[Temporal and Spatial Variations of Dissolved Inorganic Carbon and Its Stable Isotopic Composition in the Surface Stream of Karst Groundwater Recharge]

Li Li; Jun-Bing Pu; Jian-Hong Li; Tao Zhang

doi:10.13227/j.hjkx.201607171

[Temporal and Spatial Variations of Dissolved Inorganic Carbon and Its Stable Isotopic Composition in the Surface Stream of Karst Groundwater Recharge]

Huan Jing Ke Xue. 2017 Feb 8;38(2):527-534. doi: 10.13227/j.hjkx.201607171.

[Article in Chinese]

Authors

Li Li^{1

2}, Jun-Bing Pu¹, Jian-Hong Li¹, Tao Zhang^{1

2}

Affiliations

¹ Key Laboratory of Karst Dynamics, Ministry of Land and Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China.
² School of Geographical Sciences, Southwest University, Chongqing 400715, China.

PMID: 29964508
DOI: 10.13227/j.hjkx.201607171

Abstract

Stable carbon isotope of dissolved inorganic carbon (δ¹³C_DIC), which is mainly constituted by HCO₃^- in karst water, is widely used to trace the different sources and influential factors of dissolved inorganic carbon (DIC). In order to understand the distribution of DIC and δ¹³C_DIC in subtropical karst area, this paper researched the water chemistry and δ¹³C_DIC in a karst surface stream in detail, which is fed by Guancun subterranean stream in Liuzhou City, Guangxi Province, in the southwest of China. The results showed that the contents of DIC in subterranean stream outlet (G1 site) ranged from 4.60 to 4.90 mmol·L^-1 with an average of 4.73 mmol·L^-1 in dry season, and from 2.80 to 4.70 mmol·L^-1 with an average of 4.23 mmol·L^-1 in rainy season. The contents of DIC in 1.35 km downstream site (G2 site) ranged from 4.30 to 4.90 mmol·L^-1 with an average of 4.56 mmol·L^-1 in dry season, and from 3.00 to 4.70 mmol·L^-1 with an average of 4.20 mmol·L^-1 in rainy season. The δ¹³C_DIC of subterranean stream outlet (G1 site) varied from -12.8‰ to -11.53‰ with an average of -12.22‰ in dry season, and from -13.12‰ to -11.01‰ with an average of -12.28‰ in rainy season. The δ¹³C_DIC of stream downstream site (G2 site) ranged from -11.71‰ to -9.55‰ with an average of -10.73‰ in dry season, and ranged from -12.18‰ to -9.85‰ with an average of -11.10‰ in rainy season. The contents of DIC of G1 site were higher than those of G2 site. The DIC contents in dry season in both G1 and G2 site were higher than those in rainy season. The values of δ¹³C_DICof G1 and G2 site in dry season were more positive than those in rainy season. The δ¹³C_DICvalue of G1 site was more negative than that of G2 site. The main sources of DIC in underground river and surface stream were soil CO₂and carbonate dissolution. However, the differences of DIC and δ¹³C_DICbetween G1 and G2 site showed that CO₂degassing and photosynthesis of aquatic plants had significant influence on water DIC and δ¹³C_DIC value. This study is helpful to understand the dynamic change and distribution of DIC and δ¹³C_DIC in karst surface stream.

Keywords: Guangxi; carbonate dissolution; dissolved inorganic carbon (DIC); karst surface stream; δ13CDIC.

Publication types

English Abstract