Expertise

Geomicrobiology, Biogeochemistry, Microscopy, Spectroscopy

Research

Picard's research investigates microbe-mineral interactions in the context of microbial physiology, biogeochemistry and astrobiology. The focus is on interactions between sulfate-reducing microorganisms (SRM), which are ubiquitous in anoxic sedimentary environments, and iron sulfide minerals. She uses microscopy and spectroscopy to 1) understand the properties and transformation pathways of iron sulfide minerals in anoxic environments and at the oxic-anoxic interface; 2) evaluate if the composition, morphology and mineralogy of biominerals is unique enough to serve as biosignatures for the search of life on other planets; and 3) assess the role of minerals on microbial activity and survival.

Selected Publications

• Nabeh, N., Brokaw, C., & Picard, A. (2022). Quantification of organic carbon sequestered by biogenic iron sulfide minerals in long-term anoxic laboratory incubations. Frontiers in Microbiology, 1360.
• Picard, A., Gartman, A., & Girguis, P. R. (2021). Interactions between iron sulfide minerals and organic carbon: implications for biosignature preservation and detection. Astrobiology, 21: 587-604.
• Picard, A., Gartman, A., Cosmidis, J., Obst, M., Vidoudez, C., Clarke, D. R., & Girguis, P. R. (2019). Authigenic metastable iron sulfide minerals preserve microbial organic carbon in anoxic environments. Chemical Geology, 530: 119343.
• 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., 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.