Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China Soil CO2 and dilution effects

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	Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China Soil CO2 and dilution effects
	Liu, ZH (Liu, Zaihua); Li, Q (Li, Qiang); Sun, HL (Sun, Hailong); Wang, JL (Wang, Jinliang)
刊名	JOURNAL OF HYDROLOGY
	2007
卷号	337 期号:1-2 页码:207-223
关键词	hydrochemical variations different time scales epikarst springs soil CO2 effect dilution effect Southwest China
ISSN号	0022-1694
英文摘要	Two-year continuous pH, conductivity, temperature and water stage of the two typical epikarst springs, Nongla spring and Maolan spring (about 200 km apart) in subtropical karst areas of SW China were presented. Our primary study objective was to understand how karst systems respond hydrochemically to recharge at different time scales, and what the biogeochemical processes and controlling factors in the SW China epikarst environment are. A thermodynamic model was used to link the continuous data to monthly water quality data allowing the calculation of CO2 partial pressures and calcite/dolomite saturation levels on a continuous basis. Marked seasonal, diurnal and storm-scale variations were observed for pH, conductivity, CO2 partial pressures and calcite/dolomite saturation indexes of the springs, indicating that both springs are dynamic and variable systems. However, the coefficients of variation of these hydrogeochemical features tends to be in the order of seasonal >= storm-scale > diurnal. The seasonal and diurnal variations of these features (higher conductivity and lower pH in summer and at daytime; lower conductivity and higher pH in winter and at nighttime) tend to co-vary with temperature which influences the production Of CO2 in soils, thus being the driving force for the variations (soil CO2 effect). The storm-scale fluctuations occur during the spring-summer rainy days due to the storm-events. Depending on the rainfall intensities, however, there are differences in magnitudes and direction of the variations of these features. At very high rainfall intensity, the dilution effect dominates the variations, characterized by the decrease in both conductivity and calcite/dolomite saturation of the springs, while soil CO2 effect determines the variations at tower rainfall intensity, characterized by increase in CO2 partial pressure and conductivity but decrease in pH and calcite/dolomite saturation. In a word, the hydrodynamic aspects together with hydrobiogeochemical characteristics need to be taken into account to correctly explain the hydrochemical variations of the epikarst springs. Results from the study demonstrate the need to redesign hydrogeochemical sampling strategies for epikarst springs in karst areas with monsoon climate like SW China (i.e., with remarkable seasonal matching fluctuations in temperature, rainfall and vegetation). (c) 2007 Elsevier B.V. All rights reserved.
学科主题	地貌学与土壤学
WOS关键词	CARBON-DIOXIDE ; DEPOSITING STREAM ; SIERRA-NEVADA ; TEMPERATURE ; RIVER ; CHEMISTRY ; EVOLUTION ; KENTUCKY ; MOISTURE ; FOREST
WOS研究方向	Engineering ; Geology ; Water Resources
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000246028700016
内容类型	期刊论文
源URL	[http://119.78.100.197/handle/2HKVOGP0/38358]
专题	中国地质调查局
作者单位	Minist Land & Resources, Karst Dynam Lab, Guilin 541004, Peoples R China SW Univ China, Sch Resources & Environm Sci, Chongqing 400715, Peoples R China Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 55002, Peoples R China
推荐引用方式 GB/T 7714	Liu, ZH ,Li, Q ,Sun, HL ,et al. Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China Soil CO2 and dilution effects[J]. JOURNAL OF HYDROLOGY,2007,337(1-2):207-223.
APA	Liu, ZH ,Li, Q ,Sun, HL ,&Wang, JL .(2007).Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China Soil CO2 and dilution effects.JOURNAL OF HYDROLOGY,337(1-2),207-223.
MLA	Liu, ZH ,et al."Seasonal, diurnal and storm-scale hydrochemical variations of typical epikarst springs in subtropical karst areas of SW China Soil CO2 and dilution effects".JOURNAL OF HYDROLOGY 337.1-2(2007):207-223.