作者：Guan, Q., Shi, K. & Pi, X.

Dissolved oxygen (DO), as a vital material sustaining aquatic ecosystems, has declined markedly in oceans, lakes, and coastal waters, yet unbiased understandings of changing DO concentrations in each individual river segment globally remain a challenge. Here, we estimate DO concentrations in 21,439 rivers globally between 1985 and 2023, based on Landsat observations and climatic data, and examine their patterns and trends. We find sustained deoxygenation in global rivers, at a rate of -0.045 mg liter(-1) decade(-1), with 78.8% experiencing fluvial deoxygenation, driven mainly by oxygen solubility and temperature. Moreover, short-term heatwaves and dam impoundment exert non-neglecting influence on these changes. Future projections demonstrate that global fluvial DO concentrations decline by 1.1% +/- 1.6% under SSP1-2.6 and 4.7% +/- 2.7% under SSP5-8.5 throughout the 21st century. Our study provides an unbiased baseline for escalating deoxygenation in global fluvial ecosystems that underscores targeted measures to mitigate deoxygenation threats and protect ecosystem health.

溶解氧（DO）是维持水生生态系统的重要物质，但其浓度在海洋、湖泊和近岸水域已显著下降；而对全球各河段溶解氧浓度变化的无偏认知仍是一项挑战。研究基于Landsat遥感观测与气候数据，估算了1985—2023年全球21439条河流的溶解氧浓度，并分析了其空间格局与变化趋势。发现全球河流正经历持续的脱氧过程，速率达每十年 -0.045 mg·L⁻¹，其中78.8%的河段呈脱氧趋势，其主要驱动因素为氧气溶解度与温度。此外，短期热浪与水库蓄水对上述变化也具有不可忽视的影响。未来情景预估显示，在整个21世纪，全球河流溶解氧浓度在SSP1-2.6情景下将下降1.1% ± 1.6%，在SSP5-8.5情景下将下降4.7% ± 2.7%。本研究为全球河流生态系统日益加剧的脱氧趋势提供了无偏基线，强调需采取有针对性的措施以减缓脱氧威胁、保护生态系统健康。

（来源：Science Advances 2026 Issue 20 DOI:10.1126/sciadv.aef3132）