Enrichment of nitrous oxide in the water columns in the area of the Bering and Chukchi Seas

We found N2O enrichment of up to 157% saturation in continental shelf water columns in the Bering and Chukchi Seas at water depths less than 66 m. The N2O enrichment exhibited a linear relationship with N* depletion. We also observed that the stable isotopic characteristics of N2O are an enrichment of 18O and a depletion of 15N relative to atmospheric N2O. We conclude that N2O in the area is primarily produced through denitrification in sediments. By using the observed instantaneous N2O emission rate, we estimated the annual emission rate from the surface to the atmosphere in the area to be 0.097 ± 0.065 Tg N year− 1, which corresponds to 0.6% to 10% of the total oceanic emission. The area of the Bering and Chukchi Seas could be very important in understanding global oceanic N2O emission.