ORIGINAL RESEARCH article
Front. Mar. Sci.
Sec. Coastal Ocean Processes
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1600636
Physical and biogeochemical processes in controlling the seasonal variation of dissolved oxygen in the Bohai and Yellow Seas
Provisionally accepted
- 1Tianjin Key Laboratory for Marine Environmental Research and Service, School of Marine Science and Technology, Tianjin University, Tianjin, China
- 2College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Deoxygenation in coastal seas has significant implications to the marine ecosystems. In this study, the processes influencing the seasonal variation of dissolved oxygen (DO) in the Bohai and Yellow Seas (BS and YS) are investigated using a coupled physical-biogeochemical model. The seasonal variation of the DO concentration ([DO]) in the surface water is lower in summer and autumn and higher in winter and spring, which is mainly controlled by temperature. Moreover, in this layer, photosynthesis, to some extent regulates the [DO], and leads to the supersaturation in summer, while downward diffusion in autumn is mainly responsible for the gradually decreased saturation degree. The seasonal distribution of the [DO] in the bottom water is similar with that in the surface water, with much lower [DO] and significant undersaturation in summer in the BS, and in summer and autumn in the YS. Vertical diffusion is overall the predominant source of DO in the bottom layer, while biological oxygen consumption (BOC) is the main sink, especially during stratification. Relative to the BS, the YS experiences a moderate but longer deoxygenation duration, due to the thicker bottom water and persistent stratification. In addition, it reveals that apparent oxygen utilization (AOU) prevalently underestimates BOC in coastal waters, and true oxygen utilization (TOU) is proposed as a more accurate proxy. Notably, the TOU-AOU discrepancy is strongly correlated with temperature variation during this period, suggesting continuous temperature monitoring as an useful pathway in investigating BOC in shallow estuarine and coastal waters.
Keywords: dissolved oxygen, Seasonal variation, Photosynthesis, Biological oxygen consumption, True oxygen utilization, Coupled physical-biogeochemical model, Bohai and Yellow Seas
Received: 26 Mar 2025; Accepted: 02 May 2025.
Copyright: © 2025 Zhang, Zhang, Song, Zhao and Wei. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Haiyan Zhang, Tianjin Key Laboratory for Marine Environmental Research and Service, School of Marine Science and Technology, Tianjin University, Tianjin, China
Guisheng Song, Tianjin Key Laboratory for Marine Environmental Research and Service, School of Marine Science and Technology, Tianjin University, Tianjin, China
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.