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Sample records for ammonia nitrous oxides

  1. Production of oceanic nitrous oxide by ammonia-oxidizing archaea

    Directory of Open Access Journals (Sweden)

    C. R. Löscher

    2012-07-01

    Full Text Available The recent finding that microbial ammonia oxidation in the ocean is performed by archaea to a greater extent than by bacteria has drastically changed the view on oceanic nitrification. The numerical dominance of archaeal ammonia-oxidizers (AOA over their bacterial counterparts (AOB in large parts of the ocean leads to the hypothesis that AOA rather than AOB could be the key organisms for the oceanic production of the strong greenhouse gas nitrous oxide (N2O that occurs as a by-product of nitrification. Very recently, enrichment cultures of marine ammonia-oxidizing archaea have been reported to produce N2O.

    Here, we demonstrate that archaeal ammonia monooxygenase genes (amoA were detectable throughout the water column of the eastern tropical North Atlantic (ETNA and eastern tropical South Pacific (ETSP Oceans. Particularly in the ETNA, comparable patterns of abundance and expression of archaeal amoA genes and N2O co-occurred in the oxygen minimum, whereas the abundances of bacterial amoA genes were negligible. Moreover, selective inhibition of archaea in seawater incubations from the ETNA decreased the N2O production significantly. In studies with the only cultivated marine archaeal ammonia-oxidizer Nitrosopumilus maritimus SCM1, we provide the first direct evidence for N2O production in a pure culture of AOA, excluding the involvement of other microorganisms as possibly present in enrichments. N. maritimus showed high N2O production rates under low oxygen concentrations comparable to concentrations existing in the oxycline of the ETNA, whereas the N2O production from two AOB cultures was comparably low under similar conditions. Based on our findings, we hypothesize that the production of N2O in tropical ocean areas results mainly from archaeal nitrification and will be affected by the predicted decrease in dissolved

  2. SOIL NITROUS OXIDE, NITRIC OXIDE, AND AMMONIA EMISSIONS FROM A RECOVERING RIPARIAN ECOSYSTEM IN SOUTHERN APPALACHIA

    Science.gov (United States)

    The paper presents two years of seasonal nitric oxide, ammonia, and nitrous oxide trace gas fluxes measured in a recovering riparian zone with cattle excluded and in an adjacent riparian zone grazed by cattle. In the recovering riparian zone, average nitric oxide, ammonia, and ni...

  3. AMMONIA REMOVAL AND NITROUS OXIDE PRODUCTION IN GAS-PHASE COMPOST BIOFILTERS

    Science.gov (United States)

    Biofiltration technology is widely utilized for treating ammonia gas (NH3), with one of its potential detrimental by-products being nitrous oxide (N2O), a greenhouse gas approximately 300 times more reactive to infrared than CO2. The present work intends to provide the relation between NH3 removal d...

  4. Biochar type and factors affecting N transformation, ammonia volatilization, and nitrous oxide emissions

    Science.gov (United States)

    Soil amendment with biochar has shown the potential to improve nitrogen (N) availability for plant uptake and reduce environmental losses via ammonia (NH3) and nitrous oxide (N2O) emissions. There are still many unknowns on how biochar type and soil conditions affect N dynamics and processes associa...

  5. Continuous measurements of ammonia, nitrous oxide and methane from air scrubbers at pig housing facilities.

    Science.gov (United States)

    Van der Heyden, C; Brusselman, E; Volcke, E I P; Demeyer, P

    2016-10-01

    Ammonia, largely emitted by agriculture, involves a great risk for eutrophication and acidification leading to biodiversity loss. Air scrubbers are widely applied to reduce ammonia emission from pig and poultry housing facilities, but it is not always clear whether their performance meets the requirements. Besides, there is a growing international concern for the livestock related greenhouse gases methane and nitrous oxide but hardly any data concerning their fate in air scrubbers are available. This contribution presents the results from measurement campaigns conducted at a chemical, a biological and a two-stage biological air scrubber installed at pig housing facilities in Flanders. Ammonia, nitrous oxide and methane at the inlet and outlet of the air scrubbers were monitored on-line during one week using a photoacoustic gas monitor, which allowed to investigate diurnal fluctuations in the removal performance of air scrubbers. Additionally, the homogeneity of the air scrubbers, normally checked by gas detection tubes, was investigated in more detail using the continuous data. The biological air scrubber with extra nitrification tank performed well in terms of ammonia removal (86 ± 6%), while the two-stage air scrubber suffered from nitrifying bacteria inhibition. In the chemical air scrubber the pH was not kept constant, lowering the ammonia removal efficiency. A lower ammonia removal efficiency was found during the day, when the ventilation rate was the highest. Nitrous oxide was produced inside the biological and two-stage scrubber, resulting in an increased outlet concentration of more than 200%. Methane could not be removed in the different air scrubbers because of its low water solubility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Ammonia and nitrous oxide interactions - importance of organic matter management

    DEFF Research Database (Denmark)

    Petersen, Søren O; Sommer, Sven G.

    Intensification of livestock production in many parts of the world has led to increasing atmospheric losses of N in connection with storage and field application of manure. Both types of emissions are influenced by manure organic matter content via mechanisms such as composting, crust formation......, mineralization–immobilization turnover, and water retention. Manure management affects the potential for, and balance between, NH3 and N2O emissions. The interaction between NH3 and N2O may be positive (e.g., both emissions are reduced by an airtight cover during storage and stimulated by composting......), or negative (e.g., direct N2O emissions from soil will potentially increase if losses of NH3 are prevented during storage or field application). Emissions of NH3 and N2O negatively affect N use efficiency and the greenhouse gas (GHG) balance of livestock production. Ammonia and N2O emissions and GHG balances...

  7. Aerobic nitrous oxide production through N-nitrosating hybrid formation in ammonia-oxidizing archaea.

    Science.gov (United States)

    Stieglmeier, Michaela; Mooshammer, Maria; Kitzler, Barbara; Wanek, Wolfgang; Zechmeister-Boltenstern, Sophie; Richter, Andreas; Schleper, Christa

    2014-05-01

    Soil emissions are largely responsible for the increase of the potent greenhouse gas nitrous oxide (N2O) in the atmosphere and are generally attributed to the activity of nitrifying and denitrifying bacteria. However, the contribution of the recently discovered ammonia-oxidizing archaea (AOA) to N2O production from soil is unclear as is the mechanism by which they produce it. Here we investigate the potential of Nitrososphaera viennensis, the first pure culture of AOA from soil, to produce N2O and compare its activity with that of a marine AOA and an ammonia-oxidizing bacterium (AOB) from soil. N. viennensis produced N2O at a maximum yield of 0.09% N2O per molecule of nitrite under oxic growth conditions. N2O production rates of 4.6±0.6 amol N2O cell(-1) h(-1) and nitrification rates of 2.6±0.5 fmol NO2(-) cell(-1) h(-1) were in the same range as those of the AOB Nitrosospira multiformis and the marine AOA Nitrosopumilus maritimus grown under comparable conditions. In contrast to AOB, however, N2O production of the two archaeal strains did not increase when the oxygen concentration was reduced, suggesting that they are not capable of denitrification. In (15)N-labeling experiments we provide evidence that both ammonium and nitrite contribute equally via hybrid N2O formation to the N2O produced by N. viennensis under all conditions tested. Our results suggest that archaea may contribute to N2O production in terrestrial ecosystems, however, they are not capable of nitrifier-denitrification and thus do not produce increasing amounts of the greenhouse gas when oxygen becomes limiting.

  8. Ammonia, nitrous oxide and hydrogen cyanide emissions from five passenger vehicles

    International Nuclear Information System (INIS)

    Karlsson, Hua Lu

    2004-01-01

    In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH 3 ), nitrous oxide (N 2 O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH 3 , N 2 O and HCN emissions are low

  9. Ammonia, nitrous oxide and hydrogen cyanide emissions from five passenger vehicles.

    Science.gov (United States)

    Karlsson, Hua Lu

    2004-12-01

    In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH(3)), nitrous oxide (N(2)O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH(3), N(2)O and HCN emissions are low.

  10. Emissions of ammonia, nitrous oxide and methane during composting of organic household waste

    International Nuclear Information System (INIS)

    Gunnarsdotter Beck-Friis, Barbro

    2001-01-01

    In Sweden, composting of source-separated organic household waste is increasing, both domestically at the small-scale, and in larger municipal plants. Composting means a microbial decomposition of organic material, which results in the production of environmentally undesirable gases, such as ammonia (NH 3 ), nitrous oxide (N 2 O) and methane (CH 4 ). The aim of this thesis was to study the emissions of NH 3 , N 2 O and CH 4 to the atmosphere during composting of source-separated organic household waste. The studies were conducted in an experimental reactor under constant and controlled conditions and in municipal compost heaps. Emissions of NH 3 , N 2 O and CH 4 occurred at different phases during composting. Ammonia started to volatilise during the shift from mesophilic to thermophilic conditions when short-chained fatty acids were decomposed. Nitrous oxide was only emitted during the first days of composting and later during the cooling phase when nitrate was formed. Methane was only produced during the thermophilic phase. Large municipal compost heaps are a significant source for the production and emission of the greenhouse gases N 2 O and CH 4 . To avoid unwanted gaseous emissions to the atmosphere during composting, gaseous exchange with the atmosphere should be controlled in future composting plants

  11. Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems.

    Science.gov (United States)

    Chandran, Kartik; Stein, Lisa Y; Klotz, Martin G; van Loosdrecht, Mark C M

    2011-12-01

    Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO₂⁻) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N₂O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O₂) is associated with N₂O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N₂O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N₂O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N₂O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N₂O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

  12. Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium

    Directory of Open Access Journals (Sweden)

    C. H. Frame

    2010-09-01

    Full Text Available Nitrous oxide (N2O is a trace gas that contributes to the greenhouse effect and stratospheric ozone depletion. The N2O yield from nitrification (moles N2O-N produced per mole ammonium-N consumed has been used to estimate marine N2O production rates from measured nitrification rates and global estimates of oceanic export production. However, the N2O yield from nitrification is not constant. Previous culture-based measurements indicate that N2O yield increases as oxygen (O2 concentration decreases and as nitrite (NO2 concentration increases. Here, we have measured yields of N2O from cultures of the marine β-proteobacterium Nitrosomonas marina C-113a as they grew on low-ammonium (50 μM media. These yields, which were typically between 4 × 10−4 and 7 × 10−4 for cultures with cell densities between 2 × 102 and 2.1 × 104 cells ml−1, were lower than previous reports for ammonia-oxidizing bacteria. The observed impact of O2 concentration on yield was also smaller than previously reported under all conditions except at high starting cell densities (1.5 × 106 cells ml−1, where 160-fold higher yields were observed at 0.5% O2 (5.1 μM dissolved O2 compared with 20% O2 (203 μM dissolved O2. At lower cell densities (2 × 102 and 2.1 × 104 cells ml−1, cultures grown under 0.5% O2 had yields that were only 1.25- to 1.73-fold higher than cultures grown under 20% O2. Thus, previously reported many-fold increases in N2O yield with dropping O2 could be reproduced only at cell densities that far exceeded those of ammonia oxidizers in the ocean. The presence of excess NO2 (up to 1 mM in the growth

  13. Nitrous oxide emission from the agriculture in the Netherlands. Outline of effects of manure and ammonia measures

    International Nuclear Information System (INIS)

    Kros, J.; De Vries, W.; Oenema, O.; Velthof, G.; Kuikman, P.J.; Van Hove, B.

    2004-01-01

    By means of the model INITIATOR an integral outline was made of the effects of several measures within the framework of the manure and ammonia policy focusing on nitrous oxide emission. The results are compared with the IPCC method. The model INITIATOR is a mechanistic model by means of which the carbon cycle in the Netherlands can be differentiated on a regional scale as a function of land use, type of soil and hydrology [nl

  14. Mechanisms of Persistence of the Ammonia-Oxidizing Bacteria Nitrosomonas to the Biocide Free Nitrous Acid.

    Science.gov (United States)

    Laloo, Andrew E; Wei, Justin; Wang, Dongbo; Narayanasamy, Shaman; Vanwonterghem, Inka; Waite, David; Steen, Jason; Kaysen, Anne; Heintz-Buschart, Anna; Wang, Qilin; Schulz, Benjamin; Nouwens, Amanda; Wilmes, Paul; Hugenholtz, Philip; Yuan, Zhiguo; Bond, Philip L

    2018-05-01

    Free nitrous acid (FNA) exerts a broad range of antimicrobial effects on bacteria, although susceptibility varies considerably among microorganisms. Among nitrifiers found in activated sludge of wastewater treatment processes (WWTPs), nitrite-oxidizing bacteria (NOB) are more susceptible to FNA compared to ammonia-oxidizing bacteria (AOB). This selective inhibition of NOB over AOB in WWTPs bypasses nitrate production and improves the efficiency and costs of the nitrogen removal process in both the activated sludge and anaerobic ammonium oxidation (Anammox) system. However, the molecular mechanisms governing this atypical tolerance of AOB to FNA have yet to be understood. Herein we investigate the varying effects of the antimicrobial FNA on activated sludge containing AOB and NOB using an integrated metagenomics and label-free quantitative sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) metaproteomic approach. The Nitrosomonas genus of AOB, on exposure to FNA, maintains internal homeostasis by upregulating a number of known oxidative stress enzymes, such as pteridine reductase and dihydrolipoyl dehydrogenase. Denitrifying enzymes were upregulated on exposure to FNA, suggesting the detoxification of nitrite to nitric oxide. Interestingly, proteins involved in stress response mechanisms, such as DNA and protein repair enzymes, phage prevention proteins, and iron transport proteins, were upregulated on exposure to FNA. In addition enzymes involved in energy generation were also upregulated on exposure to FNA. The total proteins specifically derived from the NOB genus Nitrobacter was low and, as such, did not allow for the elucidation of the response mechanism to FNA exposure. These findings give us an understanding of the adaptive mechanisms of tolerance within the AOB Nitrosomonas to the biocidal agent FNA.

  15. Modeling of nitrous oxide production by autotrophic ammonia-oxidizing bacteria with multiple production pathways.

    Science.gov (United States)

    Ni, Bing-Jie; Peng, Lai; Law, Yingyu; Guo, Jianhua; Yuan, Zhiguo

    2014-04-01

    Autotrophic ammonia oxidizing bacteria (AOB) have been recognized as a major contributor to N2O production in wastewater treatment systems. However, so far N2O models have been proposed based on a single N2O production pathway by AOB, and there is still a lack of effective approach for the integration of these models. In this work, an integrated mathematical model that considers multiple production pathways is developed to describe N2O production by AOB. The pathways considered include the nitrifier denitrification pathway (N2O as the final product of AOB denitrification with NO2(-) as the terminal electron acceptor) and the hydroxylamine (NH2OH) pathway (N2O as a byproduct of incomplete oxidation of NH2OH to NO2(-)). In this model, the oxidation and reduction processes are modeled separately, with intracellular electron carriers introduced to link the two types of processes. The model is calibrated and validated using experimental data obtained with two independent nitrifying cultures. The model satisfactorily describes the N2O data from both systems. The model also predicts shifts of the dominating pathway at various dissolved oxygen (DO) and nitrite levels, consistent with previous hypotheses. This unified model is expected to enhance our ability to predict N2O production by AOB in wastewater treatment systems under varying operational conditions.

  16. Effects of lignite application on ammonia and nitrous oxide emissions from cattle pens

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jianlei, E-mail: su@unimelb.edu.au [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Bai, Mei [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Shen, Jianlin [Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Griffith, David W.T. [Department of Chemistry, University of Wollongong, NSW 2522 (Australia); Denmead, Owen T. [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Hill, Julian [Ternes Agricultural Consulting Pty Ltd, Upwey, VIC 3158 (Australia); Lam, Shu Kee; Mosier, Arvin R. [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia); Chen, Deli, E-mail: delichen@unimelb.edu.au [Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, VIC 3010 (Australia)

    2016-09-15

    Beef cattle feedlots are a major source of ammonia (NH{sub 3}) emissions from livestock industries. We investigated the effects of lignite surface applications on NH{sub 3} and nitrous oxide (N{sub 2}O) emissions from beef cattle feedlot pens. Two rates of lignite, 3 and 6 kg m{sup −2}, were tested in the treatment pen. No lignite was applied in the control pen. Twenty-four Black Angus steers were fed identical commercial rations in each pen. We measured NH{sub 3} and N{sub 2}O concentrations continuously from 4th Sep to 13th Nov 2014 using Quantum Cascade Laser (QCL) NH{sub 3} analysers and a closed-path Fourier Transform Infrared Spectroscopy analyser (CP-FTIR) in conjunction with the integrated horizontal flux method to calculate NH{sub 3} and N{sub 2}O fluxes. During the feeding period, 16 and 26% of the excreted nitrogen (N) (240 g N head{sup −1} day{sup −1}) was lost via NH{sub 3} volatilization from the control pen, while lignite application decreased NH{sub 3} volatilization to 12 and 18% of the excreted N, for Phase 1 and Phase 2, respectively. Compared to the control pen, lignite application decreased NH{sub 3} emissions by approximately 30%. Nitrous oxide emissions from the cattle pens were small, 0.10 and 0.14 g N{sub 2}O-N head{sup −1} day{sup −1} (< 0.1% of excreted N) for the control pen, for Phase 1 and Phase 2, respectively. Lignite application increased direct N{sub 2}O emissions by 40 and 57%, to 0.14 and 0.22 g N{sub 2}O-N head{sup −1} day{sup −1}, for Phase 1 and Phase 2, respectively. The increase in N{sub 2}O emissions resulting from lignite application was counteracted by the lower indirect N{sub 2}O emission due to decreased NH{sub 3} volatilization. Using 1% as a default emission factor of deposited NH{sub 3} for indirect N{sub 2}O emissions, the application of lignite decreased total N{sub 2}O emissions. - Graphical abstract: Lignite application substantially decreased NH{sub 3} emissions from cattle feedlots and increased

  17. Evaluating four mathematical models for nitrous oxide production by autotrophic ammonia-oxidizing bacteria.

    Science.gov (United States)

    Ni, Bing-Jie; Yuan, Zhiguo; Chandran, Kartik; Vanrolleghem, Peter A; Murthy, Sudhir

    2013-01-01

    There is increasing evidence showing that ammonia-oxidizing bacteria (AOB) are major contributors to N(2)O emissions from wastewater treatment plants (WWTPs). Although the fundamental metabolic pathways for N(2)O production by AOB are now coming to light, the mechanisms responsible for N(2)O production by AOB in WWTP are not fully understood. Mathematical modeling provides a means for testing hypotheses related to mechanisms and triggers for N(2)O emissions in WWTP, and can then also become a tool to support the development of mitigation strategies. This study examined the ability of four mathematical model structures to describe two distinct mechanisms of N(2)O production by AOB. The production mechanisms evaluated are (1) N(2)O as the final product of nitrifier denitrification with NO(2)- as the terminal electron acceptor and (2) N(2)O as a byproduct of incomplete oxidation of hydroxylamine (NH(2)OH) to NO(2)-. The four models were compared based on their ability to predict N(2)O dynamics observed in three mixed culture studies. Short-term batch experimental data were employed to examine model assumptions related to the effects of (1) NH4+ concentration variations, (2) dissolved oxygen (DO) variations, (3) NO(2)- accumulations and (4) NH(2OH as an externally provided substrate. The modeling results demonstrate that all these models can generally describe the NH4+, NO(2)-, and NO(3)- data. However, none of these models were able to reproduce all measured N(2)O data. The results suggest that both the denitrification and NH(2)OH pathways may be involved in N(2)O production and could be kinetically linked by a competition for intracellular reducing equivalents. A unified model capturing both mechanisms and their potential interactions needs to be developed with consideration of physiological complexity. Copyright © 2012 Wiley Periodicals, Inc.

  18. Impact of dicyandiamide on emissions of nitrous oxide, nitric oxide and ammonia from agricultural field in the North China Plain.

    Science.gov (United States)

    Zhou, Yizhen; Zhang, Yuanyuan; Tian, Di; Mu, Yujing

    2016-02-01

    Nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3) emissions from an agricultural field in the North China Plain were compared for three treatments during a whole maize growing period from 26 June to 11 October, 2012. Compared with the control treatment (without fertilization, designated as CK), remarkable pulse emissions of N2O, NO and NH3 were observed from the normal fertilization treatment (designated as NP) just after fertilization, whereas only N2O and NH3 pulse emissions were evident from the nitrification inhibitor treatment (designated as ND). The reduction proportions of N2O and NO emissions from the ND treatment compared to those from the NP treatment during the whole maize growing period were 31% and 100%, respectively. A measurable increase of NH3 emission from the ND treatment was found with a cumulative NH3 emission of 3.8 ± 1.2 kg N/ha, which was 1.4 times greater than that from the NP treatment (2.7 ± 0.7 kg N/ha). Copyright © 2015. Published by Elsevier B.V.

  19. Nitrous oxide emission related to ammonia-oxidizing bacteria and mitigation options from N fertilization in a tropical soil

    NARCIS (Netherlands)

    Soares, Johnny R.; Cassman, N.; Kielak, A.M.; Pijl, A.S.; do Carmo, J.B.; Lourenço, Késia S.; Laanbroek, H.J.; Cantarella, H.; Kuramae, E.E.

    2016-01-01

    Nitrous oxide (N2O) from nitrogen fertilizers applied to sugarcane has high environmental impact on ethanol production. This study aimed to determine the main microbial processes responsible for the N2O emissions from soil fertilized with different N sources, to identify options to mitigate N2O

  20. Methane, nitrous oxide and ammonia emissions from pigs housed on litter and from stockpiling of spent litter

    KAUST Repository

    Phillips, F. A.; Wiedemann, S. G.; Naylor, T. A.; McGahan, E. J.; Warren, B. R.; Murphy, C. M.; Parkes, Stephen; Wilson, J.

    2016-01-01

    Mitigation of agricultural greenhouse gas emissions is a target area for the Australian Government and the pork industry. The present study measured methane (CH4), nitrous oxide (N2O) and ammonia (NH3) from a deep-litter piggery and litter stockpile over two trials in southern New South Wales, to compare emissions from housing pigs on deep litter with those of pigs from conventional housing with uncovered anaerobic effluent-treatment ponds. Emissions were measured using open-path Fourier transform infrared spectrometry, in conjunction with a backward Lagrangian stochastic model. Manure excretion was determined by mass balance and emission factors (EFs) were developed to report emissions relative to volatile solids and nitrogen (N) input. Nitrous oxide emissions per animal unit (1 AU ≤ 500 kg liveweight) from deep-litter sheds were negligible in winter, and 8.4 g/AU.day in summer. Ammonia emissions were 39.1 in winter and 52.2 g/AU.day in summer, while CH4 emissions were 16.1 and 21.6 g/AU.day in winter and summer respectively. Emission factors averaged from summer and winter emissions showed a CH4 conversion factor of 3.6%, an NH3-N EF of 10% and a N2O-N EF of 0.01 kg N2O-N/kg N excreted. For the litter stockpile, the simple average of summer and winter showed an EF for NH3-N of 14%, and a N2O-N EF of 0.02 kg N2O-N/kg-N of spent litter added to the stockpile. We observed a 66% and 80% decrease in emissions from the manure excreted in litter-based housing with litter stockpiling or without litter stockpiling, compared with conventional housing with an uncovered anaerobic effluent-treatment pond. This provides a sound basis for mitigation strategies that utilise litter-based housing as an alternative to conventional housing with uncovered anaerobic effluent-treatment ponds. © CSIRO 2016.

  1. Methane, nitrous oxide and ammonia emissions from pigs housed on litter and from stockpiling of spent litter

    KAUST Repository

    Phillips, F. A.

    2016-05-05

    Mitigation of agricultural greenhouse gas emissions is a target area for the Australian Government and the pork industry. The present study measured methane (CH4), nitrous oxide (N2O) and ammonia (NH3) from a deep-litter piggery and litter stockpile over two trials in southern New South Wales, to compare emissions from housing pigs on deep litter with those of pigs from conventional housing with uncovered anaerobic effluent-treatment ponds. Emissions were measured using open-path Fourier transform infrared spectrometry, in conjunction with a backward Lagrangian stochastic model. Manure excretion was determined by mass balance and emission factors (EFs) were developed to report emissions relative to volatile solids and nitrogen (N) input. Nitrous oxide emissions per animal unit (1 AU ≤ 500 kg liveweight) from deep-litter sheds were negligible in winter, and 8.4 g/AU.day in summer. Ammonia emissions were 39.1 in winter and 52.2 g/AU.day in summer, while CH4 emissions were 16.1 and 21.6 g/AU.day in winter and summer respectively. Emission factors averaged from summer and winter emissions showed a CH4 conversion factor of 3.6%, an NH3-N EF of 10% and a N2O-N EF of 0.01 kg N2O-N/kg N excreted. For the litter stockpile, the simple average of summer and winter showed an EF for NH3-N of 14%, and a N2O-N EF of 0.02 kg N2O-N/kg-N of spent litter added to the stockpile. We observed a 66% and 80% decrease in emissions from the manure excreted in litter-based housing with litter stockpiling or without litter stockpiling, compared with conventional housing with an uncovered anaerobic effluent-treatment pond. This provides a sound basis for mitigation strategies that utilise litter-based housing as an alternative to conventional housing with uncovered anaerobic effluent-treatment ponds. © CSIRO 2016.

  2. Death from Nitrous Oxide.

    Science.gov (United States)

    Bäckström, Björn; Johansson, Bengt; Eriksson, Anders

    2015-11-01

    Nitrous oxide is an inflammable gas that gives no smell or taste. It has a history of abuse as long as its clinical use, and deaths, although rare, have been reported. We describe two cases of accidental deaths related to voluntary inhalation of nitrous oxide, both found dead with a gas mask covering the face. In an attempt to find an explanation to why the victims did not react properly to oncoming hypoxia, we performed experiments where a test person was allowed to breath in a closed system, with or without nitrous oxide added. Vital signs and gas concentrations as well as subjective symptoms were recorded. The experiments indicated that the explanation to the fact that neither of the descendents had reacted to oncoming hypoxia and hypercapnia was due to the inhalation of nitrous oxide. This study raises the question whether nitrous oxide really should be easily, commercially available. © 2015 American Academy of Forensic Sciences.

  3. Potential nitrous oxide yield of AOA vs. AOB and utilization of carbon and nitrogen in the ammonia oxidizing process in the Pearl River Estuary

    Science.gov (United States)

    Ma, L.; Dai, M.; Tan, S.; Xia, X.; Liu, H.

    2016-12-01

    Nitrous oxide (N2O), a greenhouse gas, is a by-product during ammonia oxidation process, the production of which is often stimulated under low dissolved oxygen (DO) in the estuarine environment. The potential yield of N2O has been considered to be driven by ammonia-oxidizing bacteria (AOB) of Betaproteobacteria & Gammaproteobacteria and/or ammonia-oxidizing archaea (AOA) of Thaumarchaeota. In order to examine the relative importance of AOA and AOB in producing N2O and in modulating the potential N2O yield, arch-amoA, beta-amoA, gamma-amoA encoding for the alpha subunit of the ammonia monooxygenase (AMO) are used as biomarkers to identify the distributions and bioactivities of AOA and AOB in the Pearl River Estuary (PRE). Size fractionation experiments were conducted to distinguish AOA and AOB on particles in different size-fractions of > 3 μm, 0.45-3 μm, and 0.22-0.45 μm. Pure culture of N. maritimusSCM1 was studied as a model organism to identify the organic carbon production during ammonia oxidation by SCM1 strains. Our results show that AOA distributes largely in the free-living state and could adapt to very limited ammonia substrate and low saturation of DO; AOB mainly distributes at the particle-attached state under relative richer ammonia and high DO conditions; however, the RNA/DNA ratio of AOB was higher than that of AOA under the same conditions suggesting AOB is relatively more actively expressed. In the upper reach of PRE, the dominant microorganism in the water column was AOB and the in situ N2O/NH3 therein ranged 0.73-3.74 ‰. In the lower PRE, AOA was dominated, and the in situ N2O/NH3 was of 1.17- 7.32‰. At selected sites, we estimated isotope effect (e) of AOA (eDIC/bulk) as -23.94‰ and AOB (eDIC/bulk) as -56.6‰ to -44.8‰, which is consistent with the studies of pure cultures. The coefficient of C sequestration "k", defined as (C biomass / DIC in situ) / (N biomass / ammonia in situ) to differ the utilization of carbon and nitrogen, of

  4. Comparison of different two-pathway models for describing the combined effect of DO and nitrite on the nitrous oxide production by ammonia-oxidizing bacteria.

    Science.gov (United States)

    Lang, Longqi; Pocquet, Mathieu; Ni, Bing-Jie; Yuan, Zhiguo; Spérandio, Mathieu

    2017-02-01

    The aim of this work is to compare the capability of two recently proposed two-pathway models for predicting nitrous oxide (N 2 O) production by ammonia-oxidizing bacteria (AOB) for varying ranges of dissolved oxygen (DO) and nitrite. The first model includes the electron carriers whereas the second model is based on direct coupling of electron donors and acceptors. Simulations are confronted to extensive sets of experiments (43 batches) from different studies with three different microbial systems. Despite their different mathematical structures, both models could well and similarly describe the combined effect of DO and nitrite on N 2 O production rate and emission factor. The model-predicted contributions for nitrifier denitrification pathway and hydroxylamine pathway also matched well with the available isotopic measurements. Based on sensitivity analysis, calibration procedures are described and discussed for facilitating the future use of those models.

  5. Nitrification gene ratio and free ammonia explain nitrite and nitrous oxide production in urea-amended soils

    Science.gov (United States)

    Substantial efforts have been made to characterize soil nitrous oxide (N2O) emissions following N fertilizer addition. While nitrite (NO2-) is a central regulator of N2O production, NO2- and N2O responses to nitrogen (N) fertilizer amendments still cannot be readily predicted. Our objective was to...

  6. Ammonia and nitrous oxide interactions: Roles of manure organic matter management

    DEFF Research Database (Denmark)

    Petersen, Søren O; Sommer, Sven G

    2011-01-01

    Intensification of livestock production in many parts of the world has led to increasing atmospheric losses of N in connection with storage and field application of manure. Both types of emissions are influenced by manure organic matter content via mechanisms such as composting, crust formation......, mineralization–immobilization turnover, and water retention. Manure management affects the potential for, and balance between, NH3 and N2O emissions. The interaction between NH3 and N2O may be positive (e.g., both emissions are reduced by an airtight cover during storage and stimulated by composting......), or negative (e.g., direct N2O emissions from soil will potentially increase if losses of NH3 are prevented during storage or field application). Emissions of NH3 and N2O negatively affect N use efficiency and the greenhouse gas (GHG) balance of livestock production. Ammonia and N2O emissions and GHG balances...

  7. Effectiveness of urease inhibition on the abatement of ammonia, nitrous oxide and nitric oxide emissions in a non-irrigated Mediterranean barley field.

    Science.gov (United States)

    Abalos, Diego; Sanz-Cobena, Alberto; Misselbrook, Thomas; Vallejo, Antonio

    2012-09-01

    Urea is considered the cheapest and most commonly used form of inorganic N fertilizer worldwide. However, its use is associated with emissions of ammonia (NH(3)), nitrous oxide (N(2)O) and nitric oxide (NO), which have both economic and environmental impact. Urease activity inhibitors have been proposed as a means to reduce NH(3) emissions, although limited information exists about their effect on N(2)O and NO emissions. In this context, a field experiment was carried out with a barley crop (Hordeum vulgare L.) under Mediterranean conditions to test the effectiveness of the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on reducing these gaseous N losses from surface applied urea. Crop yield, soil mineral N concentrations, dissolved organic carbon (DOC), denitrification potential, NH(3), N(2)O and NO fluxes were measured during the growing season. The inclusion of the inhibitor reduced NH(3) emissions in the 30 d following urea application by 58% and net N(2)O and NO emissions in the 95 d following urea application by 86% and 88%, respectively. NBPT addition also increased grain yield by 5% and N uptake by 6%, although neither increase was statistically significant. Under the experimental conditions presented here, these results demonstrate the potential of the urease inhibitor NBPT in abating NH(3), N(2)O and NO emissions from arable soils fertilized with urea, slowing urea hydrolysis and releasing lower concentrations of NH(4)(+) to the upper soil layer. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Catalytic oxidation using nitrous oxide

    Directory of Open Access Journals (Sweden)

    Juan Carlos Beltran-Prieto

    2017-01-01

    Full Text Available Nitrous oxide is a very inert gas used generally as oxidant as it offers some advantage compared with other oxidants such as O2 but a considerably higher temperature (> 526 °C is often required. For particular cases such as the oxidation of sugar alcohols, especially for the oxidation of primary alcohols to aldehydes, N2O has the advantage over O2 of a higher reaction selectivity. In the present paper we present the modelling of oxidation reaction of sugar alcohols using an oxidizing agent in low concentrations, which is important to suppress subsequent oxidation reactions due to the very low residual concentrations of the oxidizing agent. For orientation experiments we chose nitrous oxide generated by thermal decomposition of ammonium nitrate. Kinetic modeling of the reaction was performed after determination of the differential equations that describe the system under study.

  9. Thermal and combined thermal and radiolytic reactions involving nitrous oxide, hydrogen, nitrogen, and ammonia in contact with tank 241-SY-101 simulated waste

    International Nuclear Information System (INIS)

    Bryan, S.A.; Pederson, L.R.

    1996-02-01

    Work described in this report was conducted at Pacific Northwest National Laboratory (PNNL) for the Flammable Gas Safety Project, the purpose of which is to develop information needed to support Westinghouse Hanford Company (WHC) in their efforts to ensure the safe interim storage of wastes at the Hanford Site. Described in this report are the results of tests to evaluate the rates of thermal and combined thermal and radiolytic reactions involving flammable gases in the presence of Tank 241-SY-101 simulated waste. Flammable gases generated by the radiolysis of water and by the thermal and radiolytic decomposition of organic waste constituents may themselves participate in further reactions. Examples include the decomposition of nitrous oxide to yield nitrogen and oxygen, the reaction of nitrous oxide and hydrogen to produce nitrogen and water, and the reaction of nitrogen and hydrogen to produce ammonia. The composition of the gases trapped in bubbles in the wastes might therefore change continuously as a function of the time that the gas bubbles are retained

  10. Nitrous oxide emission from the agriculture in the Netherlands. Outline of effects of manure and ammonia measures; Lachgasemissie uit de Nederlandse landbouw. Verkenning effecten mest- en ammoniakmaatregelen

    Energy Technology Data Exchange (ETDEWEB)

    Kros, J.; De Vries, W.; Oenema, O.; Velthof, G.; Kuikman, P.J.; Van Hove, B. [Divisie Bodem, Alterra, Wageningen Universiteit en Research Centrum, Wageningen (Netherlands)

    2004-03-01

    By means of the model INITIATOR an integral outline was made of the effects of several measures within the framework of the manure and ammonia policy focusing on nitrous oxide emission. The results are compared with the IPCC method. The model INITIATOR is a mechanistic model by means of which the carbon cycle in the Netherlands can be differentiated on a regional scale as a function of land use, type of soil and hydrology. [Dutch] Met behulp van het model INITIATOR is een integrale verkenning gemaakt van de effecten van verschillende maatregelen in het kader van het mest- en ammoniakbeleid op de emissie van Iachgas.Voor de huidige situatie zijn de uitkomsten vergeleken met die van de gangbare IPCC-methode (International Panel on Climate Change)

  11. Nitrous oxide production in intermittently aerated Partial Nitritation-Anammox reactor: oxic N2O production dominates and relates with ammonia removal rate

    DEFF Research Database (Denmark)

    Blum, Jan-Michael; Jensen, Marlene Mark; Smets, Barth F.

    2018-01-01

    Emissions of the greenhouse gas nitrous oxide from the Partial Nitritation-Anammox process are of concern and can determine the carbon footprint of the process. In order to reduce nitrous oxide emissions intermittent aeration regimes have been shown to be a promising mode of operation, possibly due...

  12. Nitrous oxide and perioperative outcomes.

    Science.gov (United States)

    Ko, Hanjo; Kaye, Alan David; Urman, Richard D

    2014-06-01

    There is emerging evidence related to the effects of nitrous oxide on important perioperative patient outcomes. Proposed mechanisms include metabolic effects linked to elevated homocysteine levels and endothelial dysfunction, inhibition of deoxyribonucleic acid and protein formation, and depression of chemotactic migration by monocytes. Newer large studies point to possible risks associated with the use of nitrous oxide, although data are often equivocal and inconclusive. Cardiovascular outcomes such as stroke or myocardial infarction were shown to be unchanged in previous studies, but the more recent Evaluation of Nitrous Oxide in the Gas Mixture for Anesthesia I trial shows possible associations between nitrous oxide and increased cardiovascular and pulmonary complications. There are also possible effects on postoperative wound infections and neuropsychological function, although the multifactorial nature of these complications should be considered. Teratogenicity linked to nitrous oxide use has not been firmly established. The use of nitrous oxide for routine anesthetic care may be associated with significant costs if complications such as nausea, vomiting, and wound infections are taken into consideration. Overall, definitive data regarding the effect of nitrous oxide on major perioperative outcomes are lacking. There are ongoing prospective studies that may further elucidate its role. The use of nitrous oxide in daily practice should be individualized to each patient's medical conditions and risk factors.

  13. Modern chemistry of nitrous oxide

    International Nuclear Information System (INIS)

    Leont'ev, Aleksandr V; Fomicheva, Ol'ga A; Proskurnina, Marina V; Zefirov, Nikolai S

    2001-01-01

    Modern trends of the chemistry of nitrous oxide are discussed. Data on its structure, physical properties and reactivity are generalised. The effect of N 2 O on the environment and the possibility of its utilisation are considered. Attention is focused on the processes in which the oxidising potential of nitrous oxide can be employed. The bibliography includes 329 references.

  14. Modeling the effect of heat fluxes on ammonia and nitrous oxide emissions from an anaerobic swine waste treatment lagoon using artificial neural network

    Science.gov (United States)

    Understanding factors that affect ammonia and nitrous emissions from anaerobic swine waste treatment lagoons or any animal waste receptacles is a necessary first step in deploying potential remediation options. In this study, we examined the various meteorological factors (i.e., air temperatures, s...

  15. 21 CFR 184.1545 - Nitrous oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrous oxide. 184.1545 Section 184.1545 Food and... Substances Affirmed as GRAS § 184.1545 Nitrous oxide. (a) Nitrous oxide (empirical formula N2O, CAS Reg. No.... Nitrous oxide is manufactured by the thermal decomposition of ammonium nitrate. Higher oxides of nitrogen...

  16. Effects of inorganic carbon on the nitrous oxide emissions and microbial diversity of an anaerobic ammonia oxidation reactor.

    Science.gov (United States)

    Zhang, Wenjie; Wang, Dunqiu; Jin, Yue

    2018-02-01

    Inorganic carbon (IC) is important for anaerobic ammonium oxidation (anammox). In this study, the effects of the IC concentration on N 2 O emissions and microbial diversity in an anammox reactor were investigated. N 2 O emissions were positively correlated with IC concentrations, and IC concentrations in the range of 55-130 mg/L were optimal, considering the nitrogen removal rate and N 2 O emissions. High IC concentrations resulted in the formation of CaCO 3 on the surface of anammox granules, which impacted the diffusion conditions of the substrate. Microbial community analysis indicated that high IC concentrations decreased the populations of specific bacteria, such as Achromobacter spanius strain YJART-7, Achromobacter xylosoxidans strain IHB B 6801, and Denitratisoma oestradiolicum clone 20b_15. D. oestradiolicum clone 20b_15 appeared to be the key contributor to N 2 O emissions. High N 2 O emissions may result from changes in organic carbon sources, which lead to denitrification by D. oestradiolicum clone 20b_15. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Nitrous oxide availability.

    Science.gov (United States)

    Murray, M J; Murray, W J

    1980-04-01

    Nitrous oxide (N2O) is marketed as an inhalation anesthetic and as a food ingredient (e.g., whipping cream propellant). In the human, inhalation has been associated with "highs," peripheral nerve damage, mitotic poisoning of bone marrow, psychosis, and mental impairment. Exposure to hypoxemic mixtures has resulted in death. The commercial N2O sources specifically studied were aerosol whipping cream containers (three brands) and 6.5-cm cylinders, or chargers (two brands). The gas content and N2O concentrations of these devices were measured. The aerosol cans, when not shaken, will dispense at least 3 liters of 87 to 90% N2O. Charger misuse may occur when they are substituted for identically designed carbon dioxide (CO2) chargers of a seltzer bottle; 4.3 to 5.0 liters of 93 to 98% N2O is expelled at a controllable rate. The toxicity of these inexpensive N2O products, their high potential for misuse, and the absence of labeling (chargers) argue that their distribution be discontinued.

  18. Combining Urease and Nitrification Inhibitors with Incorporation Reduces Ammonia and Nitrous Oxide Emissions and Increases Corn Yields.

    Science.gov (United States)

    Drury, Craig F; Yang, Xueming; Reynolds, W Dan; Calder, Wayne; Oloya, Tom O; Woodley, Alex L

    2017-09-01

    Less than 50% of applied nitrogen (N) fertilizer is typically recovered by corn ( L.) due to climatic constraints, soil degradation, overapplication, and losses to air and water. Two application methods, two N sources, and two inhibitors were evaluated to reduce N losses and enhance crop uptake. The treatments included broadcast urea (BrUrea), BrUrea with a urease inhibitor (BrUrea+UI), BrUrea with a urease and a nitrification inhibitor (BrUrea+UI+NI), injection of urea ammonium nitrate (InjUAN), and injected with one or both inhibitors (InjUAN+UI, InjUAN+UI+NI), and a control. The BrUrea treatment lost 50% (64.4 kg N ha) of the applied N due to ammonia volatilization, but losses were reduced by 64% with BrUrea+UI+NI (23.0 kg N ha) and by 60% with InjUAN (26.1 kg N ha). Ammonia losses were lower and crop yields were greater in 2014 than 2013 as a result of the more favorable weather when N was applied in 2014. When ammonia volatilization was reduced by adding a urease inhibitor, NO emissions were increased by 30 to 31% with BrUrea+UI and InjUAN+UI compared with BrUrea and InjUAN, respectively. Pollution swapping was avoided when both inhibitors were used (BrUrea+UI+NI, InjUAN+UI+NI) as both ammonia volatilization and NO emissions were reduced, and corn grain yields increased by 5% with BrUrea+UI+NI and by 7% with InjUAN+UI+NI compared with BrUrea and InjUAN, respectively. The combination of two N management strategies (InjUAN+UI+NI) increased yields by 19% (12.9 t ha) compared with BrUrea (10.8 t ha). Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  19. 29 CFR 1910.105 - Nitrous oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Nitrous oxide. 1910.105 Section 1910.105 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.105 Nitrous oxide. The piped systems for the in-plant transfer and distribution of nitrous oxide shall be designed, installed, maintained, and...

  20. Nitrous oxide emissions from estuarine intertidal sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Klaver, G.; Nieuwenhuize, J.; Markusse, R.M.; Vlug, T.; Nat, F.J.W.A. van der

    1995-01-01

    From September 1990 through December 1991 nitrous oxide flux measurements were made at 9 intertidal mud flat sites in the Scheldt Estuary. Nitrous oxide release rates were highly variable both between sites and over time at any one site. Annual nitrous oxide fluxes vary from about 10 mmol N m-2 at

  1. Catalyst for Ammonia Oxidation

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

  2. Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)

    KAUST Repository

    Ngugi, David

    2011-11-28

    Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using 15N isotope tracer analysis. Living termites emitted N 2 at rates ranging from 3.8 to 6.8nmolh -1 (g fresh wt.) -1. However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of 15N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N 2O, ranging from 0.4 to 3.9nmolh -1 (g fresh wt.) -1, providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  3. Nitrous Oxide Production by Abundant Benthic Macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Schramm, Andreas

    of the short-term metabolic induction of gut denitrification is the preferential production of nitrous oxide rather than dinitrogen. On a large scale, gut denitrification in, for instance, Chironomus plumosus larvae can increase the overall nitrous oxide emission of lake sediment by a factor of eight. We...... screened more than 20 macrofauna species for nitrous oxide production and identified filter-feeders and deposit-feeders that occur ubiquitously and at high abundance (e.g., chironomids, ephemeropterans, snails, and mussels) as the most important emitters of nitrous oxide. In contrast, predatory species...... that do not ingest large quantities of microorganisms produced insignificant amounts of nitrous oxide. Ephemera danica, a very abundant mayfly larva, was monitored monthly in a nitrate-polluted stream. Nitrous oxide production by this filter-feeder was highly dependent on nitrate availability...

  4. Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)

    KAUST Repository

    Ngugi, David; Brune, Andreas

    2011-01-01

    Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite

  5. Transformation features in solid nitrous oxide

    International Nuclear Information System (INIS)

    Drobyshev, A.; Aldiyarov, A.; Korshikov, E.; Sokolov, D.; Kurnosov, V.

    2012-01-01

    The transformation features in cryocondensates of nitrous oxide were studied in the process of thermal cycling in the vicinity of the temperature T = 40 K. The research was aimed at figuring out the response of deformation and translational vibrational subsystems of the condensed nitrous oxide to these transformations. The temperature and the nature of thermally stimulated reactions in the films of nitrous oxide cryocondensates were determined. By measuring the vibrational spectra of the samples and by recording the changes in amplitude and position of the absorption bands characteristic of vibrations. Analysis of the IR spectra suggests that the transition from the amorphous state of nitrous oxide to the crystalline one is carried out in several stages, which account for the implementation of relaxation processes related to a particular type of vibrations of a nitrous oxide molecule. The difference in the temperatures of the transitions is determined by activation energies that are typical of this type of oscillation.

  6. 21 CFR 868.1700 - Nitrous oxide gas analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrous oxide gas analyzer. 868.1700 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1700 Nitrous oxide gas analyzer. (a) Identification. A nitrous oxide gas analyzer is a device intended to measure the concentration of nitrous oxide...

  7. Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

    Science.gov (United States)

    Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

    2015-12-01

    Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

  8. Nitrous oxide emissions from wastewater treatment processes

    Science.gov (United States)

    Law, Yingyu; Ye, Liu; Pan, Yuting; Yuan, Zhiguo

    2012-01-01

    Nitrous oxide (N2O) emissions from wastewater treatment plants vary substantially between plants, ranging from negligible to substantial (a few per cent of the total nitrogen load), probably because of different designs and operational conditions. In general, plants that achieve high levels of nitrogen removal emit less N2O, indicating that no compromise is required between high water quality and lower N2O emissions. N2O emissions primarily occur in aerated zones/compartments/periods owing to active stripping, and ammonia-oxidizing bacteria, rather than heterotrophic denitrifiers, are the main contributors. However, the detailed mechanisms remain to be fully elucidated, despite strong evidence suggesting that both nitrifier denitrification and the chemical breakdown of intermediates of hydroxylamine oxidation are probably involved. With increased understanding of the fundamental reactions responsible for N2O production in wastewater treatment systems and the conditions that stimulate their occurrence, reduction of N2O emissions from wastewater treatment systems through improved plant design and operation will be achieved in the near future. PMID:22451112

  9. Nitrous Oxide Emission by Aquatic Macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Nielsen, Lars Peter; Schramm, Andreas

    -term metabolic induction of gut denitrification is the preferential production of nitrous oxide rather than dinitrogen. These observations were made in detailed studies on the larvae of the freshwater insects Chironomus plumosus and Ephemera danica which both can be very abundant in lake and stream sediments......, respectively. Aside from these case studies, we screened more than 20 macrofauna species in various aquatic habitats for nitrous oxide production. Filter- and deposit-feeders that ingest large quantities of microorganisms were the most important emitters of nitrous oxide. In contrast, predatory species that do...... not ingest large quantities of microorganisms produced insignificant amounts of nitrous oxide. With increasing eutrophication, filter- and deposit-feeders often become the dominant feeding guilds of benthic communities. Thus, with increasing nitrate pollution, aquatic macrofauna has the potential to further...

  10. Nitrous oxide emission by aquatic macrofauna

    Science.gov (United States)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter; Brix, Hans; Schramm, Andreas

    2009-01-01

    A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic animals is quantitatively important in nitrate-rich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability in tropical regions and the numeric dominance of filter- and deposit-feeders in eutrophic ecosystems. PMID:19255427

  11. Nitrous Oxide flux measurements under various amendments

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset consists of measurements of soil nitrous oxide emissions from soils under three different amendments: glucose, cellulose, and manure. Data includes the...

  12. Resonating Nitrous Oxide Thruster, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — AeroAstro proposes decomposing nitrous oxide (N2O) as an alternative propellant to existing spacecraft propellants. Decomposing N2O can be used as either a high Isp,...

  13. Nitrous oxide emission by aquatic macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter

    2009-01-01

      A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested...... delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic...... animals is quantitatively important in nitraterich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability...

  14. The role of nitrifier denitrification in the production of nitrous oxide revisited

    NARCIS (Netherlands)

    Wrage-Mönnig, Nicole; Horn, Marcus A.; Well, Reinhard; Müller, Christoph; Velthof, Gerard; Oenema, Oene

    2018-01-01

    Nitrifier denitrification is the reduction of nitrite (NO2 −) by ammonia-oxidizing bacteria. This process may account for up to 100% of nitrous oxide (N2O) emissions from ammonium (NH4 +) in soils and is more significant than classical denitrification under some conditions. Investigations of

  15. Nitrous oxide and global warming

    International Nuclear Information System (INIS)

    Kroeze, C.

    1994-01-01

    The climatic impact of nitrous oxide (N 2 O) emissions is calculated annually for the period 1900-2100, using a globally averaged computer model. Emissions of N 2 O have been increasing up top an estimated 12.7 Tg N/year in 1990 by human activities and global warming. If the current trends continue, emissions are estimated to be 25.7 Tg N/year by 2100, with fossil-fuel use and human food production as major contributors. The resulting equilibrium temperature increase (0.37 degree C) exceeds the forcing derived from climate goals that may be considered environmentally desirable. Limiting equilibrium warming to 0.1 degree C per decade would require anthropogenic-induced and warming-induced N 2 O emissions to be reduced by 80% relative to current trends and to be stabilized from 2050, so that 10.7 Tg N/year is emitted by 2100. To stabilize the current concentration or climate forcing of N 2 , substantially larger cuts are needed. However, even in an optimistic scenario, emissions keep increasing up to 14.4. Tg N/year by 2100. A major reason is the close connection between N 2 O emissions and human food production. Synthetic fertilizer use, land-use change, and production of manure increase almost inevitably as the human population grows. Thus if global warming is to be limited to 0.1 degree C per decade it may be necessary to set emission reductions for other greenhouse gases relatively high to compensate for growth in climatic forcing by N 2 O

  16. High Performance Nitrous Oxide Analyzer for Atmospheric Research, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project targets the development of a highly sensitive gas sensor to monitor atmospheric nitrous oxide. Nitrous oxide is an important species in Earth science...

  17. CHARACTERIZATION OF NITROUS OXIDE EMISSION SOURCES

    Science.gov (United States)

    The report presents a global inventory of nitrous oxide (N2O) based on reevaluation of previous estimates and additions of previously uninventoried source categories. (NOTE: N2O is both a greenhouse gas and a precursor of nitric oxide (NO) which destroys stratospheric ozone.) The...

  18. 41 CFR 50-204.69 - Nitrous oxide.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Nitrous oxide. 50-204.69..., Vapors, Fumes, Dusts, and Mists § 50-204.69 Nitrous oxide. The piped systems for the in-plant transfer and distribution of nitrous oxide shall be designed, installed, maintained, and operated in accordance...

  19. NITROUS OXIDE EMISSIONS FROM FOSSIL FUEL COMBUSTION

    Science.gov (United States)

    The role of coal combustion as a significant global source of nitrous oxide (N2O) emissions was reexamined through on-line emission measurements from six pulverized-coal-fired utility boilers and from laboratory and pilot-scale combustors. The full-scale utility boilers yielded d...

  20. Nitrous Oxide Emissions from Waste Incineration

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Karel; Baxter, D.; Martinec, J.

    2006-01-01

    Roč. 60, č. 1 (2006), s. 78-90 ISSN 0366-6352 R&D Projects: GA AV ČR(CZ) IAA4072201 Institutional research plan: CEZ:AV0Z40720504 Keywords : nitrous oxide * waste * incineration Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.360, year: 2006

  1. Recreational nitrous oxide use: Prevalence and risks

    NARCIS (Netherlands)

    van Amsterdam, Jan; Nabben, Ton; van den Brink, Wim

    2015-01-01

    Nitrous oxide (N2O; laughing gas) is clinically used as a safe anesthetic (dentistry, ambulance, childbirth) and appreciated for its anti-anxiety effect. Since five years, recreational use of N2O is rapidly increasing especially in the dance and festival scene. In the UK, N2O is the second most

  2. Nitrous oxide emissions of energy production

    International Nuclear Information System (INIS)

    Kinnunen, L.

    1998-01-01

    The share of energy production of the world-wide total N 2 O emissions is about 10 %. In 1991 the N 2 O emissions estimated to be up to 30 %. The previous estimates based on incorrect measurements. The measurement methods have been improved during the past few years. The present measurements have shown that the share of the combustion of fossil fuels is about 2.0 % and the share biomass combustion about 5.0 % of the total. The uncertainty of the values can be few percentage units. According to the present measurements the share of natural emissions and the fertilizers of the total N 2 O emissions is up to 60 %. The formation of nitrous oxide has been studied widely in various countries in the world. In Finland nitrous oxide has been studied in the national LIEKKI research programme. As a result of the research carried out in the programme it has been possible to reduce the formation of N 2 O by using appropriate catalysts and combustion technologies. Nitrous oxide is formed e.g. in fluidized-bed combustion of nitrogen containing fuels. The combustion temperature of other combustion methods is so high that the gas disintegrates in the furnace. By the new methods the nitrous oxide emissions of the fluidized-bed combustion has been possible to reduce from 100-200 ppm to the level less than 50 ppm of the flue gas volume. The Japanese research has shown that the nitrous oxide emissions of bubbling beds vary in between 58 - 103 ppm, but when combusting paper the emissions are 6 - 29 ppm. The corresponding value of circulating fluidized beds is 40 - 153 ppm

  3. Final Report for DOE grant no. DE-FG02-04ER63883: Can soil genomics predict the impact of precipitation on nitrous oxide flux from soil

    Energy Technology Data Exchange (ETDEWEB)

    Egbert Schwartz

    2008-12-15

    Nitrous oxide is a potent greenhouse gas that is released by microorganisms in soil. However, the production of nitrous oxide in soil is highly variable and difficult to predict. Future climate change may have large impacts on nitrous oxide release through alteration of precipitation patterns. We analyzed DNA extracted from soil in order to uncover relationships between microbial processes, abundance of particular DNA sequences and net nitrous oxide fluxes from soil. Denitrification, a microbial process in which nitrate is used as an electron acceptor, correlated with nitrous oxide flux from soil. The abundance of ammonia oxidizing archaea correlated positively, but weakly, with nitrous oxide production in soil. The abundance of bacterial genes in soil was negatively correlated with gross nitrogen mineralization rates and nitrous oxide release from soil. We suggest that the most important control over nitrous oxide production in soil is the growth and death of microorganisms. When organisms are growing nitrogen is incorporated into their biomass and nitrous oxide flux is low. In contrast, when microorganisms die, due to predation or infection by viruses, inorganic nitrogen is released into the soil resulting in nitrous oxide release. Higher rates of precipitation increase access to microorganisms by predators or viruses through filling large soil pores with water and therefore can lead to large releases of nitrous oxide from soil. We developed a new technique, stable isotope probing with 18O-water, to study growth and mortality of microorganisms in soil.

  4. 78 FR 6400 - Results of FAA Nitrous Oxide BLEVE Characterization Testing

    Science.gov (United States)

    2013-01-30

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Results of FAA Nitrous Oxide BLEVE Characterization Testing AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of public... FAA sponsored testing of nitrous oxide (N 2 O) characteristics. Nitrous oxide is an important oxidizer...

  5. Instantaneous global nitrous oxide photochemical rates

    International Nuclear Information System (INIS)

    Johnston, H.S.; Serang, O.; Podolske, J.

