摘要
氮素是影响湖泊初级生产力的主要因素之一。近年来,受气候干旱及上游用水量增加等因素的影响,大多数封闭性内陆湖都面临着湖面萎缩、湖水因营养盐浓度增加而逐渐恶化的问题。本文以内蒙古高原境内封闭型内陆湖泊——达里诺尔湖为例,于2017年夏季采集湖水、间隙水、沉积物、入湖河流等样品。对湖泊氮素赋存特征、迁移趋势做出分析,并且对入湖河流携带的氮素对湖泊水质的影响展开讨论。结果表明:氨氮(NH_4^+-N)是上覆水中占比例最高的形态氮。总氮(TN)、硝酸盐氮(NO_3^--N)、亚硝酸盐氮(NO_2^--N)含量随水深从浅到深基本保持不变。只有B6、E2、E5样点的NH_4^+-N在水深1.5 m向下处含量有所波动。表层沉积物TN均值2 809.97 mg·kg^(-1),可交换态氮占TN含量6.74%;河水中占比例最高的形态氮是NO_3^--N,四条入湖河流中,TN、NH_4^+-N含量最高的是沙里河,NO_3^--N含量最高的是亮子河;每年由入湖河流携带入湖的TN量为120 t。总体来看,达里诺尔湖氮素赋存特征为:NH_4^+-N是上覆水的主导形态氮,TN及各形态氮含量在不同深度水层掺混均匀,无明显的分层现象。沉积物TN含量较高且氮素迁移能力较强。TN、NO_3^--N、NO_2^--N表现为由沉积物到上覆水的释放状态,而NH_4^+-N则以上覆水到沉积物的吸附状态为主。河流的输入对湖水TN含量有稀释作用,但会增加湖水NO_3^--N的负荷。
Nitrogen is one of the main factors affecting the primary productivity of lakes.The Dali-Nor Lake,which is located in the middle part of the Inner Mongolian plateau,is the study lake of this research.The nitrogen occurrence characteristics and transferring trends were analyzed for samples of lake water,pore water,and sediment and water samples from the lake inlets,collected in the summer of 2017.The impacts of the different nitrogen forms on the water quality of the lake also were studied.The results showed that ammonium nitrogen(NH+4-N)was the largest component of total nitrogen(TN)in the upper layer of the lake water.TN,nitrate nitrogen(NO-3-N),and nitrite nitrogen(NO-2-N)were mixed uniformly in the lake without distinct stratification,and the TN content remained the same from the top to the bottom of the lake.The TN content in the sediments was higher,and the migration of nitrogen was stronger.TN,NO-3-N,and NO-2-N were in the re leasing state from the sediment to the upper water layer,whereas NH+4-N was mainly in the adsorption state from the upper water layer to the sediment.The input of the river had a dilution effect on the TN content of the lake water and increased the NO-3-N load of the lake water.
作者
杨旭
李畅游
李文宝
史小红
赵胜男
王旭阳
YANG Xu;LI Chang-you;LI Wen-bao;SHI Xiao-hong;ZHAO Sheng-nan;WANG Xu-yang(College of Water Conservancy and Civil Engineering,Inner Mongolia Agricultural University,Hohhot 010018,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2018年第10期2262-2269,共8页
Journal of Agro-Environment Science
基金
国家自然科学基金项目(51339002
51669022
51469025
51669002
51509133
51709162
513390020)
内蒙古自治区自然科学基金项目(2016MS0552)
中国博士后科学基金项目(204M562495XB)
自治区级创新团队项目~~
关键词
水资源保护
封闭性内陆湖
氮素
入湖河流
water resources protection
closed inland lake
nitrogen
rivers into the lake
