Association between CH_(4)uptake and N_(2)O emission in grassland depends on nitrogen inputs  

氮添加对草地生态系统CH_(4)吸收与N_(2)O排放耦合关系的影响

作　　者：Yiming Ren Yangxinzi Zao Ying Zhao Rui Su Guowei Yang Xiran Li Jingru Kang Yiyu Shi Yuru Xie Nannan Wang Yunjiang Zuo Kexin Li Liyuan He Xiaofeng Xu Lihua Zhang 

机构地区：[1]College of Life and Environmental Sciences,Minzu University of China,Beijing 100081,China [2]College of Science,Minzu University of China,Beijing 100081,China [3]College of Fine Arts,Minzu University of China,Beijing 100081,China [4]Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun 130102,China [5]Biology Department,San Diego State University,San Diego,CA 92182,USA [6]State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Beijing 100093,China

出　　处：《Journal of Plant Ecology》2024年第6期170-183,共14页植物生态学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(32271681);by Key Laboratory of Ecology and Environment in Minority Areas(Minzu University of China),National Ethnic Affairs Commission(KLEEMA202206).

摘　　要：Increasing nitrogen(N)input has been recognized as one of the important factors influencing methane(CH_(4))uptake and nitrous oxide(N_(2)O)emission in arid and semiarid grasslands.Numerous studies have examined the spatiotemporal variations of CH_(4)and N_(2)O fluxes in various ecosystems;however,the variation of the interplay between CH_(4)uptake and N_(2)O emission with increasing N has not yet been well understood.This study explored the relationship between CH_(4)uptake and N_(2)O emission in a semiarid grassland in Inner Mongolia,northern China,under a gradient of 12-year N additions.We found a synergistic relationship at low-N levels,where CH_(4)uptake and N_(2)O emission are positively correlated.Conversely,an antagonistic interaction emerged with a negative correlation between CH_(4)uptake and N_(2)O emission observed at high-N levels,which was evidenced by a 33.62%decrease in CH_(4)uptake and a 264.91%increase in N_(2)O emission.Further independent analysis,covering at least five N addition levels across grassland ecosystems in China,confirmed the general pattern:three of four cases showed a synergistic relationship at low-N levels and an antagonistic relationship at high-N levels.Given the increasing N deposition in the future,the dynamics between CH_(4)uptake and N_(2)O emission are critical for understanding the impact of external N input on net greenhouse gas emission and consequent global climate change.氮(N)输入增加是影响干旱和半干旱草地甲烷(CH_(4))吸收和氧化亚氮(N_(2)O)排放的重要因素之一。已有大量研究探讨了不同生态系统中CH_(4)和N_(2)O通量的时空变化,但尚不清楚CH_(4)吸收和N_(2)O排放之间的耦合关系随着N输入的增加如何变化。本研究依托中国北部内蒙古半干旱草原地区开展了连续12年的N添加实验平台,探讨CH_(4)吸收与N_(2)O排放之间的耦合关系。研究结果表明,CH_(4)吸收和N_(2)O排放在低N添加条件下呈现正相关的协同关系;在高N添加条件下,呈现负相关的拮抗关系,具体表现为CH_(4)吸收减少了33.6%,N_(2)O排放增加了264.9%。中国草地生态系统至少5个N添加水平实验的独立分析证实了这一普遍规律:4个N添加实验中,有3个在低N水平上表现出协同关系,在高N水平上表现出拮抗关系。考虑到未来N沉降会增加,本研究中观察到的CH_(4)吸收与N_(2)O排放之间耦合关系的变化对于理解外源N输入对温室气体净排放及其对全球气候变化的影响至关重要。

关 键 词：CH_(4)uptake N_(2)O emission N addition Coupling relation Semiarid grasslands 

分 类 号：O57[理学—粒子物理与原子核物理]