不同水体在大气环境中对碳酸盐岩溶蚀过程及溶解无机碳δ<sup>13</sup>C演变规律

赵光帅; 朱义年; 谢银财; 沈利娜; 吴华英; 李腾芳; 黄奇波

doi:10.11932/karst20250109

不同水体在大气环境中对碳酸盐岩溶蚀过程及溶解无机碳δ¹³C演变规律

doi: 10.11932/karst20250109

赵光帅^{1, 2, 3, 4,},
朱义年²,
谢银财^{1, 3},
沈利娜^{1, 4},
吴华英^{1, 4, ,},
李腾芳^{1, 4},
黄奇波^{1, 4}

1.
中国地质科学院岩溶地质研究所/自然资源部、广西岩溶动力学重点实验室, 广西桂林 541004
2.
桂林理工大学环境科学与工程学院, 广西桂林 541004
3.
联合国教科文组织国际岩溶研究中心/岩溶动力系统与全球变化国际联合研究中心, 广西桂林 541004
4.
广西平果喀斯特生态系统国家野外科学观测研究站, 广西平果 531406

基金项目: 国家自然科学基金联合基金(U21A2041)；广西自然科学基金面上项目(2025GXNSFAA069711, 2025GXNSFAA069865)；中央引导地方专项(XZ202301YD0005C)；国家自然科学基金(42372294)；中国地质调查局地质调查项目(DD20230081)

详细信息

作者简介:
赵光帅（1989－），男，博士，主要从事岩溶环境地球化学与气候变化研究。E-mail：zgskarst@163.com

通讯作者:
吴华英（1983－），女，博士，研究方向：岩溶水文地质。E-mail：wuhuaying@mail.cgs.gov.cn。

中图分类号: P641.3
计量
- 文章访问数: 11
- HTML浏览量: 2
- PDF下载量: 4
- 被引次数: 0
出版历程
- 收稿日期: 2024-09-24
- 录用日期: 2025-03-06
- 修回日期: 2025-02-26
- 刊出日期: 2025-02-25

Dissolution process of carbonate rocks by different types of water in atmospheric environment and δ¹³C evolution of dissolved inorganic carbon

ZHAO Guangshuai^{1, 2, 3, 4
,},
ZHU Yinian²,
XIE Yincai^{1, 3},
SHEN Lina^{1, 4},
WU Huaying^{1, 4
, ,},
LI Tengfang^{1, 4},
HUANG Qibo^{1, 4}

1.
Institute of Karst Geology, CAGS / Key Laboratory of Karst Dynamics, MNR & GZAR, Guilin, Guangxi 541004, China
2.
College of Environmental Science and Engineering, Guilin University of Technology, Guilin, Guangxi 541004, China
3.
International Research Centre on Karst under the Auspices of UNESCO/National Center for International Research on Karst Dynamic System and Global Change, Guilin, Guangxi 541004, China
4.
Pingguo Karst Ecosystem, National Observation and Research Station, Pingguo, Guangxi 531406, China

