Fatty Acid Recovery and Identification in Mars Analogue Soil Samples

Abstract

A primary goal of NASA’s Mars 2020 mission is to gather and store samples of Mars soil that could possibly be returned to Earth in a future mission for investigations into past or present life. In years leading up to a potential sample return mission on Mars and potentially other worlds, samples taken from Chile’s Atacama Desert, the most arid, biologically limited desert in the world, are valuable in developing a capacity for biosignature detection, specifically when exploring fatty acid abundance. Eighteen samples were collected from two sites in the Atacama characterized by biological soil crusts (BSC). BSCs are areas of the desert where photosynthetic bacteria and simple plants live within the uppermost portion of the desert floor. Soil samples from each site were processed in a Total Fatty Acid (TFA) lab procedure as described by Graber and Tsechansky (2009) and analyzed by using gas chromatography (GC). The resulting GC chromatograms were analyzed for the presence and abundance of various types of fatty acids, a family of organic molecules necessary for metabolism and the formation of cell membranes. Further analysis of these fatty acids and possible identification of the host microorganisms will be investigated in an effort to reconstruct the composition and history of BSC. Ultimately, the results of this study further understanding of present fatty acids in the Atacama’s microbial life; thus, granting insight into biosignatures that might reveal the presence of living organisms capable of sustaining biological processes in extreme, Mars-like climatic conditions