    1979-01-01

    In recent years, vertical profiles of nitrous oxide have been measured by balloon up to midstratosphere at several latitudes between 63 0 N and 73 0 S, including one profile in the tropical zone at 9 0 N. Two rocket flights measured nitrous oxide mixing ratios at 44 and 49 km. From these experimental data plus a large amount of interpolation and extrapolation, we have estimated a global distribution of nitrous oxide up to the altitude of 50 km. With standard global distributions of oxygen and ozone we carried out instantaneous, three-dimensional, global photochemical calculations, using recently measured temperature-dependent cross sections for nitrous oxide. The altitude of maximum photolysis rate of N 2 O is about 30 km at all latitudes, and the rate of photolysis is a maximum in tropical latitudes. The altitude of maximum rate of formation of nitric oxide is latitude dependent, about 26 km at the equator, about 23 km over temperate zones, and 20 km at the summer pole. The global rate of N 2 O destruction is 6.2 x 10 27 molecules s -1 , and the global rate of formation of NO from N 2 O is 1.4 x 10 27 molecules s -1 . The global N 2 O inventory divided by the stratospheric loss rate gives a residence time of about 175 years with respect to this loss process. From the global average N 2 O profile a vertical eddy diffusion profile was derived, and this profile agrees very closely with that of Stewart and Hoffert

  6. Nitrous oxide-based techniques versus nitrous oxide-free techniques for general anaesthesia.

    Science.gov (United States)

    Sun, Rao; Jia, Wen Qin; Zhang, Peng; Yang, KeHu; Tian, Jin Hui; Ma, Bin; Liu, Yali; Jia, Run H; Luo, Xiao F; Kuriyama, Akira

    2015-11-06

    Nitrous oxide has been used for over 160 years for the induction and maintenance of general anaesthesia. It has been used as a sole agent but is most often employed as part of a technique using other anaesthetic gases, intravenous agents, or both. Its low tissue solubility (and therefore rapid kinetics), low cost, and low rate of cardiorespiratory complications have made nitrous oxide by far the most commonly used general anaesthetic. The accumulating evidence regarding adverse effects of nitrous oxide administration has led many anaesthetists to question its continued routine use in a variety of operating room settings. Adverse events may result from both the biological actions of nitrous oxide and the fact that to deliver an effective dose, nitrous oxide, which is a relatively weak anaesthetic agent, needs to be given in high concentrations that restrict oxygen delivery (for example, a common mixture is 30% oxygen with 70% nitrous oxide). As well as the risk of low blood oxygen levels, concerns have also been raised regarding the risk of compromising the immune system, impaired cognition, postoperative cardiovascular complications, bowel obstruction from distention, and possible respiratory compromise. To determine if nitrous oxide-based anaesthesia results in similar outcomes to nitrous oxide-free anaesthesia in adults undergoing surgery. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10); MEDLINE (1966 to 17 October 2014); EMBASE (1974 to 17 October 2014); and ISI Web of Science (1974 to 17 October 2014). We also searched the reference lists of relevant articles, conference proceedings, and ongoing trials up to 17 October 2014 on specific websites (http://clinicaltrials.gov/, http://controlled-trials.com/, and http://www.centerwatch.com). We included randomized controlled trials (RCTs) comparing general anaesthesia where nitrous oxide was part of the anaesthetic technique used for the induction or maintenance of general

  7. Greenhouse effect due to atmospheric nitrous oxide

    Science.gov (United States)

    Yung, Y. L.; Wang, W. C.; Lacis, A. A.

    1976-01-01

    The greenhouse effect due to nitrous oxide in the present atmosphere is about 0.8 K. Increase in atmospheric N2O due to perturbation of the nitrogen cycle by man may lead to an increase in surface temperature as large as 0.5 K by 2025, or 1.0 K by 2100. Other climatic effects of N2O are briefly discussed.

  8. Nitrous oxide emissions from fertilized soil: Can we manage it?

    Science.gov (United States)

    Cropped fields in the upper Midwest have the potential to emit nitrous oxide (N2O) and nitric oxide (NO) gases resulting from soil transformation of nitrogen (N) fertilizers applied to crops such as corn and potatoes. Nitrous oxide is a potent greenhouse and also an important in ozone depleting che...

  9. Fact and Fiction of Nitrous Oxide Production By Nitrification

    Science.gov (United States)

    Stein, L. Y.; Kozlowski, J.; Stieglmeier, M.; Klotz, M. G.; Schleper, C.

    2014-12-01

    An accepted dogma in nitrification research is that ammonia-oxidizing bacteria (AOB) produce a modicum of nitrous oxide (N2O) during nitritation via incomplete oxidation of hydroxylamine, and substantially more at low oxygen concentrations via nitrifier denitrification.The nitrifier denitrification pathway involves the reduction of nitrite to N2O via nitric oxide and was thought to require activities of a copper-containing nitrite reductase (NirK) and nitric oxide reductase (NorB); inventory encoded in most, but not all AOB genome sequences. The discovery of nirK genes in ammonia-oxidizing Thaumarchaeota (AOA) resulted in a slew of publications stating that AOA must also perform nitrifier denitrification and, due to their high abundance, must control the majority of nitrification-linked N2O emissions. Prior to a publication by Stieglmeier et al. (2014), which definitively showed a lack of nitrifier denitrification by two axenic AOA cultures, other researchers relied on enrichment cultures, negative data, and heavy inferencing without direct demonstration of either a functional pathway or involvement of specific genes or enzymes. AOA genomes lack recognizable nitric oxide reductases and thermophilic AOA also lack nirK genes. Physiological and microrespirometry experiments with axenic AOB and AOA cultures allowed us to demonstrate that: 1) AOB produce N2O via nitrifier denitrification even though some lack annotated nirK and/or norB genes; 2) nitrifier denitrification by AOB is reliant on nitric oxide but ammonia oxidation is not; 3) ammonia oxidation by AOA is reliant on production of nitric oxide; 4) AOA are incapable of generating N2O via nitrifier denitrification; 5) N2O production by AOA is from chemical interactions between NO and media components, most likely not by enzyme activity. Our results reveal operation of different N oxide transformation pathways in AOB and AOA governed by different environmental controls and involving different mechanisms of N2O

  10. Emission of nitrous oxide during combustion of organic fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Gol' dberg, A.S.

    1990-11-01

    Analyzes formation of nitrogen oxides during combustion of coal, natural gas and mazout: chemical reactions that lead to formation of nitrous oxide during coal combustion, reaction kinetics and reaction yields, factors that influence emission of nitrogen oxides from a furnace, factors that influence formation of nitrous oxide (temperature effects, air excess ratio, coal burnout degree, etc.), effects of fuel type and its chemical composition, effects of flue gas desulfurization and denitrification methods on nitrous oxide yield. Analyses show that yield of nitrous oxide is low and does not exceed 5 cm{sup 3}/m{sup 3} flue gas (0.0005%). However chemical reactions of nitrogen oxides, sulfur dioxide and water vapor in the atmosphere are said to form additional quantities of nitrous oxide which negatively influence the ozone layer. 4 refs.

  11. Nitrous Oxide/Paraffin Hybrid Rocket Engines

    Science.gov (United States)

    Zubrin, Robert; Snyder, Gary

    2010-01-01

    Nitrous oxide/paraffin (N2OP) hybrid rocket engines have been invented as alternatives to other rocket engines especially those that burn granular, rubbery solid fuels consisting largely of hydroxyl- terminated polybutadiene (HTPB). Originally intended for use in launching spacecraft, these engines would also be suitable for terrestrial use in rocket-assisted takeoff of small airplanes. The main novel features of these engines are (1) the use of reinforced paraffin as the fuel and (2) the use of nitrous oxide as the oxidizer. Hybrid (solid-fuel/fluid-oxidizer) rocket engines offer advantages of safety and simplicity over fluid-bipropellant (fluid-fuel/fluid-oxidizer) rocket en - gines, but the thrusts of HTPB-based hybrid rocket engines are limited by the low regression rates of the fuel grains. Paraffin used as a solid fuel has a regression rate about 4 times that of HTPB, but pure paraffin fuel grains soften when heated; hence, paraffin fuel grains can, potentially, slump during firing. In a hybrid engine of the present type, the paraffin is molded into a 3-volume-percent graphite sponge or similar carbon matrix, which supports the paraffin against slumping during firing. In addition, because the carbon matrix material burns along with the paraffin, engine performance is not appreciably degraded by use of the matrix.

  12. Successful use of nitrous oxide during lumbar punctures: A call for nitrous oxide in pediatric oncology clinics.

    Science.gov (United States)

    Livingston, Mylynda; Lawell, Miranda; McAllister, Nancy

    2017-11-01

    Numerous reports describe the successful use of nitrous oxide for analgesia in children undergoing painful procedures. Although shown to be safe, effective, and economical, nitrous oxide use is not yet common in pediatric oncology clinics and few reports detail its effectiveness for children undergoing repeated lumbar punctures. We developed a nitrous oxide clinic, and undertook a review of pediatric oncology lumbar puncture records for those patients receiving nitrous oxide in 2011. No major complications were noted. Minor complications were noted in 2% of the procedures. We offer guidelines for establishing such a clinic. © 2017 Wiley Periodicals, Inc.

  13. Source of Nitrous Oxide Emissions during the Cow Manure Composting Process as Revealed by Isotopomer Analysis of and amoA Abundance in Betaproteobacterial Ammonia-Oxidizing Bacteria▿ †

    Science.gov (United States)

    Maeda, Koki; Toyoda, Sakae; Shimojima, Ryosuke; Osada, Takashi; Hanajima, Dai; Morioka, Riki; Yoshida, Naohiro

    2010-01-01

    A molecular analysis of betaproteobacterial ammonia oxidizers and a N2O isotopomer analysis were conducted to study the sources of N2O emissions during the cow manure composting process. Much NO2−-N and NO3−-N and the Nitrosomonas europaea-like amoA gene were detected at the surface, especially at the top of the composting pile, suggesting that these ammonia-oxidizing bacteria (AOB) significantly contribute to the nitrification which occurs at the surface layer of compost piles. However, the 15N site preference within the asymmetric N2O molecule (SP = δ15Nα − δ15Nβ, where 15Nα and 15Nβ represent the 15N/14N ratios at the center and end sites of the nitrogen atoms, respectively) indicated that the source of N2O emissions just after the compost was turned originated mainly from the denitrification process. Based on these results, the reduction of accumulated NO2−-N or NO3−-N after turning was identified as the main source of N2O emissions. The site preference and bulk δ15N results also indicate that the rate of N2O reduction was relatively low, and an increased value for the site preference indicates that the nitrification which occurred mainly in the surface layer of the pile partially contributed to N2O emissions between the turnings. PMID:20048060

  14. Community Composition of Nitrous Oxide-Related Genes in Salt Marsh Sediments Exposed to Nitrogen Enrichment.

    Science.gov (United States)

    Angell, John H; Peng, Xuefeng; Ji, Qixing; Craick, Ian; Jayakumar, Amal; Kearns, Patrick J; Ward, Bess B; Bowen, Jennifer L

    2018-01-01

    Salt marshes provide many key ecosystem services that have tremendous ecological and economic value. One critical service is the removal of fixed nitrogen from coastal waters, which limits the negative effects of eutrophication resulting from increased nutrient supply. Nutrient enrichment of salt marsh sediments results in higher rates of nitrogen cycling and, commonly, a concurrent increase in the flux of nitrous oxide, an important greenhouse gas. Little is known, however, regarding controls on the microbial communities that contribute to nitrous oxide fluxes in marsh sediments. To address this disconnect, we generated profiles of microbial communities and communities of micro-organisms containing specific nitrogen cycling genes that encode several enzymes ( amoA, norB, nosZ) related to nitrous oxide flux from salt marsh sediments. We hypothesized that communities of microbes responsible for nitrogen transformations will be structured by nitrogen availability. Taxa that respond positively to high nitrogen inputs may be responsible for the elevated rates of nitrogen cycling processes measured in fertilized sediments. Our data show that, with the exception of ammonia-oxidizing archaea, the community composition of organisms involved in the production and consumption of nitrous oxide was altered under nutrient enrichment. These results suggest that previously measured rates of nitrous oxide production and consumption are likely the result of changes in community structure, not simply changes in microbial activity.

  15. Acetylene and oxygen as inhibitors of nitrous oxide production in Nitrosomonas europaea and Nitrosospira briensis: a cautionary tale

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Oenema, O.; Laanbroek, H.J.

    2004-01-01

    Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N2O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C2H2) and large partial pressures of oxygen (O2) are used to distinguish between these sources. C2H2 inhibits

  16. Nitrous oxide-forming codenitrification catalyzed by cytochrome P450nor.

    Science.gov (United States)

    Su, Fei; Takaya, Naoki; Shoun, Hirofumi

    2004-02-01

    Intact cells of the denitrifying fungus Fusarium oxysporum were previously shown to catalyze codenitrification to form a hybrid nitrous oxide (N2O) species from nitrite and other nitrogen compounds such as azide and ammonia. Here we show that cytochrome P450nor can catalyze the codenitrification reaction to form N2O from nitric oxide (NO) but not nitrite, and azide or ammonia. The results show that the direct substrate of the codenitrification by intact cells should not be nitrite but NO, which is formed from nitrite by the reaction of a dissimilatory nitrite reductase.

  17. Biochar and soil nitrous oxide emissions

    Directory of Open Access Journals (Sweden)

    Carlos Francisco Brazão Vieira Alho

    2012-05-01

    Full Text Available The objective of this work was to evaluate the effect of biochar application on soil nitrous oxide emissions. The experiment was carried out in pots under greenhouse conditions. Four levels of ground commercial charcoal of 2 mm (biochar were evaluated in a sandy Albaqualf (90% of sand: 0, 3, 6, and 9 Mg ha-1. All treatments received 100 kg ha-1 of N as urea. A cubic effect of biochar levels was observed on the N2O emissions. Biochar doses above 5 Mg ha-1 started to mitigate the emissions in the evaluated soil. However, lower doses promote the emissions.

  18. Nitrous oxide emission from soils amended with crop residues

    NARCIS (Netherlands)

    Velthof, G.L.; Kuikman, P.J.; Oenema, O.

    2002-01-01

    Crop residues incorporated in soil are a potentially important source of nitrous oxide (N2O), though poorly quantified. Here, we report on the N2O emission from 10 crop residues added to a sandy and a clay soil, both with and without additional nitrate (NO3-). In the sandy soil, total nitrous oxide

  19. NITROUS OXIDE CONCENTRATIONS IN SMALL STREAMS OF THE GEORGIA PIEDMONT

    Science.gov (United States)

    We are measuring the dissolved nitrous oxide concentration in 17 headwater streams in the South Fork Broad River, Georgia watershed on a monthly basis. The selected small streams drain watersheds dominated by forest, pasture, developed, or mixed land uses. Nitrous oxide concentr...

  20. Catalytic abatement of nitrous oxide from nitric and production

    NARCIS (Netherlands)

    Oonk, J.

    1998-01-01

    Nitric acid production is identified as a main source of nitrous oxide. Options for emission reduction however are not available. TNO and Hydro Agri studied the technological and economic feasibility of catalytic decomposition of nitrous oxide in nitric acid tail-gases. Although in literature

  1. Laryngospasm With Apparent Aspiration During Sedation With Nitrous Oxide.

    Science.gov (United States)

    Babl, Franz E; Grindlay, Joanne; Barrett, Michael Joseph

    2015-11-01

    Nitrous oxide and oxygen mixture has become increasingly popular for the procedural sedation and analgesia of children in the emergency department. In general, nitrous oxide is regarded as a very safe agent according to large case series. We report a case of single-agent nitrous oxide sedation of a child, complicated by laryngospasm and radiographically confirmed bilateral upper lobe pulmonary opacities. Although rarely reported with parenteral sedative agents, laryngospasm and apparent aspiration has not been previously reported in isolated nitrous oxide sedation. This case highlights that, similar to other sedative agents, nitrous oxide administration also needs to be conducted by staff and in settings in which airway emergencies can be appropriately managed. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  2. Dose-response and concentration-response relation of rocuronium infusion during propofol nitrous oxide and isoflurane nitrous oxide anaesthesia

    NARCIS (Netherlands)

    Kansanaho, M; Olkkola, KT; Wierda, JMKH

    The dose-response and concentration-response relation of rocuronium infusion was studied in 20 adult surgical patients during proporfol-nitrous oxide and isoflurane (1 MAC) -nitrous oxide anaesthesia. Neuromuscular block was kept constant, initially at 90% and then at 50% with a closed-loop feedback

  3. Active sites in Fe/ZSM-5 for nitrous oxide decomposition and benzene hydroxylation with nitrous oxide

    NARCIS (Netherlands)

    Sun, K.; Xia, H.; Feng, Z.; Santen, van R.A.; Hensen, E.J.M.; Li, Can

    2008-01-01

    The effect of the iron content and the pretreatment conditions of Fe/ZSM-5 catalysts on the Fe speciation and the catalytic activities in nitrous oxide decomposition and benzene hydroxylation with nitrous oxide has been investigated. Iron-containing ZSM-5 zeolites with varying iron content (Fe/Al =

  4. Nitrate reductase and nitrous oxide production by Fusarium oxysporum 11dn1 under aerobic and anaerobic conditions.

    Science.gov (United States)

    Kurakov, A V; Nosikov, A N; Skrynnikova, E V; L'vov, N P

    2000-08-01

    The fungus Fusarium oxysporum 11dn1 was found to be able to grow and produce nitrous oxide on nitrate-containing medium in anaerobic conditions. The rate of nitrous oxide formation was three to six orders of magnitude lower than the rates of molecular nitrogen production by common denitrifying bacteria. Acetylene and ammonia did not affect the release of nitrous oxide release. It was shown that under anaerobic conditions fast increase of nitrate reductase activity occurred, caused by the synthesis of enzyme de novo and protein dephosphorylation. Reverse transfer of the mycelium to aerobic conditions led to a decline in nitrate reductase activity and stopped nitrous oxide production. The presence of two nitrate reductases was shown, which differed in molecular mass, location, temperature optima, and activity in nitrate- and ammonium-containing media. Two enzymes represent assimilatory and dissimilatory nitrate reductases, which are active in aerobic and anaerobic conditions, respectively.

  5. Nitrous oxide emissions at low temperatures

    International Nuclear Information System (INIS)

    Martikainen, P.J.

    2002-01-01

    Microbial processes in soil are generally stimulated by temperature, but at low temperatures there are anomalies in the response of microbial activities. Soil physical-chemical characteristics allow existence of unfrozen water in soil also at temperatures below zero. Therefore, some microbial activities, including those responsible for nitrous oxide (N 2 0) production, can take place even in 'frozen' soil. Nitrous oxide emissions during winter are important even in boreal regions where they can account for more than 50% of the annual emissions. Snow pack therefore has great importance for N 2 0 emissions, as it insulates soil from the air allowing higher temperatures in soil than in air, and possible changes in snoav cover as a result of global warming would thus affect the N 2 0 emission from northern soils. Freezing-thawing cycles highly enhance N 2 0 emissions from soil, probably because microbial nutrients, released from disturbed soil aggregates and lysed microbial cells, support microbial N 2 0 production. However, the overall interactions between soil physics, chemistry, microbiology and N 2 0 production at low temperatures, including effects of freezing-thawing cycles, are still poorly known. (au)

  6. Exposure of nitrous oxide to X-rays

    International Nuclear Information System (INIS)

    Yanagida, H.

    1980-01-01

    A study was performed to determine how much NO and NO 2 is produced when nitrous oxide is exposed to X-radiation. Polyethylene bottles filled with either nitrous oxide alone or with nitrous oxide and 30% oxygen were placed 30 cm from the X-ray tube at a standard X-ray beam setting for chest fluoroscopy for 0 to 5 minutes. In the bottles filled with nitrous oxide alone, the production of NO was not affected by the duration of X-ray exposure, but the longer duration of X-ray exposure produced a larger amount of NO 2 . In the bottles filled with nitrous oxide and 30% oxygen, the longer duration of X-ray exposure produced larger amounts of both NO and NO 2 . These findings confirmed a previous investigation in which nitrous oxide was not inert under X-ray exposure. As the presence of oxygen plays an important role in the oxidation of nitrous oxide under X-ray exposure, this study suggests another potentially hazardous interaction that may occur secondary to the administration of an anaesthetic in the presence of X-irradiation as in pulmonary angiography, cardiac catheterisation, and fluoroscopic bronchoscopy or biopsy. (author)

  7. Use of Nitrous Oxide in Dermatology: A Systematic Review.

    Science.gov (United States)

    Brotzman, Erica A; Sandoval, Laura F; Crane, Jonathan

    2018-05-01

    Many dermatologic procedures are painful and can be distressing to patients. To determine whether nitrous oxide has been used in dermatology and whether literature supports its use in terms of providing analgesia and anxiety associated with dermatologic procedures. A search of PubMed and Cochrane databases was conducted through July 15, 2016, to identify studies involving nitrous oxide use in dermatology. Eight studies were identified and reviewed. The use of nitrous oxide/oxygen mixture resulted in a significant reduction in pain when used for photodynamic therapy, botulinum toxin therapy for hyperhidrosis of both the palms and axilla, aesthetic procedures involving various laser procedures, and in the treatment of bed sores and leg ulcers. However, pain scores were higher when nitrous oxide/oxygen was used in the debridement of chronic ulcers when compared with the use of topical anesthesia. In addition, nitrous oxide has been reported effective at reducing pain in hair transplants, dermabrasion, excision and repairs, and pediatric procedures. Current literature provides some evidence that nitrous oxide, used alone or as adjunct anesthesia, is effective at providing analgesia for many dermatologic procedures. Nitrous oxide has many potential applications in dermatology; however, further evidence from randomized controlled trials is needed.

  8. Nitrous oxide-induced slow and delta oscillations.

    Science.gov (United States)

    Pavone, Kara J; Akeju, Oluwaseun; Sampson, Aaron L; Ling, Kelly; Purdon, Patrick L; Brown, Emery N

    2016-01-01

    Switching from maintenance of general anesthesia with an ether anesthetic to maintenance with high-dose (concentration >50% and total gas flow rate >4 liters per minute) nitrous oxide is a common practice used to facilitate emergence from general anesthesia. The transition from the ether anesthetic to nitrous oxide is associated with a switch in the putative mechanisms and sites of anesthetic action. We investigated whether there is an electroencephalogram (EEG) marker of this transition. We retrospectively studied the ether anesthetic to nitrous oxide transition in 19 patients with EEG monitoring receiving general anesthesia using the ether anesthetic sevoflurane combined with oxygen and air. Following the transition to nitrous oxide, the alpha (8-12 Hz) oscillations associated with sevoflurane dissipated within 3-12 min (median 6 min) and were replaced by highly coherent large-amplitude slow-delta (0.1-4 Hz) oscillations that persisted for 2-12 min (median 3 min). Administration of high-dose nitrous oxide is associated with transient, large amplitude slow-delta oscillations. We postulate that these slow-delta oscillations may result from nitrous oxide-induced blockade of major excitatory inputs (NMDA glutamate projections) from the brainstem (parabrachial nucleus and medial pontine reticular formation) to the thalamus and cortex. This EEG signature of high-dose nitrous oxide may offer new insights into brain states during general anesthesia. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  9. Dentists' and Parents' Attitude Toward Nitrous Oxide Use in Kuwait.

    Science.gov (United States)

    Alkandari, Sarah A; Almousa, Fatemah; Abdulwahab, Mohammad; Boynes, Sean G

    2016-01-01

    The aim of this study was to investigate the attitude of dentists in Kuwait toward the use of nitrous oxide sedation as a behavior management technique (BMT) for pediatric patients and assess their training in nitrous oxide sedation. In addition, we assessed parents' knowledge of and attitude toward the use of nitrous oxide as a BMT for their children. The objective was to determine if nitrous oxide sedation is being provided and utilized as a means to enhance dental care for pediatric patients. A cross-sectional survey was randomly distributed to both groups of interest: parents accompanying their children to the dentist and licensed dentists in Kuwait. Participants had to meet certain inclusion criteria to be included in the survey and had to complete the entire questionnaire to be part of the analysis. A total of 381 parents completed the questionnaires. The majority of parents responded that they were unaware of nitrous oxide sedation and were not aware of it as a BMT (79%). Two thirds of the parent would accept nitrous oxide sedation if recommended by a dentist treating their children. Two hundred and one dentists completed the survey and met the inclusion criteria. The majority (74.5%) of dentists were willing to use nitrous oxide as a BMT. However, only 6% were utilizing nitrous oxide sedation and providing it to their child patient if indicated. The main reasons for this huge gap are lack of facilities/equipment and lack of training as indicated by the dentists. This study showed that parents are accepting nitrous oxide sedation as a BMT for their children. It also showed the willingness of the dentists to provide such BMT to their patients. The lack of training and lack of equipment are the main barriers to providing such service to the patients. More training courses and more facilities should be provided to eliminate such barriers.

  10. [Sedation with nitrous oxide in daily practice].

    Science.gov (United States)

    Martens, Luc C; Marks, Luc A

    2003-01-01

    Conscious sedation is recommended, together with behaviour management techniques, to facilitate treatment of dental fear or dental phobia patients. In this article the authors focus on inhalation sedation by means of nitrous oxide. The procedures and indications are explained and illustrated with clinical cases. On the strength of the literature and their own experience the authors reach the conclusion that Inhalation sedation is a kind of pharmacological behaviour management and an important additional tool to increase patient cooperation. Inhalation sedation can only be performed by trained practitioners under internationally accepted safety conditions. Inhalation sedation has a future in Belgium providing the appropriate law is adapted. This technique deserves a place in the dental curriculum.

  11. Recreational nitrous oxide use: Prevalence and risks.

    Science.gov (United States)

    van Amsterdam, Jan; Nabben, Ton; van den Brink, Wim

    2015-12-01

    Nitrous oxide (N2O; laughing gas) is clinically used as a safe anesthetic (dentistry, ambulance, childbirth) and appreciated for its anti-anxiety effect. Since five years, recreational use of N2O is rapidly increasing especially in the dance and festival scene. In the UK, N2O is the second most popular recreational drug after cannabis. In most countries, nitrous oxide is a legal drug that is widely available and cheap. Last month prevalence of use among clubbers and ravers ranges between 40 and almost 80 percent. Following one inhalation, mostly from a balloon, a euphoric, pleasant, joyful, empathogenic and sometimes hallucinogenic effect is rapidly induced (within 10 s) and disappears within some minutes. Recreational N2O use is generally moderate with most users taking less than 10 balloons of N2O per episode and about 80% of the users having less than 10 episodes per year. Side effects of N2O include transient dizziness, dissociation, disorientation, loss of balance, impaired memory and cognition, and weakness in the legs. When intoxicated accidents like tripping and falling may occur. Some fatal accidents have been reported due to due to asphyxia (hypoxia). Heavy or sustained use of N2O inactivates vitamin B12, resulting in a functional vitamin B12 deficiency and initially causing numbness in fingers, which may further progress to peripheral neuropathy and megaloblastic anemia. N2O use does not seem to result in dependence. Considering the generally modest use of N2O and its relative safety, it is not necessary to take legal measures. However, (potential) users should be informed about the risk of vitamin B12-deficiency related neurological and hematological effects associated with heavy use. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Nitrous oxide induced myeloneuropathy: a case report.

    Science.gov (United States)

    Rheinboldt, Matt; Harper, Derrick; Parrish, David; Francis, Kirenza; Blase, John

    2014-02-01

    We report the case of a 35-year-old male with a history of chronic, escalating nitrous oxide abuse who presented to the ER with a history of recent onset generalized weakness, altered sensorium, abnormal posturing of the hands, urinary complaints, and decreased balance. Physical examination was notable for pathologically brisk reflexes in all extremities, generalized flexion contracture of the fingers, decreased sensation in a stocking and glove distribution, and a weakly positive Babinski sign. The patient was noted to be a poor historian with decreased attention and concentration though otherwise generally alert and oriented. No discrete sensory level in the chest or trunk was detected, and the overall clinical appearance was felt to be most compatible with a mixed myeloneuropathic pattern of central and peripheral involvement. Laboratory findings were normal and noncontributory. Cervical spine MRI subsequently performed to rule out cord compression, intrinsic spinal cord mass, or demyelinating disease was notable for a long segment of increased T2 signal extending from C2-C3 to C6-C7 localizing to the dorsal columns of the cord in a typical "inverted V" fashion. No associated cord expansion was seen nor was there evidence of extrinsic compression; faint associated contrast enhancement was observed on post-gadolinium images. Further evaluation with nerve conduction velocity and electromyographic testing was deferred. Based on the exam findings, clinical history, and presentation, a diagnosis of nitrous oxide-related myeloneuropathy was made, and treatment with high-dose vitamin B12 supplementation was instituted. Recovery has been slow to date.

  13. Quantification of Nitrous Oxide from Fugitive Emissions by Tracer Dilution Method using a Mobile Real-time Nitrous Oxide Analyzer

    Science.gov (United States)

    Mønster, J.; Rella, C.; Jacobson, G. A.; He, Y.; Hoffnagle, J.; Scheutz, C.

    2012-12-01

    Nitrous oxide is a powerful greenhouse gas considered 298 times stronger than carbon dioxide on a hundred years term (Solomon et al. 2007). The increasing global concentration is of great concern and is receiving increasing attention in various scientific and industrial fields. Nitrous oxide is emitted from both natural and anthropogenic sources. Inventories of source specific fugitive nitrous oxide emissions are often estimated on the basis of modeling and mass balance. While these methods are well-developed, actual measurements for quantification of the emissions can be a useful tool for verifying the existing estimation methods as well as providing validation for initiatives targeted at lowering unwanted nitrous oxide emissions. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001), in which a tracer gas is released at the source location at a known flow. The ratio of downwind concentrations of both the tracer gas and nitrous oxide gives the ratios of the emissions rates. This tracer dilution method can be done with both stationary and mobile measurements; in either case, real-time measurements of both tracer and analyte gas is required, which places high demands on the analytical detection method. To perform the nitrous oxide measurements, a novel, robust instrument capable of real-time nitrous oxide measurements has been developed, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. We present the results of the laboratory and field tests of this instrument in both California and Denmark. Furthermore, results are presented from measurements using the mobile plume method with a tracer gas (acetylene) to quantify the nitrous oxide and methane emissions from known sources such as waste water treatment plants and composting facilities. Nitrous oxide (blue) and methane (yellow) plumes downwind from a waste water treatment facility.

  14. Oxidation of propane with oxygen, nitrous oxide and oxygen/nitrous oxide mixture over Co- and Fe-zeolites

    Czech Academy of Sciences Publication Activity Database

    Novoveská, K.; Bulánek, R.; Wichterlová, Blanka

    2005-01-01

    Roč. 100, 3-4 (2005), s. 315-319 ISSN 0920-5861 R&D Projects: GA ČR(CZ) GA104/03/1120 Institutional research plan: CEZ:AV0Z40400503 Keywords : propene * propane oxidation * nitrous oxide * Fe-ZSM-5 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.365, year: 2005

  15. Nitrogen removal and intentional nitrous oxide production from reject water in a coupled nitritation/nitrous denitritation system under real feed-stream conditions.

    Science.gov (United States)

    Weißbach, Max; Thiel, Paul; Drewes, Jörg E; Koch, Konrad

    2018-05-01

    A Coupled Aerobic-anoxic Nitrous Decomposition Operation (CANDO) was performed over five months to investigate the performance and dynamics of nitrogen elimination and nitrous oxide production from digester reject water under real feed-stream conditions. A 93% conversion of ammonium to nitrite could be maintained for adapted seed sludge in the first stage (nitritation). The second stage (nitrous denitritation), inoculated with conventional activated sludge, achieved a conversion of 70% of nitrite to nitrous oxide after only 12 cycles of operation. The development of an alternative feeding strategy and the addition of a coagulant (FeCl 3 ) facilitated stable operation and process intensification. Under steady-state conditions, nitrite was reliably eliminated and different nitrous oxide harvesting strategies were assessed. Applying continuous removal increased N 2 O yields by 16% compared to the application of a dedicated stripping phase. These results demonstrate the feasible application of the CANDO process for nitrogen removal and energy recovery from ammonia rich wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Nitrous oxide pollution during x-ray exposure

    International Nuclear Information System (INIS)

    Yanagida, Hisashi; Nakajima, Michiaki.

    1980-01-01

    X-radiation has been shown to produce NO and NO 2 in the presence of nitrous oxide. The purpose of the present study was to confirm how much NO and NO 2 was produced when constant amount of nitrous oxide was exposed by constant X-radiation. Twenty polyethylene bottles (capacity 10 litres) were filled with nitrous oxide alone. Another 20 bottles were filled with nitrous oxide and 30% oxygen. Each bottle was placed at a distance of 30 cm from X-ray tube and they were directly in the line of the X-ray beam at a setting of 90 KV at 0.5 mA, a standard setting for chest fluoroscopy. The range of duration of X-ray exposure was from 0 (control), to 2, 3, and 5 minutes in 5 bottles each, respectively. A colorimetric recording method (Saltzman) and a chemiluminescent monitor were used for measurement of NO and NO 2 . In the bottles filled with nitrous oxide alone, the production of NO was not affected by the duration of X-ray exposure, but the longer duration of X-ray exposure produced a larger amount of NO 2 . In the bottles filled with nitrous oxide and 30% oxygen, the longer duration of X-ray exposure produced larger amounts of both NO and NO 2 . These findings confirmed a previous investigation in which nitrous oxide was not inert under X-ray exposure. As the presence of oxygen plays an important role in the oxidation of nitrous oxide under X-ray, this study suggests another potentially hazardous interaction that may occur secondary to the administration of anesthetic in the presence of X-irradiation such as pulmonary angiography, cardiac catheterization, and fluoroscopic bronchoscopy or biopsy under general anesthesia. (author)

  17. Complexation of Nitrous Oxide by Frustrated Lewis Pairs

    NARCIS (Netherlands)

    Otten, Edwin; Neu, Rebecca C.; Stephan, Douglas W.

    2009-01-01

    Frustrated Lewis pairs comprised of a basic yet sterically encumbered phosphine with boron Lewis acids bind nitrous oxide to give intact PNNOB linkages. The synthesis, structure, and bonding of these species are described.

  18. Carbon dioxide and nitrous oxide in the North Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; Naqvi, S.W.A; Jayakumar, D.A; George, M.D.; Narvekar, P.V.; DeSousa, S

    The understanding of biogeochemical cycling of carbon dioxide and nitrous oxide in the oceans is essential for predicting the fate of anthropogenically emitted components. The North Indian Ocean, with its diverse regimes, provides us with a natural...

  19. Control strategies for nitrous oxide emissions reduction on wastewater treatment plants operation.

    Science.gov (United States)

    Santín, I; Barbu, M; Pedret, C; Vilanova, R

    2017-11-15

    The present paper focused on reducing greenhouse gases emissions in wastewater treatment plants operation by application of suitable control strategies. Specifically, the objective is to reduce nitrous oxide emissions during the nitrification process. Incomplete nitrification in the aerobic tanks can lead to an accumulation of nitrite that triggers the nitrous oxide emissions. In order to avoid the peaks of nitrous oxide emissions, this paper proposes a cascade control configuration by manipulating the dissolved oxygen set-points in the aerobic tanks. This control strategy is combined with ammonia cascade control already applied in the literature. This is performed with the objective to take also into account effluent pollutants and operational costs. In addition, other greenhouse gases emissions sources are also evaluated. Results have been obtained by simulation, using a modified version of Benchmark Simulation Model no. 2, which takes into account greenhouse gases emissions. This is called Benchmark Simulation Model no. 2 Gas. The results show that the proposed control strategies are able to reduce by 29.86% of nitrous oxide emissions compared to the default control strategy, while maintaining a satisfactory trade-off between water quality and costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Field study of nitrous oxide production with in situ aeration in a closed landfill site.

    Science.gov (United States)

    Nag, Mitali; Shimaoka, Takayuki; Nakayama, Hirofumi; Komiya, Teppei; Xiaoli, Chai

    2016-03-01

    Nitrous oxide (N(2)O) has gained considerable attention as a contributor to global warming and depilation of stratospheric ozone layer. Landfill is one of the high emitters of greenhouse gas such as methane and N(2)O during the biodegradation of solid waste. Landfill aeration has been attracted increasing attention worldwide for fast, controlled and sustainable conversion of landfills into a biological stabilized condition, however landfill aeration impel N(2)O emission with ammonia removal. N(2)O originates from the biodegradation, or the combustion of nitrogen-containing solid waste during the microbial process of nitrification and denitrification. During these two processes, formation of N(2)O as a by-product from nitrification, or as an intermediate product of denitrification. In this study, air was injected into a closed landfill site and investigated the major N(2)O production factors and correlations established between them. The in-situ aeration experiment was carried out by three sets of gas collection pipes along with temperature probes were installed at three different distances of one, two and three meter away from the aeration point; named points A-C, respectively. Each set of pipes consisted of three different pipes at three different depths of 0.0, 0.75 and 1.5 m from the bottom of the cover soil. Landfill gases composition was monitored weekly and gas samples were collected for analysis of nitrous oxide concentrations. It was evaluated that temperatures within the range of 30-40°C with high oxygen content led to higher generation of nitrous oxide with high aeration rate. Lower O(2) content can infuse N(2)O production during nitrification and high O(2) inhibit denitrification which would affect N(2)O production. The findings provide insights concerning the production potentials of N(2)O in an aerated landfill that may help to minimize with appropriate control of the operational parameters and biological reactions of N turnover. Investigation of

  1. Enhancement of suggestibility and imaginative ability with nitrous oxide.

    Science.gov (United States)

    Whalley, M G; Brooks, G B

    2009-05-01

    Imaginative suggestibility, a trait closely related to hypnotic suggestibility, is modifiable under some circumstances. Nitrous oxide (laughing gas) is commonly used for sedation in dentistry and is reported to be more effective when combined with appropriate suggestions. The aim of this study was to determine whether nitrous oxide inhalation alters imaginative suggestibility and imagery vividness. Thirty participants were tested twice in a within-subjects design, once during inhalation of 25% nitrous oxide and once during inhalation of air plus oxygen. Before the study, participants' expectancies regarding the effects of nitrous oxide were assessed. Participants were blinded to drug administration. During each session, participants were verbally administered detailed measures of imagination and suggestibility: the Sheehan-Betts Quality of Mental Imagery scale and the Stanford Hypnotic Susceptibility Scale Form C, minus the hypnotic induction. Imaginative suggestibility and imaginative ability (imagery vividness) were both elevated in the nitrous oxide condition. This effect was unrelated to participants' expectations regarding the effects of the drug. Nitrous oxide increased imaginative suggestibility and imaginative ability. Possible explanations of these findings are discussed with respect to the effects of N-methyl-d-aspartate antagonists and to other pharmacological effects upon suggestibility and imagination.

  2. Archaea produce lower yields of N2 O than bacteria during aerobic ammonia oxidation in soil.

    Science.gov (United States)

    Hink, Linda; Nicol, Graeme W; Prosser, James I

    2017-12-01

    Nitrogen fertilisation of agricultural soil contributes significantly to emissions of the potent greenhouse gas nitrous oxide (N 2 O), which is generated during denitrification and, in oxic soils, mainly by ammonia oxidisers. Although laboratory cultures of ammonia oxidising bacteria (AOB) and archaea (AOA) produce N 2 O, their relative activities in soil are unknown. This work tested the hypothesis that AOB dominate ammonia oxidation and N 2 O production under conditions of high inorganic ammonia (NH 3 ) input, but result mainly from the activity of AOA when NH 3 is derived from mineralisation. 1-octyne, a recently discovered inhibitor of AOB, was used to distinguish N 2 O production resulting from archaeal and bacterial ammonia oxidation in soil microcosms, and specifically inhibited AOB growth, activity and N 2 O production. In unamended soils, ammonia oxidation and N 2 O production were lower and resulted mainly from ammonia oxidation by AOA. The AOA N 2 O yield relative to nitrite produced was half that of AOB, likely due to additional enzymatic mechanisms in the latter, but ammonia oxidation and N 2 O production were directly linked in all treatments. Relative contributions of AOA and AOB to N 2 O production, therefore, reflect their respective contributions to ammonia oxidation. These results suggest potential mitigation strategies for N 2 O emissions from fertilised agricultural soils. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  3. Life cycle assessment of selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator

    DEFF Research Database (Denmark)

    Møller, Jacob; Munk, Bjarne; Crillesen, Kim

    2011-01-01

    Selective non-catalytic reduction (SNCR) of nitrous oxides in a full-scale municipal solid waste incinerator was investigated using LCA. The relationship between NOx-cleaning and ammonia dosage was measured at the plant. Un-reacted ammonia – the ammonia slip – leaving the flue-gas cleaning system......-cleaning efficiency, the fate of the ammonia slip as well as the environmental impact from ammonia production, the potential acidification and nutrient enrichment from NOx-cleaning was calculated as a function of ammonia dosage. Since the exact fate of the ammonia slip could not be measured directly, a number...... of scenarios were set up ranging from “best case” with no ammonia from the slip ending up in the environment to “worst case” where all the ammonia slip eventually ended up in the environment and contributed to environmental pollution. In the “best case” scenario the highest ammonia dosage was most beneficial...

  4. Expansion of the acceptance program: nitrous oxide scavenging equipment and nitrous oxide trace gas monitoring equipment

    Energy Technology Data Exchange (ETDEWEB)

    1977-10-01

    The Acceptance Program for dental materials and devices and the general guidelines for submission of products have been reported in the Journal (88:615 March 1974). At its April 1977 meeting, the Council included equipment for scavenging and monitoring trace nitrous oxide gas in its Acceptance Program. The Council has established the effective date for classification of products under these two sets of guidelines as one year from the date of publication of this announcement. After that date, classification of a product will be required before promotion or exhibition in Association media.

  5. Nitrous Oxide Anesthesia and Plasma Homocysteine in Adolescents

    Science.gov (United States)

    Nagele, Peter; Tallchief, Danielle; Blood, Jane; Sharma, Anshuman; Kharasch, Evan D.

    2011-01-01

    Background Nitrous oxide inactivates vitamin B12, inhibits methionine synthase and consequently increases plasma total homocysteine (tHcy). Prolonged exposure to nitrous oxide can lead to neuropathy, spinal cord degeneration and even death in children. We tested the hypothesis that nitrous oxide anesthesia causes a significant increase in plasma tHcy in children. Methods Twenty-seven children (age 10-18 years) undergoing elective major spine surgery were enrolled and serial plasma samples from 0 – 96 hours after induction were obtained. The anesthetic regimen, including the use of nitrous oxide, was at the discretion of the anesthesiologist. Plasma tHcy was measured using standard enzymatic assays. Results The median baseline plasma tHcy concentration was 5.1 μmol/L (3.9 – 8.0 μmol/L, interquartile range) and increased in all patients exposed to nitrous oxide (n=26) by an average of +9.4 μmol/L (geometric mean; 95% CI 7.1 – 12.5 μmol/L) or +228% (mean; 95% CI 178% - 279%). Plasma tHcy peaked between 6-8 hours after induction of anesthesia. One patient who did not receive nitrous oxide had no increase in plasma tHcy. Several patients experienced a several-fold increase in plasma tHcy (max. +567%). The increase in plasma tHcy was strongly correlated with the duration and average concentration of nitrous oxide anesthesia (r= 0.80; pnitrous oxide anesthesia develop significantly increased plasma tHcy concentrations. The magnitude of this effect appears to be greater compared to adults; however, the clinical relevance is unknown. PMID:21680854

  6. Global oceanic production of nitrous oxide

    Science.gov (United States)

    Freing, Alina; Wallace, Douglas W. R.; Bange, Hermann W.

    2012-01-01

    We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N2O) to estimate the concentration of biologically produced N2O and N2O production rates in the ocean on a global scale. Our approach to estimate the N2O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N2O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N2O are not taken into account in our study. The largest amount of subsurface N2O is produced in the upper 500 m of the water column. The estimated global annual subsurface N2O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr−1. This is in agreement with estimates of the global N2O emissions to the atmosphere and indicates that a N2O source in the mixed layer is unlikely. The potential future development of the oceanic N2O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed. PMID:22451110

  7. Global oceanic production of nitrous oxide.

    Science.gov (United States)

    Freing, Alina; Wallace, Douglas W R; Bange, Hermann W

    2012-05-05

    We use transient time distributions calculated from tracer data together with in situ measurements of nitrous oxide (N(2)O) to estimate the concentration of biologically produced N(2)O and N(2)O production rates in the ocean on a global scale. Our approach to estimate the N(2)O production rates integrates the effects of potentially varying production and decomposition mechanisms along the transport path of a water mass. We estimate that the oceanic N(2)O production is dominated by nitrification with a contribution of only approximately 7 per cent by denitrification. This indicates that previously used approaches have overestimated the contribution by denitrification. Shelf areas may account for only a negligible fraction of the global production; however, estuarine sources and coastal upwelling of N(2)O are not taken into account in our study. The largest amount of subsurface N(2)O is produced in the upper 500 m of the water column. The estimated global annual subsurface N(2)O production ranges from 3.1 ± 0.9 to 3.4 ± 0.9 Tg N yr(-1). This is in agreement with estimates of the global N(2)O emissions to the atmosphere and indicates that a N(2)O source in the mixed layer is unlikely. The potential future development of the oceanic N(2)O source in view of the ongoing changes of the ocean environment (deoxygenation, warming, eutrophication and acidification) is discussed.

  8. Formation of methane and nitrous oxide in plants

    Science.gov (United States)

    Keppler, Frank; Lenhart, Katharina

    2017-04-01

    Methane, the second important anthropogenic greenhouse gas after carbon dioxide, is the most abundant reduced organic compound in the atmosphere and plays a central role in atmospheric chemistry. The global atmospheric methane budget is determined by many natural and anthropogenic terrestrial and aquatic surface sources, balanced primarily by one major sink (hydroxyl radicals) in the atmosphere. Natural sources of atmospheric methane in the biosphere have until recently been attributed to originate solely from strictly anaerobic microbial processes in wetland soils and rice paddies, the intestines of termites and ruminants, human and agricultural waste, and from biomass burning, fossil fuel mining and geological sources including mud volcanoes and seeps. However, recent studies suggested that terrestrial vegetation, fungi and mammals may also produce methane without the help of methanogens and under aerobic conditions (e.g. Keppler et al. 2009, Wang et al. 2013). These novel sources have been termed "aerobic methane production" to distinguish them from the well-known anaerobic methane production pathway. Nitrous oxide is another important greenhouse gas and major source of ozone-depleting nitric oxide. About two thirds of nitrous oxide emissions are considered to originate from anthropogenic and natural terrestrial sources, and are almost exclusively related to microbial processes in soils and sediments. However, the global nitrous oxide budget still has major uncertainties since it is unclear if all major sources have been identified but also the emission estimates of the know sources and stratospheric sink are afflicted with high uncertainties. Plants contribute, although not yet quantified, to nitrous oxide emissions either indirectly as conduits of soil derived nitrous oxide (Pihlatie et al. 2005), or directly via generation of nitrous oxide in leaves (Dean & Harper 1986) or on the leaf surface induced by UV irradiation (Bruhn et al. 2014). Moreover, lichens

  9. Sensitization of in vitro mammalian cells by nitrous oxide

    International Nuclear Information System (INIS)

    Ewing, D.

    1984-01-01

    Powers and his colleagues showed almost ten years ago that sensitization by nitrous oxide required two radiolytic products: OH radicals and hydrogen peroxide. That observation with bacterial spores has been confirmed and extended with spores and several strains of bacteria. OH must be present to form hydrogen peroxide, but, in addition, OH must also be present with the hydrogen peroxide for damage to occur. (Reagent hydrogen peroxide, except at very high concentrations, will not sensitize unless OH radicals are present.) The authors have now tested nitrous oxide with two Chinese hamster cell lines, V79 and CHO. The responses in nitrogen and nitrous oxide are the same for each. The authors have tentatively concluded that insufficient hydrogen peroxide is formed in the cells' suspending fluid for damage from nitrous oxide to occur. Several results support this conclusion: reagent hydrogen peroxide is a potent sensitizer of either cell line tested in nitrogen or nitrous oxide and an assay for radiolytic hydrogen peroxide confirms that only minimal levels are formed at the doses used in these survival curves. The authors also present results of other tests to further complement work with procaryotic cells

  10. Whippits, nitrous oxide and the dangers of legal highs.

    Science.gov (United States)

    Thompson, Alexander G; Leite, M Isabel; Lunn, Michael P; Bennett, David L H

    2015-06-01

    Nitrous oxide is increasingly being used as a recreational drug. Prolonged use of nitrous oxide can have disabling neurological sequelae due to functional inactivation of vitamin B₁₂. We present three cases illustrating the neurological complications of using nitrous oxide. Two of these patients received nitrous oxide as a consequence of repeated hospital attendance and the third via 'Whippit' canisters used in cream dispensers, which are now widely available. Two patients developed sensorimotor peripheral neuropathy with demyelinating features with no clinical or imaging evidence of myelopathy, emphasising that not all patients develop subacute combined degeneration of the spinal cord (the typical presentation of functional vitamin B12 deficiency). The diagnosis was based upon the history of nitrous oxide use and raised levels of homocysteine and/or methylmalonic acid. All patients were treated with parenteral vitamin B12 with partial recovery, though two were left significantly disabled. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Radiolysis of dodecane--tributylphosphate and nitrous oxide solutions

    International Nuclear Information System (INIS)

    Razvi, J.

    1978-01-01

    The chemical effects of 60 Co gamma irradiation on the nuclear fuel reprocessing solvents tributylphosphate (TBP) and dodecane were studied. Nitrous oxide, with concentrations in the range 20 mM to 140 mM, was used as the standard for competition kinetics. Solutions of TBP (with electron fractions of 0.025, 0.05, 0.1 and 0.3) in dodecane were irradiated. Primary gaseous products (non-condensible at 77K) in the radiolysis were nitrogen and hydrogen. Liquid products observed were the dimer, dodecanone, dodecanol, and fragmentation products C 5 -C 11 and C 17 -C 20 . Acid products from TBP were dibutylphosphate (DBP) and monobutylphosphate (MBP). All yields were determined both as a function of TBP and nitrous oxide concentrations. Kinetic analysis of nitrogen yields from dodecane--N 2 O radiolysis gave, G(total scavengable primary species) = 6.7 molecules/100 eV. Yields of dodecane liquid products could not be analyzed quantitatively due to the complex spectrum of products. In dodecane--N 2 O solutions, the dimer showed insignificant changes in yields and product distributions, indicating formation of additional dodecyl radicals in the presence of nitrous oxide. In dodecane--TBP mixtures, dimer yields reduced significantly as did the products from carbon--carbon bond cleavage. The addition of nitrous oxide to the binary mixture caused the dimer yield to increase, confirming formation of C 12 H 25 radicals by nitrous oxide reactions

  12. Heterotrophs are key contributors to nitrous oxide production in mixed liquor under low C-to-N ratios during nitrification - batch experiments and modelling

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Pellicer i Nàcher, Carles; Petersen, Morten S.

    2017-01-01

    Nitrous oxide (N2O), a by-product of biological nitrogen removal during wastewater treatment, is produced by ammonia-oxidizing bacteria (AOB) and heterotrophic denitrifying bacteria (HB). Mathematical models are used to predict N2O emissions, often including AOB as the main N2O producer. Several...

  13. Nitrous oxide emissions from open-lot cattle feedyards: A review

    Science.gov (United States)

    Nitrous oxide volatilization from concentrated animal feeding operations (CAFO), including cattle feedyards, has become an important research topic. However, there are limitations to current measurement techniques, uncertainty in the magnitude of feedyard nitrous oxide fluxes and a lack of effective...

  14. Nitrous oxide as an opioid agonist: some experimental and clinical applications

    International Nuclear Information System (INIS)

    Gillman, M.A.

    1984-01-01

    The interactions of nitrous oxide at analgesic concentrations with the endogenous opioid system is investigated, both in vitro and in vivo, with particular emphasis on the possibility that nitrous oxide is a possible tool both experimentally, diagnostically and therapeutically. In vitro findings show that nitrous oxide displaces ( 3 H) - naloxone from its binding sites in a definite and measurable manner, indicating a direct action of nitrous oxide at opioid receptors, in this case the mu site. An additional finding is that nitrous oxide unmasks a heretofore undiscovered super high affinity sites which may be an opioid auto-receptor. Naloxone was demonstrated to reverse acute alcoholic intoxication in some cases. The investigative as well as therapeutic role of nitrous oxide was investigated. It is concluded that nitrous oxide at analgesic concentrations (ie. low concentrations of nitrous oxide diluted with high concentrations of oxygen) is a safe and effective therapeutic agent

  15. Relationship between nitrogen cycling and nitrous oxide emission in grass-clover pasture

    OpenAIRE

    Ambus, P.

    2005-01-01

    The paper reports on a work assessing the relationship between gross N transformations in grass-clover soils and emissions of nitrous oxide. By this manner, the source strength of the biogenic processes responsible for nitrous oxide production is evaluated.

  16. Nitrous oxide reduction in nodules: denitrification or N2 fixation?

    International Nuclear Information System (INIS)

    Coyne, M.S.; Focht, D.D.

    1987-01-01

    Detached cowpea nodules that contained a nitrous oxide reductase-positive (Nor + ) rhizobium strain (8A55) and a nitrous oxide reductase-negative (Nor - ) rhizobium strain (32H1) were incubated with 1% 15 N 2 O (95 atom% 15 N) in the following three atmospheres: aerobic with C 2 H 2 (10%), aerobic without C 2 H 2 , and anaerobic (argon atmosphere) without C 2 H 2 . The greatest production of 15 N 2 occurred anaerobically with 8A55, yet very little was formed with 32H1. Although acetylene reduction activity was slightly higher with 32H1, about 10 times more 15 N 2 was produced aerobically by 8A55 than by 32H1 in the absence of acetylene. The major reductive pathway of N 2 O reduction by denitrifying rhizobium strain 8A55 is by nitrous oxide reductase rather than nitrogenase

  17. Crystallization of purple nitrous oxide reductase from Pseudomonas stutzeri

    International Nuclear Information System (INIS)

    Pomowski, Anja; Zumft, Walter G.; Kroneck, Peter M. H.; Einsle, Oliver

    2010-01-01

    The physiologically active form of nitrous oxide reductase was isolated and crystallized under strict exclusion of dioxygen and diffraction data were collected from crystals belonging to two different space groups. Nitrous oxide reductase (N 2 OR) from Pseudomonas stutzeri catalyzes the final step in denitrification: the two-electron reduction of nitrous oxide to molecular dinitrogen. Crystals of the enzyme were grown under strict exclusion of dioxygen by sitting-drop vapour diffusion using 2R,3R-butanediol as a cryoprotectant. N 2 OR crystallized in either space group P1 or P6 5 . Interestingly, the key determinant for the resulting space group was the crystallization temperature. Crystals belonging to space group P1 contained four 130 kDa dimers in the asymmetric unit, while crystals belonging to space group P6 5 contained a single dimer in the asymmetric unit. Diffraction data were collected to resolutions better than 2 Å

  18. A simple air sampling technique for monitoring nitrous oxide pollution

    Energy Technology Data Exchange (ETDEWEB)

    Austin, J C; Shaw, R; Moyes, D; Cleaton-Jones, P E

    1981-01-01

    A simple, inexpensive device for the continuous low-flow sampling of air was devised to permit monitoring of pollution by gaseous anaesthetics. The device consisted of a water-filled Perspex cylinder in which a double-walled flexible-film gas sample collection bag was suspended. Air samples could be aspirated into the collection bag at flow rates of as low as 1 ml min-1 by allowing the water to drain from the cylinder at a controlled rate. The maintenance of sample integrity with aspiration and storage of samples of nitrous oxide in air at concentrations of 1000, 100 and 30 p.p.m. v/v was examined using gas chromatography. The sample bags retained a mean 94% of the nitrous oxide in air samples containing nitrous oxide 25 p.p.m. over a 72-h storage period.

  19. Regional nitrous oxide flux in Amazon basin

    International Nuclear Information System (INIS)

    Felippe, Monica Tais Siqueira D'Amelio

    2010-01-01

    Nitrous oxide (N 2 O) is the third most important anthropogenic greenhouse gas. Globally, the main sources of N 2 O are nitrification and denitrification in soils. About two thirds of the soil emissions occur in the tropics and approximately 20% originate in wet rain forest ecosystems, like the Amazon forest. The work presented here involves aircraft vertical profiles of N 2 O from the surface to 4 km over two sites in the Eastern and Central Amazon: Tapajos National Forest (2000-2009) and Cuieiras Biologic Reserve (2004-2007), and the estimation of N 2 O fluxes for regions upwind of these sites using two methods: Column Integration Technique and Inversion Model - FLEXPART. To our knowledge, these regional scale N 2 O measurements in Amazonia are unique and represent a new approach to looking regional scale emissions. For the both methods, the fluxes upwind of Cuieiras Biologic Reserve exhibited little seasonality, and the annual mean was 1.9 ±1.6 mgN 2 Om -2 day -1 for the Column Integration Technique and 2.3±0.9 mgN 2 Om -2 day -1 for Inversion Model - FLEXPART. For fluxes upwind of Tapajos Nacional Forest, the Inversion Model - FLEXPART presented about half (0.9±1.7 mgN 2 Om -2 day -1 ) of the Column Integration Technique (2.0±1.1 mgN 2 Om -2 day -1 ) for the same period (2004-2008). One reason could be because the inversion model does not consider anthropic activities, once it had a good representation for less impacted area. Both regions presented similar emission during wet season. By Column Integration Technique, fluxes upwind Tapajos Nacional Forest were similar for dry and wet seasons. The dry season N 2 O fluxes exhibit significant correlations with CO fluxes, indicating a larger than expected source of N 2 O from biomass burning. The average CO:N 2 O ratio for all 38 profiles sampled during the dry season was 82±69 mol CO:molN 2 O and suggests a larger biomass burning contribution to the global N 2 O budget than previously reported. (author)

  20. Effects of dissolved oxygen and pH on nitrous oxide production rates in autotrophic partial nitrification granules.

    Science.gov (United States)

    Rathnayake, Rathnayake M L D; Oshiki, Mamoru; Ishii, Satoshi; Segawa, Takahiro; Satoh, Hisashi; Okabe, Satoshi

    2015-12-01

    The effects of dissolved oxygen (DO) and pH on nitrous oxide (N2O) production rates and pathways in autotrophic partial nitrification (PN) granules were investigated at the granular level. N2O was primarily produced by betaproteobacterial ammonia-oxidizing bacteria, mainly Nitrosomonas europaea, in the oxic surface layer (production increased with increasing bulk DO concentration owing to activation of the ammonia (i.e., hydroxylamine) oxidation in this layer. The highest N2O emissions were observed at pH 7.5, although the ammonia oxidation rate was unchanged between pH 6.5 and 8.5. Overall, the results of this study suggest that in situ analyses of PN granules are essential to gaining insight into N2O emission mechanisms in a granule. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Study on emission characteristics and reduction strategy of nitrous oxide during wastewater treatment by different processes.

