Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Illuminating the double face of anthropogenic nitrogen

01.08.2011
Recent studies have shown that human nitrogen additions to terrestrial ecosystems increase the terrestrial carbon dioxide uptake from the atmosphere.

A new study published online this week in Nature Geoscience reports now that the climatic benefits from carbon sequestration are largely offset by increased nitrous oxide emissions, a further side-effect of human nitrogen additions to terrestrial ecosystems.

Human activities have more than doubled nitrogen inputs to the terrestrial biosphere since the 1860s. The two main causes for this are increased atmospheric nitrogen deposition from, for instance, fossil fuel burning, and the application of fertilizers in agriculture.

Nitrogen is an essential nutrient for plant and microbial growth, and one of the key limiting nutrients in many natural ecosystems. The anthropogenic perturbations of the nitrogen cycle are known to affect the terrestrial sources and sinks of greenhouse gases such as carbon dioxide (CO2) and nitrous oxide (N2O). These changes are potentially very important as they may significantly affect the climate system, but their magnitude is still unknown.

“When added to nitrogen-limited ecosystems, it [nitrogen] can stimulate plant growth and/or suppress soil respiration, thereby leading to increased ecosystem carbon storage” explains Sönke Zaehle. However, there are also potentially negative consequences for adding nitrogen to ecosystems, as increasing nitrogen availability may enhance nitrogen losses from ecosystems, and eventually even have damaging effects on plant health. Particularly relevant for climate are elevated emissions of ni-trous oxide, a long-lived greenhouse gas that is emitted from fertilised fields, as well as nitrogen-rich forest and grassland ecosystems.

Drawing on reconstructions of past and present anthropogenic nitrogen deposition and fertiliser applications, Sönke Zaehle and colleagues used a global computer model of the coupled terrestrial carbon and nitrogen cycles to better understand the consequences of this anthropogenic nitrogen perturbation for the climate system. Their results confirm that the anthropogenic nitrogen perturbation has profoundly affected terrestrial carbon dioxide and nitrous oxide fluxes. Human nitrogen additions are the principle cause for the increase in terrestrial nitrous oxide emission since 1960, and contribute to about one fifth of the current global net carbon uptake (1996-2005).

Sönke Zaehle and colleagues then determined the effect of anthropogenic nitrogen on the at-mospheric concentrations of the greenhouse gases CO2 and N2O, and assessed the resulting consequences for present-day climate. The key finding is that the climatic effects of the anthropogenic nitrogen perturbation from both gases are very substantial but of opposite signs. The cooling effect due to enhanced carbon uptake of the terrestrial biosphere is more than compensated for by the warming effects from enhanced terrestrial N2O emissions.

However, “the fact that in our study the N2O effect appears stronger than the CO2 effect should not be over-interpreted” cautions Zaehle. Rather, the study highlights the relevance of anthropogenic nitrogen in the climate system and the need to consider the effects of carbon and nitrogen cycling jointly. “I hope that this study fosters further research to better understand the effects of human N on ecosystem dynamics through joint observational and modelling studies”, Zaehle adds.
Original data are published in:
S. Zaehle, P. Ciais, A. D. Friend, V. Prieur (2011): Carbon benefits of anthropogenic reactive nitrogen offset by nitrous oxide emissions, Nature Geoscience, Vol 4, August 2011, doi 10.1038/NGEO1207
Contact:
Sönke Zaehle
Max Planck Institute for Biogeochemistry, Jena, Germany
Phone: +49 3641 57 63 25
Fax: +49 3641 57 73 00
Email: soenke.zaehle@bgc-jena.mpg.de
Philippe Ciais
Laboratoire des Sciences du Climat et de L’Environnement, Gif/Yvette, France
Email : philippe.ciais@cea.fr
Andrew D. Friend
University of Cambridge, Cambridge, UK
Email: Andrew.Friend@geog.cam.ac.uk
Vincent Prieur
Laboratoire des Sciences du Climat et de l’Environnement, Gif/Yvette, France
Email : vprieur@lsce.ipsl.fr

Susanne Hermsmeier | Max-Planck-Institut
Further information:
http://www.bgc-jena.mpg.de/

More articles from Earth Sciences:

nachricht 'Quartz' crystals at the Earth's core power its magnetic field
23.02.2017 | Tokyo Institute of Technology

nachricht NASA spies Tropical Cyclone 08P's formation
23.02.2017 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>