Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Global rivers emit 3 times IPCC estimates of greenhouse gas nitrous oxide

21.12.2010
Waterways receiving nitrogen from human activities are significant source

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.

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.

Cheryl Dybas | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Earth Sciences:

nachricht More than 100 years of flooding and erosion in 1 event
28.03.2017 | Geological Society of America

nachricht Satellites reveal bird habitat loss in California
28.03.2017 | Duke University

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>