Assessment of the global budget of nitrous oxide (N2O) is limited by poor knowledge of the oceanic N2O flux to the atmosphere, whose magnitude, variability, and drivers are still uncertain. In the first part of the talk, I discuss a new, data-based reconstruction of oceanic N2O emissions that captures coastal hotspots and reveals a vigorous, globally synchronous seasonal cycle. In the second part of the talk, I discuss results from a high-resolution model of the Eastern Tropical South Pacific that resolves N2O cycling in oxygen-deficient waters. I show that denitrification is a dominant source of N2O, and that “eddy reaction” terms at the boundary of oxygen minimum zones enhance the rate of N2O production and reshape the anaerobic nitrogen cycle.