Microbial Survival and Viability in Saline Environments on Mars (BRINES)

• Applicant: Dr. Jacob Heinz
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455070607

It is still an open question whether microbial life is or has been present on Mars - even 45 years after the performance of the first life detection experiments by the Viking landers on the Red Planet. A better understanding of the planet’s potential habitable environments is needed, to search for life on Mars in the right locations and with the most appropriate analytical tools. In its early history Mars had a warmer and wetter climate than today, however, the loss of its magnetic field and the concomitant depletion of its atmosphere resulted in the formation of a cold and dry desert planet. Life as we know it requires liquid water and, therefore, the investigation of the Martian habitability is connected to the search for environments containing liquid water. One of those potentially habitable niches are cold brines (cryobrines) that can form on Mars via deliquescence, which is the process when a hygroscopic salt absorbs water from the atmosphere and dissolves within that water. There is strong evidence for the occurrence of deliquescence and the (at least temporarily) existence of brines on Mars and in its subsurface. The salts in these brines lower the freezing point of water significantly and, thus, expand the temperature range for the stability of liquid water on Mars substantially. However, not much is known about the microbial habitability of these brines. The objective of this project is to investigate the salt tolerances of various halophilic and halotolerant microorganisms of all three domains of life (bacteria, archaea, and eukaryotes) in brines of several Mars-relevant salts (chlorides, chlorates, perchlorates, sulfates, and nitrates) in dependence of temperature. The metabolic and morphologic stress responses that occur during microbial growth under salt stress conditions will be investigated via microscopic analyses, metabolomics, and proteomics. Additionally, the most halophilic organisms will be exposed to a Mars-like environment (strong UV radiation, low pressures, CO2 atmosphere, drastic changes in temperature and relative humidity) in a Mars simulation chamber, which is available in the lab of the Astrobiology Research Group at the TU Berlin. The objective of these experiments is to investigate whether microbial growth under Mars-like environmental conditions in briny solutions is possible. The results of all experiments described above will be published in international open access journals. This research study will not only enhance our knowledge about the habitability of Mars, but will also provide new insights in the research areas of environmental microbiology, extremophilic organisms, proteomics, metabolomics, and biotechnology.

• DFG Programme: Research Grants