青藏高原高寒草甸N2O排放速率及其对降水和气温的响应特征

摘要

The N2O emission fluxes from grassland ecosystem and the relationship between N2O emission fluxes and precipitation and air temperature were studied,using static chamber technique and gas chromatography,in Haibei Station of Chinese Academy of Sciences during consecutive 2 years:2013 and 2014.The results revealed that the annual mean fluxes of N2O emission rate were around 32.4±3.1μg/(m2 · h).The emission rate 41.1±4.3 μg/(m2 · h) during the growing seasons was significantly higher than that 20.2±3.2 μg/(m2 · h) during the non-growing season.The significant differences of N2O emission fluxes were found between different sampling days.The N2O emission fluxes in an alpine meadow increased with daily air temperature increasing.The relationship between fluxes of N2 O emission and precipitation was negative.The N2 O emission fluxes will increase with global warming in the alpine meadow in future.%在中国科学院海北高寒草甸生态系统定位研究站,利用静态密闭箱-气相色谱法,连续两年(2013,2014年)进行了高寒草句N2O排放速率及其对降水和气温的响应特征研究.结果表明:高寒草地N2O年平均排放速率为32.4±3.1μg/(m2·h),生长季排放速率为41.1±4.3 μg/(m2·h),明显高于休眠季的排放速率20.2±3.2 μg/(m2·h);不同采样时期N2O排放速率具有极显著差异;气温与N2O的排放速率之间存在显著正相关关系(R=0.52),随着日平均气温增加,高寒草甸土壤N2O排放速率逐渐提高;降水量与N2O排放通量之间存在较弱的负相关关系.在未来全球增温的气候情景下,高寒草地土壤N2O排放量将呈现上升的趋势.