摘要
N2O是一种重要的温室气体,土壤是全球N2O的重要排放源。通过测定土壤源N2O中N、O同位素值,可以有效识别N2O的来源途径。本文采集了南极法尔兹半岛两个地点的海豹粪土(HS和GS)、阿德雷岛两个地点的企鹅粪土(AB和AF)以及东南极的帝企鹅粪土(DQ和DQT),在室内对所采集的样品分别在有氧和厌氧条件下进行冻融培养实验。结果表明:土壤在厌氧条件下比有氧条件下排放了更多的N2O。土壤排放的N2O与当地大气N2O相比普遍贫15N和18O。除DQT和HS外,δ15N和δ18O在有氧和厌氧培养下均呈现很好的正相关性。N2O排放量下降的同时伴随着培养瓶内剩余N2O中δ15N和δ18O值的增加,证实N2O还原为N2的过程会引起重同位素富集。高的水分含量有利于土壤反硝化作用的进行,使释放的N2O气体富集重同位素;pH值也会影响N2O的同位素组成,低pH会引起δ15N值增加。
Nitrous oxide （N2O） is an important greenhouse gas, mainly emitted from soils during the nitrification and denitrification processes. Measurement of the natural abundance of N2O stable isotopes is an effective method to distinguish the N2O sources from nitrification and denitrification. In this paper, we studied the soils from Fildes Peninsula （HS and GS）, Ardley Island （AB and AF） and Emperor penguin colony （DQ and DQT） in Antarctic, and examined the isotopic compositions ofN2O through laboratory incubation experiments under N2 and under ambient air conditions, respectively. Results showed that much more N2O was formed under N2 incubation than that under ambient air incubation. For most treatments the soil emitted N2O was 15N-depleted compared to local ambient air N2O. The N2O concentration often leveled off or even decreased, accompanied by increases in δ15N and δ18O of the remaining N2O. The soil water content and pH also affect the δ15N and δ18O values.
出处
《极地研究》
CAS
CSCD
北大核心
2012年第3期215-225,共11页
Chinese Journal of Polar Research
基金
国家自然科学基金(41076124)
中国科学院知识创新工程(KZCX2-YW-QN510)
国家海洋局极地科学重点实验室开放研究基金(KP200804)
中央高校基本科研业务费专项资金(WK2060190007)资助