摘要

摘要: 碳酸盐岩溶解是一种发生在地球浅表层环境下的特殊地质过程，因其地球化学过程具有低温性、开放性、敏感性和生物参与性等特点，导致岩溶水体溶解无机碳（DIC）浓度及其稳定碳同位素（δ¹³C_DIC）值的多变性。本研究开展大气开放环境中不同水体浸泡碳酸盐岩试片实验，探究大气降水、降水流经岩溶土壤及进入碳酸盐岩含水层再出露地表后对碳酸盐岩溶蚀的影响及δ¹³C_DIC的演变规律。结果表明降水及降水在土壤中渗流再出露地表后，即使无水生光合植物和土壤CO₂的持续输入，其对碳酸盐岩仍具有较强的溶蚀作用，而相同条件下岩溶管道/裂隙水出露地表后对碳酸盐岩溶蚀作用微弱或不溶蚀。在无水生光合植物和土壤CO₂持续输入的大气开放系统水体中，当${\rm{SO}}_4^{2-}$＞29 mg∙L⁻¹或${\rm{NO}}_3^{-}$＞50 mg∙L⁻¹时，${\rm{SO}}_4^{2-}$、${\rm{NO}}_3^{-}$产生的盐效应和与阳离子形成的离子对作用可显著提高方解石溶解度，促进方解石溶解。土壤渗流水和岩溶管道/裂隙水出露地表后水中CO₂在数小时内即可完成脱气作用，并使水体δ¹³C_DIC值显著增重，增幅可达+10.98‰。
- 丫吉试验场 /
- 碳酸盐岩溶解 /
- 大气开放环境 /
- 溶解无机碳δ¹³C同位素 /
- CO₂脱气
Abstract: Carbonate dissolution is a geological process that occurs in the shallow surface environment of the Earth. Due to its geochemical characteristics—such as low temperature, openness, sensitivity, and biological participation—it leads to variability in the concentration of dissolved inorganic carbon (DIC) and its δ¹³C (δ¹³C_DIC) values in karst water. In addition, although the global distribution of carbonate rocks (approximately 15.2%) is smaller than that of silicate rocks (approximately 41.8%), the rapid kinetics of carbonate weathering contributes to approximately 68% of DIC in large rivers all over the world. Therefore, exploring the effects of different types of water on the dissolution of carbonate rocks, changes in DIC concentration, and carbon isotope characteristics are of great significance. This study selects the Yaji Karst Experimental Site, a karst area in Southwest China characterized by acid rain, as the research object to conduct experimental investigations in the atmospheric environment. Additionally, this study examines the effects of atmospheric precipitation, soil water, and karst groundwater on this process. The effects of continuous soil CO₂ input and aquatic photosynthetic plants are excluded. This study also explores the influence of hydrochemical components in different types of water on the dissolution of carbonate rocks under acid rain conditions. Besides, it examines the control of CO₂ degassing and CO₂ exchange at the water–gas interface on the evolution of δ¹³C_DIC.The results indicate as follows, (1) Precipitation, along with its infiltration into the soil and subsequent exposure to the surface, still exert a significant dissolution effect on carbonate rocks, even in the absence of a continuous input of soil CO₂ and aquatic photosynthetic plants. However, under the same conditions, karst pipelines/fissure water exert weak or no dissolution effects on carbonate rocks after its exposure to the surface. (2) As the soaking time increases, the dissolution amount of carbonate rocks per unit time gradually decreases, and ultimately transforms into calcite crystals, with the highest dissolution rate of approximately 19.7 mg·(cm²·h)⁻¹. Except for the precipitation soaking group, the concentrations of DIC in the other soaking solutions gradually decrease and tend to stabilize. Furthermore, the decrease in DIC in the karst groundwater soaking solution is greater than that in the soil leaching soaking solution. The δ¹³C_DIC values increase progressively with longer soaking time, ranging from an initial value of −18.21‰ to −12.66‰, and reaching values between −5.79‰ and 3.11‰. Except for the precipitation soaking group, the CO₂ partial pressure (pCO₂) in the other soaking solutions rapidly decreases and tends to stabilize. The stable pCO₂ level in each soaking solution is mainly observed: the pCO₂ level in soil leaching soaking solution (1,000–3,000 ppmv) is higher than that in karst pipeline/fissure water soaking solution (1,000 ppmv) but is roughly comparable to that in precipitation soaking solution. The level of stable pCO₂ in all soaking solutions is higher than that of atmospheric pCO₂ (approximately 420 ppmv), with the former being roughly two to eight times higher than the latter. (3) If water is in an open atmospheric system without continuous input of soil CO₂ and without aquatic photosynthetic plants, when concentrations of SO$_4^{2-}$ exceed 29 mg∙L⁻¹ or concentrations of NO$_3^{-}$ exceed 50 mg∙L⁻¹, the salt effect and ion pair effect produced by SO$_4^{2-}$ and NO$_3^{-}$ can significantly increase the solubility of calcite and promote its dissolution. If the concentrations of SO$_4^{2-}$ and NO$_3^{-}$ in water are high, the saturation index of calcite, calculated based on Ca²⁺ and HCO$_3^{-}$ concentrations, may not accurately reflect the dissolution/crystallization state of calcite. Therefore, the simultaneous effects of various ions in water on calcite dissolution/crystallization should be considered, including ion effects, salt effects, and ion pair effects. (4) After soil vadose water or karst pipeline/fissure water is exposed to the surface, CO₂ in the water can complete the degassing process within a few hours. In the absence of a continuous input of soil CO₂ and aquatic photosynthetic plants, pCO₂ quickly reaches an equilibrium state and ceases to be the major factor controlling the dissolution/crystallization of calcite. The CO₂ degassing effect significantly increases the δ¹³C_DIC value, with an increase of up to +10.98 ‰. This results in a substantial discrepancy between the actual and theoretical contributions of soil or atmospheric CO₂ to DIC.
- Yaji experimental site /
- carbonate rock dissolution /
- open atmospheric environment /
- δ¹³C of dissolved inorganic carbon /
- CO₂ degassing

