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Identifying the Sources of Solutes in karst Groundwater in Chongqing,China:a Combined Sulfate and Strontium Isotope Approach

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Acta Geologica Sinica(English Edition) 2012年第4期86卷 980-992页

作者： PU Junbing YUAN Daoxian ZHANG Cheng ZHAO Heping karst dynamics laboratory Institute of Karst GeologyChinese Academy of Geological Sciences International Research Center on karst under the Auspices of UNESCO

Groundwater from karst subterranean streams is among the world＇s most important sources of drinking water supplies, and the hydrochemical characteristics of karst water are impacted by both natural environment and people. Therefore, the study of hydrochemistry and its solutes＇ sources is very important to ensure the normal function of life support systems. In this paper, thirty-five representative karst groundwater samples were collected from different aquifers （limestone and dolomite） and various land use types in Chongqing to trace the sources of solutes and relative hydrochemical processes. Hydrogeochemical types of karst groundwater in Chongqing were mainly of the Ca-HCO3 type or Ca （Mg）-HCO3 type. However, some hydrochemical types of karst groundwater were the K＋Na＋Ca-SO4 type （G25 site） or Ca-HCO3＋SO4 type （G26 and G14 site）, indicating that the hydrochemistry of these sites might be strongly influenced by anthropogenic activities or unique geological characteristics. The dissolved Sr concentrations of the studied groundwater ranged from 0.57 to 15.06 ~tmmol/L, and the STSr/S6Sr varied from 0.70751 to 0.71627. The j34S-SO42- fell into a range of-6.8%o-21.5%o, with a mean value of 5.6%o. The variations of both 87Sr/S6Sr and Sr values of the groundwater samples indicated that the Sr element was controlled by the weathering of limestone, dolomite and silicate rock. However, the figure of STSr/S6Sr vs. Sr2＋/[K＋＋Na＋] showed that the anthropogenic inputs also obviously contributed to the Sr contents. For tracing the detailed anthropogenic effects, we traced the sources of solutes collected karst groundwater samples in Chongqing according to the j34S value of potential sulfate sources. The variations of both j34S and 1/ SO42- values of the groundwater samples indicated that the atmospheric acid deposition （AAD）, dissolution of gypsum （GD）, oxidation of sulfide mineral （OS） or anthropogenic inputs （SF： sewage or fertilizer） have contributed to solutes in karst groundw

关键词： sulfate isotope strontium isotope hydrogeochemistry karst groundwater Chongqing Municipality

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Attenuation of arsenic in a karst subterranean stream and correlation with geochemical factors: A case study at Lihu,South China

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Journal of Environmental Sciences 2014年第11期26卷 2222-2230页

作者： Liankai Zhang Hui Yang Jiansheng Tang Xiaoqun Qin Au Yik Yu Institute of karst Geology Chinese Academy of Geological Sciences karst dynamics laboratory Ministry of Land and Resources and Guangxi Zhuang Autonomous Region

Arsenic （As） pollutants generated by human activities in karst areas flow into subterranean streams and contaminate groundwater easily because of the unique hydrogeological characteristics of karst areas. To elucidate the reaction mechanisms of arsenic in karst subterranean streams, physical-chemical analysis was conducted by an inductively coupled plasma mass spectrometer and an X-ray fluorescence spectrometer. The results show that inorganic species account for most of the total arsenic, whereas organic arsenic is not detected or occurs in infinitesimal amounts. As（III） accounts for 51.0% ± 9.9% of the total inorganic arsenic. Arsenic attenuation occurs and the attenuation rates of total As, As（III） and As（V） in the Lihu subterranean stream are 51%, 36% and 59%, respectively. To fully explain the main geochemical factors influencing arsenic attenuation, SPSS 13.0 and CANOCO 4.5 bundled with CanoDraw for Windows were used for simple statistical analysis and redundancy analysis （RDA）. Eight main factors, i.e., sediment iron （SFe）, sediment aluminum （SAI）, sediment calcium （SCa）, sediment organic matter （SOM）, sediment manganese （SMn）, water calcium （WCa^2＋）, water magnesium （WMg^2＋）, and water bicarbonate ion （WILCOX） were extracted from thirteen indicators. Their impacts on arsenic content rank as： SFe〉SCa〉WCa^2＋〉SAl〉wHCO3^-〉SMn〉SOM〉WMg^2＋. Of these factors, SFe, SAl, SCa, SOM, SMn, WMg^2＋ and WCa＆2＋ promote arsenic attenuation, whereas WHCO3^- inhibits it. Further investigation revealed that the redox potential （Eh） and pH are adverse to arsenic removal. The dramatic distinction between karst and non-karst terrain is that calcium and bicarbonate are the primary factors influencing arsenic migration in karst areas due to the high calcium concentration and alkalinity of karst water.

