Mars analogue sites

Extreme terrestrial environments are excellent models to study the limits of life, and to infer habitability of extraterrestrial settings. Different to potential extraterrestrial biotopes, however, Earth's ecosystem unavoidably contains oxygen, substantially shaping the microbial ecosystem. Herein, we report on the microbiological comparison of five types of anoxic environments, resembling selected Early and nowadays Martian settings. We assessed the living microbiomes by propidium monoazide 16S rRNA gene amplicon and metagenome sequencing, and by a wide-scale cultivation approach, in which 1034 anaerobic enrichments were processed. We identified an extremotolerant cosmopolitan group of 34 different taxa, thriving in all sites studied, and a similar functional profile in all sites, indicating a general principle of adaptation of anaerobic microbial communities to extreme conditions.Our efforts resulted in the cultivation of 69 mixed cultures and 31 bacterial (30) and archaeal (1) model isolates. On microbiome level, temperature was found to influence the microbial community most, and acidic environments clustered with hypersaline environment samples, indicating a potential general principle. Beyond, we uncovered a physiologically adapted bacteriome and archaeome, and a Sixty-nine microbial enrichments and 31 isolates were obtained from the MASE sites