Enhanced ventilation of Eastern North Atlantic Oxygen Minimum Zone with deglacial slowdown of Meridional Overturning

Abstract The eastern Tropical North Atlantic Oxygen Minimum Zone (ETNA OMZ) sustains unique marine ecosystems off northwestern Africa. One of the key controls of the ETNA OMZ is ventilation driven by the subsurface ocean circulation of the Atlantic subtropical gyres. However, how this shallow circulation interacts with changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) remains unclear. Here, we present a new deglacial and high-resolution paleo-oxygenation record (GeoB9512-5, 793 m water depth) from the low oxic waters of the margin of ETNA OMZ, that registers more strongly oxygenated periods during the Last Glacial Maximum (LGM), two parts of the Heinrich Stadial 1 (HS1), and the latter part of the Younger Dryas (YD). We show that steeper meridional temperature gradients during HS1 and YD with AMOC slowdown intensified the subsurface subtropical gyre circulation and the oxygen supply to the ETNA.