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1.
内蒙古高原达里诺尔湖夏季水体稳定同位素变化特征 总被引：4，自引：2，他引：2
基于内蒙古高原寒-旱区达里诺尔湖（简称"达里湖"）相对集中的夏季大气降水、强烈的蒸发作用等典型区域气候环境特征，结合湖泊水体温度、盐度等理化指标变化，对夏季达里湖湖水、入湖河水、区域大气降水等样品中稳定氢、氧同位素（δD、δ18O）值变化进行了对比分析.结果显示：虽然整体上达里湖夏季水体并没有形成明显的物理性质"跃层"（如温跃层、盐跃层等），水体理化指标的空间分布相对稳定，但是夏季湖水中δD、δ18O值却随着水深增加逐渐偏负：δD值由表层水体（0~1 m）到底层水体（7~9 m）偏负约1.40‰，δ18O值由表层水体到底层水体偏负约0.27‰.达里湖夏季"大气水线"为δD=8.22δ18O+6.82，显示大气降水中δD、δ18O值受季风降水效应影响的同时受到区域蒸发作用影响.特别是7、8月大气降水同位素变化受降水效应的影响比6、9月更明显，而6、9月大气降水同位素变化受蒸发作用的影响比7、8月更明显.这也导致达里湖夏季上层水体受大气降水的稀释作用影响显著；伴随水深的增加，降水效应及蒸发作用的混合影响逐渐减弱，底层水体受区域地下水补给过程等因素的影响则可能更加明显，即达里湖夏季上层水体和底层水体中稳定同位素组成变化的影响因素存在差异. 相似文献
2.
新疆艾比湖主要入湖河流同位素及水化学特征的季节变化 总被引：2，自引：1，他引：1
通过野外调查取样和室内测试分析，利用水文化学以及氢氧稳定同位素技术，分析艾比湖主要入湖河流氢氧同位素及水化学的组成特征，并探讨其季节性变化.结果表明：地表水水质指标高值多出现于博乐市、温泉市和精河县及艾比湖湿地附近，主要污染为水体富营养化、工矿业污染以及有机质污染，其污染程度夏、秋季高于春、冬季.河水的δ18O与δ2H存在明显的线性关系，其相关指数为夏季（R2=0.99） > 春季（R2=0.98） > 秋季（R2=0.96） > 冬季（R2=0.90），均沿当地大气降水线分布，受西北干旱区强烈的蒸发作用影响，各季节河流斜率均小于8，氘过量参数值多为正值.博尔塔拉河与精河地表水体δ18O值整体上表现为沿流程逐渐偏正的趋势，博尔塔拉河水体氢氧同位素与高程相关指数表现为春季（R2=0.70） > 冬季（R2=0.57） > 夏季（R2=0.45） > 秋季（R2=0.30），精河因其海拔差异不大，流程简短，与高程相关性低.博尔塔拉河和精河氢氧同位素与氯化物、硫酸盐、五日生物需氧量等指标间存在相关性，且在夏、秋季最大，相关系数R>0.75，与总磷、Cu2+、色度、浊度等指标基本都不显著相关，相关系数R<0.25. 相似文献
3.
通过测量辽宁省鞍山-海城地区地震重点监测区地下水离子浓度和氢、氧同位素组成，讨论了该区地下水化学类型的时空变化及其成因。测量结果表明，取样点水温变化范围为11.0～97.0℃，水样的总固溶物（TDS）在197.89～829.99mg/L之间，水样分为8种化学类型。大部分水样的δD、δ18O值均沿中国东北地区大气降水线分布，少数有所偏离，表明该区的地下水主要接受大气降水的补给，并可能有深部水的供给。研究区Ca-HCO3和Ca·Mg-HCO3型水主要是岩石风化溶解和阳离子交换作用的结果；Ca-HCO3·Cl和Ca·Na-Cl·SO4型水主要受岩石风化溶解、阳离子交换作用、深部卤水混入或人类活动影响；Ca-HCO3·SO4和Ca-SO4·HCO3型水与岩石风化溶解以及深部流体混入有关；Na-SO4·HCO3和Na-HCO3·SO4型水主要是深部来源水体的混入造成的。采样期间研究区发生2次ML≥3.0地震，采样点在地震发生月份出现了明显的离子浓度异常变化；Na+、Mg2+、Ca2+、Cl-和SO42-浓度变化明显，对地震活动响应较灵敏。 相似文献
4.
