[Nitrous oxide flux at the water-air interface of the rivers in Nanjing during summer].

Employing floating static chamber-chromatography method,the N 2 O diurnal fluxes at the water-air interface of four rivers( Tuanjie River,Jinchuan River,Inner and Outer Qinhuai River) and Jinniu Lake were monitored in Nanjing during summer. The results show that four rivers act as the sources of N 2 O emission,but Jinniu Lake is characterized by the absorption of N 2 O. The highest N 2 O flux from Inner Qinhuai presented at 20: 00 because of the changing of hydrodynamic conditions. Both Jinchuan and Tuanjie rivers' minimum N 2 O fluxes were detected when the content of dissolved oxygen was extremely low. The tendency of N 2 O from Outer Qinhuai showed a double-peak because of its daytime nitrification and nocturnal denitrification. The flux of N 2 O from Jinniu Lake had been noted as being generally higher at night than that during light hours due to the effect of wind. For natural rivers,the proper sampling period is from 08: 00 to 12: 00,but for the river subjected to interference,the sampling period is different.