Processes leading to N2O emissions in grassland soil during freezing and thawing

2002 ◽  
Vol 34 (9) ◽  
pp. 1325-1331 ◽  
Author(s):  
Christoph Müller ◽  
M Martin ◽  
R.J Stevens ◽  
R.J Laughlin ◽  
C Kammann ◽  
...  
Keyword(s):  
N2o Emissions ◽  
Freezing And Thawing ◽  
Grassland Soil

N2O emissions and product ratios of nitrification and denitrification as affected by freezing and thawing

2006 ◽  
Vol 38 (12) ◽  
pp. 3411-3420 ◽  
Author(s):  
Pål Tore Mørkved ◽  
Peter Dörsch ◽  
Trond Maukon Henriksen ◽  
Lars Reier Bakken
Keyword(s):  
N2o Emissions ◽  
Freezing And Thawing ◽  
Nitrification And Denitrification

Contribution of nitrification and denitrification to the no and N2O emissions of an acid forest soil, a river sediment and a fertilized grassland soil

1997 ◽  
Vol 29 (11-12) ◽  
pp. 1655-1664 ◽  
Author(s):  
Ronald A. Kester ◽  
Martin E. Meijer ◽  
Jacobus A. Libochant ◽  
Wietse De Boer ◽  
Hendrikus J. Laanbroek
Keyword(s):  
Forest Soil ◽  
River Sediment ◽  
N2o Emissions ◽  
Grassland Soil ◽  
Acid Forest Soil ◽  
Nitrification And Denitrification

scholarly journals Nitrogen oxides emission from two beech forests subjected to different nitrogen loads

2006 ◽  
Vol 3 (3) ◽  
pp. 293-310 ◽  
Author(s):  
B. Kitzler ◽  
S. Zechmeister-Boltenstern ◽  
C. Holtermann ◽  
U. Skiba ◽  
K. Butterbach-Bahl
Keyword(s):  
Nitrogen Oxides ◽  
Co2 Emissions ◽  
Forest Soils ◽  
Time Lag ◽  
N Deposition ◽  
N2o Emissions ◽  
Freezing And Thawing ◽  
Sampling System ◽  
N Input ◽  
No Emissions

Abstract. We analysed nitrogen oxides (N2O, NO) and carbon dioxide (CO2) emissions from two beech forest soils close to Vienna, Austria, which were exposed to different nitrogen input from the atmosphere. The site Schottenwald (SW) received 20.2 kg N ha−1 y−1 and Klausenleopoldsdorf (KL) 12.6 kg N ha−1 y−1 through wet deposition. Nitric oxide emissions from soil were measured hourly with an automatic dynamic chamber system. Daily N2O measurements were carried out by an automatic gas sampling system. Measurements of nitrous oxide (N2O) and CO2 emissions were conducted over larger areas on a biweekly (SW) or monthly (KL) basis by manually operated chambers. We used an autoregression procedure (time-series analysis) for establishing time-lagged relationships between N-oxides emissions and different climate, soil chemistry and N-deposition data. It was found that changes in soil moisture and soil temperature significantly effected CO2 and N-oxides emissions with a time lag of up to two weeks and could explain up to 95% of the temporal variations of gas emissions. Event emissions after rain or during freezing and thawing cycles contributed significantly (for NO 50%) to overall N-oxides emissions. In the two-year period of analysis the annual gaseous N2O emissions at SW ranged from 0.64 to 0.79 kg N ha−1 y−1 and NO emissions were 0.24 to 0.49 kg N ha−1 per vegetation period. In KL significantly lower annual N2O emissions (0.52 to 0.65 kg N2O-N kg ha−1 y−1) as well as considerably lower NO-emissions were observed. During a three-month measurement campaign NO emissions at KL were 0.02 kg N ha−1), whereas in the same time period significantly more NO was emitted in SW (0.32 kg NO-N ha−1). Higher N-oxides emissions, especially NO emissions from the high N-input site (SW) may indicate that atmospheric deposition has an impact on emissions of gaseous N from our forest soils. At KL there was a strong correlation between N-deposition and N-emission over time, which shows that low N-input sites are especially responsive to increasing N-inputs.

Offsetting N2O emissions through nitrifying CO2 fixation in grassland soil

2021 ◽  
pp. 108528
Author(s):  
Weiwei Xia ◽  
Saman Bowatte ◽  
Zhongjun Jia ◽  
Paul Newton
Keyword(s):  
Co2 Fixation ◽  
N2o Emissions ◽  
Grassland Soil

scholarly journals Greenhouse gas fluxes in a drained peatland forest during spring frost-thaw event

2010 ◽  
Vol 7 (5) ◽  
pp. 1715-1727 ◽  
Author(s):  
M. K. Pihlatie ◽  
R. Kiese ◽  
N. Brüggemann ◽  
K. Butterbach-Bahl ◽  
A.-J. Kieloaho ◽  
...  
Keyword(s):  
Peat Soil ◽  
Soil Parameters ◽  
High Time Resolution ◽  
N2o Emissions ◽  
Litter Layer ◽  
Freezing And Thawing ◽  
N2o Production ◽  
Spring Frost ◽  
Top Soil ◽  
Ghg Fluxes

