title: Estimation of nutrient discharge from the Yangtze River to the East China Sea and the identification of nutrient sources.
abstract: Based on a time-series dataset and the mass balance method, the contributions of various sources to the nutrient discharges from the Yangtze River to the East China Sea are identified. The results indicate that the nutrient concentrations vary considerably among different sections of the Yangtze River. Non-point sources are an important source of nutrients to the Yangtze River, contributing about 36% and 63% of the nitrogen and phosphorus discharged into the East China Sea, respectively. Nutrient inputs from non-point sources vary among the sections of the Yangtze River, and the contributions of non-point sources increase from upstream to downstream. Considering the rice growing patterns in the Yangtze River Basin, the synchrony of rice tillering and the wet seasons might be an important cause of the high nutrient discharge from the non-point sources. Based on our calculations, a reduction of 0.99Tg per year in total nitrogen discharges from the Yangtze River would be needed to limit the occurrences of harmful algal blooms in the East China Sea to 15 times per year. The extensive construction of sewage treatment plants in urban areas may have only a limited effect on reducing the occurrences of harmful algal blooms in the future.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China; College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China; Chinese Academy for Environmental Planning, Beijing, 100012, China.
authors.forename: Yindong
authors.initials: Y
authors.lastname: Tong
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
authors.forename: Xiaoge
authors.initials: X
authors.lastname: Bu
authors.affiliation: Yang Ming Institute, Ningbo University, Ningbo, 315122, China.
authors.forename: Junyue
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
authors.forename: Maodian
authors.initials: M
authors.lastname: Liu
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Tan
authors.affiliation: School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
authors.affiliation: School of Environment and Natural Resources, Renmin University of China, Beijing, 100872, China. Electronic address: zhw326@ruc.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, 810008, China.
authors.forename: Zhaorong
authors.initials: Z
authors.lastname: Mi
authors.affiliation: Chinese Academy for Environmental Planning, Beijing, 100012, China. Electronic address: malekuan@126.com.
authors.forename: Lekuan
authors.initials: L
authors.lastname: Ma
authors.affiliation: College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Haian Environmental Protection Bureau, Jiangsu, 226600, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ni
mesh_terms: D002681:China; D016208:Databases, Factual; D004784:Environmental Monitoring / Q000379:methods*; D005068:Eutrophication; D005502:Food; D057097:Harmful Algal Bloom; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D045483:Rivers; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014876:Water Pollution / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D010758:Phosphorus; D009584:Nitrogen
keywords: Harmful algal blooms; Non-point sources; Nutrient discharges; Yangtze river; Yangtze river estuary