Research Project: Microbial Survival and Viability in Saline Environments on Mars (BRINES)
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 salt solutions (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 salts occurring on Mars (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, proteomics, and other appropriate analytical tools. 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. The goal of these experiments is to investigate whether microbial growth under Mars-like environmental conditions in briny solutions is possible or not. 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.
Funding agency: Deutsche Forschungsgesellschaft DFG (Eigene Stelle, #455070607)
Project members: Jacob Heinz, Anne Gries, Florian Carlo Fischer, and Lea Kloss (Universität Leipzig)
Former members: Vita Rambags (Maastricht University, NL)
Duration: Jan 2021 – Dec 2023
J. Heinz, J. Doellinger, D. Maus, A. Schneider, P. Lasch, H.-P. Grossart, and D. Schulze-Makuch (2022) Perchlorate-Specific Proteomic Stress Responses of Debaryomyces hansenii Could Enable Microbial Survival in Martian Brines. Environmental Microbiology, doi: 10.1111/1462-2920.16152.
J. Heinz, V. Rambags, D. Schulze-Makuch (2021) Physicochemical Parameters Limiting Growth of Debaryomyces hansenii in Solutions of Hygroscopic Compounds and Their Effects on the Habitability of Martian Brines. Life, 11 (1194), doi:10.3390/life11111194.