盐分是参与湖泊物质循环的重要成分之一，湖泊盐度增加对湖泊生态系统健康造成了严重的威胁.乌梁素海总溶解性固体（TDS）和盐度均处于较高的水平，为揭示盐分在冰-水-沉积物中的分布及迁移规律，冰封期在乌梁素海7个采样点采集冰、冰下水和不同深度沉积物样品，分析样品的TDS、Na+和Cl-浓度，得到各自在冰-水间浓度的比值，即分配系数K，并对水-沉积物界面Na+和Cl-的扩散通量进行估算.结果显示，TDS、Na+和Cl-在冰-水中分配系数K的均值分别为0.02、0.03和0.01，表明在湖水结冰形成冰盖的过程中，随着冰晶的析出，TDS、Na+和Cl-逐渐在水体中浓缩，水体中Na+和Cl-在浓度梯度驱动力作用下，向沉积物间隙水中扩散，估算其扩散通量均值分别为-229和-676 mg/（m2·d）.总之，湖水在冻结过程中，由于冰晶的析出，盐分向冰下水体中迁移，使得盐分浓度在冰下水体中浓缩增加，继而向沉积物中迁移，对湖泊水生态环境构成胁迫. 相似文献
5.
统计分析了青藏高原不同区域水体环境表层沉积物陆相介形类的属种分布特征,探讨了介形类在不同水环境下（盐度、pH值及水深）对生态环境的响应.结果显示,青藏高原现生介形类共计21属67种,其中Candona candida、Ilyocypris bradyi、Eucypris inflata、Limnocythere dubiosa、Limnocythere inopinata、Paracypricerus angulata、Leucocytherella sinensis和Leucocythere mirabilis为青藏高原地区的常见种.湖泊、河流、洼地和湿地4类水体环境中,湖泊中介形类最为丰富,达19属62种;青藏高原东北部（祁连山和柴达木盆地）、北部（昆仑山）、西部和南部不同区域的介形类常见种存在较大差异,可能是区域海拔、pH值和盐度综合作用的结果.淡水和微咸水环境介形类属种数量较咸水及盐湖中丰富,分别有17属41种和13属42种,Limnocythere dubiosa （0.52~90.6 g/L）和Leucocythere mirabilis（0.51~174.63 g/L）在淡水、咸水及盐湖中均有出现,适应盐度范围较广;pH值在8.0~10.0范围内介形类属种多样性最丰富,表明大部分介形类具有嗜碱性的特征;青藏高原陆相介形类属种多样性随水深的增加而降低,浅湖（0~15 m）中介形类属种最为丰富,达到17属52种,其中Candona candida（0.2~80 m）和Leucocythere dorsotuberosa（0.3~110 m）从滨湖至深湖区均有分布,二者均具有较大的水深适应范围. 相似文献
6.
三峡水库与长寿湖水库鱼类碳、氮稳定同位素特征及营养级的比较 总被引：1，自引：0，他引：1
为探究人为活动对水库鱼类食物来源和营养级关系的影响，选择人为影响程度较低的三峡水库和影响程度较高的长寿湖水库为研究对象，应用碳、氮稳定同位素技术对两个水库鱼类δ13C值、δ15N值和营养级进行比较分析.结果显示：长寿湖水库鱼类δ13C平均值（-22.66‰±1.94‰）与三峡水库（-22.59‰±1.87‰）较为接近，但长寿湖鱼类的δ15N值（13.95‰ ±3.02‰）显著高于三峡水库鱼类的δ15N值（11.98‰ ±2.25‰）.根据δ15N值计算不同食性鱼类间的营养级，三峡水库营养级为肉食性鱼类 > 杂食性鱼类 > 浮游生物食性鱼类 > 草食性鱼类；而长寿湖中则表现为浮游生物食性鱼类 > 肉食性鱼类 > 杂食性鱼类 > 草食性鱼类，营养级出现了异常现象.这一结果表明，对于人为影响（如人工喂食鱼饲料等）较大的水体，采用δ15N值计算不同食性鱼类间的营养级存在不确定性. 相似文献
7.
