摘要
溶解性固体总量(TDS)是水循环过程的关键示踪剂之一。特别是寒旱区,湖泊既经历冬季冰封期,也会接受夏季集中大气降水输入,这导致不同深度湖水TDS含量对应了补给源水化学特征。基于此,文中以内蒙古达里湖为目标,持续采集了2018至2020年湖水(冰)等样品共324个,系统分析了湖泊TDS含量的变化特征,并结合氢、氧稳定同位素(δD和δ^(18)O)变化,探讨了冰封-非冰封状态下补给源差异对TDS变化的影响。结果表明:1)冰封条件下冰中TDS含量较低(平均约213mg/L),对应冰体中δD和δ^(18)O值最富集(约-24.25‰和-1.22‰),而水体TDS含量相对较高(平均约483mg/L),但δD和δ^(18)O值相对贫化(约-33.56‰和-2.35‰);在非冰封期,TDS含量随水深增加小幅下降,而δD值和δ^(18)O值(平均值-32.375‰和-2.09‰)则比冬季水体更加富集。特别地,夏季湖水d-excess值明显偏负,显示大气降水等补给量增加。2)虽然达里湖水样中TDS与δD、δ^(18)O值变化过程相似,但是由于不同水深补给源以及外界环境条件差异导致于表层水主要受大气降水、河流输入和结冰过程等影响而深层水主要受地下水输入影响,因此造成表层水中TDS与同位素值相关性在非冰封阶段较低,而冰封条件下由于“冷冻浓缩”影响而相关性较高;而底层水受不同深度地下水补给过程差异影响,导致深水区(水深>7.0m)底层水TDS含量与同位素值的相关性在冰封-非冰封条件下均较高。特别地,达里湖TDS含量变化与d-excess值呈明显反相关系,指示蒸发和大气降水对湖泊水文化学特征的影响,进一步显示TDS含量变化受到水文循环过程的影响。
Total dissolved solids(TDS)is one of the key tracers for water cycle processes.Especially in cold and arid regions,lakes experience both periods of icebound in winter and concentrated atmospheric precipitation inputs in summer,which leads to the chemistry characteristics that the TDS contents at different depths of lake correspond to the different recharge sources.Based on this,in this paper,a total of 324 lake water(ice)and other samples were continuously collected from 2018 to 2020,targeting Dali Lake in Inner Mongolia,to systematically analyze the characteristics of the changes in lake TDS content,and to explore the effects of the differences in the recharge sources on the changes in TDS under the ice-covered-non-ice-covered state in conjunction with the changes in the stable isotopes of hydrogen and oxygen(δD andδ^(18)O).The results showed that:1)In icebound period,the lower TDS content(mean~213mg/L)in ice corresponded to the most enrichedδD andδ^(18)O values in the ice body(~-24.25‰and-1.22‰),whereas the water body had a relatively high TDS content(mean~483mg/L)with relatively impoverishedδD andδ^(18)O values(~-33.56‰and-2.35‰).In the non-icebound period,the TDS content decreased with a water depth decreased slightly,whileδD andδ^(18)O values(mean values-32.375‰and-2.09‰)were more enriched than in winter waters.In particular,the d-excess values of the water were significantly negative in summer,indicating that recharge from atmospheric precipitation and other sources increased.2)Although the process of TDS,δD andδ^(18)O values in Lake Dari water samples was similar,the correlation between TDS and isotope values in surface water was lower in the non-icebound period and higher in the icebound period due to the"freeze concentration"effect,while the correlation between TDS and isotope values in bottom water was higher in the deep water(water depth>7.0m)due to the difference in groundwater recharge process in different depths,which resulted in a higher correlation between TDS and isotope val
作者
张博尧
李文宝
郭鑫
史玉娇
杜蕾
ZHANG Boyao;LI Wenbao;GUO Xin;SHI Yujiao;DU Lei(Vocational and Technical College of Inner Mongolia Agricultural University,Baotou 014000;Key Laboratory of Water Utilization and Protection,Inner Mongolia Agricultural University,Hohhot 010018,China)
出处
《干旱区资源与环境》
CSCD
北大核心
2024年第8期149-158,共10页
Journal of Arid Land Resources and Environment
基金
国家自然科学基金项目(52160021)
内蒙古自然科学基金项目(2021MS05043)
内蒙古自治区科技攻关项目(2020GG0009)
内蒙古自治区高等学校“青年科技英才”项目(NJYT-20-A14)
内蒙古自治区科研项目(NJZY21502)联合资助。
关键词
TDS
氢氧同位素
补给来源
冰封期
达里湖
total dissolved solids(TDS)
hydrogen and oxygen isotopes
recharge sources
icebound period
Dali Lake
