International Research Center on Karst

Guilin, China

International Research Center on Karst

Guilin, China
Time filter
Source Type

Wang P.,Chinese Academy of Geological Sciences | Wang P.,International Research Center on Karst | Wang P.,China University of Geosciences | Hu G.,Chinese Academy of Geological Sciences | And 4 more authors.
Aquatic Botany | Year: 2017

The stable carbon isotopic composition of submerged plants (δ13C P ) can be controlled by physiological and environmental factors. Herein, we took advantage of a short, natural karst river with an annual mean bicarbonate (HCO3 -) value of 3.8mmolL-1 to study the stable carbon isotopic composition of submerged plants along the river and the influence of environmental conditions on the δ13C P values. The δ13C P values of Ottelia auminata, Potamogeton wrightii, Vallisneria natans, and Hydrilla verticillata from upstream to downstream show a gradient distribution and ranged from -34.78‰ to -27.83‰, -36.56‰ to -23.70‰, -35.06‰ to -25.29‰, and -38.56‰ to -26.32‰, respectively and even more depleted values for the first two species at the uppermost site. Diurnal variation of water chemistry and concentration of the dissolved inorganic carbon (DIC) and the stable carbon isotopic composition of DIC (δ13C D ) indicate that the river has a very high net photosynthetic rate. The gradient distribution of δ13C P values was consistent with CO2 being a declining source of inorganic carbon for photosynthesis in the downstream transect. The results demonstrate that the high DIC concentration with lower negative δ13C value, particularly in karst water environment has a significant role in controlling the stable carbon isotopic composition of submerged plants living in it. © 2017 Elsevier B.V.

Kang Z.,Karst Dynamics Laboratory | Kang Z.,International Research Center on Karst | He S.,Karst Dynamics Laboratory | He S.,International Research Center on Karst | Luo Y.,Guangxi Geology Survey
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2015

Limestone and dolomite are common carbonate rocks. Because of their different karstification mechanism, the different landscape would be formed. In Southwest of China, dolomite locates on the different classes of karst basis level of erosion, while the pure limestone locates at upper the mountain. So, the epikarst zone has a duality structure because of the special strata combination. Based on the mornitoring to discharge and hydrochemistry of Landiantang epikarst spring, Nongla, Guangxi, it is found that the hydrochemical type of most water samples is HCO3-Ca·Mg. The variation trend of the Ca2+ and Mg2+ is not very clear in seasonal timescale. But it is more sensitive to short-term precipitation dilution and CO2 effect of forest vegetation. “Equivaleng dissolution line”(EDL) is defined by the relationship between concentration of Ca2+ and Mg2+. In this paper, EDL can be used to distinguish the causes of the differences of spring hydrochemistry under different precipitation conditions. In addition, based on the analysis on nearly ten years data of the hydrochemistry and discharge data of Landiantang epikarst spring, it is shown that spring discharge and major ions concentration in karst water are all increased under the situation of vegetation restoration. All of above is further evidence of the vegetation effect in karst process. ©, 2015, Jilin University Press. All right reserved.

He S.-Y.,Chinese Academy of Geological Sciences | He S.-Y.,International Research Center on Karst | Kang Z.-Q.,Chinese Academy of Geological Sciences | Kang Z.-Q.,International Research Center on Karst | And 6 more authors.
Advances in Climate Change Research | Year: 2012

The karst process acts as carbon sequestration for atmospheric CO2. The amount of karst carbon sequestration (KCS) depends on the discharge of karst catchment and inorganic carbon concentration of the water body. Based on the data from the monitoring station on Banzhai subterranean stream located in Maolan National Nature Reserve of Guizhou province, the process and influence factors of KCS have been analyzed. It shows that the amount of KCS is about 353 t C per year in the catchment of Banzhai subterranean stream, and there is good linear relationship between the strength of KCS and discharge of the stream at various time scales. Therefore, how to monitor the discharge accurately is the key to the estimation of KCS. And stations with real-time monitoring function are very important for KCS calculation because of strong seasonal variability of the karst water cycle.

