青藏高原冻土区湿地甲烷排放及同位素特征研究

Research on the Methane Emission and Carbon Isotope of Permafrost Wetland in Qinghai-Tibet Plateau

青藏高原冻土区是我国最重要的湿地分布区之一,其碳循环系统在陆地生态环境中具有重要的作用。为了系统地研究青藏高原冻土区湿地甲烷排放特征,采用静态箱采气法,通过对近地表游离气甲烷碳同位素含量进行现场测定;结合吸附气烃类气相色谱分析,利用已有的天然气气源判别图解,对研究区甲烷气源成因进行判别。结果显示,在青藏高原冻土区木里地区,土壤甲烷排放在春季最高,以生物成因为主,夏季为混合成因,秋季较低,且以热成因为主,生物作用是影响该区甲烷排放的主要因素,同时地下天然气水合物中的气体逸散作用也在一定程度上影响了研究区地表甲烷浓度。

As one of the most important wetland area component,carbon cycle in Qinghai-Tibet Plateau plays a critical role in the terrestrial ecosystem.For systematically studying the methane emission of permafrost wetland in Qinghai-Tibet Plateau,by using the chamber method,we made a field measurement on the methane carbon isotope.Furthermore,combining with the adsorbed gas chromatography result,we conducted the gas source discrimination.The results show that the soil methane emission is the highest and mainly on biogenic source in spring.In summer,methane of soil emission is mainly on mixed-genetic source.In autumn,the soil methane emission is the lowest and mainly on thermo genic gas.The biological action is the main influence factor of methane emission.Meanwhile,the gas escaped from the natural gas hydrate underground also influenced the atmospheric methane content to some extent.