From the water sources of the Tibetan Plateau to the ocean:State of nutrients in the Changjiang linked to land use changes and climate variability  

作　　者：Jing ZHANG Guosen ZHANG Yanan DU Anyu ZHANG Yan CHANG Yingchun ZHOU Zhuoyi ZHU Ying WU Zaifeng ZHANG Sumei LIU 

机构地区：[1]State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China [2]Yangze River Estuary Survey Bureau of Hydrology and Water Resource,CWRC,Shanghai 200136.China [3]KLATASDS-MOE,School of Statistics,East China Normal University,Shanghai 200241,China [4]Nantong Environmental Monitoring Center,Ministry of Ecology and Environment,Nantong 226006,China [5]Key Laboratory of Marine Chemistry Theory and Technology,Ocean University of China,Qingdao 266100,China [6]School of Oceanography,Shanghai Jiao Tong University Shanghai 200030,China

出　　处：《Science China Earth Sciences》2022年第11期2127-2174,共48页中国科学（地球科学英文版）

基　　金：funded by the National Natural Science Foundation of China through the“Creative Research Team”on“Land-Sea Interactions in Highly Turbid Estuaries and Adjacent Coastal Environments”(Grant Nos.40721004 and 41021064)。

摘　　要：Anthropogenic activity is an important driver of changes in the chemistry of nutrients(N,P,and Si)over watersheds at the sub-continental scale(e.g.,106km~2)and can markedly modify their seaward fluxes to the global ocean.In the present study,we reviewed the current status of nutrient chemistry in Changjiang(Yangtze River)based on data collected through 11 expeditions along a river course spanning 4,500 km and 15–20 major tributaries during 1997–2016 as well as monthly monitoring at the river mouth since 1980.The data were analyzed together with published results in the literature to synthesize the recent developments and current state of nutrients in the Changjiang.Previously published results from the Qinghai-Tibetan Plateau head waters were included to realize the systematics of nutrients for the whole drainage basin.Here,we showed that tributaries of the upper reaches of watersheds collectively determine the regime with high concentration and skewed species ratio of nutrients in the Changjiang mainstream,producing profound effects over a water course of 2,000–2,500 km further downstream and until the river mouth.Moreover,using data across the Three Gorges Reservoir(TGR)during 2003–2016,we evaluated the trapping and/or amplifying effects of the Three Gorges Dam(TGD)on nutrient chemistry.Tide-influenced river delta contributed an additional 20%dissolved inorganic phosphorus and 5–10%dissolved inorganic nitrogen and dissolved silicates to the seaward flux,dramatically affecting the stoichiometry of nutrients at the river mouth.Next,based on compiled data on supply and export,legacy nutrients were evaluated.Both nitrogen and phosphorus are in the accumulation phase over the watersheds,and the legacy nutrient fluxes are much higher than the annual riverine seaward fluxes.Finally,we demonstrated that the seaward fluxes of anthropogenic nutrients from the Changjiang exceed those from other top 10 largest rivers on this planet,which can be attributed to land use changes in the China over the last three to fo

关 键 词：CHANGJIANG Nutrient chemistry Species ratio FLUXES Global river systems Hysteresis effect Legacy contributions 

分 类 号：P467[天文地球—大气科学及气象学]