The air–sea exchange and oceanic cycling of nitrous oxide (N₂O) are fundamental in controlling the evolution of the Earth’s atmospheric chemistry and climate. Significant advances have been made over the last years in understanding, instrumentation and methods, as well as deciphering the production and consumption pathways of N₂O in the upper ocean (including the surface and subsurface ocean down to approximately 1000 m). The global ocean under current conditions is now well established as a major source for N₂O. however, there are still considerable uncertainties about the processes and their major drivers controlling the distributions of N₂O in the upper ocean. Without having a fundamental understanding of oceanic N₂O production and consumption pathways, our knowledge about the effects of ongoing major oceanic changes such as warming, deoxygenation, and eutrophication on the oceanic cycling and air–sea exchange of N₂O remains rudimentary at best. I suggest that only through a comprehensive, coordinated, and interdisciplinary approach that includes data collection by global observation networks as well as joint process studies can the necessary data be generated to (1) identify the relevant microbial and phytoplankton communities, (2) quantify the rates of oceanic N2O production and consumption pathways, and (3) comprehend their major drivers.

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