论文标题：The Fate of Lipid Biosignatures in a Mars-Analogue Sulfur Stream

期刊：Scientific Reports

作者：Jonathan Tan, James M. T. Lewis & Mark A. Sephton

发表时间：2018/05/15

数字识别码：10.1038/s41598-018-25752-7

原文链接：http://www.nature.com/articles/s41598-018-25752-7?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-Nature-Scientific_Reports-Earth_Sciences-China&utm_campaign=SCIREP_USG_JRCN_RL_Mars_sciencenet_article_3rd_July

《科学报告》发表的一项研究The Fate of Lipid Biosignatures in a Mars-Analogue Sulfur Stream探究了在类比火星环境的酸性流中嗜酸生物的有机反应。

在火星上生存过的生物会产生有机残留物，这些残留物可能被保存在火星岩石中。在火星历史上保留有大面积地表水的最近的一个时期是在晚诺亚纪和早赫斯伯利亚纪之间，水的存在使得火星在这段时期可以维持进化程度较高且分布广泛的火星生命。通过对地球上类酸性和高硫环境的研究，可以为探究晚诺亚纪和早赫斯伯利亚纪时期的岩石提供指导。来自英国帝国理工学院的James M. T. Lewis及其同事，报道了在含有嗜酸生物的酸性流中的有机反应，这些嗜酸生物死后的残骸被埋在硫酸铁和氧化铁中。研究人员发现，如果赫斯伯利亚纪时期有生命存在，火星上有机物质的记录将包括微生物脂质。脂质在火星上是一个潜在的且巨大的化石碳储藏库，可以用来区分不同领域的生命。脂质的浓度，尤其是链烷酸或脂肪酸，在针铁矿层含量最高，这反映出岩石中较高的含水比例，因此具有较高的可居住性。在火星上，针铁矿普遍可以脱水转化为赤铁矿。未来，火星探测的任务应该是在高硫环境下铁的氧化物和氢氧化物中检测脂肪酸或者其成岩产物。

摘要：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.

阅读论文全文请访问：http://www.nature.com/articles/s41598-018-25752-7?utm_source=Other_website&utm_medium=Website_links&utm_content=RenLi-Nature-Scientific_Reports-Earth_Sciences-China&utm_campaign=SCIREP_USG_JRCN_RL_Mars_sciencenet_article_3rd_July

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（来源：科学网）