渤海湾典型闸控入海河流水体N_(2)O释放研究  

N_(2)O release from the water bodies of typical gate controlling tributaries of Bohai Bay

作　　者：李肖正 岳甫均 周滨[3] 王欣楚 胡健[4] 陈赛男 李思亮 LI Xiao-zheng;YUE Fu-jun;ZHOU Bin;WANG Xin-chu;HU Jian;CHEN Sai-nan;LI Si-liang(School of Earth System Science,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Earth’s Critical Zone Science and Sustainable Development in Bohai Rim,Tianjin 300072,China;Tianjin Academy of Environmental Protection Sciences,Tianjin 300191,China;Research Center for Ecology and Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China)

机构地区：[1]天津大学地球系统科学学院,天津300072 [2]天津市环渤海地球关键带科学与可持续发展重点实验室,天津300072 [3]天津市环境保护科学研究院,天津300191 [4]中国科学院生态与环境研究中心,北京100085

出　　处：《中国环境科学》2022年第1期356-366,共11页China Environmental Science

基　　金：国家自然科学基金资助项目(42073076,41925002);国家重点研发计划(2019YFC1805805);天津市科技计划项目(18ZXSZSF00130);天津大学创新基金(2021XYF-0037)。

摘　　要：为探究弱水动力条件下,典型滨海地区水体N_(2)O释放通量及其主控因素,于2019年7月和8月(夏季)和11月(冬季初期)对以大清河-独流减河-北大港湿地为代表的渤海湾弱水动力条件河流开展水样采集与分析工作.结果表明:N_(2)O浓度变化范围为0.4~184.5nmol/L,N_(2)O饱和度的变化范围为7.2%~2740%,其中近90%的样品处于过饱和状态,表明该研究区是潜在的N_(2)O释放源.N_(2)O水-气界面释放通量为-0.3~6.7μmol/(m^(2)·h),夏季水体N_(2)O的释放通量高于冬季.降雨前后N_(2)O浓度出现明显波动,相同点位降雨前后N_(2)O浓度的变化值为-15.2~63.9nmol/L,独流减河上游农业区N_(2)O浓度的平均增加量(22.1nmol/L)显著高于下游(1.3nmol/L),降雨驱动了流域氮素的运移,促进了水体N_(2)O释放.相关性分析表明,水体N_(2)O的浓度受反应物浓度、水体盐度共同调控.通过计算得到该滨海地区弱水动力条件下河流N_(2)O的排放因子为0.0073,表明气候变化委员会(IPCC)默认值0.0026可能低估了该地区间接N_(2)O释放.To explore the spatiotemporal variation in N_(2)O in typical coastal zone and its main controlling factors under weak hydrodynamic conditions,water samples were collected from coastal rivers and wetlands(Daqing River-Duliujian River-Beidagang wetland)in July and August(Summer)and November(the beginning of Winter)in 2019.The results show that the concentration of N_(2)O varied between 0.4~184.5nmol/L.The saturation of N_(2)O ranged from 7.2%~2740%,and 90%of the samples were oversaturated,indicating that the study area was a potential source of N_(2)O.The N_(2)O release flux at the water-gas interface ranged from-0.3~6.7μmol/(m^(2)·h),while the N_(2)O exchange flux in summer was higher than that in winter.The study also found that the N_(2)O concentration fluctuated significantly before and after rainfall,and the variation in N_(2)O ranged from -15.2~63.9nmol/L at same sites before and after rainfall.The average increase in N_(2)O concentration was significantly higher in the upper reaches(22.1nmol/L)than in the downstream(1.3nmol/L),indicating that rainfall drove the transportation of nitrogen species and accelerated N_(2)O release.The salinity and NO_(3)^(-)-N concentration had significant effect on N_(2)O concentration.The N_(2)O emission factor of the tributaties under the weak hydrodynamic conditions in coastal zone was estimated to be 0.0073,higher than the default value of 0.0026 defined by IPCC.Therefore,the N_(2)O budget in the coastal zone may underestimate the indirect N_(2)O emissions by using the IPCC threshold value.

关 键 词：N_(2)O 滨海地区 弱水动力河流 渤海湾 排放因子 

分 类 号：X16[环境科学与工程—环境科学]