HTML

图 1 研究区位置及采样点周边环境(a-研究区位置；b-S31下降泉；c-S54表层岩溶泉；d-CF2钻孔；e-土壤采样点)

Figure 1. Location of the study area and the surrounding environment of sampling points (a:location of the study area; b:S31 spring; c:S54 epikarst spring; d:CF2 borehole; e:soil sampling point)

下载: 全尺寸图片幻灯片

图 2 动态浸泡实验装置

Figure 2. Dynamic soak experimental device

下载: 全尺寸图片幻灯片

1 动态浸泡实验

1. Dynamic soak experimental

下载: 全尺寸图片幻灯片

图 3 不同类型浸泡液中岩石试片质量差值

Figure 3. Quality differences of rock tablets in various types of soaking solutions

下载: 全尺寸图片幻灯片

图 4 不同类型浸泡液中主要水化学指标变化特征

Figure 4. Characteristics of changes in major hydrochemical indexes in various types of soaking solutions

下载: 全尺寸图片幻灯片

图 5 不同类型浸泡液中δ¹³C_DIC变化特征

Figure 5. Characteristics of changes in δ¹³C_DIC in various types of soaking solutions

下载: 全尺寸图片幻灯片

图 6 不同类型浸泡液中方解石饱和指数变化特征

Figure 6. Characteristics of changes in calcite saturation indexes in various types of soaking solutions

下载: 全尺寸图片幻灯片

图 7 不同类型浸泡液中主要水化学指标与试片质量差关系（除初始浸泡液；a-Ca²⁺与试片质量差；b-${\rm{HCO}}_3^{-}$与试片质量差；c- pCO₂与试片质量差；d-电导率与试片质量差）

Figure 7. Relationship between major hydrochemical indexes of the soaking solutions and quality difference of rock tablets. (Except for the initial soaking solution; a: Ca²⁺ vs. quality difference of rock tablets; b: ${\rm{HCO}}_3^{-}$ vs. quality difference of rock tablets; c: pCO₂ vs. quality difference of rock tablets; d: conductivity vs. quality difference of rock tablets)

下载: 全尺寸图片幻灯片

图 8 浸泡液中${\rm{SO}}_4^{2-}$、${\rm{NO}}_3^{-}$与方解石SI关系

Figure 8. Relationship between ${\rm{SO}}_4^{2-}$, ${\rm{NO}}_3^{-}$ and calcite saturation index in soaking solutions

下载: 全尺寸图片幻灯片

图 9 浸泡液中${\rm{SO}}_4^{2-}$、${\rm{NO}}_3^{-}$与试片质量差值关系

Figure 9. Relationship between ${\rm{SO}}_4^{2-}$, ${\rm{NO}}_3^{-}$ and quality difference of rock tablets in soaking solutions

