不同水体分层对沉积物间隙水氮素垂向分布影响:以三峡水库和小湾水库为例  

Effects of Different Water Stratification on the Vertical Distribution of Nitrogen in Sediment Interstitial Waters:A Case Study of the Three Gorges Reservoir and Xiaowan Reservoir

作　　者：刘静思 朱晓声 胡子龙 张思思 杨正健[1] 纪道斌[1] 刘德富[1,2] LIU Jing-si;ZHU Xiao-sheng;HU Zi-long;ZHANG Si-si;YANG Zheng-jian;JI Dao-bin;LIU De-fu(College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,China;Hubei Key Laboratory of Ecological Restoration of River-lake and Algal Utilization,School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]三峡大学水利与环境学院,宜昌443002 [2]湖北工业大学土木建筑与环境学院,河湖生态修复与藻类利用湖北省重点实验室,武汉430068

出　　处：《环境科学》2020年第8期3601-3611,共11页Environmental Science

基　　金：国家自然科学基金项目(51879099,91647207,51779128)。

摘　　要：为分析不同分层水库沉积物间隙水氮营养盐垂向分布差异的原因,通过监测香溪河库湾、长江干流和小湾水库3种水域上覆水-间隙水环境特征,分析了不同分层水域沉积物间隙水氮营养盐垂向分布特征,并探讨了造成3种水域沉积物间隙水氮营养盐分布差异的原因.结果表明:①长江干流与香溪河库湾沉积物间隙水ρ(TN)随深度逐渐升高,而小湾水库ρ(TN)在12 cm处达到最大,底层呈"C"型分布;长江干流和香溪河库湾沉积物间隙水ρ(NH+4)随深度呈升高趋势,小湾水库底层含量略高于表层,整体上无显著变化,且长江干流与香溪河库湾ρ(NH+4)整体上高于小湾水库,浓度变化范围分别为:0.512~8.289、0.968~9.307和0.950~1.500mg·L^-1;3个水域沉积物间隙水ρ(NO-3)垂向分布特征均与ρ(NH+4)相反,且香溪河库湾与长江干流ρ(NO^-3)高于小湾水库,浓度变化范围分别为:0.143~0.674、0.107~0.647和0.050~0.051mg·L^-1;②3种水体理化指标垂向分布特征也存在明显差异.长江干流水温垂向无明显变化,垂向稳定系数N^2<5×10^-5 s^-2,水体混合均匀,溶解氧垂向变化范围为:6.180~6.318mg·L^-1;香溪河库湾中上游水温垂向上呈降低趋势,下游水温呈阶梯状分布,N2均大于5×10^-5 s^-2,处于稳定分层状态,溶解氧呈"C"型分布特征;小湾水库在水深5~15 m和54~70 m出现明显分层,溶解氧在水温梯度较大处显著降低,80 m后,沿水深无明显变化;③上覆水水动力、溶解氧分布以及沉积物环境差异是造成3种水域间隙水氮营养盐垂向分布差异的主要原因,且香溪河库湾间隙水氨氮和硝氮含量较高,可能提高反硝化速率,进而有助于水域脱氮,减少水域氮负荷.To determine the reasons for the variation in the vertical distribution of nitrogen in sediment interstitial waters between different stratified reservoirs,the characteristics of overlying water-interstitial water in Xiangxi Bay,Yangtze River mainstream,and Xiaowan Reservoir were monitored.The vertical distribution of nitrogen in sediment interstitial waters in these different stratified waters were then analyzed,and the reasons for the variation in this distribution were assessed.The results showed:①theρ(TN)in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay gradually increased with depth,while that of Xiaowan Reservoir reached its maximum at 12 cm and the bottom layer presented a"C"distribution.Theρ(NH+4)in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay exhibited an increasing trend with depth,while that of Xiaowan Reservoir was slightly higher in the bottom layer than in the surface layer,although the change with depth was not significant.Overall,theρ(NH+4)in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay was higher than that of Xiaowan Reservoir,and the concentration ranges were as follows:0.512-8.289 mg·L^-1,0.968-9.307 mg·L^-1,and 0.950^-1.450 mg·L^-1.The vertical distribution of theρ(NO-3)in the sediment interstitial waters of all three waterbodies were opposite to that ofρ(NH+4).Moreover,theρ(NO-3)in the sediment interstitial waters of Xiangxi Bay and the Yangtze River mainstream was higher than that of Xiaowan Reservoir.The concentration ranges were as follows:0.143-0.674 mg·L^-1,0.107-0.647 mg·L^-1,and 0.050-0.051 mg·L^-1.②There were also significant differences in the vertical distribution of physical and chemical indices in the three water bodies.There was no significant change in the vertical distribution of the water temperature in the Yangtze River mainstream and the N2 value was<5×10^-5 s^-2;hence,the water was well mixed,and the vertical range of the dissolved oxygen content was 6.

关 键 词：分层水库 沉积物-间隙水 氮营养盐 垂向分布 脱氮 

分 类 号：X524[环境科学与工程—环境工程]