Service interruption on Monday 11 July from 12:30 to 13:00: all the sites of the CCSD (HAL, Epiciences, SciencesConf, AureHAL) will be inaccessible (network hardware connection).
Skip to Main content Skip to Navigation
Journal articles

Proterozoic ocean redox and biogeochemical stasis

Abstract : The partial pressure of oxygen in Earth's atmosphere has increased dramatically through time, and this increase is thought to have occurred in two rapid steps at both ends of the Proterozoic Eon (~2.5-0.543 Ga). However, the trajectory and mechanisms of Earth's oxygenation are still poorly constrained, and little is known regarding attendant changes in ocean ventilation and seafloor redox.We have a particularly poor understanding of ocean chemistry during the mid-Proterozoic (~1.8-0.8 Ga). Given the coupling between redoxsensitive trace element cycles and planktonic productivity, various models for mid-Proterozoic ocean chemistry imply different effects on the biogeochemical cycling of major and trace nutrients, with potential ecological constraints on emerging eukaryotic life. Here, we exploit the differing redox behavior of molybdenum and chromium to provide constraints on seafloor redox evolution by coupling a large database of sedimentary metal enrichments to a mass balance model that includes spatially variant metal burial rates.We find that the metal enrichment record implies a Proterozoic deep ocean characterized by pervasive anoxia relative to the Phanerozoic (at least ~30-40% of modern seafloor area) but a relatively small extent of euxinic (anoxic and sulfidic) seafloor (less than ~1-10% of modern seafloor area). Our model suggests that the oceanicMo reservoir is extremely sensitive to perturbations in the extent of sulfidic seafloor and that the record of Mo and chromium enrichments through time is consistent with the possibility of a Mo-N colimited marine biosphere during many periods of Earth's history.
Document type :
Journal articles
Complete list of metadata
Contributor : AdminHAL UnivBrestBU Connect in order to contact the contributor
Submitted on : Friday, April 23, 2021 - 11:07:55 AM
Last modification on : Tuesday, May 31, 2022 - 10:20:17 AM
Long-term archiving on: : Saturday, July 24, 2021 - 6:26:19 PM


Publisher files allowed on an open archive




C. T. Reinhard, N.J. Planavsky, L. J. Robbins, C.A. Partin, B.C. Gill, et al.. Proterozoic ocean redox and biogeochemical stasis. Proceedings of the National Academy of Sciences of the United States of America, National Academy of Sciences, 2013, 110 (14), pp.5357-5362. ⟨10.1073/pnas.1208622110⟩. ⟨insu-00815464⟩



Record views


Files downloads