Submesoscale processes in the coastal margins of the Strait of Gibraltar. The Trafalgar – Alboran connection

•The processes behind the high productivity of Trafalgar area are clarified for the first time.•Relevance of transport processes along the Strait in the Alboran primary production.•Different submesoscale processes are responsible for this coastal transport. The present manuscript analyses the role of the submesoscale hydrodynamic patterns close to the coastal margin of the Strait of Gibraltar in the exchange of properties between the western side of the Strait and the western Alboran Sea. To achieve this goal a multi-approach analysis was performed using several datasets obtained during an oceanographic survey, drifters, satellite data and numerical simulation experiments. Three areas were identified: Trafalgar, Camarinal and the north-western corner of the Alboran Sea, in which the water exhibits a high residence time and relatively high phytoplankton concentrations. In addition, evidence of transport processes that take place along the coastal margin is shown between Trafalgar and the Alboran Sea. These transport processes seem to connect the phytoplankton that grows in the Gulf of Cadiz strip, in response to the nutrients supplied by the Guadalquivir River, to the phytoplankton populations in the western Alboran Sea. Furthermore, the transport of properties along this margin is clearly disrupted by strong and persistent easterly winds.