22 May 2018: Analysis of plant litter in seasonal streams has revealed the world’s river systems could be releasing much higher levels of carbon dioxide into the atmosphere than previously thought.
University of Canberra fresh water expert Dr Fiona Dyer recently participated in the first global study of the contribution that intermittent rivers – rivers that don’t flow all year round – make to carbon cycling.
The research, published in the scientific journal Nature Geoscience, found that intermittent rivers could increase daily carbon dioxide emissions from river networks by up to 152 per cent.
Dr Dyer said that previously, intermittent streams have not been considered when measuring how much the world’s river networks contribute to the release of carbon dioxide. She said their exclusion has led to a notable underestimation.
“A project of this scale is rare,” Dr Dyer, from the University’s Institute for Applied Ecology, said. “Collectively, we gathered more than 200 samples from around the world.
“By analysing such a number of samples, we have shown that these types of rivers are really important and significant contributors to global carbon dioxide levels.
“If we overlook these rivers, we essentially ignore emissions from at least 84,000 km of river channels.
“The project demonstrates that re-wetting of intermittent rivers is an important parameter to consider when applying carbon dioxide estimates to climate models.
“In turn, we need to better understand how our changing climate will increase the number of intermittent rivers, as well as impact the frequency and magnitude of re-wetting events.”
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