2023-09-15 01:50:23
Rivers are warming and losing oxygen faster than oceans. Of almost 800 rivers studied in Europe and the US, warming occurred in 87% and oxygen loss in 70%.
Over the next 70 years, river systems, especially in the southern United States, will likely experience periods of such low oxygen levels that the rivers could “induce acute die-off” of certain fish species and threaten overall aquatic diversity.
The study, published in Nature Climate Change (1) by a team led by Penn State University, also predicts that, over the next 70 years, river systems, especially in the southern United States, will likely experience periods with such low oxygen levels that rivers could ” induce acute death” of certain fish species and threaten aquatic diversity in general.
“It’s a wake-up call,” said Li Li, Isett Professor of Civil and Environmental Engineering and author of the paper. “We know that a warming climate has caused warming and loss of oxygen in the oceans, but we didn’t expect this to happen.” occurred in large, shallow rivers.
Nearly 800 rivers throughout the US and central Europe
He highlights that “this is the first study to comprehensively analyze temperature changes and deoxygenation rates in rivers, and what we have discovered has important implications for water quality and the health of aquatic ecosystems around the world.” “, Add.
The international research team used artificial intelligence and deep learning approaches to reconstruct historically sparse water quality data from nearly 800 rivers across the United States and central Europe.
They discovered that heThe rivers are warming and deoxygenating faster than the oceans, which could have serious implications for aquatic life and human life.
River water temperatures and dissolved oxygen levels are essential measures of water quality and ecosystem health
“Rivers water temperature and dissolved oxygen levels are essential measures of water quality and ecosystem health,” said Wei Zhi, associate research professor in the Department of Civil and Environmental Engineering and lead author of the study. “However, they are not well understood because they are difficult to quantify due to the lack of consistent data in different rivers and the myriad of variables involved that can change oxygen levels in each basin.”
The research team developed novel deep learning approaches to reconstruct consistent data to enable systematic comparison across different rivers.
The Gulf of Mexico usually has dead zones in summer
“If you think about it, life in water depends on temperature and dissolved oxygen, the lifeline for all aquatic organisms,” says Li, who is also affiliated with the Institute of Energy and Environment. “We know that “Coastal areas, like the Gulf of Mexico, tend to have dead zones in the summer. What this study shows us is that this could also happen in rivers, because some will no longer support life as before.”
The decrease in oxygen in rivers, or deoxygenation, also drives the emission of greenhouse gases and causes the release of toxic metals
Urban rivers showed the most rapid warming, while agricultural rivers experienced the slowest warming but the most rapid deoxygenation
According to him, the decrease in oxygen in rivers, or deoxygenation, also drives the emission of greenhouse gases and causes the release of toxic metals.
To conduct their analysis, the researchers trained a computer model with a wide range of data – from annual precipitation rates to soil type and sunlight – from 580 rivers in the United States and 216 rivers in Central Europe. According to the model, 87% of rivers have warmed in the last four decades and 70% have lost oxygen.
The study revealed that urban rivers showed 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, in all the rivers studied, future deoxygenation rates were between 1.6 and 2.5 times higher than historical rates.
“The loss of oxygen in rivers is unexpected, because we normally assume that rivers do not lose as much oxygen as large bodies of water, such as lakes and oceans,” he emphasizes. “That was really alarming, because if the levels of oxygen drops low enough, it becomes dangerous to aquatic life.
Some fish species could become completely extinct
The model predicted that, in the next 70 years, some fish species could become completely extinct due to longer periods of low oxygen levels, which Li said would threaten overall aquatic diversity.
“Rivers are essential for the survival of many species, including our own, but have historically been overlooked as a mechanism for understanding climate change,” Li laments. everyone, and It’s disturbing.”
References (1) Widespread deoxygenation in warming rivers. Nature Climate Change.
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