The southeastern coastal region is one of the most developed and populated areas in China. Meanwhile, it has been severely impacted by acid rain over many years. The chemical compositions and carbon isotope compositions of dissolved inorganic carbon (delta C-13(DIC)/in river water in the high-flow season were investigated to estimate the chemical weathering and associated atmospheric CO2 consumption rates as well as the acid-deposition disturbance. Mass balance calculations indicated that the dissolved loads of major rivers in the Southeast Coastal River Basin (SECRB) were contributed to by atmospheric (14.3 %, 6.6 %-23.4 %), anthropogenic (15.7 %, 0 %-41.1 %), silicate weathering (39.5 %, 17.8 %-74.0 %) and carbonate weathering inputs (30.6 %, 3.9 %-62.0 %). The silicate and carbonate chemical weathering rates for these river watersheds were 14.2-35.8 and 1.8-52.1 t km(-2) a(-1), respectively. The associated mean CO2 consumption rate by silicate weathering for the whole SECRB was 191 x 10(3) mol km(-2) a(-1). The chemical and delta C-13(DIC) evidence indicated that sulfuric and nitric acid (mainly from acid deposition) were significantly involved in the chemical weathering of rocks. There was an overestimation of CO2 consumption at 0.19 x 10(12) g Ca-1 if sulfuric and nitric acid were ignored, which accounted for about 33.6% of the total CO2 consumption by silicate weathering in the SECRB. This study quantitatively highlights the role of acid deposition in chemical weathering, suggesting that the anthropogenic impact should be seriously considered in estimations of chemical weathering and associated CO2 consumption. Publication name | BIOGEOSCIENCES, 15 (16):4955-4971; 10.5194/bg-15-4955-2018 AUG 22 2018 | Author(s) | Liu, Wenjing; Xu, Zhifang; Sun, Huiguo; Zhao, Tong; Shi, Chao; Liu, Taoze | Corresponding author(s) | XU Zhifang zfxu@mail.iggcas.ac.cn -Chinese Acad Sci, Inst Earth Sci, Inst Geol & Geophys, Key Lab Cenozo Geol & Environm, Beijing 100029, Peoples R China -CAS Ctr Excellence Life & Paleoenvironm, Beijing 100044, Peoples R China -Univ Chinese Acad Sci, Beijing 100049, Peoples R China | Author(s) from IGCAS | LIU Taoze | View here for the details
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