• 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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Lacaze-Duthiers canyon study site : a climate-sensitive deep-sea hotspot

The head of the Lacaze-Duthiers canyon in the southern end of the Gulf of Lion is located only 15 miles from the coast. This incision in the continental shelf ranges from 350m to 1000m depth. There, abundant colonies of cold water corals, Madrepora oculata and Lophelia Pertusa, unique in the western Mediterranean coast, associate with highly dynamic environmental conditions. Climate influences the key drivers of this dynamics: the circulation of water masses in the canyon and the transport of organic material from land, shelf and sea surface.  Disentangling the complex interactions between these processes and the living components of the ecosystem requires a long-term research effort which is crucial to assess its vulnerability in the context of global change.CarteLECOBSItes

 

Under the influence of strong and cold winds (Tramontane and Mistral), surface waters get denser than deeper water layers and suddently sink and trigger surface water flows toward the abyssal plain, through canyons. This phenomenon is named cascading. Dense water cascades typically last few weeks, and transport large amouts of solid and dissolved material from the shelf.
The climatic regime of this Mediterranean area is also known for strong storms and flash floods transporting large particulate and massive debris of terrestrial plans to the marine enviroment and, for extreme events, to the deep-sea environment of the canyon. There are thus strong links between the canyon hotspot ecosystem and climate, deserving specific attention.

In the last 5 years, a long-term study has been launched under the frame of the chair to investigate the dynamics and response of this ecosystem to climate-driven environmental instabilities. We seek to understand how the change in the intensity or frequency of cascading and strom events will impact ecosystem functions, including coral growth and the transformation of organic carbon sustained by canyon specific communities.