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Ludwig, Jörg; Meixner, Franz X.; Vogel, Bernhard; Förstner, Jochen

doi:10.1023/a:1006424330555

Cited by 259 publications

(79 citation statements)

References 87 publications

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“…Most of the NO x emitted through the snowpack at NWT was in the form of NO, making it possible to compare our winter fluxes of NO x with these published data. NWT NO x flux is roughly comparable to the values reported by Ludwig et al (2001) for the snow-free season of tundra and subalpine ecosystems, thus confirming that alpine and subalpine snow-covered soils are comparatively weak sources of NO x , but also suggesting that winter production could be as high as the snow-free season production in this ecosystem.…”

Section: Comparison With Other Ecosystemssupporting

confidence: 81%

“…Two previous measurements of NO x flux from snow-covered soils allow comparison with our data (Maggiotto and Wagner-Riddle 2001;Ludwig et al 2001). Compared to these reports, NWT NO x subnivean production is about two-orders of magnitude lower.…”

Section: Comparison With Other Ecosystemssupporting

confidence: 67%

“…Compared to these reports, NWT NO x subnivean production is about two-orders of magnitude lower. Moreover, Ludwig et al (2001) reviewed the current literature on NO emissions from soils, with only two of over 200 studies from tundra and subalpine ecosystems. Most of the NO x emitted through the snowpack at NWT was in the form of NO, making it possible to compare our winter fluxes of NO x with these published data.…”

Section: Comparison With Other Ecosystemsmentioning

confidence: 99%

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Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

et al. 2009

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The soil emission rates (fluxes) of nitrous oxide (N 2 O) and nitrogen oxides (NO ? NO 2 = NO x ) through a seasonal snowpack were determined by a flux gradient method from near-continuous 2-year measurements using an automated system for sampling interstitial air at various heights within the snowpack from a subalpine site at Niwot Ridge, . During spring N 2 O emissions first peaked and then dropped sharply as the soil water content increased from the release of snowpack meltwater, while other gases, including NO x and CO 2 did not show this behavior. To compare and contrast the winter fluxes with snow-free conditions, N 2 O fluxes were also measured at the same site in the summers of 2006 and 2007 using a closed soil chamber method. Summer N 2 O fluxes followed a decreasing trend during the dry-out period after snowmelt, interrupted by higher values related to precipitation events. These peaks were up to 2-3 times higher than the background summer levels. The integrated N 2 O-N loss over the summer period was calculated to be 1.1-2.4 kg N ha -1 , compared to *0.24-0.34 kg N ha -1 for the winter season. These wintertime N 2 O fluxes from subniveal soil are generally higher than the few previously published data. These results are of the same order of magnitude as data from more productive ecosystems such as fertilized grasslands and high-N-cycling forests, most likely because of a combination of the relatively welldeveloped soils and the fact that subnivean biogeochemical processes are promoted by the deep, insulating snowpack. Hence, microbially mediated oxidized nitrogen emissions occurring during the winter can be a significant part of the N-cycle in seasonally snow-covered subalpine ecosystems.

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Section: Comparison With Other Ecosystemssupporting

confidence: 81%

Section: Comparison With Other Ecosystemssupporting

confidence: 67%

Section: Comparison With Other Ecosystemsmentioning

confidence: 99%

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Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

et al. 2009

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“…Soil incubation studies in the laboratory have the advantage to allow for measuring N-trace gas emissions from a high number of samples, thereby allowing to covering regional variability of soils. Several previous studies reported N-trace gas fluxes, which were derived from soil incubation experiments and which agreed well with field-derived fluxes determined via chambers (Gut et al, 1999;Otter et al, 1999;Ludwig et al, 2001.…”

Section: Introductionsupporting

confidence: 81%

Spatial variations of nitrogen trace gas emissions from tropical mountain forests in Nyungwe, Rwanda