Kang Z.Q.,Guangxi General Institute of Geological Exploration | Kang Z.Q.,Chinese Academy of Geological Sciences | Kang Z.Q.,International Research Center on Karst | He S.Y.,Chinese Academy of Geological Sciences | He S.Y.,International Research Center on Karst
Advanced Materials Research | Year: 2013

It was proved that karst processing during groundwater cycle is one of carbon sinks to the atmosphere CO2. To understand the carbon transfer path among the three phases of air, carbonate rocks and karst groundwater in epigenic karst system is very important for mechanic studies of karst carbon sink. There are 8 carbon stable isotope sample sites, including 5 groundwater sites and 3 gaseous CO2 sites in Banzhai river catchment. The total 41 samples, including 38 karst water samples and 3 CO2 samples are acquired in a whole hydrological year of 2010. 4 couples CO2 partial pressure including free air and soil air are tested in site. Based on analysis the carbon stable isotope and CO2 partial pressure data above, it is found that the mostly carbon in free air and karst water is from soil air. The carbon transfer path in epigenic karst system can be divided into 4 steps: 1. the photosynthesis of vegetation take CO2 from free air; 2. the respiration of plant roots and decomposition of humic substance release CO2 to soil layer; 3. the gaseous CO2 is transfer to liquid HCO3 - negion by karst process during the water cycle; 4. the bicarbonate in groundwater move to river or ocean fellow the groundwater flow. The forest and soil takes a "booster pump" action increasing the CO2 partial pressure from free air to soil and it is very important in karst process. © (2013) Trans Tech Publications, Switzerland.

Kang Z.-Q.,Guangxi Geological Survey | Kang Z.-Q.,Institute of Karst Geology | Kang Z.-Q.,International Research Center on Karst | Liang L.-G.,Guangxi Geological Survey | And 4 more authors.
Acta Geoscientica Sinica | Year: 2014

Based on years' automatic monitoring of dynamic hydrological state of an epikarst spring in Nongla, Guangxi, the authors found that, under the good vegetation coverage, the discharge mode is different in different seasons. It is mainly the runoff discharge by spring in the wet season and consumption of ecological water requirement in the dry season. In 2012, the precipitation from April to August accounted for 66.24% of the whole year. At the same time, the discharge of spring accounted for 90.89% and the karst carbon sink accounted for 90.46% of the whole year. It is evident that the karst carbon sink occurs mainly in the wet season because of the higher runoff coefficient. In the study area, carbon sink is controlled by rainwater dilution, CO2 effect and water-rock interaction (WRI). At the beginning of precipitation, the concentration of HCO3 - is continuously reduced, controlled by rain dilution. However, it is also obviously affected by CO2 effect and WRI. HCO3 - concentration fluctuation with time. At the later stage of spring discharge, WRI is dominant again and HCO3 - concentration tends to be somewhat stable. From the monitoring data obtained in the past decade, the concentrations of Ca2+, Mg2+ and HCO3 - in the karst dynamic system were significantly increased with the recovery of the secondary forest vegetation. With the concentration of HCO3 - as an example, the average value was 356.55 mg/L during the period of 2003-2005, whereas it was 432.97 m/L in 2012, the difference being 76.42 mg/L, and the value was increased by 21.4% during the ten years.

Cao J.,Chinese Academy of Geological Sciences | Cao J.,International Research Center on Karst | Yuan D.,Chinese Academy of Geological Sciences | Yuan D.,International Research Center on Karst | And 8 more authors.
Acta Geologica Sinica | Year: 2012

Carbonate rock outcrops cover 9%-16% of the continental area and are the principal source of the dissolved inorganic carbon (DIC) transferred by rivers to the oceans, a consequence their dissolution. Current estimations suggest that the flux falls between 0.1-0.6 PgC/a. Taking the intermediate value (0.3 PgC/a), it is equal to 18% of current estimates of the terrestrial vegetation net carbon sink and 38% of the soil carbon sink. In China, the carbon flux from carbonate rock dissolution is estimated to be 0.016 PgC/a, which accounts for 21%, 87.5%-150% and 2.3 times of the forest, shrub and grassland net carbon sinks respectively, as well as 23%-40% of the soil carbon sink flux. Carbonate dissolution is sensitive to environmental and climatic changes, the rate being closely correlated with precipitation, temperature, also with soil and vegetation cover. HCO 3 - in the water is affected by hydrophyte photosynthesis, resulting in part of the HCO 3 - being converted into DOC and POC, which may enhance the potential of carbon sequestration by carbonate rock dissolution. The possible turnover time of this carbon is roughly equal to that of the sea water cycle (2000a). The uptake of atmospheric/soil CO 2 by carbonate rock dissolution thus plays an important role in the global carbon cycle, being one of the most important sinks. A major research need is to better evaluate the net effect of this sink in comparison to an oceanic source from carbonate mineral precipitation.

