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The fate of lipid biosignatures in a Mars-analogue sulfur stream.

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Title: The fate of lipid biosignatures in a Mars-analogue sulfur stream.
Authors: Tan, J
Lewis, JMT
Sephton, MA
Item Type: Journal Article
Abstract: Past life on Mars will have generated organic remains that may be preserved in present day Mars rocks. The most recent period in the history of Mars that retained widespread surface waters was the late Noachian and early Hesperian and thus possessed the potential to sustain the most evolved and widely distributed martian life. Guidance for investigating late Noachian and early Hesperian rocks is provided by studies of analogous acidic and sulfur-rich environments on Earth. Here we report organic responses for an acid stream containing acidophilic organisms whose post-mortem remains are entombed in iron sulphates and iron oxides. We find that, if life was present in the Hesperian, martian organic records will comprise microbial lipids. Lipids are a potential sizeable reservoir of fossil carbon on Mars, and can be used to distinguish between different domains of life. Concentrations of lipids, and particularly alkanoic or “fatty” acids, are highest in goethite layers that reflect high water-to-rock ratios and thus a greater potential for habitability. Goethite can dehydrate to hematite, which is widespread on Mars. Mars missions should seek to detect fatty acids or their diagenetic products in the oxides and hydroxides of iron associated with sulphur-rich environments.
Issue Date: 15-May-2018
Date of Acceptance: 18-Apr-2018
URI: http://hdl.handle.net/10044/1/59227
DOI: https://dx.doi.org/10.1038/s41598-018-25752-7
ISSN: 2045-2322
Publisher: Nature Publishing Group
Start Page: 7586
End Page: 7586
Journal / Book Title: Scientific Reports
Volume: 8
Copyright Statement: © 2018 The Author(s). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Te images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST/N000560/1
Publication Status: Published
Article Number: 7586
Online Publication Date: 2018-09-01
Appears in Collections:Earth Science and Engineering
Faculty of Engineering