“Human Impact on Rivers: Accelerating Organic Matter Decomposition and Climate Change”

Humans may be accelerating the rate at which organic matter decomposes in rivers and streams on a global scale, according to a new study from the University of Georgia, Oakland University, and Kent State University. This could pose a threat to biodiversity in waterways around the world and increase the amount of carbon in Earth’s atmosphere, potentially exacerbating climate change.

The study, published in Science, is the first to combine a global experiment and predictive modeling to illustrate how human impacts to waterways may contribute to the global climate crisis. Krista Capps, an associate professor of ecology in the Odum School of Ecology at UGA and co-author of the study, expressed concern over the changes in river ecosystems caused by human activities. She highlighted that increases in decomposition rates may have negative implications for the global carbon cycle and the animals that rely on these ecosystems for survival.

Rivers and streams play a crucial role in the global carbon cycle by storing and decomposing large amounts of organic matter. However, human impacts such as urbanization and agriculture are altering the natural process of decomposition in these water bodies. Scott Tiegs, a professor of biological sciences at Oakland University and co-author of the study, emphasized that a significant amount of carbon dioxide and methane emissions come from aquatic ecosystems. When human activities disrupt the decomposition process, more carbon is released into the atmosphere, contributing to greenhouse gas pollution.

The researchers collected field data from 550 rivers worldwide, collaborating with over 150 researchers in 40 countries. By analyzing this data, they were able to estimate decomposition rates in rivers and streams across the globe, including understudied regions like the tropics. The team also developed a free online mapping tool that shows how different types of leaves decompose in local waterways.

Using predictive modeling, the researchers identified environmental factors responsible for increased decomposition rates, such as higher temperatures and nutrient concentrations. David Costello, an associate professor at Kent State University and co-author of the study, emphasized the importance of reducing human impacts on decomposition to keep more carbon in rivers and prevent it from entering the atmosphere.

Overall, the study underscores the need to address human activities that are altering decomposition rates in waterways. By reducing these impacts, we can improve water quality, protect biodiversity, and mitigate the effects of climate change. The findings of this research have significant implications for environmental conservation efforts worldwide.

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