若尔盖高原与三江平原沼泽湿地CH_4排放差异的主要环境影响因素

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

若尔盖高原沼泽湿地和三江平原沼泽湿地分别是我国面积最大的高原和平原淡水沼泽湿地。通过对二者常年积水的沼泽湿地CH4排放进行的同步观测,表明三江平原沼泽湿地CH4排放通量平均值是若尔盖高原的4.7倍。其中,若尔盖高原木里苔草沼泽的CH4排放通量范围是0.51-8.20 mg/(m2·h),平均值为2.87 mg/(m2·h);乌拉苔草沼泽CH4排放通量范围是0.36-10.04 mg,/(m2·h),平均值为4.51 mg/(m2·h)。三江平原毛果苔草沼泽湿地的CH4排放通量范围是1.32-46.38 mg/(m2·h),平均值为17.29 mg/(m2·h)。水分条件和温度条件的不同是导致两地CH4排放产生差异的主要原因。在相同的温度条件下,土壤氧化还原状况对CH4排放有重要的影响。沼泽植物的种类和数量也对沼泽湿地CH4排放具有重要的作用。

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.