Stratification of Archaea in the Deep Sediments of a Freshwater Meromictic Lake: Vertical Shift from Methanogenic to Uncultured Archaeal Lineages

Guillaume Borrel (1) , Anne-Catherine Lehours (1) , Olivier Crouzet (1) , Didier. Jézéquel (2) , Karl Rockne (3) , Amelie Kulczak (1) , Emilie Duffaud (4) , Keith Joblin (1) , Gérard Fonty (4)

1 LMGE - Laboratoire Microorganismes : Génome et Environnement
2 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
3 UIC - University of Illinois [Chicago]
4 LMGE - Laboratoire Microorganismes : Génome et Environnement

As for lineages of known methanogens, several lineages of uncultured archaea were recurrently retrieved in freshwater sediments. However, knowledge is missing about how these lineages might be affected and structured according to depth. In the present study, the vertical changes of archaeal communities were characterized in the deep sediment of the freshwater meromictic Lake Pavin. For that purpose, an integrated molecular approach was performed to gain information on the structure, composition, abundance and vertical stratification of archaeal communities thriving in anoxic freshwater sediments along a gradient of sediments encompassing 130 years of sedimentation. Huge changes occurred in the structure and composition of archaeal assemblages along the sediment core. Methanogenic taxa (i.e. Methanosaeta and Methanomicrobiales) were progressively replaced by uncultured archaeal lineages (i.e. Marine Benthic Group-D (MBG-D) and Miscellaneous Crenarchaeal Group (MCG)) which are suspected to be involved in the methane cycle.

Domains: Sciences of the Universe [physics]; Earth Sciences

Guillaume Borrel, Anne-Catherine Lehours, Olivier Crouzet, Didier. Jézéquel, Karl Rockne, et al.. Stratification of Archaea in the Deep Sediments of a Freshwater Meromictic Lake: Vertical Shift from Methanogenic to Uncultured Archaeal Lineages. PLoS ONE, 2012, 7 (8), pp.e43346. ⟨10.1371/journal.pone.0043346⟩. ⟨insu-02542699⟩