Abstract: Water samples collected from Prydz Bay and the adjacent Southern Ocean during the 25th and 26th Chinese Antarctic Research Expeditions were analyzed for N₂O concentration using the static headspace gas chromatography method. The concentration of N₂O over the Prydz Bay continental shelf was found to be relatively low, with a range of 13.2—17.4 nmol·L⁻¹, and it was undersaturated compared with the current atmospheric mixing ratio, with saturation anomaly centers at −7%. However, higher concentrations of N₂O, with a range of 15.5—23.3 nmol·L⁻¹, were found in the Southern Ocean. The subsurface to bottom waters all showed oversaturation against the atmospheric mixing ratio prior to the industrial revolution. It was established that the distribution pattern of N₂O within the study area was related to the complex hydrographic characteristics of the region. Prydz Bay shelf water with undersaturated N₂O might mix with Circumpolar Deep Water and sink to the bottom of the Southern Ocean, forming Antarctic Bottom Water. This could act as a pathway for N₂O transportation into deep water, providing a sink for atmospheric N₂O.

Key words: N₂O, Antarctic, Prydz Bay, Southern Ocean, greenhouse gas