South China Karst Aquifer Storm‐Scale Hydrochemistry

Liu, Zaihua; Groves, Chris; Yuan, Daoxian; Meiman, Joe

doi:10.1111/j.1745-6584.2004.tb02617.x

Cited by 46 publications

(36 citation statements)

References 14 publications

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“…soil CO 2 concentration increases can improve carbonate chemical dissolution, thus increasing the HCO 3 -concentration. Changes are also affected by air temperature and rainfall events [35]. Our results indicate that karst processes are very sensitive to environmental change, and vary simultaneously with various climatic change (rainfall, air temperature), biological processes (soil CO 2 rise result from decomposition of organic matter) which means no remarkable time lag [6].…”

Section: Resultsmentioning

confidence: 74%

Carbonate rock dissolution rates in different landuses and their carbon sink effect

Cheng

2011

Chin. Sci. Bull.

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Research on karst processes is important for the determination of their carbon sink potential, as is research into terrestrial ecosystems in karst areas. Solutional denudation rates of soils from three karst spring watersheds supporting different land uses were studied. Solution rates showed a distinct pattern based on land use, with a generally higher rate being recorded in forest use soil.The mean values for tablet dissolution from the cultivated land, shrublands, secondary forest, grassland and primary forest were 4.02, 7.0, 40.0, 20.0, 63.5 t km -2 a -1 respectively. Changes in vegetation patterns could improve the size of karst carbon sinks; for example, in this study the carbon sink was 3 times higher in primary forest than in secondary forest soil and 9 times higher than under shrubland, equating to an increase from 5.71-7.02 to 24.86-26.17 t km -2 a -1 from cultivated land or shrub to secondary forest and to primary forest, respectively. In early research studies into karst processes, the estimation of carbonate rock dissolution rate was mainly performed using empirical equations. For example, Pulina [1,2] calculated potential dissolution rates in karsts in Poland, Europe, the temperate and subtropical regions of Asia, and in other regions. Thereafter, a worldwide correlation program for carbonate dissolution rates was undertaken by the International Union of Speleology under the framework of the limestone standard tablet method. The program involved taking 101 dissolution rate data sets from different soil depths at 25 correlation sites (USA, England, Italy, France, Australia and former Yugoslavia)(with different climate conditions) around the world; these were collected and analyzed by Gams [3]. The data from other karst areas (such as southwest China) showed that the higher the precipitation in a given study area, the higher the dissolution rate [4]. Accordingly, before the 1990s, scientific research related to email: chzhang@karst.ac.cn karst carbon sinks was mainly focused on simple karst processes and their influencing factors; much research involved analysis of just a single factor such as air temperature or precipitation.Since the 1990s, research became more integrated with an emphasis on the associated impacts of climate, hydrology and geology on karst processes. It also was introduced into the field of global change research during the implementation of IGCP 379 "Karst processes and the carbon cycle (1995-1999)", and was aimed at the estimation of the carbon sink intensity at regional (such as China [5]) and global scales. A global correlation of the carbon cycle in epikarst dynamics systems was also performed, and it was estimated that the carbon sink from global karst processes was (1.1-6.08)10 8 t C/a [6-9], or about 5.5%-30.4% of the "missing carbon sink". Moreover, the carbon sink for atmospheric CO 2 from epikarst processes in different karst regions of the world has also been investigated

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Section: Resultsmentioning

confidence: 74%

Carbonate rock dissolution rates in different landuses and their carbon sink effect

Cheng

2011

Chin. Sci. Bull.

