U.S. Rivers and Streams Super-Saturated
With Carbon Dioxide
Rivers and streams in the United States
are releasing substantially more carbon dioxide into the atmosphere than
previously thought. These findings could change the way scientists model
the movement of carbon between land, water, and the atmosphere.
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.
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 at http://www.usgs.gov/climate_landuse/land_carbon/default.asp.