Session : 1. Modalités et fréquence d’expulsion des fluides

Aurélien Gay (Université de Montpellier) : Dynamique d'expulsion des fluides dans les bassins sédimentaires

Session : 2. Nature et composition chimique des fluides expulsés et dévelopement des communautés bactériennes associées

Helge Niemann (NIOZ, Texel) : Microbes at cold seeps: how environmental determine their activity

Session : 3. Exemples de pockmarks et écosystèmes (communautés) benthiques associés dans les grands fonds marins

Giuliana Panieri (CAGE, Tromsø) : Pockmarks in the Arctic Ocean: Recent insights

Session : 4. Exemples de pockmarks et écosystèmes (communautés) benthiques associés dans la zone côtière

Jean-Claude Dauvin (Université de Caen) : Review of the genus Haploops Liljeborg, 1856 (Amphipoda, Ampeliscidae): from  taxonomy to dynamic of dense populations

The deadline for abstract submission is the 17th of december 2019.

These thematic days are organised to set up a state-of-the-art of knowledge and to improve exchanges and collaborations between geological and biological scientific communities.

Since 1990, numerous studies have focused on fluid circulations within the sedimentary column with a recent growing interest related to global warming. Fluids (gas e. g. methane, marine or fresh water, liquid hydrocarbons) migrate upwards with the possibility of i) creating depressions on the seafloor so-called « pockmarks » and ii) leading to fluid escapes in the water column.

In the deep sea (hundred to thousand meter water depths), the presence and development of benthic ecosystems remain closely limited by the small amount of organic matter that reaches the seafloor. Seeps and fluid expulsions are like life « oases » associated with chemio-synthetic organisms, thus demonstrating the link between pockmarks and ecosystems.

In contrast, in coastal areas (from shore to continental slope), multiplicity of nutrient sources makes the identification of benthic communities in association with fluid expulsions much more complex. Geologists, ecologists and micro-biologists, often still work separately, each having either identified the existence of pockmarks or specific microbial and benthic ecosystems. However, the exact relations between the two are still to be defined and explained. During these days, invited speaker conferences, oral communications on ongoing case studies and multidisciplinary round tables are going to take place enabling to compare different approaches on the way to solve the question: what roles do sedimentary fluids play in the development of present-day benthic ecosystems?