Gharahi

Werner²,

Ntaboba³

et al. 2012

Biogeosciences

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Abstract. Globally, tropical forest soils represent the second largest source of N 2 O and NO. However, there is still considerable uncertainty on the spatial variability and soil properties controlling N trace gas emission. Therefore, we carried out an incubation experiment with soils from 31 locations in the Nyungwe tropical mountain forest in southwestern Rwanda. All soils were incubated at three different moisture levels (50, 70 and 90 % water filled pore space (WFPS)) at 17 • C. Nitrous oxide emission varied between 4.5 and 400 µg N m −2 h −1 , while NO emission varied from 6.6 to 265 µg N m −2 h −1 . Mean N 2 O emission at different moisture levels was 46.5 ± 11.1 (50 %WFPS), 71.7 ± 11.5 (70 %WFPS) and 98.8 ± 16.4 (90 %WFPS) µg N m −2 h −1 , while mean NO emission was 69.3 ± 9.3 (50 %WFPS), 47.1 ± 5.8 (70 %WFPS) and 36.1 ± 4.2 (90 %WFPS) µg N m −2 h −1 . The latter suggests that climate (i.e. dry vs. wet season) controls N 2 O and NO emissions. Positive correlations with soil carbon and nitrogen indicate a biological control over N 2 O and NO production. But interestingly N 2 O and NO emissions also showed a positive correlation with free iron and a negative correlation with soil pH (only N 2 O). The latter suggest that chemodenitrification might, at least for N 2 O, be an important production pathway. In conclusion improved understanding and process based modeling of N trace gas emission from tropical forests will benefit from spatially explicit trace gas emission estimates linked to basic soil property data and differentiating between biological and chemical pathways for N trace gas formation.

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“…The expected impacts of global change on the soil-level source strength for NH 3 , NO and N 2 O are described in detail elsewhere in this review (Sect. 4.1.1) and, in the case of NO, have been reviewed by Pilegaard (2013) and by Ludwig et al (2001). For agricultural soils the changes are essentially controlled by agricultural management and cropping practices (especially fertilizer inputs: form, quantity, technique and timing of application), and by changes in climate that affect soil temperature and moisture, impacting on the turnover of soil organic matter (heterotrophic respiration), fertilizer infiltration, NH 3 volatilization and the rates of nitrification and denitrification (Butterbach-Bahl and Dannenmann, 2011;Sutton et al, 2013b;Flechard et al, 2013).…”

Section: Soil Surface Exchangementioning

confidence: 99%

Effects of global change during the 21st century on the nitrogen cycle

et al. 2015

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Abstract. The global nitrogen (N) cycle at the beginning of the 21st century has been shown to be strongly influenced by the inputs of reactive nitrogen (N r ) from human activities, including combustion-related NO x , industrial and agricultural N fixation, estimated to be 220 Tg N yr −1 in 2010, which is approximately equal to the sum of biological N fixation in unmanaged terrestrial and marine ecosystems. According to current projections, changes in climate and land use during the 21st century will increase both biological and anthropogenic fixation, bringing the total to approximately 600 Tg N yr −1 by around 2100. The fraction contributed directly by human activities is unlikely to increase substantially if increases in nitrogen use efficiency in agriculture are achieved and control measures on combustion-related emissions implemented.Some N-cycling processes emerge as particularly sensitive to climate change. One of the largest responses to climate in the processing of N r is the emission to the atmosphere of NH 3 , which is estimated to increase from 65 Tg N yr −1 in 2008 to 93 Tg N yr −1 in 2100 assuming a change in global surface temperature of 5 • C in the absence of increased anthropogenic activity. With changes in emissions in response to increased demand for animal products the combined effect would be to increase NH 3 emissions to 135 Tg N yr −1 . Another major change is the effect of climate changes on aerosol composition and specifically the increased sublimation of NH 4 NO 3 close to the ground to form HNO 3 and NH 3 in a warmer climate, which deposit more rapidly to terrestrial surfaces than aerosols. Inorganic aerosols over the polluted regions especially in Europe and North America were dominated by (NH 4 ) 2 SO 4 in the 1970s to 1980s, and large reductions in emissions of SO 2 have removed most of the SO 2− 4 from the atmosphere in these regions. Inorganic aerosols from anthropogenic emissions are now dominated by NH 4 NO 3 , a volatile aerosol which contributes substantially to PM 10 and human health effects globally as well as eutrophication and climate effects. The volatility of NH 4 NO 3 and rapid dry deposition of the vapour phase dissociation Published by Copernicus Publications on behalf of the European Geosciences Union. D. Fowler et al.: Effects of global change during the 21st century on the nitrogen cycleproducts, HNO 3 and NH 3 , is estimated to be reducing the transport distances, deposition footprints and inter-country exchange of N r in these regions.There have been important policy initiatives on components of the global N cycle. These have been regional or country-based and have delivered substantial reductions of inputs of N r to sensitive soils, waters and the atmosphere. To date there have been no attempts to develop a global strategy to regulate human inputs to the nitrogen cycle. However, considering the magnitude of global N r use, potential future increases, and the very large leakage of N r in many forms to soils, waters and the atmosphere, international action is re...

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Cited by 259 publications

References 87 publications

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

Winter and summer nitrous oxide and nitrogen oxides fluxes from a seasonally snow-covered subalpine meadow at Niwot Ridge, Colorado

Spatial variations of nitrogen trace gas emissions from tropical mountain forests in Nyungwe, Rwanda

Effects of global change during the 21st century on the nitrogen cycle

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