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Abstract Nitrous oxide (N 2 O) is important to the global radiative budget of the atmosphere and contributes to the depletion of stratospheric ozone. Globally the ocean represents a large net flux of N 2 O to the atmosphere but the direction of this flux varies regionally. Our understanding of N 2 O production and consumption processes in the ocean remains incomplete. Traditional understanding tells us that anaerobic denitrification, the reduction of NO 3 − to N 2 with N 2 O as an intermediate step, is the sole biological means of reducing N 2 O, a process known to occur in anoxic environments only. Here we present experimental evidence of N 2 O removal under fully oxygenated conditions, coupled with observations of bacterial communities with novel, atypical gene sequences for N 2 O reduction. The focus of this work was on the high latitude Atlantic Ocean where we show bacterial consumption sufficient to account for oceanic N 2 O depletion and the occurrence of regional sinks for atmospheric N 2 O.