| Summary: | The National Natural Science Foundation of China (NSFC) [40906102, 41230529]; CHINARE [-01-04-02, 01-02-01, 03-04-02]; CAA International Cooperation Projects [IC201201, IC201308] Nitrous oxide (N2O) distribution patterns in the Bering Sea basin (BSB) and Indian Sector of the Southern Ocean (ISSO) were described and compared. In both sites, the waters were divided into four layers: surface layer, subsurface layer, N2O maximum layer, and deep water. Simulations were made to find out the most important factors that regulate the N2O distribution patterns in different layers of both sites. The results showed that in the surface water, N2O was more understaturated in the ISSO than the BSB. This phenomenon in the surface water of ISSO may result from ice melt water intrusion and northeastward transport of the Antarctic surface water. Results of the rough estimation of air-sea fluxes during the expedition were (-0.34 +/- 0.07)-(-0.64 +/- 0.13) mu mol/(m(2)center dot d) and (-1.47 +/- 0.42)-(-1.77 +/- 0.51) mu mol/(m(2)center dot d) for the BSB and the ISSO, respectively. Strongly stratified surface layer and temperature minimum layer restricted exchange across the thermocline. The N2O maximum existed in higher concentration and deeper in the BSB than the ISSO, but their contribution to the upper layer by eddy diffusions was negligible. In deep waters, a concentration difference of 5 nmol/L N2O between these two sites was found, which suggested that N2O production occurred during thermohaline circulation. N2O may be a useful tracer to study important large-scale hydrographic processes.
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