Sustained deoxygenation in global flowing waters under climate warming
Qi Guan1, Kun Shi1, Xuehui Pi2
1Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Science Advances
|May 15, 2026
Summary
Global rivers are experiencing significant deoxygenation, with over 78% showing declining dissolved oxygen (DO) levels. This trend, driven by temperature and solubility, threatens aquatic ecosystems and requires urgent mitigation strategies.
Area of Science:
- Environmental Science
- Hydrology
- Ecology
Background:
- Dissolved oxygen (DO) is crucial for aquatic ecosystems.
- Global oceans, lakes, and coastal waters show declining DO.
- Understanding riverine DO changes globally is challenging.
Purpose of the Study:
- To estimate global river DO concentrations from 1985-2023.
- To analyze patterns and trends in fluvial deoxygenation.
- To provide a baseline for mitigating deoxygenation threats.
Main Methods:
- Utilized Landsat observations and climatic data.
- Estimated DO concentrations for 21,439 global river segments.
- Analyzed trends and projected future DO levels.
Main Results:
- Global rivers show sustained deoxygenation at -0.045 mg/L/decade.
- 78.8% of rivers experienced deoxygenation.
- Oxygen solubility and temperature are primary drivers; heatwaves and dams also influence DO.
Conclusions:
- Global fluvial deoxygenation is a widespread and escalating issue.
- Future projections indicate continued DO decline under various emissions scenarios.
- Targeted measures are essential to protect riverine ecosystem health.
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