N₂O dynamics in the western Arctic Ocean during the summer of 2017

The western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N₂O) cycles from greenhouse gases. We investigated WAO N₂O dynamics through an intensive and precise N₂O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0-50 m) and deep layers (200-2200 m) of the northern Chukchi Sea with an under-saturation of N₂O. By contrast, both the surface layer (0-50 m) of the southern Chukchi Sea and the intermediate (50-200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N₂O production (i.e., through nitrification), with N₂O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N₂O (mean: + 2.3 ± 2.7 μmol N₂O m^-2 day^-1), whereas the northern region acted as a sink (mean - 1.3 ± 1.5 μmol N₂O m^-2 day^-1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N₂O "hot spot", and therefore, a key region requiring continued observations to both understand N₂O dynamics and possibly predict their future changes.