Methane emission fluxes from seasonal flooding marshy wetland on the Zoigê Plateau during two growing seasons

To enhance our understanding of the interannual variation of methane (CH 4 ) emission on the Zoigê Plateau wetland in China and to accurately estimate CH 4 emission fluxes from the plateau wetlands, we established a standard sampling area (1 hm 2 ) of seasonal flooding marshy wetland in Zoigê wetland national nature reserve. CH 4 emission fluxes from the hummock and hollow were measured using the dark static chamber technique and Fast Greenhouse Gas Analyzer during two growing seasons in 2013 and 2014. In the 2013 growing season (June to October), the average CH 4 emission fluxes from the wetland on the hummock and hollow were 7.59 mg m -2 h -1 and 10.12 mg m -2 h -1 . In the 2014 growing season (May to October), the average CH 4 emission fluxes from wetland on the hummock and hollow were 0.62 mg m -2 h -1 and 2.74 mg m -2 h -1 . The CH 4 emission fluxes of the hummock and hollow were 12 and 4 times higher in 2013 than in 2014. The decline in CH 4 emission fluxes was probably caused by a fall in the water table level during the summer (June to August); the resulting shift to aerobic conditions could reduce the population of methanogens and stimulate CH 4 oxidation. Moreover, a marked fall in the water table level might decrease the sensitivity of the CH 4 emission flux to soil temperature, and this was evidenced by the decrease in the Q 10 values in 2014. In conclusion, in the summer, water table level is a key factor controlling methane emission flux from the seasonal flooding wetland in the Zoigê Plateau.