School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
Physical Research Laboratory, Ahmedabad, India.
Astrobiology. 2022 May;22(5):579-597. doi: 10.1089/ast.2021.0013. Epub 2022 Feb 15.
Life is known to adapt in accordance with its surrounding environment and sustainable resources available to it. Since harsh conditions would have precluded any possible aerobic evolution of life at the martian surface, it is plausible that martian life, should it exist, would have evolved in such a way as to derive energy from more optimum resources. Iron is one of the most abundant elements present in the martian crust and occurs at about twice the amount present on Earth. Clay minerals contribute to about half the iron found in soils and sediments. On Earth, clay acts as an electron donor as well as an acceptor in the carbon cycles and thereby supports a wide variety of metabolic reactions. In this context, we consider the potential of Fe/Mg smectites, one of the most widely reported hydrated minerals on Mars, for preservation of macro- and microscopic biosignatures. We proceed by understanding the environmental conditions during the formation of smectites and various microbes and metabolic processes associated with them as indicated in Earth-based studies. We also explore the possibility of biosignatures and their identification within the Mars 2020 landing site (Jezero Crater) by using the astrobiological payloads on board the Perseverance rover.
生命据知会根据其周围环境和可利用的可持续资源进行适应。由于恶劣的条件会排除火星表面任何可能的有氧生命进化，因此，如果火星上存在生命，它很可能会进化为从更优质的资源中获取能量。铁是火星地壳中最丰富的元素之一，其含量大约是地球上的两倍。粘土矿物约占土壤和沉积物中铁含量的一半。在地球上，粘土在碳循环中既是电子供体又是电子受体，从而支持了各种各样的代谢反应。在这种情况下，我们考虑了 Fe/Mg 蒙脱石（火星上最广泛报道的水合矿物之一）在保存宏观和微观生物特征方面的潜力。我们通过了解在地球研究中表明的蒙脱石形成期间的环境条件以及与它们相关的各种微生物和代谢过程来进行研究。我们还通过使用毅力号火星车上的天体生物学有效载荷，探索在火星 2020 着陆点（杰泽罗陨石坑）内存在生物特征及其识别的可能性。
