Hydrologically-driven variations in the karst-related carbon sink fluxes: Insights from high-resolution monitoring of three karst catchments in Southwest China

Zou, Cheng; Liu, Zaihua; Zhao, Min; Yang, Rui

doi:10.1016/j.jhydrol.2015.11.049

Cited by 56 publications

(27 citation statements)

References 34 publications

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“…Soil CO 2 is a key driving force of karst processes and related carbon sequestration (Yang et al, 2012;Zeng et al, 2016), because the soil CO 2 concentration is about 10 to 100 times higher than that in the atmosphere (Drever, 1994). Also, the CO 2 partial pressure (pCO 2 ) in groundwater is mainly determined by the soil pCO 2 .…”

Section: Soil Pco 2 Calculationmentioning

confidence: 99%

“…However, recent investigations have found evidence that contemporary climate change is accelerating the chemical weathering rate and altering the relevant carbon fluxes (Raymond and Cole, 2003;Macpherson et al, 2008;Raymond et al, 2008;Gislason et al, 2009). Duo to the high sensitivity of carbonate weathering to environmental change (Liu et al, 2007;Yang et al, 2012), the response of this carbon sink may be rapid and considerable (Liu and Dreybrodt, 2015;Zeng et al, 2016). For instance, Raymond et al (2008) and Raymond and Cole (2003) attributed a proximately 20% increase of alkalinity (HCO 3 -+CO 3 2-) (increasing from 20.3 mg/l to 25.4 mg/l) in the Mississippi River during the past half-century to a 9% increase in precipitation.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of climate impacts on the karst-related carbon sink in SW China using MPD and GIS

Zeng

Jiang

Liu

2016

Global and Planetary Change

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Riverine carbon fluxes of some catchments in the world have significantly changed due to contemporary climate change and human activities. As a large region with an extensive karstic area of nearly 7.5 × 10 5 km 2 , Southwest (SW) China has experienced dramatic climate changes during recent decades. Although some studies have investigated the karst-related carbon sink in some parts of this region, the importance of climate impacts have not been assessed. This research examined the impacts of recent climate change on the karst-related carbon sink in the SW China for the period 1970-2013, using a modified maximal potential dissolution (MPD) method and GIS. We first analyzed the major determinants of carbonate dissolution at a spatial scale, calculated the total karst-related carbon sink (TCS) and carbon sink fluxes (CSFs) in the SW China karst region with different types of carbonate rocks, and then compared with other methods, and analyzed the causes of CSFs variations under the changed climate conditions. The results show that the TCS in SW China experienced a dramatic change with regional climate, and there was a trend with TCS decreasing by about 19% from 1970s to 2010s. This decrease occurred mostly in Guizhou and Yunnan provinces, which experienced larger decreases in runoff depth in the past 40 years (190 mm and 90 mm, respectively) due to increased air temperature (0.33 ℃ and 1.04 ℃ , respectively) and decreased precipitation (156 mm and 106 mm, respectively). The mean value of CSFs in SW China, calculated by the modified MPD method, was approximately 9.36 t C km-2 a-1. In addition, there were large differences in CSFs among the provinces, attributed to differences in regional climate and to carbonate lithologies. These spatiotemporal changes depended mainly on hydrological variations (i.e., discharge or runoff depth). This work, thus, suggests that the karst-related carbon sink could respond to future climate change quickly, and needs to be considered in the modern global carbon cycle model.

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Section: Soil Pco 2 Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessment of climate impacts on the karst-related carbon sink in SW China using MPD and GIS

Zeng

Jiang

Liu

2016

Global and Planetary Change

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“…In karst water, mainly dominated by calcium and bicarbonate ions, there is a known relationship in estimating bicarbonate and electrical conductivity. The estimation of bicarbonate concentration from electrical conductivity is already applied in some studies (Liu et al, 2007;Lambàn et al, 2015;Zeng et al, 2016). The relationship among these parameters is described by Groves and Meiman (2005) and Krawczyk and Ford (2006).…”

Section: Estimations Of Field Valuesmentioning

confidence: 99%

SIc–Abacus: An in–situ tool for estimating SIc and Pco2 in the context of carbonate karst

