Understanding the Potential Role of Oxychlorines in Destroying or Altering Chemical Biosignatures on Mars
Analytical Chemistry
Organic Molecular Chemistry - Synthesis and Characterisation
Final Report Abstract
The investigation to understand the role of oxychlorines in altering and destroying chemical biosignatures included laboratory work with a Mars Simulation Chamber and field work in the Atacama Desert in Chile. The amino acid alanine and the biomolecules ATP, RNA, and chlorophyll were analyzed as chemical biosignatures. In addition, we screened for the presence of metabolites to assess what remained left if cyanobacteria are treated to environmental stresses similar to those on Mars. The biomarkers were incorporated into a variety of geological media and different salts with emphasis on sodium perchlorate to record which combination was most suitable for preservation. While alanine and RNA degraded too fast to get any meaningful results, ATP and metabolites were shown to be good biomolecules to be monitored and still to be detected after a substantial time period. Chlorophyll also degraded very fast, but after several trials we found an instrumental set-up that was able to detect the break-down products of chlorophyll in Mars soil simulant medium, even after exposure of 9 months in the Atacama Desert. In general, preservation of the tested biomolecules was best in quartz sand or Mars soil simulant, followed by quartz sand with sodium chloride. The least preservation was observed in various geological media with sodium perchlorate, in both lab and field tests. Salts with calcium and magnesium were even less suitable, based on simulated Recurrent Slope Lineae and sampled deposits of calcium and magnesium chloride in the Atacama Desert. UV irradiation, in particular, was shown to increase the concentration of oxychlorines in samples, both in the laboratory and the field. The study will inform missions conducted by ESA which molecules to search for in Martian environments to assess whether life has been present on Mars or may even still be present today.
Publications
-
Habitability of nitrate-rich salt crusts in the hyperarid Atacama Desert, Chile. German Astrobiology Society Workshop (DAbG), Essen, Germany, 27-29 Sept. 2021.
Arens, F.L., Airo, A., Sager, C., Schiperski, F., Neumann, T., Pannekens, M., Meckenstock, R., Zoccarato, L., Grossart, H.-P., Valenzuela, B., Zamorana, P. & Schulze-Makuch, D.
-
Understanding the potential role of oxychlorines in altering chemical biosignatures on Mars. German Astrobiology Society Workshop (DAbG), Bremen, Germany, 5-7 September 2022.
Arens, F.L., Naz, N., Kounaves, S. & Schulze-Makuch, D.
-
Salts as proxies for water-soil interaction in the hyperarid Atacama Desert, GeoBerlin, Berlin, Germany, 3-7 September 2023.
Arens, F.L., C. Sager, A. Airo, J. Feige, U. Wiechert & D. Schulze-Makuch
-
The hyperarid Atacama Desert, the ordinary terrestrial standard? CELS Conference Copenhagen, Denmark, 27 July – 3 Aug 2024.
Arens, F., Heinz, J. & Schulze-Makuch, D.
