山地岩溶湖水地球化学与碳氧同位素特征及其昼夜变化研究——以重庆金佛山药池坝湖为例  

Researches on Geochemical Characteristics of Mountain Karst Lake Water and Diurnal Variation of Carbon and Oxygen Isotopes——Case study of Yaochiba Lake,Jinfo Mountain,Chongqing

作　　者：蒋先淑 杨平恒[1,2,3] 王建力[1,2,3] 于正良[1,2] 沈蔚[1,2] 

机构地区：[1]西南大学地理科学学院,重庆400715 [2]三峡库区生态环境教育部重点实验室,重庆400715 [3]国土资源部岩溶生态环境-重庆南川野外基地,重庆408435

出　　处：《西南大学学报（自然科学版）》2016年第6期99-103,共5页Journal of Southwest University(Natural Science Edition)

基　　金：中央高校基本科研业务费专项(XDJK2014A016);2014年度重庆市国土房管科技计划项目(CQGT-KJ-2014056);重庆市自然科学基金项目(CTST2007BB7346);贵州省科技厅联合基金项目(黔科合J字LKA[2012]09号;黔科合J字LKA[2012]18号)

摘　　要：采用多参数水质分析仪,对重庆金佛山药池坝湖水的地球化学、碳氧同位素特征及其昼夜变化进行研究,结果表明:研究区湖水温度、pH值、溶解氧、电导率、δ13 CDIC和δ^(18) O等指标均表现出明显的昼夜变化规律,水温、pH值、溶解氧和δ^(13)CDIC等指标白天升高,夜间降低,电导率白天降低,夜间升高,表明湖水溶解无机碳变化过程受到物理因素和生物作用的共同影响.山地岩溶湖泊地球化学指标与δ^(13)CDIC对外界环境敏感,湖泊蒸发强烈,水体中溶解无机碳(DIC)滞留时间长,湖水与大气CO_2交换程度高,使湖水δ^(13)CDIC值偏正,接近平衡状态.湖水蒸发线斜率较小,截距较大,氢氧同位素组成主要受大气降水氧同位素组成、湖泊水-气界面蒸发过程中的同位素动力分馏效应和湖底水-岩氧同位素交换的影响.Multi-parameter water quality analyzer on-line monitoring,artificial sampling,field titration and laboratory analysis methods were applied to investigate the geochemical,carbon isotopes,oxygen isotopes characteristics and the diurnal variation of those parameters in the lake,which located at Jinfo Mountain,Chongqing.Results showed that the lake temperature,pH,dissolved oxygen,conductivity andδ13CDICsuffered significantly diurnal variation.The lake water temperature,pH,dissolved oxygen andδ13CDICindexes increased during the day and decreased during the night,which attribute to both physical and biological factors.It is found that the karst lake system is sensitive to environmental changes.In the research area,the lake has been evaporating strongly.The DIC can stay a long time in water.Meanwhile,the high extent of exchange between lake water and CO2 in the atmosphere resulted in positive value ofδ13 CDIC which reached to its equilibrium.The evaporation line of the lake was obtained,which had a lower slope and a higher intercept.Two main factors affected the isotopic composition of hydrogen and oxygen,one was the composition of oxygen isotopic from precipitation,another was isotope dynamic fractionation in lake waterair interface evaporate process and lakebed water-rock oxygen isotope exchange.Therefore,this study provided both theoretical basis for the further understanding of karst mountain lake aquatic ecosystems and the evaluation for carbon sequestration potential of aquatic plants in the lake.

关 键 词：岩溶湖泊 水化学特征 氢氧同位素 δ13 CDIC 昼夜变化 金佛山 

分 类 号：P342[天文地球—水文科学]