Methane Production, Oxidation, Transport And Emission In Cyperus Malaccensis Lam. Var.Brevifolius Bocklr. Marsh Of The Min River Estuary

Soil methane production potentials of Cyperus malaccensis Lam. var. brevifolius Bocklr wetland demonstrated a distinct vertical and seasonal variaitons using two incubation methods of undisturbed soil core and soil slurry. Suppression on methane production by sulphate reduction were also showed a vertical and seasonal variations in two incubation methods. However, methane production potential and suppression of sulphate reduction measured by undisturbed soil core incubation method were higher significantly than that using slurry incubation method.The coefficient of variation of methane production potential were larger than200%both on scales of100m2and1m2, which indicating that methane production have distinct spatial variability. On the scale of100m2, spatial correlation of methane production potential were weak in spring and fall, but it was strong on the scale of1m2.Methane oxidation in the C.malaccensis wetland demonstrated a significantly monthly variation. Methane oxidation was strongest in June, and gradually declined from June to November. Methane oxidation in the C. malaccensis wetland showed a positive exponential correlation with plant net growth. Methane oxidation aiso showed a positive correlation with methane production.Methane transport and emission mediated by plant gradually declined with the flood water level increase. The plant can not transport methane when the flood water level were higher than30cm.Methane flux in the C. malaccensis wetland during flooding and ebbing stages were significantly lower than that before flood or after ebb. The differences of methane emission between before flood and after ebb were not significant. When the time the wetland soil was exposed completely increased, methane emission decreased. Methane concentration in porewater after ebb were higher than that before flood, but the differences were not significant.Tidal water brought rich SO42-and NO3-in september during tide days in spring, but SO42-concentrations in tidal water were lower than that in porewater during neap tide days in March.