The Correlation of Inorganic C,O Isotopic Values for Lake Chenghai Sediments and Its Environmental Implications     

汪福顺  万国江  刘丛强  胥思勤 《中国地球化学学报》2002,21(2):186-192

As one of the lakes on the Yunnan-Guizhou plateau, Lake Chenghai, which is a typical closed lake with the precipitation accounting for one-third or more of the annual water input, has a high total salinity (almost like a saline lake). The inorganic C, O isotopic composition of lake sediments bears much sensitive information about environmental change in the catchment, while their correlations revealed the hydrological conditions under which the lake was closed. Their compositional variations are controlled by temperature, precipitation, photosynthesis, dissolving equilibrium of the carbonate system and hydrological condition. According to our research on inorganic C, O isotopic composition of Lake Chenghai sediments, we investigated the environmental change of this catchment several decades ago. The results showed that Lake Chenghai has kept good hydrological closing conditions in the past several decades, as indicated by the good correlation of inorganic C, O isotopic composition of sediments; and that the environmental change in this catchment shows a tendency of periodical evolution on a 10⁻¹¹-years scale, although the signal noise is relatively high at the bottom of the sediment core. And we also can extend C, O isotopes, a sensitive environmental indicator, to nearly saline lake environments with a high degree of mineralization.  相似文献   

露天采煤矿区土地的复垦：土壤透水性实验   总被引：1，自引：0，他引：1  

党志  万国江 《矿物岩石地球化学通报》1996,(4)

露天采煤矿区土地的复垦：土壤透水性实验党志，万国江（中国科学院地球化学研究所，贵阳５５０００２）关键词露天采煤矿区，复垦，土壤透水性实验煤矿区土地复垦常用的方法是在矿渣表面覆盖一层约５～４０ｃｍ厚的土壤，种草植树以恢复植被。但在一些化学风化强烈的地区...  相似文献   

Mechanism of Seasonal Deterioration of Water Quality in Lake Baihua,China   总被引：3，自引：1，他引：3  

白占国  吴丰昌等 《中国地球化学学报》1996,15(2):185-188

Water quality of Lake Baihua was found worsening in the autumn of 1994.Studies have shown that the decomposition of organic matter in the upper-level sediments resulted in seasonal anoxia with the release of P,Mn,and S^2- from the sediments to the overlying water column,and the increase of NO2^- concentration led to blackening of the water column,deat of fishes and secondary Mn pollution.  相似文献   

沉积物-水界面的生物地球化学作用   总被引：18，自引：0，他引：18  

吴丰昌  万国江 《地球科学进展》1996,11(2):191-197

沉积物－水界面是天然水体在物理、化学和生物特征等方面差异性最显著和负责水体和沉积物之间物质输送和交换的重要边界环境。对沉积物－水界面生物地球化学的定义、研究方法和它在水体微量物质循环中所起的作用、物质迁移方式、典型氧化还原敏感性元素转化反应（Ｃ、Ｏ、Ｎ）、界面扩散通量和表面扩散亚层的意义和估算等进行了讨论。   相似文献   

Variability of aquatic chemistry in central Guizhou karst region, China   总被引：1，自引：1，他引：0  

白占国  万国江 《中国地球化学学报》1998,17(3):241-248

It is necessary to understand the aquatic chemical characterstics of natural surface fresh water for water quality assessment.The chemical data from different kinds of water in the central Guizhou karst area showd that spring water from carbonate rock cracks(crack-water)is of neutrality or meta-alkalinity and [C] Ca II type.The amounts of all ions and the concentrations of HCO3^- and Ca^2 were higher in the autumn than in the spring,The crack-water was influenced by the infiltration of surface water in the process of erosion and /or trans-portation with decreasing HCO3 and increasing pH,SO4^2-,Cl^-,K^ and Na^ during running in a certain distance on the land surface .In particular,the chemical compositions of the waters at Tianxingqiao(upper-stream),Shuiliandong(mid-waterfall)and Luoshuitan(down-pool)near the Huangguoshu Waterfall were much different from those of the crack-water.The concentration of SO4^2-,Na^ ,Fe^3 and NO3^- varied closely with seasons.The CaCO3 deposited violently with CO2 release in the spring ,In Lake Hongfeng the HCO3^-/SO4^2- equivalent ratios were only 2.1-2.4 ,but Ca^2 /Mg^2 up to 2.4-4.2.The Cl^- concentration increased by a factor of 1 and Na^ by order of magnitude relative to the spring water.These indicated the increase in artificial pollutant discharge in the Lake Hongfeng watershed.In addition,Proewater in the soils covering carbonate rocks belongs to strongly mineralized water,The obvious differences in water quality were controlled by carbonate deposition,sulphate mineralization and nitrogen fixation as well as ammonification.It is indicated thaty the chemical compositions in the waters from the karst region were unstable and changeable.  相似文献   

