Artificial maturation of biogenic organic matter

Searching for biochemical traces of life on the surface of Mars

Biomolecules in sedimentary rocks change over time through different stages of diagenesis and metamorphism. In this study both fossil and recent microbial biomass shall be subjected to different environmental conditions over extended periods of time, and molecular changes will be recorded. The goal of this study is to provide reference data on biogenic material in rocks and to support the search for biochemical traces of life in old sedimentary rocks on the surface of Mars. In that respect this project is highly complementary to the alternative PhD project "Formation and characterization of non-biogenic macromolecular organic material".

The starting materials for these investigations will be immature sedimentary organic matter, as well as recent algal and bacterial biomass. These materials will be artificially maturated in an autoclave. The goal of this study is to monitor, and specify, molecular changes (average molecular weight, cross-linking, aromaticity, functional groups, degree of oxidation etc) over a range of P,T–conditions. Different analytical techniques will be used in conjunction, namely gas chromatography-mass spectrometry (GC-MS), (hydro-)pyrolysis GC-MS, laser desorption ionization-MS (LDI), and Raman spectroscopy. Both GC-MS and LDI will be utilized by the German-French-US developed MOMA instrument (Mars Organic Molecule Analyzer) onboard the European/Russian ExoMars-2018 rover to search for organic compounds in Martian sedimentary rocks. Hence the results of this project will support interpretation of MOMA Mars data that are expected early in the next decade.

The candidate is expected to have gained previous experience (through e.g. Bachelor/Master project) in at least one of the following fields: Geochemistry, analytical chemistry, mass spectrometry.

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