The aim of the MICROMET project was to study the interactions between metallic contaminants and microbial communities (Archae, Bacteria, and micro-Eukarya) living in marine sediments of the BCP. The research was composed of three main parts in which microbiological and geochemical approaches were closely integrated. The first part (Work Package 1 - WP 1) was devoted to an in depth analysis of the impact of metallic contaminants on the microbial diversity of sediments using a combination of state-of-the-art molecular and geochemical tools. For that, 9 stations were selected on the BCP. The aim of the second part (WP 2) was to assess the importance of microorganisms in the leaching of metallic contaminants from the sediments into the water column. In the third part (WP 3) geochemical modelisation was performed with the results obtained previously in order to better characterize metal fluxes in the sediments. During the whole MICROMET project, special attention was paid to the influence of organic matter, particularly phytodetritus, on the relationship between benthic microbes and metals. Organic matter has been identified in previous researches as one of the main force affecting the diversity and activity of microbial communities.