Climate change is steadily stripping oxygen from rivers around the world, according to a new study published May 15 in Science Advances. Researchers found that this long-term oxygen decline is happening across most river systems, with tropical rivers emerging as the most vulnerable. The findings point to an urgent need for strategies aimed at slowing oxygen loss in freshwater ecosystems.
The study was led by Prof. Kun Shi of the Nanjing Institute of Geography and Limnology (NIGLAS) at the Chinese Academy of Sciences. Dr. Qi Guan served as the first author, and the project also involved a researcher from Tongji University.
Rivers Losing a Vital Ingredient for Life
Dissolved oxygen plays a critical role in maintaining healthy river ecosystems. It supports aquatic organisms, helps sustain biodiversity, and influences important biogeochemical processes. When oxygen levels fall, river health can deteriorate, putting fish and other freshwater species at risk.
To examine how river oxygen levels have changed over time, the researchers used a machine-learning stacking algorithm to analyze observations from 21,439 river reaches worldwide collected over nearly four decades (1985-2023).
