Abstract
The western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N(2)O) cycles from greenhouse gases. We investigated WAO N(2)O dynamics through an intensive and precise N(2)O 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 N(2)O. 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 N(2)O production (i.e., through nitrification), with N(2)O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N(2)O (mean: + 2.3 ± 2.7 μmol N(2)O m(-2) day(-1)), whereas the northern region acted as a sink (mean - 1.3 ± 1.5 μmol N(2)O 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 N(2)O "hot spot", and therefore, a key region requiring continued observations to both understand N(2)O dynamics and possibly predict their future changes.