温泉流体地球化学方法是研究活动断裂带深浅部流体耦合变化的有利手段。通过对2011年6月至2018年7月岷江断裂带内的7个采样点进行了7次系统的调查,测定了16个气体样品中的3He/4He和δ13CCO2以及27个水样中的常量元素、微量元素和稳定同位素（δD、δ18O）,得出以下结论：①岷江断裂带温泉水化学类型主要分为Ca-HCO3、Mg-HCO3、Ca·Mg-HCO3、Mg·Ca-HCO3四种;②δD、δ18O的测量结果表明岷江断裂带温泉水主要为大气降水的补给,补给高程为3.4～4.5km;③温泉水中SiO2含量为2.49～5.92mg/L,热储温度为26.00～52.22℃,循环深度为1.17～2.67km;④Na-K-Mg三角图表明岷江断裂带温泉水均为未成熟水;⑤岷江断裂带温泉水中除B、Sr、Ba外,微量元素的富集因子均小于1,说明微量元素含量较低,主要来自于岷江断裂带的灰岩;⑥幔源和壳源之间的混合作用为控制He-C系统和He-Sr系统的主要因素,且研究结果表明3He/4He变化范围为0.02 Ra～0.68Ra（Ra为大气中3He/4He的比值,为1.39×10-6）,温泉水逸出气体中幔源He贡献率变化范围为0.07%～7.8%,表明温泉气体中的He主要来自壳源,岷江断裂带内温泉水逸出气中的CO2主要来自地壳中的灰岩（75.00%～99.47%）。2017年发生了九寨沟MS7.0地震,研究发现地震前后温泉水地球化学特征有明显变化,但幔源He较低,表明无明显幔源He增加。因此,根据岷江断裂带温泉流体地球化学数据以及相关研究资料,建立了岷江断裂带深浅部流体耦合模型,对于今后判定岷江断裂带未来中强地震的短临前兆流体异常具有一定的参考意义。 相似文献
8.
内蒙古高原岱海接受远程深循环地下水补给的环境同位素及水化学证据 总被引：2，自引：2，他引：0
利用环境同位素及水化学分析方法研究发现,岱海除了接受降水的直接补给之外,还接受泉水的补给.岱海周边泉水与井水的δD、δ18O值比当地降水明显贫化,泉水、井水显然不是来自于当地降水的补给;通过对岱海周边包气带土壤水中的氢氧稳定同位素分析发现,土壤水中的δD、δ18O值比当地降水值贫化,在地表埋深1 m附近,土壤中的盐分发生了累积,土壤水中的含盐量明显超过了土壤受蒸发所引起的增加量.研究表明岱海周边地区的大气降水不能入渗补给到潜水中,补给岱海的泉水不是来自于当地降水,而是具有同位素贫化特征的外源水.由此推断,在地层中可能存在一种地下水深循环的跨流域补给方式.在内蒙古高原地区,深循环地下水是维系湖泊不可或缺的补给源. 相似文献
9.
