Biosignatures of ancient microbial life are present across the igneous crust of the Fennoscandian shield
Open Access
- 3 June 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in Communications Earth & Environment
- Vol. 2 (1), 1-13
- https://doi.org/10.1038/s43247-021-00170-2
Abstract
Earth’s crust contains a substantial proportion of global biomass, hosting microbial life up to several kilometers depth. Yet, knowledge of the evolution and extent of life in this environment remains elusive and patchy. Here we present isotopic, molecular and morphological signatures for deep ancient life in vein mineral specimens from mines distributed across the Precambrian Fennoscandian shield. Stable carbon isotopic signatures of calcite indicate microbial methanogenesis. In addition, sulfur isotope variability in pyrite, supported by stable carbon isotopic signatures of methyl-branched fatty acids, suggest subsequent bacterial sulfate reduction. Carbonate geochronology constrains the timing of these processes to the Cenozoic. We suggest that signatures of an ancient deep biosphere and long-term microbial activity are present throughout this shield. We suggest that microbes may have been active in the continental igneous crust over geological timescales, and that subsurface investigations may be valuable in the search for extra-terrestrial life.Funding Information
- Vetenskapsrådet
- Svenska Forskningsrådet Formas
This publication has 85 references indexed in Scilit:
- Anaerobic Oxidation of Methane: Progress with an Unknown ProcessAnnual Review of Microbiology, 2009
- Detecting the near-surface redox front in crystalline bedrock using fracture mineral distribution, geochemistry and U-series disequilibriumApplied Geochemistry, 2009
- Sulfur isotope measurement of sulfate and sulfide by high-resolution MC-ICP-MSChemical Geology, 2008
- The occurrence and potential origin of asphaltite in bedrock fractures, Forsmark, central SwedenGFF, 2006
- Sulfur Isotope Geochemistry of Sulfide MineralsReviews in Mineralogy and Geochemistry, 2006
- Strontium, Neodymium and Lead Isotope Analyses of NIST Glass Certified Reference Materials: SRM 610, 612, 614Geostandards Newsletter, 2001
- Bacterial and thermochemical sulfate reduction in diagenetic settings — old and new insightsSedimentary Geology, 2001
- Exploration of deep intraterrestrial microbial life: current perspectivesFEMS Microbiology Letters, 2000
- 87Sr/86Sr, δ13C and δ18O evolution of Phanerozoic seawaterChemical Geology, 1999
- The Occurrence of Asphaltite and Thucholite in the Precambrian Bedrock of SwedenGeologiska Föreningen i Stockholm Förhandlingar, 1966