Submarine groundwater discharge and seasonal hypoxia off the Changjiang River Estuary

• Published in: Acta oceanologica Sinica Vol. 42; no. 8; pp. 125 - 133
• Main Authors: Zhu, Tianyi, Xu, Bochao, Guo, Xiaoyi, Wei, Qinsheng, Lian, Ergang, Liu, Pengxia, Burnett, William C., Yao, Qingzhen, Yu, Zhigang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2023; Springer Nature B.V; Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China; Academy of the Future Ocean,Ocean University of China,Qingdao 266100,China%Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education,Ocean University of China,Qingdao 266100,China; College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China%Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China; Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education,Ocean University of China,Qingdao 266100,China; Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China%Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education,Ocean University of China,Qingdao 266100,China; Key Laboratory of Marine Eco-Environmental Science and Technology,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266100,China%Research Center for Monitoring and Environmental Sciences,Taihu Basin and East China Sea Ecological Environment Supervision and Administration Authority,Ministry of Ecology and Environment,Shanghai 200120,China; College of Chemistry and Chemical Engineering,Ocean University of China,Qingdao 266100,China; State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China%Research Center for Monitoring and Environmental Sciences,Taihu Basin and East China Sea Ecological Environment Supervision and Administration Authority,Ministry of Ecology and Environment,Shanghai 200120,China%Department of Earth,Ocean and Atmospheric Science,Florida State University,Tallahassee FL 32306,USA
• Subjects: Climatology; Discharge; Dissolved oxygen; Earth and Environmental Science; Earth Sciences; Ecology; Engineering Fluid Dynamics; Environmental Chemistry; Environmental science; Estuaries; Estuarine dynamics; Fluxes; Groundwater; Groundwater discharge; Hypoxia; Laboratories; Marine & Freshwater Sciences; Mass balance; Mass balance models; Nutrients; Oceanography; Oxygen; Radon isotopes; Rivers; Seasons; Seawater; Stratigraphy; Summer; hypoxia; Rn; submarine groundwater discharge; Ra; 226Ra; 222Rn
• ISSN: 0253-505X; 1869-1099
• DOI: 10.1007/s13131-023-2256-9

Hypoxia is a common phenomenon in the sea adjacent to the Changjiang River Estuary (CJE), one of the global major estuaries. Submarine groundwater discharge (SGD) is a widely recognized pathway for terrestrial materials entering the sea, and has been found to be significant off the CJE. We used a 222 Rn mass balance model to estimate the SGD fluxes off the CJE and showed that it is linked to seasonal dissolved oxygen (DO) variations. Average SGD fluxes were estimated to be (0.012 ± 0.010) m 3 /(m 2 ·d) in winter, (0.034 ± 0.015) m 3 /(m 2 ·d) in summer, and (0.020 ± 0.010) m 3 /(m 2 ·d) in autumn. We found a significant negative correlation between DO concentrations and SGD rates with groundwater discharge being highest in the summer flood season. In addition, distribution patterns of SGD and hypoxia zones in summer are spatially overlapped, indicating that SGD is an important contributor to summer hypoxia in this region.