    Science.gov (United States)

    Sun, Shichang; Bao, Zhiyuan; Sun, Dezhi

    2015-03-01

    Given the inexorable increase in global wastewater treatment, increasing amounts of nitrous oxide are expected to be emitted from wastewater treatment plants and released to the atmosphere. It has become imperative to study the emission and control of nitrous oxide in the various wastewater treatment processes currently in use. In the present investigation, the emission characteristics and the factors affecting the release of nitrous oxide were studied via full- and pilot-scale experiments in anoxic-oxic, sequencing batch reactor and oxidation ditch processes. We propose an optimal treatment process and relative strategy for nitrous oxide reduction. Our results show that both the bio-nitrifying and bio-denitrifying treatment units in wastewater treatment plants are the predominant sites for nitrous oxide production in each process, while the aerated treatment units are the critical sources for nitrous oxide emission. Compared with the emission of nitrous oxide from the anoxic-oxic (1.37% of N-influent) and sequencing batch reactor (2.69% of N-influent) processes, much less nitrous oxide (0.25% of N-influent) is emitted from the oxidation ditch process, which we determined as the optimal wastewater treatment process for nitrous oxide reduction, given the current technologies. Nitrous oxide emissions differed with various operating parameters. Controlling the dissolved oxygen concentration at a proper level during nitrification and denitrification and enhancing the utilization rate of organic carbon in the influent for denitrification are the two critical methods for nitrous oxide reduction in the various processes considered.

  2. Strategies to mitigate nitrous oxide emissions from herbivore production systems.

    Science.gov (United States)

    Schils, R L M; Eriksen, J; Ledgard, S F; Vellinga, Th V; Kuikman, P J; Luo, J; Petersen, S O; Velthof, G L

    2013-03-01

    Herbivores are a significant source of nitrous oxide (N(2)O) emissions. They account for a large share of manure-related N(2)O emissions, as well as soil-related N(2)O emissions through the use of grazing land, and land for feed and forage production. It is widely acknowledged that mitigation measures are necessary to avoid an increase in N(2)O emissions while meeting the growing global food demand. The production and emissions of N(2)O are closely linked to the efficiency of nitrogen (N) transfer between the major components of a livestock system, that is, animal, manure, soil and crop. Therefore, mitigation options in this paper have been structured along these N pathways. Mitigation technologies involving diet-based intervention include lowering the CP content or increasing the condensed tannin content of the diet. Animal-related mitigation options also include breeding for improved N conversion and high animal productivity. The main soil-based mitigation measures include efficient use of fertilizer and manure, including the use of nitrification inhibitors. In pasture-based systems with animal housing facilities, reducing grazing time is an effective option to reduce N(2)O losses. Crop-based options comprise breeding efforts for increased N-use efficiency and the use of pastures with N(2)-fixing clover. It is important to recognize that all N(2)O mitigation options affect the N and carbon cycles of livestock systems. Therefore, care should be taken that reductions in N(2)O emissions are not offset by unwanted increases in ammonia, methane or carbon dioxide emissions. Despite the abundant availability of mitigation options, implementation in practice is still lagging. Actual implementation will only follow after increased awareness among farmers and greenhouse gases targeted policies. So far, reductions in N(2)O emissions that have been achieved are mostly a positive side effect of other N-targeted policies.

  3. Direct methane and nitrous oxide emissions of monogastric livestock ...

    African Journals Online (AJOL)

    The Intergovernmental Panel on Climate Change (IPCC) methodology adapted to tropical production systems was used to calculate methane (CH4) and nitrous oxide (N2O) emissions. The non-ruminant sector is a minor GHG contributor compared with ruminant CH4 and N2O emissions. The pig industry and ostrich ...

  4. Municipal gravity sewers: an unrecognised source of nitrous oxide

    Science.gov (United States)

    Nitrous oxide (N2O) is a primary ozone-depleting substance and powerful greenhouse gas. N2O emissions from secondary-level wastewater treatment processes are relatively well understood as a result of intensive international research effort in recent times, yet little information...

  5. Nitrous oxide emissions affected by biochar and nitrogen stabilizers

    Science.gov (United States)

    Both biochar and N fertilizer stabilizers (N transformation inhibitors) are potential strategies to reduce nitrous oxide (N2O) emissions from fertilization, but the mechanisms and/or N transformation processes affecting the N dynamics are not fully understood. This research investigated N2O emission...

  6. Controls of nitrous oxide emission after simulated cattle urine deposition

    DEFF Research Database (Denmark)

    Baral, Khagendra Raj; Thomsen, Anton Gårde; Olesen, Jørgen E

    2014-01-01

    Urine deposited during grazing is a significant source of atmospheric nitrous oxide (N2O). The potential for N2O emissions from urine patches is high, and a better understanding of controls is needed. This study investigated soil nitrogen (N) dynamics and N2O emissions from cattle urine...

  7. Nitrous oxide emissions from the Gulf of Mexico Hypoxic Zone

    Science.gov (United States)

    The production of nitrous oxide (N2O), a potent greenhouse gas, in hypoxic coastal zones remains poorly characterized due to a lack of data, though large nitrogen inputs and deoxygenation typical of these systems create the potential for large N2O emissions. We report the first N...

  8. Nitrous oxide emission from denitrification in stream and river networks

    Science.gov (United States)

    Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification which converts N to N2O and dinitrog...

  9. Compilation of a global inventory of emissions of nitrous oxide

    NARCIS (Netherlands)

    Bouwman, A.F.

    1995-01-01

    A global inventory with 1°x1° resolution was compiled of emissions of nitrous oxide (N 2 O) to the atmosphere, including emissions from soils under natural vegetation, fertilized agricultural land, grasslands and animal excreta, biomass burning, forest clearing,

  10. Pitfalls in measuring nitrous oxide production by nitrifiers

    NARCIS (Netherlands)

    Wrage, N.

    2003-01-01

    Nitrous oxide (N 2 O) is an important greenhouse gas. At present, it causes 6% of global warming. The atmospheric concentration of N 2 O continues to increase at a rate of 0.8 ppb per year. The main known sink of N 2 O is its destruction in the stratosphere to

  11. Current and future nitrous oxide emissions from African agriculture

    NARCIS (Netherlands)

    Hickman, J.E.; Havlikova, M.; Kroeze, C.; Palm, C.A.

    2011-01-01

    Most emission estimates of the greenhouse gas nitrous oxide (N2O) from African agriculture at a continental scale are based on emission factors, such as those developed by the IPCC Guidelines. Here we present estimates from Africa from the EDGAR database, which is derived from the IPCC emission

  12. Controlling nitrous oxide emissions from grassland livestock production systems

    NARCIS (Netherlands)

    Oenema, O.; Gebauer, G.; Rodriguez, M.; Sapek, A.; Jarvis, S.C.; Corré, W.J.; Yamulki, S.

    1998-01-01

    There is growing awareness that grassland livestock production systems are major sources of nitrous oxide (N2O). Controlling these emissions requires a thorough understanding of all sources and controlling factors at the farm level. This paper examines the various controlling factors and proposes

  13. Nitrous oxide in the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.; Jayakumar, D; Nair, M.; DileepKumar, M.; George, M.D

    Extensive observations on nitrous oxide (N@d2@@O) in the atmosphere and waters of the western Bay of Bengal during March-April 1991 yield surface saturations and atmospheric fluxes ranging from 89.3 to 213.9% (mean 125.2%), and from 0.10 to 10...

  14. Measurement and reduction of nitrous oxide in operating rooms

    NARCIS (Netherlands)

    Schuyt, H. C.; Verberk, M. M.

    1996-01-01

    In a program designed to lower exposure to anesthetic gases, nitrous oxide in the breathing zone of anesthesiologists was continuously monitored by means of a direct reading apparatus and a specially designed collar. Initially, the average concentration during anesthesia in intubated patients,

  15. Nitrous oxide flux under changing temperature and CO2

    Science.gov (United States)

    We are investigating nitrous oxide flux seasonal trends and response to temperature and CO2 increases in a boreal peatland. Peatlands located in boreal regions make up a third of global wetland area and are expected to have the highest temperature increases in response to climat...

  16. Globally important nitrous oxide emissions from croplands induced by freeze-thaw cycles

    NARCIS (Netherlands)

    Wagner-Riddle, Claudia; Congreves, Katelyn A.; Abalos Rodriguez, Diego; Berg, Aaron A.; Brown, Shannon E.; Ambadan, Jaison Thomas; Gao, Xiaopeng; Tenuta, Mario

    2017-01-01

    Seasonal freezing induces large thaw emissions of nitrous oxide, a trace gas that contributes to stratospheric ozone destruction and atmospheric warming. Cropland soils are by far the largest anthropogenic source of nitrous oxide. However, the global contribution of seasonal freezing to nitrous

  17. Ammonia release method for depositing metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Silver, G.L.; Martin, F.S.

    1993-12-31

    A method of depositing metal oxides on substrates which is indifferent to the electrochemical properties of the substrates and which comprises forming ammine complexes containing metal ions and thereafter effecting removal of ammonia from the ammine complexes so as to permit slow precipitation and deposition of metal oxide on the substrates.

  18. Effects of different nitrogen forms, ammonia gas and wet deposited ammonium and nitrate, on methane and nitrous oxide emissions from an ombrotrophic bog, Whim Moss, in the Scottish Borders

    OpenAIRE

    Sheppard, L. J.; Leith, I. D.; Field, C.; van Dijk, N.; Rung, M.; Skiba, U.

    2008-01-01

    Enhanced reactive nitrogen deposition may compromise the sustainability and functioning of bogs, with respect to carbon sequestration and greenhouse gas production. Since 2002, three N forms have been applied to an ombrotrophic bog growing Calluna, Sphagnum capillifolium and Eriophorum vaginatum in order to test this. Significant changes in species cover and soil chemistry, especially in response to elevated ammonia concentrations, have been recorded. Ammonia deposition has also increased nit...

  19. Mitigation of hydrogen by oxidation using nitrous oxide and noble metal catalysts

    International Nuclear Information System (INIS)

    Britton, M.D.

    1995-01-01

    This test studied the ability of a blend of nuclear-grade, noble-metal catalysts to catalyze a hydrogen/nitrous oxide reaction in an effort to mitigate a potential hydrogen (H 2 ) gas buildup in the Hanford Site Grout Disposal Facility. For gases having H 2 and a stoichiometric excess of either nitrous oxide or oxygen, the catalyst blend can effectively catalyze the H 2 oxidation reaction at a rate exceeding 380 μmoles of H 2 per hour per gram of catalyst (μmol/h/g) and leave the gas with less than a 0.15 residual H 2 Concentration. This holds true in gases with up to 2.25% water vapor and 0.1% methane. This should also hold true for gases with up to 0.1% carbon monoxide (CO) but only until the catalyst is exposed to enough CO to block the catalytic sites and stop the reaction. Gases with ammonia up to 1% may be slightly inhibited but can have reaction rates greater than 250 μmol/h/g with less than a 0.20% residual H 2 concentration. The mechanism for CO poisoning of the catalyst is the chemisorption of CO to the active catalyst sites. The CO sorption capacity (SC) of the catalyst is the total amount of CO that the catalyst will chemisorb. The average SC for virgin catalyst was determined to be 19.3 ± 2.0 μmoles of CO chemisorbed to each gram of catalyst (μmol/g). The average SC for catalyst regenerated with air was 17.3 ± 1.9 μmol/g

  20. Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

    OpenAIRE

    Nakagawa, Tatsunori; Stahl, David A.

    2013-01-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

  1. Gross nitrous oxide production drives net nitrous oxide fluxes across a salt marsh landscape.

    Science.gov (United States)

    Yang, Wendy H; Silver, Whendee L

    2016-06-01

    Sea level rise will change inundation regimes in salt marshes, altering redox dynamics that control nitrification - a potential source of the potent greenhouse gas, nitrous oxide (N2 O) - and denitrification, a major nitrogen (N) loss pathway in coastal ecosystems and both a source and sink of N2 O. Measurements of net N2 O fluxes alone yield little insight into the different effects of redox conditions on N2 O production and consumption. We used in situ measurements of gross N2 O fluxes across a salt marsh elevation gradient to determine how soil N2 O emissions in coastal ecosystems may respond to future sea level rise. Soil redox declined as marsh elevation decreased, with lower soil nitrate and higher ferrous iron in the low marsh compared to the mid and high marshes (P production was highest in the low marsh and lowest in the mid-marsh (P = 0.02), whereas gross N2 O consumption did not differ among marsh zones. Thus, variability in gross N2 O production rates drove the differences in net N2 O flux among marsh zones. Our results suggest that future studies should focus on elucidating controls on the processes producing, rather than consuming, N2 O in salt marshes to improve our predictions of changes in net N2 O fluxes caused by future sea level rise. © 2015 John Wiley & Sons Ltd.

  2. Atmospheric nitrous oxide produced by solar protons and relativistic electrons

    International Nuclear Information System (INIS)

    Prasad, S.S.; Zipf, E.C.

    1981-01-01

    An alternative means of nitric oxide production in the stratosphere to that of direct formation in the upper atmosphere by solar proton (SP) events and by relativistic electron precipitation (REP) events from the Earth's radiation belt, is described. It is suggested that nitrous oxide is produced in the mesosphere and then migrates downward and is converted in the stratosphere to NO by the reaction N 2 O + O( 1 D) → 2 NO. Such a process could amplify the direct NO production by >10%. Mesospheric nitrous oxide mixing ratios increase to values as high as 6 x 10 -7 due to REP- and SP- related production. Lateral transport will reduce these high values but mesospheric mixing ratios of N 2 O in the high latitudes would approach 10 -7 , considerably greater than those expected on the basis of theories which neglect REP- and SP-related production of this species. (U.K.)

  3. Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

    Science.gov (United States)

    Stahl, David A.

    2013-01-01

    The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

  4. Extending the benchmark simulation model no2 with processes for nitrous oxide production and side-stream nitrogen removal

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Sin, Gürkan; Gernaey, Krist V.

    2015-01-01

    In this work the Benchmark Simulation Model No.2 is extended with processes for nitrous oxide production and for side-stream partial nitritation/Anammox (PN/A) treatment. For these extensions the Activated Sludge Model for Greenhouse gases No.1 was used to describe the main waterline, whereas...... the Complete Autotrophic Nitrogen Removal (CANR) model was used to describe the side-stream (PN/A) treatment. Comprehensive simulations were performed to assess the extended model. Steady-state simulation results revealed the following: (i) the implementation of a continuous CANR side-stream reactor has...... increased the total nitrogen removal by 10%; (ii) reduced the aeration demand by 16% compared to the base case, and (iii) the activity of ammonia-oxidizing bacteria is most influencing nitrous oxide emissions. The extended model provides a simulation platform to generate, test and compare novel control...

  5. Effects of ionization and nitrous oxide on grated carrot respiration

    International Nuclear Information System (INIS)

    Chervin, C.

    1992-06-01

    Two treatments (nitrous oxide and irradiation) have been applied on grated carrots to reduce the respiratory crisis induced by wounding. Nitrous oxide inhibited cytochrome c oxidase; but, it neither diminished O 2 consumption of the tissues, nor modified atmospheres in a favourable way for conservation of grated carrots, stored in plastic bags (in the conditions chosen for this study). On the contrary, irradiation inhibited simultaneously the respiratory crisis and the ethylene production, both induced by wounding. This behaviour led to a lower consumption of sugars in irradiated tissues and to the generation of atmospheres, which were better adapted to the conservation needs (it was necessary to use plastic film with high permeability). Finally, an applied study demonstrated that irradiation, by permitting a less denaturing preparation than industrial process, allowed the conservation of produces with a better quality (nutritional, sensory and microbiological). Biochemical analyses have been validated by sensory analyses

  6. Measurement system for nitrous oxide based on amperometric gas sensor

    Science.gov (United States)

    Siswoyo, S.; Persaud, K. C.; Phillips, V. R.; Sneath, R.

    2017-03-01

    It has been well known that nitrous oxide is an important greenhouse gas, so monitoring and control of its concentration and emission is very important. In this work a nitrous oxide measurement system has been developed consisting of an amperometric sensor and an appropriate lab-made potentiostat that capable measuring picoampere current ranges. The sensor was constructed using a gold microelectrode as working electrode surrounded by a silver wire as quasi reference electrode, with tetraethyl ammonium perchlorate and dimethylsulphoxide as supporting electrolyte and solvent respectively. The lab-made potentiostat was built incorporating a transimpedance amplifier capable of picoampere measurements. This also incorporated a microcontroller based data acquisition system, controlled by a host personal computer using a dedicated computer program. The system was capable of detecting N2O concentrations down to 0.07 % v/v.

  7. Diversity and abundance of ammonia-oxidizing

    NARCIS (Netherlands)

    Cardoso, J.F.M.F.; van Bleijswijk, J.D.L.; Witte, H.; van Duyl, F.C.

    2013-01-01

    We analysed the diversity and abundance of ammonia-oxidizing Archaea (AOA) and Bacteria (AOB) in the shallow warm-water sponge Halisarca caerulea and the deep cold-water sponges Higginsia thielei and Nodastrella nodastrella. The abundance of AOA and AOB was analysed using catalyzed reporter

  8. Fungal contribution to nitrous oxide emissions from cattle impacted soils

    Czech Academy of Sciences Publication Activity Database

    Jirout, Jiří; Šimek, Miloslav; Elhottová, Dana

    2013-01-01

    Roč. 90, č. 2 (2013), s. 565-572 ISSN 0045-6535 R&D Projects: GA ČR GPP504/12/P752; GA MŠk LC06066 Grant - others:GAJU(CZ) 04-142/2010/P Institutional research plan: CEZ:AV0Z60660521 Institutional support: RVO:60077344 Keywords : nitrous oxide * soil fungi * upland pasture * cattle * outdoor husbandry Subject RIV: EE - Microbiology, Virology Impact factor: 3.499, year: 2013

  9. Nitrous oxide emissions from the Arabian Sea: A synthesis

    Digital Repository Service at National Institute of Oceanography (India)

    Bange, H.W.; Andreae, M.O.; Lal, S.; Law, C.S.; Naqvi, S.W.A.; Patra, P.K.; Rixen, P.K.; Upstill-Goddard, R.C.

    ) seasonal and annual nitrous oxide (N2O) con- centration fields for the Arabian Sea surface layer using a database containing more than 2400 values measured be- tween December 1977 and July 1997. N2O concentrations are highest during the southwest (SW... is much more tightly constrained than the previous con- sensus derived using averaged in-situ data from a smaller number of studies. However, the tendency to focus on mea- surements in locally restricted features in combination with insufficient seasonal...

  10. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J; Koljonen, T [VTT Energy, Espoo (Finland)

    1997-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  11. Selective catalytic oxidation of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Leppaelahti, J.; Koljonen, T. [VTT Energy, Espoo (Finland)

    1996-12-31

    In the combustion of fossil fuels, the principal source of nitrogen oxides is nitrogen bound in the fuel structure. In gasification, a large part of fuel nitrogen forms NH{sub 3}, which may form nitrogen oxides during gas combustion. If NH{sub 3} and other nitrogen species could be removed from hot gas, the NO emission could be considerably reduced. However, relatively little attention has been paid to finding new means of removing nitrogen compounds from the hot gasification gas. The possibility of selectively oxidizing NH{sub 3} to N{sub 2} in the hot gasification has been studied at VTT Energy. The largest NH{sub 3} reductions have been achieved by catalytic oxidation on aluminium oxides. (author) (4 refs.)

  12. Urban sources and emissions of nitrous oxide and methane in southern California, USA

    Science.gov (United States)

    Townsend-Small, A.; Pataki, D.; Tyler, S. C.; Czimczik, C. I.; Xu, X.; Christensen, L. E.

    2012-12-01

    Anthropogenic activities have resulted in increasing levels of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. While global and regional emissions sources of carbon dioxide are relatively well understood, methane and nitrous oxide are less constrained, particularly at regional scales. Here we present the results of an investigation of sources and emissions of methane and nitrous oxide in Los Angeles, California, USA, one of Earth's largest urban areas. The original goal of the project was to determine whether isotopes are useful tracers of agricultural versus urban nitrous oxide and methane sources. For methane, we found that stable isotopes (carbon-13 and deuterium) and radiocarbon are good tracers of biogenic versus fossil fuel sources. High altitude observations of methane concentration, measured continuously using tunable laser spectroscopy, and isotope ratios, measured on discrete flask samples using mass spectrometry, indicate that the predominant methane source in Los Angeles is from fossil fuels, likely from "fugitive" emissions from geologic formations, natural gas pipelines, oil refining, or power plants. We also measured nitrous oxide emissions and isotope ratios from urban (landscaping and wastewater treatment) and agricultural sources (corn and vegetable fields). There was no difference in nitrous oxide isotope ratios between the different types of sources, although stable isotopes did differ between nitrous oxide produced in oxic and anoxic wastewater treatment tanks. Our nitrous oxide flux data indicate that landscaped turfgrass emits nitrous oxide at rates equivalent to agricultural systems, indicating that ornamental soils should not be disregarded in regional nitrous oxide budgets. However, we also showed that wastewater treatment is a much greater source of nitrous oxide than soils regionally. This work shows that global nitrous oxide and methane budgets are not easily downscaled to regional, urban settings, which has

  13. Health Hazard Evaluation Report HETA 84-204-1600, Dental Health Associates, Paoli, Pennsylvania. [Nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, M.S.

    1985-06-01

    Area air and breathing-zone samples were analyzed for nitrous oxide at Dental Health Associates, Paoli, Pennsylvania on August 2, 1984. The evaluation was requested by a dental assistant because of general concern about the extent of nitrous oxide exposure, especially since the office was not equipped with a waste-anesthetic gas-scavenging system. The author recommends installing a waste anesthetic gas scavenging system with a dedicated exhaust. The nitrous oxide delivery and mixing system should be checked for leaks monthly and work practices for handling nitrous oxide should be improved.

  14. Nitrous Oxide Production in a Granule-based Partial Nitritation Reactor: A Model-based Evaluation.

    Science.gov (United States)

    Peng, Lai; Sun, Jing; Liu, Yiwen; Dai, Xiaohu; Ni, Bing-Jie

    2017-04-03

    Sustainable wastewater treatment has been attracting increasing attentions over the past decades. However, the production of nitrous oxide (N 2 O), a potent GHG, from the energy-efficient granule-based autotrophic nitrogen removal is largely unknown. This study applied a previously established N 2 O model, which incorporated two N 2 O production pathways by ammonia-oxidizing bacteria (AOB) (AOB denitrification and the hydroxylamine (NH 2 OH) oxidation). The two-pathway model was used to describe N 2 O production from a granule-based partial nitritation (PN) reactor and provide insights into the N 2 O distribution inside granules. The model was evaluated by comparing simulation results with N 2 O monitoring profiles as well as isotopic measurement data from the PN reactor. The model demonstrated its good predictive ability against N 2 O dynamics and provided useful information about the shift of N 2 O production pathways inside granules for the first time. The simulation results indicated that the increase of oxygen concentration and granule size would significantly enhance N 2 O production. The results further revealed a linear relationship between N 2 O production and ammonia oxidation rate (AOR) (R 2  = 0.99) under the conditions of varying oxygen levels and granule diameters, suggesting that bulk oxygen and granule size may exert an indirect effect on N 2 O production by causing a change in AOR.

  15. Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged Y zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Sciyama, T; Arakawa, T; Matsuda, T; Yamazoe, N; Takita, Y

    1975-01-01

    The catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. The reaction products are nitrogen, nitrous oxide, and water in all cases. Selectivities to N/sub 2/ are 60 to 80% on all the cation exchanged zeolite catalysts exhibiting a relatively minor variation with the cationic species exchanged. The copper (II)-Y catalyst exhibits low temperature activity and has an unusual catalytic activity-temperature profile with a maximum at 120/sup 0/C. The catalytic activity is enhanced considerably when a second cation, especially cobalt (II) or iron (III) is coexchanged together with Cu (II) in Y zeolite.

  16. Effect of nutrient and selective inhibitor amendments on methane oxidation, nitrous oxide production, and key gene presence and expression in landfill cover soils: characterization of the role of methanotrophs, nitrifiers, and denitrifiers.

    Science.gov (United States)

    Lee, Sung-Woo; Im, Jeongdae; Dispirito, Alan A; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

    2009-11-01

    Methane and nitrous oxide are both potent greenhouse gasses, with global warming potentials approximately 25 and 298 times that of carbon dioxide. A matrix of soil microcosms was constructed with landfill cover soils collected from the King Highway Landfill in Kalamazoo, Michigan and exposed to geochemical parameters known to affect methane consumption by methanotrophs while also examining their impact on biogenic nitrous oxide production. It was found that relatively dry soils (5% moisture content) along with 15 mg NH (4) (+) (kg soil)(-1) and 0.1 mg phenylacetylene(kg soil)(-1) provided the greatest stimulation of methane oxidation while minimizing nitrous oxide production. Microarray analyses of pmoA showed that the methanotrophic community structure was dominated by Type II organisms, but Type I genera were more evident with the addition of ammonia. When phenylacetylene was added in conjunction with ammonia, the methanotrophic community structure was more similar to that observed in the presence of no amendments. PCR analyses showed the presence of amoA from both ammonia-oxidizing bacteria and archaea, and that the presence of key genes associated with these cells was reduced with the addition of phenylacetylene. Messenger RNA analyses found transcripts of pmoA, but not of mmoX, nirK, norB, or amoA from either ammonia-oxidizing bacteria or archaea. Pure culture analyses showed that methanotrophs could produce significant amounts of nitrous oxide, particularly when expressing the particulate methane monooxygenase (pMMO). Collectively, these data suggest that methanotrophs expressing pMMO played a role in nitrous oxide production in these microcosms.

  17. Exposure control practices for administering nitrous oxide: A survey of dentists, dental hygienists, and dental assistants.

    Science.gov (United States)

    Boiano, James M; Steege, Andrea L; Sweeney, Marie H

    2017-06-01

    Engineering, administrative, and work practice controls have been recommended for many years to minimize exposure to nitrous oxide during dental procedures. To better understand the extent to which these exposure controls are used, the NIOSH Health and Safety Practices Survey of Healthcare Workers was conducted among members of professional practice organizations representing dentists, dental hygienists and dental assistants. The anonymous, modular, web-based survey was completed by 284 dental professionals in private practice who administered nitrous oxide to adult and/or pediatric patients in the seven days prior to the survey. Use of primary engineering controls (i.e., nasal scavenging mask and/or local exhaust ventilation (LEV) near the patient's mouth) was nearly universal, reported by 93% and 96% of respondents who administered to adult (A) and pediatric (P) patients, respectively. However, adherence to other recommended precautionary practices were lacking to varying degrees, and were essentially no different among those administering nitrous oxide to adult or pediatric patients. Examples of work practices which increase exposure risk, expressed as percent of respondents, included: not checking nitrous oxide equipment for leaks (41% A; 48% P); starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (13% A; 12% P); and not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% A; 7% P). Absence of standard procedures to minimize worker exposure to nitrous oxide (13% of all respondents) and not being trained on safe handling and administration of nitrous oxide (3%) were examples of breaches of administrative controls which may also increase exposure risk. Successful management of nitrous oxide emissions should include properly fitted nasal scavenging masks, supplemental LEV (when nitrous oxide levels cannot be adequately controlled using nasal masks alone), adequate general ventilation, regular

  18. Kinetics of abiotic nitrous oxide production via oxidation of hydroxylamine by particulate metals in seawater

    Science.gov (United States)

    Cavazos, A. R.; Taillefert, M.; Glass, J. B.

    2016-12-01

    The oceans are a significant of nitrous oxide (N2O) to the atmosphere. Current models of global oceanic N2­O flux focus on microbial N2O cycling and often ignore abiotic reactions, such as the thermodynamically favorable oxidation of the nitrification intermediate hydroxylamine (NH2OH) by Mn(IV) or Fe(III). At circumneutral pH, NH2OH oxidation is more thermodynamically favorable via Mn(IV) than Fe(III) reduction. We characterized the kinetics of NH2OH oxidation in synthetic ocean water at pH 5.1-8.8 using microsensor electrodes to measure real-time N2O production. N2O production rates and yield were greater when NH2OH was oxidized by Mn(IV) than Fe(III). Accordingly, the reduction of Mn(IV) was first order with respect to NH2OH whereas the reduction of Fe(III) was zero order with respect to NH2OH. Interestingly, the order of the reaction with respect to Mn(IV) appears to be negative whereas the reaction is second order with respect to Fe(III). The inverse order with respect to Mn(IV) may be due to the aggregation of particles in seawater, which decreases their surface area and changes their reactivity. Finally, the reaction is first order with respect to protons with Fe(III) as the oxidant but zero order with Mn(IV). The stronger effect of the pH on the reaction with Fe(III) as the oxidant compared to Mn(IV) reflects the stoichiometry of these two reactions, as each mole of N2O produced by Fe(III) reduction consumes eight protons while each mole of N2O produced with Mn(IV) as the oxidant requires only four protons. Our data show that abiotic NH2OH oxidation by Mn(IV) or Fe(III) particles may represent a significant source of N2O in seawater. These findings suggest that abiotic N2O production in marine waters may be significant in areas of the oceans where particulate metals originating from aerosols, dust, or rivers may react with NH2OH released from ammonia-oxidizing microorganisms.

  19. Nitrous oxide production kinetics during nitrate reduction in river sediments.

    Science.gov (United States)

    Laverman, Anniet M; Garnier, Josette A; Mounier, Emmanuelle M; Roose-Amsaleg, Céline L

    2010-03-01

    A significant amount of nitrogen entering river basins is denitrified in riparian zones. The aim of this study was to evaluate the influence of nitrate and carbon concentrations on the kinetic parameters of nitrate reduction as well as nitrous oxide emissions in river sediments in a tributary of the Marne (the Seine basin, France). In order to determine these rates, we used flow-through reactors (FTRs) and slurry incubations; flow-through reactors allow determination of rates on intact sediment slices under controlled conditions compared to sediment homogenization in the often used slurry technique. Maximum nitrate reduction rates (R(m)) ranged between 3.0 and 7.1microg Ng(-1)h(-1), and affinity constant (K(m)) ranged from 7.4 to 30.7mg N-NO(3)(-)L(-1). These values were higher in slurry incubations with an R(m) of 37.9microg Ng(-1)h(-1) and a K(m) of 104mg N-NO(3)(-)L(-1). Nitrous oxide production rates did not follow Michaelis-Menten kinetics, and we deduced a rate constant with an average of 0.7 and 5.4ng Ng(-1)h(-1) for FTR and slurry experiments respectively. The addition of carbon (as acetate) showed that carbon was not limiting nitrate reduction rates in these sediments. Similar rates were obtained for FTR and slurries with carbon addition, confirming the hypothesis that homogenization increases rates due to release of and increasing access to carbon in slurries. Nitrous oxide production rates in FTR with carbon additions were low and represented less than 0.01% of the nitrate reduction rates and were even negligible in slurries. Maximum nitrate reduction rates revealed seasonality with high potential rates in fall and winter and low rates in late spring and summer. Under optimal conditions (anoxia, non-limiting nitrate and carbon), nitrous oxide emission rates were low, but significant (0.01% of the nitrate reduction rates). Copyright 2009 Elsevier Ltd. All rights reserved.

  20. Nitrous oxide emission from denitrification in stream and river networks

    OpenAIRE

    Beaulieu, Jake J.; Tank, Jennifer L.; Hamilton, Stephen K.; Wollheim, Wilfred M.; Hall, Robert O.; Mulholland, Patrick J.; Peterson, Bruce J.; Ashkenas, Linda R.; Cooper, Lee W.; Dahm, Clifford N.; Dodds, Walter K.; Grimm, Nancy B.; Johnson, Sherri L.; McDowell, William H.; Poole, Geoffrey C.

    2010-01-01

    Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The fraction of denitrified N that escapes as N2O rather than N2 (i.e., the N2O yield) is an important determinant of how much N2O is produced by river networks, but little is known about the N2O yield in flowi...

  1. Nitrous oxide: Saturation properties and the phase diagram

    International Nuclear Information System (INIS)

    Ferreira, A.G.M.; Lobo, L.Q.

    2009-01-01

    The experimental values of the coordinates of the triple point and of the critical point of nitrous oxide registered in the literature were assessed and those judged as most reliable have been selected. Empirical equations have been found for the vapour pressure, sublimation and fusion curves. The virial coefficients and saturation properties as functions of temperature along the equilibrium curves are described by reduced equations. They were used in arriving at the molar enthalpies at the triple point and the normal boiling temperature. Equations for the sublimation and fusion curves resulting from the exactly integrated Clapeyron equation compare favourably with the results from the empirical treatment and the experimental data.

  2. Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant.

    Science.gov (United States)

    Aboobakar, Amina; Cartmell, Elise; Stephenson, Tom; Jones, Mark; Vale, Peter; Dotro, Gabriela

    2013-02-01

    This paper reports findings from online, continuous monitoring of dissolved and gaseous nitrous oxide (N₂O), combined with dissolved oxygen (DO) and ammonia loading, in a full-scale nitrifying activated sludge plant. The study was conducted over eight weeks, at a 210,000 population equivalent sewage treatment works in the UK. Results showed diurnal variability in the gaseous and dissolved N₂O emissions, with hourly averages ranging from 0 to 0.00009 kgN₂O-N/h for dissolved and 0.00077-0.0027 kgN₂O-N/h for gaseous nitrous oxide emissions respectively, per ammonia loading, depending on the time of day. Similarly, the spatial variability was high, with the highest emissions recorded immediately after the anoxic zone and in the final pass of the aeration lane, where ammonia concentrations were typically below 0.5 mg/L. Emissions were shown to be negatively correlated to dissolved oxygen, which fluctuated between 0.5 and 2.5 mgO₂/L, at the control set point of 1.5 mgO₂/L. The resulting dynamic DO conditions are known to favour N₂O production, both by autotrophic and heterotrophic processes in mixed cultures. Average mass emissions from the lane were greater in the gaseous (0.036% of the influent total nitrogen) than in the dissolved (0.01% of the influent total nitrogen) phase, and followed the same diurnal and spatial patterns. Nitrous oxide emissions corresponded to over 34,000 carbon dioxide equivalents/year, adding 13% to the carbon footprint associated with the energy requirements of the monitored lane. A clearer understanding of emissions obtained from real-time data can help towards finding the right balance between improving operational efficiency and saving energy, without increasing N₂O emissions. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Emissions of nitrous oxide and methane from surface and ground waters in Germany

    International Nuclear Information System (INIS)

    Hiessl, H.

    1993-01-01

    The paper provides a first estimation of the contribution of inland freshwater systems (surface waters and ground waters) to the emission of the greenhouse gases nitrous oxide and methane in Germany. These amounts are compared to other main sources for the emission of nitrous oxide and methane. (orig.) [de

  4. How well do we understand nitrous oxide emissions from open-lot cattle systems?

    Science.gov (United States)

    Nitrous oxide is an important greenhouse gas that is produced in manure. Open lot beef cattle feedyards emit nitrous oxide but little information is available about exactly how much is produced. This has become an important research topic because of environmental concerns. Only a few methods are ava...

  5. Nitrogen management impacts nitrous oxide emissions under varying cotton irrigation systems in the American Desert Southwest

    Science.gov (United States)

    Irrigation of food and fiber crops worldwide continues to increase. Nitrogen (N) from fertilizers is a major source of the potent greenhouse gas nitrous oxide (N2O) in irrigated cropping systems. Nitrous oxide emissions data are scarce for crops in the arid Western US. The objective of these studies...

  6. Analysis of microbial populations, denitrification, and nitrous oxide production in riparian buffers

    Science.gov (United States)

    Riparian buffers are used extensively to protect water bodies from nonpoint source nitrogen pollution. However there is relatively little information on the impact of these buffers on production of nitrous oxide (N2O). In this study, we assessed nitrous oxide production in riparian buffers of the so...

  7. Nitrous oxide emissions from a coal mine land reclaimed with stabilized manure

    Science.gov (United States)

    Mined land restoration using manure-based amendments may create soil conditions suitable for nitrous oxide production and emission. We measured nitrous oxide emissions from mine soil amended with composted poultry manure (Comp) or poultry manure mixed with paper mill sludge (Man+PMS) at C/N ratios o...

  8. Manual on measurement of methane and nitrous oxide emissions from agriculture

    International Nuclear Information System (INIS)

    1992-11-01

    Nitrous oxide and methane are two of the gases primarily responsible for atmospheric warming, or the ''greenhouse effect''. Agricultural activities are an important source of methane and nitrous oxide emissions, but quantitation of these sources is generally lacking. This manual describes techniques to evaluate current emissions from diverse animal and crop production practices and suggests methods for decreasing these emissions. Refs, figs and tabs

  9. Rye cover crop effects on nitrous oxide emissions from a corn-soybean system

    Science.gov (United States)

    Agricultural activities are a major source nitrous oxide emitted to the atmosphere. Development of management practices to reduce these emissions is needed. Non-leguminous cover crops are efficient scavengers of residual soil nitrate, but their effects on nitrous oxide emissions have not been well d...

  10. Direct and indirect nitrous oxide emissions from agricultural soils, 1990 - 2003. Background document on the calculation method for the Dutch National Inventory Report

    International Nuclear Information System (INIS)

    Van der Hoek, K.W.; Van Schijndel, M.W.; Kuikman, P.J.

    2007-01-01

    Since 2005 the Dutch method to calculate the nitrous oxide emissions from agricultural soils has fully complied with the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidelines. In order to meet the commitments of the Convention on Climate Change and the Kyoto Protocol, nitrous oxide emissions have to be reported annually in the Dutch National Inventory Report (NIR). Countries are encouraged to use country-specific data rather than the default values provided by the IPCC. This report describes the calculation schemes and data sources used for nitrous oxide emissions from agricultural soils in the Netherlands. The nitrous oxide emissions, which contribute to the greenhouse effect, occur due to nitrification and denitrification processes. They include direct emissions from agricultural soils due to the application of animal manure and fertilizer nitrogen and the manure production in the meadow. Also included are indirect emissions resulting from the subsequent leaching of nitrate to ground water and surface waters, and from deposition of ammonia that had volatilized as a result of agricultural activities. Before 2005 indirect emissions in the Netherlands were calculated using a method that did not compare well with IPCC definitions and categories. The elaborate explanation here should facilitate reviewing by experts. Finally, the report also presents an overview of the nitrous oxide emissions from agricultural soils and the underlying data used in the 1990 - 2003 period

  11. Effects of nitrous oxide on the rat heart in vivo: another inhalational anesthetic that preconditions the heart?

    NARCIS (Netherlands)

    Weber, Nina C.; Toma, Octavian; Awan, Saqib; Frässdorf, Jan; Preckel, Benedikt; Schlack, Wolfgang

    2005-01-01

    BACKGROUND: For nitrous oxide, a preconditioning effect on the heart has yet not been investigated. This is important because nitrous oxide is commonly used in combination with volatile anesthetics, which are known to precondition the heart. The authors aimed to clarify (1) whether nitrous oxide

  12. Acute ST-Elevation Myocardial Infarction, a Unique Complication of Recreational Nitrous Oxide Use.

    Science.gov (United States)

    Indraratna, Praveen; Alexopoulos, Chris; Celermajer, David; Alford, Kevin

    2017-08-01

    A 28-year-old male was admitted to hospital with an acute ST-elevation myocardial infarction. This was in the context of recreational abuse of nitrous oxide. The prevalence of nitrous oxide use in Australia has not been formally quantified, however it is the second most commonly used recreational drug in the United Kingdom. Nitrous oxide has previously been shown to increase serum homocysteine levels. This patient was discovered to have an elevated homocysteine level at baseline, which was further increased after nitrous oxide consumption. Homocysteine has been linked to endothelial dysfunction and coronary atherosclerosis and this case report highlights one of the dangers of recreational abuse of nitrous oxide. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  13. The Neurotoxicity of Nitrous Oxide: The Facts and “Putative” Mechanisms

    Science.gov (United States)

    Savage, Sinead; Ma, Daqing

    2014-01-01

    Nitrous oxide is a widely used analgesic agent, used also in combination with anaesthetics during surgery. Recent research has raised concerns about possible neurotoxicity of nitrous oxide, particularly in the developing brain. Nitrous oxide is an N-methyl-d-aspartate (NMDA)-antagonist drug, similar in nature to ketamine, another anaesthetic agent. It has been linked to post-operative cardiovascular problems in clinical studies. It is also widely known that exposure to nitrous oxide during surgery results in elevated homocysteine levels in many patients, but very little work has investigated the long term effect of these increased homocysteine levels. Now research in rodent models has found that homocysteine can be linked to neuronal death and possibly even cognitive deficits. This review aims to examine the current knowledge of mechanisms of action of nitrous oxide, and to describe some pathways by which it may have neurotoxic effects. PMID:24961701

  14. Gaschromatographic proof of nitrous oxide concentrations in air by means of radiation ionization detectors

    International Nuclear Information System (INIS)

    Popp, P.; Schoentube, E.; Oppermann, G.

    1985-01-01

    For the analysis of nitrous oxide concentrations at workplaces in operating theatres, gaschromatography is a particularly suitable method if it is possible to measure nitrous oxide concentrations in the ppm to ppb region. For this, most frequently used gaschromatographic detectors (flame ionization detector, thermal conductivity detector) are unsuitable, whereas radiation ionization detectors can be used successfully. The investigations using detectors designed at the Central Institute for Isotopes and Radiation Research of the GDR Academy of Sciences showed that a high-temperature electron-capture detector (ECD), working at a temperatur of 250 0 C, enables the determination of traces of nitrous oxide with a detection limit of about 200 ppb, while the helium detector has a limit of 50 ppb of nitrous oxide in room air. Since the helium detector requires extremely pure carrier gas, the high-temperature ECD appears more suitable for analyzing nitrous oxide. (author)

  15. Portable nitrous oxide sensor for understanding agricultural and soil emissions

    Energy Technology Data Exchange (ETDEWEB)

    Stanton, Alan [Southwest Sciences, Inc., Santa Fe, NM (United States); Zondlo, Mark [Princeton Univ., NJ (United States); Gomez, Anthony [Southwest Sciences, Inc., Santa Fe, NM (United States); Pan, Da [Princeton Univ., NJ (United States)

    2017-02-27

    Nitrous oxide (N2O) is the third most important greenhouse gas (GHG,) with an atmospheric lifetime of ~114 years and a global warming impact ~300 times greater than that of carbon dioxide. The main cause of nitrous oxide’s atmospheric increase is anthropogenic emissions, and over 80% of the current global anthropogenic flux is related to agriculture, including associated land-use change. An accurate assessment of N2O emissions from agriculture is vital not only for understanding the global N2O balance and its impact on climate but also for designing crop systems with lower GHG emissions. Such assessments are currently hampered by the lack of instrumentation and methodologies to measure ecosystem-level fluxes at appropriate spatial and temporal scales. Southwest Sciences and Princeton University are developing and testing new open-path eddy covariance instrumentation for continuous and fast (10 Hz) measurement of nitrous oxide emissions. An important advance, now being implemented, is the use of new mid-infrared laser sources that enable the development of exceptionally low power (<10 W) compact instrumentation that can be used even in remote sites lacking in power. The instrumentation will transform the ability to measure and understand ecosystem-level nitrous oxide fluxes. The Phase II results included successful extended field testing of prototype flux instruments, based on quantum cascade lasers, in collaboration with Michigan State University. Results of these tests demonstrated a flux detection limit of 5 µg m-2 s-1 and showed excellent agreement and correlation with measurements using chamber techniques. Initial tests of an instrument using an interband cascade laser (ICL) were performed, verifying that an order of magnitude reduction in instrument power requirements can be realized. These results point toward future improvements and testing leading to introduction of a commercial open path instrument for N2O flux measurements that is truly portable and

  16. Nitrosospira sp. Govern Nitrous Oxide Emissions in a Tropical Soil Amended With Residues of Bioenergy Crop

    Directory of Open Access Journals (Sweden)

    Késia S. Lourenço

    2018-04-01

    Full Text Available Organic vinasse, a residue produced during bioethanol production, increases nitrous oxide (N2O emissions when applied with inorganic nitrogen (N fertilizer in soil. The present study investigated the role of the ammonia-oxidizing bacteria (AOB community on the N2O emissions in soils amended with organic vinasse (CV: concentrated and V: non-concentrated plus inorganic N fertilizer. Soil samples and N2O emissions were evaluated at 11, 19, and 45 days after fertilizer application, and the bacterial and archaea gene (amoA encoding the ammonia monooxygenase enzyme, bacterial denitrifier (nirK, nirS, and nosZ genes and total bacteria were quantified by real time PCR. We also employed a deep amoA amplicon sequencing approach to evaluate the effect of treatment on the community structure and diversity of the soil AOB community. Both vinasse types applied with inorganic N application increased the total N2O emissions and the abundance of AOB. Nitrosospira sp. was the dominant AOB in the soil and was correlated with N2O emissions. However, the diversity and the community structure of AOB did not change with vinasse and inorganic N fertilizer amendment. The results highlight the importance of residues and fertilizer management in sustainable agriculture and can be used as a reference and an input tool to determine good management practices for organic fertilization.

  17. Nitrous oxide for labor analgesia: Utilization and predictors of conversion to neuraxial analgesia.

    Science.gov (United States)

    Sutton, Caitlin D; Butwick, Alexander J; Riley, Edward T; Carvalho, Brendan

    2017-08-01

    We examined the characteristics of women who choose nitrous oxide for labor analgesia and identified factors that predict conversion from nitrous oxide to labor neuraxial analgesia. Retrospective descriptive study. Labor and Delivery Ward. 146 pregnant women who used nitrous oxide for analgesia during labor and delivery between September 2014 and September 2015. Chart review only. Demographic, obstetric, and intrapartum characteristics of women using nitrous oxide were examined. Multivariable logistic regression was performed to identify factors associated with conversion from nitrous oxide to neuraxial analgesia. Data are presented as n (%), median [IQR], adjusted relative risk (aRR), and 95% confidence intervals (CI) as appropriate. During the study period, 146 women used nitrous oxide for labor analgesia (accounting for 3% of the total deliveries). The majority (71.9%) of women who used nitrous oxide were nulliparous, and over half (51.9%) had expressed an initial preference for "nonmedical birth." The conversion rate to neuraxial blockade was 63.2%, compared to a concurrent institutional rate of 85.1% in women who did not use nitrous oxide. Factors associated with conversion from nitrous oxide to neuraxial blockade were labor induction (aRR=2.0, CI 1.2-3.3) and labor augmentation (aRR=1.7, CI 1.0-2.9). Only a small number of women opted to use nitrous oxide during labor, analgesia was minimal, and most converted to neuraxial analgesia. Women with induced and augmented labors should be counseled about the increased likelihood that they will convert to neuraxial analgesia. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Nitrous oxide-related postoperative nausea and vomiting depends on duration of exposure.

    Science.gov (United States)

    Peyton, Philip J; Wu, Christine Yx

    2014-05-01

    Inclusion of nitrous oxide in the gas mixture has been implicated in postoperative nausea and vomiting (PONV) in numerous studies. However, these studies have not examined whether duration of exposure was a significant covariate. This distinction might affect the future place of nitrous oxide in clinical practice. PubMed listed journals reporting trials in which patients randomized to a nitrous oxide or nitrous oxide-free anesthetic for surgery were included, where the incidence of PONV within the first 24 postoperative hours and mean duration of anesthesia was reported. Meta-regression of the log risk ratio for PONV with nitrous oxide (lnRR PONVN2O) versus duration was performed. Twenty-nine studies in 27 articles met the inclusion criteria, randomizing 10,317 patients. There was a significant relationship between lnRR PONVN2O and duration (r = 0.51, P = 0.002). Risk ratio PONV increased 20% per hour of nitrous oxide after 45 min. The number needed to treat to prevent PONV by avoiding nitrous oxide was 128, 23, and 9 where duration was less than 1, 1 to 2, and over 2 h, respectively. The risk ratio for the overall effect of nitrous oxide on PONV was 1.21 (CIs, 1.04-1.40); P = 0.014. This duration-related effect may be via disturbance of methionine and folate metabolism. No clinically significant effect of nitrous oxide on the risk of PONV exists under an hour of exposure. Nitrous oxide-related PONV should not be seen as an impediment to its use in minor or ambulatory surgery.

  19. Determinants of Nitrous Oxide Emission from Agricultural Drainage Waters

    International Nuclear Information System (INIS)

    Reay, D. S.; Edwards, A. C.; Smith, K. A.

    2004-01-01

    Emissions of the powerful greenhouse gas nitrous oxide (N 2 O) from agricultural drainage waters are poorly quantified and its determinants are not fully understood. Nitrous oxide formation in agricultural soils is known to increase in response to N fertiliser application, but the response of N 2 O in field drainage waters is unknown. This investigation combined an intensive study of the direct flux of N 2 O from the surface of a fertilised barley field with measurement of dissolved N 2 O and nitrate (NO 3 ) concentrations in the same field's drainage waters. Dissolved N 2 O in drainage waters showed a clear response to field N fertilisation, following an identical pattern to direct N 2 O flux from the field surface. The range in N 2 O concentrations between individual field drains sampled on the same day was large, indicating considerable spatial variability exists at the farm scale. A consistent pattern of very rapid outgassing of the dissolved N 2 O in open drainage ditches was accentuated at a weir, where increased turbulence led to a clear drop in dissolved N 2 O concentration. This study underlines the need for carefully planned sampling campaigns wherever whole farm or catchment N 2 O emission budgets are attempted. It adds weight to the argument for the downward revision of the IPCC emission factor (EF 5 -g) for NO 3 in drainage waters

  20. Determinants of nitrous oxide emission from agricultural drainage waters

    International Nuclear Information System (INIS)

    Reay, D. S.; Edwards, A. C.; Smith, K. A.

    2005-01-01

    Emissions of the powerful greenhouse gas nitrous oxide (N 2 O) from agricultural drainage waters are poorly quantified and its determinants are not fully understood. Nitrous oxide formation in agricultural soils is known to increase in response to N fertiliser application, but the response of N 2 O in field drainage waters is unknown. This investigation combined an intensive study of the direct flux of N 2 O from the surface of a fertilised barley field with measurement of dissolved N 2 O and nitrate (NO 3 ) concentrations in the same field's drainage waters. Dissolved N 2 O in drainage waters showed a clear response to field N fertilisation, following an identical pattern to direct N 2 O flux from the field surface. The range in N 2 O concentrations between individual field drains sampled on the same day was large, indicating considerable spatial variability exists at the farm scale. A consistent pattern of very rapid outgassing of the dissolved N 2 O in open drainage ditches was accentuated at a weir, where increased turbulence led to a clear drop in dissolved N 2 O concentration. This study underlines the need for carefully planned sampling campaigns wherever whole farm or catchment N 2 O emission budgets are attempted. It adds weight to the argument for the downward revision of the IPCC emission factor (EF 5 -g) for NO 3 in drainage waters

  1. Chemical dosimetry of linac electron pulse with nitrous oxide

    International Nuclear Information System (INIS)

    Nanba, Hideki; Shinsaka, Kyoji; Hatano, Yoshihiko; Yagi, Masuo; Shiokawa, Takanobu.

    1975-01-01

    Absorption dose, dose rate and the reproducibility of intensity in each pulse of the electron beam pulses from a Linac (42 MeV, 3μsec) have been determined by applying nitrous oxide chemical dosimetry, in order to obtain the fundamental data required for radiation chemistry researches with the Linac. Nitrous oxide is used as a chemical dosimeter because it is known that it decomposed through radiation ensures easy detection and the determination of quantity of the decomposed product, nitrogen, which is stable, and presents linear relationship between absorption dose and produced quantity over the wide dose-rate range. Irradiation cells used for the experiment were cylindrical ones made of hard molybdenum glass. Irradiated samples were fractionated with liquid nitrogen, and separated and determined with a gas chromatograph. Details on the experimental results and their examination are described at the end. They include absorption dose of 1x10 16 eV/g per pulse, dose rate of 3x10 21 eV/g, sec and intensity reproducibility of +- 20%. (Wakatsuki, Y.)

  2. Differentiation of nitrous oxide emission factors for agricultural soils

    International Nuclear Information System (INIS)

    Lesschen, Jan Peter; Velthof, Gerard L.; Vries, Wim de; Kros, Johannes

    2011-01-01

    Nitrous oxide (N 2 O) direct soil emissions from agriculture are often estimated using the default IPCC emission factor (EF) of 1%. However, a large variation in EFs exists due to differences in environment, crops and management. We developed an approach to determine N 2 O EFs that depend on N-input sources and environmental factors. The starting point of the method was a monitoring study in which an EF of 1% was found. The conditions of this experiment were set as the reference from which the effects of 16 sources of N input, three soil types, two land-use types and annual precipitation on the N 2 O EF were estimated. The derived EF inference scheme performed on average better than the default IPCC EF. The use of differentiated EFs, including different regional conditions, allows accounting for the effects of more mitigation measures and offers European countries a possibility to use a Tier 2 approach. - Highlights: → We developed an N 2 O emission factor inference scheme for agricultural soils. → This scheme accounts for different N-input sources and environmental conditions. → The derived EF inference scheme performed better than the default IPCC EF. → The use of differentiated EFs allows for better accounting of mitigation measures. - Emission factors for nitrous oxide from agricultural soils are derived as a function of N-input sources and environmental conditions on the basis of empirical information.

  3. Strategies for decreasing nitrous oxide emissions from agricultural sources

    Energy Technology Data Exchange (ETDEWEB)

    Oenema, O. [AB-DLO, Wageningen (Netherlands)

    1999-08-01

    Following the Kyoto Conference of 1997, declaring the urgency of implementing strategies for decreasing greenhouse gas emissions, there are several valid arguments to examine the opportunities for reducing nitrous oxide emissions from agriculture. This paper provides a review of the state-of-the-art of emission reduction, discusses two strategies for decreasing emissions and identifies various gaps in current knowledge in this field and the need for relevant scientific research. The two strategies discussed are (1) increasing the nitrogen use efficiency toward the goal of lowering total nitrogen input, and (2) decreasing the release of nitrous oxide per unit of nitrogen from the processes of nitrification and denitrification. Increasing nitrogen use efficiency is thought to be the most effective strategy. To that end, the paper discusses several practical actions and measures based on decisions at tactical and operational management levels. Knowledge gaps identified include (1) incomplete understanding of nitrogen cycling in farming systems, (2) incomplete quantitative understanding of emission controlling factors, (3) information gap between science and policy, and (4) information gap between science and practice. Appropriate research needs are suggested for each of these areas. It is suggested that the highest priority should be given to improving the understanding of emission controlling factors in the field and on the farm. 23 refs., 2 figs.

  4. Technical opportunities to reduce global anthropogenic emissions of nitrous oxide

    Science.gov (United States)

    Winiwarter, Wilfried; Höglund-Isaksson, Lena; Klimont, Zbigniew; Schöpp, Wolfgang; Amann, Markus

    2018-01-01

    We describe a consistent framework developed to quantify current and future anthropogenic emissions of nitrous oxide and the available technical abatement options by source sector for 172 regions globally. About 65% of the current emissions derive from agricultural soils, 8% from waste, and 4% from the chemical industry. Low-cost abatement options are available in industry, wastewater, and agriculture, where they are limited to large industrial farms. We estimate that by 2030, emissions can be reduced by about 6% ±2% applying abatement options at a cost lower than 10 €/t CO2-eq. The largest abatement potential at higher marginal costs is available from agricultural soils, employing precision fertilizer application technology as well as chemical treatment of fertilizers to suppress conversion processes in soil (nitrification inhibitors). At marginal costs of up to 100 €/t CO2-eq, about 18% ±6% of baseline emissions can be removed and when considering all available options, the global abatement potential increases to about 26% ±9%. Due to expected future increase in activities driving nitrous oxide emissions, the limited technical abatement potential available means that even at full implementation of reduction measures by 2030, global emissions can be at most stabilized at the pre-2010 level. In order to achieve deeper reductions in emissions, considerable technological development will be required as well as non-technical options like adjusting human diets towards moderate animal protein consumption.

