Influence of Major Environmental Factors on Difference of Methane Emission from Zoige Plateau and Sanjiang Plain Wetlands

Now the global climate change is a serious environmental problem in the world. Methane as an important green house gas, its concentration in the global troposphere is increasing. Based on IPCC, atmospheric concentration of methane has been increased to 1.745ppm in 1998. Wetland is a major source of methane e-mission. China has an area of about 2.5 × 105km2 of wetland, in addition, of all the countries with wetland in the world, only China has plateau wetland, so studying methane emission from China's wetland and influence of its major environmental factors on it is of great importance to estimating the global budget of methane emission. Zoige Wetland is the largest plateau wetland and Sanjing Wetland is the largest plain wetland in China. The methane emission flux from the two wetlands were concurrently monitored from May to September in 2001. CH4 emission flux from the Carex muliensis wetland in Zoige Wetland was 0.51 - 8.20 mg/(m2·h), average 2.87 mg/(m2·h), and from the Carex meyeriana wetland in Zoige Wetland was 0.36- 10.04 mg/ (m2·h), average 4.51 mg/(m2·h) and from the Carex lasiocarpa wetland in Sanjiang Wetland was 1.32-46.38 mg/(m2·h), average 17.29 mg/(m2·h). Because of difference of water and temperature condition, the average value of CH4 emission flux from Sanjiang Wetland was 4.7 times as more as that from Zoige Wetland. At the same temperature, Eh of soil is an important influence factor to methane emission from wetlands. Character and density of plants are also some factors that affect CH4 mission from wetland.