Nitrous oxide dynamics in the Arctic Siberian shelves of the North Kara Sea during summer 2021

Nitrous oxide (N2O) distribution in the North Kara Sea during summer 2021 shows elevated N2O concentrations in shelf water masses, highlighting the significance of coupled benthic-pelagic and nitrification-denitrification processes. In surface waters, temperature emerges as the primary driver of N2O concentrations, with a clear negative correlation between both parameters. Most surface waters are near saturation for N2O, and the saturation deficit exhibits an inverse relationship with temperature. Under-ice water influx originating from the open ocean exhibits strong under-saturation (80%), attributed to the limited air-sea exchange in sea ice covered waters. Contrary to expectations, river supply does not exert a discernable influence on N2O concentrations in the studied area. This study reveals the potential of the Arctic Siberian shelves for the uptake of atmospheric N2O during summer.