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“…Other relevant publications include a general conceptualisation of the karst dynamics system and its role within the global carbon cycle (Yuan 1997); a holistic appreciation of the karst ecosystem (Yuan 2001); new insights into the relationship between the hydrological and geological environment and human health in China (Yuan 2002); and joint publications with American colleagues about karst aquifer storm-scale hydrochemistry (Liu et al 2004). …”

Section: International Hydrogeological Ecological and Climate Changementioning

confidence: 99%

Yuan Daoxian: ein Interview mit einem bedeutenden Hydrogeologen aus China

Goldscheider

Baker

2008

Hydrogeol J

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“…In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007. However, during low intensity rainfall and dispersed infiltration, the effect of flushing CO 2 -rich soils can dominate over dilution and the CO 2 level increases in springs (Liu et al, 2007;Vesper and White, 2004) or in diffuse flow fractured media (Liu et al, 2004). For example in a karst springs in Kentucky/Tennessee (Vesper and White, 2004), dissolved CO 2 concentrations increased after the maximum discharge was reached during storm flow, which was explained by diffuse infiltration through CO 2 -rich soils lagging behind quickflow from a sinkhole.…”

Section: Introductionmentioning

confidence: 99%

“…In these studies CO 2 concentration typically varied between 2% and 5 vol.% CO 2 . Other studies focussed on dissolved CO 2 concentrations in karst (Liu et al, 2004;Vesper and White, 2004) and epikarst (Liu et al, 2007) springs. In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Other studies focussed on dissolved CO 2 concentrations in karst (Liu et al, 2004;Vesper and White, 2004) and epikarst (Liu et al, 2007) springs. In case of concentrated infiltration via sinkholes, CO 2 concentrations can decrease during heavy rainfall due to a dilution effect (Liu et al, 2004(Liu et al, , 2007. However, during low intensity rainfall and dispersed infiltration, the effect of flushing CO 2 -rich soils can dominate over dilution and the CO 2 level increases in springs (Liu et al, 2007;Vesper and White, 2004) or in diffuse flow fractured media (Liu et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

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Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

Savoy¹,

Surbeck²,

Hunkeler³

2011

Journal of Hydrology

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Keywords:Karst hydrogeology Soil Epikarst Radon Carbon dioxide Unsaturated zone s u m m a r y This study investigated the use of radon ( 222 Rn), a radioactive isotope with a half-life of 3.8 days, and CO 2 as natural tracers to evaluate the recharge dynamics of karst aquifer under varying hydrological conditions. Dissolved 222 Rn and carbon dioxide (CO 2 ) were measured continuously in an underground stream of the Milandre test site, Switzerland. Estimated soil water 222 Rn activities were higher than baseflow 222 Rn activities, indicating elevated 222 Rn production in the soil zone compared to limestone, consistent with a 226 Ra enrichment in the soil zone compared to limestone. During small flood events, 222 Rn activities did not vary while an immediate increase of the CO 2 concentration was observed. During medium and large flood events, an immediate CO 2 increase and a delayed 222 Rn activity increase to up to 4.9 Bq/L and 11 Bq/L, respectively occurred. The detection of elevated 222 Rn activities during medium and large flood events indicate that soil water participates to the flood event. A soil origin of the 222 Rn is consistent with its delayed increase compared to discharge reflecting the travel time of 222 Rn from the soil to the saturated zone of the system via the epikarst. A three-component mixing model suggested that soil water may contribute 4-6% of the discharge during medium flood events and 25-43% during large flood events. For small flood events, the water must have resided at least 25 days below the soil zone to explain the background 222 Rn activities, taking into account the half-life of 222 Rn (3.8 days). In contrast to 222 Rn, the CO 2 increase occurred simultaneously with the discharge increase. This observation as well as the CO 2 increase during small flood events, suggests that the elevated CO 2 level is not due to the arrival of soil water as for 222 Rn. A possible explanation for the CO 2 trend is that baseflow water in the stream has lower CO 2 levels due to gas loss compared to water stored in low permeability zones. During flood event, the stored water is more rapidly mobilised than during baseflow with less time for gas loss. The study demonstrates that 222 Rn and CO 2 provides value information on the dynamics of groundwater recharge of karst aquifer, which can be of high interest when evaluating the vulnerability of such systems to contamination.

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South China Karst Aquifer Storm‐Scale Hydrochemistry

Cited by 46 publications

References 14 publications

Carbonate rock dissolution rates in different landuses and their carbon sink effect

Carbonate rock dissolution rates in different landuses and their carbon sink effect

Yuan Daoxian: ein Interview mit einem bedeutenden Hydrogeologen aus China

Radon and CO2 as natural tracers to investigate the recharge dynamics of karst aquifers

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