Bio)mineralogy for planetary sciences – My research has since its beginning been focused on the application of mineralogy (i.e. the study of naturally occuring solids, of their genesis and of their interactions with their environment) and mineral physics (condensed matter physics applied to mineralogy) to important (at least in my eyes) problems of Earth and planetary sciences.
High-pressure mineralogy of planetary interiors – My research background has been built on the study of mineralogy and properties of deep Earth. Under the impulsion of Dr Jean-Paul Poirier, I mostly applied transmission electron microscopy to the study of high-pressure diamond-anvil cell samples, then a pioneering approach, and derived from these data properties and models of the Earth lower mantle. Motivated by the discovery of thousands of exoplanets, I am still pursuing in that field of research in main collaboration with Guillaume Fiquet (ERC advanced grant PLANETDIVE).
Biomineralization by prokaryotic microorganisms– In close collaboration with Philippe Gillet (then at ENS Lyon, France, now at EPFL, Lausanne, Switzerland) and with Karim Benzerara (then PhD student at IMPMC, now research director at IMPMC, Paris), I started to apply the very same mineral physics concepts as those used in planetology to the study of biomineralization by prokaryotic microorganisms. This was initially done in the context of finding traces of life in extreme environments with possible applications to Mars sample returns and to extra-terrestrial samples. In the recent years, I have pursued research on biomineralization mainly on iron oxides and applications of magnetotactic bacteria in collaboration with Edouard Alphandéry (IMPMC Paris and the startup Nanobacterie), Jennyfer Miot (then PhD student at IMPMC, now researcher at IMPMC Paris), and recently Zoher Gueroui (ENS Paris). I also have participated to researches about phosphate biomineralization by bacteria in collaboration with Julie Cosmidis (then PhD student at IPG/IMPMC Paris) and Karim Benzerara (IMPMC, Paris). In this field, I have initiated geochemical work on magnetotactic bacteria with Matthieu Amor (then PhD student IMPMC Paris now at UC Berkeley with Pr Arash Komeili) and Vincent Busigny (IPG Paris). I am still participating into this research with the aim of better modeling the elemental and isotope compositions of magnetites and greigites in microbial cultures and in the environment.
Environmental biomineralogy – I have also applied the concepts of mineralogy, biomineralization and mineral physics to environmental studies, mostly focused on fundamental and applied issues in CO2 capture, storage and valorization, in collaboration with Bénédicte Menez (IPG Paris) in the framework of the IPG, Total, Schlumberger CO2 center in Paris. This drove researches on fundamental processes at the mineral water interface that I am pursuing with Damien Daval (then PhD student at IPG Paris and ENS Paris, now researcher at LHYGES Université de Strasbourg). The new issue of finding ways of valorizing CO2 being inspired by natural processes, especially with regard of H2 generation and CO2-H2 interactions, has led me to collaborate with several researchers, mainly Isabelle Martinez (IPG Paris), Vincent Milesi (then PhD student IPG Paris now at Total), Fabrice Brunet (IsTerre, Université de Grenoble, France), and colleagues at IFPEN in Rueil, France (Virgile Rouchon, Laura Créon then PhD student, Valérie Beaumont, Eric Deville, Julia Guelard PhD student, Christele Vacquand then PhD student, Olivier Sissmann, Alain Prinzhofer). The CO2 and H2 problematics both require strong geochemical modeling. I have an ongoing collaboration regarding applications of the Chess Code with Jérôme Corvisier and Laurent de Windt (Ecole des Mines de Paris, Fontainebleau) and modeling of stable isotope fractionations by subsurface biomass with Magali Ader (IPG Paris), Bénédicte Ménez (IPG Paris), Caroline Thaler (then PhD at IPG Paris now at MNHN Paris) and Giovanni Aloisi (CNRS, UPMC, Paris). Some ab initio modeling of CO2 and H2 reactivity at mineral surfaces are also required to investigate the difficult question of specific properties in aqueous solutions at the vicinity of mineral surfaces. I participate to this latter research lead by Marco Saitta and Fabio Pietrucci (IMPMC, Paris).
Hydrothermal biomineralization – In the years coming, I would like to focus on one single research projet in which I wish to apply the multiple skills acquired and mentioned above. This new project is entitled : « Biomineralization in Hydrothermal Conditions by Hyperthermophilic Microoganisms ». It has fundamental ambitions such as to determine whether mineral traces of biological activity at high pressure and temperature in hydrothermal systems can actually be identified with important implications for finding new traces of life in the rock record and for the search of auto-organization phenomena in terrestrial and extra-terrestrial samples. It also aims at determining whether mineral phases can inform us about the biodiversity in the hottest parts of these hydrothermal systems, present and past, at investigating the questions of adaptation of life to extreme temperatures and at understanding the mechanistic and ecological meanings of the high temperature limits of life. It also has potential applications such as possible improvement of hydrothermal synthesis of solids by assistance of hyperthermophilic organisms or gains in bioleaching industrial processes by using hyperthermophilic microorganims. This project will strongly benefit from the proximity of researchers pursuing their own projects at Muséum National d’Histoire Naturelle, particularly Sylvain Bernard (IMPMC, Paris), Adrienne Kish (MCAM, Paris), Jennyfer Miot (IMPMC, Paris) and Laurent Rémusat (IMPMC, Paris). It will also benefit from appreciated assistance in knowledge of hyperthermophilic organisms by Aurore Gorlas (Université Paris Sud) and Erwan Roussel (IFREMER Brest).