  5. Adverse Cardiovascular Effects of Nitrous Oxide: It is not all about Hyperhomocysteinaemia

    Directory of Open Access Journals (Sweden)

    Ata Mahmoodpoor

    2015-04-01

    Full Text Available Once admired for its supposed safety, nitrous oxide is presently blamed to increase adverse cardiovascular effects through augmenting plasma homocysteine concentrations (1, 2. Hemodynamic alterations following the administration of nitrous oxide are extremely complicated and sometimes contradictory. Enhanced venous return, arterial pressure, pulmonary and systemic vascular resistance, cardiac output, pupillary dilation and diaphoresis occur under nitrous oxide administration consistent with sympathomimetic properties of nitrous oxide (3. Conversely, reductions in arterial pressure are also probable, especially in patients with coronary artery disease. Nitrous oxide can also depress myocardial contractility due to decreased availability of Ca2+ for contractile activation; yet, myocardial relaxation kinetics remains intact (4. In the presence of a volatile anesthetic, nitrous oxide decreases MVO2 (Myocardial oxygen consumption and myocardial O2 extraction which may exacerbate myocardial ischemia during concomitant reductions in arterial pressure in patients with coronary artery disease. Consequently, it could be conjectured that probable adverse cardiovascular effects following nitrous oxide administration are variable and consequent of a multi-variable phenomenon rather than a single variable such as increased levels of homocysteine. Studied purely focusing on the effects of nitrous oxide are difficult to conduct due to the numerous confounding factors. In a study by Myles et al., hyperhomocysteinemia has been introduced as the source of the adverse cardiovascular effects of nitrous oxide. However, in this study, increased inspired oxygen concentrations were used to overcome arterial desaturation (1. Given the fact that a constant volume and flow rates are used throughout the anesthesia in a particular patient, increasing the concentrations of oxygen would be associated with decreased delivered nitrous oxide and volatile anesthetic concentrations

  6. Nitrous oxide for the management of labor pain: a systematic review.

    Science.gov (United States)

    Likis, Frances E; Andrews, Jeffrey C; Collins, Michelle R; Lewis, Rashonda M; Seroogy, Jeffrey J; Starr, Sarah A; Walden, Rachel R; McPheeters, Melissa L

    2014-01-01

    We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management. We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate. We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited. The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

  7. Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Ma, Chun; Domingo-Felez, Carlos

    2017-01-01

    Nitrous oxide (N2O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N2O production were quantified in two lab-scale sequencing batch reactors...... to maintain high nitritation efficiency and high nitritation rates at 20-26 °C over a period of ∼300 days. Even at the high nitritation efficiencies, net N2O production was low (∼2% of the oxidized ammonium). Net N2O production rates transiently increased with a rise in pH after each feeding, suggesting...... operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted ∼93 ± 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient...

  8. NITROUS OXIDE EMISSIONS FROM SOUTHERN HIGH PLAINS BEEF CATTLE FEEDYARDS: MEASUREMENT AND MODELING

    Science.gov (United States)

    Predictive models for nitrous oxide emission are crucial for assessing the greenhouse gas footprint of beef cattle production. The Texas Panhandle produces approximately 42% of finished beef in the U.S. and cattle production is estimated to contribute 8 Tg carbon dioxide equivalents from nitrous oxi...

  9. Current use of nitrous oxide in public hospitals in Scandinavian countries.

    Science.gov (United States)

    Husum, B; Stenqvist, O; Alahuhta, S; Sigurdsson, G H; Dale, O

    2013-10-01

    The use of nitrous oxide in modern anaesthesia has been questioned. We surveyed changes in use of nitrous oxide in Scandinavia and its justifications during the last two decades. All 191 departments of anaesthesia in the Scandinavian countries were requested by email to answer an electronic survey in SurveyMonkey. One hundred and twenty-five (64%) of the departments responded; four were excluded. The 121 departments provided 807.520 general anaesthetics annually. The usage of nitrous oxide was reported in 11.9% of cases, ranging from 0.6% in Denmark to 38.6% in Iceland while volatile anaesthetics were employed in 48.9%, lowest in Denmark (22.6%) and highest in Iceland (91.9%). Nitrous oxide was co-administered with volatile anaesthetics in 21.5% of general anaesthetics [2.4% (Denmark) -34.5% (Iceland)]. Use of nitrous oxide was unchanged in five departments (4%), decreasing in 75 (62%) and stopped in 41 (34%). Reasons for decreasing or stopping use of nitrous oxide were fairly uniform in the five countries, the most important being that other agents were 'better', whereas few put weight on its potential risk for increasing morbidity. Decision to stop using nitrous oxide was made by the departments except in four cases. Of 87 maternity wards, nitrous oxide was used in 72, whereas this was the case in 42 of 111 day-surgery units. The use of nitrous oxide has decreased in the Scandinavian countries, apparently because many now prefer other agents. Difference in practices between the five countries were unexpected and apparently not justified on anticipated evidence only. © 2013 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. Effect of oxygen on decomposition of nitrous oxide over various metal oxide catalysts

    International Nuclear Information System (INIS)

    Satsuma, Atsushi; Maeshima, Hajime; Watanabe, Kiyoshi; Hattori, Tadashi

    2001-01-01

    The inhibitory effect of oxygen on decomposition of nitrous oxide over various metal oxide catalysts was investigated. The activity of nitrous oxide decomposition significantly decreased over CuO, Co 3 O 4 , NiO, Fe 2 O 3 , SnO 2 , In 2 O 3 and Cr 2 O 3 by reversible adsorption of oxygen onto the active sites. On the contrary to this, there was no or small change in the activity of TiO 2 , Al 2 O 3 , MgO, La 2 O 3 and CaO. A good correlation was observed between the degree of inhibition and the heat of formation of metal oxides. On the basis of kinetic model, the reduction of catalytic activity in the presence of oxygen was rationalized with the strength of oxygen adsorption on the metal oxide surface. (author)

  11. The electronic and optical properties of warm dense nitrous oxide using quantum molecular dynamics simulations

    International Nuclear Information System (INIS)

    Zhang Yujuan; Wang Cong; Zhang Ping

    2012-01-01

    First-principles molecular-dynamics simulations based on density-functional theory have been used to study the electronic and optical properties of fluid nitrous oxide under extreme conditions. Systematic descriptions of pair-correlation function, atomic structure, and the charge density distribution are used to investigate the dissociation of fluid nitrous oxide. The electrical and optical properties are derived from the Kubo-Greenwood formula. It is found that the nonmetal-metal transition for fluid nitrous oxide can be directly associated to the dissociation and has significant influence on the optical properties of the fluid.

  12. Removal of ammonia solutions used in catalytic wet oxidation processes.

    Science.gov (United States)

    Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

    2003-08-01

    Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

  13. Shell biofilm-associated nitrous oxide production in marine molluscs

    DEFF Research Database (Denmark)

    Heisterkamp, I.M.; Schramm, Andreas; Larsen, Lone Heimann

    2013-01-01

    Emission of the greenhouse gas nitrous oxide (N2O) from freshwater and terrestrial invertebrates has exclusively been ascribed to N2O production by ingested denitrifying bacteria in the anoxic gut of the animals. Our study of marine molluscs now shows that also microbial biofilms on shell surfaces...... are important sites of N2O production. The shell biofilms of Mytilus edulis, Littorina littorea and Hinia reticulata contributed 18-94% to the total animal-associated N2O emission. Nitrification and denitrification were equally important sources of N2O in shell biofilms as revealed by 15N-stable isotope...... mollusc species. Ammonium excretion by the animals was found to be sufficient to sustain N2O production in the shell biofilm. Apparently, the animals provide a nutrient-enriched microenvironment that stimulates growth and N2O production of the shell biofilm. This animal-induced stimulation...

  14. Sources of nitrous oxide emitted from European forest soils

    DEFF Research Database (Denmark)

    Ambus, P.; Zechmeister-Boltenstern, S.; Butterbach-Bahl, K.

    2006-01-01

    Forest ecosystems may provide strong sources of nitrous oxide (N2O), which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great...... uncertainties. In this study, we have investigated the quantitative and qualitative relationships between N-cycling and N2O production in European forests in order to evaluate the importance of nitrification and denitrification for N2O production. Soil samples were collected in 11 different sites characterized...... by variable climatic regimes and forest types. Soil N-cycling and associated production of N2O was assessed following application of 15N-labeled nitrogen. The N2O emission varied significantly among the different forest soils, and was inversely correlated to the soil C: N ratio. The N2O emissions were...

  15. Rapid nitrous oxide cycling in the suboxic ocean

    Science.gov (United States)

    Babbin, Andrew R.; Bianchi, Daniele; Jayakumar, Amal; Ward, Bess B.

    2015-06-01

    Nitrous oxide (N2O) is a powerful greenhouse gas and a major cause of stratospheric ozone depletion, yet its sources and sinks remain poorly quantified in the oceans. We used isotope tracers to directly measure N2O reduction rates in the eastern tropical North Pacific. Because of incomplete denitrification, N2O cycling rates are an order of magnitude higher than predicted by current models in suboxic regions, and the spatial distribution suggests strong dependence on both organic carbon and dissolved oxygen concentrations. Furthermore, N2O turnover is 20 times higher than the net atmospheric efflux. The rapid rate of this cycling coupled to an expected expansion of suboxic ocean waters implies future increases in N2O emissions.

  16. [Sedation with 50 % nitrous oxide/oxygen in paediatric dentistry].

    Science.gov (United States)

    Atash, R; Vanden Abbeele, A

    2008-09-01

    The management of paediatric dentistry treatment is essentially based on behaviour management but some behaviour troubles or mental retardation may hinder this kind of treatment at the dental office without any premedication. This often leads the dentist to change his treatment planning even if this may compromise the quality of treatment . Conscious sedation techniques enable stress and pain control during the active treatment phase and represent a useful alternative to general anaesthesia which cannot be used on a routine based level. Conscious sedation by the inhalation of nitrous oxide and oxygen (MEOPA) represents a good choice, as well as by its harmlessness as by its fast reversibility. MEOPA is a precious help in our practice, provided that its administration is totally under central and all contra-indication are respected. However sedation by inhalation should in no case be systematized and its goal must remain the progressive rehabilitation of the patient in a circuit of traditional ambulatory care.

  17. Fluxes of methane and nitrous oxide from an Indian mangrove

    Energy Technology Data Exchange (ETDEWEB)

    Krithika, K.; Purvaja, R.; Ramesh, R. [Anna Univ., Chennai (India). Institute for Ocean Management

    2008-01-25

    Methane and nitrous oxide are atmospheric trace gases and contribute about 15 and 6% respectively to the greenhouse effect. Both have a long atmospheric residence time of about 114 and 12 years respectively and since they are key compounds in the chemical reaction cycles of the troposphere and the stratosphere, their potential to directly or indirectly influence global climate is high. Fluxes of greenhouse gases, methane (CH{sub 4}) and nitrous oxide (N{sub 2}O), were measured from a mangrove ecosystem of the Cauvery delta (Muthupet) in South India. CH{sub 4} emissions were in the range between 18.99 and 37.53 mg/sq. m/d, with an average of 25.21 mg/sq. m/d, whereas N{sub 2}O emission ranged between 0.41 and 0.80 mg/sq. m/d (average of 0.62 mg/sq. m/d). The emission of CH{sub 4} and N{sub 2}O correlated positively with the number of pneumatophores. In addition to the flux measurements, different parts of the roots of Avicennia marina were quantified for CH{sub 4} concentration. Invariably in all the seasons, measured CH{sub 4} concentrations were high in the cable roots, with gradual decrease through the pneumatophores below water level and the above water level. This clearly indicates the transport of CH{sub 4} through the roots. We were able to establish that CH{sub 4} was released passively through the mangrove pneumatophores and is also a source to the atmosphere. We present some additional information on transport mechanisms of CH{sub 4} through the pneumatophores and bubble release from the mangrove ecosystems.

  18. Ammonia removal in electrochemical oxidation: Mechanism and pseudo-kinetics

    International Nuclear Information System (INIS)

    Li Liang; Liu Yan

    2009-01-01

    This paper investigated the mechanism and pseudo-kinetics for removal of ammonia by electrochemical oxidation with RuO 2 /Ti anode using batch tests. The results show that the ammonia oxidation rates resulted from direct oxidation at electrode-liquid interfaces of the anode by stepwise dehydrogenation, and from indirect oxidation by hydroxyl radicals were so slow that their contribution to ammonia removal was negligible under the condition with Cl - . The oxidation rates of ammonia ranged from 1.0 to 12.3 mg N L -1 h -1 and efficiency reached nearly 100%, primarily due to the indirect oxidation of HOCl, and followed pseudo zero-order kinetics in electrochemical oxidation with Cl - . About 88% ammonia was removed from the solution. The removed one was subsequently found in the form of N 2 in the produced gas. The rate at which Cl - lost electrons at the anode was a major factor in the overall ammonia oxidation. Current density and Cl - concentration affected the constant of the pseudo zero-order kinetics, expressed by k = 0.0024[Cl - ] x j. The ammonia was reduced to less than 0.5 mg N L -1 after 2 h of electrochemical oxidation for the effluent from aerobic or anaerobic reactors which treated municipal wastewater. This result was in line with the strict discharge requirements

  19. RESULTS OF INITIAL AMMONIA OXIDATION TESTING

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-12-30

    This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

  20. Denitrification: An important pathway for nitrous oxide production in tropical mangrove sediments (Goa, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; LokaBharathi, P.A.; Bonin, P.C.; Michotey, V.D.

    Net nitrous oxide production and denitrification activity were measured in two mangrove ecosystems of Goa, India. The relatively pristine site Tuvem was compared to Divar, which is prone to high nutrient input. Stratified sampling at 2-cm intervals...

  1. Data for "Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin"

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dissolved oxygen, dissolved nitrous oxide, and water temperature in reservoirs. This dataset is associated with the following publication: Beaulieu , J., C. Nietch ,...

  2. MLS/Aura Level 2 Nitrous Oxide (N2O) Mixing Ratio V004

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O is the EOS Aura Microwave Limb Sounder (MLS) standard product for nitrous oxide derived from radiances measured primarily by the 640 GHz radiometer (Band 12)...

  3. Effectiveness of Nitrous Oxide as a Liquid Injection Thrust Vector Control Fluid, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nitrous Oxide is proposed as an energetic liquid injection thrust vector control fluid for vehicle attitude control during dynamic vehicle maneuvers. Pulled from the...

  4. The influence of water vapor and sulfur dioxide on the catalytic decomposition of nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Yalamas, C.; Heinisch, R.; Barz, M. [Technische Univ. Berlin (Germany). Inst. fuer Energietechnik; Cournil, M. [Ecole Nationale Superieure des Mines, 42 - Saint-Etienne (France)

    2001-03-01

    For the nitrous oxide decomposition three groups of catalysts such as metals on support, hydrotalcites, and perovskites were studied relating to their activity in the presence of vapor or sulfur dioxide, in the temperature range from 200 to 500 C. It was found that the water vapor strongly inhibates the nitrous oxide decomposition at T=200-400 C. The sulfur dioxide poisons the catalysts, in particular the perovskites. (orig.)

  5. Nitrous Oxide for Treatment-Resistant Major Depression: A Proof-of-Concept Trial.

    Science.gov (United States)

    Nagele, Peter; Duma, Andreas; Kopec, Michael; Gebara, Marie Anne; Parsoei, Alireza; Walker, Marie; Janski, Alvin; Panagopoulos, Vassilis N; Cristancho, Pilar; Miller, J Philip; Zorumski, Charles F; Conway, Charles R

    2015-07-01

    N-methyl-D-aspartate receptor antagonists, such as ketamine, have rapid antidepressant effects in patients with treatment-resistant depression (TRD). We hypothesized that nitrous oxide, an inhalational general anesthetic and N-methyl-D-aspartate receptor antagonist, may also be a rapidly acting treatment for TRD. In this blinded, placebo-controlled crossover trial, 20 patients with TRD were randomly assigned to 1-hour inhalation of 50% nitrous oxide/50% oxygen or 50% nitrogen/50% oxygen (placebo control). The primary endpoint was the change on the 21-item Hamilton Depression Rating Scale (HDRS-21) 24 hours after treatment. Mean duration of nitrous oxide treatment was 55.6 ± 2.5 (SD) min at a median inspiratory concentration of 44% (interquartile range, 37%-45%). In two patients, nitrous oxide treatment was briefly interrupted, and the treatment was discontinued in three patients. Depressive symptoms improved significantly at 2 hours and 24 hours after receiving nitrous oxide compared with placebo (mean HDRS-21 difference at 2 hours, -4.8 points, 95% confidence interval [CI], -1.8 to -7.8 points, p = .002; at 24 hours, -5.5 points, 95% CI, -2.5 to -8.5 points, p nitrous oxide and placebo, p nitrous oxide compared with one patient (5%) and none after placebo (odds ratio for response, 4.0, 95% CI, .45-35.79; OR for remission, 3.0, 95% CI, .31-28.8). No serious adverse events occurred; all adverse events were brief and of mild to moderate severity. This proof-of-concept trial demonstrated that nitrous oxide has rapid and marked antidepressant effects in patients with TRD. Copyright © 2015 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  6. Effect of nitrous oxide on cisatracurium infusion demands: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Illman Hanna L

    2010-08-01

    Full Text Available Abstract Background Recent studies have questioned our previous understanding on the effect of nitrous oxide on muscle relaxants, since nitrous oxide has been shown to potentiate the action of bolus doses of mivacurium, rocuronium and vecuronium. This study was aimed to investigate the possible effect of nitrous oxide on the infusion requirements of cisatracurium. Methods 70 ASA physical status I-III patients aged 18-75 years were enrolled in this randomized trial. The patients were undergoing elective surgery requiring general anesthesia with a duration of at least 90 minutes. Patients were randomized to receive propofol and remifentanil by target controlled infusion in combination with either a mixture of oxygen and nitrous oxide (Nitrous oxide/TIVA group or oxygen in air (Air/TIVA group. A 0.1 mg/kg initial bolus of cisatracurium was administered before tracheal intubation, followed by a closed-loop computer controlled infusion of cisatracurium to produce and maintain a 90% neuromuscular block. Cumulative dose requirements of cisatracurium during the 90-min study period after bolus administration were measured and the asymptotic steady state rate of infusion to produce a constant 90% block was determined by applying nonlinear curve fitting to the data on the cumulative dose requirement during the study period. Results Controller performance, i.e. the ability of the controller to maintain neuromuscular block constant at the setpoint and patient characteristics were similar in both groups. The administration of nitrous oxide did not affect cisatracurium infusion requirements. The mean steady-state rates of infusion were 0.072 +/- 0.018 and 0.066 +/- 0.017 mg * kg-1 * h-1 in Air/TIVA and Nitrous oxide/TIVA groups, respectively. Conclusions Nitrous oxide does not affect the infusion requirements of cisatracurium. Trial registration ClinicalTrials.gov NCT01152905; European Clinical Trials Database at http://eudract.emea.eu.int/2006-006037-41.

  7. Influence of nitrous oxide anesthesia, B-vitamins, and MTHFR gene polymorphisms on perioperative cardiac events: the vitamins in nitrous oxide (VINO) randomized trial.

    Science.gov (United States)

    Nagele, Peter; Brown, Frank; Francis, Amber; Scott, Mitchell G; Gage, Brian F; Miller, J Philip

    2013-07-01

    Nitrous oxide causes an acute increase in plasma homocysteine that is more pronounced in patients with the methylenetetrahydrofolate reductase (MTHFR) C677T or A1298C gene variant. In this randomized controlled trial, the authors sought to determine whether patients carrying the MTHFR C677T or A1298C variant had a higher risk for perioperative cardiac events after nitrous oxide anesthesia and whether this risk could be mitigated by B-vitamins. The authors randomized adult patients with cardiac risk factors undergoing noncardiac surgery, to receive nitrous oxide plus intravenous B-vitamins before and after surgery, or to nitrous oxide and placebo. Serial cardiac biomarkers and 12-lead electrocardiograms were obtained. The primary study endpoint was the incidence of myocardial injury, as defined by cardiac troponin I increase within the first 72 h after surgery. A total of 500 patients completed the trial. Patients who were homozygous for either MTHFR C677T, or A1298C gene variant (n=98; 19.6%) had no increased rate of postoperative cardiac troponin I increase compared with wild-type and heterozygous patients (11.2 vs. 14.0%; relative risk 0.96; 95% CI, 0.85-1.07; P=0.48). B-vitamins blunted the rise in homocysteine, but had no effect on cardiac troponin I increase compared with patients receiving placebo (13.2 vs. 13.6%; relative risk 1.02; 95% CI 0.78 to 1.32; P=0.91). Neither MTHFR C677T and A1298C gene variant, nor acute homocysteine increase are associated with perioperative cardiac troponin increase after nitrous oxide anesthesia. B-vitamins blunt nitrous oxide-induced homocysteine increase but have no effect on cardiac troponin I increase.

  8. Relationship between respiratory quotient, nitrification, and nitrous oxide emissions in a forced aerated composting process

    Energy Technology Data Exchange (ETDEWEB)

    Tsutsui, Hirofumi, E-mail: jm-tsutsuih@kochi-u.ac.jp [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Fujiwara, Taku [Research and Education Faculty, Natural Sciences Cluster, Agriculture Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Inoue, Daisuke [Department of Health Science, School of Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara-Minami, Kanagawa (Japan); Japan Science and Technology Agency, CREST (Japan); Ito, Ryusei [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan); Matsukawa, Kazutsugu [Research and Education Faculty, Multidisciplinary Science Cluster, Life and Environmental Medicine Science Unit, Kochi University, B200 Monobe, Nankoku, Kochi (Japan); Japan Science and Technology Agency, CREST (Japan); Funamizu, Naoyuki [Department of Environmental Engineering, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo, Hokkaido (Japan); Japan Science and Technology Agency, CREST (Japan)

    2015-08-15

    Highlights: • RQ can be an indicator of N{sub 2}O emission in forced aerated composting process. • Emission of N{sub 2}O with nitrification was observed with RQ decrease. • Mass balances demonstrated the RQ decrease was caused by nitrification. • Conversion ratio of oxidized ammonia and total N to N{sub 2}O were ∼2.7%. - Abstract: We assessed the relationship between respiratory quotient (RQ) and nitrification and nitrous oxide (N{sub 2}O) emission in forced aerated composting using lab-scale reactors. Relatively high RQ values from degradation of readily degradable organics initially occurred. RQ then stabilized at slightly lower values, then decreased. Continuous emission of N{sub 2}O was observed during the RQ decrease. Correlation between nitrification and N{sub 2}O emission shows that the latter was triggered by nitrification. Mass balances demonstrated that the O{sub 2} consumption of nitrification (∼24.8 mmol) was slightly higher than that of CO{sub 2} emission (∼20.0 mmol), indicating that the RQ decrease was caused by the occurrence of nitrification. Results indicate that RQ is a useful index, which not only reflects the bioavailability of organics but also predicts the occurrence of nitrification and N{sub 2}O emission in forced aerated composting.

  9. Nitrous oxide emission from polyculture constructed wetlands: Effect of plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanhua [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China); Inamori, Ryuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kong Hainan [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China)], E-mail: remanda@126.com; Xu Kaiqin [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan Unviversity, Wuhan 430072 (China); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kondo, Takashi [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); Zhang Jixiang [School of Economics and Management, Southeast University, Nanjing, Jiangsu 210096 (China)

    2008-03-15

    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N{sub 2}O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N{sub 2}O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N{sub 2}O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N{sub 2}O m{sup -2} d{sup -1}. The highest N{sub 2}O emission occurred in the cell planted with Phragmites australis and Zizania latifolia. Whereas, the lower emission rate were obtained in the cell planted with P. australis and Typha latifolia. These revealed that Z. latifolia stimulated the N{sub 2}O emission. Transportation of more organic matter and oxygen for AOB growth may be the reason. The study of AOB also supported this result, indicating that the root structure of Z. latifolia was favored by AOB for N{sub 2}O formation. - Zizania latifolia has a large contribution to global warming.

  10. Rate for energy transfer from excited cyclohexane to nitrous oxide in the liquid phase

    International Nuclear Information System (INIS)

    Wada, T.; Hatano, Y.

    1975-01-01

    Pure liquid cyclohexane and cyclohexane solutions of nitrous oxide have been photolyzed at 163 nm. The quantum yield of the product hydrogen in the photolysis of pure cyclohexane is found to be 1.0. The addition of nitrous oxide results in the reduction in the yield of hydrogen and in the formation of nitrogen. The decrement of the hydrogen yield is approximately equal to the increment of the nitrogen yield. About 40 percent of the hydrogen yield in pure cyclohexane is found to be produced through a path which is not affected by the addition of nitrous oxide. The effect of the addition of nitrous oxide is attributed to energy transfer from excited cyclohexane to nitrous oxide with the rate constant of k = 1.0 x 10 11 M -1 sec -1 (at 15 0 C). This value is about a factor of 10 larger than that expected as for diffusion-controlled rate. A contribution of the energy transfer process to the formation of nitrogen in the radiolysis of cyclohexane solutions of nitrous oxide has also been discussed. (auth)

  11. Effect of Free Ammonia, Free Nitrous Acid, and Alkalinity on the Partial Nitrification of Pretreated Pig Slurry, Using an Alternating Oxic/Anoxic SBR

    Directory of Open Access Journals (Sweden)

    Marisol Belmonte

    2017-01-01

    Full Text Available The effect of free ammonia (NH3 or FA, free nitrous acid (HNO2 or FNA, and total alkalinity (TA on the performance of a partial nitrification (PN sequencing batch reactor (SBR treating anaerobically pretreated pig slurry was studied. The SBR was operated under alternating oxic/anoxic (O/A conditions and was fed during anoxic phases. This strategy allowed using organic matter to partially remove nitrite (NO2- and nitrate (NO3- generated during oxic phases. The desired NH4+ to NO2- ratio of 1.3 g N/g N was obtained when an Ammonium Loading Rate (ALR of 0.09 g NH4+-N/L·d was applied. The system was operated at a solid retention time (SRT of 15–20 d and dissolved oxygen (DO levels higher than 3 mg O2/L during the whole operational period. PN mainly occurred caused by the inhibitory effect of FNA on nitrite oxidizing bacteria (NOB. Once HNO2 concentration was negligible, NH4+ was fully oxidized to NO3- in spite of the presence of FA. The use of biomass acclimated to ammonium as inoculum avoided a possible effect of FA on NOB activity.

  12. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    OpenAIRE

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous oxide production at oxic conditions, but strongly enhanced the nitrous oxide production at oxygen-poor and anoxic conditions. Inhibition of nitrification by short exposure (1 to 24 h) to high conce...

  13. Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

    Science.gov (United States)

    Martens-Habbena, Willm; Stahl, David A

    2011-01-01

    The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Nitrous oxide emissions from clover in the Mediterranean environment

    Directory of Open Access Journals (Sweden)

    Iride Volpi

    2016-06-01

    Full Text Available Introducing nitrogen N2-fixing crops into cereal-based crop rotations reduces N-fertiliser use and may mitigate soil emissions of nitrous oxide (N2O. However, the effect of the cultivation of N2-fixing crops on N2O emissions is still not well understood. N2O from N2-fixing crops can be emitted in two ways: during biological N2 fixation itself and when legume residues are returned to the soil. A field trial was carried out on clover (Trifolium squarrosum Savi to test the role of leguminous crops on N2O emissions in the Mediterranean environment. Monitoring was performed from December 2013 to September 2014. Cumulated N-N2O fluxes were calculated for the growing season (Phase 1 and the post-harvest period (Phase 2 in order to assess the importance of each phase. Our results did not show statistically significant differences between the two phases in term of contribution to the total cumulative N-N2O emissions, in fact Phase 1 and Phase 2 accounted respectively for 43 and 57% of the total.

  15. Nitrous oxide (N2O) emission from aquaculture: a review.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Khanal, Samir Kumar

    2012-06-19

    Nitrous oxide (N(2)O) is an important greenhouse gas (GHG) which has a global warming potential 310 times that of carbon dioxide (CO(2)) over a hundred year lifespan. N(2)O is generated during microbial nitrification and denitrification, which are common in aquaculture systems. To date, few studies have been conducted to quantify N(2)O emission from aquaculture. Additionally, very little is known with respect to the microbial pathways through which N(2)O is formed in aquaculture systems. This review suggests that aquaculture can be an important anthropogenic source of N(2)O emission. The global N(2)O-N emission from aquaculture in 2009 is estimated to be 9.30 × 10(10) g, and will increase to 3.83 × 10(11)g which could account for 5.72% of anthropogenic N(2)O-N emission by 2030 if the aquaculture industry continues to increase at the present annual growth rate (about 7.10%). The possible mechanisms and various factors affecting N(2)O production are summarized, and two possible methods to minimize N(2)O emission, namely aquaponic and biofloc technology aquaculture, are also discussed. The paper concludes with future research directions.

  16. Nitrous oxide emission from agricultural lands in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Romanovskaya, A.A.; Gytarsky, M.L.; Karaban, R.T.; Nazarov, I.M. [Institute of Global Climate and Ecology, 20B, Glebovskaya Str., Moscow 107258 (Russian Federation); Konushkov, D.E. [Dokuchaev Soil Science Institute, 7, Pyzhevsky per., Moscow 109017 (Russian Federation)

    2002-07-01

    Nitrous oxide (N2O) atmospheric emission from different agricultural soil types in Russia was evaluated based on published data on single input of nitrogen (N) fertilizers. For most of experiments the rates of fertilization varied from 40 to 75 and from 160 to 264 kg/ha in active matter and they were considered separately. The higher rates of synthetic fertilizers (160 to 264 kg/ha) reduced relative gaseous loss of N as N2O (N2O-N). Evidently, if nitrate (NO3) concentrations were high, the low content of organic carbon (C) and oxygen (O) restricted soil microbiological activity and consequently formation of N2O. The majority of gaseous loss of N2O-N occurred within 140 days after the input of fertilizers. The N2O emission factors derived for chernozem and soddy podzolic soil are 0.0126 and 0.0238 kg N2O-N/kg N respectively. In 1990, the use of N fertilizers in national agriculture caused the release of 53 Gg N2O-N that constituted 6% of global N2O emission. Later on, the emission dropped because of decreased use of N fertilizers, and in 1998 it was almost 21% of the 1990 level.

  17. Nitrous oxide emission from agricultural lands in Russia

    International Nuclear Information System (INIS)

    Romanovskaya, A.A.; Gytarsky, M.L.; Karaban, R.T.; Nazarov, I.M.; Konushkov, D.E.

    2002-01-01

    Nitrous oxide (N2O) atmospheric emission from different agricultural soil types in Russia was evaluated based on published data on single input of nitrogen (N) fertilizers. For most of experiments the rates of fertilization varied from 40 to 75 and from 160 to 264 kg/ha in active matter and they were considered separately. The higher rates of synthetic fertilizers (160 to 264 kg/ha) reduced relative gaseous loss of N as N2O (N2O-N). Evidently, if nitrate (NO3) concentrations were high, the low content of organic carbon (C) and oxygen (O) restricted soil microbiological activity and consequently formation of N2O. The majority of gaseous loss of N2O-N occurred within 140 days after the input of fertilizers. The N2O emission factors derived for chernozem and soddy podzolic soil are 0.0126 and 0.0238 kg N2O-N/kg N respectively. In 1990, the use of N fertilizers in national agriculture caused the release of 53 Gg N2O-N that constituted 6% of global N2O emission. Later on, the emission dropped because of decreased use of N fertilizers, and in 1998 it was almost 21% of the 1990 level

  18. Representative concentration pathways and mitigation scenarios for nitrous oxide

    International Nuclear Information System (INIS)

    Davidson, Eric A

    2012-01-01

    The challenges of mitigating nitrous oxide (N 2 O) emissions are substantially different from those for carbon dioxide (CO 2 ) and methane (CH 4 ), because nitrogen (N) is essential for food production, and over 80% of anthropogenic N 2 O emissions are from the agricultural sector. Here I use a model of emission factors of N 2 O to demonstrate the magnitude of improvements in agriculture and industrial sectors and changes in dietary habits that would be necessary to match the four representative concentration pathways (RCPs) now being considered in the fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC). Stabilizing atmospheric N 2 O by 2050, consistent with the most aggressive of the RCP mitigation scenarios, would require about 50% reductions in emission factors in all sectors and about a 50% reduction in mean per capita meat consumption in the developed world. Technologies exist to achieve such improved efficiencies, but overcoming social, economic, and political impediments for their adoption and for changes in dietary habits will present large challenges. (letter)

  19. UK emissions of the greenhouse gas nitrous oxide

    Science.gov (United States)

    Skiba, U.; Jones, S. K.; Dragosits, U.; Drewer, J.; Fowler, D.; Rees, R. M.; Pappa, V. A.; Cardenas, L.; Chadwick, D.; Yamulki, S.; Manning, A. J.

    2012-01-01

    Signatories of the Kyoto Protocol are obliged to submit annual accounts of their anthropogenic greenhouse gas emissions, which include nitrous oxide (N2O). Emissions from the sectors industry (3.8 Gg), energy (14.4 Gg), agriculture (86.8 Gg), wastewater (4.4 Gg), land use, land-use change and forestry (2.1 Gg) can be calculated by multiplying activity data (i.e. amount of fertilizer applied, animal numbers) with simple emission factors (Tier 1 approach), which are generally applied across wide geographical regions. The agricultural sector is the largest anthropogenic source of N2O in many countries and responsible for 75 per cent of UK N2O emissions. Microbial N2O production in nitrogen-fertilized soils (27.6 Gg), nitrogen-enriched waters (24.2 Gg) and manure storage systems (6.4 Gg) dominate agricultural emission budgets. For the agricultural sector, the Tier 1 emission factor approach is too simplistic to reflect local variations in climate, ecosystems and management, and is unable to take into account some of the mitigation strategies applied. This paper reviews deviations of observed emissions from those calculated using the simple emission factor approach for all anthropogenic sectors, briefly discusses the need to adopt specific emission factors that reflect regional variability in climate, soil type and management, and explains how bottom-up emission inventories can be verified by top-down modelling. PMID:22451103

  20. A critical analysis of nitrous oxide emissions from animal manure

    International Nuclear Information System (INIS)

    Klemendtsson, Aa.K.; Klemedtsson, L.

    2002-01-01

    Emission of nitrous oxide, N 2 0, alter manure applications to agricultural soil is composed of two components. The first is the immediately increased potential for N 2 0 production due to favourable conditions in the manure-soil environment. More N 2 0 is produced and emitted when the nitrogen content of the manure is high, especially the mineral nitrogen content. The amount of carbon available for microbiological decomposition and water content regulate the oxygen availability, which is important for N 2 0 production in both nitrification and denitrification. The balance between mineralisation of organically bound nitrogen and immobilisation of mineral nitrogen by microorganisms and plants control the availability of N for N 2 0 production. The initial burst of N 2 0 to the atmosphere following manure application may last for two months, while a second component is long term and due to nitrogen in organic matter accumulating in the soil, resulting in a small increase in background emissions over many years due to nitrogen cycling. The IPCC emission factor for N 2 0 emission due to manure addition accounts for the increased emission of N 2 0 during the first year, whereas the long-term emission is not included. (au)

  1. Nitrous oxide production associated with coastal marine invertebrates

    DEFF Research Database (Denmark)

    Heisterkamp, Ines Maria; Schramm, Andreas; de Beer, Dirk

    2010-01-01

    Several freshwater and terrestrial invertebrate species emit the greenhouse gas nitrous oxide (N2O). The N2O production associated with these animals was ascribed to incomplete denitrification by ingested sediment or soil bacteria. The present study shows that many marine invertebrates also emit N2......O at substantial rates. A total of 19 invertebrate species collected in the German Wadden Sea and in Aarhus Bay, Denmark, and 1 aquacultured shrimp species were tested for N2O emission. Potential N2O emission rates ranged from 0 to 1.354 nmol ind.–1 h–1, with an average rate of 0.320 nmol ind.–1 h–1...... with an experimentally cleaned shell. Thus, the N2O production associated with marine invertebrates is apparently not due to gut denitrification in every species, but may also result from microbial activity on the external surfaces of animals. The high abundance and potential N2O emission rates of many marine...

  2. Nitrous oxide emission reduction in temperate biochar-amended soils

    Science.gov (United States)

    Felber, R.; Hüppi, R.; Leifeld, J.; Neftel, A.

    2012-01-01

    Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG) emissions. In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O) and carbon dioxide (CO2). In contrast, evidence is scarce for temperate soils. In a three-factorial laboratory incubation experiment two different temperate agricultural soils were amended with green waste and coffee grounds biochar. N2O and CO2 emissions were measured at the beginning and end of a three month incubation. The experiments were conducted under three different conditions (no additional nutrients, glucose addition, and nitrate and glucose addition) representing different field conditions. We found mean N2O emission reductions of 60 % compared to soils without addition of biochar. The reduction depended on biochar type and soil type as well as on the age of the samples. CO2 emissions were slightly reduced, too. NO3- but not NH4+ concentrations were significantly reduced shortly after biochar incorporation. Despite the highly significant suppression of N2O emissions biochar effects should not be transferred one-to-one to field conditions but need to be tested accordingly.

  3. Strategies for enhanced deammonification performance and reduced nitrous oxide emissions.

    Science.gov (United States)

    Leix, Carmen; Drewes, Jörg E; Ye, Liu; Koch, Konrad

    2017-07-01

    Deammonification's performance and associated nitrous oxide emissions (N 2 O) depend on operational conditions. While studies have investigated factors for high performances and low emissions separately, this study investigated optimizing deammonification performance while simultaneously reducing N 2 O emissions. Using a design of experiment (DoE) method, two models were developed for the prediction of the nitrogen removal rate and N 2 O emissions during single-stage deammonification considering three operational factors (i.e., pH value, feeding and aeration strategy). The emission factor varied between 0.7±0.5% and 4.1±1.2% at different DoE-conditions. The nitrogen removal rate was predicted to be maximized at settings of pH 7.46, intermittent feeding and aeration. Conversely, emissions were predicted to be minimized at the design edges at pH 7.80, single feeding, and continuous aeration. Results suggested a weak positive correlation between the nitrogen removal rate and N 2 O emissions, thus, a single optimizing operational set-point for maximized performance and minimized emissions did not exist. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Nitrous oxide flux from landfill leachate-sawdust nitrogenous compost

    International Nuclear Information System (INIS)

    Hui, C.H.; So, M.K.; Lee, C.M.; Chan, G.Y.S.

    2003-01-01

    Composted nitrogenous waste has the potential to produce excessive amounts of nitrous oxide (N 2 O), a potent greenhouse gas that also contributes to stratospheric ozone depletion. In this laboratory study, sawdust was irrigated with varying amounts of landfill leachate with high NH 4 + -N content (3950 mg l -1 ). Physicochemical properties, including the amount of N 2 O produced, were monitored during the composting process over 28 days. A rapid decline in NH 4 + -N in the first 4 days and increasing NO 3 - -N for 11 days was followed by lower but stabilized levels of available-N, even with repeated leachate irrigation. Less than 0.03% of the leachate-applied N was lost as N 2 O. Higher leachate applications as much as tripled N 2 O production, but this represented a lesser proportion overall of the total nitrogen. Addition of glucose to the composting process had no significant effect on N 2 O production. The derived sawdust-leachate compost supported healthy growth of Sesbania rostrata. It is concluded that compost can be produced from sawdust irrigated with landfill leachate without substantial emission of N 2 O, although excessive flux of N 2 O remains about high application rates over longer time periods. (Author)

  5. Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms.

    Science.gov (United States)

    Torres, M J; Simon, J; Rowley, G; Bedmar, E J; Richardson, D J; Gates, A J; Delgado, M J

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nitric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the application of synthetic nitrogen-containing fertilizers. Thus, mitigation strategies must be developed which increase (or at least do not negatively impact) on agricultural efficiency whilst decrease the levels of N2O released. This aim is particularly important in the context of the ever expanding population and subsequent increased burden on the food chain. More than two-thirds of N2O emissions from soils can be attributed to bacterial and fungal denitrification and nitrification processes. In ammonia-oxidizing bacteria, N2O is formed through the oxidation of hydroxylamine to nitrite. In denitrifiers, nitrate is reduced to N2 via nitrite, NO and N2O production. In addition to denitrification, respiratory nitrate ammonification (also termed dissimilatory nitrate reduction to ammonium) is another important nitrate-reducing mechanism in soil, responsible for the loss of nitrate and production of N2O from reduction of NO that is formed as a by-product of the reduction process. This review will synthesize our current understanding of the environmental, regulatory and biochemical control of N2O emissions by nitrate-reducing bacteria and point to new solutions for agricultural GHG mitigation. © 2016 Elsevier Ltd. All rights reserved.

  6. Model-based evaluation of the role of Anammox on nitric oxide and nitrous oxide productions in membrane aerated biofilm reactor

    DEFF Research Database (Denmark)

    Ni, Bing-Jie; Smets, Barth F.; Yuan, Zhiguo

    2013-01-01

    A multispecies one-dimensional biofilm model considering nitric oxide (NO) and nitrous oxide (N2O) productions for membrane aerated biofilm reactor (MABR) that remove nitrogen autotrophically through aerobic ammonia oxidation followed by Anammox is used to study the role of Anammox activity...... on the total nitrogen (TN) removal and the productions of NO and N2O. The model is applied to evaluate how periodic aeration as a control parameter reduces NO and N2O production but maintains high TN removal in MABR. The simulation results show over 3.5% of the removed TN could be attributed to NO and N2O...... production in MABR under the operational conditions optimal for TN removal (72%). An analysis of factors governing the Anammox activity in MABR shows that enhancing Anammox activity not only helps to achieve a high level of nitrogen removal but also reduces NO and N2O productions. Comparison of aeration...

  7. Suffocation caused by plastic wrap covering the face combined with nitrous oxide inhalation.

    Science.gov (United States)

    Leth, Peter Mygind; Astrup, Birgitte Schmidt

    2017-09-01

    Suicide using a combination of a plastic bag over the head and inhalation of a non-irritating gas, such as helium, argon or nitrogen, has been reported in the literature. Here an unusual suicide method in a 17-year old man by suffocation from covering the face with household plastic wrap, combined with nitrous oxide inhalation, is presented. The case was reviewed based on police, autopsy and hospital reports. A PubMed search for scientific literature related to nitrous oxide abuse and suicide by suffocation was performed and our findings discussed in relation to the scientific literature found. The deceased was a 17-year old man who was found with the nose and mouth closed with a piece of kitchen plastic wrap. The plastic wrap had been removed prior to autopsy. Autopsy findings were suggestive of asphyxia, but were otherwise negative. Nitrous oxide was detected in the brain and lung tissue with headspace-gas chromatography-mass spectrometry (headspace-GCMS). The cause of death was assumed to be suffocation caused by plastic wrap covering the face, combined with nitrous oxide inhalation. Suicide was suspected because of a history of depression for several months. Nitrous oxide, also known as laughing gas, has a euphoric effect and is used as a recreational inhalant drug that can be purchased legally. Deaths caused by recreational nitrous oxide abuse are rare but may occur if used in combination with a plastic bag over the head. This is the first report of suicide by suffocation by external obstruction combined with nitrous oxide inhalation.

  8. Effects of temperature on nitrous oxide (N2O) emission from intensive aquaculture system.

    Science.gov (United States)

    Paudel, Shukra Raj; Choi, Ohkyung; Khanal, Samir Kumar; Chandran, Kartik; Kim, Sungpyo; Lee, Jae Woo

    2015-06-15

    This study examines the effects of temperature on nitrous oxide (N2O) emissions in a bench-scale intensive aquaculture system rearing Koi fish. The water temperature varied from 15 to 24 °C at interval of 3 °C. Both volumetric and specific rate for nitrification and denitrification declined as the temperature decreased. The concentrations of ammonia and nitrite, however, were lower than the inhibitory level for Koi fish regardless of temperature. The effects of temperature on N2O emissions were significant, with the emission rate and emission factor increasing from 1.11 to 1.82 mg N2O-N/d and 0.49 to 0.94 mg N2O-N/kg fish as the temperature decreased from 24 to 15 °C. A global map of N2O emission from aquaculture was established by using the N2O emission factor depending on temperature. This study demonstrates that N2O emission from aquaculture is strongly dependent on regional water temperatures as well as on fish production. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. An assessment of nitrification inhibitors to reduce nitrous oxide emissions from UK agriculture

    International Nuclear Information System (INIS)

    Misselbrook, T H; Cardenas, L M; Camp, V; Thorman, R E; Williams, J R; Rollett, A J; Chambers, B J

    2014-01-01

    A trial was conducted consisting of 14 experiments across sites in England of contrasting soil type and annual rainfall to assess the effectiveness of nitrification inhibitors (predominantly dicyandiamide (DCD) but limited assessment also of 3, 4-dimethylpyrazole phosphate (DMPP) and a commercial product containing two pyrazole derivatives) in reducing direct nitrous oxide (N 2 O) emissions from fertilizer nitrogen (N), cattle urine and cattle slurry applications to land. Measurements were also made of the impact on ammonia (NH 3 ) volatilization, nitrate (NO 3 − ) leaching, crop yield and crop N offtake. DCD proved to be very effective in reducing direct N 2 O emissions following fertilizer and cattle urine applications, with mean reduction efficiencies of 39, 69 and 70% for ammonium nitrate, urea and cattle urine, respectively. When included with cattle slurry a mean, non-significant reduction of 56% was observed. There were no N 2 O emission reductions observed from the limited assessments of the other nitrification inhibitors. Generally, there were no impacts of the nitrification inhibitors on NH 3 volatilization, NO 3 − leaching, crop yield or crop N offtake. Use of DCD could give up to 20% reduction in N 2 O emissions from UK agriculture, but cost-effective delivery mechanisms are required to encourage adoption by the sector. Direct N 2 O emissions from the studied sources were substantially lower than IPCC default values and development of UK country-specific emission factors for use in inventory compilation is warranted. (paper)

  10. Influence of Nitrous Oxide Anesthesia, B-Vitamins, and MTHFR gene polymorphisms on Perioperative Cardiac Events: The Vitamins in Nitrous Oxide (VINO) Randomized Trial

    Science.gov (United States)

    Nagele, Peter; Brown, Frank; Francis, Amber; Scott, Mitchell G.; Gage, Brian F.; Miller, J. Philip

    2013-01-01

    Background Nitrous oxide causes an acute increase in plasma homocysteine that is more pronounced in patients with the MTHFR C677T or A1298C gene variant. In this randomized controlled trial we sought to determine if patients carrying the MTHFR C677T or A1298C variant had a higher risk for perioperative cardiac events after nitrous oxide anesthesia and if this risk could be mitigated by B-vitamins. Methods We randomized adult patients with cardiac risk factors undergoing noncardiac surgery to receive nitrous oxide plus intravenous B-vitamins before and after surgery or to nitrous oxide and placebo. Serial cardiac biomarkers and 12-lead electrocardiograms were obtained. The primary study endpoint was the incidence of myocardial injury, as defined by cardiac troponin I elevation within the first 72 hours after surgery. Results A total of 500 patients completed the trial. Patients who were homozygous for either MTHFR C677T or A1298C gene variant (n= 98; 19.6%) had no increased rate of postoperative cardiac troponin I elevation compared to wild-type and heterozygous patients (11.2% vs. 14.0%; relative risk 0.96, 95% CI 0.85 to 1.07, p=0.48). B-vitamins blunted the rise in homocysteine, but had no effect on cardiac troponin I elevation compared to patients receiving placebo (13.2% vs. 13.6%; relative risk 1.02, 95% CI 0.78 to 1.32, p=0.91). Conclusions Neither MTHFR C677T and A1298C gene variant nor acute homocysteine increase are associated with perioperative cardiac troponin elevation after nitrousoxide anesthesia. B-vitamins blunt nitrous oxide-induced homocysteine increase but have no effect on cardiac troponin elevation. PMID:23856660

  11. Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

    Science.gov (United States)

    Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

    2012-12-01

    Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (<50 μM) compared to growth at 1 mM. Although the ammonia oxidation pathway has not been fully elucidated, we have shown that nitric oxide (NO) appears to be a key intermediate: exponentially growing HL72 produces significant NO and the removal of NO using a scavenger reversibly inhibits growth. In addition to AMO, the HL72 genome also contains sequences for a urease encoded by subunits ureABC and an active urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially

  12. The ideal oxygen/nitrous oxide fresh gas flow sequence with the Anesthesia Delivery Unit machine.

    Science.gov (United States)

    Hendrickx, Jan F A; Cardinael, Sara; Carette, Rik; Lemmens, Hendrikus J M; De Wolf, Andre M

    2007-06-01

    To determine whether early reduction of oxygen and nitrous oxide fresh gas flow from 6 L/min to 0.7 L/min could be accomplished while maintaining end-expired nitrous oxide concentration > or =50% with an Anesthesia Delivery Unit anesthesia machine. Prospective, randomized clinical study. Large teaching hospital in Belgium. 53 ASA physical status I and II patients requiring general endotracheal anesthesia and controlled mechanical ventilation. Patients were randomly assigned to one of 4 groups depending on the duration of high oxygen/nitrous oxide fresh gas flow (two and 4 L/min, respectively) before lowering total fresh gas flow to 0.7 L/min (0.3 and 0.4 L/min oxygen and nitrous oxide, respectively): one, two, three, or 5 minutes (1-minute group, 2-minute group, 3-minute group, and 5-minute group), with n = 10, 12, 13, and 8, respectively. The course of the end-expired nitrous oxide concentration and bellows volume deficit at end-expiration was compared among the 4 groups during the first 30 minutes. At the end of the high-flow period the end-expired nitrous oxide concentration was 35.6 +/- 6.2%, 48.4 +/- 4.8%, 53.7 +/- 8.7%, and 57.3 +/- 1.6% in the 4 groups, respectively. Thereafter, the end-expired nitrous oxide concentration decreased to a nadir of 36.1 +/- 4.5%, 45.4 +/- 3.8%, 50.9 +/- 6.1%, and 55.4 +/- 2.8% after three, 4, 6, and 8 minutes after flows were lowered in the 1- to 5-minute groups, respectively. A decrease in bellows volume was observed in most patients, but was most pronounced in the 2-minute group. The bellows volume deficit gradually faded within 15 to 20 minutes in all 4 groups. A 3-minute high-flow period (oxygen and nitrous oxide fresh gas flow of 2 and 4 L/min, respectively) suffices to attain and maintain end-expired nitrous oxide concentration > or =50% and ensures an adequate bellows volume during the ensuing low-flow period.

  13. Enhanced biogenic emissions of nitric oxide and nitrous oxide following surface biomass burning

    Science.gov (United States)

    Anderson, Iris C.; Levine, Joel S.; Poth, Mark A.; Riggan, Philip J.

    1988-01-01

    Recent measurements indicate significantly enhanced biogenic soil emissions of both nitric oxide (NO) and nitrous oxide (N2O) following surface burning. These enhanced fluxes persisted for at least six months following the burn. Simultaneous measurements indicate enhanced levels of exchangeable ammonium in the soil following the burn. Biomass burning is known to be an instantaneous source of NO and N2O resulting from high-temperature combustion. Now it is found that biomass burning also results in significantly enhanced biogenic emissions of these gases, which persist for months following the burn.

  14. Electrochemical reduction of nitrous oxide on La1-xSrxFeO3 perovskites

    DEFF Research Database (Denmark)

    Kammer Hansen, Kent

    2010-01-01

    The electrochemical reduction of nitrous oxide and oxygen has been studied on cone-shaped electrodes of La1-xSrxFeO3-delta perovskites in an all solid state cell, using cyclic voltammetry. It was shown that the activity of the La1-xSrxFeO3-delta perovskites for the electrochemical reduction...... of nitrous oxide mainly depends on the amount of Fe(III) and oxide ion vacancies. The activity of the La1-xSrxFeO3-delta perovskites towards the electrochemical reduction of nitrous oxide is much lower than the activity of the La1-xSrxFeO3-delta perovskites towards the electrochemical reduction of oxygen...

  15. Hybrid Nitrous Oxide Production from a Partial Nitrifying Bioreactor: Hydroxylamine Interactions with Nitrite.

    Science.gov (United States)

    Terada, Akihiko; Sugawara, Sho; Hojo, Keisuke; Takeuchi, Yuki; Riya, Shohei; Harper, Willie F; Yamamoto, Tomoko; Kuroiwa, Megumi; Isobe, Kazuo; Katsuyama, Chie; Suwa, Yuichi; Koba, Keisuke; Hosomi, Masaaki

    2017-03-07

    The goal of this study was to elucidate the mechanisms of nitrous oxide (N 2 O) production from a bioreactor for partial nitrification (PN). Ammonia-oxidizing bacteria (AOB) enriched from a sequencing batch reactor (SBR) were subjected to N 2 O production pathway tests. The N 2 O pathway test was initiated by supplying an inorganic medium to ensure an initial NH 4 + -N concentration of 160 mg-N/L, followed by 15 NO 2 - (20 mg-N/L) and dual 15 NH 2 OH (each 17 mg-N/L) spikings to quantify isotopologs of gaseous N 2 O ( 44 N 2 O, 45 N 2 O, and 46 N 2 O). N 2 O production was boosted by 15 NH 2 OH spiking, causing exponential increases in mRNA transcription levels of AOB functional genes encoding hydroxylamine oxidoreductase (haoA), nitrite reductase (nirK), and nitric oxide reductase (norB) genes. Predominant production of 45 N 2 O among N 2 O isotopologs (46% of total produced N 2 O) indicated that coupling of 15 NH 2 OH with 14 NO 2 - produced N 2 O via N-nitrosation hybrid reaction as a predominant pathway. Abiotic hybrid N 2 O production was also observed in the absence of the AOB-enriched biomass, indicating multiple pathways for N 2 O production in a PN bioreactor. The additional N 2 O pathway test, where 15 NH 4 + was spiked into 400 mg-N/L of NO 2 - concentration, confirmed that the hybrid N 2 O production was a dominant pathway, accounting for approximately 51% of the total N 2 O production.

  16. Changes in heart rate variability during anaesthesia induction using sevoflurane or isoflurane with nitrous oxide.

    Science.gov (United States)

    Nishiyama, Tomoki

    2016-01-01

    The purpose of this study was to compare cardiac sympathetic and parasympathetic balance using heart rate variability (HRV) during induction of anaesthesia between sevoflurane and isoflurane in combination with nitrous oxide. 40 individuals aged from 30 to 60 years, scheduled for general anaesthesia were equally divided into sevoflurane or isoflurane groups. After 100% oxygen inhalation for a few minutes, anaesthesia was induced with nitrous oxide 3 L min-1, oxygen 3 L min-1 and sevoflurane or isoflurane. Sevoflurane or isoflurane concentration was increased by 0.5% every 2 to 3 breaths until 5% was attained for sevoflurane, or 3% for isoflurane. Vecuronium was administered to facilitate tracheal intubation. After intubation, sevoflurane was set to 2% while isoflurane was set to 1% with nitrous oxide with oxygen (1:1) for 5 min. Both sevoflurane and isoflurane provoked a decrease in blood pressure, total power, the low frequency component (LF), and high frequency component (HF) of HRV. Although the heart rate increased during isoflurane anaesthesia, it decreased under sevoflurane. The power of LF and HF also decreased in both groups. LF was higher in the isoflurane group while HF was higher in the sevoflurane group. The LF/HF ratio increased transiently in the isoflurane group, but decreased in the sevoflurane group. Anaesthesia induction with isoflurane-nitrous oxide transiently increased cardiac sympathetic activity, while sevoflurane-nitrous oxide decreased both cardiac sympathetic and parasympathetic activities. The balance of cardiac parasympathetic/sympathetic activity was higher in sevoflurane anaesthesia.

  17. Increased norepinephrine release from dog pulmonary artery caused by nitrous oxide

    International Nuclear Information System (INIS)

    Rorie, D.K.; Tyce, G.M.; Sill, J.C.

    1986-01-01

    The effects of nitrous oxide on the release and metabolism of norepinephrine (NE) at neuroeffector junctions in dog pulmonary artery were examined. Helical strips of artery were incubated in Krebs-Ringer solution containing L-( 3 H)NE and mounted for superfusion. The arterial strips were studied in the presence of 95% oxygen-5% carbon dioxide, 70% nitrogen-30% oxygen, or 70% nitrous oxide-30% oxygen. During the 60 min of each experiment, five samples of superfusion fluid were collected for analysis and the effluxes of ( 3 H)NE and its radiolabeled metabolites were measured before and during electrical stimulation and during recovery from stimulation. ( 3 H)Norepinephrine was separated from its metabolites in the superfusate and in extracts of artery by column chromatography and quantitated by liquid scintillation spectrometry. Nitrous oxide significantly increased the fractional loss of total radioactivity and the amount of NE in the superfusate both during resting conditions and during stimulation. Nitrous oxide had no effect on the proportions of radioactivity among metabolites of NE in the superfusate or on the profile of NE metabolites remaining in the tissue after experimentation. These findings are consistent with increased NE release as a direct effect of nitrous oxide on nerve endings

  18. Large-scale Modeling of Nitrous Oxide Production: Issues of Representing Spatial Heterogeneity

    Science.gov (United States)

    Morris, C. K.; Knighton, J.

    2017-12-01

    Nitrous oxide is produced from the biological processes of nitrification and denitrification in terrestrial environments and contributes to the greenhouse effect that warms Earth's climate. Large scale modeling can be used to determine how global rate of nitrous oxide production and consumption will shift under future climates. However, accurate modeling of nitrification and denitrification is made difficult by highly parameterized, nonlinear equations. Here we show that the representation of spatial heterogeneity in inputs, specifically soil moisture, causes inaccuracies in estimating the average nitrous oxide production in soils. We demonstrate that when soil moisture is averaged from a spatially heterogeneous surface, net nitrous oxide production is under predicted. We apply this general result in a test of a widely-used global land surface model, the Community Land Model v4.5. The challenges presented by nonlinear controls on nitrous oxide are highlighted here to provide a wider context to the problem of extraordinary denitrification losses in CLM. We hope that these findings will inform future researchers on the possibilities for model improvement of the global nitrogen cycle.