湖、库水体是重要的N2O排放源，在全球氮素循环及全球气候变化中具有重要作用.本文综述了目前有关湖、库水体N2O排放研究进展，重点介绍湖、库水体N2O产生和排放的过程、不同时空尺度的排放特征、N2O排放的影响因子框架及监测方法.湖、库水体N2O不仅源于内部微生物硝化作用、反硝化作用、硝化-反硝化耦合作用、脱氮作用以及极少数底栖无脊椎动物代谢过程，同时流域上游河流汇入、地表径流输入、污水排放以及地下水排泄等构成湖、库水体N2O的重要外源，但目前对内源/外源的相对贡献的定量化研究不足；湖、库水体N2O排放方式包括扩散、植物传输及少量气泡排放，对水库而言，大坝下游水电涡轮机形成的脱气作用可能是N2O排放的潜在途径.对文献综合分析表明，湖、库水体N2O排放通常呈现明显的季节变化（夏季>冬季）和日变化，同时在全球（一般低纬度>高纬度）、区域及水体内部等不同尺度上表现出显著的空间变异性；这种时空变异特征主要受到湖、库自身理化因子（温度、营养盐、溶解氧、C/N、水文）、生物因子（水生植物、藻华）以及陆域人类活动（污水排放、农业活动以及城市化等）的影响；湖、库N2O排放不同监测方法的差异也是潜在的影响因素，传统的漂浮箱法和薄边界层法均可能低估水体N2O排放通量，未来需将传统的监测方法与新型的涡度相关法相结合，减小监测方法的不确定性.结合当前湖、库水体N2O排放的研究不足，建议未来可以从湖、库N2O产生的微生物机制，区域尺度上人类活动与湖、库群N2O排放的耦合关系，水陆交错带的产、排过程，变化环境下的湖、库N2O排放以及监测方法等方面深入研究. 相似文献
10.
以安徽淮南采煤沉陷积水为研究对象,通过样品采集与测试,研究不同沉陷年限及类型积水水文地球化学和氢氧稳定同位素组成特征及影响因素.结果表明：（1）研究区水化学类型主要为Cl-Na、HCO3·Cl-Na型,沉陷积水中常量离子主要来源于蒸发岩溶解和硅酸盐风化,受蒸发作用和人为活动的影响明显,水化学组成随沉陷时间和类型变化不大.（2）淮南大气降水线方程为：δD=8.85δ18O+18.73,沉陷区积水氢氧稳定同位素值在淮南大气降水线右下方依次分布并接近降水线,表明沉陷积水主要来源于大气降水.（3）在降水稀释、水体蒸发及地下水补给的作用下,随着沉陷年限的增加,积水中重同位素越来越贫化,同一年限不同类型的积水同位素值变化较小. 相似文献
11.
In this paper, the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport, such as precipitation depth, discharge, and human activities are studied. To investigate the changes in sediment yield in this watershed, a trend analysis on sediment concentration, precipitation depth, and discharge is conducted. Precipitation depths at 2 Climate Stations （CSs）, as well as discharge and sediment transport at 3 Gauging Stations （GSs） are used to assess the features of sediment transport in the Kuye River. The rtmoff modulus （defined as the annual average discharge per unit area, L/（s·km^2）） and the sediment transport modulus （defined as the annual suspended sediment transport per unit area, t/（yr km^2）） are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m^3/s in August with an average monthly sediment concentration of 88.9 kg/m^3. However, the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m^3 and occurs in July, which has an average discharge of 42.6 m^3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August, the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In July, the average monthly median grain size of suspended load approaches another peak and decreases until September. Then, the median grain size of suspended load starts to increase until February of the following year. However, the average monthly median grain size of suspended load in the Yellow River at Toudaoguai and Longmen GSs is the smallest between early summer and late fall The median grain size in the Yellow River starts to increase in November and approaches the largest size in January. 相似文献
12.
13.
3He/4He ratios up to 3.5 times the ratio of atmospheric He were found in groundwater samples. The3He enrichment can be attributed to radiogenic3He produced by in-situ beta-decay of3H. This shows that tritiogenic3He is accumulating in confined waters. From tritiogenic3He and3H concentrations, ages of groundwaters can be calculated. Detection of tritiogenic3He gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the3H counting method. 相似文献
14.
