microprony Project

We are studying the main microbial trophic groups that are directly linked to the geochemistry of these ecosystems associated with serpentinization (production of hydrogen and methane in particular), to better understand the mechanisms of adaptation in extreme conditions (alkaline pH) and their role in hydrothermal chimney growing. We try to reproduce in the laboratory the conditions favorable to the development of native microorganisms. The enrichment and isolation of microorganisms using hydrogen or methane in the absence of oxygen is a major challenge for our team, as they could be the first colonizers of the primitive Earth.

High amounts of hydrogen are emitted in the serpentinite-hosted hydrothermal field of the Prony Bay (PHF, New Caledonia), where alkaline, mesothermic and low-salinity fluids are discharged in both intertidal and shallow submarine environments.This original type of hydrothermalism had only been observed and considered in Lost City, discovered in 2000 at 800 meters below seawater near the Mid-Atlantic Ridge by American teams. At Prony, as at Lost City, the alkaline fluids are anoxic (poor in oxygen) and contain high quantities of hydrogen produced during the hydration of the rocks of the Earth’s mantle: an abiotic process called “serpentinization”. The hydrogen produced then reacts with surrounding carbon dioxide (carbon dioxide) to generate methane and other organic molecules such as alkanes, which can be used by microorganisms.