Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Marine Pollution Bulletin 115-125 Biogeochemical functioning Diversity Hydrocarbonoclastic bacteria Microbial mats FRANCE MEDITERRANNEE BERRE ETANG 2016 fdi:010068229 ENG Marine Pollution Bulletin 0025-326X ISI:000384854100023 1-2 10.1016/j.marpolbul.2016.07.023 https://www.documentation.ird.fr/hor/fdi:010068229 https://www.documentation.ird.fr/intranet/publi/2016/11/010068229.pdf 111 Horizon (IRD) Photosynthetic microbial mats are metabolically structured systems driven by solar light. They are ubiquitous and can grow in hydrocarbon-polluted sites, Our aim is to determine the impact of chronic hydrocarbon contamination on the structure, activity, and functioning of a microbial mat. We compared it to an uncontaminated mat harboring similar geochemical characteristics. The mats were sampled in spring and fall for 2 years. Seasonal variations were observed for the reference mat: sulfur cycle-related bacteria dominated spring samples, while Cyanobacteria dominated in autumn. The contaminated mat showed minor seasonal variation; a progressive increase of Cyanobacteria was noticed, indicating a perturbation of the classical seasonal behavior. Hydrocarbon content was the main factor explaining the differences in the microbial community structure; however, hydrocarbonoclastic bacteria were among rare or transient Operational Taxonomic Units (OTUs) in the contaminated mat We suggest that in long-term contaminated systems, hydrocarbonoclastic bacteria cannot be considered a sentinel of contamination. 036 ; 084 ; 038 UR248 / UR235 / UR234