[Methane emission from aquatic vegetation zones of Wuliangsu Lake, Inner Mongolia]

To quantify the variations of methane fluxes from different aquatic vegetation zones, two-year measurements were measured at different aquatic vegetation zones and water depths using static chamber technique during two growing season from April to October in 2003 and 2004. Results showed that the average emission flux of CH4 from Potamogeton pectinatus (submerged macrophyte) growing zones was (3.44 +/- 1.60) mg x (m2 x h)(-1), 78.06% lower than that from Phragmites australis (emergent macrophyte). Significant seasonal and diurnal variations of CH4 emission were observed for Phragmites community; however, the variations were minor for P. pectinatus. Sediment temperature at 5 cm and photosynthesis active radiation were important factors influencing seasonal and diurnal variations of CH4 fluxes from Phragmites zone. Annual methane flux from the lake was 1 024.6 t and 1 156.7 t in 2003 and 2004, respectively.