following the end-Permian mass extinction is often attributed to severe ocean anoxia. However, the extent and duration of Early Triassic anoxia remains poorly constrained. Here we use paired records of uranium concentrations ([U]) and 238U/235U isotopic compositions (δ238U) of Upper Permian-Upper Triassic marine limestones from China and Turkey to quantify variations in global seafloor redox conditions. We observe abrupt decreases in [U] and δ238U across the end-Permian extinction horizon, from ∼3 ppm and -0.15‰ to ∼0.3 ppm and -0.77‰, followed by a gradual return to preextinction values over the subsequent 5 million years. These trends imply a factor of 100 increase in the extent of seafloor anoxia and suggest the presence of a shallow oxygen minimum zone (OMZ) that inhibited the recovery of benthic animal diversity and marine ecosystem function. We hypothesize that in the Early Triassic oceans - characterized by prolonged shallow anoxia that may have impinged onto continental shelves - global biogeochemical cycles and marine ecosystem structure became more sensitive to variation in the position of the OMZ. Under this hypothesis, the Middle Triassic decline in bottom water anoxia, stabilization of biogeochemical cycles, and diversification of marine animals together reflect the development of a deeper and less extensive OMZ, which regulated Earth system recovery following the end-Permian catastrophe.

Original languageEnglish (US)
Pages (from-to)2360-2365
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number9
StatePublished - Mar 1 2016

All Science Journal Classification (ASJC) codes

  • General


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