DNA has been extracted from several carbonated chimneys associated with the alkaline hydrothermal field of Lost City near the Mid Atlantic Ridge, revealing a dense microbial community likely dominated by Bacteria. Metagenomic sequencing of the DNA extracted from these samples may provide evidences on the sources of carbon and energy fueling serpentinization associated subseafloor microorganisms and how they evolve in carbonated chimneys. Jointly with the results on microbial diversity, geochemistry and mineralogy at the microscale, this study will improve our knowledge on the functioning of serpentinization-based microbial ecosystems, their habitats and their implications for the early evolution of life. PI: Aurelien Lecoeuvre, lecoeuvre@ipgp.fr