  19. Sedation with nitrous oxide compared with no sedation during catheterization for urologic imaging in children

    International Nuclear Information System (INIS)

    Zier, Judith L.; Kvam, Kathryn A.; Kurachek, Stephen C.; Finkelstein, Marsha

    2007-01-01

    Various strategies to mitigate children's distress during voiding cystourethrography (VCUG) have been described. Sedation with nitrous oxide is comparable to that with oral midazolam for VCUG, but a side-by-side comparison of nitrous oxide sedation and routine care is lacking. The effects of sedation/analgesia using 70% nitrous oxide and routine care for VCUG and radionuclide cystography (RNC) were compared. A sample of 204 children 4-18 years of age scheduled for VCUG or RNC with sedation or routine care were enrolled in this prospective study. Nitrous oxide/oxygen (70%/30%) was administered during urethral catheterization to children in the sedated group. The outcomes recorded included observed distress using the Brief Behavioral Distress Score, self-reported pain, and time in department. The study included 204 patients (99 nonsedated, 105 sedated) with a median age of 6.3 years (range 4.0-15.2 years). Distress and pain scores were greater in nonsedated than in sedated patients (P < 0.001). Time in department was longer in the sedated group (90 min vs. 30 min); however, time from entry to catheterization in a non-imaging area accounted for most of the difference. There was no difference in radiologic imaging time. Sedation with nitrous oxide is effective in reducing distress and pain during catheterization for VCUG or RNC in children. (orig.)

  20. Nitrous Oxides Ozone Destructiveness Under Different Climate Scenarios

    Science.gov (United States)

    Kanter, David R.; McDermid, Sonali P.

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas and ozone depleting substance as well as a key component of the nitrogen cascade. While emissions scenarios indicating the range of N2O's potential future contributions to radiative forcing are widely available, the impact of these emissions scenarios on future stratospheric ozone depletion is less clear. This is because N2O's ozone destructiveness is partially dependent on tropospheric warming, which affects ozone depletion rates in the stratosphere. Consequently, in order to understand the possible range of stratospheric ozone depletion that N2O could cause over the 21st century, it is important to decouple the greenhouse gas emissions scenarios and compare different emissions trajectories for individual substances (e.g. business-as-usual carbon dioxide (CO2) emissions versus low emissions of N2O). This study is the first to follow such an approach, running a series of experiments using the NASA Goddard Institute for Space Sciences ModelE2 atmospheric sub-model. We anticipate our results to show that stratospheric ozone depletion will be highest in a scenario where CO2 emissions reductions are prioritized over N2O reductions, as this would constrain ozone recovery while doing little to limit stratospheric NOx levels (the breakdown product of N2O that destroys stratospheric ozone). This could not only delay the recovery of the stratospheric ozone layer, but might also prevent a return to pre-1980 global average ozone concentrations, a key goal of the international ozone regime. Accordingly, we think this will highlight the importance of reducing emissions of all major greenhouse gas emissions, including N2O, and not just a singular policy focus on CO2.

  1. Modelling nitrous oxide emissions from grazed grassland systems

    International Nuclear Information System (INIS)

    Wang Junye; Cardenas, Laura M.; Misselbrook, Tom H.; Cuttle, Steve; Thorman, Rachel E.; Li Changsheng

    2012-01-01

    Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N 2 O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N 2 O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N 2 O emissions increased as the grazing intensity increased. - Highlights: ► Parameterisation of grazing system using grazing intensity. ► Modification of UK D NDC for the UK soil and weather conditions. ► Validation of the UK D NDC against measured data of N 2 O emissions in three UK sites. ► Estimating influence of animal grazing practises on N 2 O emissions. - Grazing system was parameterised using grazing intensity and UK-DNDC model was modified and validated against measured data of N 2 O emissions in three UK sites.

  2. Modelling nitrous oxide emissions from cropland at the regional scale

    Directory of Open Access Journals (Sweden)

    Gabrielle Benoît

    2006-11-01

    Full Text Available Arable soils are a large source of nitrous oxide (N2O emissions, making up half of the biogenic emissions worldwide. Estimating their source strength requires methods capable of capturing the spatial and temporal variability of N2O emissions, along with the effects of crop management. Here, we applied a process-based model, CERES, with geo-referenced input data on soils, weather, and land use to map N2O emissions from wheat-cropped soils in three agriculturally intensive regions in France. Emissions were mostly controlled by soil type and local climate conditions, and only to a minor extent by the doses of fertilizer nitrogen applied. As a result, the direct emission factors calculated at the regional level were much smaller (ranging from 0.0007 to 0.0033 kg N2O-N kg–1 N than the value of 0.0125 kg N2O-N kg–1 N currently recommended in the IPCC Tier 1 methodology. Regional emissions were far more sensitive to the soil microbiological parameter s governing denitrification and its fraction evolved as N2O, soil bulk density, and soil initial inorganic N content. Mitigation measures should therefore target a reduction in the amount of soil inorganic N upon sowing of winter crops, and a decrease of the soil N2O production potential itself. From a general perspective, taking into account the spatial variability of soils and climate thereby appears necessary to improve the accuracy of national inventories, and to tailor mitigation strategies to regional characteristics. The methodology and results presented here may easily be transferred to winter oilseed rape, whose has growing cycle and fertilser requirements are similar.

  3. Nitrous oxide emission from denitrification in stream and river networks

    Science.gov (United States)

    Beaulieu, J.J.; Tank, J.L.; Hamilton, S.K.; Wollheim, W.M.; Hall, R.O.; Mulholland, P.J.; Peterson, B.J.; Ashkenas, L.R.; Cooper, L.W.; Dahm, Clifford N.; Dodds, W.K.; Grimm, N. B.; Johnson, S.L.; McDowell, W.H.; Poole, G.C.; Maurice, Valett H.; Arango, C.P.; Bernot, M.J.; Burgin, A.J.; Crenshaw, C.L.; Helton, A.M.; Johnson, L.T.; O'Brien, J. M.; Potter, J.D.; Sheibley, R.W.; Sobota, D.J.; Thomas, S.M.

    2011-01-01

    Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N 2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The fraction of denitrified N that escapes as N2O rather than N2 (i.e., the N2O yield) is an important determinant of how much N2O is produced by river networks, but little is known about the N2O yield in flowing waters. Here, we present the results of whole-stream 15N-tracer additions conducted in 72 headwater streams draining multiple land-use types across the United States. We found that stream denitrification produces N2O at rates that increase with stream water nitrate (NO3-) concentrations, but that production, but does not increase the N2O yield. In our study, most streams were sources of N2O to the atmosphere and the highest emission rates were observed in streams draining urban basins. Using a global river network model, we estimate that microbial N transformations (e.g., denitrification and nitrification) convert at least 0.68 Tg??y -1 of anthropogenic N inputs to N2O in river networks, equivalent to 10% of the global anthropogenic N2O emission rate. This estimate of stream and river N2O emissions is three times greater than estimated by the Intergovernmental Panel on Climate Change.

  4. Measurements of nitrous oxide emissions from vegetable production in China

    Science.gov (United States)

    Xiong, Zhengqin; Xie, Yingxin; Xing, Guangxi; Zhu, Zhaoliang; Butenhoff, Chris

    Nitrous oxide (N 2O) emissions resulting from Chinese vegetable production were measured. A site in suburban Nanjing (East coast; Jiangsu Province) was monitored from November 2001 to January 2003, in which five consecutive vegetable crops were sown. The crops consisted of radish, baby bok choy, lettuce, second planting of baby bok choy, and finally celery. Results suggested that N 2O emission events occur in pulses. The average N 2O-N flux for all five crops was 148±9 μg N m -2 h -1 and the average emission rate was 12±0.7 kg N ha -1. The average seasonal emission fluxes ranged from 37 μg N m -2 h -1 in the radish plot to 300 μg N m -2 h -1 in the celery plot. The celery field produced the greatest cumulative emission of 5.8 kg N ha -1 while the baby bok choy field had the lowest rate of 0.96-1.0 kg N ha -1. In total, 0.73% of applied fertilizer N was emitted as N 2O-N as a whole. The lettuce field had the largest emission factor of 2.2%. Results indicate that emissions from vegetable field are a potential source of national N 2O inventory. Temporal variation is much greater than spatial variation and the corresponding CV averaged 115% and 22%, respectively. Under the same total sampling quantity, increasing sampling frequency is more important than increasing spatial replicates.

  5. The dependence of the discharge of nitrous oxide by ordinary chernozem steppe of the Central-Chernozem Region of Russia from the content of humus, nitrogen and enzymatic activity

    Science.gov (United States)

    Avksentev, Alexey; Negrobova, Elena; Kramareva, Tatiana; Moiseeva, Evgenya

    2016-04-01

    The dependence of the discharge of nitrous oxide by ordinary chernozem steppe of the Central-Chernozem Region of Russia from the content of humus, nitrogen and enzymatic activity Alexey Avksentev, Elena Negrobova, Tatiana Kramareva, Evgenya Moiseeva 394000 Voronezh, Universitetskaya square, 1 Voronezh State University Nitrous oxide is emitted by soil as a result of microbiological processes, ranks third in the list of aggressive greenhouse gas after carbon dioxide and methane. Nitrous oxide is formed during nitrification and denitrification of ammonia that enters the soil during microbial decomposition of complex organic compounds. Denitrification can be direct and indirect. In the microbiological process of recovery of nitrates involved of the organic substance. In aerobic conditions microorganisms denitrificator behave like normal saprotrophs and oxidize organic matter in the act of breathing oxygen. Thus, they operate at different times two enzyme systems: the electron transport chain with an oxygen acceptor in aerobic and restoration of nitrates under anaerobic conditions. Investigation of the emission of nitrous oxide by ordinary Chernozem steppe of the Central-Chernozem Region showed that it depends on the type of cenosis and the content of available forms of nitrogen. Natural ecosystems emit nitrous oxide more than the soil of arable land. The dependence of the emission of nitrous oxide from the humus content shows positive trend, but the aggregation of data, significant differences are not detected. Research shows that nitrous oxide emissions are seasonal. So the autumn season is characterized by nitrous oxide emissions than spring. Enzymatic processes are an important link in the biological cycle of elements and, consequently, participate in the process of decomposition of organic matter, nitrification and other processes. Analysis of the data on enzyme activity of ordinary Chernozem and the intensity of emission of N20 shows a clear relationship between

  6. Catalytic Reduction of Nitrous Oxide with Carbon Monoxide over Calcined Co–Mn–Al Hydrotalcite

    Czech Academy of Sciences Publication Activity Database

    Pacultová, K.; Obalová, L.; Kovanda, F.; Jirátová, Květa

    2008-01-01

    Roč. 137, 2-4 (2008), s. 358-389 ISSN 0920-5861 R&D Projects: GA ČR(CZ) GA106/05/0366 Institutional research plan: CEZ:AV0Z40720504 Keywords : nitrous oxide * carbon monoxide * mixed oxide catalysts Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 3.004, year: 2008

  7. Control of occupational exposure to nitrous oxide in the dental operatory

    Energy Technology Data Exchange (ETDEWEB)

    Whitcher, C.E.; Zimmerman, D.C.; Tonn, E.M.; Piziali, R.L.

    1977-10-01

    Methods were developed for controlling the dental team's occupational exposure to nitrous oxide. The most applicable and effective use of these methods included the use of properly maintained gas delivery equipment, a double-walled scavenging nosepiece and vented suction machine, and minimizing speech by the patient. These methods were evaluated by measuring concentrations of nitrous oxide present in the air inspired by dental personnel. Before their use, the dentist inhaled 900 ppM nitrous oxide; their application reduced his inhaled concentration to 31 ppM, representing a 97% reduction. These methods were well accepted during 157 procedures completed by a group of eight dentists engaged in private practice (four general practitioners, two pedodontists, and two oral surgeons).

  8. Suffocation caused by plastic wrap covering the face combined with nitrous oxide inhalation

    DEFF Research Database (Denmark)

    Leth, Peter Mygind; Astrup, Birgitte Schmidt

    2017-01-01

    Suicide using a combination of a plastic bag over the head and inhalation of a non-irritating gas, such as helium, argon or nitrogen, has been reported in the literature. Here an unusual suicide method in a 17-year old man by suffocation from covering the face with household plastic wrap, combined....... The deceased was a 17-year old man who was found with the nose and mouth closed with a piece of kitchen plastic wrap. The plastic wrap had been removed prior to autopsy. Autopsy findings were suggestive of asphyxia, but were otherwise negative. Nitrous oxide was detected in the brain and lung tissue...... with headspace-gas chromatography-mass spectrometry (headspace-GCMS). The cause of death was assumed to be suffocation caused by plastic wrap covering the face, combined with nitrous oxide inhalation. Suicide was suspected because of a history of depression for several months. Nitrous oxide, also known...

  9. The integrated nitrous oxide and methane grassland project

    Energy Technology Data Exchange (ETDEWEB)

    Leffelaar, P.A.; Langeveld, C.A.; Hofman, J.E.; Segers, R.; Van den Pol-van Dasselaar, A.; Goudriaan, J.; Rabbinge, R.; Oenema, O. [Department of Theoretical Production Ecology, Wageningen Agricultural University, Wageningen (Netherlands)

    2000-07-01

    The integrated nitrous oxide (N{sub 2}O) and methane (CH{sub 4}) grassland project aims to estimate and explain emissions of these greenhouse gases from two ecosystems, namely drained agricultural peat soil under grass at the experimental farm Zegveld and undrained peat in the nature preserve Nieuwkoopse Plassen, both Netherlands. Peat soils were chosen because of their expected considerable contribution to the greenhouse gas budget considering the prevailing wet and partial anaerobic conditions. The emission dynamics of these ecosystems are considered representatives of large peat areas because the underlying processes are rather general and driven by variables like organic matter characteristics, water and nutrient conditions and type of vegetation. The research approach comprises measurements and modelling at different integration levels relating to the microbiology of the production and consumption of N{sub 2}O and CH{sub 4} (laboratory studies), their movement through peat soil (rhizolab and field studies), and the resulting fluxes (field studies). Typical emissions from drained soil were 15-40 kg ha{sup -1} y{sup -1} N{sub 2}O and virtually zero for CH{sub 4}. The undrained soil in the nature preserve emitted 100-280 kg ha{sup -1} y{sup -1} CH{sub 4}, and probably little N{sub 2}O. The process knowledge, collected and partly integrated in the models, helps to explain these data. For example, the low methane emission from drained peat can more coherently be understood and extrapolated because: (1) upper soil layers are aerobic, thus limiting methane production and stimulating methane oxidation, (2) absence of aerenchymatous roots of wetland plants that connect deeper anaerobic soil layers where methane is produced to the atmosphere and supply labile carbon, (3) a low methane production potential in deep layers due to the low decomposability of organic matter, and (4) long anaerobic periods needed in the topsoil to develop a methane production potential. This

  10. Continuous measurements of nitrous oxide isotopomers during incubation experiments

    Science.gov (United States)

    Winther, Malte; Balslev-Harder, David; Christensen, Søren; Priemé, Anders; Elberling, Bo; Crosson, Eric; Blunier, Thomas

    2018-02-01

    Nitrous oxide (N2O) is an important and strong greenhouse gas in the atmosphere. It is produced by microbes during nitrification and denitrification in terrestrial and aquatic ecosystems. The main sinks for N2O are turnover by denitrification and photolysis and photo-oxidation in the stratosphere. In the linear N = N = O molecule 15N substitution is possible in two distinct positions: central and terminal. The respective molecules, 14N15N16O and 15N14N16O, are called isotopomers. It has been demonstrated that N2O produced by nitrifying or denitrifying microbes exhibits a different relative abundance of the isotopomers. Therefore, measurements of the site preference (difference in the abundance of the two isotopomers) in N2O can be used to determine the source of N2O, i.e., nitrification or denitrification. Recent instrument development allows for continuous position-dependent δ15N measurements at N2O concentrations relevant for studies of atmospheric chemistry. We present results from continuous incubation experiments with denitrifying bacteria, Pseudomonas fluorescens (producing and reducing N2O) and Pseudomonas chlororaphis (only producing N2O). The continuous measurements of N2O isotopomers reveals the transient isotope exchange among KNO3, N2O, and N2. We find bulk isotopic fractionation of -5.01 ‰ ± 1.20 for P. chlororaphis, in line with previous results for production from denitrification. For P. fluorescens, the bulk isotopic fractionation during production of N2O is -52.21 ‰ ± 9.28 and 8.77 ‰ ± 4.49 during N2O reduction.The site preference (SP) isotopic fractionation for P. chlororaphis is -3.42 ‰ ± 1.69. For P. fluorescens, the calculations result in SP isotopic fractionation values of 5.73 ‰ ± 5.26 during production of N2O and 2.41 ‰ ± 3.04 during reduction of N2O. In summary, we implemented continuous measurements of N2O isotopomers during incubation of denitrifying bacteria and believe that similar experiments will lead to a better

  11. Inhalation analgesia with nitrous oxide versus other analgesic techniques in hysteroscopic polypectomy: a pilot study.

    Science.gov (United States)

    Del Valle Rubido, Cristina; Solano Calvo, Juan Antonio; Rodríguez Miguel, Antonio; Delgado Espeja, Juan José; González Hinojosa, Jerónimo; Zapico Goñi, Álvaro

    2015-01-01

    To show the decrease in pain and better tolerance to inhalation analgesia with a 50% equimolar mixture of nitrogen protoxide and oxygen in hysteroscopic polypectomy compared with paracervical anesthesia and a control group. One hundred six patients scheduled for office hysteroscopy and polypectomy were divided into the following 3 groups: the control group, the nitrous oxide group, and the paracervical infiltration group. Patients were assigned sequentially (Canadian Task Force classification II-1). The study took place in a hysteroscopy outpatient clinic under the supervision of a gynecologist and 2 nurses trained to cooperate in the trial. One hundred six women from Area III of Madrid Community, Spain, who had been diagnosed with endometrial polyps at a gynecology office and were scheduled for office hysteroscopy and polypectomy agreed to participate in the study. Patients in group 1 (control group) received no treatment. Group 2 received inhaled nitrous oxide and group 3 paracervical infiltration with 1% lidocaine. Pain was assessed using the visual analog scale (0-10). Pain perceived by patients was lower in the nitrous Oxide group (mean: 3.55 ± 0.60, median: 3) versus the control group (mean: 5.49 ± 1.88, median: 6, p nitrous oxide group, and good for the paracervical infiltration group (p nitrous oxide group, whereas in the paracervical infiltration group, there were complications in more than 50% of the patients. No severe complications occurred. Nitrous oxide is a safe and effective analgesic technique for polipectomy office hysteroscopy compared with the paracervical infiltration and control groups. Copyright © 2015 AAGL. Published by Elsevier Inc. All rights reserved.

  12. Investigating the effects of nitrous oxide sedation on frontal-parietal interactions.

    Science.gov (United States)

    Ryu, Ji-Ho; Kim, Pil-Jong; Kim, Hong-Gee; Koo, Yong-Seo; Shin, Teo Jeon

    2017-06-09

    Although functional connectivity has received considerable attention in the study of consciousness, few studies have investigated functional connectivity limited to the sedated state where consciousness is maintained but impaired. The aim of the present study was to investigate changes in functional connectivity of the parietal-frontal network resulting from nitrous oxide-induced sedation, and to determine the neural correlates of cognitive impairment during consciousness transition states. Electroencephalography was acquired from healthy adult patients who underwent nitrous oxide inhalation to induce cognitive impairment, and was analyzed using Granger causality (GC). Periods of awake, sedation and recovery for GC between frontal and parietal areas in the delta, theta, alpha, beta, gamma and total frequency bands were obtained. The Friedman test with post-hoc analysis was conducted for GC values of each period for comparison. As a sedated state was induced by nitrous oxide inhalation, power in the low frequency band showed increased activity in frontal regions that was reversed with discontinuation of nitrous oxide. Feedback and feedforward connections analyzed in spectral GC were changed differently in accordance with EEG frequency bands in the sedated state by nitrous oxide administration. Calculated spectral GC of the theta, alpha, and beta frequency regions in the parietal-to-frontal direction was significantly decreased in the sedated state while spectral GC in the reverse direction did not show significant change. Frontal-parietal functional connectivity is significantly affected by nitrous oxide inhalation. Significantly decreased parietal-to-frontal interaction may induce a sedated state. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Nitrous oxide emissions and denitrification rates: A blueprint for smart management and remediation of agricultural landscapes.

    Science.gov (United States)

    Tomasek, A.; Hondzo, M.; Kozarek, J. L.

    2015-12-01

    Anthropogenic activities have greatly altered the global nitrogen cycle, especially in the agriculturally dominated Midwest, with severe consequences on human and aquatic health. Complete microbial denitrification can be viewed as a nitrogen sink, converting soluble nitrate into inert nitrogen gas. This research aims to quantify and correlate the driving parameters in microbial denitrification and explore the relationship to the abundance of denitrifying genes and the microbial communities at these sites. Denitrifying genes for each step in the denitrification process have been quantified. Data from a field site in Southern Minnesota has been collected throughout the season for two years enabling investigation into the temporal variability of denitrification. Data was collected at two cross-sections across the channel to determine the effect of bank location and moisture content on denitrification. Data were collected in an experimental basin in the summer of 2015 to determine the effect of flooding and benthic organic matter content and quality on microbial denitrification and nitrous oxide production. Four sediment types were investigated in three different flood regimes. After each raising or lowering of the water level, soil cores were taken to determine soil characteristics, the potential denitrification using the denitrification enzyme activity method, nitrous oxide production using a static core method, and the denitrifying gene abundance. Chambers were also deployed over each soil amendment in each flood regime to determine the nitrous oxide production over time. Results from these studies will convey a more complete explanation of denitrification and nitrous oxide production under varying environmental conditions. By determining the driving parameters for microbial denitrification, denitrification hot spots and hot moments can be created and enhanced. One potential consequence of increased denitrification is the possibility of incomplete denitrification

  14. Nitrous oxide provides safe and effective analgesia for minor paediatric procedures - a systematic review

    DEFF Research Database (Denmark)

    Pedersen, Rie S; Bayat, Allan; Steen, Nick Phaff

    2013-01-01

    Pain and distress during minor hospital-related procedures is a familiar problem in many children. Inadequate relief of children's procedural pain and distress not only affects the experience of the children and their parents, but also adversely impacts procedural success. We aimed to review the ...... the safety and efficacy of nitrous oxide during brief, but painful paediatric procedures and to compare nitrous oxide with some of the commonly used pharmacological and non-pharmacological treatments for relieving anxiety and mild to moderate pain in Denmark....

  15. Nitrous oxide production and consumption potential in an agricultural and a forest soil

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    Both a laboratory incubation experiment using soils from an agricultural field and a forest and field measurements at the same locations were conducted to determine nitrous oxide (N2O) production and consumption (reduction) potentials using the acetylene (C2H2) inhibition technique. Results from...... measurements show that average N2O emission rates were 0.56 and 0.59 kg N ha-1 in the agricultural field and forest, respectively. When C2H2 was provided in the field measurements, N2O emission rates from the agricultural field and forest increased by 38 and 51%, respectively. Nitrous oxide consumption under...

  16. Bending localization of nitrous oxide under anharmonicity and Fermi coupling: the dynamical potential approach

    International Nuclear Information System (INIS)

    Zhang Chi; Wu Guo-Zhen; Fang Chao

    2010-01-01

    This paper studies the vibrational nonlinear dynamics of nitrous oxide with Fermi coupling between the symmetric stretching and bending coordinates by classical dynamical potential approach. This is a global approach in the sense that the overall dynamics is evidenced by the classical nonlinear variables such as the fixed points and the focus are on a set of levels instead of individual ones. The dynamics of nitrous oxide is demonstrated to be not so much dependent on the excitation energy. Moreover, the localized bending mode is shown to be ubiquitous in all the energy range studied

  17. Homocysteine levels after nitrous oxide anesthesia for living-related donor renal transplantation: a randomized, controlled, double-blind study.

    Science.gov (United States)

    Coskunfirat, N; Hadimioglu, N; Ertug, Z; Akbas, H; Davran, F; Ozdemir, B; Aktas Samur, A; Arici, G

    2015-03-01

    Nitrous oxide anesthesia increases postoperative homocysteine concentrations. Renal transplantation candidates present with higher homocysteine levels than patients with no renal disease. We designed this study to investigate if homocysteine levels are higher in subjects receiving nitrous oxide for renal transplantation compared with subjects undergoing nitrous oxide free anesthesia. Data from 59 patients scheduled for living-related donor renal transplantation surgery were analyzed in this randomized, controlled, blinded, parallel-group, longitudinal trial. Patients were assigned to receive general anesthesia with (flowmeter was set at 2 L/min nitrous oxide and 1 L/min oxygen) or without nitrous oxide (2 L/min air and 1 L/min oxygen). We evaluated levels of total homocysteine and known determinants, including creatinine, folate, vitamin B12, albumin, and lipids. We evaluated factor V and von Willebrand factor (vWF) to determine endothelial dysfunction and creatinine kinase myocardial band (CKMB)-mass, troponin T to show myocardial ischemia preoperatively in the holding area (T1), after discontinuation of anesthetic gases (T2), and 24 hours after induction (T3). Compared with baseline, homocysteine concentrations significantly decreased both in the nitrous oxide (22.3 ± 16.3 vs 11.8 ± 9.9; P nitrous oxide-free groups (21.5 ± 15.3 vs 8.0 ± 5.7; P nitrous oxide group had significantly higher mean plasma homocysteine concentrations than the nitrous oxide-free group (P = .021). The actual homocysteine difference between groups was 3.8 μmol/L. This study shows that homocysteine levels markedly decrease within 24 hours after living-related donor kidney transplantation. Patients receiving nitrous oxide have a lesser reduction, but this finding is unlikely to have a clinical relevance. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Sources of nitrous oxide emitted from European forest soils

    Directory of Open Access Journals (Sweden)

    P. Ambus

    2006-01-01

    Full Text Available Forest ecosystems may provide strong sources of nitrous oxide (N2O, which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great uncertainties. In this study, we have investigated the quantitative and qualitative relationships between N-cycling and N2O production in European forests in order to evaluate the importance of nitrification and denitrification for N2O production. Soil samples were collected in 11 different sites characterized by variable climatic regimes and forest types. Soil N-cycling and associated production of N2O was assessed following application of 15N-labeled nitrogen. The N2O emission varied significantly among the different forest soils, and was inversely correlated to the soil C:N ratio. The N2O emissions were significantly higher from the deciduous soils (13 ng N2O-N cm-3 d-1 than from the coniferous soils (4 ng N2O-N cm-3 d-1. Nitrate (NO3- was the dominant substrate for N2O with an average contribution of 62% and exceeding 50% at least once for all sites. The average contribution of ammonium (NH4+ to N2O averaged 34%. The N2O emissions were correlated with gross nitrification activities, and as for N2O, gross nitrification was also higher in deciduous soils (3.4 µg N cm-3 d-1 than in coniferous soils (1.1 µg N cm-3 d-1. The ratio between N2O production and gross nitrification averaged 0.67% (deciduous and 0.44% (coniferous. Our study suggests that changes in forest composition in response to land use activities and global change may have implications for regional budgets of greenhouse gases. From the study it also became clear that N2O emissions were driven by the nitrification activity, although the N2O was produced per se mainly from denitrification. Increased nitrification in response to accelerated N inputs predicted for forest ecosystems in Europe may

  19. Permafrost Thaw increases Emissions of Nitrous Oxide from Subarctic Peatlands

    Science.gov (United States)

    Voigt, C.; Marushchak, M. E.; Lamprecht, R. E.; Jackowicz-Korczynski, M.; Lindgren, A.; Mastepanov, M.; Christensen, T. R.; Granlund, L.; Tahvanainen, T.; Martikainen, P. J.; Biasi, C.

    2017-12-01

    Permafrost soils in the Arctic are thawing, exposing not only carbon but also large nitrogen stocks. The decomposition of this vast pool of long-term immobile C and N stocks results in the release of greenhouse gases to the atmosphere. Among these, carbon dioxide (CO2) and methane (CH4) are being studied extensively, and gaseous C release from thawing permafrost is known to be substantial. Most recent studies, however, show that Arctic soils may further be a relevant source of the strong greenhouse gas nitrous oxide (N2O). As N2O is almost 300 times more powerful in warming the climate than CO2 based on a 100-yr time horizon, the release of N2O from thawing permafrost could create a significant non-carbon permafrost-climate feedback. To study the effect of permafrost thaw on N2O fluxes, we collected peat mesocosms from a Subarctic permafrost peatland, and subjected these intact soil-plant systems to sequential thawing from the top of the active layer down to the upper permafrost layer. Measurements of N2O fluxes were coupled with detailed soil analyses and process studies. Since N2O fluxes are highly dependent on moisture conditions and vegetation cover, we applied two distinct moisture treatments (dry vs. wet) and simulated permafrost thaw in vegetated as well as in naturally bare mesocosms. Under dry conditions, permafrost thaw clearly increased N2O emissions. We observed the largest post-thaw emissions from bare peat surfaces, a typical landform in subarctic peatlands previously identified as hot spots for Arctic N2O emissions. There, permafrost thaw caused a five-fold increase in emissions (0.56 vs. 2.81 mg N2O m-2 d-1). While water-logged conditions suppressed N2O emissions, the presence of vegetation lowered, but did not prevent post-thaw N2O release. Based on these findings, we show that one fourth of the Arctic land area could be vulnerable for N2O emissions when permafrost thaws. Our results demonstrate that Arctic N2O emissions may be larger than

  20. Hydrothermal oxidation of ammonia/organic waste mixtures

    International Nuclear Information System (INIS)

    Luan, Li; Proesmans, P.I.; Buelow, S.J.

    1997-01-01

    Hydrothermal oxidation is a promising new technology for the treatment of radioactive contaminated hazardous organic wastes. Los Alamos National Laboratory is currently evaluating this technology for the U. S. Department of Energy. In this paper, we present experimental results from the study of the hydrothermal oxidation of an ammonia/alcohol/uranium waste mixture. The use of a co-oxidant system consisting of hydrogen peroxide combined with nitrate is discussed. Experiments demonstrate near complete destruction of ammonia and organic compounds at 500 degrees C, 38 MPa, and 50 seconds reaction time. The ammonia and total organic carbon (TOC) concentrations in a waste simulant is reduced from 8,500 mg/L of ammonia and 12,500 mg/L TOC to 30 mg/L ammonia and less than 10 mg/L TOC. The major reaction products are CO 2 , N 2 , and a small amount of N 2 O. Comparison experiments with nitrate and hydrogen peroxide used individually show the advantage of the co-oxidant system

  1. Nitrous Oxide and Serious Long-term Morbidity and Mortality in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II Trial.

    Science.gov (United States)

    Leslie, Kate; Myles, Paul S; Kasza, Jessica; Forbes, Andrew; Peyton, Philip J; Chan, Matthew T V; Paech, Michael J; Sessler, Daniel I; Beattie, W Scott; Devereaux, P J; Wallace, Sophie

    2015-12-01

    The Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial randomly assigned 7,112 noncardiac surgery patients at risk of perioperative cardiovascular events to 70% N2O or 70% N2 groups. The aim of this follow-up study was to determine the effect of nitrous oxide on a composite primary outcome of death and major cardiovascular events at 1 yr after surgery. One-year follow-up was conducted via a medical record review and telephone interview. Disability was defined as a Katz index of independence in activities of daily living score less than 8. Adjusted odds ratios and hazard ratios were calculated as appropriate for primary and secondary outcomes. Among 5,844 patients evaluated at 1 yr, 435 (7.4%) had died, 206 (3.5%) had disability, 514 (8.8%) had a fatal or nonfatal myocardial infarction, and 111 (1.9%) had a fatal or nonfatal stroke during the 1-yr follow-up period. Exposure to nitrous oxide did not increase the risk of the primary outcome (odds ratio, 1.08; 95% CI, 0.94 to 1.25; P = 0.27), disability or death (odds ratio, 1.07; 95% CI, 0.90 to 1.27; P = 0.44), death (hazard ratio, 1.17; 95% CI, 0.97 to 1.43; P = 0.10), myocardial infarction (odds ratio, 0.97; 95% CI, 0.81 to 1.17; P = 0.78), or stroke (odds ratio, 1.08; 95% CI, 0.74 to 1.58; P = 0.70). These results support the long-term safety of nitrous oxide administration in noncardiac surgical patients with known or suspected cardiovascular disease.

  2. Fluxed of nitrous oxide and methane in a lake border ecosystem in northern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Rusch, H.; Rembges, D.; Papke, H.; Rennenberg, H. [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

    1995-12-31

    Methane and nitrous oxide are radiatively active trace gases. This accounts for approximately 20 % of the total anticipated greenhouse effect. The atmospheric mixing ratio of both gases has increased significantly during the last decades at a rate of 0.25 % yr{sup -l} for N{sub 2}O and a rate of 1 % yr{sup -1} for CH{sub 4}. Whether this increase is caused by enhanced biogenic production of both gases or is due to decreased global sinks, has not been definitely elucidated. Soils are an important source of methane and nitrous oxide. Natural wetlands, e.g., have a similar global source strength of methane as rice paddies. On the other hand, well aerated grasslands have been shown to be a sink for atmospheric methane due to methane oxidation. Nitrous oxide is emitted by a wide range of soil types. Its rate of emission is strongly enhanced by nitrogen fertilization. In the present study, fluxes of methane and nitrous oxide were determined in a lake border ecosystem along a toposequence from reed to dry pasture. The aim of this study was to characterize the influence of soil type, land use and season on the flux rates of these greenhouse gases. (author)

  3. Fluxed of nitrous oxide and methane in a lake border ecosystem in northern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Rusch, H; Rembges, D; Papke, H; Rennenberg, H [Fraunhofer Inst. for Atmospheric Environmental Research, Garmisch-Partenkirchen (Germany)

    1996-12-31

    Methane and nitrous oxide are radiatively active trace gases. This accounts for approximately 20 % of the total anticipated greenhouse effect. The atmospheric mixing ratio of both gases has increased significantly during the last decades at a rate of 0.25 % yr{sup -l} for N{sub 2}O and a rate of 1 % yr{sup -1} for CH{sub 4}. Whether this increase is caused by enhanced biogenic production of both gases or is due to decreased global sinks, has not been definitely elucidated. Soils are an important source of methane and nitrous oxide. Natural wetlands, e.g., have a similar global source strength of methane as rice paddies. On the other hand, well aerated grasslands have been shown to be a sink for atmospheric methane due to methane oxidation. Nitrous oxide is emitted by a wide range of soil types. Its rate of emission is strongly enhanced by nitrogen fertilization. In the present study, fluxes of methane and nitrous oxide were determined in a lake border ecosystem along a toposequence from reed to dry pasture. The aim of this study was to characterize the influence of soil type, land use and season on the flux rates of these greenhouse gases. (author)

  4. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    Substrates that contain high ammonia levels can cause inhibition on anaerobic digestion process and unstable biogas production. The aim of the current study was to assess the effects of different ammonia levels on pure strains of (syntrophic acetate oxidizing) SAO bacteria and hydrogenotrophic...... methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

  5. Trace Metal Requirements for Microbial Enzymes Involved in the Production and Consumption of Methane and Nitrous Oxide

    Science.gov (United States)

    Glass, Jennifer B.; Orphan, Victoria J.

    2011-01-01

    Fluxes of greenhouse gases to the atmosphere are heavily influenced by microbiological activity. Microbial enzymes involved in the production and consumption of greenhouse gases often contain metal cofactors. While extensive research has examined the influence of Fe bioavailability on microbial CO2 cycling, fewer studies have explored metal requirements for microbial production and consumption of the second- and third-most abundant greenhouse gases, methane (CH4), and nitrous oxide (N2O). Here we review the current state of biochemical, physiological, and environmental research on transition metal requirements for microbial CH4 and N2O cycling. Methanogenic archaea require large amounts of Fe, Ni, and Co (and some Mo/W and Zn). Low bioavailability of Fe, Ni, and Co limits methanogenesis in pure and mixed cultures and environmental studies. Anaerobic methane oxidation by anaerobic methanotrophic archaea (ANME) likely occurs via reverse methanogenesis since ANME possess most of the enzymes in the methanogenic pathway. Aerobic CH4 oxidation uses Cu or Fe for the first step depending on Cu availability, and additional Fe, Cu, and Mo for later steps. N2O production via classical anaerobic denitrification is primarily Fe-based, whereas aerobic pathways (nitrifier denitrification and archaeal ammonia oxidation) require Cu in addition to, or possibly in place of, Fe. Genes encoding the Cu-containing N2O reductase, the only known enzyme capable of microbial N2O conversion to N2, have only been found in classical denitrifiers. Accumulation of N2O due to low Cu has been observed in pure cultures and a lake ecosystem, but not in marine systems. Future research is needed on metalloenzymes involved in the production of N2O by enrichment cultures of ammonia oxidizing archaea, biological mechanisms for scavenging scarce metals, and possible links between metal bioavailability and greenhouse gas fluxes in anaerobic environments where metals may be limiting due to sulfide

  6. Nitrous oxide production by micromycetes isolated from soils under cattle overwintering husbandry

    Czech Academy of Sciences Publication Activity Database

    Jirout, Jiří; Šimek, Miloslav; Elhottová, Dana

    2013-01-01

    Roč. 4, č. 2 (2013), s. 427 ISSN 2040-4700. [Greenhouse Gases and Animal Agriculture Conference (GGAA 2013) /5./. 23.06.2013-26.06.2013, Dublin] R&D Projects: GA ČR GPP504/12/P752 Institutional support: RVO:60077344 Keywords : nitrous oxide * micromycetes * soils * cattle overwintering husbandry Subject RIV: EE - Microbiology, Virology

  7. Nitrous oxide productivity of soil fungi along a gradient of cattle impact

    Czech Academy of Sciences Publication Activity Database

    Jirout, Jiří

    2015-01-01

    Roč. 17, October (2015), s. 155-163 ISSN 1754-5048 R&D Projects: GA ČR GPP504/12/P752 Institutional support: RVO:60077344 Keywords : soil * fungi * nitrous oxide * selective inhibition * cattle overwintering * oxygen availability Subject RIV: EE - Microbiology, Virology Impact factor: 2.631, year: 2015

  8. Nitrous oxide fluxes and nitrogen cycling along a pasturechronosequence in Central Amazonia, Brazil

    Science.gov (United States)

    B. Wick; E. Veldkamp; W. Z. de Mello; M. Keller; P. Crill

    2005-01-01

    We studied nitrous oxide (N2O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N...

  9. Testing a Conceptual Model of Soil Emissions of Nitrous and Nitric Oxides

    Science.gov (United States)

    Eric A. Davidson; Michael Keller; Heather E. Erickson; Verchot NO-VALUE; Edzo Veldkamp

    2000-01-01

    Nitrous and nitric oxides are often studied separately by atmospheric chemists because they play such different roles in the atmosphere. N2O is a stable greenhouse gas in the lower atmosphere (the troposphere; Ramanathan et al. 1985), but it participates in photochemical reactions in the upper atmosphere (the stratosphere) that destroy ozone (Crutzen 1970). In contrast...

  10. Nitrate leaching and nitrous oxide flux in urban forests and grasslands

    Science.gov (United States)

    Peter M. Groffman; Candiss O. Williams; Richard V. Pouyat; Lawrence E. Band; Ian D. Yesilonis

    2009-01-01

    Urban landscapes contain a mix of land-use types with different patterns of nitrogen (N) cycling and export. We measured nitrate (NO3-) leaching and soil:atmosphere nitrous oxide (N2O) flux in four urban grassland and eight forested long-term study plots in the Baltimore, Maryland metropolitan area....

  11. Nitrous oxide (laughing gas) inhalation as an alternative to electroconvulsive therapy.

    Science.gov (United States)

    Milne, Brian

    2010-05-01

    Electroconvulsive therapy (ECT) is used widely in the treatment of psychiatric conditions; however, its use is not without controversy with some recommending a moratorium on its clinical use. Complications and side effects of ECT include memory loss, injury, problems originating from sympathetic stimulation such as arrhythmias and myocardial ischemia and the risk of general anesthesia. Nitrous oxide (laughing gas) could potentially substitute for ECT as it shares some similar effects, has potential beneficial properties for these psychiatric patients and is relatively safe and easy to administer. Nitrous oxide induces laughter which has been described as nature's epileptoid catharsis which one might surmise would be beneficial for depression. It also produces a central sympathetic stimulation similar to ECT and causes release of endogenous opioid peptides, which are potential candidates for the development of antidepressant drugs. Nitrous oxide is also associated with seizure like activity itself. Administration of nitrous oxide as a substitute for ECT is eminently feasible and could be given in a series of treatments similar to ECT therapy.

  12. Effectiveness of nitrous oxide for postpartum perineal repair: a randomised controlled trial.

    Science.gov (United States)

    Berlit, Sebastian; Tuschy, Benjamin; Brade, Joachim; Mayer, Jade; Kehl, Sven; Sütterlin, Marc

    2013-10-01

    To compare the effectiveness of self-administered 50% nitrous oxide and conventional infiltrative anaesthesia with 1% prilocaine hydrochloride in postpartum perineal repair. A total of 100 women were prospectively enrolled and randomised to receive either infiltrative anaesthesia or a self-administered nitrous oxide mixture (Livopan(©)) for pain relief during postpartum perineal suturing. Besides data concerning anaesthesia, characteristics of patients and labour were documented for statistical analysis. Pain experienced during perineal repair was assessed using the short form of the McGill Pain Questionnaire (SF-MPQ). Forty-eight women received nitrous oxide and 52 underwent perineal suturing after infiltrative anaesthesia. There were no statistically significant differences regarding maternal age, body mass index (BMI), duration of pregnancy and suturing time between the groups. The most frequent birth injury was second-degree perineal laceration in the study group [22/48; 46%] and episiotomy in the control group [18/52; 35%]. Pain experienced during genital tract suturing and patients' satisfaction showed no statistically significant differences between the groups. Thirty-seven women in the study group and 47 in the control group were satisfied with the anaesthesia during perineal repair and would recommend it to other parturients [37/48, 77% vs. 47/52, 90%; p=0.0699). Nitrous oxide self-administration during genital tract suturing after vaginal childbirth is a satisfactory and effective alternative to infiltrative anaesthesia. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  13. Nitrous Oxide Emissions from a Large, Impounded River: The Ohio River

    Science.gov (United States)

    Models suggest that microbial activity in streams and rivers is a globally significant source of anthropogenic nitrous oxide (N2O), a potent greenhouse gas and the leading cause of stratospheric ozone destruction. However, model estimates of N2O emissions are poorly constrained ...

  14. Dynamic modelling of nitrous oxide emissions from three Swedish sludge liquor treatment systems

    DEFF Research Database (Denmark)

    Lindblom, E.; Arnell, M.; Flores-Alsina, X.

    2016-01-01

    The objective of this paper is to model the dynamics and validate the results of nitrous oxide (N2O)emissions from three Swedish nitrifying/denitrifying, nitritation and anammox systems treating real anaerobic digester sludge liquor. The Activated Sludge Model No. 1 is extended to describe N2O...

  15. Temporal nitrous oxide emissions from beef cattle feedlot manure following a simulated rainfall event

    Science.gov (United States)

    A pilot-scale, recirculating-flow-through, non-steady-state (RFT-NSS) chamber system was designed for quantifying nitrous oxide (N2O) emissions from simulated open-lot beef cattle feedlot pens. The system employed five 1 square meter steel pans. A lid was placed systematically on each pan and heads...

  16. Controls on nitrous oxide production and consumption in reservoirs of the Ohio River Basin

    Science.gov (United States)

    Aquatic ecosystems are a globally significant source of nitrous oxide (N2O), a potent greenhouse gas, but estimates are largely based on studies conducted in streams and rivers with relatively less known about N2O dynamics in lakes and reservoirs. Due to long water residence tim...

  17. Predicting nitrous oxide emissions from manure properties and soil moisture: An incubation experiment

    DEFF Research Database (Denmark)

    Baral, Khagendra Raj; Arthur, Emmanuel; Olesen, Jørgen Eivind

    2016-01-01

    Field-applied manure is a source of essential plant nutrients, but benefits may be partly offset by high rates of nitrous oxide (N2O) emissions, as modified by manure characteristics and soil properties. In a 28-d incubation experiment we quantified short-term emissions of N2O from a sandy loam...

  18. Can pine trees act as sources for nitrous oxide (N2O) and methane (CH4)?

    Czech Academy of Sciences Publication Activity Database

    Macháčová, Kateřina; Pihlatie, M.; Vanhatalo, A.; Halmeenmäki, E.; Aaltonen, H.; Kolari, P.; Aalto, J.; Pumpanen, J.; Pavelka, Marian; Acosta, Manuel; Urban, Otmar; Bäck, J.

    2013-01-01

    Roč. 142, č. 2013 (2013), s. 362-366. ISBN 952-5027-76-7. ISSN 0784-3496 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : methane * nitrous oxide * scots pine * transport Subject RIV: EH - Ecology, Behaviour

  19. Differential effects of nitrous oxide and propofol on myogenic transcranial motor evoked responses during sufentanil anaesthesia

    NARCIS (Netherlands)

    Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Drummond, J. C.

    1997-01-01

    We have compared the effects of 50% nitrous oxide and propofol, each administered concurrently with sufentanil, on the amplitudes and latencies of the compound muscle action potential (CMAP) response to transcranial electrical stimulation. Using a crossover design, 12 patients undergoing spinal

  20. Comparing Nitrous Oxide Emissions from Three Residential Landscapes under Different Management Schemes Following Natural Rainfall Events

    Science.gov (United States)

    Cultural lawn management practices that produce aesthetically appealing landscapes may also create environmental conditions that stimulate soil nitrous oxide (N2O) emissions. The purpose of this study is to investigate the effects of lawn management practices on N2O fluxes from ...

  1. Marine nitrous oxide emissions: An unknown liability for the international water sector

    Science.gov (United States)

    Reliable estimates of anthropogenic greenhouse gas (GHG) emissions are essential for setting effective climate policy at both the sector and national level. Current IPCC Guidelines for calculating nitrous oxide (N2O) emissions from sewage management are both highly uncertain and ...

  2. Spatial variability in nitrous oxide and methane emissions from beef cattle feedyard pen surfaces

    Science.gov (United States)

    Greenhouse gas emissions from beef cattle feedlots include enteric carbon dioxide and methane, and manure-derived methane, nitrous oxide and carbon dioxide. Enteric methane comprises the largest portion of the greenhouse gas footprint of beef cattle feedyards. For the manure component, methane is th...

  3. A geostatistical approach to identify and mitigate agricultural nitrous oxide emission hotspots

    Science.gov (United States)

    Anthropogenic emissions of nitrous oxide (N2O), a trace gas with severe environmental costs, are greatest from agricultural soils amended with nitrogen (N) fertilizer. However, accurate N2O emission estimates at fine spatial scales are made difficult by their high variability, which represents a cr...

  4. NITRATE AND NITROUS OXIDE CONCENTRATIONS IN SMALL STREAMS OF THE GEORGIA PIEDMONT

    Science.gov (United States)

    We are measuring dissolved nitrate and nitrous oxide concentrations and related parameters in 17 headwater streams in the South Fork Broad River, Georgia watershed on a monthly basis. The selected small streams drain watersheds dominated by forest, pasture, residential, or mixed...

  5. NITROUS OXIDE BEHAVIOR IN THE ATMOSPHERE, AND IN COMBUSTION AND INDUSTRIAL SYSTEMS

    Science.gov (United States)

    Tropospheric measurements show that nitrous oxide (N2O) concentrations are increasing over time. This demonstrates the existence of one or more significant anthropogenic sources, a fact that has generated considerable research interest over the last several years. The debate has ...

  6. Nitrous oxide production in sputum from cystic fibrosis patients with chronic Pseudomonas aeruginosa lung infection

    DEFF Research Database (Denmark)

    Kolpen, Mette; Kühl, Michael; Bjarnsholt, Thomas

    2014-01-01

    local anoxia by consuming the majority of O2 for production of reactive oxygen species (ROS). We hypothesized that P. aeruginosa acquires energy for growth in anaerobic endobronchial mucus by denitrification, which can be demonstrated by production of nitrous oxide (N2O), an intermediate...

  7. Nitrous Oxide Production in an Eastern Corn Belt Soil: Sources and Redox Range

    Science.gov (United States)

    Nitrous oxide (N2O) derived from soils is a main contributor to the greenhouse gas effect and a precursor to ozone-depleting substrates; however, the source processes and interacting controls are not well established. This study was conducted to estimate magnitude and source (nitrification vs. denit...

  8. Nitrous oxide production in grassland soils: assessing the contribution of nitrifier denitrification

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Laanbroek, H.J.; Oenema, O.

    2004-01-01

    Nitrifier denitrification is the reduction of NO2- to N2 by nitrifiers. It leads to the production of the greenhouse gas nitrous oxide (N2O) as an intermediate and possible end product. It is not known how important nitrifier denitrification is for the production of N2O in soils. We explored N2O

  9. Nitrous oxide production, its source and distribution in urine patches on grassland on peat soil.

    NARCIS (Netherlands)

    Koops, J.G.; Beusichem, van M.L.; Oenema, O.

    1997-01-01

    Urine patches are considered to be important sites for nitrous oxide (N2O) production through nitrification and denitrification due to their high concentration of nitrogen (N). The aim of the present study was to determine the microbial source and size of production of N2O in different zones of a

  10. Linking organic carbon, water content and nitrous oxide emission in a reclaimed coal mine soil

    Science.gov (United States)

    Manure-based organic amendments can restore soil quality and allow for intensive sustained biomass production on degraded lands. However the large quantities of nitrogen and organic carbon added with such amendments could create soil conditions favorable for nitrous oxide production and emissions. T...

  11. Nitrous oxide (N2O). Emission inventory and options for control in the Netherlands

    NARCIS (Netherlands)

    Kroeze C; LAE

    1994-01-01

    This study was initiated to overview current knowledge on nitrous oxide (N2O). The report reviews atmospheric behaviour of N2O, global sources and sinks, Dutch emissions in 1990, options to reduce emissions, and past and future emissions. Despite the uncertainties involved, it is likely that without

  12. The impact of slurry application technique on nitrous oxide emission from agricultural soils

    NARCIS (Netherlands)

    Velthof, G.L.; Mosquera, J.

    2011-01-01

    Direct nitrous oxide (N2O) emissions from fertilized soils are generally estimated using emission factors. However, the emission factors for N2O emission of applied slurry are not well quantified. The effect of slurry application technique on N2O emission was quantified in field experiments in the

  13. Dissimilatory nitrate reduction to nitrate, nitrous oxide, and ammonium by Pseudomonas putrefaciens.

    Science.gov (United States)

    Samuelsson, M O

    1985-10-01

    The influence of redox potential on dissimilatory nitrate reduction to ammonium was investigated on a marine bacterium, Pseudomonas putrefaciens. Nitrate was consumed (3.1 mmol liter-1), and ammonium was produced in cultures with glucose and without sodium thioglycolate. When sodium thioglycolate was added, nitrate was consumed at a lower rate (1.1 mmol liter-1), and no significant amounts of nitrite or ammonium were produced. No growth was detected in glucose media either with or without sodium thioglycolate. When grown on tryptic soy broth, the production of nitrous oxide paralleled growth. In the same medium, but with sodium thioglycolate, nitrous oxide was first produced during growth and then consumed. Acetylene caused the nitrous oxide to accumulate. These results and the mass balance calculations for different nitrogen components indicate that P. putrefaciens has the capacity to dissimilate nitrate to ammonium as well as to dinitrogen gas and nitrous oxide (denitrification). The dissimilatory pathway to ammonium dominates except when sodium thioglycolate is added to the medium.

  14. Nitrous oxide in the Schelde estuary: production by nitrification and emission to the atmosphere

    NARCIS (Netherlands)

    De Wilde, H.; De Bie, M.J.M.

    2000-01-01

    Concentrations of nitrous oxide (N2O), oxygen, nitrate, and ammonium, as well as nitrification activity were determined along the salinity gradient of the Schelde Estuary, Northwest Europe, in October 1993, March 1994, and July 1996, The entire estuary was always supersaturated with N2O.

  15. The effect of sepsis and short-term exposure to nitrous oxide on the ...

    African Journals Online (AJOL)

    It is recognised that prolonged anaesthesia with nitrous oxide (N20) induces megaloblastic anaemia by oxidising vitamin B12 To determine whether sepsis aggravates the effect of H20 on haemopoiesis 5 patients with severe sepsis, who required surgery and were exposed to short-term (45 - 105 minutes) N20 anaesthesia, ...

  16. EPA/IFP EUROPEAN WORKSHOP ON THE EMISSION ON NITROUS OXIDE FROM FOSSIL FUEL COMBUSTION

    Science.gov (United States)

    The report summarizes the proceedings of an EPA/Institut Francais du Petrole (IFP) cosponsored workshop addressing direct nitrous oxide (N2O) emission from fossil fuel combustion. The third in a series, it was held at the IFP in Rueil-Malmaison, France, on June 1-2, 1988. Increas...

  17. Nitrous Oxide (N2O) emissions from human waste in 1970-2050

    NARCIS (Netherlands)

    Strokal, M.; Kroeze, C.

    2014-01-01

    Nitrous oxide (N2O) is an important contributor to climate change. Human waste is an important source of N2O emissions in several world regions, and its share in global emissions may increase in the future. In this paper we, therefore, address N2O emission from human waste: collected (from treatment

  18. Designing efficient nitrous oxide sampling strategies in agroecosystems using simulation models

    Science.gov (United States)

    Debasish Saha; Armen R. Kemanian; Benjamin M. Rau; Paul R. Adler; Felipe Montes

    2017-01-01

    Annual cumulative soil nitrous oxide (N2O) emissions calculated from discrete chamber-based flux measurements have unknown uncertainty. We used outputs from simulations obtained with an agroecosystem model to design sampling strategies that yield accurate cumulative N2O flux estimates with a known uncertainty level. Daily soil N2O fluxes were simulated for Ames, IA (...

  19. Earthworms can increase nitrous oxide emissions from managed grassland: a field study

    NARCIS (Netherlands)

    Lubbers, I.M.; López González, E.; Hummelink, E.W.J.; Groenigen, van J.W.

    2013-01-01

    Earthworms are important in determining the greenhouse gas (GHG) balance of soils. In laboratory studies they have been shown to increase emissions of the potent GHG nitrous oxide (N2O). Here we test whether these earthworm-induced N2O emissions also occur in the field. We quantified N2O emissions

  20. Corn nitrogen management influences nitrous oxide emissions in drained and undrained soils

    Science.gov (United States)

    Tile-drainage and nitrogen (N) fertilization are important for corn (Zea mays L.) production. To date, no studies have evaluated nitrous oxide (N2O) emissions of single vs. split-N fertilizer application under different soil drainage conditions. The objective of this study was to quantify season-lon...

  1. Biochar's role in mitigating soil nitrous oxide emissions: a review and meta-analysis

    NARCIS (Netherlands)

    Cayuela, M.L.; Zwieten, van L.; Singh, B.P.; Jeffery, S.L.; Roig, A.; Sánchez-Monedero, M.A.

    2014-01-01

    More than two thirds of global nitrous oxide (N2O) emissions originate from soil, mainly associated with the extensive use of nitrogen (N) fertilizers in agriculture. Although the interaction of black carbon with the N cycle has been long recognized, the impact of biochar on N2O emissions has only

  2. Nitrous oxide levels in operating and recovery rooms of Iranian hospitals.

    Science.gov (United States)

    Maroufi, Sh Sadigh; Gharavi, Mj; Behnam, M; Samadikuchaksaraei, A

    2011-01-01

    Nitrous oxide (N(2)O) is the oldest anesthetic in routine clinical use and its occupational exposure is under regulation by many countries. As studies are lacking to demonstrate the status of nitrous oxide levels in operating and recovery rooms of Iranian hospitals, we aimed to study its level in teaching hospitals of Tehran University of Medical Sciences. During a 6-month period, we have measured the shift-long time weighted average concentration of N(2)O in 43 operating and 12 recovery rooms of teaching hospitals of Tehran University of Medical Sciences. The results show that the level of nitrous oxide in all hospitals is higher than the limits set by different countries and anesthetists are at higher risk of exposure. In addition, it was shown that installation of air ventilation could reduce not only the overall exposure level, but also the level of exposure of anesthetists in comparison with other personnel. The high nitrous oxide level in Iranian hospitals necessitates improvement of waste gas evacuation systems and regular monitoring to bring the concentration of this gas into the safe level.

  3. Nitrous oxide emissions from a golf course fairway and rough following application of different nitrogen fertilizers

    Science.gov (United States)

    Nitrous oxide (N2O) is a potent greenhouse gas that destroys stratospheric ozone. There is limited research of golf course N2O emission and the effects of frequent fertilization and irrigation. Three enhanced efficiency nitrogen fertilizers (EENFs) were applied to a Colorado golf course fairway and ...

  4. Nitrous oxide fluxes from grassland in the Netherlands. 1. Statistical analysis of flux-chamber measurements

    NARCIS (Netherlands)

    Velthof, G.L.; Oenema, O.

