title: Intensification of phosphorus cycling in China since the 1600s.
abstract: Phosphorus (P) is an essential nutrient for living systems with emerging sustainability challenges related to supply uncertainty and aquatic eutrophication. However, its long-term temporal dynamics and subsequent effects on freshwater ecosystems are still unclear. Here, we quantify the P pathways across China over the past four centuries with a life cycle process-balanced model and evaluate the concomitant potential for eutrophication with a spatial resolution of 5 arc-minutes in 2012. We find that P cycling in China has been artificially intensified during this period to sustain the increasing population and its demand for animal protein-based diets, with continuous accumulations in inland waters and lands. In the past decade, China's international trade of P involves net exports of P chemicals and net imports of downstream crops, specifically soybeans from the United States, Brazil, and Argentina. The contribution of crop products to per capita food P demand, namely, the P directly consumed by humans, declined from over 98% before the 1950s to 76% in 2012, even though there was little change in per capita food P demand. Anthropogenic P losses to freshwater and their eutrophication potential clustered in wealthy coastal regions with dense populations. We estimate that Chinese P reserve depletion could be postponed for over 20 y by more efficient life cycle P management. Our results highlight the importance of closing the P cycle to achieve the cobenefits of P resource conservation and eutrophication mitigation in the world's most rapidly developing economy.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China;
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China;
authors.forename: Hu
authors.initials: H
authors.lastname: Sheng
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China;
authors.forename: Songyan
authors.initials: S
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China; yuanzw@nju.edu.cn.
authors.forename: Zengwei
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: GIS Centre, Ryan Institute and School of Geography and Archaeology, National University of Ireland, Galway H91 CF50, Ireland;
authors.forename: Chaosheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287.
authors.forename: James J
authors.initials: JJ
authors.lastname: Elser
mesh_terms: D000465:Algorithms; D000818:Animals; D002681:China; D003247:Conservation of Natural Resources / Q000379:methods / Q000639:trends; D018556:Crops, Agricultural / Q000737:chemistry*; D017753:Ecosystem; D005068:Eutrophication; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology; D005843:Geography; D006801:Humans; D008962:Models, Theoretical; D010758:Phosphorus / Q000032:analysis* / Q000378:metabolism
chemical_list: D010758:Phosphorus
keywords: eutrophication; food production; industrial ecology; phosphorus cycling; sustainability