摘要
陆地风化的硫酸盐(SO_(4)^(2-))通过河流体系输入海洋,其通量以及硫酸盐同位素组成(δ^(34)S_(SO4)和δ^(18)O_(SO4))对全球硫循环及海洋SO_(4)^(2-)同位素组成至关重要.河流体系SO_(4)^(2-)含量及δ^(34)S_(SO4)和δ^(18)O_(SO4)组成不但受SO_(4)^(2-)来源控制,而且受河流内部硫酸盐细菌还原及氧化过程影响,但其影响程度仍不明确,特别是拦河筑坝以及水沙调控过程对流域硫循环的影响仍不清楚.选择黄河小浪底水库作为研究对象,借助水化学、水体氢氧同位素(δD_(H2O)和δ^(18)O_(H2O))及δ^(34)S_(SO4)和δ^(18)O_(SO4)方法,通过对比分析水沙调控前后下泄河水SO_(4)^(2-)含量及同位素组成差异,阐明水沙调控过程对河水SO_(4)^(2-)通量及同位素组成的影响机制.结果表明:(1)2018年黄河小浪底水库水沙调控发生在7月份,8月份泥沙下泄与中游黄土高原降雨有关.两次排沙过程下泄水δ^(18)O_(H2O)均值分别为-8.1‰和-8.9‰,SO_(4)^(2-)均值分别为1.43 mmol/L和1.77 mmol/L,δ^(34)S_(SO4)均值分别为8.3‰和7.4‰,δ^(18)O_(SO4)均值分别为5.4‰和5.7‰.(2)水沙调控开始前(6月份)下泄河水δ^(18)O_(H2O)均值为-7.0‰,SO_(4)^(2-)均值为1.59 mmol/L,δ^(34)S_(SO4)均值为8.0‰,δ^(18)O_(SO4)均值为7.5‰;水沙调控结束后(10月份)下泄河水δ^(18)O_(H2O)均值为-9.2‰,SO_(4)^(2-)均值为1.26 mmol/L,δ^(34)S_(SO4)均值为6.7‰,δ^(18)O_(SO4)均值为7.3‰.(3)黄河小浪底水库7月份水沙调控导致泥沙暴露,有机硫和来自硫酸盐细菌还原产生的硫化物发生氧化,造成下泄河水δ^(18)O_(SO4)值降低,但下泄河水在下游河道内流动过程中δ^(34)S_(SO4)和δ^(18)O_(SO4)变化不大.(4)2018年黄河小浪底水文站SO_(4)^(2-)输出通量为0.061 Tmol/a,水沙调控过程SO_(4)^(2-)输出通量占全年SO_(4)^(2-)输出通量的比例为14.8%,入海δ^(34)S_(SO4)和δ^(18)O_(SO4)流量均值分别为7.6‰和6.8‰.黄河排沙过程改变原有水-沉积物界面环
Weathering‐derived sulfate(SO_(4)^(2-))from the Continent could be transported to the Ocean by river systems,and sulfate flux coupled with sulfur and oxygen isotope compositions(δ^(34)S_(SO4)andδ^(18)O_(SO4))were vital to the global sulfur cycling and sulfate isotope compositions in ocean.SO_(4)^(2-)contents together withδ^(34)S_(SO4)andδ^(18)O_(SO4)values were not only controlled by SO_(4)^(2-)sources,but affected by sulfate bacterial reduction(SBR)in internal riversystem,however,these effects were still unclear,and particularly the influences from dam and water‐sediment regulation scheme(WSRS)on sulfur cycling in watershed were still unknown.The Xiaolangdi Reservoir in the Yellow River was selected to solve this problem,and hydrochemical compositions,water isotope compositions(δD_(H2O)andδ^(18)O_(H2O)),andδ^(34)S_(SO4)andδ^(18)O_(SO4)were determined to constrain the effects of WSRS on riverine sulfate flux and isotope compositions by comparing the SO_(4)^(2-)contents and isotope compositions before and after the WSRS.The results indicated that(1)WSRS occurred in July 2018,sediment discharge in August was due to sediment scoured by precipitation in midstream of Yellow River.The discharged river water during these two sediment removal had averageδ^(18)O_(H2O)values of-8.1‰and-8.9‰,and average SO_(4)^(2-) concentrations of 1.43 mmol/L and 1.77 mmol/L,and averageδ^(34)S_(SO4)values of 8.3‰and 7.4‰,and averageδ^(18)O_(SO4)values of 5.4‰and 5.7‰,respectively.(2)The dischared river water before the WSRS(June)had positive averageδ^(18)O_(H2O)value of-7.0‰,moderate average SO_(4)^(2-)concentration of 1.59 mmol/L,positive averageδ^(34)S_(SO4)andδ^(18)O_(SO4)values of 8.0‰and 7.5‰,resepectively.The dischared river water after the WSRS(October)had negative averageδ^(18)O_(H2O) value of-9.2‰,low average SO_(4)^(2-) concentration of 1.26 mmol/L,negative averageδ^(34)S_(SO4)value of 6.7‰and positive averageδ^(18)O_(SO4)value of 7.3‰,respectively.(3)The WSRS in July resulted in the
作者
张东
朱双双
赵志琦
李玉红
杨锦媚
段慧真
郭文静
刘运涛
Zhang Dong;Zhu Shuangshuang;Zhao Zhiqi;Li Yuhong;Yang Jinmei;Duan Huizhen;Guo Wenjing;Liu Yuntao(School of Resource and Environment,Henan Polytechnic University,Jiaozuo 454000,China;School of Earth Science and Resources,Chang'an University,Xi'an 710054,China;The Fifth Institute of Geo-Exploration,Henan Bureau of Geo-Exp Loration&Mineral Development,Zhengzhou 450001,China;Henan Province Research Center on Applied Engineering Technology of Hydrogeology,Zhengzhou 450001,China)
出处
《地球科学》
EI
CAS
CSCD
北大核心
2022年第2期589-606,共18页
Earth Science
基金
国家自然科学基金项目(Nos.42073009,41930863,41573095)
河南省地质矿产勘查开发局青年科技创新项目(No.豫地矿青科创[2020]8号)。
关键词
硫酸盐
硫和氧同位素
黄河小浪底水库
水沙调控
硫循环
水文地质
sulfate
sulfur and oxygen isotopes
Xiaolangdi reservoir in the Yellow River
water-sediment regulation scheme
sulfur cycling
hydrogeology
