Research progress in nitrogen and oxygen isotopic composition of marine nitrous oxide

Nitrous oxide (N₂O) is an important greenhouse gas, and plays a significant role in the stratospheric ozone depletion. Atmospheric N₂O concentration has been increasing at an annual rate of 0.25%, primarily due to human activities. Marine waters are the major hotspot of N₂O production. The nitrogen and oxygen isotope of N₂O are tracers for the production and consumption of N₂O in the ocean, which is a useful tool for marine N₂O cycle study. Herein, we present a brief review of marine N₂O production and consumption in the context of the nitrogen cycle. Then nitrogen and oxygen isotopic composition of N₂O in different environment and the isotopic fractionation effect on N₂O cycle were summarized. Current applications of nitrogen and oxygen isotope in the associated processes of N₂O in the marine systems were reviewed. Finally, we commented the current status and perspective of applying nitrogen and oxygen isotope in the N₂O cycle in the coastal China Sea.