Lin Qing, Jin Huijun, Cheng Guodong, Li Ning
Research on emmission of greenhouse gases from permafrost surface has been of importance and concerns recently in the study of global climatic and environmental change. We sampled and measured gas emmitted from a dry meadow in permafrost area in Wudaoliang in the Tibetan Plateau, with a static chamber method. The concentration of CH4 in the chamber is from 0.63 to 1.54 μg/g, with an average of 1.19 μg/g, which are lower than 1.32 μg/g, the local atmospheric mathane concentration. And those of CO2 vary from 0.15% to 0.27%, with an average of 0.21%, which are obviously higher than 0.069%, the atmospheric CO2 concentration. Both CH4 and CO2 concentrations have their diurnal variations, with their peaks occuring in the evening(20:00)and the morning(8:00), respectively Emmission rate of CH4 ranges from-0.032 to 0.048 mg·m-2·h-1, with an average of 0.001 mg·m-2·h-1 While that of CO2 ramges from-56.503 to 61.425 mg·m-2·h-1, with an average of 0.095 mg·m-2·h-1 These results coincide with the fact that methane is produced by bacterial activities in wet soil and consumed by the ways of photochemical reactions and oxidation, and that carbon dioxide is produced by the biotic respiration in strongly radiative and dry plateau. Based on the concentrations of CH4 and CO2, we suggest that the dry meadow in the permafrost area is a source of CH4 and a sink of CO2, respectively.
