黑云杉林大气CO_2稳定同位素组成δ^(13)C,δ^(18)O的分析  

Analysis on Stable δ ^(13)C and δ^(18)O of CO_2 over the Boreal Black Spruce

作　　者：胡凝[1] 申双和[1] 

机构地区：[1]南京信息工程大学应用气象学系,江苏南京210044

出　　处：《南京气象学院学报》2006年第5期650-655,共6页Journal of Nanjing Institute of Meteorology

基　　金：国家自然科学基金资助项目(30370830)

摘　　要：研究CO2稳定同位素特征可以揭示光合、呼吸作用等众多信息,从而有助于了解生态系统与环境之间的碳循环过程。利用大气CO2浓度及其稳定同位素的测定资料,分析稳定同位素比1δ3C、1δ8O,发现两者具有相似的时空分布特征。主要表现在1δ3C和1δ8O在冠层内具有明显的垂直变化趋势,冠层上部重同位素含量较高,而底部含量较低。从时间变化看,1δ3C和1δ8O在午后到日落具有较高的水平,而凌晨,1δ3C和1δ8O较低。运用Keeling图法分析1δ3C、1δ8O和CO2浓度的关系,发现1δ3C值主要受光合和呼吸作用影响,与CO2浓度的高低密切相关;而1δ8O的变化比较复杂,因为1δ8O除受光合、呼吸强度影响外,还取决于环境空气湿度。Stable isotopes of CO2 can reveal much information of photosynthesis and respiration, which contributes to the understanding of the carbon cycle between ecosystem and environment. Here, using the data of CO2 concentration and its stable isotope measurements,after analyzing δ^13C and δ^18O, it is found that δ^13C and δ^18O have the similar temporally and spatially distributive characters, i. e δ^13C and δ^18O ratioes obviously vary with height, generally, the heavier/lighter isotope ratio is higher at the upper/bottom layer of canopy;and temporally, δ^13C and δ^18O ratioes are highest from afternoon to sunset,and lower before dawn,with the lowest ratio at the time when air is stable and the CO2 from the respiration of vegeta- tion and soil reaches the biggest accumulation amount. Finally, by analyzing the relation between δ^13C , δ^18Oand CO2 using the ＂Keeling Plot＂ ,and discussing the contribution of ecosystem source and sink to δ^13C and δ^18O,it is found that δ^13C is mainly affected by the concentration of CO2 ,but δ^18O is impacted by many factors,expect the concentration of CO2 ,air humidity is also an important factor.

关 键 词：黑云杉林 空气CO2 Δ^13C Δ^18O 光合作用 呼吸作用 

分 类 号：X132[环境科学与工程—环境科学]