Old City hydrothermal field Targeted loci environmental

The discovery in 2000 of active microbiomes associated with the alkaline hydrothermal field of Lost City near the Mid Atlantic Ridge went far in changing our vision of how life has emerged on Earth and of the conditions under which life can thrive on our planet and perhaps on others as well. No other similar hydrothermal field was reported up to now alongthe ridge system, making Lost City unique. We propose to investigate the microbial diversity of the new Lost City like hydrothermal field of Old City discovered along the South West Indian Ridge during the recent ROV-SMOOTH cruise in 2016. During this cruise, carbonated chimneys, serpentinized peridotites and hydrothermal fluids were sampled. With the sequencing of the DNA extracted from these samples, we expect to highlight the structure and ecological functions of the microbial community hosted in the carbonated chimneys and underlying basement. Jointly with geochemical and mineralogical characterization 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, [e-mail]