A study on the role of sea ice in the nitrous oxide cycle in the Prydz Bay, Antarctica

N 2 O is one of the most important greenhouse gases and ozone depletor, which was a matter of more and more concerned. The Southern Ocean was considered as one of the most important N 2 O source and was believed to account for ~1/4 of oceanic budget. However, there is uncertainty about this budget due to limited data availability. In this study, field and lab works were conducted for better understanding of N 2 O dynamics during sea ice melting and sea ice formation. In the field study, taking advantage of the Chinese Antarctic cruise, a 10 days’ time series study was carried out at a station in the Prydz Bay, Antarctica, where, surface water N 2 O was observed continuously, and the adjacent ice cores were taken for N 2 O analysis. In the lab, an ice growing simulation system was constructed to study the N 2 O dynamics during the sea ice formation. The result of endmember mixing models and calculation of N 2 O partition in three phases during sea ice formation provide important information about the dynamics of N 2 O during ice melting and sea ice formation processes, that is, the sea ice melting regulated N 2 O concentration and saturation status, which can be an explanation for reported N 2 O undersaturation observed in polar oceans, whereas during the sea ice formation, most of the N 2 O will be expelled to the deeper water while a small amount of retain the sea ice and less amount of N 2 O release to the atmosphere.