Chemical weathering and CO2 consumption in the Xijiang River basin, South China |
| |
| Authors: | Quanzhou Gao Zhen Tao Xiakun Huang Ling Nan Kefu Yu Zhengang Wang |
| |
| Institution: | aSchool of Geography and Planning, Sun Yat-sen University, Guangzhou 510275, PR China;bKey Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China;cHohai University, Nanjing 210098, and Wuzhou Branch, Guangxi Regional Hydrological and Water Resources Bureau, Wuzhou 543002, PR China;dShenzhen Geotechnical Investigation & Surveying Co., Ltd., Shenzhen 518028, PR China |
| |
| Abstract: | Monthly samples of riverine water were collected and analyzed for the concentrations of major ions (Ca2+, Mg2+, K+, Na+, HCO3−, SO42−, Cl−, NO3−), dissolved silicon, and total dissolved solids (TDS) at Wuzhou hydrological station located between the middle and lower reaches of the Xijiang River (XJR) from March 2005 to April 2006. More frequent sampling and analysis were carried out during the catastrophic flooding in June 2005. Stoichiometric analysis was applied for tracing sources of major ions and estimating CO2 consumption from the chemical weathering of rocks. The results demonstrate that the chemical weathering of carbonate and silicate rocks within the drainage basin is the main source of the dissolved chemical substances in the XJR. Some 81.20% of the riverine cations originated from the chemical weathering processes induced by carbonic acid, 11.32% by sulfuric acid, and the other 7.48% from the dissolution of gypsum and precipitates of sea salts within the drainage basin. The CO2 flux consumed by the rock chemical weathering within the XJR basin is 2.37 × 1011 mol y− 1, of which 0.64 × 1011 mol y− 1 results from silicate rock chemical weathering, and 1.73 × 1011 mol y− 1 results from carbonate rock chemical weathering. The CO2 consumption comprises 0.38 × 1011 mol during the 9-d catastrophic flooding. The CO2 consumption from rock chemical weathering in humid subtropical zones regulates atmospheric CO2 level and constitutes a significant part of the global carbon budget. The carbon sink potential of rock chemical weathering processes in the humid subtropical zones deserves extra attention. |
| |
| Keywords: | Chemical weathering CO2 consumption Riverine ion Catastrophic flood The Xijiang River basin |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
