Microbialites are organosedimentary structures formed under the influence of phylogenetically and functionally diverse microbial communities in interaction with abiotic factors. Fossil stromatolites represent the oldest undisputed evidence of life on Earth (~3.7 Ga). Yet, the specific identity and functions of associated microorganisms and the local environmental conditions resulting in their formation and long-term preservation are poorly understood. Over the past years, we have studied both ancient microbialites, looking for potential traces of life as well as modern microbialites to decipher microbialite formation processes from the nanoscale to the macroscale.
We currently run an ANR project named Microbialites. See here for some details.

Characterization of ancient microbialites at the nanoscale

Combination of Raman, FIB, TEM and STXM analyses on Tumbiana microbialites

                Lepot et al (2008) Nature Geoscience

                Lepot et al (2009) Geochim. Cosmochim. Acta

Processes of biomineralization of carbonates and authigenic silicates in modern microbialites

Oriented precipitation of aragonite precipitation by Pleurocapsales

                    Couradeau et al (2013) Biogeoscience
                    Gerard et al (2013) ISME J

Authigenic formation of hydrated Mg-silicates in microbiailtes

                    Zeyen et al (2015) Frontiers in Earth Science

Taxonomic and functional diversity of microorganisms populating microbialites

Taxonomic diversity of microorganisms in microbialites

Lopez-Garcia et al (2005) Extremophiles; Couradeau et al (2011) PlosOne; Saghaï et al (2015) Frontiers in Microbiology

Functional diversity of microorganisms in freshwater microbialites

                    Saghaï et al (2016) Env. Microbiol


Karim BENZERARA     Modifié le 09 Mai 2019