High frequency of sediment gravity flow events in the Var submarine canyon (Mediterranean Sea)

This study aimed to analyze the role river floods play in triggering gravity flows and to investigate the role of submarine canyon systems as a conduit for terrigenous material to the deep sea. Two years of measurements in the Var canyon at depths ranging from 1200 m to 2350 m indicate that six floods of the Var River triggered hyperpycnal flows, an important mechanism for transporting particulate matter to the deep-sea floor. These sediment gravity flows were characterized by a sudden increase of current velocity that lasted 8 to 22 h and by downward particle fluxes that reached up to 600 g m− 2 d− 1 of particles and 3.1 g m− 2 d− 1 in terms of organic carbon. These large inputs of sediment and organic carbon may have a significant impact on deep-sea ecosystems and carbon storage in the Mediterranean Sea.