Oxygen and nutrient trapping in the southern Benguela Upwelling System

Here, we compiled data obtained from a research cruise with the German RV Meteor (M153) and an oceanographic mooring to demonstrate that a nutrient trapping zone develops in a narrow belt along the coast during the main upwelling season in the southern Benguela Upwelling System (SBUS). It modifies links between the strength of upwelling, productivity and the intensity of the oxygen minim zone (OMZ) in the SBUS. During the cruise M153 shipboard measurements were conducted along a station grid in the SBUS between February 16th and 28th, 2019. This included CTD casts, one TRIAXUS transect and the deployment of one mooring equipped with a Mini Dot Oxygen Sensor (MDO) and Hydrobios MST-12 sediment trap at water-depth of approximately 95.5 m. In order to study the diurnal cycle, four CTD casts were conducted between February 18th and 19th at station 7 close to the mooring location while mooring data and publically available satellite data on sea surface temperature and primary production were used to study the seasonal cycles of the nutrient trapping zone.