Washington, Feb 10 : A new study has determined that carbon processing in rivers is a bigger component of global carbon cycling than previously believed, thus laying out a framework for how scientists should go about assessing those processes.
The study was conducted by Aaron Packman, associate professor of civil and environmental engineering in the McCormick School of Engineering and Applied Science, Northwestern University, US.
Packman's study is quite important as much more is known about carbon cycling in the atmosphere and oceans than in rivers.
Because evaluating large-scale material cycling in a river provides a challenge, much of what we know about carbon processing in rivers is based on what flows into the ocean.
"But that's not really enough," said Packman said. "You miss all this internal cycling," he added.
Therefore, in order to understand how carbon cycles around the globe - through the land, freshwater, oceans and atmosphere - scientists need to understand how it moves around, how it's produced, how it's retained in different places and how long it stays there.
In rivers, carbon is both transformed and consumed. Microorganisms like algae take carbon out of the atmosphere and incorporate it into their own cells, while bacteria eat dead organic matter and then release CO2 back into the atmosphere.
"It's been known for a long time that global carbon models don't really account for all the carbon," Packman said. "There's a loss of carbon, and one place that could be occurring is in river systems."
Even though river waters contain a small fraction of the total water on earth, they are such dynamic environments because microorganisms consume and transform carbon at rapid rates.
"We're evaluating how the structure and transport conditions and the dynamics of rivers create a greater opportunity for microbial processing," said Packman.
Packman's research team is currently working on a project funded by the National Science Foundation on the dynamics of organic carbon in rivers and trying to understand how carbon delivered from upstream areas influence the ecology of downstream locations. "The broadest idea is really part of global change efforts to understand carbon cycling over the whole Earth, which is an enormous challenge," said Packman.