柴达木盆地蒸发盐中生物分子的保存及天体生物学意义

Martian salts are potential targets for the search for biological signatures on Mars. Evaporites of arid regions on Earth are the most relevant analogues of these Martian evaporative deposits with regard to the search for preserved biosignatures. However, traditional methods such as isolation and culture limit our systematic understanding of the life in salts, and little attention has been paid to the distribution of biological molecules and the reasons for their difference preservation in subsurface ancient evaporites. The abundant evaporites and persistent drought in the Qaidam Basin make it an important window to explore these issues. In this work, subsurface sediments are planned to be sampled from different vertical profiles from the Dalangtan and Qarhan of Qaidam Basin. We plan to examine the concentration and distribution of DNA, lipids and small molecular organic acids preserved in these deposits based on the analysis of sedimentary sequence, mineral composition and chronology. By comparing with the research results of other terrestrial analogies, we will address the distribution of biological molecules and the reasons for their different preservation in evaporites. The biomarkers preserved in the evaporites would provide scientific evidences on potential life on Mars.

火星盐类环境是寻找火星生命信号的潜在目标，地球干旱高盐环境的类比研究是深入了解火星盐类沉积物中生物分子的重要途径。传统分离培养等方法极大地限制了我们对盐类环境生命特征的系统认识，目前对蒸发盐中生物分子保存的研究仍非常初步，控制地质历史时期盐类沉积物中生物分子差异保存的环境因素也不明确。柴达木盆地丰富的蒸发盐沉积和持续的干旱环境使其成为探索以上问题的重要窗口。本研究以柴达木盆地大浪滩和察尔汗蒸发盐沉积剖面为研究对象，在对蒸发盐沉积层序、年代学和矿物组成进行系统分析的基础上，分析关键层位DNA分子、类脂分子及小分子有机酸的保存，并通过与全球其它火星类比点已有研究成果综合对比，全面认识蒸发盐中生物分子的分布规律，明确生物分子在蒸发盐中差异保存的主控因素，从而为认识火星盐类潜在的生命信息提供科学依据。

火星盐类环境是寻找火星生命信号的潜在目标，地球干旱高盐环境的类比研究是深入了解火星盐类沉积物中生物分子的重要途径。本研究以柴达木盆地大浪滩和察尔汗蒸发盐沉积剖面为研究对象，在对蒸发盐沉积层序、年代学和矿物组成进行系统分析的基础上，分析关键层位类脂分子的保存，并通过与全球其它火星类比点已有研究成果综合对比，全面认识蒸发盐中生物分子的分布规律，明确生物分子在蒸发盐中差异保存的主控因素。结果表明， 柴达木盆地盐类样品中包含较为丰富的脂肪酸化合物、甘油二烷基甘油四醚化合物(GDGTs)和古菌醇(archaeol)化合物。微生物来源的类脂物在蒸发盐中存在明显差异分布: 相对低盐的盐类样品中, 脂肪酸的多样性更丰富、 含量更高, GDGTs和archaeol化合物含量高于高盐样品，当沉积物全部由盐类矿物构成时，类脂物的分布明显受到限制。盐类矿物含量是造成类脂物差异分布的主控因素，archaeol化合物是地球高盐沉积物中广泛分布的生物分子。本研究为限定和综合评价火星蒸发盐中可能存在的生命痕迹提供了一种类比模式。

内容获取失败，请点击重试