Fig. 6: Central and Intermediate water masses in the studied site GeoB9512-5 (15°20’13.20’N, 17°22’1.20”W, 793 m water depth).

a Temperature-Salinity diagram showing the water masses sources in the eastern North Atlantic, adapted from previous studies40,57, dashed lines represent the transition of North and South Atlantic Central Waters (NACW and SACW, respectively) in the eastern North Atlantic85. b Salinity showing the eastern North Atlantic central water masses distribution in the studied area40. c Dissolved oxygen concentration (umol/kg)43 and modern extension at depth of the East North Atlantic Oxygen Minimum Zone (ETNA). Oceanographic sections (a and b) were plotted with Ocean Data View99 using the GLODAP v2.2022 oxygen data base43, interpolated by DIVA.