title: Anthropogenically enhanced chemical weathering and carbon evasion in the Yangtze Basin.
abstract: Chemical weathering is a fundamental geochemical process regulating the atmosphere-land-ocean fluxes and earth's climate. It is under natural conditions driven primarily by weak carbonic acid that originates from atmosphere CO2 or soil respiration. Chemical weathering is therefore assumed as positively coupled with its CO2 consumption in contemporary geochemistry. Strong acids (i.e. sulfuric- and nitric acid) from anthropogenic sources have been found to influence the weathering rate and CO2 consumption, but their integrated effects remain absent in the world largest river basins. By interpreting the water chemistry and overall proton budget in the Yangtze Basin, we found that anthropogenic acidification had enhanced the chemical weathering by 40% during the past three decades, leading to an increase of 30% in solute discharged to the ocean. Moreover, substitution of carbonic acid by strong acids increased inorganic carbon evasion, offsetting 30% of the CO2 consumption by carbonic weathering. Our assessments show that anthropogenic loadings of sulfuric and nitrogen compounds accelerate chemical weathering but lower its CO2 sequestration. These findings have significant relevance to improving our contemporary global biogeochemical budgets.
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jingheng
authors.initials: J
authors.lastname: Guo
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200433, China.
authors.forename: Fushun
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Chemistry, University of Oslo, 0315 Oslo, Norway.
authors.forename: Rolf David
authors.initials: RD
authors.lastname: Vogt
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yuhang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 55002, China.
authors.forename: Cong-Qiang
authors.initials: CQ
authors.lastname: Liu