下载: 全尺寸图片幻灯片

图 10 各端元对浸泡液中DIC贡献的变化趋势

Figure 10. Change trend of the contributions of various sources to DIC in soaking solutions

下载: 全尺寸图片幻灯片

表 1 桂林丫吉试验场坡面土壤主要理化指标含量

Table 1. Contents of major physicochemical indicators in the slope soil of Yaji Experimental Site

深度/cm	pH	容重/ g∙cm⁻³	含水率/%	水溶性盐总量/ mg∙kg⁻¹	阳离子交换量/ cmol∙kg⁻¹	碳酸钙/ g∙kg⁻¹	有机质/ g∙kg⁻¹	δ¹³C_有机碳/‰	δ¹³C_无机碳/‰
0~10	6.66	1.18	29.8	100	30.5	5.97	72.6	−21.36	−13.45
10~20	6.34	1.02	31.2	120	30.4	9.36	55.9	−19.24	−12.88
20~30	6.42	0.93	32.7	190	30.4	11.4	45.2	−17.03	−16.22

下载: 导出CSV

表 2 岩石试片尺寸及主要化学成分

Table 2. Sizes and major chemical components of rock tablets

试片岩性	采样点	形状	直径/mm	高度/mm	表面积/cm²	CaO	MgO	CO₂	酸不溶物
试片岩性	采样点	形状	直径/mm	高度/mm	表面积/cm²	质量分数/%
灰岩	桂林市七星岩	圆饼状	40	3	28.9	55.69	0.42	42.97	0.67

下载: 导出CSV

表 3 浸泡液水化学指标检测结果统计

Table 3. Statistics of testing results of water chemical indexes in soaking solutions

