Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Increasing nitrogen in Earth’s soils may signal global changes, say U. of Colorado researchers

31.10.2002


The rapid increase of nitrogen falling from the sky as a result of fossil-fuel combustion and crop fertilization, combined with carbon stored in Earth’s soils, could change the rate of the greenhouse gas, carbon dioxide, rising into the atmosphere, according to a new study.



Scientists believe about 300 times more carbon is stored in soils than is being put in the atmosphere in the form of C02, according to biology Assistant Professor Alan Townsend of the University of Colorado at Boulder. Each year soils release about 20 times more carbon than industrial activities through decomposition.

"Decomposition is primarily balanced by plant growth, but increasing nitrogen falling on ecosystems could change that balance," he said. The study shows tundra soils are unexpectedly sensitive to added nitrogen, bringing up the question of how increases in nitrogen throughout the world might affect C02 storage areas, or ’sinks,’ on land," Townsend said.


A paper on the subject by Townsend, co-principal author Jason Neff of the U.S. Geological Survey in Denver, Scott Lehman, Joyce Turnbull and William Bowman from CU-Boulder and Gerd Gleixner from Germany’s Max Planck Institute will appear in the Oct. 31 issue of Nature.

C02 in the atmosphere is believed to have risen by about one-third since the Industrial Revolution began in roughly 1760, contributing to a warming climate.

"The nitrogen deposited on land might act like fertilizer and cause plants to grow more, at least for a while, which would suck up some carbon from the atmosphere," said Townsend, an associate at CU-Boulder’s Arctic and Alpine Research Institute, along with co-authors Lehman, Turnbull and Bowman. "But it also could cause soils to lose some of their carbon, which would add even more C02 to the atmosphere."

The study area was Niwot Ridge 35 miles west of Boulder, administered by INSTAAR and one of 20 Long-Term Ecological Sites in North America funded by the National Science Foundation. The big surprise is that many scientists believed soils would not respond so significantly to changes in nitrogen, he said.

"One of our big concerns now is that we know the world’s soils have at least three times more carbon than plants, and that increasing the nitrogen hitting these soils could change the size of that huge pool," he said. Since the pool is so large, even a small change could have a big effect on the atmosphere, and therefore future climate."

Scientists have documented increases in how much C02 is being produced by human activity, and concluded that only about half of that amount is reaching the atmosphere, said Townsend. So the carbon sinks on Earth taking up and storing the carbon molecules in the world’s vegetation, soils and oceans must be immense, he said.

"If these sinks slow down or turn off in the near future, we could see much larger increases in atmospheric C02," said Townsend. "If cold tundra soils are sensitive to nitrogen, it raises concerns about what might be happening in other, warmer parts of the world where things can change more rapidly," he said.

"Niwot Ridge is by no means unique," said Townsend. "Nitrogen deposition is going up all over the world, especially throughout the United States, Europe and much of Asia." In the eastern United States, for example, scientists are seeing as much as 10 times more nitrogen flowing into the rivers compared to just a few decades ago.

"I think the problems we are seeing from the altered nitrogen cycle are worse than what we are seeing in climate change around the world, at least for now," he said. "In the history of the Earth, half the nitrogen fertilizer ever used has been applied since 1990. A lot of this nitrogen does not go where it is supposed to, causing a cascade of environmental problems that are worsening at an alarming rate."

Although rivers like the Mississippi have many times the amount of nitrogen than they contained 30 years ago, there are "tractable solutions" to the problem, he said.

"Agricultural extension services often recommend more nitrogen than is needed for fertilization, and some farmers tend to put on even more nitrogen."

Trying to calculate the nitrogen turnover rate of carbon in soils is difficult, he said. "In a lot of the world, far more fertilizer is used than is needed to maximize crop growth, and it is this extra use that causes a lot of the problems. In many cases, farmers could make small changes in how much fertilizer they use, or when they use it, but make a big difference in how much nitrogen leaks off their fields."

It is far too soon to say if more nitrogen in the world’s soils will mean more or less C02 in the atmosphere, Neff said. "Soils contain a huge mix of different types of carbon, and it likely does all respond the same to changing nitrogen. But that is what we saw at Niwot Ridge, and the same probably is true elsewhere."

Alan Townsend | EurekAlert!
Further information:
http://www.colorado.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>