The decline in river oxygen levels poses a severe threat to aquatic ecosystems, biodiversity, and freshwater species. Tropical rivers, already characterized by lower oxygen concentrations, are at heightened risk of hypoxia events, where oxygen levels become too low to sustain aquatic life. This could lead to significant disruptions in riverine ecosystems, affecting fish populations and other organisms that depend on these habitats. Additionally, the study found that heatwaves exacerbate oxygen depletion, further stressing these ecosystems. The impact of dam impoundments varies, with shallow reservoirs accelerating oxygen loss, while deeper reservoirs mitigate it in some cases. These findings highlight the compounded risks posed by climate change and human activities on river health.