Peyraube

Lastennet

Denis

et al. 2019

Journal of Hydrology

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This article aims to provide an on the spot, handy field tool that can be used in estimating the Saturation Index with respect to calcite in karst aquifers in a limestone context. It relies on an abacus that gives the SIc by using measured pH and bicarbonate concentration as coordinates. The analytical expressions of the carbonate equilibrium equations are derived in order to calculate SIc from values that can be measured on field. Using these established relationships, we propose an Abacus built from the SIc=f(Pco 2 eq) reference frame, hence called SIc-Abacus. Accuracy of SIc calculation is also discussed. SIc is calculated with values measured considering uncertainty coming from pH (±0.05 pH units), temperature (±0.1 °C), bicarbonate and calcium concentrations (±2.5 mg/L and ±2 mg/L). This gives, for each sample, a range of possible SIc values of ±0.060 pH units (for a bicarbonate concentration close to 300 mg/L). The effect on SIc range of possible values given by bicarbonate and calcium uncertainties is about 10 times lower than the effect brought by pH uncertainty. Also, bicarbonate and calcium concentration can be estimated from electrical conductivity leading to a possible range of SIc value of ±0.087 pH units. In both cases, the range of possible values of SIc varies according to the bicarbonate concentration. Using Cussac and Lascaux sites, an evaluation was done. Results show the goodness of fit (R 2 =0.96) between the calculated SIc from measured pH, bicarbonate and calcium concentration and the estimated SIc values generated from the SIc-Abacus. Apart from calculating SIc, another method which is an alternative use of the generated SIc equation focused on obtaining pH using parameters such as electrical conductivity and dissolved CO 2 measurements is presented. The study shows that SIc-Abacus can be a new in-situ tool for karst aquifer surveys. It can facilitate in making a swift decision that tackles carbonate karst issues (e.g. when selecting sites or in deciding if extensive monitoring should be performed or not based from a specific objective).

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“…This study was conducted in a subtropical primary forest (26 • 14 48 N, 105 • 45 51 E; elevation, 1460 m), located in the karst CZ of southwestern China. This region has a typical subtropical monsoon climate, with a mean annual precipitation of 1255 mm, and mean annual air temperature of 15.1 • C (Zeng et al, 2016). The soils are characterized by a high ratio of exposed rock, shallow and nonhomogeneous soil cover, and complex underground drainage networks, e.g., grooves, channels, and depressions (Chen et al, 2010;Zhang et al, 2011;Wen et al, 2016).…”

Section: Site Informationmentioning

confidence: 99%

The strategies of water–carbon regulation of plants in a subtropical primary forest on karst soils in China

et al. 2018

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Coexisting plant species in a karst ecosystem may use diverse strategies of trade off between carbon gain and water loss to adopt to the low soil nutrient and low water availability conditions. An understanding of the impact of CO 2 diffusion and maximum carboxylase activity of Rubisco (V cmax ) on the light-saturated net photosynthesis (A) and intrinsic water use efficiency (iWUE) can provide insight into physiological strategies of the water-carbon regulation of coexisting plant species used in adaptation to karst environments at the leaf scale. We selected 63 dominant species (across 6 life forms) in a subtropical karst primary forest in southwestern China, measured their CO 2 response curves, and calculated the corresponding stomatal conductance to CO 2 (g s ), mesophyll conductance to CO 2 (g m ), and V cmax . The results showed that g s and g m varied about 7.6-and 34.5fold, respectively, and that g s was positively related to g m . The contribution of g m to the leaf CO 2 gradient was similar to that of g s . g s / A, g m / A and g t / A was negatively related to V cmax / A. The relative limitations of g s (l s ), g m (l m ), and V cmax (l b ) to A for the whole group (combined six life forms) were significantly different from each other (P < 0.05). l m was the largest (0.38 ± 0.12), followed by l b (0.34 ± 0.14), and l s (0.28 ± 0.07). No significant difference was found between l s , l m , and l b for trees and tree/shrubs, while l m was the largest, followed by l b and l s for shrubs, grasses, vines and ferns (P < 0.05). iWUE varied about 3-fold (from 29.52 to 88.92 µmol CO 2 mol −1 H 2 O) across all species, and was significantly correlated with g s , V cmax , g m / g s , and V cmax / g s . These results indicated that karst plants maintained relatively high A and low iWUE through the covariation of g s , g m , and V cmax as an adaptation to a karst environment.

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Hydrologically-driven variations in the karst-related carbon sink fluxes: Insights from high-resolution monitoring of three karst catchments in Southwest China

Cited by 56 publications

References 34 publications

Assessment of climate impacts on the karst-related carbon sink in SW China using MPD and GIS

Assessment of climate impacts on the karst-related carbon sink in SW China using MPD and GIS

SIc–Abacus: An in–situ tool for estimating SIc and Pco2 in the context of carbonate karst

The strategies of water–carbon regulation of plants in a subtropical primary forest on karst soils in China

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