Geomicrobiology, Biogeochemistry, Microscopy, Spectroscopy
My research investigates the properties of microbe-mineral interactions in the context of biogeochemistry and astrobiology. The focus is on understanding the formation of iron-sulfide (Fe-S) minerals in anoxic sedimentary environments, where sulfate-reducing microorganisms (SRM) are ubiquitous. Biogenic Fe-S minerals formed in the presence of SRM have unique properties in comparison with minerals formed under abiotic conditions. The interface chemistry between organic and inorganic materials is studied using microscopy and spectroscopy to 1) understand the reactivity and transformation pathways of iron sulfide minerals in anoxic environments and at the oxic-anoxic boundary; and 2) evaluate if the composition, morphology and mineralogy of biominerals could be unique enough to serve as biosignatures for the search of life on other planets.
- Picard A., Gartman A., Clarke D.R., Girguis P.R. (2018) Sulfate-reducing bacteria influence the nucleation and growth of mackinawite and greigite. Geochimica Cosmochimica Acta, 220: 364-387.
- Picard A., Obst M., Schmid G., Zeitvogel F., Kappler A. (2016) Limited influence of Si on the preservation of Fe-mineral encrusted microbial cells during experimental diagenesis. Geobiology, 14: 276-292.
- Picard A., Kappler A., Schmid G., Quaroni L., Obst M. (2015) Experimental diagenesis of organo-mineral structures formed by microaerophilic Fe(II)-oxidizing bacteria. Nature Communications, 6: 6277.
- Picard A., Testemale D., Hazemann J.-L., Daniel I. (2012) The influence of high pressure on bacterial dissimilatory iron reduction. Geochimica et Cosmochimica Acta, 88: 120-129.
- Picard A. and Ferdelman T.G. (2011) Linking microbial heterotrophic activity and sediment lithology in oxic, oligotrophic sub-seafloor sediments of the North Atlantic Ocean. Frontiers in Extreme Microbiology, 2: 263.