Periodic Reporting for period 2 - BIOMAMA (Biogenicity of Martian Materials: critical assessment of biosignatures based on chemolithoautotrophic interactions)
Periodo di rendicontazione: 2023-11-01 al 2025-04-30
The search for biologically driven alterations on Mars and its potential as habitat for past or present life is a primary aim of the ongoing and upcoming Mars exploration missions. While a range of environments that would have been well suited to support a potential chemolithotrophy on Mars have been proposed, our understanding of putative biosignatures to be targeted in Martian materials is still elusive. A valuable source of information can be extracted from microbial fingerprints of chemolithotrophic life based on Martian materials (e.g. Martian meteorites). The project BIOMAMA investigates Mars-relevant biosignatures of microbial chemolithotrophic life based on Martian genuine meteorites. Chemolithotrophic microorganisms employ an astonishing number of metabolic pathways to extract energy from diverse inorganic electron donors/acceptors, shaping global biogeochemical cycles. We perform the bottom-up exploration of mineral-microbial interactions for different chemolithotrophs cultivated on Martian mineral materials as the sole energy sources. The project explores unique microbial interactions with extraterrestrial materials down to the nanoscale and atomic resolution utilizing a comprehensive toolbox of cutting-edge techniques. We identify preservable biomarkers/biosignatures of chemolithotrophic life on Martian materials after the exposure to simulated Martian conditions at low Earth orbit and ground-based facilities. The project aims to decipher Mars-relevant mineral and metabolic biosignatures.
Currently the route to understanding our biological heritage is by no means clear-cut or straightforward. Nevertheless, defining the biogeochemical patterns/processes through which life can exists beyond Earth would undoubtedly have a significant and lasting impact upon society in general. “Is our Earth the only hotbed of life in the Universe and how to find this out?”- mankind reflections inherent to this question have been raised and discussed on various levels within many centuries. Assessing the biogenicity based on Martian materials (the priority of BIOMAMA project) is a critical analytical step on this way. The project results will provide scientific knowledge for the detection of biosignatures implementing in life search missions. Such investigations may deliver a guiding point for in-situ measurements to analyze collected Mars samples. By furthering our knowledge of the life based on Martian materials, investigation of meteorite-microbial interactions is directly relevant to defining the habitability of extraterrestrial environments, planetary protection and space crew health protection issues. The project will promote wider social implications of discovering of life across the Universe. Fundamentally this would necessitate addressing the ethical, scientific and religious challenges ahead of us. Scientifically, understanding how biological life can exist beyond Earth and which stable and detectable traces it leaves would have great significance for environmental affairs.
Currently the route to understanding our biological heritage is by no means clear-cut or straightforward. Nevertheless, defining the biogeochemical patterns/processes through which life can exists beyond Earth would undoubtedly have a significant and lasting impact upon society in general. “Is our Earth the only hotbed of life in the Universe and how to find this out?”- mankind reflections inherent to this question have been raised and discussed on various levels within many centuries. Assessing the biogenicity based on Martian materials (the priority of BIOMAMA project) is a critical analytical step on this way. The project results will provide scientific knowledge for the detection of biosignatures implementing in life search missions. Such investigations may deliver a guiding point for in-situ measurements to analyze collected Mars samples. By furthering our knowledge of the life based on Martian materials, investigation of meteorite-microbial interactions is directly relevant to defining the habitability of extraterrestrial environments, planetary protection and space crew health protection issues. The project will promote wider social implications of discovering of life across the Universe. Fundamentally this would necessitate addressing the ethical, scientific and religious challenges ahead of us. Scientifically, understanding how biological life can exist beyond Earth and which stable and detectable traces it leaves would have great significance for environmental affairs.
The project investigates microbial Mars-relevant biosignatures based on Martian genuine meteorites, their preservation and life survival under Mars-like conditions. In line with the objectives of Research Topic 1, we have been performing the characterisation of microbial physiology and mineral-microbial interfaces of chemolithoautotrophs grown on Mars relevant materials. Microbial interactions with Mars relevant minerals are investigated with spectroscopy techniques and their microbial-mineral interfaces have been prepared for subsequent nano-analysis via transmission electron microscopy and synchrotron based techniques to achieve the objectives of Research Topic 2. In frames of the objectives of Research Topic 3, we have developed an improved protocol for metabolite extraction and identification of respiratory quinones in extremophilic Archaea grown on mineral materials. Owing to their durability and stability over geological timescales, these thiophene-bearing quinones have been proposed as biomarkers for astrobiological life detection in extreme environmental conditions on Earth and Mars. Microbial life survival and microbial fingerprints under Mars-like conditions have also been investigated in the project (Research Topic 4). The existence and molecular traces of thermophiles in cold Mars-relevant environments have recently been reviewed in our team in terms of astrobiology and the search for extraterrestrial life (Milojevic et al., 2022). In this paper we highlighted potential of chemolithotrophic thermophilic life and its preservation in cold Mars environment. This work has expanded our understanding of how and through what molecular and physiological mechanisms, rock-processing thermophiles can survive in Mars psychrobiotic environments, which is essential in aiding the search for past, or extant life, on other planets, such as Mars. Most importantly, we have already exposed the microbial-martian meteorite samples to Mars-like conditions outside the ISS. The work on the preservation of Mars-relevant biosignatures in these ISS returned samples is currently in progress in our team (Research Topic 4). Furthermore, microbial-mineral interfaces naturally occurring in Martian analogue sites, have been currently investigated within the project (Research Topic 5). This approach will help reveal novel microbial species that live on the account of Mars analogues minerals at the edge of living limits and detect the preserved organic material and biomineral assemblages associated with Mars analogue environments that could serve as potential biosignatures. Project’s results obtained within the first reporting period have been intensively presented at several European and worldwide conferences as talks and posters. The work performed within BIOMAMA project has been accumulated and presented in several manuscripts which are currently at different stages of the peer review process (published, in review, revision and under the submission).
The extensive knowledge gained from BIOMAMA project will help to understand and critically interpret the results of ongoing and future Mars exploration missions (Mars 2020, ExoMars). Investigations within the project demonstrated the survival of microbial life, encapsulated in minerals, during interplanetary transfer under Mars mimicking conditions outside the ISS, providing the lithopanspermia theory with evidence at the subcellular level. Our research will lay the foundation for efficient nanoanalytical spectroscopy of returned Mars samples to critically assess their potential biogenicity.