Submarine groundwater discharge and associated nutrient fluxes in the Greater Bay Area, China revealed by radium and stable isotopes

作     者：Qianqian Wang Xuejing Wang Kai Xiao Yan Zhang Manhua Luo Chunmiao Zheng Hailong Li Qianqian Wang;Xuejing Wang;Kai Xiao;Yan Zhang;Manhua Luo;Chunmiao Zheng;Hailong Li

作者机构：State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution ControlSchool of Environmental Science and EngineeringSouthern University of Science and TechnologyShenzhenGuangdong 518055China School of Environmental Science and EngineeringGuangdong Provincial Key Laboratory of Soil and Groundwater Pollution ControlSouthern University of Science and TechnologyShenzhenGuangdong 518055China MOE Key Laboratory of Groundwater Circulation&Environment Evolution and School of Water Resources and EnvironmentChina University of Geosciences(Beijing)Beijing 100083China 

出 版 物：《Geoscience Frontiers》 (地学前缘（英文版）)

年 卷 期：2021年第12卷第5期

页      面：397-410页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 08[工学] 0815[工学-水利工程] 

基　　金：supported by the National Natural Science Foundations of China(Nos.41890852,42077173) the Shenzhen Science and Technology Innovation Committee(No.JCYJ20190809142417287) State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control 

主　　题：Radium isotopes Stable isotopes Submarine fresh groundwater discharge Nutrients Coastal aquifers Pearl River estuary 

摘      要：The estuary-bay system is a common and complex coastal ***,quantifying submarine groundwater discharge(SGD)and associated nutrient fluxes in the complex coastal environment is challenging due to more dynamic and complicated riverine discharge,ocean processes and human *** this study,SGD and SFGD(submarine fresh groundwater discharge)fluxes were evaluated by combining stable and radium isotopes in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA),a typical estuary-bay *** first built a spatially distributed radium mass balance model to quantify SGD fluxes in coastal areas of GBA integrating the Pearl River Estuary(PRE),bays and *** then used the stable water isotope(d2 H and d18O)end-member mixing model to distinguish submarine fresh groundwater discharge(SFGD)from *** on the 228Ra mass balance,the estimated SGD fluxes in the PRE,adjacent bay,and shelf areas were(6.14±2.74)×10^(8) m^(3) d^(-1),(3.00±1.11)×10^(7) m^(3) d^(-1),and(5.00±5.64)×10^(8) m^(3) d^(-1),*** showed that the largest area-averaged SGD was in the PRE,followed by that in the adjacent shelf and the *** differences may be mainly influenced by ocean forces,urbanization and benthic topographies controlling the variability of groundwater ***,the three end-member mixing model of ^(228)Ra and salinity was developed to confirm the validity of the estimated SGD using the Ra mass balance *** the two models,groundwater endmember and water apparent age estimation were the main sources of uncertainty in *** estimated SFGD flux was(1.39±0.76)
108 m^(3) d^(-1),which accounted for approximately 12%of the total *** stable and radium isotopes was a useful method to estimate groundwater ***,the estimated SGD associated dissolved inorganic nitrogen(DIN)flux was one order of magnitude higher than other DIN *** was considered to be a significant contributor to the DIN loading to the *** findings