National Science Foundation
Press Release 11-220
Significant
amount of carbon in land is leaking into streams and rivers, then to the
atmosphere
http://www.nsf.gov/news/news_summ.jsp?cntn_id=121994&WT.mc_id=USNSF_51&WT.mc_ev=click
Rivers and streams in the
This according to researchers
publishing their results in the current issue of the journal Nature
Geoscience.
Their findings could change the way scientists
model the movement of carbon among land, water and the atmosphere.
"Direct measurements of carbon dioxide
concentrations and fluxes in streams and rivers are still extremely rare,"
said Henry Gholz, program director in the National
Science Foundation's (NSF) Division of Environmental Biology, which funded the
research.
"This study demonstrates that both are much
higher than assumed. The research should enable more predictive and precise
models of carbon cycling at regional to global scales."
The researchers found that a significant amount
of carbon contained in land, which first is absorbed by plants and forests
through the air, is leaking into streams and rivers and then released into the
atmosphere before reaching coastal waterways.
"What we are able to show is that there is a
source of atmospheric carbon dioxide from streams and rivers, and that it is
significant enough for terrestrial modelers to take note of it," said
David Butman, a co-author of the paper and scientist
at the Yale University School of Forestry & Environmental
Studies.
He and his co-author, ecologist Peter Raymond
also of Yale, analyzed data from samples of more than 4,000 rivers
and streams throughout the
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.
"These rivers breathe a lot of carbon,"
said Butman. "They are a source of carbon
dioxide, just like we breathe out carbon dioxide and like smokestacks emit
carbon dioxide.
"This has never been systematically
estimated from a region as large as the
The paper, titled "Significant Efflux of Carbon
Dioxide from Streams and Rivers in the United States," also indicates that
as the climate heats up there will be more rain and snow, and that an increase
in precipitation will result in even more terrestrial carbon flowing into
rivers and streams and being released into the atmosphere.
Any accurate estimate of carbon uptake vs.
carbon released must include the carbon in streams and rivers, Butman said.
The researchers note that currently it's
difficult to determine how to include this flux in regional carbon budgets,
because the influence of human activity on the release of carbon dioxide into
streams and rivers is still unknown.
The research was also funded by a NASA Earth and
Space Science Fellowship, a NASA Carbon & Ecosystems Program grant, and the
-NSF-