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Sulfur isotopes as biosignatures for Mars and Europa exploration
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dc.contributor.author | Moreras-Marti, A. | |
dc.contributor.author | Fox-Powell, M. | |
dc.contributor.author | Cousins, C. R. | |
dc.contributor.author | Macey, M. C. | |
dc.contributor.author | Zerkle, A.L. | |
dc.date.accessioned | 2022-08-26T16:30:05Z | |
dc.date.available | 2022-08-26T16:30:05Z | |
dc.date.issued | 2022-11-04 | |
dc.identifier | 280180357 | |
dc.identifier | 01fe16c5-7e4b-4cb7-9741-bc383f524a0c | |
dc.identifier | 000868437100001 | |
dc.identifier | 85142282503 | |
dc.identifier.citation | Moreras-Marti , A , Fox-Powell , M , Cousins , C R , Macey , M C & Zerkle , A L 2022 , ' Sulfur isotopes as biosignatures for Mars and Europa exploration ' , Journal of the Geological Society , vol. 79 , no. 6 , jgs2021-134 . https://doi.org/10.1144/jgs2021-134 | en |
dc.identifier.issn | 0016-7649 | |
dc.identifier.other | Jisc: 392387 | |
dc.identifier.uri | https://hdl.handle.net/10023/25898 | |
dc.description | Funding: This work was funded by the Leverhulme Trust (RPG-2019-353) and UK Space Agency (ST/P001270/1) [C. Cousins and A. Zerkle]. | en |
dc.description.abstract | Sulfur (S) isotopes are used to trace metabolic pathways associated with biological S-cycling in past and present environments on Earth. These pathways (sulfate reduction, sulfur disproportionation, and sulfide oxidation) can produce unique S isotope signals that provide insight into biogeochemical S-cycling. The S cycle is also relevant for extraterrestrial environments and processes. On early Mars, sulfur existed in different redox states and was involved in a large range of surface processes (e.g., volcanic, atmospheric, hydrothermal, and aqueous brines). Sulfur compounds have also been detected on Europa's icy moon surface, with the S cycle implicated in Europa's surface and ocean geochemistry. Given the well-established utility of S isotopes in providing a record for past life on Earth, S isotopes are an valuable tool for identifying biosignatures on Mars and Europa. Here, we review S isotopes as a biosignature, in light of two recent advances in understanding the S cycle in both Mars and Europa: (i) the measurements of δ34S in situ at Gale Crater and quadruple S isotopes (QSI) in Martian meteorites, and (ii) the identification of a likely exogenous origin of sulfur on Europa's surface. We discuss important considerations for unravelling QSI biosignatures in Martian environments, considering high and low sulfur environments, atmospheric S-MIF signals, and metabolic energy-limited niches. For Europa, we describe the potential for S isotopes to probe biogeochemistry, and identify key knowledge gaps to be addressed in order to unlock S isotopic tools for future life detection efforts. The resulting picture demonstrates how S isotopes will be a valuable tool for Mars Sample Return, and how future missions can focus on the search for environments where QSI signatures of microbial S-cycling processes have a greater chance of being preserved. For Europa, the first step will be to account for the S isotope composition of the various S pools, to recognise or rule out non-biologically mediated S isotope values, with a focus on experimental examination of potential S isotope signatures from exogenous sulfur sources. | |
dc.format.extent | 15 | |
dc.format.extent | 2472869 | |
dc.language.iso | eng | |
dc.relation.ispartof | Journal of the Geological Society | en |
dc.subject | QB Astronomy | en |
dc.subject | QE Geology | en |
dc.subject | T-NDAS | en |
dc.subject | MCC | en |
dc.subject.lcc | QB | en |
dc.subject.lcc | QE | en |
dc.title | Sulfur isotopes as biosignatures for Mars and Europa exploration | en |
dc.type | Journal item | en |
dc.contributor.sponsor | The Leverhulme Trust | en |
dc.contributor.sponsor | Science & Technology Facilities Council | en |
dc.contributor.institution | University of St Andrews. St Andrews Centre for Exoplanet Science | en |
dc.contributor.institution | University of St Andrews. School of Earth & Environmental Sciences | en |
dc.contributor.institution | University of St Andrews. Earth and Environmental Sciences | en |
dc.contributor.institution | University of St Andrews. St Andrews Isotope Geochemistry | en |
dc.identifier.doi | 10.1144/jgs2021-134 | |
dc.description.status | Peer reviewed | en |
dc.identifier.grantnumber | RPG-2019-353 | en |
dc.identifier.grantnumber | ST/P001270/1 | en |
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