Rivers are Rapidly Warming, Losing Oxygen; Aquatic Life at Risk
Published:07 Nov.2023 Source:Penn State
Rivers are warming and losing oxygen faster than oceans, according to a Penn State-led study published today (Sept. 14) in the journal Nature Climate Change. The study shows that of nearly 800 rivers, warming occurred in 87% and oxygen loss occurred in 70%. The study also projects that within the next 70 years, river systems, especially in the American South, are likely to experience periods with such low levels of oxygen that the rivers could "induce acute death" for certain species of fish and threaten aquatic diversity at large.
The international research team used artificial intelligence and deep learning approaches to reconstruct historically sparce water quality data from nearly 800 rivers across the U.S. and central Europe. They found that rivers are warming up and deoxygenating faster than oceans, which could have serious implications for aquatic life -- and the lives of humans. The National Oceanic and Atmospheric Administration estimates that most Americans reside within a mile of a river or stream. Declining oxygen in rivers, or deoxygenation, also drives the emission of greenhouse gases and leads to the release of toxic metals.
To conduct their analysis, the researchers trained a computer model on a vast range of data -- from annual precipitation rates to soil type to sunlight -- for 580 rivers in the United States and 216 rivers in Central Europe. The model found that 87% of the rivers have been getting warmer in the past four decades and 70% have been losing oxygen. The study revealed that urban rivers demonstrated the most rapid warming, whereas agricultural rivers experienced the slowest warming but fastest deoxygenation. The model predicted that, within the next 70 years, certain species of fish could die out completely due to longer periods of low oxygen levels, which would threaten aquatic diversity broadly.