Featured Research

from universities, journals, and other organizations

Global rivers emit three times IPCC estimates of greenhouse gas nitrous oxide

Date:
December 27, 2010
Source:
National Science Foundation
Summary:
Biologists have demonstrated that streams and rivers receiving nitrogen from urban and agricultural land uses are a significant source of nitrous oxide to the atmosphere.

Scientists collect stream water samples on a golf course near Jackson Hole, Wyoming.
Credit: Jake Beaulieu

What goes in must come out, a truism that now may be applied to global river networks. Human-caused nitrogen loading to river networks is a potentially important source of nitrous oxide emission to the atmosphere. Nitrous oxide is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction.

Related Articles


It happens via a microbial process called denitrification, which converts nitrogen to nitrous oxide and an inert gas called dinitrogen.

When summed across the globe, scientists report this week in the journal Proceedings of the National Academy of Sciences (PNAS), river and stream networks are the source of at least 10 percent of human-caused nitrous oxide emissions to the atmosphere.

That's three times the amount estimated by the Intergovernmental Panel on Climate Change (IPCC).

Rates of nitrous oxide production via denitrification in small streams increase with nitrate concentrations.

"Human activities, including fossil fuel combustion and intensive agriculture, have increased the availability of nitrogen in the environment," says Jake Beaulieu of the University of Notre Dame and the U.S. Environmental Protection Agency in Cincinnati, Ohio, and lead author of the PNAS paper.

"Much of this nitrogen is transported into river and stream networks," he says, "where it may be converted to nitrous oxide, a potent greenhouse gas, via the activity of microbes."

Beaulieu and co-authors measured nitrous oxide production rates from denitrification in 72 streams draining multiple land-use types across the United States. Their work was part of a broader cross-site study of nitrogen processing in streams.

"This multi-site experiment clearly establishes streams and rivers as important sources of nitrous oxide," says Henry Gholz, program director in NSF's Division of Environmental Biology, which funded the research.

"This is especially the case for those draining nitrogen-enriched urbanized and agricultural watersheds, highlighting the importance of managing nitrogen before it reaches open water," Gholz says. "This new global emission estimate is startling."

Atmospheric nitrous oxide concentration has increased by some 20 percent over the past century, and continues to rise at a rate of about 0.2 to 0.3 percent per year.

Beaulieu and colleagues, say the global warming potential of nitrous oxide is 300-fold greater than carbon dioxide.

Nitrous oxide accounts for some six percent of human-induced climate change, scientists estimate.

They believe that nitrous oxide is the leading human-caused threat to the atmospheric ozone layer, which protects Earth from harmful ultraviolet radiation from the Sun.

Researchers had estimated that denitrification in river networks might be a globally important source of human-derived nitrous oxide, but the process had been poorly understood, says Beaulieu, and estimates varied widely.

While more than 99 percent of denitrified nitrogen in streams is converted to the inert gas dinitrogen rather than nitrous oxide, river networks are still leading sources of global nitrous oxide emissions, according to the new results.

"Changes in agricultural and land-use practices that result in less nitrogen being delivered to streams would reduce nitrous oxide emissions from river networks," says Beaulieu.

The findings, he and co-authors hope, will lead to more effective mitigation strategies.

Other authors of the paper are: Jennifer Tank of the University of Notre Dame; Stephen Hamilton of Michigan State University; Wilfred Wollheim of the University of New Hampshire; Robert Hall of the University of Wyoming; Patrick Mulholland of Oak Ridge National Laboratory and the University of Tennessee; Bruce Peterson of Marine Biological Laboratory in Woods Hole, Mass.; Linda Ashkenas of Oregon State University; Lee Cooper of the Chesapeake Biological Laboratory in Solomons, Md.; Clifford Dahm of the University of New Mexico; Walter Dodds of Kansas State University; Nancy Grimm of Arizona State University; Sherri Johnson of the U.S. Forest Service in Corvallis, Ore.; William McDowell of the University of New Hampshire; Geoffe Poole of Montana State University; HM Valett of Virginia Polytechnic Institute and State University; Clay Arango of Central Washington University; Melody Bernot of Ball State University; Amy Burgin of Wright State University; Chelsea Crenshaw of the University of New Mexico; Ashley Helton of the University of Georgia; Laura Johnson of Indiana University; Jonathan O'Brien of the University of Canterbury in Christchurch, New Zealand; Jody Potter of the University of New Hampshire; Richard Sheibley of the University of Notre Dame and the U.S. Geological Survey in Tacoma, Washington; Daniel Sobota of Washington State University; and Suzanne Thomas of the Marine Biological Laboratory in Woods Hole, Mass.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. J. Beaulieu, J. L. Tank, S. K. Hamilton, W. M. Wollheim, R. O. Hall, P. J. Mulholland, B. J. Peterson, L. R. Ashkenas, L. W. Cooper, C. N. Dahm, W. K. Dodds, N. B. Grimm, S. L. Johnson, W. H. McDowell, G. C. Poole, H. M. Valett, C. P. Arango, M. J. Bernot, A. J. Burgin, C. L. Crenshaw, A. M. Helton, L. T. Johnson, J. M. O'Brien, J. D. Potter, R. W. Sheibley, D. J. Sobota, S. M. Thomas. Nitrous oxide emission from denitrification in stream and river networks. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1011464108

Cite This Page:

National Science Foundation. "Global rivers emit three times IPCC estimates of greenhouse gas nitrous oxide." ScienceDaily. ScienceDaily, 27 December 2010. <www.sciencedaily.com/releases/2010/12/101220150944.htm>.
National Science Foundation. (2010, December 27). Global rivers emit three times IPCC estimates of greenhouse gas nitrous oxide. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2010/12/101220150944.htm
National Science Foundation. "Global rivers emit three times IPCC estimates of greenhouse gas nitrous oxide." ScienceDaily. www.sciencedaily.com/releases/2010/12/101220150944.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins