• Submarine canyons

    Submarine canyons

    Submarine canyons are recognized as ecological hotspots on continental margins, providing a number of services to ecosystems and humans. In the Mediterranean sea, canyons are particularly threaten by cumulated anthropogenic Read More
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Deep-sea hydrothermal vents

Chaire Capteurs Riftias

Hydrothermal vents on the ocean floor sustain a large diversity of ecosystems, in relation to different geological and oceanological contexts.
Microbial chemoautotrophy supporting carbon fixation from dissolved CO2 or methane is the basis of local organic matter production, feeding high-biomass hydrothermal communities.

 

These microbes gain energy from the chemically instable environments surrounding vents, where fluid reducing compounds (such as sulfide or hydrogen) coexist with seawater oxidizing compounds (such as oxygen or nitrate). Metals can play both roles depending on their redox state and also play a significant contribution to this energy budget. At hydrothermal vents, these 'geofuels' are abundant on the seafloor, driven geothermal heat transporting fluids within the seabed.

Our researches focus on integrated study sites that have benefited from a long-term multidisciplinary effort and are well caracterized in terms of community diversity and fluid geochemistry over space and time. The East Pacific Rise at lattitude 9°50'N and 13°N are associated with instable geosystems of this fast spreading ridge and provide model ecosystems to study the response and resilience of these ecosystems to volcanic eruption. On the Mid-Atlantic Ridge (MAR), the long-term stability of vent fields is conversely associated with large heterogeneity in fluid composition along the ridge, reflecting the different geological substrata, and offering contrasted environment to examine the capacity of diverse hydrothermal context to produce biomass on the seafloor.