Weber Jessica M, Marlin Theresa C, Prakash Medha, Teece Bronwyn L, Dzurilla Katherine, Barge Laura M
NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
Life (Basel). 2023 Aug 11;13(8):1726. doi: 10.3390/life13081726.
Enceladus and Europa, icy moons of Saturn and Jupiter, respectively, are believed to be habitable with liquid water oceans and therefore are of interest for future life detection missions and mission concepts. With the limited data from missions to these moons, many studies have sought to better constrain these conditions. With these constraints, researchers have, based on modeling and experimental studies, hypothesized a number of possible metabolisms that could exist on Europa and Enceladus if these worlds host life. The most often hypothesized metabolisms are methanogenesis for Enceladus and methane oxidation/sulfate reduction on Europa. Here, we outline, review, and compare the best estimated conditions of each moon's ocean. We then discuss the hypothetical metabolisms that have been suggested to be present on these moons, based on laboratory studies and Earth analogs. We also detail different detection methods that could be used to detect these hypothetical metabolic reactions and make recommendations for future research and considerations for future missions.
土卫二和木卫二分别是土星和木星的冰卫星，据信它们拥有液态水海洋，具备宜居条件，因此对未来的生命探测任务和任务概念具有重要意义。鉴于前往这些卫星执行任务所获取的数据有限，许多研究致力于更好地界定这些条件。基于这些限制条件，研究人员通过建模和实验研究，推测出如果木卫二和土卫二存在生命，可能存在的多种代谢方式。最常被推测的代谢方式是土卫二上的甲烷生成以及木卫二上的甲烷氧化/硫酸盐还原。在此，我们概述、回顾并比较了每个卫星海洋的最佳估计条件。然后，我们基于实验室研究和地球类似环境，讨论了这些卫星上可能存在的假设代谢方式。我们还详细介绍了可用于检测这些假设代谢反应的不同检测方法，并为未来研究提出建议以及对未来任务的考量。