The aim of this study is to estimate likely changes in flood indices under a future climate and to assess the uncertainty in these estimates for selected catchments in Poland. Precipitation and temperature time series from climate simulations from the EURO-CORDEX initiative for the periods 1971–2000, 2021–2050 and 2071–2100 following the RCP4.5 and RCP8.5 emission scenarios have been used to produce hydrological simulations based on the HBV hydrological model. As the climate model outputs for Poland are highly biased, post processing in the form of bias correction was first performed so that the climate time series could be applied in hydrological simulations at a catchment-scale. The results indicate that bias correction significantly improves flow simulations and estimated flood indices based on comparisons with simulations from observed climate data for the control period. The estimated changes in the mean annual flood and in flood quantiles under a future climate indicate a large spread in the estimates both within and between the catchments. An ANOVA analysis was used to assess the relative contributions of the 2 emission scenarios, the 7 climate models and the 4 bias correction methods to the total spread in the projected changes in extreme river flow indices for each catchment. The analysis indicates that the differences between climate models generally make the largest contribution to the spread in the ensemble of the three factors considered. The results for bias corrected data show small differences between the four bias correction methods considered, and, in contrast with the results for uncorrected simulations, project increases in flood indices for most catchments under a future climate. 相似文献
15.
Observations of trace gases (SO2, NH3, NO2 and O3) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH3 was found in the range of background values. Also, the average concentrations of NO2 and O3 at the different environments were in the order of background values. However, the concentrations of SO2 were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO2, NH3 and NO2 showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world. 相似文献
16.
Changes in thermal extremes of the climate of Poland in 1951–2010 are examined. Warm extremes have become more frequent, while cold extremes have become less frequent. In the warming climate of Poland, the increase in the number of extremely warm days in a year and the decrease in the number of extremely cold days in a year have been observed. Also the increase of the maximum number of consecutive hot days in a year and the decrease of the maximum number of consecutive very cold and extremely cold days in a year have been observed. However, the trends are not of ubiquitous statistic significance, as the natural variability is strong. 相似文献
17.
Cu concentrations in surface (river and lake) and subsurface waters are determined. The geographic pattern of Cu distribution in natural water is identified. This pattern is controlled by the difference between its concentrations in drained rocks and soils and the geochemical redox conditions of its migration. Territories with low, medium, and elevated Cu concentrations in natural waters are identified. The concentrations of Cu in natural waters of the region are found to be generally lower than the Clarke values. 相似文献
18.
M. MONIRUL QADER MIRZA 《水文科学杂志》2013,58(5):613-631
Abstract The basin area of the Ganges River in Bangladesh is extremely dependent on a regular water supply from upstream to meet requirements for agriculture, fisheries, navigation, salinity control, and domestic and industrial sectors. In 1975, India commissioned a barrage on the Ganges River at Farakka to divert a significant portion of the dry season flow in order to make the Calcutta Port navigable. Statistical analyses of discharge and water level data have been carried out to determine if significant changes have occurred in the hydrology of the Ganges system in Bangladesh in the post-Farakka period. Siltation of the Gorai River (an offtake of the Ganges River) has also been examined using the stage-discharge relationship and regression analysis. The analyses show that the diversion has caused considerable hydrological changes in the Ganges system in Bangladesh. The water supply in the dry season has been reduced substantially, while siltation of the Gorai River has increased significantly. 相似文献
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Ingvar B. Fridleifsson 《Pure and Applied Geophysics》1978,117(1-2):242-252
In an active spreading area like Iceland, where the regional geothermal gradient is in the range 50–150°C/km, it is normally not a problem to find high enough temperature with deep drilling, but the difficulties arise with finding permeable layers at depth within the strata. Various volcanological methods can be applied in the search for aquifers and geothermal reservoir rocks. The flow pattern (as deduced from deuterium studies) indicates that the thermal water flows preferentially along high porosity stratiform horizons and dyke swarms from the recharge areas in the highlands to the hot spring areas in the lowlands. The primary porosity of the volcanic strata is dependent on the chemical composition and the mode of eruption of the volcanic units. Both the reservoir rocks and the flow channels forming the geothermal plumbing system are thought to vary from the Tertiary to the Quaternary provinces due to environmental conditions at the eruptive sites. 相似文献