Non-Psychrophilic Methanogens Capable of Growth Following Long-Term Extreme Temperature Changes, with Application to Mars

Abstract

Although the martian environment is currently cold and dry, geomorphological features on the surface of the planet indicate relatively recent (<4 My) freeze/thaw episodes. Additionally, the recent detections of near-subsurface ice as well as hydrated salts within recurring slope lineae suggest potentially habitable micro-environments within the martian subsurface. On Earth, microbial communities are often active at sub-freezing temperatures within permafrost, especially within the active layer, which experiences large ranges in temperature. With warming global temperatures, the effect of thawing permafrost communities on the release of greenhouse gases such as carbon dioxide and methane becomes increasingly important. Studies examining the community structure and activity of microbial permafrost communities on Earth can also be related to martian permafrost environments, should life have developed on the planet. Here, two non-psychrophilic methanogens, Methanobacterium formicicum and Methanothermobacter wolfeii, were tested for their ability to survive long-term (~4 year) exposure to freeze/thaw cycles varying in both temperature and duration, with implications both for climate change on Earth and possible life on Mars.

Experimental and Simulation Efforts in the Astrobiological Exploration of Exooceans

“…This is predominately due to the difficultly in simulating the relatively high pressures associated with these environments. For example, when investigating the effect of Mars conditions on microbial growth, experiments are routinely conducted in glass containers (e.g., Schirmack et al 2015;Mickol et al 2018), which are unable to sustain pressures above 1 bar. To alleviate this issue, high pressure reactors are used.…”

Detection of Microorganisms in Low-Temperature Water Environments by in situ Generation of Biogenic Nanoparticles

“…Nevertheless, the development of new effective techniques for the detection of putative life beyond Earth is still an important problem to be solved (Nadeau et al, 2008;Garcia-Descalzo et al, 2012;Judge, 2017;Nelis et al, 2018). The basic astrobiological methods are mostly related to search for biosignatures of a geological, chemical, and biomorphological nature (Cockell, 2010;Westall et al, 2015;Hays et al, 2017;Mickol et al, 2018). Here, we propose a novel nanobiotechnological approach for the detection of microbiological objects in water or melted ice samples from extraterrestrial low-temperature environments.…”

Response of Methanogenic Archaea from Siberian Permafrost and Non-permafrost Environments to Simulated Mars-like Desiccation and the Presence of Perchlorate

“…Ulrich et al (2012) discussed the potential habitability of periglacial landscapes in martian midlatitudes by relating terrestrial analogs to permafrost landforms on Mars. Subsurface permafrost environments on Mars represent potential habitable regions where extant life could have survived (Cockell, 2014;Schirmack et al, 2014); additionally, terrestrial permafrost is considered the most promising analog to a potential martian habitat Mickol et al, 2018). Microbial communities in terrestrial permafrost and coldassociated environments often appear in high density and consist of specialized cold-adapted microorganisms (Wagner, 2008;Bajerski and Wagner, 2013;Mitzscherling et al, 2017).…”

“…Methanogenic archaea from Siberian permafrost meet many of the preconditions for survival in the martian subsurface, showing a remarkable resistance against desiccation, osmotic stress, low temperatures, starvation, radiation, and thermophysical martian conditions as compared to non-permafrost strains Morozova et al, , 2015Morozova et al, 2015;Mickol et al, 2017). They are also a subject of astrobiological interest for future planetary exploration missions that involve life detection (de Vera et al, 2012;Serrano et al, 2014Serrano et al, , 2015Mickol et al, 2018;Taubner et al, 2018). Schuerger et al (2012) discussed the biotoxicity of multiple martian soils and concluded that they are not likely to be overtly toxic to terrestrial microorganisms.…”