植物生态学报 ›› 2018, Vol. 42 ›› Issue (1): 105-115.DOI: 10.17521/cjpe.2017.0164

• 研究论文 • 上一篇    下一篇

土壤含水量调控高寒草原生态系统N2O排放对增温的响应

王冠钦1,2,李飞1,2,彭云峰1,陈永亮1,韩天丰1,杨贵彪1,2,刘莉1,2,周国英3,杨元合1,2,*()   

  1. 1中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093
    2中国科学院大学, 北京 100049
  • 出版日期:2018-01-20 发布日期:2018-01-18
  • 通讯作者: 杨元合
  • 基金资助:
    国家自然科学基金(41371213);国家自然科学基金(41501265)

Responses of soil N2O emissions to experimental warming regulated by soil moisture in an alpine steppe

WANG Guan-Qin1,2,LI Fei1,2,PENG Yun-Feng1,CHEN Yong-Liang1,HAN Tian-Feng1,YANG Gui-Biao1,2,LIU Li1,2,ZHOU Guo-Ying3,YANG Yuan-He1,2,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China

    2University of Chinese Academy of Sciences, Beijing 100049, China; and 3Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810008, China
  • Online:2018-01-20 Published:2018-01-18
  • Contact: Yuan-He YANG
  • Supported by:
    Supported by the National Natural Science Foundation of China(41371213);Supported by the National Natural Science Foundation of China(41501265)

摘要:

土壤氧化亚氮(N2O)排放是大气N2O不可忽视的来源。然而, 目前学术界在气候变暖对土壤N2O排放影响方面的认识仍存在较大争议, 且调控土壤N2O排放的微生物机制尚不明确。为此, 该研究以青藏高原高寒草原生态系统为研究对象, 使用透明开顶箱(OTCs)模拟气候变暖, 并基于静态箱法测定了2014和2015年生长季(5-10月)的土壤N2O通量, 同时利用定量PCR技术测定了表层(0-10 cm)土壤中氨氧化古菌(AOA)和氨氧化细菌(AOB)的基因丰度。结果显示: 增温处理导致2014和2015年生长季表层(0-10 cm)土壤温度分别升高了1.7 ℃和1.6 ℃, 土壤体积含水量下降了2.5%和3.3%, 其他的土壤理化性质没有发生显著变化。土壤N2O通量呈现年际差异, 2014和2015年生长季的平均值分别为3.23和1.47 μg·m -2·h -1, 然而, 增温处理并没有显著改变土壤N2O通量。2014年生长季主导硝化作用的AOA和AOB的基因丰度分别为5.0 × 10 7和4.7 × 10 5拷贝·g -1, 2015年为15.2 × 10 7和10.0 × 10 5拷贝·g -1。尽管基因丰度存在显著的年际差异, 但在两年中与对照相比并未发生显著变化。在生长季尺度上, 增温导致的土壤N2O变化量与其引起的土壤水分变化量之间显著正相关, 而与土壤温度的变化量之间没有显著相关关系。以上结果表明, 增温导致的土壤干旱会抑制土壤N2O通量对增温的响应, 意味着未来评估气候变暖情景下土壤N2O排放量时需考虑增温引发的土壤干旱等间接效应。

关键词: 气候变暖, 氧化亚氮, 氨氧化古菌, 氨氧化细菌, 青藏高原

Abstract:

Aims Nitrous oxide (N2O) is one of the most important greenhouse gases, which contributes a lot to global warming. However, considerable variations are observed in the responses of soil N2O emissions to experimental warming, and the underlying microbial processes remain unknown.

Methods A warming experiment based on open-top chambers (OTCs) was set up in a typical alpine steppe on the Qinghai-Xizang Plateau. The static chamber combined gas chromatography method was applied to investigate soil N2O flux under control and warming treatments during the growing seasons in 2014 and 2015. Gene abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were quantified using quantitative real-time PCR.

Important findings Our results showed that the warming treatments increased soil temperature by 1.7 and 1.6 °C and decreased volumetric water content by 2.5% and 3.3% respectively during the growing season (May to October) in 2014 and 2015. However, there were no significant differences in other soil properties. Our results also revealed that, the magnitude of soil N2O emissions exhibited substantial variations between the two experimental years, which were 3.23 and 1.47 μg·m -2·h -1in 2014 and 2015, respectively, but no significant difference in N2O fluxes was observed between control and warming treatments. AOA and AOB abundances are 15.2 × 10 7and 10.0 × 10 5copies·g -1 in 2014, and 5.0 × 10 7and 4.7 × 10 5copies·g -1in 2015, with no significant differences between control and warming treatments during the experimental period. Furthermore, warming-induced changes in N2O emissions had no significant relationship with the changes in soil temperature, but showed a significant positive correlation with the changes in soil moisture at seasonal scale. Overall, these results demonstrate that soil moisture regulates the responses of N2O emissions to experimental warming, highlighting the necessity to consider the warming-induced drying effect when estimating the magnitude of N2O emissions under future climate warming.

Key words: climate warming, nitrous oxide, ammonia-oxidizing archaea, ammonia-oxidizing bacteria, Qinghai-?Xizang Plateau