Metabolically diverse primordial microbial communities in Earth's oldest seafloor-hydrothermal jasper

Dominic Papineau; Zhenbing She; Matthew S Dodd; Francesco Iacoviello; John F Slack; Erik Hauri; Paul Shearing; Crispin T S Little

doi:10.1126/sciadv.abm2296

Metabolically diverse primordial microbial communities in Earth's oldest seafloor-hydrothermal jasper

Sci Adv. 2022 Apr 15;8(15):eabm2296. doi: 10.1126/sciadv.abm2296. Epub 2022 Apr 13.

Authors

Dominic Papineau^{1

2

3

4}, Zhenbing She¹, Matthew S Dodd¹, Francesco Iacoviello⁵, John F Slack^{6

7}, Erik Hauri⁸, Paul Shearing⁵, Crispin T S Little⁹

Affiliations

¹ State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China.
² London Centre for Nanotechnology, University College London, London, UK.
³ Department of Earth Sciences, University College London, London, UK.
⁴ Centre for Planetary Sciences, University College London & Birkbeck College London, London, UK.
⁵ Department of Chemical Engineering, University College London, London, UK.
⁶ U.S. Geological Survey National Center, Reston, VA, USA.
⁷ Department of Earth Sciences, Memorial University of Newfoundland, St. John's, NL, Canada.
⁸ Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC, USA.
⁹ School of Earth and Environment, University of Leeds, Leeds, UK.

Abstract

The oldest putative fossils occur as hematite filaments and tubes in jasper-carbonate banded iron formations from the 4280- to 3750-Ma Nuvvuagittuq Supracrustal Belt, Québec. If biological in origin, these filaments might have affinities with modern descendants; however, if abiotic, they could indicate complex prebiotic forms on early Earth. Here, we report images of centimeter-size, autochthonous hematite filaments that are pectinate-branching, parallel-aligned, undulated, and containing Fe²⁺-oxides. These microstructures are considered microfossils because of their mineral associations and resemblance to younger microfossils, modern Fe-bacteria from hydrothermal environments, and the experimental products of heated Fe-oxidizing bacteria. Additional clusters of irregular hematite ellipsoids could reflect abiotic processes of silicification, producing similar structures and thus yielding an uncertain origin. Millimeter-sized chalcopyrite grains within the jasper-carbonate rocks have ³⁴S- and ³³S-enrichments consistent with microbial S-disproportionation and an O₂-poor atmosphere. Collectively, the observations suggest a diverse microbial ecosystem on the primordial Earth that may be common on other planetary bodies, including Mars.