|Stream lines form a tangled web in this image derived from a set of data on water flow. Credit: David Butman, Yale University|
Oct. 26, 2011 -- Rivers and streams in the United States are releasing substantially more carbon dioxide into the atmosphere than previously thought, according to recent findings by David Butman and Professor Peter Raymond of the Yale School of Forestry and Environmental Studies.
The findings, part of Butman's PhD thesis, could change the way scientists model the movement of carbon between land, water, and the atmosphere.
Butman and Raymond found that a significant amount of carbon accumulated by plant growth on land is decomposed, discharged into streams and rivers, and outgassed as carbon dioxide (CO2) into the atmosphere. It is estimated that streams and rivers release almost 100 million metric tons of carbon each year. This release is equal to a car burning 40 billion gallons of gasoline, enough to drive back and forth to the moon 3.4 million times.
Water chemistry data from more than 4,000 rivers and streams throughout the United States were incorporated with detailed geospatial data to model the flux of carbon dioxide from water. The river and stream samples were collected at USGS gaging stations and the geospatial data was produced by both the USGS and EPA.
This research is being incorporated into the USGS LandCarbon effort to characterize the current and future fluxes of carbon influenced by both natural and anthropogenic processes. One part of this effort is looking at the potential for carbon storage in the Nation's vegetation, soils, and sediments, which is known as biological carbon sequestration.
For more information on that project, visit the National Assessment of Ecosystem Carbon Sequestration and Greenhouse Gas Fluxes website: http://www.usgs.gov/climate_landuse/land_carbon/default.asp.
The findings were recently published in a Nature Geoscience article entitled "Significant efflux of carbon dioxide from streams and rivers in the United States" by David Butman and Professor Peter Raymond of the Yale School of Forestry and Environmental Studies, as part of David's Ph.D. thesis. Funding for the study was from NASA, NSF, and the USGS. The article can be found at http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo1294.html.