Responses of Nutrients to the Precipitation Variation and Land Use in Subtropical Monsoonal Small Mountainous Rivers:A Case Study of Baixi Watershed  

作　　者：TIAN Yuan GAO Fei CAO Ke LV Shenghua DUAN Xiaoyong YIN Ping 

机构地区：[1]Qingdao Institute of Marine Geology,China Geological Survey,Ministry of Natural Resources,Qingdao 266237,China [2]Laboratory for Marine Geology,Laoshan Laboratory,Qingdao 266237,China

出　　处：《Journal of Ocean University of China》2024年第2期383-391,共9页中国海洋大学学报（英文版）

基　　金：financially supported by the Postdoctoral Foundation of Qingdao(Pb Isotopes of Oujiang River to Quantitatively Identify Sediment Provenance in Oujiang Estuary and Adjacent Area);the China Geological Survey Project(No.DD20190276);the Fund of Ministry of Science and Technology(Nos.2013FY112200 and 2019YFE0127200).

摘　　要：Small mountainous rivers are characterized by large instantaneous fluxes and susceptible to extreme weather events,which can rapidly transport materials into the sea and have a significant impact on the ecological environment of estuaries and bays.In order to investigate the seasonal characteristics of nutrients in small mountainous rivers in the subtropical monsoon region and the output pattern to the sea during heavy precipitation,surveys on the mountainous rivers were carried out in Baixi watershed in August 2020(wet season),March 2021(dry season)and June 2021(Meiyu period).The results showed that the dissolved inorganic nitrogen(DIN)of the rivers has an average concentration of 752μg L^(−1)in the wet season and 1472μg L^(−1)in the dry season.The concentrations of dissolved inorganic phosphorus(DIP)in wet season and dry season were 63μg L^(−1)and 51μg L^(−1),respectively.Influenced by the changes of land use in sub-watersheds,DIN concentrations in the mainstream increased from 701μg L^(−1)in the upper reaches to 1284μg L^(−1)in the middle reaches.Two rainstorms during the Meiyu period in the watershed caused the pulse runoff in the river.The maximum daily runoff reached 70 times that before rains.The maximum daily fluxes of DIN and DIP were 109 and 247 times that before rains,respectively.In view that the watershed experienced several rainstorms in the wet season,the river,with pulse runoff,carries a large amount of nutrients into the sea in a short time,which will have a significant impact on the environment of Sanmen bay and its adjacent sea.

关 键 词：small mountainous river uneven precipitation RAINSTORM pulse runoff nitrogen and phosphorus 

分 类 号：X143[环境科学与工程—环境科学] P342[天文地球—水文科学]