    1995-01-01

    Accurate estimates of total nitrous oxide (N2O) losses from grasslands derived from flux-chamber measurements are hampered by the large spatial and temporal variability of N2O fluxes from these sites. In this study, four methods for the calculation o

  5. Anti-leukemic potential of methyl-cobalamin inactivation by nitrous oxide

    NARCIS (Netherlands)

    J. Abels; A.C.M. Kroes (Aloys C.M.); A.A.M. Ermens (Anton); J. van Kapel (Jan); M. Schoester (Martijn); L.J.M. Spijkers (L. J M); J. Lindemans (Jan)

    1990-01-01

    textabstractMyelo‐cytotoxicity of extended nitrous oxide (N2O) inhalation was described almost forty years ago and then incidentally applied already with temporary success for suppressing leukemia. In 1948 the accompanying megaloblastic maturation arrest was explained by inactivation of the

  6. Nitrous oxide does not influence operating conditions or postoperative course in colonic surgery

    DEFF Research Database (Denmark)

    Krogh, B; Jørn Jensen, P; Henneberg, S W

    1994-01-01

    We studied 150 patients undergoing elective colonic surgery; they were allocated randomly to undergo artificial ventilation with either air-oxygen or nitrous oxide-oxygen during surgery. Eleven patients were excluded. Preoperative management, surgery and postoperative analgesia were similar in bo...

  7. Nitrous oxide emission hotspots and acidic soil denitrification in a riparian buffer zone

    NARCIS (Netherlands)

    van den Heuvel, R.N.

    2010-01-01

    Nitrous oxide (N2O) is a greenhouse gas with a global warming potential of 296 CO2 equivalents and is involved in the depletion of the ozone layer. Through studies on emission sources it was revealed that natural and agricultural soils are important sources of N2O emissions and are responsible for

  8. Nitrogen loss from grassland on peat soils through nitrous oxide production.

    NARCIS (Netherlands)

    Koops, J.G.; Beusichem, van M.L.; Oenema, O.

    1997-01-01

    Nitrous oxide (N2O) in soils is produced through nitrification and denitrification. The N2O produced is considered as a nitrogen (N) loss because it will most likely escape from the soil to the atmosphere as N2O or N2. Aim of the study was to quantify N2O production in grassland on peat soils in

  9. 2004 Methane and Nitrous Oxide Emissions from Manure Management in South Africa

    Directory of Open Access Journals (Sweden)

    Mokhele Edmond Moeletsi

    2015-03-01

    Full Text Available Manure management in livestock makes a significant contribution towards greenhouse gas emissions in the Agriculture; Forestry and Other Land Use category in South Africa. Methane and nitrous oxide emissions are prevalent in contrasting manure management systems; promoting anaerobic and aerobic conditions respectively. In this paper; both Tier 1 and modified Tier 2 approaches of the IPCC guidelines are utilized to estimate the emissions from South African livestock manure management. Activity data (animal population, animal weights, manure management systems, etc. were sourced from various resources for estimation of both emissions factors and emissions of methane and nitrous oxide. The results show relatively high methane emissions factors from manure management for mature female dairy cattle (40.98 kg/year/animal, sows (25.23 kg/year/animal and boars (25.23 kg/year/animal. Hence, contributions for pig farming and dairy cattle are the highest at 54.50 Gg and 32.01 Gg respectively, with total emissions of 134.97 Gg (3104 Gg CO2 Equivalent. Total nitrous oxide emissions are estimated at 7.10 Gg (2272 Gg CO2 Equivalent and the three main contributors are commercial beef cattle; poultry and small-scale beef farming at 1.80 Gg; 1.72 Gg and 1.69 Gg respectively. Mitigation options from manure management must be taken with care due to divergent conducive requirements of methane and nitrous oxide emissions requirements.

  10. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    DEFF Research Database (Denmark)

    Pihlatie, M.; Rinne, J.; Ambus, P.

    2005-01-01

    Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters...

  11. The catalytic cycle of nitrous oxide reductase - The enzyme that catalyzes the last step of denitrification.

    Science.gov (United States)

    Carreira, Cíntia; Pauleta, Sofia R; Moura, Isabel

    2017-12-01

    The reduction of the potent greenhouse gas nitrous oxide requires a catalyst to overcome the large activation energy barrier of this reaction. Its biological decomposition to the inert dinitrogen can be accomplished by denitrifiers through nitrous oxide reductase, the enzyme that catalyzes the last step of the denitrification, a pathway of the biogeochemical nitrogen cycle. Nitrous oxide reductase is a multicopper enzyme containing a mixed valence CuA center that can accept electrons from small electron shuttle proteins, triggering electron flow to the catalytic sulfide-bridged tetranuclear copper "CuZ center". This enzyme has been isolated with its catalytic center in two forms, CuZ*(4Cu1S) and CuZ(4Cu2S), proven to be spectroscopic and structurally different. In the last decades, it has been a challenge to characterize the properties of this complex enzyme, due to the different oxidation states observed for each of its centers and the heterogeneity of its preparations. The substrate binding site in those two "CuZ center" forms and which is the active form of the enzyme is still a matter of debate. However, in the last years the application of different spectroscopies, together with theoretical calculations have been useful in answering these questions and in identifying intermediate species of the catalytic cycle. An overview of the spectroscopic, kinetics and structural properties of the two forms of the catalytic "CuZ center" is given here, together with the current knowledge on nitrous oxide reduction mechanism by nitrous oxide reductase and its intermediate species. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Nitrous oxide emission by the non-denitrifying, nitrate ammonifier Bacillus licheniformis.

    Science.gov (United States)

    Sun, Yihua; De Vos, Paul; Heylen, Kim

    2016-01-19

    Firmicutes have the capacity to remove excess nitrate from the environment via either denitrification, dissimilatory nitrate reduction to ammonium or both. The recent renewed interest in their nitrogen metabolism has revealed many interesting features, the most striking being their wide variety of dissimilatory nitrate reduction pathways. In the present study, nitrous oxide production from Bacillus licheniformis, a ubiquitous Gram-positive, spore-forming species with many industrial applications, is investigated. B. licheniformis has long been considered a denitrifier but physiological experiments on three different strains demonstrated that nitrous oxide is not produced from nitrate in stoichiometric amounts, rather ammonium is the most important end-product, produced during fermentation. Significant strain dependency in end-product ratios, attributed to nitrite and ammonium, and medium dependency in nitrous oxide production were also observed. Genome analyses confirmed the lack of a nitrite reductase to nitric oxide, the key enzyme of denitrification. Based on the gene inventory and building on knowledge from other non-denitrifying nitrous oxide emitters, hypothetical pathways for nitrous oxide production, involving NarG, NirB, qNor and Hmp, are proposed. In addition, all publically available genomes of B. licheniformis demonstrated similar gene inventories, with specific duplications of the nar operon, narK and hmp genes as well as NarG phylogeny supporting the evolutionary separation of previously described distinct BALI1 and BALI2 lineages. Using physiological and genomic data we have demonstrated that the common soil bacterium B. licheniformis does not denitrify but is capable of fermentative dissimilatory nitrate/nitrite reduction to ammonium (DNRA) with concomitant production of N2O. Considering its ubiquitous nature and non-fastidious growth in the lab, B. licheniformis is a suitable candidate for further exploration of the actual mechanism of N2O

  13. Low nitrous oxide production through nitrifier-denitrification in intermittent-feed high-rate nitritation reactors.

    Science.gov (United States)

    Su, Qingxian; Ma, Chun; Domingo-Félez, Carlos; Kiil, Anne Sofie; Thamdrup, Bo; Jensen, Marlene Mark; Smets, Barth F

    2017-10-15

    Nitrous oxide (N 2 O) production from autotrophic nitrogen conversion processes, especially nitritation systems, can be significant, requires understanding and calls for mitigation. In this study, the rates and pathways of N 2 O production were quantified in two lab-scale sequencing batch reactors operated with intermittent feeding and demonstrating long-term and high-rate nitritation. The resulting reactor biomass was highly enriched in ammonia-oxidizing bacteria, and converted ∼93 ± 14% of the oxidized ammonium to nitrite. The low DO set-point combined with intermittent feeding was sufficient to maintain high nitritation efficiency and high nitritation rates at 20-26 °C over a period of ∼300 days. Even at the high nitritation efficiencies, net N 2 O production was low (∼2% of the oxidized ammonium). Net N 2 O production rates transiently increased with a rise in pH after each feeding, suggesting a potential effect of pH on N 2 O production. In situ application of 15 N labeled substrates revealed nitrifier denitrification as the dominant pathway of N 2 O production. Our study highlights operational conditions that minimize N 2 O emission from two-stage autotrophic nitrogen removal systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Crystallographic studies with xenon and nitrous oxide provide evidence for protein-dependent processes in the mechanisms of general anesthesia.

    Science.gov (United States)

    Abraini, Jacques H; Marassio, Guillaume; David, Helene N; Vallone, Beatrice; Prangé, Thierry; Colloc'h, Nathalie

    2014-11-01

    The mechanisms by which general anesthetics, including xenon and nitrous oxide, act are only beginning to be discovered. However, structural approaches revealed weak but specific protein-gas interactions. To improve knowledge, we performed x-ray crystallography studies under xenon and nitrous oxide pressure in a series of 10 binding sites within four proteins. Whatever the pressure, we show (1) hydrophobicity of the gas binding sites has a screening effect on xenon and nitrous oxide binding, with a threshold value of 83% beyond which and below which xenon and nitrous oxide, respectively, binds to their sites preferentially compared to each other; (2) xenon and nitrous oxide occupancies are significantly correlated respectively to the product and the ratio of hydrophobicity by volume, indicating that hydrophobicity and volume are binding parameters that complement and oppose each other's effects; and (3) the ratio of occupancy of xenon to nitrous oxide is significantly correlated to hydrophobicity of their binding sites. These data demonstrate that xenon and nitrous oxide obey different binding mechanisms, a finding that argues against all unitary hypotheses of narcosis and anesthesia, and indicate that the Meyer-Overton rule of a high correlation between anesthetic potency and solubility in lipids of general anesthetics is often overinterpreted. This study provides evidence that the mechanisms of gas binding to proteins and therefore of general anesthesia should be considered as the result of a fully reversible interaction between a drug ligand and a receptor as this occurs in classical pharmacology.

  15. Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

    Science.gov (United States)

    Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

    2013-04-01

    Urban activities generate solid and liquid waste, and the handling and aftercare of the waste results in the emission of various compounds into the surrounding environment. Some of these compounds are emitted as gasses into the atmosphere, including methane and nitrous oxide. Methane and nitrous oxide are strong greenhouse gases and are considered to have 25 and 298 times the greenhouse gas potential of carbon dioxide on a hundred years term (Solomon et al. 2007). Global observations of both gasses have shown increasing concentrations that significantly contribute to the greenhouse gas effect. Methane and nitrous oxide are emitted from both natural and anthropogenic sources and inventories of source specific fugitive emissions from the anthropogenic sources of methane and nitrous oxide of are often estimated on the basis of modeling and mass balance. Though these methods are well-developed, actual measurements for quantification of the emissions is a very useful tool for verifying the modeling and mass balance as well as for validation initiatives done for lowering the emissions of methane and nitrous oxide. One approach to performing such measurements is the tracer dilution method (Galle et al. 2001, Scheutz et al. 2011), where the exact location of the source is located and a tracer gas is released at this source location at a known flow. The ratio of downwind concentrations of the tracer gas and the methane and nitrous oxide gives the emissions rates of the greenhouse gases. This tracer dilution method can be performed using both stationary and mobile measurements and in both cases, real-time measurements of both tracer and quantified gas are required, placing high demands on the analytical detection method. To perform the methane and nitrous oxide measurements, two robust instruments capable of real-time measurements were used, based on cavity ring-down spectroscopy and operating in the near-infrared spectral region. One instrument measured the methane and

  16. Study for drifts of the oxidation in nitrous oxide of an activated coal

    International Nuclear Information System (INIS)

    Diaz Velasquez; Jose de Jesus; Carballo Suarez, Luis M; Freitas, Madalena; Farias, Joaquim Luis Faria; Figueiredo, Jose Luis

    2001-01-01

    In order to obtain materials with different surface properties, an activated carbon was modified by thermal treatment with 20% of nitrous oxide in nitrogen at 500 centigrade degrees, for different periods of time, and also with 5 % of oxygen in nitrogen at 425 centigrade degrees for 600 minutes and 100% of hydrogen at 950 centigrade degrees for 360 minutes. Drifts were used to characterize the surface chemistry of the material treated. The qualitative result s show that the treatments with N2O have larger effects on the intensity of the surface groups. These changes could be associated to the incorporation of nitrogen into the carbon matrix. In agreement with literature reports, it could be said that the gas phase oxidation of the activated carbon shows mainly superficial groups such as carboxylic anhydrides, phenols and carboxylates, lactones and quinones

  17. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; De Boer, W.; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous

  18. Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant

    International Nuclear Information System (INIS)

    Cinti, Giovanni; Frattini, Domenico; Jannelli, Elio; Desideri, Umberto; Bidini, Gianni

    2017-01-01

    Highlights: • An innovative NH 3 production plant was designed. • CO 2 emissions and energy consumption are studied in three different designs. • High temperature electrolysis allows to achieve high efficiency and heat recovery. • The coupling permits storage of electricity into a liquid carbon free chemical. - Abstract: Ammonia is one of the most produced chemicals worldwide and is currently synthesized using nitrogen separated from air and hydrogen from natural gas reforming with consequent high consumption of fossil fuel and high emission of CO 2 . A renewable path for ammonia production is desirable considering the potential development of ammonia as energy carrier. This study reports design and analysis of an innovative system for the production of green ammonia using electricity from renewable energy sources. This concept couples Solid Oxide Electrolysis (SOE), for the production of hydrogen, with an improved Haber Bosch Reactor (HBR), for ammonia synthesis. An air separator is also introduced to supply pure nitrogen. SOE operates with extremely high efficiency recovering high temperature heat from the Haber-Bosch reactor. Aspen was used to develop a model to study the performance of the plant. Both the SOE and the HBR operate at 650 °C. Ammonia production with zero emission of CO 2 can be obtained with a reduction of 40% of power input compared to equivalent plants.

  19. Oxygen concentrators performance with nitrous oxide at 50:50 volume

    Directory of Open Access Journals (Sweden)

    Jorge Ronaldo Moll

    2014-06-01

    Full Text Available Background and objectives: Few investigations have addressed the safety of oxygen from concentrators for use in anesthesia in association with nitrous oxide. This study evaluated the percent of oxygen from a concentrator in association with nitrous oxide in a semi-closed rebreathing circuit. Methods: Adult patients undergoing low risk surgery were randomly allocated into two groups, receiving a fresh gas flow of oxygen from concentrators (O293 or of oxygen from concentrators and nitrous oxide (O293N2O. The fraction of inspired oxygen and the percentage of oxygen from fresh gas flow were measured every 10 min. The ratio of FiO2/oxygen concentration delivered was compared at various time intervals and between the groups. Results: Thirty patients were studied in each group. There was no difference in oxygen from concentrators over time for both groups, but there was a significant improvement in the FiO2 (p < 0.001 for O293 group while a significant decline (p < 0.001 for O293N2O. The FiO2/oxygen ratio varied in both groups, reaching a plateau in the O293 group. Pulse oximetry did not fall below 98.5% in either group. Conclusion: The FiO2 in the mixture of O293 and nitrous oxide fell during the observation period although oxygen saturation was higher than 98.5% throughout the study. Concentrators can be considered a stable source of oxygen for use during short anesthetic procedures, either pure or in association with nitrous oxide at 50:50 volume.

  20. Ammonia oxidation at high pressure and intermediate temperatures

    DEFF Research Database (Denmark)

    Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt

    2016-01-01

    Ammonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under...... oxidizing conditions the onset temperature for reaction was 850–875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH3 at 875 K. The products of reaction were N2 and N2O, while NO and NO2 concentrations were below the detection limit even under oxidizing conditions. The data...... was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3⟶+OH NH2⟶+HO2,NO2 H2NO⟶+O2 HNO⟶+O2 NO ⟶+NH2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH...

  1. Inhibition of bacterial ammonia oxidation by organohydrazines in soil microcosms

    Directory of Open Access Journals (Sweden)

    Yucheng eWu

    2012-01-01

    Full Text Available Hydroxylamine oxidation by hydroxylamine oxidoreductase (HAO is a key step for energy-yielding in support of the growth of ammonia-oxidizing bacteria (AOB. Organohydrazines have been shown to inactivate HAO from Nitrosomonas europaea, and may serve as selective inhibitors to differentiate bacterial from archaeal ammonia oxidation due to the absence of bacterial HAO gene homologue in known ammonia-oxidizing archaea (AOA. In this study, the effects of three organohydrazines on activity, abundance and composition of AOB and AOA were evaluated in soil microcosms. The results indicate that phenylhydrazine and methylhydrazine at the concentration of 100 mol per gram dry weight soil completely suppressed the activity of soil nitrification. DGGE fingerprinting and sequencing analysis of bacterial ammonia monooxygenase subunit A gene (amoA clearly demonstrated that nitrification activity change is well paralleled with the growth of Nitrosomonas europaea-like AOB in soil microcosms. No significant correlation between AOA community structure and nitrification activity was observed among all treatments during the incubation period, although incomplete inhibition of nitrification activity occurred in 2-hydroxyethylhydrazine-amended soil microcosms. These findings show that the HAO-targeted organohydrazines can effectively inhibit bacterial nitrification in soil, and the mechanism of organohydrazine affecting AOA remains unclear.

  2. Ammonia-oxidizing bacteria: A model for molecular microbial ecology

    NARCIS (Netherlands)

    Kowalchuk, G.A.; Stephen, J.R.

    2001-01-01

    The eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. Chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important

  3. Nitrite accumulation from simultaneous free-ammonia and free-nitrous-acid inhibition and oxygen limitation in a continuous-flow biofilm reactor.

    Science.gov (United States)

    Park, Seongjun; Chung, Jinwook; Rittmann, Bruce E; Bae, Wookeun

    2015-01-01

    To achieve nitrite accumulation for shortcut biological nitrogen removal (SBNR) in a biofilm process, we explored the simultaneous effects of oxygen limitation and free ammonia (FA) and free nitrous acid (FNA) inhibition in the nitrifying biofilm. We used the multi-species nitrifying biofilm model (MSNBM) to identify conditions that should or should not lead to nitrite accumulation, and evaluated the effectiveness of those conditions with experiments in continuous flow biofilm reactors (CFBRs). CFBR experiments were organized into four sets with these expected outcomes based on the MSNBM as follows: (i) Control, giving full nitrification; (ii) oxygen limitation, giving modest long-term nitrite build up; (iii) FA inhibition, giving no long-term nitrite accumulation; and (iv) FA inhibition plus oxygen limitation, giving major long-term nitrite accumulation. Consistent with MSNBM predictions, the experimental results showed that nitrite accumulated in sets 2-4 in the short term, but long-term nitrite accumulation was maintained only in sets 2 and 4, which involved oxygen limitation. Furthermore, nitrite accumulation was substantially greater in set 4, which also included FA inhibition. However, FA inhibition (and accompanying FNA inhibition) alone in set 3 did not maintained long-term nitrite accumulation. Nitrite-oxidizing bacteria (NOB) activity batch tests confirmed that little NOB or only a small fraction of NOB were present in the biofilms for sets 4 and 2, respectively. The experimental data supported the previous modeling results that nitrite accumulation could be achieved with a lower ammonium concentration than had been required for a suspended-growth process. Additional findings were that the biofilm exposed to low dissolved oxygen (DO) limitation and FA inhibition was substantially denser and probably had a lower detachment rate. © 2014 Wiley Periodicals, Inc.

  4. Health Hazard Evaluation Report HETA 84-412-1612, Drs. Youdelman and Teig, Brentwood, New York. [Nitrous oxide

    Energy Technology Data Exchange (ETDEWEB)

    Crandall, M.S.

    1985-07-01

    Environmental and breathing zone samples were analyzed for nitrous-oxide (10102440) at two oral surgery clinics in Holbrook and Brentwood, New York on July 30 to 31, 1984. The evaluation was requested by the dentists because of general concern regarding the extent of exposure to nitrous oxide. The Brentwood office was equipped with a waste anesthetic gas scavenging system. Recommendations include checking the nitrous-oxide delivery and mixing systems at both clinics, installing a waste anesthetic gas scavenging system with a dedicated exhaust at the Holbrook office, and improving work practices at the Brentwood clinic.

  5. Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

    Science.gov (United States)

    J.S. Norman; J.E. Barrett

    2014-01-01

    Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

  6. Production of nitrous oxide in the auroral D and E regions

    Science.gov (United States)

    Zipf, E. C.; Prasad, S. S.

    1980-01-01

    A study of nitrous oxide formation mechanisms indicates that N2O concentrations greater than 10 to the 9th per cu cm could be produced in IBC III aurora or by lower-level activity lasting for many hours, and, in favorable conditions, the N2O concentration could exceed the local nitric oxide density. An upper limit on the globally averaged N2O production rate from auroral activity is estimated at 2 x 10 to the 27th per second.

  7. Nitrous oxide metabolism in nitrate-reducing bacteria: Physiology and regulatory mechanisms

    OpenAIRE

    Torres, Maria; Simon, Jorg; Rowley, Gary; Bedmar, Eulogio; Richardson, David; Gates, Andrew; Delgado, Maria

    2016-01-01

    Nitrous oxide (N2O) is an important greenhouse gas (GHG) with substantial global warming potential and also contributes to ozone depletion through photochemical nit- ric oxide (NO) production in the stratosphere. The negative effects of N2O on climate and stratospheric ozone make N2O mitigation an international challenge. More than 60% of global N2O emissions are emitted from agricultural soils mainly due to the appli- cation of synthetic nitrogen-containing fertilizers. Thus, mitigation stra...

  8. Interaction of ammonia with semiconducting oxide surfaces

    Science.gov (United States)

    Nigam, Sandeep; Sahoo, Suman Kalyan; Majumder, Chiranjib

    2018-04-01

    Using density functional theory (DFT) we have investigated the adsorption of NH3 molecule on the rutile SnO2(110) and mixed Sn0.5Ti0.5O2(110) surfaces. NH3 molecule gets absorbed on the 5-coordinated Sn atom (Sn5c) of the surface in tilted mode having an additional hydrogen bond with nearby surface bridged oxygen (Obr) atom. After adsorption, 3a1 molecular orbital of ammonia undergo significant dispersal as it donates its electron to surface atoms. The adsorption energy is found to be 1.4-1.6eV. Inclusion of Ti atoms in the SnO2 lattice leads to decrease in the adsorption energy value.

  9. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

    Science.gov (United States)

    Anderson, I. C.; Levine, J. S.

    1986-01-01

    An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

  10. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions, and novel technologies

    Science.gov (United States)

    Schreiber, Frank; Wunderlin, Pascal; Udert, Kai M.; Wells, George F.

    2012-01-01

    Nitrous oxide (N2O) is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO) production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH) or the reduction of nitrite (NO−2) to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO−2 to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria (AOB). In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO−2, NH2OH, and nitroxyl (HNO). Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser absorption spectroscopy (QCLAS). In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build

  11. Nitric oxide and nitrous oxide turnover in natural and engineered microbial communities: biological pathways, chemical reactions and novel technologies

    Directory of Open Access Journals (Sweden)

    Frank eSchreiber

    2012-10-01

    Full Text Available Nitrous oxide (N2O is an environmentally important atmospheric trace gas because it is an effective greenhouse gas and it leads to ozone depletion through photo-chemical nitric oxide (NO production in the stratosphere. Mitigating its steady increase in atmospheric concentration requires an understanding of the mechanisms that lead to its formation in natural and engineered microbial communities. N2O is formed biologically from the oxidation of hydroxylamine (NH2OH or the reduction of nitrite (NO2- to NO and further to N2O. Our review of the biological pathways for N2O production shows that apparently all organisms and pathways known to be involved in the catabolic branch of microbial N-cycle have the potential to catalyze the reduction of NO2- to NO and the further reduction of NO to N2O, while N2O formation from NH2OH is only performed by ammonia oxidizing bacteria. In addition to biological pathways, we review important chemical reactions that can lead to NO and N2O formation due to the reactivity of NO2-, NH2OH and nitroxyl (HNO. Moreover, biological N2O formation is highly dynamic in response to N-imbalance imposed on a system. Thus, understanding NO formation and capturing the dynamics of NO and N2O build-up are key to understand mechanisms of N2O release. Here, we discuss novel technologies that allow experiments on NO and N2O formation at high temporal resolution, namely NO and N2O microelectrodes and the dynamic analysis of the isotopic signature of N2O with quantum cascade laser based absorption spectroscopy. In addition, we introduce other techniques that use the isotopic composition of N2O to distinguish production pathways and findings that were made with emerging molecular techniques in complex environments. Finally, we discuss how a combination of the presented tools might help to address important open questions on pathways and controls of nitrogen flow through complex microbial communities that eventually lead to N2O build-up.

  12. Nitrous Oxide (N2O) Emissions by Termites: Does the Feeding Guild Matter?

    Science.gov (United States)

    Brauman, Alain; Majeed, Muhammad Zeeshan; Buatois, Bruno; Robert, Alain; Pablo, Anne-Laure; Miambi, Edouard

    2015-01-01

    In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O). Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1) (g dry wt.)(-1) for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1) (g dry wt.)(-1) for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1) (g dry wt.)(-1). Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA) and denitrifying (nirK, nirS, nosZ) gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

  13. Nitrous Oxide (N2O Emissions by Termites: Does the Feeding Guild Matter?

    Directory of Open Access Journals (Sweden)

    Alain Brauman

    Full Text Available In the tropics, termites are major players in the mineralization of organic matter leading to the production of greenhouse gases including nitrous oxide (N2O. Termites have a wide trophic diversity and their N-metabolism depends on the feeding guild. This study assessed the extent to which N2O emission levels were determined by termite feeding guild and tested the hypothesis that termite species feeding on a diet rich in N emit higher levels of N2O than those feeding on a diet low in N. An in-vitro incubation approach was used to determine the levels of N2O production in 14 termite species belonging to different feeding guilds, collected from a wide range of biomes. Fungus-growing and soil-feeding termites emit N2O. The N2O production levels varied considerably, ranging from 13.14 to 117.62 ng N2O-N d(-1 (g dry wt.(-1 for soil-feeding species, with Cubitermes spp. having the highest production levels, and from 39.61 to 65.61 ng N2O-N d(-1 (g dry wt.(-1 for fungus-growing species. Wood-feeding termites were net N2O consumers rather than N2O producers with a consumption ranging from 16.09 to 45.22 ng N2O-N d(-1 (g dry wt.(-1. Incubating live termites together with their mound increased the levels of N2O production by between 6 and 13 fold for soil-feeders, with the highest increase in Capritermes capricornis, and between 14 and 34 fold for fungus-growers, with the highest increase in Macrotermes muelleri. Ammonia-oxidizing (amoA-AOB and amoA-AOA and denitrifying (nirK, nirS, nosZ gene markers were detected in the guts of all termite species studied. No correlation was found between the abundance of these marker genes and the levels of N2O production from different feeding guilds. Overall, these results support the hypothesis that N2O production rates were higher in termites feeding on substrates with higher N content, such as soil and fungi, compared to those feeding on N-poor wood.

  14. Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene.

    Science.gov (United States)

    Kaspar, H F; Tiedje, J M

    1981-03-01

    15N tracer methods and gas chromatography coupled to an electron capture detector were used to investigate dissimilatory reduction of nitrate and nitrite by the rumen microbiota of a fistulated cow. Ammonium was the only 15N-labeled end product of quantitative significance. Only traces of nitrous oxide were detected as a product of nitrate reduction; but in experiments with nitrite, up to 0.3% of the added nitrogen accumulated as nitrous oxide, but it was not further reduced. Furthermore, when 13NO3- was incubated with rumen microbiota virtually no [13N]N2 was produced. Acetylene partially inhibited the reduction of nitrite to ammonium as well as the formation of nitrous oxide. It is suggested that in the rumen ecosystem nitrous oxide is a byproduct of dissimilatory nitrite reduction to ammonium rather than a product of denitrification and that the latter process is absent from the rumen habitat.

  15. GOZCARDS Source Data for Nitrous Oxide Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Source Data for Nitrous Oxide Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozSmlpN2O) contains zonal means and related...

  16. GOZCARDS Merged Data for Nitrous Oxide Monthly Zonal Means on a Geodetic Latitude and Pressure Grid V1.01

    Data.gov (United States)

    National Aeronautics and Space Administration — The GOZCARDS Merged Data for Nitrous Oxide Monthly Zonal Averages on a Geodetic Latitude and Pressure Grid product (GozMmlpN2O) contains zonal means and related...

  17. Nitrogen and Oxygen Isotope Effects of Ammonia Oxidation by Thermophilic Thaumarchaeota from a Geothermal Water Stream.

    Science.gov (United States)

    Nishizawa, Manabu; Sakai, Sanae; Konno, Uta; Nakahara, Nozomi; Takaki, Yoshihiro; Saito, Yumi; Imachi, Hiroyuki; Tasumi, Eiji; Makabe, Akiko; Koba, Keisuke; Takai, Ken

    2016-08-01

    Ammonia oxidation regulates the balance of reduced and oxidized nitrogen pools in nature. Although ammonia-oxidizing archaea have been recently recognized to often outnumber ammonia-oxidizing bacteria in various environments, the contribution of ammonia-oxidizing archaea is still uncertain due to difficulties in the in situ quantification of ammonia oxidation activity. Nitrogen and oxygen isotope ratios of nitrite (δ(15)NNO2- and δ(18)ONO2-, respectively) are geochemical tracers for evaluating the sources and the in situ rate of nitrite turnover determined from the activities of nitrification and denitrification; however, the isotope ratios of nitrite from archaeal ammonia oxidation have been characterized only for a few marine species. We first report the isotope effects of ammonia oxidation at 70°C by thermophilic Thaumarchaeota populations composed almost entirely of "Candidatus Nitrosocaldus." The nitrogen isotope effect of ammonia oxidation varied with ambient pH (25‰ to 32‰) and strongly suggests the oxidation of ammonia, not ammonium. The δ(18)O value of nitrite produced from ammonia oxidation varied with the δ(18)O value of water in the medium but was lower than the isotopic equilibrium value in water. Because experiments have shown that the half-life of abiotic oxygen isotope exchange between nitrite and water is longer than 33 h at 70°C and pH ≥6.6, the rate of ammonia oxidation by thermophilic Thaumarchaeota could be estimated using δ(18)ONO2- in geothermal environments, where the biological nitrite turnover is likely faster than 33 h. This study extended the range of application of nitrite isotopes as a geochemical clock of the ammonia oxidation activity to high-temperature environments. Because ammonia oxidation is generally the rate-limiting step in nitrification that regulates the balance of reduced and oxidized nitrogen pools in nature, it is important to understand the biological and environmental factors underlying the regulation of

  18. Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene.

    OpenAIRE

    Kaspar, H F; Tiedje, J M

    1981-01-01

    15N tracer methods and gas chromatography coupled to an electron capture detector were used to investigate dissimilatory reduction of nitrate and nitrite by the rumen microbiota of a fistulated cow. Ammonium was the only 15N-labeled end product of quantitative significance. Only traces of nitrous oxide were detected as a product of nitrate reduction; but in experiments with nitrite, up to 0.3% of the added nitrogen accumulated as nitrous oxide, but it was not further reduced. Furthermore, whe...

  19. Treatment performance, nitrous oxide production and microbial community under low-ammonium wastewater in a CANON process.

    Science.gov (United States)

    Mi, Weixing; Zhao, Jianqiang; Ding, Xiaoqian; Ge, Guanghuan; Zhao, Rixiang

    2017-12-01

    To investigate the characteristics of anaerobic ammonia oxidation for treating low-ammonium wastewater, a continuous-flow completely autotrophic nitrogen removal over nitrite (CANON) biofilm reactor was studied. At a temperature of 32 ± 1 °C and a pH between 7.5 and 8.2, two operational experiments were performed: the first one fixed the hydraulic retention time (HRT) at 10 h and gradually reduced the influent ammonium concentrations from 210 to 50 mg L -1 ; the second one fixed the influent ammonium concentration at 30 mg L -1 and gradually decreased the HRT from 10 to 3 h. The results revealed that the total nitrogen removal efficiency exceeded 80%, with a corresponding total nitrogen removal rate of 0.26 ± 0.01 kg N m -3 d -1 at the final low ammonium concentration of 30 mg L -1 . Small amounts of nitrous oxide (N 2 O) up to 0.015 ± 0.004 kg m -3 d -1 at the ammonium concentration of 210 mg L -1 were produced in the CANON process and decreased with the decrease in the influent ammonium loads. High-throughput pyrosequencing analysis indicated that the dominant functional bacteria 'Candidatus Kuenenia' under high influent ammonium levels were gradually succeeded by Armatimonadetes_gp5 under low influent ammonium levels.

  20. Relationships between Fungal Biomass and Nitrous Oxide Emission in Upland Rice Soils under No Tillage and Cover Cropping Systems.

    Science.gov (United States)

    Zhaorigetu; Komatsuzaki, Masakazu; Sato, Yoshinori; Ohta, Hiroyuki

    2008-01-01

    The relationships between soil microbial properties and nitrous oxide emission were examined in upland soil under different tillage systems [no tillage (NT), rotary and plow tillage] and cover crop systems (fallow, cereal rye, and hairy vetch) in 2004 and 2005. Microbiological analyses included the determination of soil ergosterol as an indicator of fungal biomass, bacterial plate counting, and MPN estimations of ammonia oxidizers and denitrifiers. The combined practice of NT with rye-cover crop treatment increased fungal biomass but not bacterial populations in 0-10 cm deep soils. Such increase in fungal biomass was not found in 10-20 cm and 20-30 cm deep cover-cropped NT soil. The combined practice of NT with rye-cover cropping resulted in higher in situ N(2)O emission rates compared with rotary- and plow-till treatments. N(2)O flux was positively correlated with soil ergosterol content but not with denitrifier MPN and other soil chemical properties. These results suggested a significant contribution of fungi to N(2)O emission in cover-cropped NT soils.

  1. Using Pure Cultures to Define the Site Preference of Nitrous Oxide Produced by Microbial Nitrification and Denitrification

    Science.gov (United States)

    Sutka, R. L.; Breznak, J. A.; Ostrom, N. E.; Ostrom, P. H.; Gandhi, H.

    2004-12-01

    Defining the site preference of nitrous oxide (N2O) produced in pure culture studies is crucial to interpreting field data. We have previously demonstrated that the intramolecular distribution of nitrogen isotopes (isotopomers) can be used to differentiate N2O produced by nitrifier denitrification and nitrification in cultures of Nitrosomonas europaea. Here, we have expanded on our initial results and evaluated the isotopomeric composition of N2O produced during nitrification and nitrifier denitrification with cultures of Nitrosospira multiformis. In addition, we have analyzed N2O produced during methanotrophic nitrification, denitrification, and fungal denitrification. To evaluate N2O production during nitrification and nitrifier denitrification, we compared the site preference of N2O formed as a result of nitrite reduction and hydroxylamine oxidation with Nitrosomonas europaea and Nitrosospira multiformis. The average site preference of N2O produced by hydroxylamine oxidation was similar for Nitrosomonas europaea (33.0 ± 3.5 ‰ ) and Nitrosospira multiformis (33.1 ± 4.2 ‰ ). Nitrous oxide produced by nitrifier-denitrification by Nitrosomonas europaea and Nitrosospira multiformis had a similar site preference of - 1.4 ± 4.4 ‰ and - 1.1 ± 2.6 ‰ respectively. The results indicate that it is possible to differentiate between N2O produced by nitrite reduction and hydroxylamine oxidation by ammonia oxidizing bacteria. Methanotrophic nitrification was evaluated by analyzing the N2O produced during hydroxylamine oxidation in concentrated cell suspensions of two methane oxidizing bacteria. The site preference of N2O produced by the two methane oxidizers, Methylococcus capsulatus Bath and Methylosinus trichosporium was 31.8 ± 4.7 ‰ and 33.0 ± 4.5 ‰ respectively. The results indicate that a site preference of 33 ‰ is applicable for nitrification regardless of whether a methane oxidizer or ammonia oxidizer is involved in the reaction. To determine the site

  2. Simulation of nitrous oxide and nitric oxide emissions from tropical primary forests in the Costa Rican Atlantic Zone

    Science.gov (United States)

    Shuguanga Liu; William A. Reiners; Michael Keller; Davis S. Schimel

    2000-01-01

    Nitrous oxide (N2O) and nitric oxide (NO) are important atmospheric trace gases participating in the regulation of global climate and environment. Predictive models on the emissions of N2O and NO emissions from soil into the atmosphere are required. We modified the CENTURY model (Soil Sci. Soc. Am. J., 51 (1987) 1173) to simulate the emissions of N2O and NO from...

  3. Determination of emissions of methane and nitrous oxide in rice plantations in Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    Jorge Herrera

    2013-12-01

    Full Text Available Methane and nitrous oxide emissions fluxes were measured in 10 rice plantations located in Liberia, Guanacaste, working at least with 04 varieties of rice and two types of soil in the period August 2012 - April 2013. For the determination of flows static camera technique were used taking four air gas samples located in the headspace of the chamber using a plastic syringe of 12 ml at 0, 10, 20 and 30 min after camera location. The gas samples were analyzed with a gas chromatograph, equipped with FID and ECD. Averages of flow methane and nitrous oxide were recorded between 0,12 to 1,9 kg ha-1d-1 and 0,11 - 1,1 mg ha-1d-1, respectively, and no significant difference was found (p < 0,05 in the values between different rice varieties and soil types subject experimental design.

  4. Protonated Nitrous Oxide, NNOH(+): Fundamental Vibrational Frequencies and Spectroscopic Constants from Quartic Force Fields

    Science.gov (United States)

    Huang, Xinchuan; Fortenberry, Ryan C.; Lee, Timothy J.

    2013-01-01

    The interstellar presence of protonated nitrous oxide has been suspected for some time. Using established high-accuracy quantum chemical techniques, spectroscopic constants and fundamental vibrational frequencies are provided for the lower energy O-protonated isomer of this cation and its deuterated isotopologue. The vibrationally-averaged B0 and C0 rotational constants are within 6 MHz of their experimental values and the D(subJ) quartic distortion constants agree with experiment to within 3%. The known gas phase O-H stretch of NNOH(+) is 3330.91 cm(exp-1), and the vibrational configuration interaction computed result is 3330.9 cm(exp-1). Other spectroscopic constants are also provided, as are the rest of the fundamental vibrational frequencies for NNOH(+) and its deuterated isotopologue. This high-accuracy data should serve to better inform future observational or experimental studies of the rovibrational bands of protonated nitrous oxide in the ISM and the laboratory.

  5. Treatment-Resistant Major Depression: Rationale for NMDA Receptors as Targets and Nitrous Oxide as Therapy

    Science.gov (United States)

    Zorumski, Charles F.; Nagele, Peter; Mennerick, Steven; Conway, Charles R.

    2015-01-01

    Major depressive disorder (MDD) remains a huge personal and societal encumbrance. Particularly burdensome is a virulent subtype of MDD, treatment resistant major depression (TMRD), which afflicts 15–30% of MDD patients. There has been recent interest in N-methyl-d-aspartate receptors (NMDARs) as targets for treatment of MDD and perhaps TMRD. To date, most pre-clinical and clinical studies have focused on ketamine, although psychotomimetic and other side effects may limit ketamine’s utility. These considerations prompted a recent promising pilot clinical trial of nitrous oxide, an NMDAR antagonist that acts through a mechanism distinct from that of ketamine, in patients with severe TRMD. In this paper, we review the clinical picture of TRMD as a subtype of MDD, the evolution of ketamine as a fast-acting antidepressant, and clinical and basic science studies supporting the possible use of nitrous oxide as a rapid antidepressant. PMID:26696909

  6. Aeration Strategies To Mitigate Nitrous Oxide Emissions from Single-Stage Nitritation/Anammox Reactors

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Mutlu, A. Gizem; Jensen, Marlene Mark

    2014-01-01

    Autotrophic nitrogen removal is regarded as a resource efficient process to manage nitrogen-rich residual streams. However, nitrous oxide emissions of these processes are poorly documented and strategies to mitigate emissions unknown. In this study, two sequencing batch reactors performing single...... was noted when the duration of aeration was increased while decreasing air flow rate (10.9 +/- 3.2% Delta N2O/Delta TN). The extant ammonium oxidation activity (mgNH(4)(+)-N/gVSS.min) positively correlated with the specific N2O production rate (mgN(2)O-N/gVSS.min) of the systems. Operating under conditions......-stage nitritation/anammox were operated under different aeration strategies, gradually adjusted over six months. At constant but limiting oxygen loading, synthetic reject water was fed (0.75g-N/L.d) and high nitrogen removal efficiencies (83 +/- 5 and 88 +/- 2%) obtained. Dynamics of liquid phase nitrous (N2O...

  7. Myeloneuropathy following nitrous oxide anesthaesia in a patient with macrocytic anaemia

    Energy Technology Data Exchange (ETDEWEB)

    Sesso, R.M.C.C.; Iunes, Y.; Melo, A.C.P. [Department of Neurology, Instituto de Assistencia Medica ao Servidor Publico Estadual, Sao Paulo (Brazil)

    1999-08-01

    The neurological condition triggered by anaesthesia with nitrous oxide involves the cyanocobalamine pathway and is characterised by progressive demyelination and axonal lesions of the peripheral nerves and cervicothoracic spinal cord (posterior and anterolateral columns) giving a peripheral neuropathy and very frequently subacute combined degeneration of the spinal cord. It is possible to show these demyelinating lesions by MRI of the spine, allowing early diagnosis and follow-up. We describe a case of myeloneuropathy with onset a few hours after nitrous oxide anaesthesia in a patient with macrocytic anaemia and possible subclinical vitamin B{sub 12} deficiency and MRI evidence of a lesion of the cervical spinal cord. Neurological and haematological improvement followed cyanocobalamine replacement. (orig.) With 2 figs., 15 refs.

  8. Spatial oxygen distribution and nitrous oxide emissions from soil after manure application

    DEFF Research Database (Denmark)

    Zhu, Kun; Bruun, Sander; Larsen, Morten

    2014-01-01

    The availability and spatial distribution of oxygen (O2) in agricultural soil are controlling factors in the production and emission of nitrous oxide (N2O) to the atmosphere, but most experiments investigating the effects of various factors on N2O emissions in soil have been conducted without...... to interpret data on N2O emissions following a uniform or layered amendment of manure to agricultural soil. The spatial distribution of O2 and gas emission rates were monitored for 12 h. An anoxic layer formed rapidly around the layered manure, whereas the uniformly distributed manure led to a more widespread...... anoxia. Nitrous oxide emissions increased immediately after depletion of O2 in the manure-amended treatments. Greater understanding and improved knowledge of the spatial distribution of O2 is clearly beneficial and can be used to devise improved application strategies for mitigating N2O emissions from...

  9. Diversity of Ammonia Oxidizing Archaea in Tropical Compost Systems

    OpenAIRE

    Vidya eDe Gannes; Gaius eEudoxie; David H Dyer; William James Hickey

    2012-01-01

    Composting is widely used to transform waste materials into valuable agricultural products. In the tropics, large quantities of agricultural wastes could be potentially useful in agriculture after composting. However, while microbiological processes of composts in general are well established, relatively little is known about microbial communities that may be unique to these in tropical systems, particularly nitrifiers. The recent discovery of ammonia oxidizing archaea (AOA) has changed the p...

  10. Nitrous oxide emissions from cattle-impacted pasture soil amended with nitrate and glucose

    Czech Academy of Sciences Publication Activity Database

    Hynšt, Jaroslav; Brůček, Petr; Šimek, Miloslav

    2007-01-01

    Roč. 43, č. 6 (2007), s. 853-859 ISSN 0178-2762 R&D Projects: GA ČR GA526/04/0325; GA AV ČR IAA600660605 Grant - others:MŠMT(CZ) 21-1072/2004 Institutional research plan: CEZ:AV0Z60660521 Source of funding: V - iné verejné zdroje Keywords : nitrous oxide * nitrate * emissions Subject RIV: EH - Ecology, Behaviour Impact factor: 1.191, year: 2007

  11. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    International Nuclear Information System (INIS)

    Yoosefian, Mehdi

    2017-01-01

    Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N_2O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N_2O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N_2O onto CNT, the horizontal adsorption with E_a_d_s = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N_2O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N_2O were investigated. Adsorption of N_2O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N_2O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N_2O sensors.

  12. Effects of excretal returns and soil compaction on nitrous oxide emissions from a cattle overwintering area

    Czech Academy of Sciences Publication Activity Database

    Šimek, Miloslav; Brůček, Petr; Hynšt, Jaroslav; Uhlířová, Eva; Petersen, S. O.

    2006-01-01

    Roč. 112, 2-3 (2006), s. 186-191 ISSN 0167-8809 R&D Projects: GA AV ČR(CZ) KSK3046108; GA ČR(CZ) GA526/04/0325 Grant - others:Evropská unie(XE) EVK2-CT-2000-00096 Institutional research plan: CEZ:AV0Z6066911 Keywords : cattle overwintering * emissions * nitrous oxide Subject RIV: EH - Ecology, Behaviour Impact factor: 1.832, year: 2006

  13. Nitrous oxide emission by the non-denitrifying, nitrate ammonifier Bacillus licheniformis

    OpenAIRE

    Sun, Yihua; De Vos, Paul; Heylen, Kim

    2016-01-01

    Background Firmicutes have the capacity to remove excess nitrate from the environment via either denitrification, dissimilatory nitrate reduction to ammonium or both. The recent renewed interest in their nitrogen metabolism has revealed many interesting features, the most striking being their wide variety of dissimilatory nitrate reduction pathways. In the present study, nitrous oxide production from Bacillus licheniformis, a ubiquitous Gram-positive, spore-forming species with many industria...

  14. Cryptogamic stem covers may contribute to nitrous oxide consumption by mature beech trees

    Czech Academy of Sciences Publication Activity Database

    Macháčová, Kateřina; Maier, M.; Svobodová, Kateřina; Lang, F.; Urban, Otmar

    2017-01-01

    Roč. 7, OCT (2017), č. článku 13243. ISSN 2045-2322 R&D Projects: GA MŠk(CZ) LO1415; GA MŠk(CZ) LM2015061; GA ČR(CZ) GJ17-18112Y Institutional support: RVO:67179843 Keywords : nitrous oxide * N2O * field conditions * cryptogamic stem Subject RIV: ED - Physiology OBOR OECD: Plant sciences, botany Impact factor: 4.259, year: 2016

  15. Evaluation of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents

    Directory of Open Access Journals (Sweden)

    Priya Subramaniam

    2017-01-01

    Full Text Available Background: Conscious sedation is used in the pediatric dentistry to reduce fear and anxiety in children and promote favorable treatment outcomes. To achieve them, the primary clinical need is for a well-tolerated, effective, and expedient analgesic and sedative agent that is safe to use. Aim: The aim of the present study was to evaluate the efficacy of nitrous oxide-oxygen and triclofos sodium as conscious sedative agents in 5–10-year-old children. Methodology: Sixty children aged 5–10 years showing anxious, uncooperative, and apprehensive behavior were randomly divided and assigned into two groups (Groups A and B such that Group A received 40% nitrous oxide-60% oxygen and Group B received triclofos sodium in the dose of 70 mg/kg body weight, given 30 min before the treatment procedure. During the whole course of sedation procedure, the response of the child was assessed using Houpt's behavior rating scale. The acceptance of route of drug administration by the patient and parent was also assessed. Data obtained were statistically evaluated using the Mann–Whitney U-test and Chi-square test. Results: Children sedated with triclofos sodium were significantly more drowsy and disoriented compared to those sedated with nitrous oxide. The overall behavior of children in both the groups was similar. Good parental acceptance was observed for both the routes of administration. Patients accepted the oral route significantly better than inhalation route. Conclusion: Both nitrous oxide-oxygen and triclofos sodium were observed to be effective sedative agents, for successful and safe use in 5–10-year-old dental patients. Patients showed a good acceptance of the oral route compared to the inhalation route for sedation.

  16. Low nitrous oxide production in intermittent-feed high performance nitritating reactors

    DEFF Research Database (Denmark)

    Su, Qingxian; Jensen, Malene M.; Smets, Barth F.

    Nitrous oxide (N2O) production from autotrophic nitrogen removal processes, especially nitritating systems, is of growing concern. N2O dynamics were characterized and N2O production factors were quantified in two lab-scale intermittent-feed nitritating SBRs. 93 ± 14% of the oxidized ammonium...... was converted to nitrite, with the average total net N2O production of 2.1 ± 0.7% of the ammonium oxidized. Operation with intermittent feeding appears an effective optimization approach to mitigate N2O emissions from nitritating systems. Net N2O production rates transiently increased with a rise in pH after...

  17. Effect of substrate availability on nitrous oxide production by deammonification processes under anoxic conditions.

    Science.gov (United States)

    Schneider, Yvonne; Beier, Maike; Rosenwinkel, Karl-Heinz

    2012-05-01

    Due to its high global warming potential, nitrous oxide (N(2)O) emissions from wastewater treatment processes have recently received a high degree of attention. Nevertheless, there is still a lack of information regarding the microbiological processes leading to N(2)O production. In this study, two lab-scale sequencing batch reactors were operated with deammonification biomass to investigate the role of denitrification and the influence of substrate availability regarding N(2)O formation during the anoxic phase of deammonification. Three different operational phases were established: within the first phase conversion by anammox was favoured and after a transition phase, denitrification activity was promoted. Low nitrous oxide production was observed during stable operation aiming for anammox conversion. Pulsed inflow of the wastewater containing ammonium (NH(4)(+)) and nitrite (NO(2)(-)) led to increased N(2)O production rates. Within the period of denitrification as dominating nitrogen conversion process, the nitrous oxide concentration level was higher during continuous inflow conditions, but the reaction to pulsed inflow was less pronounced. The results indicated that denitrification was responsible for N(2)O formation from the deammonification biomass. Operational settings to achieve suppression of denitrification processes to a large extend were deducted from the results of the experiments. © 2012 The Authors. Microbial Biotechnology © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. Denitrification: an important pathway for nitrous oxide production in tropical mangrove sediments (Goa, India).

    Science.gov (United States)

    Fernandes, Sheryl Oliveira; Bharathi, P A Loka; Bonin, Patricia C; Michotey, Valérie D

    2010-01-01

    Net nitrous oxide production and denitrification activity were measured in two mangrove ecosystems of Goa, India. The relatively pristine site Tuvem was compared to Divar, which is prone to high nutrient input. Stratified sampling at 2-cm intervals within the 0- to 10-cm depth range showed that N2O production at both the locations decreased with depth. Elevated denitrification activity at Divar resulted in maximum production of up to 1.95 nmol N2O-N g(-1) h(-1) at 2 to 4 cm, which was three times higher than at Tuvem. Detailed investigations to understand the major pathway contributing to N2O production performed at Tuvem showed that incomplete denitrification was responsible for up to 43 to 93% of N2O production. Nitrous oxide production rates closely correlated to nitrite concentration (n = 15; r = -0.47; p production. Nitrous oxide production through nitrification was below detection, affirming that denitrification is the major pathway responsible for production of the greenhouse gas. Net N2O production in these mangrove systems are comparatively higher than those reported from other natural estuarine sediments and therefore warrant mitigation measures.

  19. Effects of some anaesthetics on honeybees: nitrous oxide, carbon dioxide, ammonium nitrate smoker fumes

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J

    1954-08-01

    Honeybees were apparently unaffected by atmospheric oxygen concentrations between 7% and 100%, and only became motionless when the oxygen concentration was less than 2%. The effects of nitrous oxide-oxygen mixtures differed little, if at all, from those nitrogen-oxygen mixtures. Bees were not visibly affected by carbon dioxide concentrations up to 10-15% but they became motionless if the concentration exceeded 40-45%. Fumes produced by adding ammonium nitrate to the fuel in a beekeeper's smoker were found to contain hydrogen cyanide or cyanogen. Their effectiveness as an anaesthetic may be due to this or to some unidentified component, but not to nitrous oxide. All three anaesthetics caused foraging bees to stop collecting pollen, and accelerated the retrogression of the pharyngeal glands of young bees. Anaesthesia of a few bees in a colony with nitrous oxide, carbon dioxide, or ammonium nitrate smoker fumes did not appear to inhibit their drift back to the original site when their hive was moved, nor was any reduction in drifting observed when a whole colony was moved while anaesthetized with ammonium nitrate smoker fumes. 4 tables.

  20. Nitrous oxide and nitrate concentration in under-drainage from arable fields subject to diffuse pollution mitigation measures

    Science.gov (United States)

    Hama-Aziz, Zanist; Hiscock, Kevin; Adams, Christopher; Reid, Brian

    2016-04-01

    Atmospheric nitrous oxide concentrations are increasing by 0.3% annually and a major source of this greenhouse gas is agriculture. Indirect emissions of nitrous oxide (e.g. from groundwater and surface water) account for about quarter of total nitrous oxide emissions. However, these indirect emissions are subject to uncertainty, mainly due to the range in reported emission factors. It's hypothesised in this study that cover cropping and implementing reduced (direct drill) cultivation in intensive arable systems will reduce dissolved nitrate concentration and subsequently indirect nitrous oxide emissions. To test the hypothesis, seven fields with a total area of 102 ha in the Wensum catchment in eastern England have been chosen for experimentation together with two fields (41 ha) under conventional cultivation (deep inversion ploughing) for comparison. Water samples from field under-drainage have been collected for nitrate and nitrous oxide measurement on a weekly basis from April 2013 for two years from both cultivation areas. A purge and trap preparation line connected to a Shimadzu GC-8A gas chromatograph fitted with an electron capture detector was used for dissolved nitrous oxide analysis. Results revealed that with an oilseed radish cover crop present, the mean concentration of nitrate, which is the predominant form of N, was significantly depleted from 13.9 mg N L-1 to 2.5 mg N L-1. However, slightly higher mean nitrous oxide concentrations under the cover crop of 2.61 μg N L-1 compared to bare fields of 2.23 μg N L-1 were observed. Different inversion intensity of soil tended to have no effect on nitrous oxide and nitrate concentrations. The predominant production mechanism for nitrous oxide was nitrification process and the significant reduction of nitrate was due to plant uptake rather than denitrification. It is concluded that although cover cropping might cause a slight increase of indirect nitrous oxide emission, it can be a highly effective

  1. Phenol by direct hydroxylation of benzene with nitrous oxide - role of surface oxygen species in the reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Reitzmann, A.; Klemm, E.; Emig, G. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Technische Chemie 1; Buchholz, S.A.; Zanthoff, H.W. [Bochum Univ. (Germany). Inst. of Technical Chemistry

    1998-12-31

    Transient experiments in a Temporal Analysis of Products (TAP) Reactor were performed to elucidate the role of surface oyxgen species in the oxidation of benzene to phenol on ZSM-5 type zeolites with nitrous oxide as a selective oxidant. It was shown by puls experiments with nitrous oxide that the mean lifetime of the generated surface oxygen species is between 0.2s at 500 C and about 4.2 s at 400 C. Afterwards the surface oxygen species desorb as molecular oxygen into the gas phase where total oxidation will take place if hydrocarbons are present. Dual puls experiments consisting of a nitrous oxide puls followed by a benzene puls allowed studying the reactivity of the surface oxygen species formed during the first puls. The observation of the phenol formation was impeded due to the strong sorption of phenol. Multipulse experiments were necessary to reach a pseudo steady state phenol yield. (orig.)

  2. Soil fluxes of methane, nitrous oxide, and nitric oxide from aggrading forests in coastal Oregon

    Science.gov (United States)

    Erickson, Heather E.; Perakis, Steven S.

    2014-01-01

    Soil exchanges of greenhouse and other gases are poorly known for Pacific Northwest forests where gradients in nutrient availability and soil moisture may contribute to large variations in fluxes. Here we report fluxes of methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) over multiple seasons from three naturally N-rich, aggrading forests of coastal Oregon, USA. Mean methane uptake rates (3.2 mg CH4 m−2 d−1) were high compared with forests globally, negatively related to water-filled pore space (WFPS), but unrelated to N availability or temperature. Emissions of NO (6.0 μg NO–N m−2 h−1) exceeded N2O (1.4 μg N2O–N m−2 h−1), except when WFPS surpassed 55%. Spatial variation in NO fluxes correlated positively with soil nitrate concentrations (which generally exceeded ammonium concentrations, indicating the overall high N status for the sites) and negatively with soil pH, and at one site increased with basal area of N2-fixing red alder. Combined NO and N2O emissions were greatest from the site with highest annual net N mineralization and lowest needle litterfall C/N. Our findings of high CH4 uptake and NO/N2O ratios generally >1 most likely reflect the high porosity of the andic soils underlying the widespread regenerating forests in this seasonally wet region.

