骆马湖泥-水界面磷铁硫原位同步变化特征  

In situ and combined variations of phosphorus, iron and sulfur across the sediment-water interface of Lake Luoma

作　　者：林建宇 苏雅玲[1] 韩超[1] 唐皓 王兆德[1] 许笛[1] 柯凡[1] LIN Jian-yu;SU Ya-ling;HAN Chao;TANG Hao;WANG Zhao-de;XU Di;KE Fan(State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;CCCC Shanghai Dredging Co.Ltd.,Jiangsu Traffic Construction Engineering Branch,Nanjing 210000,China)

机构地区：[1]中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,江苏南京210008 [2]中国科学院大学,北京100049 [3]中交上海航道局有限公司江苏交通建设工程分公司,江苏南京210000

出　　处：《中国环境科学》2021年第12期5637-5645,共9页China Environmental Science

基　　金：国家自然科学基金资助项目(41773087458,4190071874);江苏省自然科学基金资助项目(BK20171075,BK20180109);中国科学院重点部署课题(ZDBS-LY-DQC018)。

摘　　要：利用薄膜梯度扩散(DGT)原位采样装置获取了骆马湖全湖8个典型湖区泥-水界面(SWI)活性磷(P)、铁(Fe)、硫(S)垂向分布信息,据此定量估算三者交换通量.结果表明,骆马湖沉积物剖面P、Fe、S浓度范围分别为0~2.05,0~11.10和0.01~0.63mg/L,并在微小尺度呈高度空间异质性.在水平方向上活性P、Fe主要表现为西北湖区高于东南湖区,而活性S则未表现出明显的分布规律;就垂直剖面而言,活性P、Fe、S自界面向下呈升高趋势,并在60mm深度内出现峰值,且活性P和Fe剖面呈明显的同步变化特征;活性P、Fe在多数点位具有显著的正相关性(r>0.65,P<0.01),且各采样点沉积物中的总铁与总磷比值[w(ΣFe)/w(ΣP)]均高于15,这表明Fe的地球化学循环过程对于骆马湖内源磷释放起重要控制作用;8个采样点样品中活性P、Fe、S交换通量分别为0.066~0.698,1.671~5.592和0.007~0.071mg/(m^(2)·d),表明P、Fe、S由沉积物向水体释放.西北湖区表现出较高的P通量和活性P浓度,这可能会增加南水北调过程中水质污染的风险,应予以重视.以上结果支持了P、Fe耦合释放机制,明确了骆马湖SWI的活性P、Fe、S迁移特征.This study firstly obtained 8 typical profiles of labile phosphorus(P),iron(Fe),and sulfur(S)in the sediments of Lake Luoma using the in situ,diffusive gradients in thin films(DGT)technology,and then quantitatively calculated the combined fluxes of P,Fe and S across the sediment-water interfaces(SWI).Our results demonstrated that highly heterogeneous distributions of DGT-measured labile P,Fe and S in the sediment profiles,with the concentration ranges from 0 to 2.05mg/L,0 to 11.10mg/L and 0.01 to 0.63mg/L,respectively.Generally,the concentrations of labile P and Fe in the northwest lake area were higher than those in the southeast lake area,while the variations of labile S showed no significant regularity.For all the profiles collected,the variations of labile P,Fe,and S exhibited a similar shape reflected by downward increases in concentration with sediment depth,and appear concentration peaks were observed within 60mm depth.Moreover,there was a significant positive correlation(r>0.65,P<0.01)between labile P and Fe,and the ratio of total iron to total phosphorus[w(ΣFe)/w(ΣP)]was higher than 15,which disclosed that the geochemical cycle of Fe played an important role in controlling the release of endogenous phosphorus in Lake Luoma;The fluxes of labile P,Fe and S across the SWI were 0.066~0.698mg/(m^(2)·d),1.671~5.592mg/(m^(2)·d)and 0.007~0.071mg/(m^(2)·d),respectively,indicating that P,Fe and S of Lake Luoma were released from sediments to water.It may increase the risk of water pollution during the South-to-North Water Diversion and accordingly should be taken seriously.The above results supported the coupled release mechanism of P and Fe,and clarified the migration characteristics of active P,Fe and S in SWI of Lake Luoma,providing reference and theoretical basis for water quality control of Luoma Lake.

关 键 词：泥-水界面 铁-磷-硫循环 原位 高分辨 交换通量 薄膜梯度扩散(DGT) 

分 类 号：X524[环境科学与工程—环境工程]