Vertical profiles of dissolved oxygen (O2) concentrations in the surface sediment of the North Atlantic Basin were acquired during MSM96 through ex-situ voltametric measurements during this research cruise. For every multicorer station, one liner was selected and transported to the on-board cool room immediately for analysis at 5°C. At some stations, a second core was analyzed for validation and to achieve better measurement resolution. Measurements were carried out through cyclic voltammetry (start: -100 mV, vertex: -1900 mV, start: -100 mV, scan rate: 500 mv/s) with Hg/Au microelectrodes (100 µm diameter) in a 3-electrode configuration with an Ag/AgCl pseudoreference electrode and a Pt counter electrode using a modified custom version of the DStat open source potentiostat (Dryden & Wheeler, 2015; doi:10.1371/journal.pone.0140349). Working electrodes were polished and Hg-plated prior to the research cruise according to the method by Brendel & Luther III (1995; doi:10.1021/es00003a024) and repolished (using diamond polishing plates of 5, 1 and 0.25 µm grit) and plated (180s at -100mV in 0.1M Hg(NO3)2 solution) on board when degradation of the signal was detected (twice over the duration of the cruise). Measurements were calibrated to 100% O2 saturation in bottom water at equilibrium with the atmosphere after recording air pressure and temperature to calculate dissolved O2 concentration as well as 0% O2 saturation in bottom water that was purged of oxygen by bubbling with nitrogen (N2) gas. The sensor was moved vertically on a linear axis with a stepper motor through an automated control system hosted on a Raspberry Pi control unit.