Many people are watching their carbon footprint these days, but a recently published article identifies a new and unexpected source of carbon dioxide in the atmosphere: rivers and streams. Published in Nature Geoscience, the article by David Butman and Peter Raymond of the Yale School of Forestry and Environmental Studies could require changes to the current models of carbon movement throughout the atmosphere.
Carbon can be sequestered in vegetation and in the soil itself. Not only can streams and rivers flush carbon from the soil, but also the carbon taken in by plants can be released into rivers and streams as the plants decompose, eventually being discharged into the atmosphere as carbon dioxide. The authors estimate that nationwide, 100 million metric tons of carbon are released from rivers and streams annually—an amount equivalent to that released by vehicles burning 40 billion gallons of gasoline.
The authors used US Geological Survey water-chemistry data from more than 4,000 streams and rivers, as well as geospatial data from the USGS and EPA. The research is already being incorporated into the USGS LandCarbon project, which characterizes carbon fluxes from natural and manmade sources.