Contribution of N2O by the Arctic Ocean to global N2O budget was once neglected since it was covered by sea ice, which acts as a barrier to inhibit the exchange of N₂O between the ocean and the atmosphere. With progressing of global warming, fast retreat of sea ice expose more surface water area of the Arctic Ocean to atmosphere, probably enhance the air sea exchange of N₂O. Taking advantage of the Chinese National Arctic Research Expeditions and MOSAiC expeditions, together with data from other studies, the distribution pattern of N₂O in the Arctic Ocean were studied, the result shows that: the continental shelves of the Chukchi Sea, Siberian Sea and Arctic Northwest Passage are generally act as source of N₂O; whereas in the open ocean, the West Arctic Ocean is influenced by the Pacific water inflow from the Bering Strait, carrying the relative old and N₂O enrich water, into the Arctic Ocean. However, being suppressed by stratification, this region does not show obvious source or sink characteristics; whereas in the Eastern Arctic Ocean, the Northward intruding water mass shows characteristics of N₂O undersaturation since decreasing of water temperature increase its N₂O solubility. However, there are also study suggested that oxygenated denitrification may be a possible mechanism to lead to this N₂O undersaturation. In a word, the Arctic open water may act as a weak sink as whole for N₂O, whereas the continental shelves may act as a source. Further studies are needed to address their mechanism and to predict the future tend of this N₂O source and sink characteristics.

 

nitrous oxide, Arctic Ocean