浸泡液类型		pH	Ca²⁺	Mg²⁺	K⁺	Na⁺	${\rm{HCO}}_3^{-}$	${\rm{SO}}_4^{2-}$	${\rm{NO}}_3^{-}$	Cl⁻	电导率	pCO₂	δ¹³C_DIC
浸泡液类型		pH	mg·L⁻¹								us·cm⁻¹	ppmv	‰
L10 (n=9)	最大值	8.07	51.80	17.48	6.02	2.46	149.00	36.50	76.30	6.54	407.00	7709	−3.18
	最小值	7.20	37.81	15.10	4.69	1.38	108.69	31.84	/	4.58	326.00	931	−16.64
	平均值	7.59	46.52	16.06	5.09	1.74	124.68	33.29	−	5.01	378.56	3281	−10.63
	标准差	0.30	4.39	0.87	0.50	0.38	11.89	1.55	−	0.61	25.43	2152	4.60
	变异系数	3.95	9.43	5.40	9.76	21.74	9.54	4.67	−	12.19	6.72	66	−43.28
L20 (n=9)	最大值	7.74	56.36	18.55	3.58	2.97	243.96	7.38	119.72	7.86	449.50	12749	−3.97
	最小值	6.88	50.72	17.45	3.11	2.56	134.18	6.41	/	7.23	329.00	4121	−13.35
	平均值	7.19	53.56	17.84	3.34	2.78	153.27	6.76	−	7.51	388.33	6982	−8.56
	标准差	0.30	2.16	0.39	0.13	0.13	34.58	0.35	−	0.19	33.10	2481	3.00
	变异系数	4.13	4.02	2.16	3.99	4.80	22.56	5.13	−	2.55	8.52	36	−35.11
L30 (n=9)	最大值	7.76	64.70	23.34	1.40	2.72	231.78	9.56	164.67	9.64	539.00	16749	−5.05
	最小值	7.17	52.57	21.46	0.94	1.97	105.73	7.65	0.19	8.60	421.00	3499	−18.21
	平均值	7.41	57.68	22.28	1.07	2.17	147.52	8.43	107.26	8.89	480.39	6963	−10.19
	标准差	0.21	5.05	0.57	0.14	0.23	41.28	0.55	68.79	0.31	42.66	3928	4.58
	变异系数	2.78	8.75	2.57	13.35	10.56	27.98	6.55	64.13	3.54	8.88	56	−44.94
CP (n=9)	最大值	7.98	24.43	0.14	0.13	0.47	72.90	2.13	1.76	0.83	114.00	1919	−3.11
	最小值	7.22	3.42	0.04	0.09	/	3.67	1.70	1.11	0.46	9.89	114	−12.66
	平均值	7.54	13.84	0.08	0.11	−	41.07	1.93	1.58	0.73	65.49	1092	−6.18
	标准差	0.30	8.41	0.04	0.01	−	26.00	0.15	0.26	0.12	40.16	615	3.13
	变异系数	3.93	60.77	46.95	12.90	−	63.29	8.01	16.51	16.70	61.33	56	−50.65
CS54 (n=9)	最大值	7.94	92.31	0.61	0.15	0.82	238.81	10.16	38.75	3.03	432.00	3648	−3.27
	最小值	7.55	39.31	0.41	0.03	0.04	73.48	7.04	35.87	2.65	195.00	904	−16.42
	平均值	7.80	59.62	0.46	0.10	0.45	135.38	7.91	37.98	2.87	288.67	2050	−9.13
	标准差	0.13	20.54	0.06	0.03	0.27	66.03	0.89	0.98	0.15	89.99	992	5.57
	变异系数	1.65	34.44	13.36	35.13	60.51	48.77	11.24	2.59	5.41	31.18	48	−60.99
CS31 (n=9)	最大值	7.96	89.76	0.77	0.33	0.92	238.81	10.57	30.45	2.72	412.00	5070	−3.38
	最小值	7.64	38.89	0.61	0.05	/	77.15	6.19	29.36	2.29	189.40	959	−16.11
	平均值	7.81	58.69	0.66	0.17	−	141.53	7.25	30.10	2.57	280.38	2221	−9.18
	标准差	0.10	19.95	0.06	0.09	−	63.50	1.36	0.33	0.14	85.87	1432	5.27
	变异系数	1.28	34.00	9.06	54.99	−	44.87	18.78	1.08	5.42	30.63	64	−57.37
CCF2 (n=9)	最大值	7.96	98.43	0.65	0.38	1.07	283.82	11.60	14.54	2.94	441.00	10965	−2.51
	最小值	7.38	31.74	0.40	0.21	0.14	73.48	7.52	11.01	2.57	154.10	809	−16.09
	平均值	7.75	56.90	0.46	0.30	0.54	149.75	8.63	13.88	2.78	264.88	3146	−9.05
	标准差	0.17	23.99	0.08	0.05	0.30	76.11	1.43	1.25	0.13	103.25	3230	4.96
	变异系数	2.21	42.17	17.92	18.21	55.19	50.82	16.55	9.02	4.84	38.98	103	−54.81

下载: 导出CSV

参考文献(24)