关键词： karst subterranean stream Sediment Arsenic Geochemical factors Redundancy analysis

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Contribution of Oxygenic Photosynthesis to Palaeo-Oceanic Organic Carbon Sink Fluxes in Early Cambrian Upper Yangtze Shallow Sea: Evidence from Black Shale Record

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Journal of Earth Science 2016年第2期27卷 211-224页

作者： Kunyu Wu Tingshan Zhang Yang Yang Yuchuan Sun Daoxian Yuan State key laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University School of Geographical Sciences Southwest University karst dynamics laboratory MLR and GZAR Institute of Karst GeologyCAGS

The extensive transgression that occurred on the Yangtze Plate in Early Cambrian led to a massive organic carbon pool in the Niutitang Formation. A black shale core section from 3 251.08 to 3 436.08 m beneath the Earth＇s surface was studied to estimate the contribution of oxygenic photosynthesis to organic carbon sink fluxes in Early Cambrian Upper Yangtze shallow sea. Results indicate that the oxygenic photosynthesis played the most important role in carbon fixation in Early Cambrian. Organic carbon sink was mainly contributed by photosynthetic microorganisms, e.g., cyanobacteria, algae and archaea. The Niutitang Formation was formed in a deep anoxic marine shelf sedimentary environment at a sedimentation rate of ~0.09±0.03 mm/yr. The initial TOC abundance in Niutitang shale ranged from 0.18% to 7.09%, with an average of 2.15%. In accordance with the sedimentation rate and initial TOC abundance, organic carbon sink fluxes were calculated and found to range from 0.21 to 8.10×10~3 kg/km^2·yr^（-1）, especially the organic carbon sink fluxes in depth between 3 385 and 3 470 m range from 3.80 to 8.10×10~3 kg/km^2·yr^（-1）, with an average of ~6.03×10~3 kg/km^2·yr^（-1）, which is much higher than that of contemporary marine sediments. The organic carbon sink fluxes of Niutitang shale are equal to 0.56 to 21.61×10~3 kg/km^2·yr^（-1） net oxygen emitted into the Early Cambrian ocean and atmosphere, this emitted oxygen may have significantly promoted the oxygen level of the Earth＇s surface and diversification of metazoans.

关键词： oxygenic photosynthesis organic carbon sink black shale Early Cambrian UpperYangtze shallow sea.

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The features of soil erosion and soil leakage in karst peak-cluster areas of Southwest China

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Journal of Groundwater Science and Engineering 2018年第1期6卷 18-30页

作者： LUO Wei-qun JIANG Zhong-cheng YANG Qi-yong LI Yan-qing LIANG Jian-hong Institute of karst Geology CAGS key laboratory of karst Ecosystem and Rocky Desertification Ministry of Land Resources key laboratory of karst dynamics Ministry of Land Resources of Guangxi

Through utilizing water flow monitoring, rock scratching, soil wood piles and radionuclide ^(137)Cs tracing in the Longhe karst ecological experimental site(hereinafter referred to"Longhe site"), Pingguo County, Guangxi Province, the features and values of soil erosion and soil leakage in different geomorphologic locations and land uses in the karst peak-cluster depressions are showed clearly. There are four kinds of geomorphologic locations in the karst peak-cluster depression, namely peaks, strip, slopes and depression. The soil leakage modulus in the peaks and strips respectively occupy 92.43% and 96.24% of the total mean soil erosion modulus at experimental sites. On the slope, soil leakage accounted for about 75%. At the bottom of depression, surface water was the main factor of soil erosion, and at last most soil leaked into underground rivers from sinkholes. The total soil erosion modulus and the contribution rates of relative surface soil erosion in regard of peaks, slopes and depressions gradually increased. There are also five major types of land use in the karst peak-cluster depressions, farmland, Kudingcha tea plantations, young Lignum Sappan fields, shrub-grassland and pastures. The soil erosion modulus of slope farmland has the highest value with an increasing trend year by year. But soil erosion modulus of other four land use types decreased by year, which shows the "grain for green" will result in better soil protection. By handling with rocky desertification and ecological rehabilitation in Longhe site, the mean soil erosion modulus of the karst peak-cluster depression has decreased about 80% from 2003 to 2015.

