青藏高原高寒草原碳排放及其迁移过程研究

A study on carbon fluxes from alpine grassland ecosystem on Tibetan Plateau

采用箱式法通过对青海省五道梁地区高寒草原生态系统表层土壤含碳温室气体的研究发现 ,该地区高寒草原系统表层土壤 CO2 和 CH4 在 7～ 8月份的平均排放通量分别为 0 .46μmol· m- 2 · s- 1和 - 0 .43× 1 0 - 3μmol·m- 2 ·s- 1,此两种气体的排放通量随时间都有明显的变化特征 ,它们的日变化均为明显的单峰型 ,而且其中 CO2 排放通量的变化明显受大气温度变化的影响。地下土壤中 CO2 和 CH4 气体浓度随深度的增加呈递减趋势 ,进一步的分析表明这两种气体浓度在土壤中与相邻层次的气体浓度有很明显的相关关系 ,尤以永久冻土上层边界附近最为显著。

Carbon cycle played an important role in the researches of global climate change, however, only few works on carbon dynamics from the alpine grassland ecosystem on Tibetan Plateau have been reported. Using close chamber technique, the determination of carbon emissions from the alpine grassland soil of Wudaoliang area in Qinghai Province showed that the mean fluxes of CO 2 and CH 4 from alpine grassland soil in growing season were 0.46μmol·m -2·s -1 and -0.43×10 -3μmol·m -2·s -1, respectively. The emissions of CO 2 and CH 4 demonstrated a very clear trend during the daily experiment. Both of the fluxes showed single peak during the daily variations, and air temperature had great influences on the fluxes of CO 2. The concentrations of CO 2 and CH 4 below ground decreased gradually with depth. Further analyses showed that gas concentration of one layer was exponentially related to the concentrations of its neighbor layers', especially close to the surface of permanent frozen soil.