Abstract: | To investigate the water-air diffusive greenhouse gases (GHGs) fluxes from the Three Gorges Reservoir (TGR), a field experiment on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes from water surface was carried out from March 2011 to August 2012 by floating static chamber method. The results showed that CO2 was released to the atmosphere all the time and was less in autumn than in other seasons (P < 0.05). CH4 was also released to the atmosphere throughout the year but more in summer than other three seasons (P < 0.05). N2O flux was higher in autumn than other seasons (P < 0.05), and N2O was absorbed from the atmosphere mainly in summer. Moreover, correlation analysis illustrated that CO2 flux had significantly negative correlation with wind velocity (P < 0.05), whereas positive correlation with pH (P < 0.01) had been found. There was no significant correlation between CH4 (or N2O) flux and the measured environmental variables respectively (P > 0.05). Additionally, the annual fluxes of CO2, CH4 and N2O were 140.45 ± 12.57 mg CO2·m?2 h?1, 1.35 ± 0.14 mg CH4·m?2 h?1 and 34.34 ± 11.64 μg N2O·m?2 h?1, respectively. When compared to other reservoirs worldwide, the CO2 and N2O fluxes from TGR were higher than those from boreal and temperate reservoirs, but much lower than those from tropical reservoirs. CH4 flux was lower than those from boreal, temperate and most tropical reservoirs. In our study, the surface area of the TGR emitted 1.42 × 106 t CO2, 1.19 × 104 t CH4 and 589.93 t N2O in a year. The total GWP was 17.68 t CO2-eq ha?1 yr?1, of which CO2 flux was dominant (74.38%). Therefore, CO2 was the main contributor of GHGs fluxes in our study and thus future researches should focus on how to reduce CO2 fluxes from the surface of the TGR. TGR has a considerable contribution to regional GHG emissions. |