Abstract


THE C3 GROUP : A RARE BUT ACTIVE THAUMARCHAEAL GROUP IN INTERTIDAL MUDDY SEDIMENT

In intertidal benthic ecosystems, environmental conditions shaped the inhabiting prokaryotic communities during emersion period. Aiming at simplifying the complexity of intertidal mudflats, we developed a tidal mesocosm approach allowing sampling the top 10 cm of sediment. In this study, we removed macrofauna that can be the major prokaryotic grazers and can strongly impact sediment vertical structuration. Moreover, we suppressed hydrodynamic pressure and thus decreased resuspension phenomenon suspected to modify prokaryotic communities on the field. The active diversity of archaeal community evaluated through 16S rRNA transcripts 454 pyrosequencing, revealed that the majority of metabolically active Archaea (more than 60%) fell into Thaumarchaeota lineage known to be largely involved in ammonia oxidation. Between the surface and 5 cm depth, the MGI dominated the active community. Deeper, between 5 and 10 cm depth, the C3 group was highly active. This sharp shift suggested drastic modifications in sedimentary properties, as C3 group are supposed to be specific to anoxic sediments. While, it is unlikely that these organisms could be ammonia oxidizers, it raises compelling hypothesis on their putative functional role. Our work highlighted the importance of focusing further studies on rare prokaryotic groups that might be involved in ecosystem functioning.

Authors

AGOGUE, H., CNRS, France, helene.agogue@univ-lr.fr

HUGONI, M., Clermont University, France, mhugoni@hotmail.fr

DUPUY, C., La Rochelle University, France, c.dupuy@univ-lr.fr

LAVERGNE, C., La Rochelle University, France, celine.lavergne@univ-lr.fr

Details

Poster presentation

Session #:075
Date: 2/26/2015
Time: 18:30 - 20:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 323