重庆金佛山岩溶区表层岩溶生态系统CO2浓度分析

以重庆金佛山林地、裸地表层岩溶生态系统CO2浓度的实际观测资料为基础,探索表层岩溶系统CO2浓度变化规律。结果显示,这种变化与土壤温度有密切关系,林地与裸地各个层次土壤的CO2浓度与土温呈一致性变化,这构成了表层岩溶生态系统对外界条件的灵敏响应。研究进一步揭示了林地植被平抑这种动态效应,而裸地则响应于温度变化。

A STUDY ON CO2 CONCENTRATION OF EPIKARST ECOSYSTEM UNDER DIFFERENT LAND-COVER IN TYPICAL REGIONS OF THE MT.JINFO

There exists variation in carbon fluxes of Epikarst. Based on the observed data at the Mt. Jinfo in Chongqing from July to August in summer of 2002, the changes of CO_2 concentration of Epikarst are analyzed. The main results are follows: 1) The change of soil CO_2 concentration related to soil temperature is clear, and it lags behind that of soil temperature in woodland and uncovered land. 2) Variation of soil CO_2 concentration related to soil temperature at 10cm and 20cm is more obvious than that at 10cm and 50cm in woodland, and is the most clear at 10cm, while that is the most unobvious at 30cm at uncovered land. 3) The change of soil CO_2 concentration related to soil temperature in woodland is more clear than that at uncovered land. 4) The change of CO_2 concentration and air temperature in vegetation-air system is obvious; and that in vegetation-air system related to its temperature is the most clear in wood. In conclusion, this investigation aims at depicting change of CO_2 concentration in Epikarst under different vegetations in summer. As compared with the significant variation of temperature of free air and of surface soil, soil temperature at different depths varies in a certain range. More gentle variation of soil temperature is found under forest than under uncovered land. The variation of CO_2 concentration is largely controlled by the soil temperature regimes. More significant variation is likely to occur in soil carbon fluxes under uncovered land due to its sensitivity to temperature changes. That illustrates sensitivity of Epikarst ecosystem to the surrounding conditions.