Zhu T.,Chinese Academy of Geological Sciences | Zhu T.,International Research Center on Karst | Zhu T.,Chinese Academy of Sciences | Zeng S.,Nanjing Agricultural University | And 12 more authors.
Soil Biology and Biochemistry | Year: 2016

A 15N-tracing study was conducted to investigate the gross N transformation rates involved in the production and consumption of NH4 + and NO3 - in karst region soils (a calcareous and a red soil) from southwest China under woodland. The gross mineralization rate of organic N to NH4 + was much lower in calcareous soil (3.71 mg N kg-1 d-1) than in red soil (5.57 mg N kg-1 d-1), while the total gross nitrification rate was significantly higher in calcareous soil (5.80 mg N kg-1 d-1) than in red soil (0.70 mg N kg-1 d-1). Microbial NO3 - immobilization accounted for 2.9% and 153% of the total nitrification in calcareous soil and red soils respectively. Thus the calcareous soils in the karst region have a low biological N retention capacity and high N losses, which are further aggravated by the high precipitation and fractured soil structure. © 2016 Elsevier Ltd.

Kang Z.-Q.,Wuhan University | Kang Z.-Q.,Chinese Academy of Geological Sciences | Kang Z.-Q.,International Research Center on Karst | Yuan D.-X.,Wuhan University | And 14 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2011

The karst process is important composition of global carbon cycle because it can take-up CO2 from atmosphere. To calculate karst carbon sequestration (Kcs) is useful to complete the theory of global carbon cycle. By the karst dynamic system theory, the Kcs is controlled by groundwater discharge and HCO3 - mass concentration. The Banzhai River catchment, located in Maolan National Nature Reserve of Guizhou, was chosen as the study area. By the auto-monitoring technique, the discharge and water chemistry data of Banzhai River catchment were obtained. Based on the analysis of relationship between discharge, HCO3 - concentration and karst carbon sequestration under different precipitation conditions including storm period, no/weak precipitation period and dry season. Kcs has positive correlation with discharge and negative correlation with HCO3 - concentration. It shows that the discharge of catchment is main factor of Kcs rather than HCO3 - concentration. The larger discharge of karst catchment, the larger Kcs from atmosphere.

Huang F.,Chinese Academy of Geological Sciences | Huang F.,International Research Center on Karst | Zhang C.,Chinese Academy of Geological Sciences | Zhang C.,International Research Center on Karst | And 7 more authors.
Environmental Earth Sciences | Year: 2015

New findings have shown that the contribution of carbonate weathering to the atmospheric CO2 sink is far greater than previous estimates, through the combined action of carbonate dissolution, the global water cycle, and photosynthetic uptake of dissolved inorganic carbon (DIC). However, in order for calculations to be accurate, any carbon source effect should be deducted from the overall carbon sink. In this study, we carried out high temporal resolution monitoring of flow and hydrochemistry within the Xiaolongbei (XLB) silicate catchment and Beidiping (BDP) carbonate catchment for 1 year. We found the dissolved inorganic carbon concentrations to be higher in BDP than in XLB, and the annual inorganic carbon fluxes in BDP are roughly 23.8 times higher than those in XLB. Similarly, the rate of carbonate rock dissolution is much higher than the rate of silicate rock dissolution. We find carbonate rock dissolution to respond rapidly to rainfall events, and it is sensitive to rainfall changes on hourly, diurnal, and seasonal scales. The high rate of carbonate rock dissolution gives rise to the high concentrations of DIC, Ca, Mg, and to the high inorganic carbon flux in this basin. Differences between the theoretical and calculated contributions of atmospheric and soil CO2 to the DIC are possibly due to CO2 outgassing. © 2015, Springer-Verlag Berlin Heidelberg.

Kang Z.Q.,Hubei University | Kang Z.Q.,Key Laboratory of Karst Dynamics | Kang Z.Q.,International Research Center on Karst | Yu F.F.,Hubei University | And 9 more authors.
Water-Rock Interaction - Proceedings of the 13th International Conference on Water-Rock Interaction, WRI-13 | Year: 2010

The hydrogeological condition of an interfluve area, located in the town of Mengxu, Guangxi, China, is discriminated by using the trace element strontium. The Ca/Sr ratio can be used as an indicator of the karst groundwater runoff conditions. In this case, 3 strong flow zones could be distinguished by the Ca/Sr ratio value of 400. For verification purposes, 9 boreholes and 2 geophysical exploration sections were carried out. The boreholes and geophysical data support the hydrogeochemical results. © 2010 Taylor & Francis Group, London.

Loading International Research Center on Karst collaborators
Loading International Research Center on Karst collaborators