关键词： Soil erosion Soil leakage karst peak-cluster depression Land use 137Cs tracing Longhe karst ecological experimental site

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Comparing the performances of WRF QPF and PERSIANN-CCS QPEs in karst flood simulation and forecasting by coupling the karst-Liuxihe model

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Frontiers of Earth Science 2022年第2期16卷 381-400页

作者： Ji LI Daoxian YUAN Yuchuan SUN Jianhong LI Chongqing Jinfo Mountain karst Ecosystem National Observation and Research Station School of Geographical SciencesSouthwest UniversityChongqing 400715China key laboratory of karst dynamics(MNR&Guangxi)Institute of karst Geology CAGSGuilin 541004China

Long-term rainfall data are crucial for flood simulations and forecasting in karst ***,in karst areas,there is often a lack of suitable precipitation data available to build distributed hydrological models to forecast karst *** precipitation forecasts(QPFs)and estimates(QPEs)could provide rational methods to acquire the available precipitation data for karst ***,coupling a physically based hydrological model with QPFs and QPEs could greatly enhance the performance and extend the lead time of flood forecasting in karst *** study served two main *** purpose was to compare the performance of the Weather Research and Forecasting(WRF)QPFs with that of the Precipitation Estimations through Remotely Sensed Information based on the Artificial Neural Network-Cloud Classification System(PERSIANN-CCS)QPEs in rainfall forecasting in karst river *** other purpose was to test the feasibility and effective application of karst flood simulation and forecasting by coupling the WRF and PERSIANN models with the karst-Liuxihe *** rainfall forecasting results showed that the precipitation distributions of the 2 weather models were very similar to the observed rainfall ***,the precipitation amounts forecasted by WRF QPF were larger than those measured by the rain gauges,while the quantities forecasted by the PERSIANN-CCS QPEs were smaller.A postprocessing algorithm was proposed in this paper to correct the rainfall estimates produced by the two weather *** flood simulations achieved based on the postprocessed WRF QPF and PERSIANN-CCS QPEs coupled with the karst-Liuxihe model were much improved over previous *** particular,coupling the postprocessed WRF QPF with the karst-Liuxihe model could greatly extend the lead time of flood forecasting,and a maximum lead time of 96 h is adequate for flood warnings and emergency responses,which is extremely important in flood simulations and forecasting.

关键词： WRF QPF PERSIANN-CCS QPEs the karst-Liuxihe model flood simulation and forecasting karst river basin

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Pollution pattern of underground river in karst area of the Southwest China

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Journal of Groundwater Science and Engineering 2018年第2期6卷 71-83页

作者： ZHOU Chang-song ZOU Sheng-zhang ZHU Dan-ni XIE Hao CHEN Hong-feng WANG Jia karst dynamics laboratory MLR Key Laboratory of Karst Ecosystem and Treatment of Rocky DesertificationInstitute of Karst Geology Chinese Academy of Geological Sciences China University of Geosciences (Beijing)

Investigation of groundwater pollution has been carried out on multiple typical karst underground river systems in recent years in order to reveal the characteristics and mechanism of underground river pollution. Through the summary of the survey results, five characteristics of underground river pollution have been revealed, including directionality, weak hysteresis, easier for reversibility, linear and intermittent(or seasonal); combining with karst geomorphic types, pollution sources(primordial, secondary pollution and compound), pollution ways and pollution receptors, three basic pollution patterns of the underground river were depicted: Recharge area pollution, runoff area pollution and discharge area pollution. At the same time, the study discloses the reality of the underground river pollution is the three basic patterns and their subgenera in combination with super imposition on the space and time. And from the angle of the hydrogeological model, the study expounds the process of underground river pollution. Finally, the study gives naming rules of pollution pattern of the underground river and sets up PISAB method of pattern recognition. The results provide scientific basis for pollution repair and management of underground river in the southwest karst region.

