Diatom communities from biofilms through time and regarding four differents locations : Toulon Bay, Banyuls-sur-Mer, Reunion Island and Lorient

This study aimed at the description of marine diatoms communities from biofilms from PVC (Polyvinyl chloride) panels immersed (i) during one year in two Mediterranean sites (Toulon bay in the NW Mediterranean Sea and Banyuls bay in the NW Mediterranean Sea) and (ii) during one month in Toulon bay, in Lorient (in the Southern Coast of Brittany in the Atlantic Ocean), and in the Reunion Island (in the Indian Ocean). Attention was given to the relation between diatoms and others microorganisms of biofilms (prokaryotes and fungi).We observed that diatom richness was maximal from the early stages of biofilm formation and showed a clear temporal evolution of Beta-diversity in Mediterranea. We were able to elucidate how microorganisms interact within biofilms throughout the colonization process of the Plastisphere. Comparing Toulon, Reunion and Lorient, we observed that environmental parameters remained the stronger drivers structuring diatoms communities.The specificity of diatoms among other microorganisms of biofilms was characterized by tychoplanktonic taxa. A complete absence of common genetic variants between Lorient, Reunion Island and Toulon suggested adaptation processes.