  3. The effects of fire on biogenic soil emissions of nitric oxide and nitrous oxide

    Science.gov (United States)

    Levine, Joel S.; Cofer, Wesley R., III; Sebacher, Daniel I.; Boston, Penelope J.; Winstead, Edward L.; Sebacher, Shirley

    1988-01-01

    Measurements of biogenic soil emissions of nitric oxide (NO) and nitrous oxide (N2O) before and after a controlled burn conducted in a chaparral ecosystem on June 22, 1987, showed significantly enhanced emissions of both gases after the burn. Mean NO emissions from heavily burned and wetted (to simulate rainfall) sites exceeded 40 ng N/sq m s, and increase of 2 to 3 compared to preburn wetted site measurements. N2O emissions from burned and wetted sites ranged from 9 to 22 ng N/sq m s. Preburn N2O emissions from these wetted sites were all below the detection level of the instrumentation, indicating a flux below 2 ng N/sq m s. The flux of NO exceeded the N2O flux from burned wetted sites by factors ranging from 2.7 to 3.4. These measurements, coupled with preburn and postburn measurements of ammonium and nitrate in the soil of this chaparral ecosystem and measurements of NO and N2O emissions obtained under controlled laboratory conditions, suggest that the postfire enhancement of NO and N2O emissions is due to production of these gases by nitrifying bacteria.

  4. Si0.85Ge0.15 oxynitridation in nitric oxide/nitrous oxide ambient

    International Nuclear Information System (INIS)

    Dasgupta, Anindya; Takoudis, Christos G.; Lei Yuanyuan; Browning, Nigel D.

    2003-01-01

    Low temperature, nitric oxide (NO)/nitrous oxide (N 2 O) aided, sub-35 Aa Si 0.85 Ge 0.15 oxynitrides have been grown at 550 and 650 deg. C, while the oxynitridation feed gases have been preheated to 900 and 1000 deg. C, respectively, before entering the reaction zone. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy (SIMS) data suggest that NO-assisted oxynitridation incorporates more nitrogen than the N 2 O-assisted one, while there is minimal Ge segregation towards the dielectric/substrate interface in both oxynitridation processes. Moreover, SIMS results suggest that nitrogen is distributed throughout the film in contrast to high temperature Si oxynitridation, where nitrogen incorporation takes place near the dielectric/substrate interface. Z-contrast imaging with scanning transmission electron microscopy shows that the oxynitride grown in NO at 650 degree sign C has a sharp interface with the bulk Si 0.85 Ge 0.15 , while the roughness of the dielectric/Si 0.85 Ge 0.15 substrate interface is less than 2 Aa. These results are discussed in the context of an overall mechanism of SiGe oxynitridation

  5. Emissions of nitrous acid (HONO), nitric oxide (NO) and nitrous oxide (N2O) from boreal agricultural soil - Effect of N fertilization

    Science.gov (United States)

    Bhattarai, Hem Raj; Virkajärvi, Perttu; -Yli Pirilä, Pasi; Maljanen, Marja

    2017-04-01

    There is no doubt that nitrogen (N) fertilization has crucial role in increasing food production. However, in parallel it can cause severe impact in environment such as eutrophication, surface/groundwater pollution via nitrate (NO3-) leaching and emissions of N trace gases. Fertilization increases the emissions of nitrous oxide (N2O) which is 260 stronger greenhouse gas than carbon dioxide (CO2). It also enhances the emissions of nitric oxide (NO); an oxidized and very reactive form of nitrogen which can fluctuate the ozone (O3) concentration in atmosphere and cause acidification. The effects of N- fertilization on the emission of N2O and NO from agricultural soil are well known. However, the effects of N fertilization on nitrous acid (HONO) emissions are unknown. Few studies have shown that HONO is emitted from soil but they lack to interlink fertilization and HONO emission. HONO accounts for 17-34 % of hydroxyl (OH-) radical production? in the atmosphere, OH- radicals have vital role in atmospheric chemistry; they can cause photochemical smog, form O3, oxidize volatile organic compounds and also atmospheric methane (CH4). We formulated hypothesis that N fertilization will increase the HONO emissions as it does for N2O and NO. To study this, we took soil samples from agricultural soil receiving different amount of N-fertilizer (0, 250 and 450 kg ha-1) in eastern Finland. HONO emissions were measured by dynamic chamber technique connected with LOPAP (Quma Elektronik & Analytik GmbH), NO by NOx analyzer (Thermo scientific) and static chamber technique and gas chromatograph was used for N2O gas sampling and analysis. Several soil parameters were also measured to establish the relationship between the soil properties, fertilization rate and HONO emission. This study is important because eventually it will open up more questions regarding the forms of N loss from soils and impact of fertilization on atmospheric chemistry.

  6. Management matters: Testing a mitigation strategy of nitrous oxide emissions on managed grassland

    Science.gov (United States)

    Fuchs, Kathrin; Hörtnagl, Lukas; Eugster, Werner; Koller, Patrick; Käslin, Florian; Merbold, Lutz

    2017-04-01

    The magnitude of greenhouse gas (GHG) exchange between managed grasslands and the atmosphere depends besides climate predominantly on management practices. While natural or extensively managed grasslands are known to function as GHG sinks, intensively managed grasslands are characterized by substantial nitrous oxide (N2O) emissions diminishing their sink function. One potential N2O mitigation strategy is to reduce the required amount of nitrogen (N) fertilizer input by using biological nitrogen fixation (BNF) via legumes. However, the effect of legumes on nitrous oxide emissions is still not fully understood. In this study we quantify net GHG fluxes from two differently managed grassland parcels (mitigation, control) and relate our results to productivity (yields). In addition, we aim at revealing the influence of various driver variables on N2O exchange. Our experimental setup consisted of an eddy covariance tower that measured the net exchange of the three major anthropogenic GHGs, nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2). Both grassland parcels can be covered with this tower due to two prevailing wind directions. GHG flux measurements were accompanied by measurements of commonly known driver variables such as water filled pore space, soil temperature, soil oxygen concentrations and mineral N to disentangle the soil meteorological influence of N2O fluxes from human drivers. Following organic fertilizer application, we measured elevated N2O emissions (>1 nmol m-2 s-1) at the control parcel and unchanged N2O emissions at the treatment parcel. Net annual fluxes were 54% and 50% lower at the experimental parcel in 2015 and 2016, respectively. Annual yields did not significantly differ between parcels, but were slightly lower at the experimental parcel compared to the control parcel. Significantly lower nitrous oxide fluxes under experimental management indicate that nitrous oxide emissions can be effectively reduced at very low costs with a clover

  7. Environmental consequences from emission of nitrogen oxides and ammonia

    International Nuclear Information System (INIS)

    Iverfeldt, Aa.; Pleijel, H.; Klemedtsson, L.; Loevblad, G.; Omstedt, G.

    1995-02-01

    The aim of this study have been to compare environmental problems pertaining to nitrogen containing pollutants from power generation from biomass fuels. Local effects of NO x and NH 3 in air are normally small. Emission of NO x add plant toxic ozone, which is not the case at emission of NH 3 and N 2 O. The problem is slightly greater when siting in southern Sweden. The total emission of ammonium and nitrates are of major importance for acidification and nitrogen saturation. The largest contribution to the greenhouse effect comes from direct emission of nitrous oxide. The emission of N 2 O does not influence the siting aspects of the power plant, because of the global implications of this substance. 21 refs, 9 figs, 14 tabs

  8. Ammonia oxidation kinetics and temperature sensitivity of a natural marine community dominated by Archaea

    Science.gov (United States)

    Horak, Rachel E A; Qin, Wei; Schauer, Andy J; Armbrust, E Virginia; Ingalls, Anitra E; Moffett, James W; Stahl, David A; Devol, Allan H

    2013-01-01

    Archaeal ammonia oxidizers (AOAs) are increasingly recognized as prominent members of natural microbial assemblages. Evidence that links the presence of AOA with in situ ammonia oxidation activity is limited, and the abiotic factors that regulate the distribution of AOA natural assemblages are not well defined. We used quantitative PCR to enumerate amoA (encodes α-subunit of ammonia monooxygenase) abundances; AOA amoA gene copies greatly outnumbered ammonia-oxidizing bacteria and amoA transcripts were derived primarily from AOA throughout the water column of Hood Canal, Puget Sound, WA, USA. We generated a Michaelis–Menten kinetics curve for ammonia oxidation by the natural community and found that the measured Km of 98±14 nmol l−1 was close to that for cultivated AOA representative Nitrosopumilus maritimus SCM1. Temperature did not have a significant effect on ammonia oxidation rates for incubation temperatures ranging from 8 to 20 °C, which is within the temperature range for depths of measurable ammonia oxidation at the site. This study provides substantial evidence, through both amoA gene copies and transcript abundances and the kinetics response, that AOA are the dominant active ammonia oxidizers in this marine environment. We propose that future ammonia oxidation experiments use a Km for the natural community to better constrain ammonia oxidation rates determined with the commonly used 15NH4+ dilution technique. PMID:23657360

  9. Study on mechanism for oxidation of N,N-dimethylhydroxylamine by nitrous acid

    International Nuclear Information System (INIS)

    Li Gaoliang; He Hui

    2011-01-01

    The oxidation of N,N-dimethylhydroxylamine (DMHAN) by nitrous acid is investigated in perchloric acid and nitric acid medium, respectively. The effects of H + , DMHAN, ionic strength and temperature on the reaction are studied. The rate equation in perchloric acid medium has been determined to be -d[HNO 2 ]/dt = k[DMHAN][HNO 2 ], where k = 12.8 ± 1.0 (mol/L) -1 min -1 when the temperature is 18.5 deg C and the ionic strength is 0.73 mol/L with an activation energy about 41.5 kJ mol -1 . The reaction becomes complicated when it is performed in nitric acid medium. When the molarity of HNO 3 is higher than 1.0 mol/L, nitrous acid will be produced via the reaction between nitric acid and DMHAN. The reaction products are analyzed and the reaction mechanism is discussed in this paper. (author)

  10. Comparison of partial and full nitrification processes applied for treating high-strength nitrogen wastewaters: microbial ecology through nitrous oxide production.

    Science.gov (United States)

    Ahn, Joon Ho; Kwan, Tiffany; Chandran, Kartik

    2011-04-01

    The goal of this study was to compare the microbial ecology, gene expression, biokinetics, and N2O emissions from a lab-scale bioreactor operated sequentially in full-nitrification and partial-nitrification modes. Based on sequencing of 16S rRNA and ammonia monooxygenase subunit A (amoA) genes, ammonia oxidizing bacteria (AOB) populations during full- and partial-nitrification modes were distinct from one another. The concentrations of AOB (XAOB) and their respiration rates during full- and partial-nitrification modes were statistically similar, whereas the concentrations of nitrite oxidizing bacteria (XNOB) and their respiration rates declined significantly after the switch from full- to partial-nitrification. The transition from full-nitrification to partial nitrification resulted in a protracted transient spike of nitrous oxide (N2O) and nitric oxide (NO) emissions, which later stabilized. The trends in N2O and NO emissions correlated well with trends in the expression of nirK and norB genes that code for the production of these gases in AOB. Both the transient and stabilized N2O and NO emissions during partial nitrification were statistically higher than those during steady-state full-nitrification. Based on these results, partial nitrification strategies for biological nitrogen removal, although attractive for their reduced operating costs and energy demand, may need to be optimized against the higher carbon foot-print attributed to their N2O emissions.

  11. Cognitive properties of sedation agents: comparison of the effects of nitrous oxide and midazolam on memory and mood.

    Science.gov (United States)

    Thompson, J M; Neave, N; Moss, M C; Scholey, A B; Wesnes, K; Girdler, N M

    1999-11-27

    To compare the effects of nitrous oxide and midazolam on cognition and mood. A three-way, counterbalanced, cross-over study, using patients receiving conscious sedation for routine dental treatment. On each of three separate visits, patients performed a computerised test battery to determine baseline cognitive performance. Then, following administration of either midazolam, nitrous oxide, or no drug, patients re-performed the test battery. Finally, patients completed visual analogue scales assessing their subjective mood state. Relative to baseline performance, midazolam administration produced significantly slower reaction times compared with nitrous oxide and no-drug conditions. Furthermore, patients receiving midazolam were impaired in accuracy relative to the other conditions on many of the cognitive tasks, particularly those assessing the recall of information. Patient performance in nitrous oxide and control conditions did not significantly differ. These results could not be explained by differences in mood between the conditions, as subjective mood ratings during midazolam or nitrous oxide administration were very similar. It is important for clinicians to be aware that peri-operative recall of information is reduced in patients who have undergone midazolam sedation. This is an advantage for patients who are anxious, and do not wish to be aware of the operative treatment being performed. However, as the cognitive impairment is enduring, an adult escort and written post-operative instructions should be mandatory for midazolam sedation patients. In contrast, the use of nitrous oxide sedation does not significantly impair higher cognitive tasks and thus patients receiving nitrous oxide sedation can resume normal activities in the post-operative period.

  12. Effect of high-temperature treatment on Fe/ZSM-5 prepared by chemical vapor deposition of FeCl3. II. Nitrous oxide decomposition, selective oxidation of benzene to phenol, and selective reduction of nitric oxide by isobutane

    NARCIS (Netherlands)

    Zhu, Q.; Teeffelen, van R.M.; Santen, van R.A.; Hensen, E.J.M.

    2004-01-01

    The catalytic performance (nitrous oxide decomposition, hydroxylation of benzene to phenol with nitrous oxide, and selective reduction of nitric oxide by i-butane) was evaluated for a set of HZSM-5 and sublimed Fe/ZSM-5 catalysts, which have been extensively characterized in an earlier contribution

  13. Co-Mn-Al Mixed Oxides as Catalysts for Ammonia Oxidation to N2O.

    Czech Academy of Sciences Publication Activity Database

    Ludvíková, Jana; Jablońska, M.; Jirátová, Květa; Chmielarz, L.; Balabánová, Jana; Kovanda, F.; Obalová, L.

    2016-01-01

    Roč. 42, č. 3 (2016), s. 2669-2690 ISSN 0922-6168 R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : Co-Mn-Al mixed oxide s * catalytic ammonia oxidation * N2O production * mechanochemical production Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.369, year: 2016

  14. Intensive Ammonia and Methane Oxidation in Organic Liquid Manure Crusts

    DEFF Research Database (Denmark)

    Nielsen, Daniel Aagren; Nielsen, Lars Peter; Schramm, Andreas

    methane oxidizing bacteria (MOB) and are known to accumulate nitrite and nitrate, indicating the presence of ammonia oxidizers (AOB). We have surveyed six manure tanks with organic covers to investigate the prevalence of MOB and AOB and to link the potential activity with physical and chemical aspects...... characterized with respect to O2 availability by in situ profiling with electrochemical microsensors. Results show that oxygen penetration increased from few micrometers up to several centimetres with crust age. AOB and ammonium oxidation are ubiquitously present in well-developed manure crusts whereas MOB were...... also CH4 emission mitigation, an organic surface crust can be effective if populations of MOB and AOB are allowed to build up....

  15. Estimation of methane and nitrous oxide emission from paddy fields and uplands during 1990-2000 in Taiwan

    International Nuclear Information System (INIS)

    Shangshyng Yang; Chungming Liu; Yenlan Liu; Chaoming Lai

    2003-01-01

    To investigate the greenhouse gases emissions from paddy fields and uplands, methane and nitrous oxide emissions were estimated from local measurement and the IPCC guidelines during 1990-2000 in Taiwan. Annual methane emission from 182 807 to 242 298 ha of paddy field in the first crop season ranged from 8062 to 12 066 ton, and it was between 16 261 and 25 007 ton for 144 178-211 968 ha in the second crop season with local measurement. The value ranged from 12 132 to 17 465 ton, and from 16 046 to 24 762 ton of methane in the first and second crop season with the IPCC guidelines for multiple aeration treatments, respectively. Annual nitrous oxide emission was between 472 and 670 ton and between 236 and 359 ton in the first and second crop season, respectively. Methane and nitrous oxide emissions from uplands depend on crop, growth season, fertilizer application and environmental conditions. Annual methane emission from upland crops, vegetable, fruit, ornamental plants, forage crops and green manure crops was 138-252, 412-460, 97-100, 3-5, 4-5 and 3-51 ton, respectively. Annual nitrous oxide emission was 1080-1976, 1784-1994, 2540-2622, 31-54, 43-53 and 38-582 ton, respectively. Annual nitrous oxide emission ranged from 91 to 132 ton for 77 593-112 095 ton of nitrogen-fixing crops, from 991 to 1859 ton for 325 9731-6 183 441 ton of non-nitrogen-fixing crops, and from 1.77 to 2.22 Gg for 921 169-1 172 594 ton of chemical fertilizer application. In addition, rice hull burning emitted 19.3-24.2 ton of methane and 17.2-21.5 ton of nitrous oxide, and corn stalk burning emitted 2.1-4.2 ton of methane and 1.9-3.8 ton of nitrous oxide. Methane emission from the agriculture sector was 26 421-37 914 ton, and nitrous oxide emission was 9810-11 649 ton during 1990-2000 in Taiwan. Intermittent irrigation in paddy fields reduces significantly methane emission; appropriate application of nitrogen fertilization and irrigation in uplands and paddy fields also decreases nitrous oxide

  16. Different Recovery Processes of Soil Ammonia Oxidizers from Flooding Disturbance.

    Science.gov (United States)

    Ye, Fei; Ma, Mao-Hua; Op den Camp, Huub J M; Chatzinotas, Antonis; Li, Lei; Lv, Ming-Quan; Wu, Sheng-Jun; Wang, Yu

    2018-04-11

    Understanding how microorganisms respond to environmental disturbance is one of the key focuses in microbial ecology. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are responsible for ammonia oxidation which is a crucial step in the nitrogen cycle. Although the physiology, distribution, and activity of AOA and AOB in soil have been extensively investigated, their recovery from a natural disturbance remains largely unknown. To assess the recovery capacities, including resistance and resilience, of AOA and AOB, soil samples were taken from a reservoir riparian zone which experienced periodically water flooding. The samples were classified into three groups (flooding, recovery, and control) for a high-throughput sequencing and quantitative PCR analysis. We used a relative quantitative index of both the resistance (RS) and resilience (RL) to assess the variation of gene abundance, alpha-diversity, and community composition. The AOA generally demonstrated a better recovery capability after the flooding disturbance compared to AOB. In particular, AOA were more resilient after the flooding disturbance. Taxa within the AOA and AOB showed different RS and RL values, with the most abundant taxa showing in general the highest RS indices. Soil NH 4 + and Fe 2+ /Fe 3+ were the main variables controlling the key taxa of AOA and AOB and probably influenced the resistance and resilience properties of AOA and AOB communities. The distinct mechanisms of AOA and AOB in maintaining community stability against the flooding disturbance might be linked to the different life-history strategies: the AOA community was more likely to represent r-strategists in contrast to the AOB community following a K-life strategy. Our results indicated that the AOA may play a vital role in ammonia oxidation in a fluctuating habitat and contribute to the stability of riparian ecosystem.

  17. Diversity of Ammonia Oxidizing Archaea in Tropical Compost Systems

    Directory of Open Access Journals (Sweden)

    Vidya eDe Gannes

    2012-07-01

    Full Text Available Composting is widely used to transform waste materials into valuable agricultural products. In the tropics, large quantities of agricultural wastes could be potentially useful in agriculture after composting. However, while microbiological processes of composts in general are well established, relatively little is known about microbial communities that may be unique to these in tropical systems, particularly nitrifiers. The recent discovery of ammonia oxidizing archaea (AOA has changed the paradigm of nitrification being initiated solely by ammonia oxidizing bacteria. In the present study, AOA abundance and diversity was examined in composts produced from combinations of plant waste materials common in tropical agriculture (rice straw, sugar cane bagasse, coffee hulls, which were mixed with either cow- or sheep-manure. The objective was to determine how AOA abundance and diversity varied as a function of compost system and time, the latter being a contrast between the start of the compost process (mesophilic phase and the finished product (mature phase. The results showed that AOA were relatively abundant in composts of tropical agricultural wastes, and significantly more so than were the ammonia-oxidizing bacteria. Furthermore, while the AOA communities in the composts were predominatly group I.1b, the communities were diverse and exhibited structures that diverged between compost types and phases. These patterns could be taken as indicators of the ecophysiological diversity in the soil AOA (groub I.1b, in that significantly different AOA communties developed when exposed to varying physico-chemical environments. Nitrification patterns and levels differed in the composts which, for the mature material, could have signifcant effects on its performanc as a plant growth medium. Thus, it will also be important to determine the association of AOA (and diversity in their communities with nitrification in these systems.

  18. Measurements of nitrous oxide emissions from P.F. fired power stations

    Science.gov (United States)

    Sloan, S. A.; Laird, C. K.

    Nitrous oxide (N 2O) was measured in the flue gas from four wall-fired and three corner-fired 500 MW boilers, fitted with either conventional or low-NO x burners, at four C.E.G.B. power stations. Measurements were made both by on-line non-dispersive infra red (NDIR) monitors and by extractive sampling for later laboratory analysis by electron capture gas chromatography (ECD GC). It was found that the on-line and laboratory methods were in good agreement for samples analyzed within 1-3 h of sampling, but that the nitrous oxide concentration in the stored samples had a tendency to increase with time, which was dependent on the concentration of water in the sample. Experiments with synthetic mixtures showed that the increase in nitrous oxide concentration was consistent with the overall reaction2NO+SO 2→N 2O+SO 3 in which nitric oxide is reduced by sulphur dioxide. The highest average N 2O concentration measured by the on-line analyzer was 16 vpm, and for most of the boilers monitored the concentration was less than 10 vpm. There was no statistically significant difference between the measured N 2O emissions from normal boilers and those fitted with low-NO x burners. It is suggested that these values are close to the true levels of N 2O emissions from p.f. fired boilers and that recent reports of high levels (up to 200 vpm) are likely to be an artefact resulting from the observed generation of N 2O in stored samples. A consequence of these measurements of N 2O is that current estimates of the contribution of emissions from p.f. fired boilers to the global N 2O budget are likely to be too high.

  19. Nitrous Oxide Production at a Fully Covered Wastewater Treatment Plant: Results of a Long-Term Online Monitoring Campaign.

    Science.gov (United States)

    Kosonen, Heta; Heinonen, Mari; Mikola, Anna; Haimi, Henri; Mulas, Michela; Corona, Francesco; Vahala, Riku

    2016-06-07

    The nitrous oxide emissions of the Viikinmäki wastewater treatment plant were measured in a 12 month online monitoring campaign. The measurements, which were conducted with a continuous gas analyzer, covered all of the unit operations of the advanced wastewater-treatment process. The relation between the nitrous oxide emissions and certain process parameters, such as the wastewater temperature, influent biological oxygen demand, and ammonium nitrogen load, was investigated by applying online data obtained from the process-control system at 1 min intervals. Although seasonal variations in the measured nitrous oxide emissions were remarkable, the measurement data indicated no clear relationship between these emissions and seasonal changes in the wastewater temperature. The diurnal variations of the nitrous oxide emissions did, however, strongly correlate with the alternation of the influent biological oxygen demand and ammonium nitrogen load to the aerated zones of the activated sludge process. Overall, the annual nitrous oxide emissions of 168 g/PE/year and the emission factor of 1.9% of the influent nitrogen load are in the high range of values reported in the literature but in very good agreement with the results of other long-term online monitoring campaigns implemented at full-scale wastewater-treatment plants.

  20. Recent patterns of methane and nitrous oxide fluxes in the terrestrial biosphere: The bottom-up approach (Invited)

    Science.gov (United States)

    Tian, H.

    2013-12-01

    Accurately estimating methane and nitrous oxide emissions from terrestrial ecosystems is critical for resolving global budgets of these greenhouse gases (GHGs) and continuing to mitigate climate warming. In this study, we use a bottom-up approach to estimate annual budgets of both methane and nitrous oxide in global terrestrial ecosystem during 1981-2010 and analyze the underlying mechanisms responsible for spatial and temporal variations in these GHGs. Both methane and nitrous oxide emissions significantly increased from 1981 to 2010, primarily owing to increased air temperature, nitrogen fertilizer use, and land use change. Methane and nitrous oxide emissions increased the fastest in Asia due to the more prominent environmental changes compared to other continents. The cooling effects by carbon dioxide sink in the terrestrial biosphere might be completely offset by increasing methane and nitrous oxide emissions, resulting in a positive global warming potential. Asia and South America were the largest contributors to increasing global warming potential. This study suggested that current management practices might not be effective enough to reduce future global warming.

  1. Effect of nitrous oxide on the efficacy of the inferior alveolar nerve block in patients with symptomatic irreversible pulpitis.

    Science.gov (United States)

    Stanley, William; Drum, Melissa; Nusstein, John; Reader, Al; Beck, Mike

    2012-05-01

    The inferior alveolar nerve (IAN) block does not always result in successful pulpal anesthesia. Anesthetic success rates might be affected by increased anxiety. Nitrous oxide has been shown to have both anxiolytic and analgesic properties. Therefore, the purpose of this prospective, randomized, double-blind, placebo-controlled study was to determine the effect of nitrous oxide on the anesthetic success of the IAN block in patients experiencing symptomatic irreversible pulpitis. One hundred emergency patients diagnosed with symptomatic irreversible pulpitis of a mandibular posterior tooth were enrolled in this study. Each patient was randomly assigned to receive an inhalation regimen of nitrous oxide/oxygen mix or room air/oxygen mix (placebo) 5 minutes before the administration of the IAN block. Endodontic access was begun 15 minutes after completion of the IAN block, and all patients had profound lip numbness. Success was defined as no or mild pain (visual analog scale recordings) on access or instrumentation. The success rate for the IAN block was 50% for the nitrous oxide group and 28% for the placebo group. There was a statistically significant difference between the 2 groups (P = .024). For mandibular teeth diagnosed with symptomatic irreversible pulpitis, administration of 30%-50% nitrous oxide resulted in a statistically significant increase in the success of the IAN block compared with room air/oxygen. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Global Emissions of Nitrous Oxide: Key Source Sectors, their Future Activities and Technical Opportunities for Emission Reduction

    Science.gov (United States)

    Winiwarter, W.; Höglund-Isaksson, L.; Klimont, Z.; Schöpp, W.; Amann, M.

    2017-12-01

    Nitrous oxide originates primarily from natural biogeochemical processes, but its atmospheric concentrations have been strongly affected by human activities. According to IPCC, it is the third largest contributor to the anthropogenic greenhouse gas emissions (after carbon dioxide and methane). Deep decarbonization scenarios, which are able to constrain global temperature increase within 1.5°C, require strategies to cut methane and nitrous oxide emissions on top of phasing out carbon dioxide emissions. Employing the Greenhouse gas and Air pollution INteractions and Synergies (GAINS) model, we have estimated global emissions of nitrous oxide until 2050. Using explicitly defined emission reduction technologies we demonstrate that, by 2030, about 26% ± 9% of the emissions can be avoided assuming full implementation of currently existing reduction technologies. Nearly a quarter of this mitigation can be achieved at marginal costs lower than 10 Euro/t CO2-eq with the chemical industry sector offering important reductions. Overall, the largest emitter of nitrous oxide, agriculture, also provides the largest emission abatement potentials. Emission reduction may be achieved by precision farming methods (variable rate technology) as well as by agrochemistry (nitrification inhibitors). Regionally, the largest emission reductions are achievable where intensive agriculture and industry are prevalent (production and application of mineral fertilizers): Centrally Planned Asia including China, North and Latin America, and South Asia including India. Further deep cuts in nitrous oxide emissions will require extending reduction efforts beyond strictly technological solutions, i.e., considering behavioral changes, including widespread adoption of "healthy diets" minimizing excess protein consumption.

  3. Nitrous Acid as an Oxidant in Acidic Media

    Science.gov (United States)

    1979-09-25

    current work is the account of Ogsts and Sawski3 who studied the oxidation of benzyl ethers at 90C in acidic, aqueous dioxane. They found an increase in...and G. Tobin, Chem. Com., 180 (1978); (b) J. Hoggett , R. Moodie, and K. Schofield, Chem. Comm., 605 (1969). 15. (a) B. Challis and A. Lawson. J. Chem

  4. Ammonia oxidation pathways and nitrifier denitrification are significant sources of N2O and NO under low oxygen availability.

    Science.gov (United States)

    Zhu, Xia; Burger, Martin; Doane, Timothy A; Horwath, William R

    2013-04-16

    The continuous increase of nitrous oxide (N2O) abundance in the atmosphere is a global concern. Multiple pathways of N2O production occur in soil, but their significance and dependence on oxygen (O2) availability and nitrogen (N) fertilizer source are poorly understood. We examined N2O and nitric oxide (NO) production under 21%, 3%, 1%, 0.5%, and 0% (vol/vol) O2 concentrations following urea or ammonium sulfate [(NH4)2SO4] additions in loam, clay loam, and sandy loam soils that also contained ample nitrate. The contribution of the ammonia (NH3) oxidation pathways (nitrifier nitrification, nitrifier denitrification, and nitrification-coupled denitrification) and heterotrophic denitrification (HD) to N2O production was determined in 36-h incubations in microcosms by (15)N-(18)O isotope and NH3 oxidation inhibition (by 0.01% acetylene) methods. Nitrous oxide and NO production via NH3 oxidation pathways increased as O2 concentrations decreased from 21% to 0.5%. At low (0.5% and 3%) O2 concentrations, nitrifier denitrification contributed between 34% and 66%, and HD between 34% and 50% of total N2O production. Heterotrophic denitrification was responsible for all N2O production at 0% O2. Nitrifier denitrification was the main source of N2O production from ammonical fertilizer under low O2 concentrations with urea producing more N2O than (NH4)2SO4 additions. These findings challenge established thought attributing N2O emissions from soils with high water content to HD due to presumably low O2 availability. Our results imply that management practices that increase soil aeration, e.g., reducing compaction and enhancing soil structure, together with careful selection of fertilizer sources and/or nitrification inhibitors, could decrease N2O production in agricultural soils.

  5. Biochemical characterization of the purple form of Marinobacter hydrocarbonoclasticus nitrous oxide reductase

    Science.gov (United States)

    Dell'Acqua, Simone; Pauleta, Sofia R.; Moura, José J. G.; Moura, Isabel

    2012-01-01

    Nitrous oxide reductase (N2OR) catalyses the final step of the denitrification pathway—the reduction of nitrous oxide to nitrogen. The catalytic centre (CuZ) is a unique tetranuclear copper centre bridged by inorganic sulphur in a tetrahedron arrangement that can have different oxidation states. Previously, Marinobacter hydrocarbonoclasticus N2OR was isolated with the CuZ centre as CuZ*, in the [1Cu2+ : 3Cu+] redox state, which is redox inert and requires prolonged incubation under reductive conditions to be activated. In this work, we report, for the first time, the isolation of N2OR from M. hydrocarbonoclasticus in the ‘purple’ form, in which the CuZ centre is in the oxidized [2Cu2+ : 2Cu+] redox state and is redox active. This form of the enzyme was isolated in the presence of oxygen from a microaerobic culture in the presence of nitrate and also from a strictly anaerobic culture. The purple form of the enzyme was biochemically characterized and was shown to be a redox active species, although it is still catalytically non-competent, as its specific activity is lower than that of the activated fully reduced enzyme and comparable with that of the enzyme with the CuZ centre in either the [1Cu2+ : 3Cu+] redox state or in the redox inactive CuZ* state. PMID:22451106

  6. Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

    1996-01-08

    This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

  7. Denitrifying bacterial communities affect current production and nitrous oxide accumulation in a microbial fuel cell.

    Science.gov (United States)

    Vilar-Sanz, Ariadna; Puig, Sebastià; García-Lledó, Arantzazu; Trias, Rosalia; Balaguer, M Dolors; Colprim, Jesús; Bañeras, Lluís

    2013-01-01

    The biocathodic reduction of nitrate in Microbial Fuel Cells (MFCs) is an alternative to remove nitrogen in low carbon to nitrogen wastewater and relies entirely on microbial activity. In this paper the community composition of denitrifiers in the cathode of a MFC is analysed in relation to added electron acceptors (nitrate and nitrite) and organic matter in the cathode. Nitrate reducers and nitrite reducers were highly affected by the operational conditions and displayed high diversity. The number of retrieved species-level Operational Taxonomic Units (OTUs) for narG, napA, nirS and nirK genes was 11, 10, 31 and 22, respectively. In contrast, nitrous oxide reducers remained virtually unchanged at all conditions. About 90% of the retrieved nosZ sequences grouped in a single OTU with a high similarity with Oligotropha carboxidovorans nosZ gene. nirS-containing denitrifiers were dominant at all conditions and accounted for a significant amount of the total bacterial density. Current production decreased from 15.0 A · m(-3) NCC (Net Cathodic Compartment), when nitrate was used as an electron acceptor, to 14.1 A · m(-3) NCC in the case of nitrite. Contrarily, nitrous oxide (N2O) accumulation in the MFC was higher when nitrite was used as the main electron acceptor and accounted for 70% of gaseous nitrogen. Relative abundance of nitrite to nitrous oxide reducers, calculated as (qnirS+qnirK)/qnosZ, correlated positively with N2O emissions. Collectively, data indicate that bacteria catalysing the initial denitrification steps in a MFC are highly influenced by main electron acceptors and have a major influence on current production and N2O accumulation.

  8. Estimation of methane and nitrous oxide emissions from paddy fields in Taiwan

    International Nuclear Information System (INIS)

    Yang, Shang-Shyng; Lai, Chao-Ming; Chang, Hsiu-Lan; Chang, Ed-Huan; Wei, Chia-Bei

    2009-01-01

    To investigate the greenhouse gases emissions from paddy fields, methane and nitrous oxide emissions were estimated with the local measurement and the IPCC method during 1990-2006 in Taiwan. Annual methane emission ranged from 9001 to 14,980 ton in the first crop season for 135,314-242,298 ha of paddy fields, and it was between 16,412 and 35,208 ton for 101,710-211,968 ha in the second crop season with the local measurement for intermittent irrigation. The value ranged from 31,122 to 55,729 ton of methane emission in the first crop season, and it was between 29,493 and 61,471 ton in the second crop season with the IPCC guideline for continuous flooding. Annual nitrous oxide emission from paddy fields was between 371 and 728 ton in the first crop season, and the value ranged from 163 to 365 ton in the second crop season with the local measurement. Methane emission from paddy fields in Taiwan for intermittent irrigation was only 26.72-28.92%, 55.65-57.32% and 41.19-43.10% with the IPCC guidelines for continuous flooding and mean temperature of transplanting stage in the first crop, the second crop and total paddy fields, respectively. The values were 53.44-57.84%, 111.29-114.55% and 82.38-86.20% with the IPCC guidelines for single aeration and mean temperature of transplanting stage, respectively; and the values were 133.60-144.61%, 282.56-286.62% and 205.96-215.49% with the IPCC guidelines for multiple aeration and mean temperature of transplanting stage, respectively. Intermittent irrigation in paddy fields reduces methane emission significantly; appropriate application of nitrogen fertilizer and irrigation in paddy fields also decreases nitrous oxide emission. (author)

  9. Molecular identification of the mode of interaction of nitrous oxide with the opiate receptor system

    Energy Technology Data Exchange (ETDEWEB)

    Wallar, D D

    1985-01-01

    The discovery of the opioid receptors in 1973 has led to a great deal of in vivo and in vitro research in order to understand the mechanism of binding of endogenous and synthetic opiate ligands. The use of nitrous oxide (N/sub 2/O) in anaesthesia is well documented. However, at lower concentrations N/sub 2/O produces analgesia. In 1976, it was reported that N/sub 2/O analgesia in man could be modified by the opiate antagonist naloxone. This clearly linked nitrous oxide analgesia to the opioid receptor system. It is the purpose of this dissertation to examine the molecular mechanism of action of N/sub 2/O at the opioid receptor through the use of in vitro binding studies. In addition, a model of the opioid receptor will be proposed. The following radiolabelled ligands were used in classical competitive binding assays to determine K (sub D),B(sub max), and IC/sub 50/ values in the presence of nitrous oxide and other control gases: dihydromorphine, N-allyl-N-normetazocine (SKF 10,047), and ethylketocyclazocine, for putative ..mu.., sigma and kappa opioid binding sites, respectively. All assays were performed using rat forebrain homogenates suspended in buffer previously saturated with the gas. Results indicate that N/sub 2/O differentially affects the binding kinetics of dihydromorphine. The binding kinetics of SKF 10,047 or ethylketocyclazocine were not altered significantly by N/sub 2/O indicating that N/sub 2/O is specific in its effects for the putative ..mu..-binding site. It is suggested that N/sub 2/O exerts its analgesic effects by perturbation of protein/lipid interactions within a multiple binding site opioid receptor complex.

  10. Statistical analysis of nitrous oxide emission factors from pastoral agriculture field trials conducted in New Zealand

    International Nuclear Information System (INIS)

    Kelliher, F.M.; Cox, N.; Weerden, T.J. van der; Klein, C.A.M. de; Luo, J.; Cameron, K.C.; Di, H.J.; Giltrap, D.; Rys, G.

    2014-01-01

    Between 11 May 2000 and 31 January 2013, 185 field trials were conducted across New Zealand to measure the direct nitrous oxide (N 2 O) emission factors (EF) from nitrogen (N) sources applied to pastoral soils. The log(EF) data were analysed statistically using a restricted maximum likelihood (REML) method. To estimate mean EF values for each N source, best linear unbiased predictors (BLUPs) were calculated. For lowland soils, mean EFs for dairy cattle urine and dung, sheep urine and dung and urea fertiliser were 1.16 ± 0.19% and 0.23 ± 0.05%, 0.55 ± 0.19% and 0.08 ± 0.02% and 0.48 ± 0.13%, respectively, each significantly different from one another (p 12°, mean EFs were significantly lower. Thus, urine and dung EFs should be disaggregated for sheep and cattle as well as accounting for terrain. -- Highlights: • Nitrous oxide emission factors (EFs) for pastoral soils measured in 185 field trials. • For lowland, the mean (±standard error) urea nitrogen fertiliser EF was 0.5 ± 0.1%. • For lowland, mean dairy cattle urine and dung EFs were 1.2 and 0.2%, respectively. • For lowland, mean sheep urine and dung EFs were 0.6 and 0.1%, respectively. • For pastoral soils in terrain with slopes >12°, mean EFs were significantly lower. -- From 185 field trials, mean nitrous oxide emission factors for pastoral soils were 0.1% for sheep dung up to 1.2% for dairy cattle urine, while that for urea fertiliser was 0.5%

  11. The Dynamics of Nitrous Oxide Emission from the Use of Mineral Fertilizers in Russia

    Directory of Open Access Journals (Sweden)

    A AA. Romanovskaya

    2001-01-01

    Full Text Available The intensity of nitrous oxide (N2O emission was considered based on literature data on the single input of mineral N (nitrogen fertilizers into different agricultural soil types in Russia. Ambient environmental factors exert a combined effect on the process of gaseous nitrogen formation from fertilizers applied. To reduce the uncertainty of estimates as much as possible, only experimental results obtained under conditions similar to natural were selected for the assessments. Mineral nitric fertilizers were applied to soil at a rate of 40 to 75 kg/ha and the N2O emissions were measured for approximately 140 days. Daily average emission values varied from 0.08 to 0.45% of fertilizer nitrogen. Correspondingly, 1.26 and 2.38% of fertilizer nitrogen were emitted as N2O from chernozems and soddy podzols. In 1990, the use of fertilizers in Russian agricultural practices for 53 Gg N2O-N, which equates to approximately 6.1% of global nitrous oxide emissions from nitric fertilizers. Later, the emission dropped because of a decrease in the input of nitric fertilizers to agricultural crops, and in 1998, it constituted just 20.5% of the 1990 level. In the period from 2008 to 2012, the nitrous oxide emission is expected to vary from 0.5 to 65.0 Gg N2O-N due to possible changes in national agricultural development. In the most likely scenario, the use of mineral fertilizers in Russia will account for approximately 34 to 40 Gg N2O-N emissions annually from 2008�2012.

  12. Methane and nitrous oxide: Methods in national emissions inventories and options for control

    Energy Technology Data Exchange (ETDEWEB)

    Van Amstel, A.R. (ed.)

    1993-07-01

    The UN Framework Convention on Climate Change signed in Rio de Janeiro, Brazil, calls for the return of anthropogenic emissions of greenhouse gases to their 1990 levels by the year 2000 in industrialized countries. It also calls for a monitoring of the emissions of greenhouse gases. It is important that reliable and scientifically credible national inventories are available for the international negotiations. Therefore a consistent methodology and a transparent reporting format is needed. The title workshop had two main objectives: (1) to support the development a methodology and format for national emissions inventories of greenhouse gases by mid 1993, as coordinated by the Science Working Group of the IPCC and the OECD; and (2) the development of technical options for reduction of greenhouse gases and the assessment of the socio-economic feasibility of these options. The workshop consisted of key note overview presentations, and two rounds of working group sessions, each covering five parallel sessions on selected sources. In the first round of each working group session the literature, existing methods for methane and nitrous oxide inventories, and the OECD/IPCC guidelines have been addressed. Then, in the second round, options for emission reductions have been discussed, as well as their socio-economic implications. The methane sources discussed concern oil and gas, coal mining, ruminants, animal waste, landfills and sewage treatment, combustion and industry, rice production and wetlands, biomass burning. The nitrous oxide sources discussed are agricultural soils and combustion and industry. The proceedings on methane comprise 16 introductory papers and 7 papers on the results of the working groups, while in part two four introductory papers and two papers on the results of working groups on nitrous oxide are presented. In part three future emission reduction policy options are discussed. Finally, 16 poster contributions are included

  13. Use and perception of nitrous oxide sedation by French dentists in private practice: a national survey.

    Science.gov (United States)

    Vilanova-Saingery, C; Bailleul-Forestier, I; Vaysse, F; Vergnes, J-N; Marty, M

    2017-12-01

    The aim of this national survey was to record the use of nitrous oxide and the perceptions of French dental practitioners to this form of sedation. The use of nitrous oxide sedation (NOS) has been authorised in private dental practice in France since December 2009 but, to date, no study implementing both quantitative and qualitative methods has explored such use. The data were collected using a Google Forms questionnaire. A mixed methodology was used for data analysis: a quantitative approach to explore the use of conscious sedation and a qualitative thematic approach (using Nvivo software) to determine the practitioner's perception of it. Responses were collected from 225 practitioners (19% of the target population of 1185). Most of the responders were trained in NOS use in private dental clinics. Seventy-three percent of those who trained privately actually used NOS, compared to 53% of those trained at university (p-value = 0.0052). Above all, NOS was used for children requiring restorative dentistry. The average price of the sedation was 50 Euros and it lasted, on average, for 37 min. The qualitative and thematic analysis revealed the financial and technical difficulties of implementing NOS in private practice. However, it also showed the benefits and pleasure associated with NOS use. This statistical survey of French dental practitioners offers an insight of the current state of the use of conscious sedation with nitrous oxide in private general dental practice in France. It also includes the first report of dental practitioners' perceptions of NOS use and may lead to a better understanding of the reasons why sedation is sometimes not used in private practice.

  14. Nitrous oxide for procedural analgesia at home in a child with epidermolysis bullosa.

    Science.gov (United States)

    Ingelmo, Pablo; Wei, Andrew; Rivera, Gonzalo

    2017-07-01

    Epidermolysis bullosa comprises a range of conditions characterized by fragile skin with painful blistering induced by minor trauma and friction. The Dowling-Meara variant is a severe form characterized by disseminated painful blistering requiring lifelong skin and wound care. The natural history of the disease is characterized by a chronic course that tends to improve with advancing age. Various multimodal analgesic strategies have been proposed for painful procedures in children with epidermolysis bullosa. In this case report, we describe the use of nitrous oxide for pain control at home of blister treatments in a 4-year-old child with the Dowling-Meara variant. © 2017 John Wiley & Sons Ltd.

  15. Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark

    DEFF Research Database (Denmark)

    Schelde, Kirsten; Cellier, P; Bertolini, T

    2012-01-01

    Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O...... yr−1) during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application. Our findings confirm the importance of weather conditions as well as nitrogen management on N2O fluxes....

  16. Dynamic modelling of nitrous oxide emissions from three Swedish sludge liquor treatment systems

    DEFF Research Database (Denmark)

    Lindblom, E.; Arnell, M.; Flores-Alsina, X.

    2014-01-01

    The objective of this paper is to model the dynamics and validate the results of nitrous oxide (N2O)emissions from three Swedish nitrifying/denitrifying, nitritation and anammox systems treating real anaerobic digester sludge liquor. The Activated Sludge Model No. 1 is extended to describe N2O...... production by both heterotrophic and autotrophic denitrification. In addition, mass transfer equations are implemented to characterize the dynamics of N2O in the water and the gas phases.The biochemical model is simulated and validated for two hydraulic patterns: (1) a sequencing batch reactor; and, (2...

  17. Soil nitrate reducing processes drivers, mechanisms for spatial variation, and significance for nitrous oxide production

    OpenAIRE

    Giles, M.; Morley, N.; Baggs, E.M.; Daniell, T.J.

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium\\ud (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for\\ud the loss of nitrate (NO−\\ud 3 ) and production of the potent greenhouse gas, nitrous oxide (N2O).\\ud A number of factors are known to control these processes, including O2 concentrations and\\ud moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms\\ud responsible for the ...

  18. Methane and Nitrous Oxide Emissions from Agriculture on a Regional Scale

    OpenAIRE

    Agnieszka Wysocka-Czubaszek; Robert Czubaszek; Sławomir Roj-Rojewski; Piotr Banaszuk

    2018-01-01

    Nowadays, agriculture has to meet the growing food demand together with high requirements of environmental protection, especially regarding the climate change. The greenhouse gas emissions differ not only on a global, but also on a regional scale, and mitigation strategies are effective when they are adapted properly. Therefore, the aim of this paper is to present the results of methane (CH4) and nitrous oxide (N2O) emissions inventory on a regional level in Poland in years 1999-2015. The CH4...

  19. Powerful greenhouse gas nitrous oxide adsorption onto intrinsic and Pd doped Single walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Yoosefian, Mehdi, E-mail: m.yoosefian@kgut.ac.ir

    2017-01-15

    Highlights: • Investigation of the adsorption of Nitrous oxide on SWCNT and Pd/SWCNT. • Nitrous oxide adsorbed on Pd/SWCNT system demonstrates a strong adsorption. • The Pd/SWCNT is potential sensor for the Nitrous oxide gaseous molecule detection. - Abstract: Density functional studies on the adsorption behavior of nitrous oxide (N{sub 2}O) onto intrinsic carbon nanotube (CNT) and Pd-doped (5,5) single-walled carbon nanotube (Pd-CNT) have been reported. Introduction of Pd dopant facilitates in adsorption of N{sub 2}O on the otherwise inert nanotube as observed from the adsorption energies and global reactivity descriptor values. Among three adsorption features of N{sub 2}O onto CNT, the horizontal adsorption with E{sub ads} = −0.16 eV exhibits higher adsorption energy. On the other hand the Pd-CNT exhibit strong affinity toward gas molecule and would cause a huge increase in N{sub 2}O adsorption energies. Chemical and electronic properties of CNT and Pd-CNT in the absence and presence of N{sub 2}O were investigated. Adsorption of N{sub 2}O gas molecule would affect the electronic conductance of Pd-CNT that can serve as a signal of gas sensors and the increased energy gaps demonstrate the formation of more stable systems. The atoms in molecules (AIM) theory and the natural bond orbital (NBO) calculations were performed to get more details about the nature and charge transfers in intermolecular interactions within adsorption process. As a final point, the density of states (DOSs) calculations was achieved to confirm previous results. According to our results, intrinsic CNT cannot act as a suitable adsorbent while Pd-CNT can be introduced as novel detectable complex for designing high sensitive, fast response and high efficient carbon nanotube based gas sensor to detect N{sub 2}O gas as an air pollutant. Our results could provide helpful information for the design and fabrication of the N{sub 2}O sensors.

  20. Combined cannabis/methaqualone withdrawal treated with psychotropic analgesic nitrous oxide.

    Science.gov (United States)

    Gillman, Mark A; Harker, Nadine; Lichtigfeld, Frederick J

    2006-07-01

    This article reports the first single-blind study using psychotropic analgesic nitrous oxide (PAN) for treating acute withdrawal states following the abuse of methaqualone combined and smoked with cannabis. Smoked methaqualone combined with cannabis is called "white pipe" (WP). South Africa is the only country in the world where WP is a major form of substance abuse. This article demonstrates in 101 consecutively treated patients given placebo (100% oxygen) followed by PAN that this therapy produced a measurable therapeutic effect (more than 50% improvement) in 87 patients. This study confirms that WP is a form of substance abuse confined mainly to young adult male subjects.

  1. Clinical experience with TENS and TENS combined with nitrous oxide-oxygen. Report of 371 patients.

    OpenAIRE

    Quarnstrom, F. C.; Milgrom, P.

    1989-01-01

    Transcutaneous electrical nerve stimulation (TENS) alone or TENS combined with nitrous oxide-oxygen (N2O) was administered for restorative dentistry without local anesthesia to 371 adult patients. A total of 55% of TENS alone and 84% of TENS/N2O visits were rated successful. A total of 53% of TENS alone and 82% of TENS/N2O patients reported slight or no pain. In multivariable analyses, pain reports were related to the anesthesia technique and patient fear and unrelated to sex, race, age, toot...

  2. Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

    Science.gov (United States)

    Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

    2012-05-01

    A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

  3. Environmental and microbial factors influencing methane and nitrous oxide fluxes in Mediterranean cork oak woodlands: trees make a difference.

    Science.gov (United States)

    Shvaleva, Alla; Siljanen, Henri M P; Correia, Alexandra; Costa E Silva, Filipe; Lamprecht, Richard E; Lobo-do-Vale, Raquel; Bicho, Catarina; Fangueiro, David; Anderson, Margaret; Pereira, João S; Chaves, Maria M; Cruz, Cristina; Martikainen, Pertti J

    2015-01-01

    Cork oak woodlands (montado) are agroforestry systems distributed all over the Mediterranean basin with a very important social, economic and ecological value. A generalized cork oak decline has been occurring in the last decades jeopardizing its future sustainability. It is unknown how loss of tree cover affects microbial processes that are consuming greenhouse gases in the montado ecosystem. The study was conducted under two different conditions in the natural understory of a cork oak woodland in center Portugal: under tree canopy (UC) and open areas without trees (OA). Fluxes of methane and nitrous oxide were measured with a static chamber technique. In order to quantify methanotrophs and bacteria capable of nitrous oxide consumption, we used quantitative real-time PCR targeting the pmoA and nosZ genes encoding the subunit of particulate methane mono-oxygenase and catalytic subunit of the nitrous oxide reductase, respectively. A significant seasonal effect was found on CH4 and N2O fluxes and pmoA and nosZ gene abundance. Tree cover had no effect on methane fluxes; conversely, whereas the UC plots were net emitters of nitrous oxide, the loss of tree cover resulted in a shift in the emission pattern such that the OA plots were a net sink for nitrous oxide. In a seasonal time scale, the UC had higher gene abundance of Type I methanotrophs. Methane flux correlated negatively with abundance of Type I methanotrophs in the UC plots. Nitrous oxide flux correlated negatively with nosZ gene abundance at the OA plots in contrast to that at the UC plots. In the UC soil, soil organic matter had a positive effect on soil extracellular enzyme activities, which correlated positively with the N2O flux. Our results demonstrated that tree cover affects soil properties, key enzyme activities and abundance of microorganisms and, consequently net CH4 and N2O exchange.

  4. Nitrous Oxide Abuse and Vitamin B12 Action in a 20-Year-Old Woman: A Case Report.

    Science.gov (United States)

    Duque, Miriam Andrea; Kresak, Jesse L; Falchook, Adam; Harris, Neil S

    2015-01-01

    Herein, we report a case of a 20-year-old (ethnicity not reported) woman with a history of nitrous oxide abuse and clinical symptoms consistent with spinal cord subacute combined degeneration with associated low serum concentrations of vitamin B12, elevated methylmalonic acid levels, and radiologic evidence of demyelination of the dorsal region of the spinal column. The health of the patient improved dramatically with B12 supplementation. In this case, we discuss the interaction of nitrous oxide with the enzymatic pathways involved in the biochemistry of vitamin B12. Copyright© by the American Society for Clinical Pathology (ASCP).

  5. Nitrous oxide emissions from European agriculture - an analysis of variability and drivers of emissions from field experiments

    DEFF Research Database (Denmark)

    Rees, R M; Agustin, J; Alberti, G

    2013-01-01

    Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot-based experime......Nitrous oxide emissions from a network of agricultural experiments in Europe were used to explore the relative importance of site and management controls of emissions. At each site, a selection of management interventions were compared within replicated experimental designs in plot...

  6. Microbial resource management for the mitigation of nitrous oxide emissions from the Partial Nitritation- Anammox process

    DEFF Research Database (Denmark)

    Blum, Jan-Michael

    Urban wastewater treatment plants are designed to remove pathogens and pollutants from wastewater in order to provide sanitation and to protect receiving water bodies from eutrophication. Reactive nitrogen, mainly in the form of ammonium, is one of the components in wastewater that is converted...... to dinitrogen gas during treatment. The Partial Nitritation-Anammox process (PNA) uses the capacity of autotrophic aerobic and anaerobic ammonia oxidizing bacteria (AOB and AnAOB) to perform this task. The process is mainly applied to treat ammonium-rich wastewater streams with low concentrations of organic...... with the specific ammonia removal rate, while during non-aerated phases net N2O production rates were positively correlated with the nitrite concentration (NO2-). Operation of PNA at reduced specific ammonia removal rates is, therefore, a feasible strategy to mitigate N2O emissions. However, when high ammonium...

  7. Community Structure of Ammonia-Oxidizing Archaea and Ammonia-Oxidizing Bacteria in Soil Treated with the Insecticide Imidacloprid

    Directory of Open Access Journals (Sweden)

    Mariusz Cycoń

    2015-01-01

    Full Text Available The purpose of this experiment was to assess the effect of imidacloprid on the community structure of ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB in soil using the denaturing gradient gel electrophoresis (DGGE approach. Analysis showed that AOA and AOB community members were affected by the insecticide treatment. However, the calculation of the richness (S and the Shannon-Wiener index (H values for soil treated with the field rate (FR dosage of imidacloprid (1 mg/kg soil showed no changes in measured indices for the AOA and AOB community members. In turn, the 10*FR dosage of insecticide (10 mg/kg soil negatively affected the AOA community, which was confirmed by the decrease of the S and H values in comparison with the values obtained for the control soil. In the case of AOB community, an initial decline followed by the increase of the S and H values was obtained. Imidacloprid decreased the nitrification rate while the ammonification process was stimulated by the addition of imidacloprid. Changes in the community structure of AOA and AOB could be due to an increase in the concentration of N-NH4+, known as the most important factor which determines the contribution of these microorganisms to soil nitrification.

  8. The inhibitory effects of free ammonia on ammonia oxidizing bacteria and nitrite oxidizing bacteria under anaerobic condition.

    Science.gov (United States)

    Qian, Wenting; Peng, Yongzhen; Li, Xiyao; Zhang, Qiong; Ma, Bin

    2017-11-01

    The free ammonia (FA) inhibition on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under anaerobic condition was investigated in this study. The results indicated that NOB was more sensitive to the FA anaerobic treatment than AOB. The FA anaerobic inhibition on nitrifier gradually heightened with the increase of FA concentration. Accompanied with FA concentration increase from 0 to 16.82mgNH 3 -N·L -1 (the highest concentration adopted in this study), the activity of AOB reduced by 15.9%, while NOB decreased by 29.2%. After FA anaerobic treatment, nitrite was accumulated during nitrification. However, the nitrite accumulation disappeared on the sixth cycle of activity recovery tests with excessive aeration. Based on this result, a novel strategy for achieving nitritation is proposed, which involves recirculating a portion of the activated sludge through a side-line sludge treatment unit, where the sludge is subjected to treatment with FA under anaerobic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Contributions of ammonia-oxidizing archaea and bacteria to nitrification in Oregon forest soils

    Science.gov (United States)

    Xinda Lu; Peter J. Bottomley; David D. Myrold

    2015-01-01

    Ammonia oxidation, the first step of nitrification, is mediated by both ammonia-oxidizing archaea (AOA) and bacteria (AOB); however, the relative contributions of AOA and AOB to soil nitrification are not well understood. In this study we used 1-octyne to discriminate between AOA-and AOB-supported nitrifi-cation determined both in soil-water slurries and in unsaturated...

  10. Nitrous oxide production pathways in a partial nitritation-anammox reactor: Isotopic evidence for nitrous oxide production associated anaerobic ammonium oxidation?

    Science.gov (United States)

    Wunderlin, P.; Harris, E. J.; Joss, A.; Emmenegger, L.; Kipf, M.; Mohn, J.; Siegrist, H.