关键词： Underground river Pollution pattern karst region Conceptual model Characteristic

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On the karst Ecosystem

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Acta Geologica Sinica(English Edition) 2001年第3期75卷 336-338页

作者： Yuan Daoxian karst dynamics laboratory Ministry of Land and Resources Guilin 541004GuangxiChina

In this paper the author gives a definition of the karst ecosystem and discusses the characteristics of the karst environment and karst ecosystem and the relationship between life and the karst environment. Finally he... 详细信息

关键词： karst ecosystem carbonate rock karst environment

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Exploring the spatiotemporal heterogeneity of vegetation changes in subtropical humid karst region under CO2 fertilization

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Journal of Geographical Sciences 2025年第1期 65-87页

作者： CHEN Meng ZHOU Qiuwen PENG Dawei YAN Weihong School of Geography and Environmental Science Guizhou Normal University Huanjiang Observation and Research Station for karst Ecosystem Guangxi Key Laboratory of Karst Ecological Processes and Services Institute of Subtropical Agriculture CAS University of Chinese Academy of Sciences Faculty of Geographical Science Beijing Normal University Forestry Bureau of Shibing County

Terrestrial ecosystems heavily depend on vegetation,which responds to carbon dioxide （CO2） fertilization in hot and humid *** subtropical humid karst region is a hot and humid region;whether and to what extent CO2fertilization affects vegetation changes in such regions remains *** this study,we investigated the degree to which CO2fertilization influences vegetation changes,along with their spatial and temporal differences,in the subtropical humid karst region using time-lag effect analysis,a random forest model,and multiple regression *** showed that CO2fertilization plays an important role in vegetation changes,exhibiting clear spatial variations across different geomorphological zones,with its degree of influence ranging mainly between 11%and 25%.The highest contribution of CO2fertilization was observed in the karst basin and non-karstic region,whereas the lowest contribution was found in the karst plateau *** studies have primarily attributed vegetation changes in subtropical humid karst region to ecological engineering,leading to an overestimation of its contribution to these *** findings of this study enhance the understanding of the mechanism of vegetation changes in humid karst region and provide theoretical and practical insights for ecological and environmental protection in these regions.

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A new capacitive borehole tiltmeter for crustal deformation measurement and its performance analysis

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International Journal of Mining Science and Technology 2015年第2期25卷 285-290页

作者： Wu Liheng Li Tao Chen Zheng Li Hong Institute of Crustal dynamics CEA key laboratory of Crustal dynamics

Borehole inclinometers are important observation instruments used to measure ground tilt movement and monitor crustal deformation of solid tides and geological landslide *** are widely used in oil exploration,mineral resource drilling,well logging,exploration and other *** is potential for development of rock stress strain monitoring *** types of tiltmeters have been installed,such as SQ-7,FSQ,VS and ***,these tiltmeters are generally installed in a deep cave to avoid the interference of temperature,humidity,and human *** the urbanization of human society,suitable installation locations are difficult to *** solve the problem,a two-component borehole tiltmeter,named the CBT-type tiltmeter,is proposed in this *** can be installed in a borehole less than500 m deep to eliminate environmental *** tiltmeter is composed of two sophisticated gravitational swing and two capacitive *** preliminary theory and experiment analysis,its linear correlation coefficient is higher than 0.99,its co-seismic response is rapid and its noise level is up to 10 4arc seconds in practice.

关键词： Tiltmeter Solid tide Crustal deformation High precision

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Bicarbonate Daily Variations in a karst River:the Carbon Sink Effect of Subaquatic Vegetation Photosynthesis

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Acta Geologica Sinica(English Edition) 2012年第4期86卷 973-979页

作者： ZHANG Cheng WANG Jinliang PU Junbing YAN Jun Institute of karst Geology Chinese Academy of Geological Sciences karst dynamics laboratory Ministry of Land and Resources International Research Center on karst Under the Auspices of UNESCO Department of Geography and Geology Western Kentucky University

Using the Guancun River, an underground stream-fed river, in Rong＇an County of Guangxi, China as a case study, the daily biochemical cycle was examined in this paper based on the data collected a weeklong via high resolution data logger monitoring and high-frequency sampling. Furthermore, the loss of inorganic carbon along its flow path was estimated. Results show that chemical components of the groundwater input are quite stable, showing little change extent; while all of the chemical parameters from two downstream monitoring stations show diel variation over the monitoring period, suggesting that plant activity in the river has a strong influence on water chemistry of the river. The comparison of the input fluxes from the groundwater with the output fluxes of HCO~ estimated at the downstream monitoring station during the high-frequency sampling period shows a strong decrease of HCO~, indicating that the river is losing inorganic carbon along its flow path. The loss is estimated to be about 1,152 mmol/day/m of HCO~ which represent about 94.9 kg/day of inorganic carbon along the 1,350 m section of the Guancun River. It means that HCO~ entering the river from karst underground stream was either consumed by plants or trapped in the authigenic calcite and thus constitutes a natural sink of carbon for the Guancun karst system.

关键词： Diel cycle carbon isotope photosynthetic process subaquatic vegetation karst river carbon sink

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