Guillaume Tahon

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The role of photoheterotrophic and chemoautotropic prokaryotes in the microbial food web in terrestrial Antarctica: a cultivation approach combined with functional analysis


In continental Antarctica with its extremely harsh environmental conditions, where ecosystems are dominated by microorganisms and the food webs are relatively simple, the main primary source of organic carbon (and energy) and fixed nitrogen for microbial communities is generally thought to be photosynthesis by cyanobacteria. However, there are sites where this group is less abundant in the microbial communities present. This thesis topic fits in the framework of a project were we investigate the hypothesis that in such situations, alternative mechanisms for CO2 fixation and mechanisms for exploiting solar energy may exist and these will provide the energy required for nitrogen fixation.

This research focuses on terrestrial samples gathered in the proximity of the Princess Elisabeth Station. We will explore the diversity of several alternative mechanisms by studying the presence and diversity of key genes for these processes, using PCR clone libraries. We will also perform a large-scale isolation campaign from selected terrestrial Antarctic samples to obtain bacterial cultures that harbor these alternative mechanisms, combined with a reverse metagenomics approach, to quickly obtain our bacteria of interest.