Preservation of ancestral Cretaceous microflora recovered from a hypersaline oil reservoir

Gregoire Gales (1) , Nicolas Tsesmetzis , Isabel Neria , Didier Alazard (1) , Stéphanie Coulon (2) , Bart P. Lomans , Dominique Morin (2) , Bernard Ollivier (1) , Jean Borgomano , Catherine Joulian (2)

1 MIO - Institut méditerranéen d'océanologie
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

Microbiology of a hypersaline oil reservoir located in Central Africa was investigated with molecular and culture methods applied to preserved core samples. Here we show that the community structure was partially acquired during sedimentation, as many prokaryotic 16S rRNA gene sequences retrieved from the extracted DNA are phylogenetically related to actual Archaea inhabiting surface evaporitic environments, similar to the Cretaceous sediment paleoenvironment. Results are discussed in term of microorganisms and/or DNA preservation in such hypersaline and Mg-rich solutions. High salt concentrations together with anaerobic conditions could have preserved microbial/molecular diversity originating from the ancient sediment basin wherein organic matter was deposited.

Domaines: Biodiversité et Ecologie; Environnement et Société; Milieux et Changements globaux; Ingénierie de l'environnement

Gregoire Gales, Nicolas Tsesmetzis, Isabel Neria, Didier Alazard, Stéphanie Coulon, et al.. Preservation of ancestral Cretaceous microflora recovered from a hypersaline oil reservoir. Scientific Reports, 2016, 6, ⟨10.1038/srep22960⟩. ⟨hal-01443597⟩