Astrobiology and ammonia


While working as a geomicrobiologist within the Planetary and Space Sciences Research Institute (Open University, UK), I became involved in astrobiological research, the primary focus of the geomicrobiology research group at the Open University. The leader of this group (Professor Charles Cockell) has subsequently established a UK Centre for Astrobiology at Edinburgh University. Those involved in geomicrobiology or astrobiology research will recognise that there are intimate links between these two interdisciplinary areas of science.

A short-term contract, funded by the European Space Agency, allowed me to investigate the tolerance of microbes, particularly sporeformers, towards ammonia. Despite its presence on Earth in a variety of habitats, the limits for microbial tolerance were unknown. As ammonia is present in a variety of extraterrestrial habitats (e.g. Enceladus, Titan etc.), and the presence of ammonia significantly lowers the freezing point of water, the possibility of finding life in a liquid ammonia-water environment on extraterrestrial is an interesting question. The first step to answering this question is to determine whether microbes can survive such high concentrations of ammonia found in these extraterrestrial environments. An equally important question is whether terrestrial microbes contaminating spacecraft may survive if transported to such ammonia-rich extraterrestrial environments, thus potentially contaminating those environments.

As sporeformers are the most likely spacecraft contaminants and the most resistant to environmental stress, soil microbes were chosen for laboratory experiments. Exposure to the highest possible concentration of ammonia (35%) revealed a high rate of survival of sporeforming organisms under low temperature conditions. Results also indicated the survival of a comparatively small number of non-sporeforming bacteria. Details of this research have been published in the International Journal of Astrobiology.



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