Research reveals how global ecosystems produce greenhouse gas emissions

Icelandic researchers examine cotton in the river and record decomposition data. Their findings helped identify the drivers of river pollution. Credit: Oakland University

Biology researchers from Oakland University have teamed up with scientists around the world to understand the relationship between greenhouse gas emissions produced by ecosystems and environmental change. Their findings offer new methods and baseline information for tracking ecosystem changes as the earth warms.

Microbes such as bacteria and fungi naturally break down organic matter and release greenhouse gases, but ecosystems around the world are seeing changes in this process. Although decomposition is important in all ecosystems, environmental factors, such as nutrient pollution and warming, can alter decomposition rates, leading to changes in the release of greenhouse gases into the atmosphere.

“Nutrients such as nitrogen and phosphorus are essential for all life, but are added to water in excess, making it a globally significant source of pollution,” said the biology professor at OR, Scott Tiegs, Ph.D. says. “Our paper is the first to quantify the ability of rivers to remove nutrients from the water column on a global scale.”

Nutrient pollution can cause algal blooms in lake and marine ecosystems downstream, when the algae eventually decompose oxygen is used leading to large areas with little oxygen. These are called dead zones. In addition, nutrient pollution can affect the quality of available drinking water.

With a basic understanding of the drivers that alter decay rates, researchers set out to expand their research worldwide.

Initially, OU researchers worked in the OU Biological Reserve to develop methods to monitor the rate of carbon degradation in rivers. Cotton was their organic material of choice because it is made almost entirely of cellulose, the most abundant organic polymer on the planet. This makes UO’s research methods relevant to ecosystems around the world.

With a transferable method developed, Tiegs enlisted the help of researchers around the world to collect baseline data. An experiment of this magnitude had yet to be completed on the patterns and drivers of river decay. With the help of modern connectivity, around 150 researchers came together within a few months.

“We reached out through existing professional relationships and social media, just word of mouth,” Tiegs says. “It generated a lot of interest and the project grew rapidly.”

Then, identical materials from the UO’s methods were sent around the world for the researchers to collect data in their different environments. Experiments were conducted in 11 biomes, made up of more than 500 rivers.

The publication of their research provides researchers around the world with a baseline for further research into global pollution.

“The test [research methods] that we have developed can be applied in many other different contexts,” says Tiegs. “We have a proposal underway to target agricultural and urban systems and hopefully we can do this on an even larger scale.”

The research has been published in Global biogeochemical cycles.

Biology professor examines global river ecology

More information:

David M. Costello et al, Global Patterns and Controls of Nutrient Immobilization on Cellulose Decomposition in River Ecosystems, Global biogeochemical cycles (2022). DOI: 10.1029/2021GB007163

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Research reveals how global ecosystems produce greenhouse gas emissions (2022, March 8)
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