Abstract. Fluxes of greenhouse gases (GHG) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were measured during a two month campaign at a drained peatland forest in Finland by the eddy covariance (EC) technique (CO2 and N2O), and automatic and manual chambers (CO2, CH4 and N2O). In addition, GHG concentrations and soil parameters (mineral nitrogen, temperature, moisture content) in the peat profile were measured. The aim of the measurement campaign was to quantify the GHG fluxes during freezing and thawing of the top-soil, a time period with potentially high GHG fluxes, and to compare different flux measurement methods. The forest was a net CO2 sink during the two months and the fluxes of CO2 dominated the GHG exchange. The peat soil was a small sink of atmospheric CH4 and a small source of N2O. Both CH4 oxidation and N2O production took place in the top-soil whereas CH4 was produced in the deeper layers of the peat, which were unfrozen throughout the measurement period. During the frost-thaw events of the litter layer distinct peaks in CO2 and N2O emissions were observed. The CO2 peak followed tightly the increase in soil temperature, whereas the N2O peak occurred with a delay after the thawing of the litter layer. CH4 fluxes did not respond to the thawing of the peat soil. The CO2 and N2O emission peaks were not captured by the manual chambers and hence we conclude that high time-resolution measurements with automatic chambers or EC are necessary to quantify fluxes during peak emission periods. Sub-canopy EC measurements and chamber-based fluxes of CO2 and N2O were comparable, although the fluxes of N2O measured by EC were close to the detection limit of the system. We conclude that if fluxes are high enough, i.e. greater than 5–10 μg N m−2 h−1, the EC method is a good alternative to measure N2O and CO2 fluxes at ecosystem scale, thereby minimizing problems with chamber enclosures and spatial representativeness of the measurements.

scholarly journals Nitrogen oxides emission from two beech forests subjected to different nitrogen loads

2005 ◽  
Vol 2 (5) ◽  
pp. 1381-1422 ◽  
Author(s):  
B. Kitzler ◽  
S. Zechmeister-Boltenstern ◽  
C. Holtermann ◽  
U. Skiba ◽  
K. Butterbach-Bahl
Keyword(s):  
Nitrogen Oxides ◽  
Co2 Emissions ◽  
Forest Soils ◽  
Time Lag ◽  
N Deposition ◽  
N2o Emissions ◽  
Strong Impact ◽  
Freezing And Thawing ◽  
Sampling System ◽  
N Input

Abstract. We analysed nitrogen oxides (N2O, NO and NO2) and carbon dioxide (CO2) emissions from two beech forest soils close to Vienna, Austria, which were exposed to different nitrogen input from the atmosphere. The site Schottenwald (SW) received 22.6 kg N y-1 and Klausenleopoldsdorf (KL) 13.5 kg N y-1 through wet and dry deposition. Nitrogen oxide emissions from soil were measured hourly with an automatic dynamic chamber system. Daily N2O measurements were carried out by an automatic gas sampling system. Measurements of nitrous oxide (N2O) and CO2 emissions were conducted over larger areas on a biweekly (SW) or monthly (KL) basis by manually operated chambers. We used an autoregression procedure (time-series analysis) for establishing time-lagged relationships between N-oxide emissions and different climate, soil chemistry and N-deposition data. It was found that changes in soil moisture and soil temperature significantly effected CO2 and N-oxide emissions with a time lag of up to two weeks and could explain up to 95% of the temporal variations of gas emissions. Event emissions after rain or during freezing and thawing cycles contributed significantly (for NO 50%) to overall N-oxides emissions. In the two-year period of analysis the annual gaseous N2O losses at SW ranged from 0.65 to 0.77 kg N ha-1 y-1 and NO losses were 0.18 to 0.67 kg N ha-1 per vegetation period. In KL significantly lower annual N2O emissions (0.52 kg N2O-N kg ha-1 y-1) as well as considerably lower NO-losses were observed. During a three-month measurement campaign NO losses at KL were 0.02 kg, whereas in the same time period significantly more NO was emitted in SW (0.32 kg NO-N ha-1). Higher N-oxide emissions, especially NO emissions from the high N-input site (SW) indicate that atmospheric deposition had a strong impact on losses of gaseous N from our forest soils. At KL there was a strong correlation between N-deposition and N-emission over time, which shows that low N-input sites are especially responsive to increasing N-inputs.

Three-Dimensional Structure of Cloned T3 Connector Protein at 1.6nm Resolution

1990 ◽  
Vol 48 (1) ◽  
pp. 282-283
Author(s):  
José L. Carrascosa ◽  
José M. Valpuesta ◽  
Hisao Fujisawa
Keyword(s):  
Dna Sequences ◽  
Expression Vector ◽  
Three Dimensional ◽  
Deae Cellulose ◽  
Dna Packaging ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Freezing And Thawing ◽  
Three Dimensional Structure ◽  
Dimensional Reconstruction

The head to tail connector of bacteriophages plays a fundamental role in the assembly of viral heads and DNA packaging. In spite of the absence of sequence homology, the structure of connectors from different viruses (T4, Ø29, T3, P22, etc) share common morphological features, that are most clearly revealed in their three-dimensional structure. We have studied the three-dimensional reconstruction of the connector protein from phage T3 (gp 8) from tilted view of two dimensional crystals obtained from this protein after cloning and purification.DNA sequences including gene 8 from phage T3 were cloned, into Bam Hl-Eco Rl sites down stream of lambda promotor PL, in the expression vector pNT45 under the control of cI857. E R204 (pNT89) cells were incubated at 42°C for 2h, harvested and resuspended in 20 mM Tris HC1 (pH 7.4), 7mM 2 mercaptoethanol, ImM EDTA. The cells were lysed by freezing and thawing in the presence of lysozyme (lmg/ml) and ligthly sonicated. The low speed supernatant was precipitated by ammonium sulfate (60% saturated) and dissolved in the original buffer to be subjected to gel nitration through Sepharose 6B, followed by phosphocellulose colum (Pll) and DEAE cellulose colum (DE52). Purified gp8 appeared at 0.3M NaCl and formed crystals when its concentration increased above 1.5 mg/ml.

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