Research shows rivers are rapidly warming and losing oxygen

Research shows rivers are rapidly warming and losing oxygen

Rivers are warming and losing oxygen faster than the ocean. Of the approximately 800 rivers studied in Europe and the United States, 87% experienced warming and 70% experienced oxygen loss.

The study, published in Nature Climate Change by a research team led by Penn State University, predicts that over the next 70 years, river systems, especially in the southern United States, are likely to experience periods of very low oxygen levels. It “induces acute mortality” in certain fish species and threatens aquatic biodiversity in general.

“This is a wake-up call,” said study author Lee Lee, Issett professor of civil and environmental engineering. “We know that climate warming is causing ocean warming and oxygen loss. But I didn’t expect this to happen.” This Will Happen” occurred in a large, shallow river.

“This is the first study to comprehensively analyze temperature changes and oxygen removal rates in rivers, and our findings have important implications for water quality and the health of aquatic ecosystems around the world,” he said. “There is,” he emphasized.

An international research team used artificial intelligence and deep learning approaches to reconstruct historically sparse water quality data from nearly 800 rivers in the United States and central Europe.

They found that rivers are warming and deoxygenating faster than the ocean, which could have serious implications for aquatic life and human life.

“River water temperature and dissolved oxygen levels are important measures of water quality and ecosystem health,” said Wei Ji, associate research professor in the School of Civil and Environmental Engineering and lead author of the study. It is difficult to quantify because of the lack of consistent data across different rivers and the myriad variables involved that can change oxygen levels in each basin. ”

The research team developed a new deep learning approach to reconstruct consistent data and enable systematic comparisons between different rivers.

“If you think about it, life in water depends on temperature and dissolved oxygen, which are the lifeblood of all aquatic life,” said Lee, who is also affiliated with the Institute for Energy and Environment. ”

He said the reduction of oxygen in rivers, or deoxygenation, also contributes to greenhouse gas emissions and the release of toxic metals.

To conduct their analysis, the researchers trained a computer model using a wide range of data from 580 rivers in the United States and 216 rivers in Central Europe, from annual precipitation to soil type to sunlight. did. According to the model, 87% of rivers have warmed and 70% have lost oxygen over the past 40 years.

The study found that urban rivers experienced the most rapid warming, while agricultural rivers experienced the slowest warming but the most rapid deoxygenation. They also used the model to predict future rates and found that future deoxygenation rates were 1.6 to 2.5 times higher than historical rates in all rivers studied.

“The loss of oxygen in rivers was unexpected, because we normally think that rivers do not lose as much oxygen as large bodies of water such as lakes and oceans,” he stressed. Masu. When it gets low enough, it becomes dangerous to aquatic life.

The model predicts that some fish species could become completely extinct over the next 70 years due to prolonged low oxygen levels, which would threaten the overall diversity of aquatic life, Lee said. Ta.

“Rivers are essential to the survival of many species, including our own, but they have historically been ignored as a mechanism for understanding climate change,” Lee laments. Uneasy.