Abstract

Enceladus is an attractive place to look for signs of life thanks to liquid water and the availability of energy. Recent research has proven that the ejected material of Enceladus south pole consists of water vapor, water ice, carbon dioxide, methane and molecular hydrogen. Possible similarities of physical and chemical conditions between Enceladus ocean bottom and the carbonate mineral matrix of actively venting chimneys of the Lost City Hydrothermal Field give an opportunity to create a mathematical model of microbial ascent process through the ice shell. In this study we present first results of particle in-cell kinetic simulations of microbial distance through 10 km deep ocean. We have obtained results for microbial component—Methanosarcinales sp. analogue—characterized by 6.6 pg mass and 2.0 μm diameter distribution in Enceladus plumes. We have assumed 0.1 W m⁻² heating process, 5 km ice shell and cells concentration near ocean bottom 10⁵ cells/mL. We have confirmed assumption of Porco research team about cells concentration near ocean surface about 10⁴ cells/mL and vertical density diversity in plumes. We have found that the optimal altitude for microbial component detection is less than 1.0 km and that in-situ measurements done previously by Cassini mass spectrometer and proposed for Enceladus Orbiter mission 50 km altitude would be ineffective.

中文翻译：

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土卫二降雪现象中的微生物成分检测

摘要

由于液态水和能源的供应，土卫二是寻找生命迹象的迷人之地。最近的研究证明，土卫二南极喷出的物质包括水蒸气，水冰，二氧化碳，甲烷和分子氢。土卫二海底和失落城市热液场主动排放的烟囱的碳酸盐矿物基质之间的物理和化学条件可能相似，这为建立通过冰壳的微生物上升过程的数学模型提供了机会。在这项研究中，我们提出了通过10 km深海的微生物距离的粒子内动力学模拟的第一个结果。我们已经获得了微生物成分甲烷菌的结果sp。类似物-在土卫二羽中以6.6 pg质量和2.0μm直径分布为特征。我们假设加热过程为0.1 W m ^-2，冰壳为5 km，海底附近的细胞浓度为10 ⁵细胞/ mL。我们已经证实了Porco研究小组关于海洋表面附近细胞浓度约为10 ⁴细胞/ mL以及羽状细胞垂直密度多样性的假设。我们已经发现，用于微生物成分检测的最佳高度小于1.0 km，并且以前由Cassini质谱仪完成并针对Enceladus Orbiter任务建议的50 km高度的原位测量将无效。