[1]	Goldscheider N, Chen Z, Auler A S, Bakalowicz M, Broda S, Drew D, Hartmann J, Jiang G, Moosdorf N, Stevanovic Z, Veni G. Global distribution of carbonate rocks and karst water resources[J]. Hydrogeology Journal, 2020, 28: 1661-1677.
[2]	Zhang S, Bai X, Zhao C, Tan Q, Luo G, Wang J, Li Q, Wu L, Chen F, Li C, Deng Y, Yang Y, Xi H. Global CO₂ consumption by silicate rock chemical weathering: Its past and future[J]. Earth's Future, 2021, 9: e2020EF001938.
[3]	Dreybrodt W, Buhmann D, Michaelis J, Usdowski E. Geochemically controlled calcite precipitation by CO₂-outgassing: Field measurements of precipitation rates in comparison to theoretical predictions[J]. Carsologica Sinica, 1992, S1: 9-24.
[4]	刘再华, Dreybrodt W. 方解石沉积速率控制的物理化学机制及其古环境重建意义[J]. 中国岩溶, 2002, 21(4):252-257. doi: 10.3969/j.issn.1001-4810.2002.04.004 LIU Zaihua, Dreybrodt W. Physicochemical mechanisms of rate-determining of calcite deposition and their implications for paleo-environmental reconstruction[J]. Carsologica Sinica, 2002, 21(4): 252-257. doi: 10.3969/j.issn.1001-4810.2002.04.004
[5]	闫志为. 硫酸根离子对方解石和白云石溶解度的影响[J]. 中国岩溶, 2008, 27(1):24-31. doi: 10.3969/j.issn.1001-4810.2008.01.005 YAN Zhiwei. Influences of ${\rm{SO}}_4^{2-}$ on the solubility of calcite and dolomite[J]. Carsologica Sinica, 2008, 27(1): 24-31. doi: 10.3969/j.issn.1001-4810.2008.01.005
[6]	Jiang Y J, Hu Y J, Schirmer M. Biogeochemical controls on daily cycling of hydrochemistry and δ¹³C of dissolved inorganic carbon in a karst spring-fed pool[J]. Journal of Hydrology, 2013, 478: 157-168. doi: 10.1016/j.jhydrol.2012.12.001
[7]	Pu J B, Li J H, Khadka M B, Martin J B, Zhang T, Yu S, Yuan D. In-stream metabolism and atmospheric carbon sequestration in a groundwater-fed karst stream[J]. Science of the Total Environment, 2017, 579: 1343-1355. doi: 10.1016/j.scitotenv.2016.11.132
[8]	Zhang T, Li J H, Pu J B, Martin J B, Khadka M B, Wu F, Li L, Jiang F, Huang S, Yuan D. River sequesters atmospheric carbon and limits the CO₂ degassing in karst area, southwest China[J]. Science of the Total Environment, 2017, 609: 92-101. doi: 10.1016/j.scitotenv.2017.07.143
[9]	Omelon C R, Pollard W H, Andersen D T. A geochemical evaluation of perennial spring activity and associated mineral precipitates at Expedition Fjord, Axel Heiberg Island, Canadian High Arctic[J]. Applied Geochemistry, 2006, 21: 1-15. doi: 10.1016/j.apgeochem.2005.08.004
[10]	周小萍, 蓝家程, 张笑微, 徐尚全. 岩溶溪流的脱气作用及碳酸钙沉积: 以重庆市南川区柏树湾泉溪流为例[J]. 沉积学报, 2013, 31(6):1014-1021. ZHOU Xiaoping, LAN Jiacheng, ZHANG Xiaowei, XU Shangquan. CO₂ outgassing and precipitation of calcium carbonate in a karst stream: A case study of Baishuwan spring in Nanchuan, Chongqing[J]. Acta Sedimentologica Sinica, 2013, 31(6): 1014-1021.
[11]	章程, 肖琼. 桂林漓江水体溶解无机碳迁移与水生光合碳固定研究[J]. 中国岩溶, 2021, 40(4):555-564. ZHANG Cheng, XIAO Qiong. Study on dissolved inorganic carbon migration and aquatic photosynthesis sequestration in Lijiang River, Guilin[J]. Carsologica Sinica, 2021, 40(4): 555-564.
[12]	袁道先, 刘再华, 林玉石, 等. 中国岩溶动力系统[M]. 北京: 地质出版社, 2002:1−275. YUAN Daoxian, LIU Zaihua, LIN Yushi, et al. Karst dynamic systems of China[M]. Beijing: Geology Press, 2002:1−275.
