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Nisson DM, Walters CC, Chacón-Patiño ML, Weisbrod CR, Kieft TL, Sherwood Lollar B, Warr O, Castillo J, Perl SM, Cason ED, Freifeld BM, Onstott TC. Radiolytically reworked Archean organic matter in a habitable deep ancient high-temperature brine. Nat Commun 2023; 14:6163. [PMID: 37789019 PMCID: PMC10547683 DOI: 10.1038/s41467-023-41900-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 09/20/2023] [Indexed: 10/05/2023] Open
Abstract
Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101-283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45-55 °C), low biomass (102-104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (-ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3-C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1-C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth.
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Affiliation(s)
- Devan M Nisson
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA.
| | | | | | - Chad R Weisbrod
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Thomas L Kieft
- Department of Biology, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA
| | - Barbara Sherwood Lollar
- Department of Earth Sciences, University of Toronto, Toronto, ON, M5S 3B1, Canada
- Institut de Physique du Globe de Paris (IPGP), Université Paris Cité, 1 rue Jussieu, 75005, Paris, France
| | - Oliver Warr
- Department of Earth Sciences, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Julio Castillo
- Department of Microbiology and Biochemistry, University of the Free State, Bloemfontein, 9300, South Africa
| | - Scott M Perl
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Errol D Cason
- Department of Animal Sciences, University of the Free State, Bloemfontein, 9300, South Africa
| | | | - Tullis C Onstott
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA
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