Human-driven spatiotemporal distribution of phosphorus flux in the environment of a mega river basin

• Published in: The Science of the total environment 2021-01, Vol.752, p.141781-141781, Article 141781
• Main Authors: Cui, Meng, Guo, Qingjun, Wei, Rongfei, Tian, Liyan
• Format: Article
• Language: English
• Subjects: Agriculture sources; Anthropogenic phosphorus; Eutrophication; Water quality; Yangtze River Basin
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.141781

Large river basins transport considerable nutrients to the ocean every year. However, phosphorus (P) generated by human activities not only threatens aquatic ecosystem health in the river basin, but also has a negative effect on the estuary water environment. To better understand the environmental effects of anthropogenic P in a mega basin, we examined its inputs and distribution characteristics, and analyzed the factors driving it in the Yangtze River Basin (YRB) and sub-catchments. Anthropogenic P flux in the sub-catchments gradually increased from upper to lower reaches, and hotspots were primarily concentrated in traditional agricultural areas such as the Sichuan Basin and the Middle-Lower Yangtze plains. Agricultural sources were the main anthropogenic P inputs, of which fertilizer P was the leading contributor and driver of P changes, but livestock manure also accounted for a high proportion. Presently, anthropogenic P inputs in the YRB are considerably higher than in other parts of the world. Although long-distance transportation allows some P from the entire basin to be deposited in freshwater, a large amount of P still reaches the estuary and has a negative effect on water quality, outweighing the influence of local coastal inputs. To maintain the ecological health of the river basin and estuary, it will be necessary to further improve P utilization efficiency and encourage greater cooperation between different regions in the river basin. [Display omitted] •P flux in river basin is characterized by high in the east and low in the west.•Agricultural sources contributed the most P inputs.•P inputs derived from aquaculture grows rapidly.•P inputs from the entire basin affects water quality of estuary more than the local.