Remote Sensing of Microorganisms

This PhD project will investigate the impact of icy-moon environmental conditions on the detectability of selected bacteria in ice/salt mixtures rapidly exposed to vacuum, extremely low temperatures and high-radiation levels. For this purpose, a high-sensitivity spectro-polarimeter will be interfaced with a temperature-vacuum chamber. Additionally, an electron gun and a UV light source will be used to investigate the incidence of harsh conditions on bacterial samples deposited on ice as a proxy for icy moon conditions. The study will also investigate whether spectro-polarimetry could probe fundamental structures in the microorganisms such as cofactors or proteins in the near UV. The project will thus investigate the detectability of fundamental biosignatures relevant to a wider range of microorganisms. This effort will inform the preparation of future life-detection missions in our Solar System, such as the planned ESA L4 mission to Enceladus.

The successful candidate will join an interdisciplinary team (lead: Prof. Brice-Olivier Demory) with expertise spanning astrophysics, microbiology, biomedicine and engineering. The new group member will have the opportunity to gain unique experience in dual-use instrumentation applicable to both space exploration and medical diagnostics.

This PhD project will investigate for the first time the combination of remote life sensing techniques using circular spectro-polarimetry with in situ laser-based mass spectrometry measurements, both designed for the detection or signatures of life. The work will mainly involve experiments in the lab, using cell cultures of a range of strains (including anaerobic cultivation of microorganisms) and various classes of organic molecules relevant to Solar System environments. These studies will be complemented by targeted field measurements of soil material containing microorganisms and low abundant organics that are relevant candidates for extinct/extant life on Mars or in the icy moons of the solar system. The results of this endeavour will reveal the potential of combining life detection methods at different scales that will be key to define optimal strategies for future life-detection missions, such as the planned ESA L4 mission to Enceladus or future NASA mission to Mars.

The successful candidate will join an interdisciplinary team with expertise spanning astrophysics, microbiology, biomedicine and engineering. The new group member will have the opportunity to gain unique experience in dual-use instrumentation applicable to both space exploration and medical diagnostics.

This PhD position is also affiliated with the project "In situ detection of organics" led by PD Dr. Andreas Riedo, who will jointly supervise the PhD student with Prof. Dr. Brice-Olivier Demory.