Oceanic processes in the Gulf of Lion Our knowledge of oceanic processes along our coastlines is incomplete – despite their proximity to us. EU scientists studied the dominant current shaping biological and physical processes in the Gulf of Lion, off the French Mediterranean coast. Food and Natural Resources © Bardocz Peter, Shutterstock Shelf and coastal regions are areas of high biological productivity and biogeochemical cycling. However, the proximity of these areas to human settlements means they are also heavily affected by human activities. Despite being located close to us, shelf and coastal regions – particularly their functioning and processes – remain poorly understood. This is because models of general ocean circulation fail to represent natural processes at the scale of coastal seas. To further complicate things, satellite estimates of primary production can be unreliable. The EU-funded SEAQUEST (Meso and sub-mesoscale physico-biogeochemical dynamics in a coastal NW Mediterranean Sea: Quantifying and understanding ecosystem structure and transport) initiative used an interdisciplinary approach to study oceanic processes in the Gulf of Lion. This region is highly productive and an important feeding ground for fish, birds and mammals – both resident and migratory. The particular focus of SEAQUEST was the Northern Current. This current passes along the continental slope off the Gulf of Lion, where it is the dominant circulation feature. For this study, scientists employed two approaches. They used high-resolution, coupled 3D modelling, and observational data from cruises, satellites, and radar. Project researchers gathered in situ data during one particular cruise (cruise report) which coincided with a mistral event. The mistral is a strong, cold, northerly wind that blows into the Gulf of Lion. The Mistral led to a temporary weakening and near shutdown of the Northern Current blurring the borders between the typically very distinct biogeochemical provinces created by this current; once the Mistral event had subsided, the current re-established itself. Further analysis and modelling will help to explain the impact this had on cross-shore transport and the ecosystem as a whole. SEAQUEST is providing insights into the ecosystem function and biogeochemical-physical processes in the Gulf of Lion – an important and productive coastal area in Europe. The results will be relevant to various stakeholders in this area, including local managers and decision-makers. Keywords Oceanic processes, Gulf of Lion, biogeochemical, SEAQUEST, Northern Current