环境生态系统散落核素示踪研究新进展   总被引：13，自引：2，他引：13  

万国江  P. G. APPLEBY 《地球科学进展》2000,15(2):172-177

环境生态系统中的放射性核素既具有生态毒性,对生物和人体健康产生重要影响,又具有稳定的衰变函数和输入通量,对环境生态系统具有重要示踪价值。人类可利用放射性核素来认识环境生态系统:①环境生态系统中放射性核素的基准:放射性强度与环境生态系统之间的平衡关系;②环境生态系统中放射性核素的行为:在环境生态系统不同宿体和组分间的运移关系。考察放射性核素在生态系统不同环节中比活度的变化有助于认识环境生态过程生物地球化学作用的影响。    相似文献   

一种基于B/S分布对象模型的设计实现     

张春海  刘洁  倪国江 《中国海洋大学学报(自然科学版)》2001,31(3):430-434

随着 Internet的深入发展 ,Web应用逐渐呈现面向对象和分布的特点 ,如何在浏览器端为用户提供一个面向对象的接口 ,使用户能够透明的访问分布在不同网络结点的数据 ,成为当前研究的热点。该文提出一种基于 Browser/ Server( B/ S)的分布对象模型 ,该模型以客观世界的实体为核心 ,通过构造组件对象模型封装对象的接口 ,并采用建立在组件对象模型基础上的分布技术 ,通过任务分派 ,远程过程调用 ,存取分布在不同网络结点的对象 ,完成用户对数据库的访问请求  相似文献   

Ultraviolet absorbance titration for the determination of conditional stability constants of Hg（Ⅱ） and dissolved organic matter   总被引：1，自引：0，他引：1  

BAI Yingchen WU Fengchang WAN Guojing LIU Congqiang FU Pingqing LI Wen 《中国地球化学学报》2008,27(1):46-52

Strong interaction between natural dissolved organic matter （DOM） and Hg（Ⅱ） may influence the transport, conversion, toxicity and bio-validity of mercury in the environment. In this paper ultraviolet （UV） absorbance titration was employed for the first time for the determination of the conditional stability constants of Hg（Ⅱ） and （DOM）. With increasing Hg（Ⅱ） concentrations, the UV absorbance of fulvic acid, humic acid, and DOM in river increases progressively. By linear and non-linear model fitting, the conditional stability constants （lgK） of Hg（Ⅱ） and DOM were worked out to be 3.54-4.93 and 3.64-4.85, respectively. The results are consistent with those acquired by the typical fluorescence quenching titration method, with the maximum relative error of lgK being 2.6% and the average relative error being 0.2%. The UV absorbance titration method has the advantages of rapid determination, simple performance, and it will probably become a new approach to studying interactions between DOM and trace metallic ions.  相似文献   

我国海岛开发与保护的战略思考          下载免费PDF全文

文艳  倪国江  闫金玲 《海洋开发与管理》2016,33(Z2):13-18

我国海岛开发保护虽取得显著成效,但问题亦十分突出。海岛开发保护对我国经济社会长远发展具有重大的战略意义。文章基于可持续发展视角,借鉴国际经验,从战略层面对我国海岛开发保护的进一步发展进行研究和思考,尝试提出可行的海岛开发保护战略目标、思路和对策建议。  相似文献   

Physical mechanisms of plant roots affecting weathering and leaching of loess soil     

LI Yong    ZHANG Qingwen    WAN Guojiang  HUANG Ronggui  PIAO Hechun  BAI Lingyu & LI Lu . State Key Laboratory of Soil Erosion  Dryland Farming on the Loess Plateau  Institute of Soil  Water Conservation  Chinese Academy of Sciences  Yangling  China  . Institute of Agro-Environment  Sustainable Development  Chinese Academy of Agricultural Sciences  Beijing  China  . Institute of Geochemistry  Chinese Academy of Sciences  Guiyang  China 《中国科学D辑(英文版)》2006,49(9):1002-1008

Vegetation is an important factor in maintaining ecological balance and improving eco-environment. For improving environment, vegetation cover, as a substitute for the integrated action of stems and leaves, seems to be a crucial factor. However, recent st…  相似文献