Gulf of Lions - Environment

The Gulf of Lions is a continental margin in the north-west Mediterranean Sea, with a large crescent-shaped continental shelf. Along the continental slope, the main mesoscale circulation feature is the Northern Current, a strong geostrophic current, which generally flows along the continental slope. More than ten rivers with a total watershed area of about 125,000 km2 discharge significant volumes of water into the gulf.  The Rhône River on the north-eastern part of the Gulf discharges about 80% of the total riverine water inputs. The dominant drivers in the area are the strong north-western (tramontane) and northern (mistral) winds which induce strong coastal upwelling activity, the western Mediterranean mesoscale circulation, and the fresh water input from the Rhone River. These drivers generate important primary and secondary production in the Gulf. The Gulf of Lions has a decreasing trend in nutrient concentration and production from east to west and from the continental shelf to deeper waters. The substrate is characterised by muddy and sandy bottoms. The shoreline is largely urbanized (ca. 1.5 million inhabitants).