土地利用对句容河氧化亚氮溶存浓度与排放的影响  

Impact of Land Use on the Concentration and Emissionof Nitrous Oxide in Jurong River

作　　者：马巍 章文诗[3] 李玉红 蒋浩 MA Wei;ZHANG Wenshi;LI Yuhong;JIANG Hao(School of Ecology and Environment,Tibet University,Lhasa 850000,P.R.China;Key Laboratory of Aquatic Plants andWatershed Ecology,Chinese Academy of Sciences,Wuhan 430074,P.R.China;School of Earth System Science,Tianjin University,Tianjin 300072,P.R.China;Hubei Provincial Key Laboratory ofWetland Evolution and Ecological Restoration,Wuhan 430074,P.R.China;DanjiangkouWetland Ecosystem Field Scientific Observatory,Wuhan 430074,P.R.China)

机构地区：[1]西藏大学生态环境学院,西藏拉萨850000 [2]中国科学院水生植物与流域生态重点实验室,湖北武汉430074 [3]天津大学地球系统科学学院,天津300072 [4]湿地演化与生态恢复湖北省重点实验室,湖北武汉430074 [5]丹江口湿地生态系统野外科学观测研究站,湖北武汉430074

出　　处：《水生态学杂志》2025年第2期13-21,共9页Journal of Hydroecology

基　　金：国家自然科学基金(32030069,U23A2048);湖北省科技计划项目(2023AFB811);广西科技攻关项目(AB24010128)。

摘　　要：揭示土地利用对河流氧化亚氮(N_(2)O)浓度与排放的影响,为提高全球温室气体模型估算的准确度,制定减排政策提供参考。2022年7月在句容河采集了河水和沉积物样品,测量了相关水体和沉积物理化因子,并测定了河流N_(2)O溶存浓度和水-气界面排放速率,探讨了缓冲区、河岸带和集水区3个不同尺度的土地利用对河流N_(2)O产生与排放的影响。结果表明,句容河夏季N_(2)O的平均浓度为10.11 nmol/L,近岸位置的平均排放速率为1.66μmol/(m^(2)·h),河中位置的平均排放速率为1.28μmol/(m^(2)·h),浓度与排放速率均低于全球平均水平[37.50nmol/L;4.01μmol/(m^(2)·h)]。句容河N_(2)O的浓度和排放与河流级别没有显著的关系,而更多受流域内人类活动尤其是农业活动和城市化的显著影响。污水输入的氮、碳等营养盐显著改变了河流内部氮素的生物地球化学循环过程,进而影响了N_(2)O的产生与排放。不同人类活动类型在不同空间尺度上对句容河N_(2)O产生具有显著影响,以点源污染为主的城镇和城市(不透水地表)在较大尺度上(河岸带与集水区)影响较为明显(P=0.1),而在缓冲区这种小尺度范围内,农田的影响较为明显(P=0.09)。Exploring the impact of land use on the concentration and emission of nitrous oxide(N_(2)O)in rivers is pivotal for understanding the broader impacts of human activities on global climate change.The Jurong River catchment in Jiangsu Province,a sub-shed in the Yangtze River basin,is severely affected by human activities,making it an ideal site for studying the impact of human activities and land-use change on the concentration and emission of N_(2)O in rivers.In July 2022,water and sediment samples at 18 sampling sites across the Jurong River watershed were collected for determination of physicochemical factors.Emission rates of N_(2)O at the water-air interface were measured near-shore and river-center at each site,and the effects of land use on N_(2)O concentrations and emissions were explored at three different scales(500 m radius,riparian zone,and catchment area).The average concentration of dissolved N_(2)O in the Jurong River was 10.11 nmol/L in summer,and the average emission rates were 1.66μmol/(m^(2)·h)near-shore and 1.28μmol/(m^(2)·h)river-center,lower than the global average concentration of 37.5 nmol/L and emission rate of 4.01μmol/(m^(2)·h).The concentration and emission of N_(2)O in Jurong River did not exhibit significant correlation with river scales,but were markedly influenced by agriculture and urbanization within the watershed.The N_(2)O emission near-shore was positively correlated with the NO_(3)^(-)concentration(P=0.1),and the NO_(3)^(-)concentration was positively correlated with concentrations of Cl-(P=0.05)and SO_(4)^(2-)(P<0.05),implying that domestic wastewater increased N_(2)O emission.However,the correlations of N_(2)O concentration with Cl-and SO_(4)^(2-)concentrations were not significant,implying that direct input of N_(2)O from domestic wastewater was not likely.Nutrient input,including nitrogen and carbon,from wastewater significantly alter biogeochemical cycling of nitrogen within the river,consequently affecting N_(2)O production and emission.Different human activities si

关 键 词：氧化亚氮 土地利用 空间尺度 句容河 

分 类 号：X52[环境科学与工程—环境工程]