Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact

Research output: Contribution to journalArticle

Authors

  • Michael J. Henehan
  • Andy Ridgwell
  • Ellen Thomas
  • Shuang Zhang
  • Laia Alegret
  • Daniela N. Schmidt
  • James W. B. Rae
  • James D. Witts
  • Neil H. Landman
  • Brian T. Huber
  • James Super
  • Noah J. Planavsky
  • Pincelli M. Hull

Colleges, School and Institutes

External organisations

  • University of St Andrews
  • American Museum of Natural History
  • University of New Mexico
  • Yale University
  • Smithsonian Institution
  • GFZ German Research Centre for Geosciences
  • University of Bristol
  • University of California
  • Universidad de Zaragoza
  • Wesleyan University

Abstract

Mass extinction at the Cretaceous–Paleogene (K-Pg) boundary coincides with the Chicxulub bolide impact and also falls within the broader time frame of Deccan trap emplacement. Critically, though, empirical evidence as to how either of these factors could have driven observed extinction patterns and carbon cycle perturbations is still lacking. Here, using boron isotopes in foraminifera, we document a geologically rapid surface-ocean pH drop following the Chicxulub impact, supporting impact-induced ocean acidification as a mechanism for ecological collapse in the marine realm. Subsequently, surface water pH rebounded sharply with the extinction of marine calcifiers and the associated imbalance in the global carbon cycle. Our reconstructed water-column pH gradients, combined with Earth system modeling, indicate that a partial ∼50% reduction in global marine primary productivity is sufficient to explain observed marine carbon isotope patterns at the K-Pg, due to the underlying action of the solubility pump. While primary productivity recovered within a few tens of thousands of years, inefficiency in carbon export to the deep sea lasted much longer. This phased recovery scenario reconciles competing hypotheses previously put forward to explain the K-Pg carbon isotope records, and explains both spatially variable patterns of change in marine productivity across the event and a lack of extinction at the deep sea floor. In sum, we provide insights into the drivers of the last mass extinction, the recovery of marine carbon cycling in a postextinction world, and the way in which marine life imprints its isotopic signal onto the geological record.

Details

Original languageEnglish
Pages (from-to)22500-22504
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume116
Issue number45
Early online date21 Oct 2019
Publication statusPublished - 5 Nov 2019

Keywords

  • boron isotopes, Cretaceous/Paleogene boundary, GENIE model, mass extinction, ocean acidification

ASJC Scopus subject areas