Organic sulfur was integral to the Archean sulfur cycle

Mojtaba Fakhraee, Sergei Katsev

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


The chemistry of the Early Earth is widely inferred from the elemental and isotopic compositions of sulfidic sedimentary rocks, which are presumed to have formed globally through the reduction of seawater sulfate or locally from hydrothermally supplied sulfide. Here we argue that, in the anoxic Archean oceans, pyrite could form in the absence of ambient sulfate from organic sulfur contained within living cells. Sulfides could be produced through mineralization of reduced sulfur compounds or reduction of organic-sourced sulfite. Reactive transport modeling suggests that, for sulfate concentrations up to tens of micromolar, organic sulfur would have supported 20 to 100% of sedimentary pyrite precipitation and up to 75% of microbial sulfur reduction. The results offer an alternative explanation for the low range of δ34S in Archean sulfides, and raise a possibility that sulfate scarcity delayed the evolution of dissimilatory sulfate reduction until the initial ocean oxygenation around 2.7 Ga.

Original languageEnglish (US)
Article number4556
JournalNature communications
Issue number1
StatePublished - Dec 1 2019

Bibliographical note

Publisher Copyright:
© 2019, The Author(s).


Dive into the research topics of 'Organic sulfur was integral to the Archean sulfur cycle'. Together they form a unique fingerprint.

Cite this