THLAIJEH Siveen: Characterization of organic matter by laser desorption-mass spectrometry (LDMS): application to primitive life and the search for life on Mars.
Thesis Summary: The goal of this thesis is to apply laser desorption coupled with mass spectrometry (LDMS) techniques with a high-resolution, high resolution mass instrument to characterize current and fossil biomasses. The data thus generated can be compared to those produced by the LDMS instrument that will be shipped by the European robot that will explore Mars in 2021 to look for any traces of current and / or fossil life in the soil. The spectra obtained by LDMS on natural material are complex to interpret because of interferences between minerals and organic structures. A database of reference objects is therefore indispensable for the interpretation of data obtained in situ on Mars. Our new LDMS also has extreme sensitivity and high mass resolution that will allow a thorough identification of the analyzed molecules. The interpretation of LDMS signals recorded with an instrument of lower spectral resolution on Mars will therefore be facilitated by comparison with our data. In parallel, the molecular signatures of different classes of fossil organisms will be compared. We will analyze an exceptional collection of fossils that include some of the first photosynthetic bacteria, early algae, and the first plants on Earth. The goal is to use molecular taxonomy to characterize different problematic old micro / macrofossils. We thus hope, for the first time, from molecular microanalyses of fossilized macro-organisms and micro-organisms, to better constrain key stages in the evolution of primitive life between 3.5 billion and 400 million years before our era.
THLAIJEH Siveen - siveen.thlaijehuniv-lille fr
Thesis supervisor: FOCSA Cristian
Co-supervisors: CARPENTIER Yvain and LEPOT K. (LOG)