Syracuse Sun

University researchers are studying the impact of climate warming and population growth on the chemical composition of U.S. rivers. They are using a combination of traditional geochemistry and artificial intelligence to predict changes in alkalinity and salt levels. The research was led by Tao Wen, an assistant professor at the College of Arts and Sciences’ Department of Earth and Environmental Sciences, and published in Applied Geochemistry.

The research team is investigating how climate change and human activities influence river chemistry. An excess of salt in rivers can make water undrinkable, increase treatment costs, and harm wildlife. Past research has found that increased salt levels in rivers lead to higher alkalinity, which can damage aquatic life and increase treatment challenges. However, alkalinity can help remove carbon dioxide from the atmosphere and mitigate climate warming.

Wen's team used machine learning models to project changes in salinity, measured by sodium levels, and alkalinity in 226 rivers across the U.S. between 2040 and 2100 under different climate and human population scenarios. In northern states, warmer winters could reduce the need for road salting, making rivers less salty. In the South and West, where little road salt is used, river salinity is expected to remain the same. However, as these regions become hotter and drier, salt from the soil may wash into waterways.

The study also examines the effect of rising temperatures on alkalinity. In carbonate rock-rich watersheds, alkalinity decreases when temperatures exceed 10 degrees Celsius. Conversely, in silicate rock or organic carbon-rich watersheds, higher temperatures increase alkalinity levels. Rainfall also affects the chemical composition of rivers, but only to a certain extent. The findings suggest that in the future, some watersheds may be managed to increase their capacity to absorb carbon from the atmosphere.

For his work, Tao Wen received the 2025 Emerging Investigator Series award from the International Association of Geochemistry for his contributions to the field of geochemistry. This award recognizes early-career researchers whose work provides new insights or promotes geochemical applications.

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