[13]	Li W, Yu L J, Yuan D X, Xu H B, Yang Y. Bacteria biomass and carbonic anhydrase activity in some karst areas of southwest China[J]. Journal of Asian Earth Sciences, 2004, 24: 145-152. doi: 10.1016/j.jseaes.2003.10.008
[14]	Zhang C, Yuan D X, Cao J H. Analysis of the environmental sensitivities of a typical dynamic epikarst system at the Nongla monitoring site, Guangxi, China[J]. Environmental Geology, 2005, 47: 615-619. doi: 10.1007/s00254-004-1186-x
[15]	章程, 袁道先. IGCP448: 岩溶生态系统全球对比研究进展[J]. 中国岩溶, 2005, 24(1):83-88. ZHANG Cheng, YUAN Daoxian. IGCP448: Progresses of world correlation of karst ecosystem[J]. Carsologica Sinica, 2005, 24(1): 83-88.
[16]	黄奇波, 吴华英, 程瑞瑞, 李腾芳, 罗飞, 赵光帅, 李小盼. 桂林岩溶区石灰土壤对酸雨缓冲作用的观测及其对岩溶碳汇的指示意义[J]. 地球学报, 2022, 43(4): 461−471. HUANG Qibo, WU Huaying, CHENG Ruirui, LI Tengfang, LUO Fei, ZHAO Guangshuai, LI Xiaopan. Buffering effect of lime soil on acid rain and its influence on the evaluation of the karst carbon sink effect. Acta Geoscientica Sinica, 2022, 43(4): 461−471.
[17]	赵光帅, 黄奇波, 朱义年, 李腾芳, 普政功. 石灰土对硫酸型酸雨缓冲过程模拟及碳汇效应研究[J]. 中国岩溶, 2022, 41(5):796-807. doi: 10.11932/karst20220504 ZHAO Guangshuai, HUANG Qibo, ZHU Yinian, LI Tengfang, PU Zhenggong. Simulation of buffering process and carbon sink effect of lime soil on sulfuric acid rain[J]. Carsologica Sinica, 2022, 41(5): 796-807. doi: 10.11932/karst20220504
[18]	Zhao G, Huang Q, Zhu Y, Xu Y, Pu Z. Simulation of the buffering process of karst soil on sulfuric acid rain and the characteristic of δ¹³C_DIC and the carbon sink flux in Guilin City, southwest China[J]. Environmental Earth Sciences, 2023, 82: 296. doi: 10.1007/s12665-023-10948-6
[19]	Cuntz M. Carbon cycle: a dent in carbon's gold standard[J]. Nature, 2011, 477: 547-548. doi: 10.1038/477547a
[20]	Yang H, Zhou L, Huang L, Cao J, Groves C. A comparative study of soil carbon transfer between forest soils in subtropical karst and clasolite areas and the karst carbon sink effect in Guilin, Guangxi, China[J]. Environmental Earth Sciences, 2015, 74: 921-928. doi: 10.1007/s12665-014-3903-4
[21]	闫志为, 刘辉利, 张志卫. 温度及CO₂对方解石、白云石溶解度影响特征分析[J]. 中国岩溶, 2009, 28(1):7-10. YAN Zhiwei, LIU Huili, ZHANG Zhiwei. Influences of temperature and P_CO2 on the solubility of calcite and dolomite[J]. Carsologica Sinica, 2009, 28(1): 7-10.
[22]	Shin W J, Chung G S, Lee D, Lee K S. Dissolved inorganic carbon export from carbonate and silicate catchments estimated from carbonate chemistry and δ¹³C_DIC[J]. Hydrology and Earth System Sciences, 2011, 15: 2551-2560. doi: 10.5194/hess-15-2551-2011
[23]	Palmer S M, Hope D, Billett M F, Dawson J J C, Bryant C L. Sources of organic and inorganic carbon in a headwater stream: Evidence from carbon isotope studies[J]. Biogeochemistry, 2001, 52: 321-338. doi: 10.1023/A:1006447706565
[24]	Doctor D H, Kendall C, Sebestyen S D, Shanley J B, Ohte N, Boyer E W. Carbon isotope fractionation of dissolved inorganic carbon (DIC) due to outgassing of carbon dioxide from a headwater stream[J]. Hydrological Processes, 2008, 22: 2410-2423. doi: 10.1002/hyp.6833