This dataset includes calculated data over the epi-mesopelagic layer (0-800 m depth) of 26 stations with 14 of them inside or in the vicinity of a cyclonic eddy that formed off Mauritania along the ∼ 900 km zonal corridor between Mauritania and the Cabo Verde islands in the eastern Tropical North Atlantic during the M156 cruise on the RV Meteor from July 3rd to August 1st 2019. The apparent oxygen utilization was calculated as the difference between saturation concentrations of O2 and measured O2 concentrations: AOU= [O2sat ({}{}θ{}{}, S)] − [O2], with S = salinity and θ = potential temperature (Redfield, 1942; Redfield et al., 1963; Pytkowicz, 1971). The saturated oxygen (O2sat) was computed using measured temperature and salinity following 212 Garcia and Gordon (1992). Relative percentage of South Atlantic Central Water was determined as in Klenz et al., (2018).