摘要
鄱阳湖边缘深水区是鄱阳湖水位上涨时扩散而成的低洼湖区,通过对其一典型边缘湖泊——蚌湖丰水期的氮浓度和同位素特征值的检测,分析这类洪泛湖泊在水位最高时期水体颗粒有机质及无机氮的氮同位素变化特征,并识别氮污染来源及转化途径.结果表明:6月悬浮颗粒有机质碳氮同位素值(δ^(13)C:-26.7‰^-23.7‰,δ^(15)N:2.6‰~6.2‰)介于土壤有机质(δ^(13)C:-25.21‰±0.52‰,δ^(15)N:3.79‰±0.37‰)和水生植物的碳氮同位素值(δ^(13)C:-28.8‰^-24.9‰,δ^(15)N:5.3‰~8.2‰)之间.7月相比于6月,降低的δ^(13)C(-27.6‰^-23.2‰)和升高的δ^(15)N(4.3‰~7.7‰)表明暴雨冲刷带来更多的周边陆地碎屑输入.无机氮在6月以铵态氮(NH_4^+-N)为主要形态,7月以硝态氮(NO_3^--N)为主要形态.6月δ^(15)NH_4^+较负的特征值(-18.6‰±5.2‰)表明铵态氮主要来源于雨水,硝态氮(δ^(15)NO_3^-:1.4‰±3.0‰)主要来源于农业化肥和雨水.7月相比于6月,铵态氮和硝态氮的浓度和同位素值都大幅升高(分别升高了0.3和2倍,6‰和3‰),是暴雨冲刷陆地使农业化肥、城镇生活废水和畜禽养殖废水输入的结果.水生植物的δ^(15)N在7月(8.8‰±1.1‰)相比于6月(6.6‰±1.1‰)也升高了较多,是由于水生植物吸收了更高δ^(15)N废水无机氮的结果.通过颗粒有机质和无机氮的δ^(15)N分析可知,湖区水体氮的矿化作用和硝化作用较强,藻类对湖泊的内源氮贡献较弱,沿河湖的畜禽养殖在暴雨时对水域污染的威胁较大.本研究提供了洪泛湖泊氮污染治理的科学依据.
The edge low-lying regions of are deep-water lakes when water levels rise and spread. We analyzed the changing characteristics of nitrogen stable isotope values of the particle organic matter and inorganic nitrogen during major flooding seasons in Bang Lake,one of the edge-lake of,and discriminated the origins and transformations of nitrogen pollution. The results showed that carbon and nitrogen stable isotopes value（ δ^（13）C,δ^（15）N） of suspended particle organic matter in June were-26. 7‰--23. 7‰ and 2.6‰-6.2‰,respectively,which were in the range of those of soil organic matter（-25.21‰±0.52‰ and 3.79‰±0.37‰,respectively） and those of water plant（-28. 8‰--24. 9‰ and 5. 3‰-8. 2‰,respectively）. The decreasing δ^（13）C（-27. 6‰--23.2‰） and the rising δ^（15）N（ 4.3‰-7.7‰） in July relative to June showed more terrestrial detritus input besides soil organic matter and water plant when rainstorm washes. NH_4~＋-N was main form of inorganic nitrogen in June whereas NO_3^--N was main form of inorganic nitrogen in July. The more negative δ^（15）NH_4~＋（-18.6‰±5.2‰） showed ammonia-nitrogen mainly came from rain,and nitrate-nitrogen（ δ^（15）NO_3^-： 1.4‰±3.0‰） mainly from agricultural fertilizer and rain. The concentrations and isotopic values of NH_4~＋-N and NO_3^--N had much more increasing（ 0.3 and 2 times,6‰ and 3‰,respectively） in July than June,which were possible from livelihood wastewater and livestock and poultry breeding wastewater under rainstorm washing. δ^（15）N of aquatic plant had more increasing in July（ 8.8‰±1.1‰） than June（ 6.6‰±1.1‰） due to aquatic plant absorbing high δ^（15）N of wastewater. The mineralization and nitrification of nitrogen in the lake were strong by δ^（15）N analysis,and alga made little contribution to internal nitrogen sources in flooding seasons. It was great threaten to watersheds pollution to livestock and poultry breeding along the bank of river and lake under rainstorm. This study can help to control nitrogen pollution of flooding lakes.
作者
梁越
肖化云
刘小真
胡倩倩
谢亚军
曹彦圣
丁新航
LIANG Yue;XIAO Huayun;LIU Xiaozhen;HU Qianqian;XIE Yajun;CAO Yansheng;DING Xin-hang(： Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution,State Key Laboratory Breeding Base of Nuclear Resources and Environment,School of Water Resources ＆Environmental Engineering,East China University of Technology,Nanchang 330013,P.R.China;： Key Laboratory of Poyang Lake Environment and Resource Utilization,Ministry of Education,School of Resources Envi-ronmental ＆ Chemical Engineering,Nanchang University,Nanchang 330047,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2018年第4期957-966,共10页
Journal of Lake Sciences
基金
国家自然科学基金项目(41563001)
国家重大研究与开发项目(2016YTA0601000)
东华理工大学核资源与环境国家重点实验室培育基地自主基金项目(Z1610)
东华理工大学江西省大气污染成因与控制重点实验室开放基金项目(AE1602,DHBK2015326)联合资助
关键词
碳氮稳定同位素
氮污染
鄱阳湖
蚌湖
丰水期
Carbon and nitrogen stable isotopes
nitrogen pollution
Lake Poyang
Lake Bang
flooding season
