Export of dissolved carbonaceous and nitrogenous substances in rivers of the “Water Tower of Asia”  

作　　者：Bin Qu Mika Sillanpaa Shichang Kang Fangping Yan Zhiguo Li Hongbo Zhang Chaoliu Li 

机构地区：[1]Laboratory of Green Chemistry, Lappeenranta University of Technology, Mikkeli 50130, Finland [2]Key Laboratory of Tibetan Enuironment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China [3]State Key Laboratory of Cryospheric Sciences Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China [4]Shangqiu Normal University, Shangqiu, He'nan 476000, China [5]CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100085, China

出　　处：《Journal of Environmental Sciences》2018年第3期53-61,共9页环境科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.41675130, 41271015, 41225002);the Academy of Finland (decision number: 268170);the State Key Laboratory of Cryospheric Science (SKLCS-ZZ-2008-01 and SKLCS-OP-2014-05)

摘　　要：Rivers are critical links in the carbon and nitrogen cycle in aquatic,terrestrial,and atmospheric environments.Here riverine carbon and nitrogen exports in nine large rivers on the Tibetan Plateau—the＂Water Tower of Asia＂—were investigated in the monsoon season from 2013 to 2015.Compared with the world average,concentrations of dissolved inorganic carbon（DIC,30.7 mg/L）were high in river basins of the plateau due to extensive topographic relief and intensive water erosion.Low concentrations of dissolved organic carbon（DOC,1.16 mg/L）were likely due to the low temperature and unproductive land vegetation environments.Average concentrations of riverine DIN（0.32 mg/L）and DON（0.35 mg/L）on the Tibetan Plateau were close to the world average.However,despite its predominantly pristine environment,discharge from agricultural activities and urban areas of the plateau has raised riverine N export.In addition,DOC/DON ratio（C/N,~6.5）in rivers of the Tibetan Plateau was much lower than the global average,indicating that dissolved organic carbon in the rivers of this region might be more bioavailable.Therefore,along with global warming and anthropogenic activities,increasing export of bioavailable riverine carbon and nitrogen from rivers of the Tibetan Plateau can be expected in the future,which will possibly influence the regional carbon and nitrogen cycle.Rivers are critical links in the carbon and nitrogen cycle in aquatic,terrestrial,and atmospheric environments.Here riverine carbon and nitrogen exports in nine large rivers on the Tibetan Plateau—the＂Water Tower of Asia＂—were investigated in the monsoon season from 2013 to 2015.Compared with the world average,concentrations of dissolved inorganic carbon（DIC,30.7 mg/L）were high in river basins of the plateau due to extensive topographic relief and intensive water erosion.Low concentrations of dissolved organic carbon（DOC,1.16 mg/L）were likely due to the low temperature and unproductive land vegetation environments.Average concentrations of riverine DIN（0.32 mg/L）and DON（0.35 mg/L）on the Tibetan Plateau were close to the world average.However,despite its predominantly pristine environment,discharge from agricultural activities and urban areas of the plateau has raised riverine N export.In addition,DOC/DON ratio（C/N,~6.5）in rivers of the Tibetan Plateau was much lower than the global average,indicating that dissolved organic carbon in the rivers of this region might be more bioavailable.Therefore,along with global warming and anthropogenic activities,increasing export of bioavailable riverine carbon and nitrogen from rivers of the Tibetan Plateau can be expected in the future,which will possibly influence the regional carbon and nitrogen cycle.

关 键 词：Dissolved carbon Dissolved nitrogen RIVERS The Tibetan Plateau 

分 类 号：X131.2[环境科学与工程—环境科学]