基金We are grateful for the data provided by the shared Changjiang estuary voyage of the National Natural Science Foun- dation of China in the summer of 2013, and appreciate the coordination and cooperation with Wang Jianfeng, Lu Guangyuan, Qu Baoxiao, Yu Haiyan, Ding Ruibin, and the crew of the R/V Experiment No.3 during the field investigation. Special thanks are given to Shi Xiaoyong for providing the bottom DO data off the Changjiang estuary in the summer of 2002. We also thank the anonymous reviewers for their valuable comments and suggestions for revision. This study was supported by the National Natural Science Foundation of China （Grant Nos. 41206068 ＆ 41620104001） the National Natural Science Foundation--Shandong Province Joint Fund for Marine Science Research Center （Grant No. U1406403）+3 种基金 the Basic Scientific Fund for National Public Research Institutes of China （Grant No. 2016S/Q08） the Open Fund of the Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences and the Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology （Grant No. KLMEES201603） the National Basic Research Program of China （Grant No. 2010CB428703） and the National Project of Compre- hensive Investigation and Research of the Coastal Seas of China （Grant No. 908-ZC-I-03）.