Late Cenozoic intensification of deoxygenation in the Pacific Ocean

Nilsson-Kerr, Katrina ORCID: https://orcid.org/0000-0001-7379-2684; Hoogakker, Babette A.A. ORCID: https://orcid.org/0000-0002-8171-9679; Macaya, Dharma A. Reyes; Winkelbauer, Helge A.; Hamilton, Elliott ORCID: https://orcid.org/0000-0002-9437-5238; Chenery, Simon ORCID: https://orcid.org/0000-0002-4096-0183; Davis, Catherine V; Leng, Melanie J. ORCID: https://orcid.org/0000-0003-1115-5166. 2025 Late Cenozoic intensification of deoxygenation in the Pacific Ocean. Earth and Planetary Science Letters, 655, 119253. 10.1016/j.epsl.2025.119253

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Official URL: https://doi.org/10.1016/j.epsl.2025.119253

Abstract/Summary

The Pacific Ocean hosts the largest expanse of oxygen depleted waters owing to a combination of factors influencing oxygen supply and consumption, with consequences for biogeochemical cycling. However, understanding of the long-term evolution of the Pacific Oxygen Deficient Zone remains poorly constrained. Here we apply the Iodine to Calcium (I/Ca) ratio in planktic foraminifera, in combination with the absence/presence of Globorotaloides hexagonus, from four tropical Pacific Ocean sites to reconstruct oceanic oxygen across the late Cenozoic. To validate the application of I/Ca, we supplement existing I/Ca calibration datasets by expanding their spatial coverage with additional core-top measurements. Our downcore results, combined with other lines of evidence, indicate the emergence and establishment of low oxygen waters from the late Miocene-Pliocene. The decline in Pacific Ocean oxygen accompanies large-scale climate and tectonic changes and likely impacted marine carbon cycling.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.epsl.2025.119253
ISSN:	0012821X
Date made live:	31 Mar 2025 15:24 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539191

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.epsl.2025.119253

ISSN:

0012821X

Date made live:

31 Mar 2025 15:24 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/539191