Complex microbial communities and the challenge of environmental adaptation : strength in numbers

Whatever the ecological niche, the extreme diversity of the microbial world has created the conditions for community life. This has been structured around a number of symbioses, the integration of which not only dictates the ecological rules governing these communities, but also imposes selective pressure on the participating micro-organisms and thus on their evolution. Three aspects were extensively developed during this seminar: microbial symbioses sensu stricto (phototrophic, heterotrophic and chemotrophic), symbioses between micro- and macro-organisms (syntrophies such as nitrogen transfer and endosymbioses) and the role of symbioses in the origin of eukaryotic cellular organelles such as the chloroplast and mitochondria.