The Study Of Protential Production And Oxidation Of Methane In Caohai Where Is Plateau, Wetland And Aquatic-terrestrial Ecotone

CH4 is the second largest emitter of greenhouse gases except carbon dioxide in the atmosphere. In 100 years, the greenhouse effect of single molecule of CH4 25 times higher than CO2, and a series of reactions of CH4 in the atmosphere also affect ozone concentrations.The methane concentration in the atmosphere is increased from 0.7 ppmv before the industrial revolution to the current 1.8 ppmv, the average annual increase of 0.5% to 0.8%. Wetlands are important carbon sinks, but also the emissions of greenhouse gases such as CH4, emissions account for 70% of the total natural emissions of CH4, accounting for 24.8% of total global emissions of CH4. Due to human activity and climate change, wetland hydrological conditions changed obviously, wetland water level drops. The impact of wetland hydrological conditions change and its environmental control mechanism for CH4 production and oxidation is not clear yet. In this paper, Caohai which in the Yunnan-Guizhou Plateau wetlands as the research object, CH4 produce and oxidation potential variation and its relationship for environmental factors under natural wetlands and water gradients, the findings help to understand the heterogeneity of its mechanism of wetland CH4 emissions.The main conclusions of the paper:(1) The variation of methane generation potential of Caohai wetlands under different water gradient is Farmland <native marsh <meadow <marsh meadow; the variation of methane oxidation potential is native marsh <farmland <Meadow <marsh meadow.(2) The methane gas potential of Caihai lake wetland decreases with soil depth; however, the change difference of the methane oxidation potential with depth was not significant. Wetland methane produced the most potential soil layer is 0-5cm, with other soil differ significantly(p<0.05).(3) The seasonal change of the Caihai lake wetland methane gas potential is: autumn > summer > spring > winter, and the seasonal change of methane oxidation potential is: summer > spring > winter > autumn.(4) Caohai wetland native marsh, swamp meadow soil potential to generate methane and methane oxidation potential has a significant positive correlation,meadow methane generation potential and methane oxidation potential has a significant negative correlation, farmland and its correlation is not significant.(5) The relationship with environmental factor of methane oxidation and oxidation potential environmental factors in Caohai wetland: the wetland soil temperature was of a significant positively correlation with methane production potential in farmland and methane oxidation potential in Swamp Meadows; Eh was of a significant negative correlation with methane production potential in native swamp and methane oxidation potential in swamp meadow; soil water content was of a significant positively correlation with methane production potential in swamp meadow. p H was of a significant positively correlation with methane production potential in native swamp and swamp meadow.(6) The relationship with methane production and oxidation potential of electron acceptor in Caohai wetland: The same kind of ion had an obvious difference effect on different stages of methane production and oxidation activity in Caihai wetland. The different kind of Anionic-cationic had an different effect on different kind of wet land in methane production and oxidation potential. In the cationic, Fe2+ and NH4-N had an acceleration in methane production of swamp meadow and had an effect on suppression of native swamp and meadow methane oxidation. Nitrate had the most suppression in native swamp and meadow methane oxidation. Divalent manganese ions had an acceleration on the native swamp soil methane oxidation.(7) According to principal component analysis, the main factor that had an effect on methane production and oxidation potential was soil water content, DOC, NH4-N. But the analysis of main factors explain the amount of information was not high, it showed that the main factor was in addition to environmental factors, also had the factors such as electronic by in vitro, and microbe, plant root secretion and so on.