    2014-12-01

    Nitrous oxide (N2O) is a strong greenhouse gas and a major sink for stratospheric ozone. In biological wastewater treatment N2O can be produced via several pathways. This study investigates the dynamics of N2O emissions from a nitritation-anammox reactor, and links its interpretation to the nitrogen and oxygen isotopic signature of the emitted N2O. A 400-litre single-stage nitritation-anammox reactor was operated and continuously fed with digester liquid. The isotopic composition of N2O emissions was monitored online with quantum cascade laser absorption spectroscopy (QCLAS; Aerodyne Research, Inc.; Waechter et al., 2008). Dissolved ammonium and nitrate were monitored online (ISEmax, Endress + Hauser), while nitrite was measured with test strips (Nitrite-test 0-24mgN/l, Merck). Table 1. Summary of experiments conducted to understand N2O emissions Experimental conditions O2[mgO2/L] NO2-[mgN/L] NH4+[mgN/L] N2O/NH4+[%] Normal operation production pathway, which is hypothesized to be mediated by anammox activity (Figure 1). A less likely explanation is that the SP of N2O was increased by partial N2O reduction by heterotrophic denitrification. Various experiments were conducted to further investigate N2O formation pathways in the reactor. Our data reveal that N2O emissions increased when reactor operation was not ideal, for example when dissolved oxygen was too high (Table 1). SP measurements confirmed that these N2O peaks were due to enhanced nitrifier denitrification, generally related to nitrite build-up in the reactor (Figure 1; Table 1). Overall, process control via online N2O monitoring was confirmed to be an ideal method to detect imbalances in reactor operation and regulate aeration, to ensure optimal reactor conditions and minimise N2O emissions. ReferencesWaechter H. et al. (2008) Optics Express, 16: 9239-9244. Wunderlin, P et al. (2013) Environmental Science & Technology 47: 1339-1348.

  11. The oxidation of uranium(IV) ions by nitrous acid in 30% tri-butyl phosphate

    International Nuclear Information System (INIS)

    Koltunov, V.S.; Marchenko, V.I.; Savilova, O.A.; Dvoeglazov, K.N.; Taylor, R.J.

    2004-01-01

    The kinetics of the oxidation of U(IV) ions by nitrous acid in a 30% TBP solution have been determined. The rate equation was found to be: - d[U(IV)] / dt = k 2a [U(IV)][HNO 2 ][HNO 3 ][H 2 O] / [HNO 3 ] 2 + β 3 [HNO 3 ][H 2 O] + β 4 [H 2 O] 2 , where, k 2a = 0.405 ± 0.055 M -1 min -1 at 55 C (β 3 ∼ 0.08; β 4 ∼ 0.007) and the activation energy was E = 112 ± 17 kJ mol -1 . The reaction mechanism appeared to involve interaction with the 1 st hydrolysis product of U(IV)-UOH 3+ . The data is compared with a previous study of the nitric acid oxidation of U(IV) in 30% TBP. This reaction is autocatalytic due to the formation of nitrous acid during the reaction. The kinetics of the decomposition of HNO 2 in 30% TBP (in the absence of U(IV)) have also been reported. (orig.)

  12. Do lagoons near concentrated animal feeding operations promote nitrous oxide supersaturation?

    International Nuclear Information System (INIS)

    Makris, Konstantinos C.; Sarkar, Dibyendu; Andra, Syam S.; Bach, Stephan B.H.; Datta, Rupali

    2009-01-01

    Animal wastewater lagoons nearby concentrated animal feeding operations (CAFOs) represent the latest tendency in global animal farming, severely impacting the magnitude of greenhouse gas emissions, including nitrous oxide (N 2 O). We hypothesized that lagoon wastewater could be supersaturated with N 2 O as part of incomplete microbial nitrification/denitrification processes, thereby regulating the N 2 O partitioning in the gaseous phase. The objectives of this study were: (i) to investigate the magnitude of dissolved N 2 O concentrations in the lagoon; and (ii) to determine the extent to which supersaturation of N 2 O occurs in wastewater lagoons. Dissolved N 2 O concentrations in the wastewater samples were high, ranging from 0.4 to 40.5 μg N 2 O mL -1 . Calculated dissolved N 2 O concentrations from the experimentally measured partition coefficients were much greater than those typically expected in aquatic systems ( 2 O mL -1 ). Knowledge of the factors controlling the magnitude of N 2 O supersaturation could potentially bridge mass balance differences between in situ measurements and global N 2 O models. - Supersaturation of nitrous oxide may occur in lagoons near concentrated animal feeding operations.

  13. Biological groundwater denitrification systems: Lab-scale trials aimed at nitrous oxide production and emission assessment.

    Science.gov (United States)

    Capodici, Marco; Avona, Alessia; Laudicina, Vito Armando; Viviani, Gaspare

    2018-07-15

    Bio-trenches are a sustainable option for treating nitrate contamination in groundwater. However, a possible side effect of this technology is the production of nitrous oxide, a greenhouse gas that can be found both dissolved in the liquid effluent as well as emitted as off gas. The aim of this study was to analyze NO 3 - removal and N 2 O production in lab-scale column trials. The column contained olive nut as organic carbon media. The experimental study was divided into three phases (I, II and III) each characterized by different inlet NO 3 - concentrations (30, 50, 75mgNO 3 -NL -1 respectively). Sampling ports deployed along the length of the column allowed to observe the denitrification process as well as the formation and consumption of intermediate products, such as nitrite (NO 2 - ) and nitrous oxide (N 2 O). In particular, it was observed that N 2 O production represent only a small fraction of removed NO 3 - during Phase I and II, both for dissolved (0.007%) and emitted (0.003%) phase, and it was recorded a high denitrification efficiency, over 99%. Nevertheless, significantly higher values were recorded for Phase 3 concerning emitted phase (0.018%). This fact is due to increased inlet concentration which resulted in a carbon limitation and in a consequent decrease in denitrification efficiency (76%). Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Nitrous oxide production by nitrification and denitrification in the Eastern Tropical South Pacific oxygen minimum zone

    Science.gov (United States)

    Ji, Qixing; Babbin, Andrew R.; Jayakumar, Amal; Oleynik, Sergey; Ward, Bess B.

    2015-12-01

    The Eastern Tropical South Pacific oxygen minimum zone (ETSP-OMZ) is a site of intense nitrous oxide (N2O) flux to the atmosphere. This flux results from production of N2O by nitrification and denitrification, but the contribution of the two processes is unknown. The rates of these pathways and their distributions were measured directly using 15N tracers. The highest N2O production rates occurred at the depth of peak N2O concentrations at the oxic-anoxic interface above the oxygen deficient zone (ODZ) because slightly oxygenated waters allowed (1) N2O production from both nitrification and denitrification and (2) higher nitrous oxide production yields from nitrification. Within the ODZ proper (i.e., anoxia), the only source of N2O was denitrification (i.e., nitrite and nitrate reduction), the rates of which were reflected in the abundance of nirS genes (encoding nitrite reductase). Overall, denitrification was the dominant pathway contributing the N2O production in the ETSP-OMZ.

  15. The Effect of Nitrous Oxide Psychosedation on Pantographic Tracings; A preliminary study

    International Nuclear Information System (INIS)

    Fareed, Kamal

    1989-01-01

    The form and reproducibility of pantographic tracings under the influence of relaxant drugs and in patients with muscle dysfunction and TMJ disorders, tend to emphasize the dominance of the neuromuscular factors. The purpose of this study was to demonstrate the effect of nitrous oxide induced psychosedation, on the reproducibility of pantographic tracings of border movements of the mandible. This study included four male subjects (with no signs and symptoms of muscular dysfunction and temporomandibular joint problems). Operator guided border tracings were recorded using the Denar pantograph. Three sets of tracings were recorded: (1) three tracings prior to sedation (Tracing I); (2) one tracing prior to sedation and two after sedation (Tracing II); (3) three tracings after psychosedation (Tracing III). The coincidence of tracings I, II, and 111 were statistically analyzed applying the chi-square (X2) analysis. There was a significant difference in the coincidence of tracings between Tracings 1 and II (X2 = 14.892). There was no significant difference in the coincidence of tracings between Tracings I and III (X2 = 1.338). This suggests that nitrous oxide psychosedation produces a centrally induced relaxation of the musculature, by possibly eliminating the extraneous anxiety producing factors. (author)

  16. The emission of nitrous oxide upon wetting a rice soil following a dry season fallow

    Science.gov (United States)

    Byrnes, B. H.; Holt, L. S.; Austin, E. R.

    1993-12-01

    A greenhouse experiment was conducted to measure nitrous oxide (N2O) emissions from a soil, which had been planted to flooded transplanted rice, as it was rewetted to simulate the end of a dry season fallow period. The pots of soil had been cropped to transplanted rice with two commonly used nitrogen (N) fertilizer treatments and a control, and the soil had been puddled before transplanting. Large amounts of nitrate N accumulated in the soils during the dry season fallow, and the N fertilizers applied to the previous crop had little effect on nitrate accumulation. There was little N2O emission during the nitrification period. With water additions meant to simulate rainfall events at the beginning of a wet season, the soil redox dropped slightly, and large amounts of N2O began to be emitted. Large emissions began 5 days after each of the two simulated rainy season watering events and stopped abruptly at soil saturation, even though considerable amounts of nitrate still remained in the soil after saturation. Total measured emissions amounted to 6 to 7 kg N2O-N ha-1 for the period. Although these measurements were made in a system which may have favored nitrate accumulation, they are the first known measurements of N2O made from a rice soil as it is wetted. Nitrous oxide emitted from the flooding of rice soils that have accumulated nitrate during a dry season fallow may be a major source of N2O additions to the atmosphere.

  17. Abiotic mechanism for the formation of atmospheric nitrous oxide from ammonium nitrate.

    Science.gov (United States)

    Rubasinghege, Gayan; Spak, Scott N; Stanier, Charles O; Carmichael, Gregory R; Grassian, Vicki H

    2011-04-01

    Nitrous oxide (N2O) is an important greenhouse gas and a primary cause of stratospheric ozone destruction. Despite its importance, there remain missing sources in the N2O budget. Here we report the formation of atmospheric nitrous oxide from the decomposition of ammonium nitrate via an abiotic mechanism that is favorable in the presence of light, relative humidity and a surface. This source of N2O is not currently accounted for in the global N2O budget. Annual production of N2O from atmospheric aerosols and surface fertilizer application over the continental United States from this abiotic pathway is estimated from results of an annual chemical transport simulation with the Community Multiscale Air Quality model (CMAQ). This pathway is projected to produce 9.3(+0.7/-5.3) Gg N2O annually over North America. N2O production by this mechanism is expected globally from both megacities and agricultural areas and may become more important under future projected changes in anthropogenic emissions.

  18. The impact of Southwest Airline's contribution to atmospheric Carbon Dioxide and Nitrous Oxide totals

    Science.gov (United States)

    Wilkerson, Cody L.

    Over the last century, aviation has grown to become an economical juggernaut. The industry creates innovation, connects people, and maintains a safety goal unlike any other field. However, as the world becomes more populated with technology and individuals, a general curiosity as to how human activity effects the planet is becoming of greater interest. This study presents what one domestic airline in the United States, Southwest Airlines, contributes to the atmospheric make-up of the planet. Utilizing various sources of quantifiable data, an outcome was reached that shows the amount of Carbon Dioxide and Nitrous Oxide produced by Southwest Airlines from 2002 to 2013. This topic was chosen due to the fact that there are no real quantifiable values of emission statistics from airlines available to the public. Further investigation allowed for Southwest Airlines to be compared to the overall Carbon Dioxide and Nitrous Oxide contributions of the United States for the year 2011. The results showed that with the absence of any set standard on emissions, it is vital that one should be established. The data showed that the current ICAO standard emission values showed a higher level of emissions than when Southwest Airline's fleet was analyzed using their actual fleet mix.

  19. The history of aerobic ammonia oxidizers: from the first discoveries to today.

    Science.gov (United States)

    Monteiro, Maria; Séneca, Joana; Magalhães, Catarina

    2014-07-01

    Nitrification, the oxidation of ammonia to nitrite and nitrate, has long been considered a central biological process in the global nitrogen cycle, with its first description dated 133 years ago. Until 2005, bacteria were considered the only organisms capable of nitrification. However, the recent discovery of a chemoautotrophic ammonia-oxidizing archaeon, Nitrosopumilus maritimus, changed our concept of the range of organisms involved in nitrification, highlighting the importance of ammonia-oxidizing archaea (AOA) as potential players in global biogeochemical nitrogen transformations. The uniqueness of these archaea justified the creation of a novel archaeal phylum, Thaumarchaeota. These recent discoveries increased the global scientific interest within the microbial ecology society and have triggered an analysis of the importance of bacterial vs archaeal ammonia oxidation in a wide range of natural ecosystems. In this mini review we provide a chronological perspective of the current knowledge on the ammonia oxidation pathway of nitrification, based on the main physiological, ecological and genomic discoveries.

  20. Differential contributions of ammonia oxidizers and nitrite oxidizers to nitrification in four paddy soils

    Science.gov (United States)

    Wang, Baozhan; Zhao, Jun; Guo, Zhiying; Ma, Jing; Xu, Hua; Jia, Zhongjun

    2015-01-01

    Rice paddy fields are characterized by regular flooding and nitrogen fertilization, but the functional importance of aerobic ammonia oxidizers and nitrite oxidizers under unique agricultural management is poorly understood. In this study, we report the differential contributions of ammonia-oxidizing archaea (AOA), bacteria (AOB) and nitrite-oxidizing bacteria (NOB) to nitrification in four paddy soils from different geographic regions (Zi-Yang (ZY), Jiang-Du (JD), Lei-Zhou (LZ) and Jia-Xing (JX)) that are representative of the rice ecosystems in China. In urea-amended microcosms, nitrification activity varied greatly with 11.9, 9.46, 3.03 and 1.43 μg NO3−-N g−1 dry weight of soil per day in the ZY, JD, LZ and JX soils, respectively, over the course of a 56-day incubation period. Real-time quantitative PCR of amoA genes and pyrosequencing of 16S rRNA genes revealed significant increases in the AOA population to various extents, suggesting that their relative contributions to ammonia oxidation activity decreased from ZY to JD to LZ. The opposite trend was observed for AOB, and the JX soil stimulated only the AOB populations. DNA-based stable-isotope probing further demonstrated that active AOA numerically outcompeted their bacterial counterparts by 37.0-, 10.5- and 1.91-fold in 13C-DNA from ZY, JD and LZ soils, respectively, whereas AOB, but not AOA, were labeled in the JX soil during active nitrification. NOB were labeled to a much greater extent than AOA and AOB, and the addition of acetylene completely abolished the assimilation of 13CO2 by nitrifying populations. Phylogenetic analysis suggested that archaeal ammonia oxidation was predominantly catalyzed by soil fosmid 29i4-related AOA within the soil group 1.1b lineage. Nitrosospira cluster 3-like AOB performed most bacterial ammonia oxidation in the ZY, LZ and JX soils, whereas the majority of the 13C-AOB in the JD soil was affiliated with the Nitrosomona communis lineage. The 13C-NOB was overwhelmingly

  1. Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

    Science.gov (United States)

    Francis, Somilez Asya

    2014-01-01

    The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

  2. Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

    Science.gov (United States)

    Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

    Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  3. Formation of Hydroxylamine on Dust Grains via Ammonia Oxidation

    Science.gov (United States)

    He, Jiao; Vidali, Gianfranco; Lemaire, Jean-Louis; Garrod, Robin T.

    2015-01-01

    The quest to detect prebiotic molecules in space, notably amino acids, requires an understanding of the chemistry involving nitrogen atoms. Hydroxylamine (NH2OH) is considered a precursor to the amino acid glycine. Although not yet detected, NH2OH is considered a likely target of detection with ALMA. We report on an experimental investigation of the formation of hydroxylamine on an amorphous silicate surface via the oxidation of ammonia. The experimental data are then fed into a simulation of the formation of NH2OH in dense cloud conditions. On ices at 14 K and with a modest activation energy barrier, NH2OH is found to be formed with an abundance that never falls below a factor 10 with respect to NH3. Suggestions of conditions for future observations are provided.

  4. FORMATION OF HYDROXYLAMINE ON DUST GRAINS VIA AMMONIA OXIDATION

    Energy Technology Data Exchange (ETDEWEB)

    He, Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Lemaire, Jean-Louis [Paris Observatory, F-75014 Paris (France); Garrod, Robin T., E-mail: gvidali@syr.edu [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States)

    2015-01-20

    The quest to detect prebiotic molecules in space, notably amino acids, requires an understanding of the chemistry involving nitrogen atoms. Hydroxylamine (NH{sub 2}OH) is considered a precursor to the amino acid glycine. Although not yet detected, NH{sub 2}OH is considered a likely target of detection with ALMA. We report on an experimental investigation of the formation of hydroxylamine on an amorphous silicate surface via the oxidation of ammonia. The experimental data are then fed into a simulation of the formation of NH{sub 2}OH in dense cloud conditions. On ices at 14 K and with a modest activation energy barrier, NH{sub 2}OH is found to be formed with an abundance that never falls below a factor 10 with respect to NH{sub 3}. Suggestions of conditions for future observations are provided.

  5. Inhibition of Direct Electrolytic Ammonia Oxidation Due to a Change in Local pH

    International Nuclear Information System (INIS)

    Zöllig, Hanspeter; Morgenroth, Eberhard; Udert, Kai M.

    2015-01-01

    Electrochemical ammonia oxidation has gained a lot of attention recently as an efficient method for ammonia removal from wastewater, for the use in ammonia-based fuel cells and the production of high purity hydrogen. Thermally decomposed iridium oxide films (TDIROF) have been shown to be catalytically active for direct ammonia oxidation in aqueous solutions if NH 3 is present. However, the process was reported to be rapidly inhibited on TDIROF. Herein, we show that this fast inhibition of direct ammonia oxidation does not result from surface poisoning by adsorbed elemental nitrogen (N ads ). Instead, we propose that direct ammonia oxidation and oxygen evolution can lead to a drop of the local pH at the electrode resulting in a low availability of the actual reactant, NH 3 . The hypothesis was tested with cyclic voltammetry (CV) experiments on stagnant and rotating disk electrodes (RDE). The CV experiments on the stagnant electrode revealed that the decrease of the ammonia oxidation peaks was considerably reduced by introducing an idle phase at open circuit potential between subsequent scans. Furthermore, the polarization of the TDIROF electrode into the hydrogen evolution region (HER) resulted in increased ammonia oxidation peaks in the following anodic scans which can be explained with an increased local pH after the consumption of protons in the HER. On the RDE, the ammonia oxidation peaks did not decrease in immediately consecutive scans. These findings would not be expected if surface poisoning was responsible for the fast inhibition but they are in good agreement with the proposed mechanism of pH induced limitation by the reactant, NH 3 . The plausibility of the mechanism was also supported by our numerical simulations of the processes in the Nernstian diffusion layer. The knowledge about this inhibition mechanism of direct ammonia oxidation is especially important for the design of electrochemical cells for wastewater treatment. The mechanism is not only

  6. Shifts in the pelagic ammonia-oxidizing microbial communities along the eutrophic estuary of Yong River in Ningbo City, China

    NARCIS (Netherlands)

    Zhang, Qiufang; Tang, Fang-Yuan; Zhou, Yang-Jing; Xu, Jirong; Chen, Heping; Wang, Ming-Juang; Laanbroek, H.J.

    2015-01-01

    BACKGROUND: Aerobic ammonia oxidation plays a key role in the nitrogen cycle, and the diversity of the responsible microorganisms is regulated by environmental factors. Abundance and composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated in the surface

  7. [Ammonia-oxidizing archaea and their important roles in nitrogen biogeochemical cycling: a review].

    Science.gov (United States)

    Liu, Jing-Jing; Wu, Wei-Xiang; Ding, Ying; Shi, De-Zhi; Chen, Ying-Xu

    2010-08-01

    As the first step of nitrification, ammonia oxidation is the key process in global nitrogen biogeochemical cycling. So far, the autotrophic ammonia-oxidizing bacteria (AOB) in the beta- and gamma-subgroups of proteobacteria have been considered as the most important contributors to ammonia oxidation, but the recent researches indicated that ammonia-oxidizing archaea (AOA) are widely distributed in various kinds of ecosystems and quantitatively predominant, playing important roles in the global nitrogen biogeochemical cycling. This paper reviewed the morphological, physiological, and ecological characteristics and the molecular phylogenies of AOA, and compared and analyzed the differences and similarities of the ammonia monooxygenase (AMO) and its encoding genes between AOA and AOB. In addition, the potential significant roles of AOA in nitrogen biogeochemical cycling in aquatic and terrestrial ecosystems were summarized, and the future research directions of AOA in applied ecology and environmental protection were put forward.

  8. Denitrification rate determined by nitrate disapperance is higher than determined by nitrous oxide production with acetylene blockage

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    A mixed beech and spruce forest soil was incubated under potential denitrification assay (PDA) condition with 10% acetylene (C2H2) in the headspace of soil slurry bottles. Nitrous oxide (N2O) concentration in the headspace, as well as nitrate, nitrite and ammonium concentrations in the soil slurr...

  9. Short-term nitrous oxide profile dynamics and emissions response to water, nitrogen and carbon additions in two tropical soils

    Science.gov (United States)

    A. D. Nobre; M. Keller; P. M. Crill; R. C. Harriss

    2001-01-01

    Tropical soils are potentially the highest and least studied nitrous oxide (N2O) production areas in the world. The effect of water, nitrate and glucose additions on profile concentrations and episodic emissions of N2O for two volcanic soils in Costa Rica was examined. Magnitudes of episodic N2O pulses, as well as overall N2O emissions, varied considerably and...

  10. A two-step process of nitrous oxide before carbon dioxide for humanely euthanizing piglets: on-farm trials

    Science.gov (United States)

    The current methods of euthanizing neonatal piglets are raising concerns from the public and scientists. Our experiment tests the use of a two-step euthanasia method using nitrous oxide (N2O) for six minutes and then carbon dioxide (CO2) as a more humane way to euthanize piglets compared to just usi...

  11. From the Gut of an Insect to the Global Climate: Denitrification and Nitrous Oxide Production inside Lake Chironomidae

    DEFF Research Database (Denmark)

    Stief, Peter; Nielsen, Lars Peter; Revsbech, Niels Peter

    2006-01-01

    FROM THE GUT OF AN INSECT TO THE GLOBAL CLIMATE: DENITRIFICATION AND NITROUS OXIDE PRODUCTION INSIDE LAKE CHIRONOMIDAE P. Stief, L.P. Nielsen, N.P. Revsbech, A. Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Denitrifying bacteria in lake sediments drive...

  12. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of

  13. Source Tracking of Nitrous Oxide using A Quantum Cascade Laser System in the Field and Laboratory Environments

    Science.gov (United States)

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to...

  14. Effects of contrasting catch crops on nitrogen availability and nitrous oxide emissions in an organic cropping system

    DEFF Research Database (Denmark)

    Li, Xiaoxi; Petersen, Søren O; Sørensen, Peter

    2015-01-01

    Legume-based catch crops (LBCCs) may act as an important source of nitrogen (N) in organic crop rotations because of biological N fixation. However, the potential risk of high nitrous oxide (N2O) emissions needs to be taken into account when including LBCCs in crop rotations. Here, we report...

  15. DEVELOPMENT OF SAMPLING AND ANALYTICAL METHODS FOR THE MEASUREMENT OF NITROUS OXIDE FROM FOSSIL FUEL COMBUSTION SOURCES

    Science.gov (United States)

    The report documents the technical approach and results achieved while developing a grab sampling method and an automated, on-line gas chromatography method suitable to characterize nitrous oxide (N2O) emissions from fossil fuel combustion sources. The two methods developed have...

  16. Comparing the effects of cryotherapy with nitrous oxide gas versus topical corticosteroids in the treatment of oral lichen planus

    Directory of Open Access Journals (Sweden)

    Dariush Amanat

    2014-01-01

    Conclusion: Cryotherapy with nitrous oxide gas is as effective as topical triamcinolone acetonide in the treatment of OLP with no systemic side effects and needs less patient compliance. It can be considered as an alternative or adjuvant therapy in OLP patients to reduce the use of treatments with adverse effects.

  17. A comparison of myogenic motor evoked responses to electrical and magnetic transcranial stimulation during nitrous oxide/opioid anesthesia

    NARCIS (Netherlands)

    Ubags, L. H.; Kalkman, C. J.; Been, H. D.; Koelman, J. H.; Ongerboer de Visser, B. W.

    1999-01-01

    Transcranial motor evoked potentials (tc-MEPs) are used to monitor spinal cord integrity intraoperatively. We compared myogenic motor evoked responses with electrical and magnetic transcranial stimuli during nitrous oxide/opioid anesthesia. In 11 patients undergoing spinal surgery, anesthesia was

  18. Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

    Science.gov (United States)

    Debasish Saha; Benjamin M. Rau; Jason P. Kaye; Felipe Montes; Paul R. Adler; Armen R. Kemanian

    2016-01-01

    Future liquid fuel demand from renewable sources may, in part, be met by converting the seasonally wet portions of the landscape currently managed for soil and water conservation to perennial energy crops. However, this shift may increase nitrous oxide (N2O) emissions, thus limiting the carbon (C) benefits of energy crops. Particularly high emissions may occur during...

  19. Health Effects Associated With Exposure to Anesthetic Gas Nitrous Oxide-N2O in Clinical Hospital - Shtip Personel.

    Science.gov (United States)

    Eftimova, Bilijana; Sholjakova, Marija; Mirakovski, Dejan; Hadzi-Nikolova, Marija

    2017-10-15

    To show certain health effects associated with acute and chronic exposure to nitrous oxide of staff of the Department of Anaesthesiology and Intensive Care at the Clinical Hospital in Shtip. A transversal study was conducted, that include 43 health workers (23 - exposed and 20 - unexposed). Personal exposure to nitrous oxide for this group members was assessed through continuous measurement over 8 hours shift within breathing zone of the subjects involved, using handheld electrochemical instrument with datalogging option direct. In order to determine presence of possible health effects associated with acute and chronic exposure to nitrous oxide in ORs and ICUs, a specially designed questionnaire was prepared and distributed to be anonymously filled out, by all the examinees from both examined groups. Data were statistically tested for normality and also quantitative and qualitative assessment was performed. From the results obtained, a significant difference in several health effects between exposed and unexposed groups can be noted, including headaches, dizziness, nausea and vomiting, euphoria and tachycardia. Regarding the excitement, the appearance of depression, the feeling of numbness and tingling of the hands and feet, the differences between the two examined groups were not significant. It can be concluded that chronic exposure to nitrous oxide is associated with the adverse health effects.

  20. Update of emission factors for nitrous oxide from agricultural soils on the basis of measurements in the Netherlands

    NARCIS (Netherlands)

    Kuikman, P.J.; Hoek, van der K.W.; Smit, A.; Zwart, K.B.

    2006-01-01

    Emissions of nitrous oxide (N2O) in the Netherlands are reported to the UNFCCC on the basis of a country specific methodology. In this study we have identified and analysed the values for emission factors in measurement from in the Netherlands in the period 1993 – 2003. The overall averaged emission

  1. First results of tall tower based nitrous oxide flux monitoring over an agricultural region in Central Europe

    Science.gov (United States)

    Haszpra, László; Hidy, Dóra; Taligás, Tímea; Barcza, Zoltán

    2018-03-01

    Nitrous oxide is one of the atmospheric greenhouse gases whose amount is significantly influenced by human activity. Its major anthropogenic sources are the agricultural soils but the emission is known only with large uncertainty yet. The paper presents a tall tower based measuring system installed in Hungary, which is designed for the long-term monitoring of nitrous oxide emission of a regionally typical composition of agricultural fields by means of eddy covariance technique. Due to the careful calibration of the gas analyzer applied the measuring system is also suitable for the recording of the atmospheric concentration of nitrous oxide on the globally compatible scale (WMO X2006A). The paper reports the results of the first two years of the monitoring program, which is the first of its kind in Central Europe. For the period of July 2015-June 2017 the concentration measurements indicate an increasing trend of 0.91 nmol mol-1 year-1 with an average concentration of 330.64 nmol mol-1. During the two years of the project, the monitoring system recorded a total of 441 ± 195 mg N2O-N m-2 nitrous oxide emission with late spring/early summer maximum. The measurements also revealed the episodic nature of the emission typically triggered by major precipitation events.

  2. Spring-Thaw Nitrous Oxide Emissions from Reed Canarygrass on Wetness-Prone Marginal Soil in New York State

    NARCIS (Netherlands)

    Mason, C.; Stoof, C.R.; Richards, B.K.; Rossiter, D.; Steenhuis, T.S.

    2016-01-01

    In temperate climates, a significant fraction of annual emissions of nitrous oxide (N2O) from agricultural land can occur during soil thaw in late winter and early spring. The objective of this study is to determine the impact of land use change from long-term fallow grassland to managed perennial

  3. Simulation of nitrous oxide effluxes, crop yields and soil physical properties using the LandscapeDNDC model in managed ecosystem

    Science.gov (United States)

    Nyckowiak, Jedrzej; Lesny, Jacek; Haas, Edwin; Juszczak, Radoslaw; Kiese, Ralf; Butterbach-Bahl, Klaus; Olejnik, Janusz

    2014-05-01

    Modeling of nitrous oxide emissions from soil is very complex. Many different biological and chemical processes take place in soils which determine the amount of emitted nitrous oxide. Additionaly, biogeochemical models contain many detailed factors which may determine fluxes and other simulated variables. We used the LandscapeDNDC model in order to simulate N2O emissions, crop yields and soil physical properties from mineral cultivated soils in Poland. Nitrous oxide emissions from soils were modeled for fields with winter wheat, winter rye, spring barley, triticale, potatoes and alfalfa crops. Simulations were carried out for the plots of the Brody arable experimental station of Poznan University of Life Science in western Poland and covered the period 2003 - 2012. The model accuracy and its efficiency was determined by comparing simulations result with measurements of nitrous oxide emissions (measured with static chambers) from about 40 field campaigns. N2O emissions are strongly dependent on temperature and soil water content, hence we compared also simulated soil temperature at 10cm depth and soil water content at the same depth with the daily measured values of these driving variables. We compared also simulated yield quantities for each individual experimental plots with yield quantities which were measured in the period 2003-2012. We conclude that the LandscapeDNDC model is capable to simulate soil N2O emissions, crop yields and physical properties of soil with satisfactorily good accuracy and efficiency.

  4. Mitigation of methane and nitrous oxide emissions from animal operations: II. A review of manure management mitigation options

    NARCIS (Netherlands)

    Montes, F.; Meinen, R.; Dell, C.; Rotz, A.; Hristov, A.N.; Oh, J.; Waghorn, G.; Gerber, P.J.; Henderson, B.L.; Makkar, H.P.S.; Dijkstra, J.

    2013-01-01

    This review analyzes published data on manure management practices used to mitigate methane (CH4) and nitrous oxide (N2O) emissions from animal operations. Reducing excreted nitrogen (N) and degradable organic carbon (C) by diet manipulation to improve the balance of nutrient inputs with production

  5. MLS/Aura Near-Real-Time L2 Nitrous Oxide (N2O) Mixing Ratio V003

    Data.gov (United States)

    National Aeronautics and Space Administration — ML2N2O_NRT is the EOS Aura Microwave Limb Sounder (MLS) Near-Real-Time (NRT) product for nitrous oxide (N2O). This product contains daily N2O profiles taken from the...

  6. Characteristic of nitrous oxide production in partial denitrification process with high nitrite accumulation.

    Science.gov (United States)

    Du, Rui; Peng, Yongzhen; Cao, Shenbin; Wang, Shuying; Niu, Meng

    2016-03-01

    Nitrous oxide (N2O) production during the partial denitrification process with nitrate (NO3(-)-N) to nitrite (NO2(-)-N) transformation ratio of 80% was investigated in this study. Results showed that N2O was seldom observed before complete depletion of NO3(-)-N, but it was closely related to the reduction of NO2(-)-N rather than NO3(-)-N. High COD/NO3(-)-N was in favor of N2O production in partial denitrification with high NO2(-)-N accumulation. It was seriously enhanced at constant acidic pH due to the free nitrous acid (FNA) inhibition. However, the N2O production was much lower at initial pH of 5.5 and 6.5 due to the pH increase during denitrification process. Significantly, the pH turning point could be chosen as a controlled parameter to denote the end of NO3(-)-N reduction, which could not only achieve high NO2(-)-N accumulation but also decrease the N2O production significantly for practical application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Assessment of nitric oxide (NO) redox reactions contribution to nitrous oxide (N2 O) formation during nitrification using a multispecies metabolic network model.

    Science.gov (United States)

    Perez-Garcia, Octavio; Chandran, Kartik; Villas-Boas, Silas G; Singhal, Naresh

    2016-05-01

    Over the coming decades nitrous oxide (N2O) is expected to become a dominant greenhouse gas and atmospheric ozone depleting substance. In wastewater treatment systems, N2O is majorly produced by nitrifying microbes through biochemical reduction of nitrite (NO2(-)) and nitric oxide (NO). However it is unknown if the amount of N2O formed is affected by alternative NO redox reactions catalyzed by oxidative nitrite oxidoreductase (NirK), cytochromes (i.e., P460 [CytP460] and 554 [Cyt554 ]) and flavohemoglobins (Hmp) in ammonia- and nitrite-oxidizing bacteria (AOB and NOB, respectively). In this study, a mathematical model is developed to assess how N2O formation is affected by such alternative nitrogen redox transformations. The developed multispecies metabolic network model captures the nitrogen respiratory pathways inferred from genomes of eight AOB and NOB species. The performance of model variants, obtained as different combinations of active NO redox reactions, was assessed against nine experimental datasets for nitrifying cultures producing N2O at different concentration of electron donor and acceptor. Model predicted metabolic fluxes show that only variants that included NO oxidation to NO2(-) by CytP460 and Hmp in AOB gave statistically similar estimates to observed production rates of N2O, NO, NO2(-) and nitrate (NO3(-)), together with fractions of AOB and NOB species in biomass. Simulations showed that NO oxidation to NO2(-) decreased N2O formation by 60% without changing culture's NO2(-) production rate. Model variants including NO reduction to N2O by Cyt554 and cNor in NOB did not improve the accuracy of experimental datasets estimates, suggesting null N2O production by NOB during nitrification. Finally, the analysis shows that in nitrifying cultures transitioning from dissolved oxygen levels above 3.8 ± 0.38 to <1.5 ± 0.8 mg/L, NOB cells can oxidize the NO produced by AOB through reactions catalyzed by oxidative NirK. © 2015 Wiley Periodicals, Inc.

  8. Anodic ammonia oxidation to nitrogen gas catalyzed by mixed biofilms in bioelectrochemical systems

    International Nuclear Information System (INIS)

    Zhan, Guoqiang; Zhang, Lixia; Tao, Yong; Wang, Yujian; Zhu, Xiaoyu; Li, Daping

    2014-01-01

    In this paper we report ammonia oxidation to nitrogen gas using microbes as biocatalyst on the anode, with polarized electrode (+600 mV vs. Ag/AgCl) as electron acceptor. In batch experiments, the maximal rate of ammonia-N oxidation by the mixed culture was ∼ 60 mg L −1 d −1 , and nitrogen gas was the main products in anode compartment. Cyclic voltammetry for testing the electroactivity of the anodic biofilms revealed that an oxidation peak appeared at +600 mV (vs. Ag/AgCl), whereas the electrode without biofilms didn’t appear oxidation peak, indicating that the bioanode had good electroactivities for ammonia oxidation. Microbial community analysis of 16S rRNA genes based on high throughput sequencing indicated that the combination of the dominant genera of Nitrosomonas, Comamonas and Paracocus could be important for the electron transfer from ammonia oxidation to anode

  9. Direct and indirect nitrous oxide emissions from agricultural soils, 1990 - 2003. Background document on the calculation method for the Dutch National Inventory Report

    NARCIS (Netherlands)

    Hoek KW van der; Schijndel MW van; Kuikman PJ; MNP; Alterra; LVM

    2007-01-01

    Since 2005 the Dutch method to calculate the nitrous oxide emissions from agricultural soils has fully complied with the Intergovernmental Panel on Climate Change (IPCC) Good Practice Guidelines. In order to meet the commitments of the Convention on Climate Change and the Kyoto Protocol, nitrous

  10. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    Energy Technology Data Exchange (ETDEWEB)

    Musenze, Ronald S.; Werner, Ursula [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); Grinham, Alistair [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); School of Civil Engineering, the University of Queensland, Brisbane, Qld 4072 (Australia); Udy, James [Healthy Waterways Ltd, P.O. Box 13086, George Street, Brisbane, Qld 4003 (Australia); Yuan, Zhiguo, E-mail: z.yuan@awmc.uq.edu.au [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia)

    2014-02-01

    Methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH{sub 4} and N{sub 2}O all-year-round. Dissolved N{sub 2}O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH{sub 4} concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH{sub 4} and N{sub 2}O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N{sub 2}O saturation significantly increased with NO{sub x} concentrations (r{sup 2} = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N{sub 2}O m{sup −2} d{sup −1} and 0.3 to 27.9 mg CH{sub 4} m{sup −2} d{sup −1}. Total emissions (CO{sub 2}-e) were N{sub 2}O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that

  11. Methane and Nitrous Oxide Emissions from Agriculture on a Regional Scale

    Directory of Open Access Journals (Sweden)

    Agnieszka Wysocka-Czubaszek

    2018-05-01

    Full Text Available Nowadays, agriculture has to meet the growing food demand together with high requirements of environmental protection, especially regarding the climate change. The greenhouse gas emissions differ not only on a global, but also on a regional scale, and mitigation strategies are effective when they are adapted properly. Therefore, the aim of this paper is to present the results of methane (CH4 and nitrous oxide (N2O emissions inventory on a regional level in Poland in years 1999-2015. The CH4 and N2O emissions were calculated according to the methodology used by the National Centre for Emissions Management (NCEM for national inventory for United Nations Framework Convention on Climate Change and Kyoto Protocol. The data were taken from Central Statistical Office of Poland. The CH4 emissions in all studied years varied strongly between voivodeships and ranged from 5.6-7.5 Gg y-1 in the Lubuskie Voivodeship to 84.8-104.3 Gg y-1 in the Mazowieckie Voivodeship. While in most voivodeships the CH4 emissions dropped down, in Podlaskie, Mazursko-Warmińskie, and Wielkopolskie voivodeships, the emissions of this gas increased significantly as a consequence of the development of dairy and meat production. In 1999, the highest N2O fluxes were calculated for the Wielkopolskie (5.7 Gg y-1, Mazowieckie (4.8 Gg y-1 Kujawsko-Pomorskie (3.5 Gg y-1 and Lubelskie (3.3 Gg y-1 voivodeships, while in 2015, the highest nitrous oxide emissions were calculated for the Wielkopolskie (7.3 Gg y-1, Mazowieckie (5.5 Gg y-1, Kujawsko-Pomorskie (4.1 Gg y-1 and Podlaskie (4.1 Gg y-1 voivodeships. In the studied period, the contribution of N2O emissions from crop production increased in almost all voivodeships except the Podlaskie, Lubuskie and Warmińsko-Mazurskie regions. The growth in emissions from mineral fertilization and crop residue incorporation, together with the increase of emission from the animal sector in some regions of Poland, resulted in the higher national

  12. Direct Nitrous Oxide Emission from the Aquacultured Pacific White Shrimp (Litopenaeus vannamei).

    Science.gov (United States)

    Heisterkamp, Ines M; Schramm, Andreas; de Beer, Dirk; Stief, Peter

    2016-07-01

    The Pacific white shrimp (Litopenaeus vannamei) is widely used in aquaculture, where it is reared at high stocking densities, temperatures, and nutrient concentrations. Here we report that adult L. vannamei shrimp emit the greenhouse gas nitrous oxide (N2O) at an average rate of 4.3 nmol N2O/individual × h, which is 1 to 2 orders of magnitude higher than previously measured N2O emission rates for free-living aquatic invertebrates. Dissection, incubation, and inhibitor experiments with specimens from a shrimp farm in Germany indicated that N2O is mainly produced in the animal's gut by microbial denitrification. Microsensor measurements demonstrated that the gut interior is anoxic and nearly neutral and thus is favorable for denitrification by ingested bacteria. Dinitrogen (N2) and N2O accounted for 64% and 36%, respectively, of the nitrogen gas flux from the gut, suggesting that the gut passage is too fast for complete denitrification to be fully established. Indeed, shifting the rearing water bacterial community, a diet component of shrimp, from oxic to anoxic conditions induced N2O accumulation that outlasted the gut passage time. Shrimp-associated N2O production was estimated to account for 6.5% of total N2O production in the shrimp farm studied here and to contribute to the very high N2O supersaturation measured in the rearing tanks (2,099%). Microbial N2O production directly associated with aquacultured animals should be implemented into life cycle assessments of seafood production. The most widely used shrimp species in global aquaculture, Litopenaeus vannamei, is shown to emit the potent greenhouse gas nitrous oxide (N2O) at a particularly high rate. Detailed experiments reveal that N2O is produced in the oxygen-depleted gut of the animal by bacteria that are part of the shrimp diet. Upon ingestion, these bacteria experience a shift from oxic to anoxic conditions and therefore switch their metabolism to the anaerobic denitrification process, which produces N

  13. Designing bioenergy crop buffers to mitigate nitrous oxide emissions and water quality impacts from agriculture

    Science.gov (United States)

    Gopalakrishnan, G.; Negri, C. M.

    2010-12-01

    There is a strong societal need to evaluate and understand the environmental aspects of bioenergy production, especially due to the significant increases in production mandated by many countries, including the United States. Bioenergy is a land-based renewable resource and increases in production are likely to result in large-scale conversion of land from current uses to bioenergy crop production; potentially causing increases in the prices of food, land and agricultural commodities as well as disruption of ecosystems. Current research on the environmental sustainability of bioenergy has largely focused on the potential of bioenergy crops to sequester carbon and mitigate greenhouse gas (GHG) emissions and possible impacts on water quality and quantity. A key assumption in these studies is that bioenergy crops will be grown in a manner similar to current agricultural crops such as corn and hence would affect the environment similarly. This study presents a systems approach where the agricultural, energy and environmental sectors are considered as components of a single system, and bioenergy crops are used to design multi-functional agricultural landscapes that meet society’s requirements for food, energy and environmental protection. We evaluate the production of bioenergy crop buffers on marginal land and using degraded water and discuss the potential for growing cellulosic bioenergy crops such as miscanthus and switchgrass in optimized systems such that (1) marginal land is brought into productive use; (2) impaired water is used to boost yields (3); clean freshwater is left for other uses that require higher water quality; and (4) feedstock diversification is achieved that helps ecological sustainability, biodiversity, and economic opportunities for farmers. The process-based biogeochemical model DNDC was used to simulate crop yield, nitrous oxide production and nitrate concentrations in groundwater when bioenergy crops were grown in buffer strips adjacent to

  14. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    International Nuclear Information System (INIS)

    Musenze, Ronald S.; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2014-01-01

    Methane (CH 4 ) and nitrous oxide (N 2 O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH 4 and N 2 O all-year-round. Dissolved N 2 O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH 4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH 4 and N 2 O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N 2 O saturation significantly increased with NO x concentrations (r 2 = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N 2 O m −2 d −1 and 0.3 to 27.9 mg CH 4 m −2 d −1 . Total emissions (CO 2 -e) were N 2 O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that in tropical rivers and polluted estuaries. • Emissions are dominated by N2O, which

  15. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Regina, K.

    1998-12-31

    Soils are an important source of nitrous oxide (N{sub 2}O) and nitric oxide (NO). N{sub 2}O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N{sub 2}O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N{sub 2}O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N{sub 2}O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N{sub 2}O flux rates. The importance of the water table in regulating N{sub 2}0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N{sub 2}0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N{sub 2}O. Nutrient-rich peatlands had much higher capacities for N{sub 2}O and NO production than poorer ones. The addition of KNO{sub 3}, NH{sub 4}Cl or urea to minerotrophic peat further increased the fluxes of N{sub 2}O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N{sub 2}0 and NO and nitrification activity measured as the numbers of nitrite

  16. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    International Nuclear Information System (INIS)

    Regina, K.

    1998-01-01

    Soils are an important source of nitrous oxide (N 2 O) and nitric oxide (NO). N 2 O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N 2 O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N 2 O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N 2 O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N 2 O flux rates. The importance of the water table in regulating N 2 0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N 2 0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N 2 O. Nutrient-rich peatlands had much higher capacities for N 2 O and NO production than poorer ones. The addition of KNO 3 , NH 4 Cl or urea to minerotrophic peat further increased the fluxes of N 2 O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N 2 0 and NO and nitrification activity measured as the numbers of nitrite-oxidising bacteria, nitrification potential or in situ net

  17. Microbial production of nitrous oxide and nitric oxide in boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Regina, K

    1999-12-31

    Soils are an important source of nitrous oxide (N{sub 2}O) and nitric oxide (NO). N{sub 2}O is a greenhouse gas participating in both warming of the climate and the destruction of ozone, and NO is active in tropospheric chemistry. The fluxes and formation mechanisms of these gases in boreal Finnish peatlands were studied by both laboratory and field techniques. Special attention was paid to factors regulating their production, e.g. height of the water table, pH, temperature, nutrient level and nitrification activity. Both N{sub 2}O and NO fluxes were detected in the peatlands, some of which were sources of these trace gases and some sinks. The flux rates of N{sub 2}O ranged from negative values to several milligrammes per square metre per day. Natural peatlands were the lowest sources of N{sub 2}O, often showing negative fluxes, whereas sites drained for forestry some decades ago had markedly higher fluxes. A site drained for agriculture (grassland) was the highest source found. NO fluxes were observed on the two drained sites studied, a forested fen and the same field of grass, but not on a natural fen with a high water table. NO fluxes amounted to 16-30 % of the N{sub 2}O flux rates. The importance of the water table in regulating N{sub 2}0 fluxes was demonstrated in field and laboratory studies. It was shown in the laboratory that even a short lowering of the water table, for 14 weeks at 20 deg C, induced N{sub 2}0 fluxes from the fens that normally acted as sinks or only low sources. Raising the water table in peat monoliths from drained sites reduced the flux of N{sub 2}O. Nutrient-rich peatlands had much higher capacities for N{sub 2}O and NO production than poorer ones. The addition of KNO{sub 3}, NH{sub 4}Cl or urea to minerotrophic peat further increased the fluxes of N{sub 2}O and NO, and also nitrogen mineralisation. There was a clear connection between the fluxes of N{sub 2}0 and NO and nitrification activity measured as the numbers of nitrite

  18. Optimum time for intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide in children without any premedication.

    Science.gov (United States)

    Hasan, Abm Kamrul; Sivasankar, Raman; Nair, Salil G; Hasan, Wamia U; Latif, Zulaidi

    2018-02-01

    Intravenous cannulation is usually done in children after inhalational induction with volatile anesthetic agents. The optimum time for safe intravenous cannulation after induction with sevoflurane, oxygen, and nitrous oxide has been studied in premedicated children, but there is no information for the optimum time for cannulation with inhalational induction in children without premedication. The aim of this study was to determine the optimum time for intravenous cannulation after the induction of anesthesia with sevoflurane, oxygen, and nitrous oxide in children without any premedication. This is a prospective, observer-blinded, up-and-down sequential allocation study in unpremedicated ASA grade 1 children aged 2-6 years undergoing elective dental surgery. Intravenous cannulation was attempted after inhalational induction with sevoflurane, oxygen, and nitrous oxide. The timing of cannulation was considered adequate if there was no movement, coughing, or laryngospasm. The cannulation attempt for the first child was set at 4 minutes after the loss of eyelash reflex and the time for intravenous cannulation was determined by the up-and-down method using 15 seconds as step size. Probit test was used to analyze the up-down sequences for the study. The adequate time for effective cannulation after induction with sevoflurane, oxygen, and nitrous oxide in 50% and 95% of patients was 53.02 seconds (95% confidence limits, 20.23-67.76 seconds) and 87.21 seconds (95% confidence limits, 70.77-248.03 seconds), respectively. We recommend waiting for 1 minute 45 seconds (105 seconds) after the loss of eyelash reflex before attempting intravenous cannulation in pediatric patients induced with sevoflurane, oxygen, and nitrous oxide without any premedication. © 2018 John Wiley & Sons Ltd.

  19. Steady-State Growth under Inorganic Carbon Limitation Conditions Increases Energy Consumption for Maintenance and Enhances Nitrous Oxide Production in Nitrosomonas europaea.

    Science.gov (United States)

    Mellbye, Brett L; Giguere, Andrew; Chaplen, Frank; Bottomley, Peter J; Sayavedra-Soto, Luis A

    2016-06-01

    Nitrosomonas europaea is a chemolithoautotrophic bacterium that oxidizes ammonia (NH3) to obtain energy for growth on carbon dioxide (CO2) and can also produce nitrous oxide (N2O), a greenhouse gas. We interrogated the growth, physiological, and transcriptome responses of N. europaea to conditions of replete (>5.2 mM) and limited inorganic carbon (IC) provided by either 1.0 mM or 0.2 mM sodium carbonate (Na2CO3) supplemented with atmospheric CO2 IC-limited cultures oxidized 25 to 58% of available NH3 to nitrite, depending on the dilution rate and Na2CO3 concentration. IC limitation resulted in a 2.3-fold increase in cellular maintenance energy requirements compared to those for NH3-limited cultures. Rates of N2O production increased 2.5- and 6.3-fold under the two IC-limited conditions, increasing the percentage of oxidized NH3-N that was transformed to N2O-N from 0.5% (replete) up to 4.4% (0.2 mM Na2CO3). Transcriptome analysis showed differential expression (P ≤ 0.05) of 488 genes (20% of inventory) between replete and IC-limited conditions, but few differences were detected between the two IC-limiting treatments. IC-limited conditions resulted in a decreased expression of ammonium/ammonia transporter and ammonia monooxygenase subunits and increased the expression of genes involved in C1 metabolism, including the genes for RuBisCO (cbb gene cluster), carbonic anhydrase, folate-linked metabolism of C1 moieties, and putative C salvage due to oxygenase activity of RuBisCO. Increased expression of nitrite reductase (gene cluster NE0924 to NE0927) correlated with increased production of N2O. Together, these data suggest that N. europaea adapts physiologically during IC-limited steady-state growth, which leads to the uncoupling of NH3 oxidation from growth and increased N2O production. Nitrification, the aerobic oxidation of ammonia to nitrate via nitrite, is an important process in the global nitrogen cycle. This process is generally dependent on ammonia-oxidizing

  20. Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions in nitric and perchloric acid solutions

    International Nuclear Information System (INIS)

    Nikitenko, S.I.; Astafurova, L.N.

    1991-01-01

    Kinetics of uranium (4) oxidation with nitrous acid in the presence of oxalate-ions are studied spectrometrically. It is shown that even at small oxalate concentrations a notable effect of tetravalent uranium stabilization is observed relatively to the oxidation with nitrous acid. In case of a significant excess of oxalate-ions the oxidation rate will be considerably slower as a result of the formation of U(4) bisoxalate complex

  1. Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution.

    Science.gov (United States)

    Hung, Chang-Mao

    2009-07-30

    Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h(-1).

  2. Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Chang-Mao, E-mail: hungcm1031@gmail.com [Department of Industry Engineering and Management, Yung-Ta Institute of Technology and Commerce, 316 Chung-shan Road, Linlo, Pingtung 909, Taiwan (China)

    2009-07-30

    Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h{sup -1}.

  3. Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

    International Nuclear Information System (INIS)

    Hung, Chang-Mao

    2009-01-01

    Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h -1 .

  4. A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

    Directory of Open Access Journals (Sweden)

    Chyan-Chyi Wu

    2011-11-01

    Full Text Available A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 mm complementary metal oxide semiconductor (CMOS process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

  5. [Nitrous oxide production by the German Armed Forces in the 20th century : History of medicine and pharmacy in the Armed Forces].

    Science.gov (United States)

    Kronabel, D B J

    2010-03-01

    The nitrous oxide production unit of the German Armed Forces was a worldwide unique facility which was only employed in the former main medical depot at Euskirchen (nitrous oxide: medical gas which is now obsolete). The last unit was phased out in 2002 and brought to the main medical depot at Blankenburg. Unfortunately the unit is now no longer in the depot and seems to have disappeared. This article describes the nitrous oxide production process and the use of the production unit which was designed by the Socsil company of Switzerland.

  6. Plant-wide modelling and control of nitrous oxide emissions from wastewater treatment plants

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo

    Nitrous oxide (N2O) is a greenhouses gas with a global warming potential three hundred times stronger than carbon dioxide (CO2). The IPCC report released in 2014 shows that the CO2 equivalents emitted from the wastewater systems are increasing in the last decades. It was also estimated that 14......% of those CO2 equivalents comes from N2O emissions. It becomes therefore relevant, within the context of reducing the carbon footprint of wastewater treatment (WWT) systems, to develop control strategies aimed at the minimization of the emissions of this gas. Till now, few operation strategies have been....... To avoid poor performance behaviour due to intuitive design, a systematic procedure for the design of fuzzy-logic controllers is developed using a partial nitritation/Anammox system as application case. The same systematic methodology is then adopted to tune the fuzzy-logic controller for low N2O emissions...

  7. Effects of nitrous oxide on cerebral haemodynamics and metabolism during isoflurane anaesthesia in man

    International Nuclear Information System (INIS)

    Algotsson, L.; Messeter, K.; Rosen, I.; Holmin. T.

    1992-01-01

    Seven normoventilated and five hyperventilated healthy adults undergoing cholecystectomy and anaesthetized with methohexitone, fentanyl and pancuronium were studied with measurement of cerebral blood flow (CBF), cereal metabolic rate of oxygen (CMRo 2 ), and quantified electroencephalography (EEG) under two sets of conditions: 1) 1.7% end-tidal concentration of isoflurane in air/oxygen: 2) 0.85% end-tidal concentration of isoflurane in nitrous oxide (N 2 O)/oxygen. The object was to study the effects of N 2 O during isoflurane anaesthesia on cerebral circulation, metabolism and neuroelectric activity. N 2 O in the anaesthetic gas mixture caused a 43% (P 2 was not significantly altered by N 2 O. EEG demonstrated an activated pattern with decreased low frequency activity and increased high frequency activity. The results confirm that N 2 O is a potent cerebral vasodilator in man, although the mechanisms underlying the effects on CBF are still unclear. (au)

  8. Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology - A critical review.

    Science.gov (United States)

    Duan, Haoran; Ye, Liu; Erler, Dirk; Ni, Bing-Jie; Yuan, Zhiguo

    2017-10-01

    Nitrous oxide (N 2 O) is an important greenhouse gas and an ozone-depleting substance which can be emitted from wastewater treatment systems (WWTS) causing significant environmental impacts. Understanding the N 2 O production pathways and their contribution to total emissions is the key to effective mitigation. Isotope technology is a promising method that has been applied to WWTS for quantifying the N 2 O production pathways. Within the scope of WWTS, this article reviews the current status of different isotope approaches, including both natural abundance and labelled isotope approaches, to N 2 O production pathways quantification. It identifies the limitations and potential problems with these approaches, as well as improvement opportunities. We conclude that, while the capabilities of isotope technology have been largely recognized, the quantification of N 2 O production pathways with isotope technology in WWTS require further improvement, particularly in relation to its accuracy and reliability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Quantum cascade laser photoacoustic detection of nitrous oxide released from soils for biofuel production

    Science.gov (United States)

    Couto, F. M.; Sthel, M. S.; Castro, M. P. P.; da Silva, M. G.; Rocha, M. V.; Tavares, J. R.; Veiga, C. F. M.; Vargas, H.

    2014-12-01

    In order to investigate the generation of greenhouse gases in sugarcane ethanol production chain, a comparative study of N2O emission in artificially fertilized soils and soils free from fertilizers was carried out. Photoacoustic spectroscopy using quantum cascade laser with an emission ranging from 7.71 to 7.88 µm and differential photoacoustic cell were applied to detect nitrous oxide (N2O), an important greenhouse gas emitted from soils cultivated with sugar cane. Owing to calibrate the experimental setup, an initial N2O concentration was diluted with pure nitrogen and detection limit of 50 ppbv was achieved. The proposed methodology was selective and sensitive enough to detect N2O from no fertilized and artificially fertilized soils. The measured N2O concentration ranged from ppmv to ppbv.

  10. Soil nitrous oxide and methane fluxes in integrated crop-livestock systems in subtropics

    International Nuclear Information System (INIS)

    Dieckow, Jeferson; Pergher, Maico; Moraes, Anibal de; Piva, Jonatas Thiago; Bayer, Cimélio; Sakadevan, Karuppan

    2015-01-01

    Integrated crop-livestock (ICL) system is an agricultural practice in which crop-pasture rotation is carried out in the same field over time. In Brasil, ICL associated with no-tillage farming is increasingly gaining importance as a soil use strategy that improves food production (grain, milk and beef) and economic returns to farmers. Integrated crop-livestock-forestry (ICLF) is a recent modification of ICL in Brazil, with the inclusion of trees cultivation aiming at additional wood production and offering thermal comfort to livestock (Porfírio-da-Silva & Moraes, 2010). However, despite the increasing importance of ICL, little information is available on how this system may affect soil-atmosphere exchange of nitrous oxide (N 2 O) and methane (CH 4 )

  11. [Contribution of fungi to soil nitrous oxide emission and their research methods: a review].

    Science.gov (United States)

    Huang, Ying; Long, Xi-En

    2014-04-01

    Nitrous oxide is an important greenhouse gas. Soil is one major emission source of N2O, which is a by-product of microorganisms-driven nitrification and denitrification processes. Extensive research has demonstrated archaea and bacteria are the predominant contributors in nitrification and denitrification. However, fungi may play a predominant role in the N transformation in a certain soil ecosystem. The fungal contribution to N2O production has been rarely investigated. Here, we reviewed the mechanism of N2O production by soil fungi. The mechanisms of denitrification, autotrophic and heterotrophic nitrification and their key microbes and functional genes were described, respectively. We discriminated the differences in denitrification between bacteria and fungi and discussed the methods being used to determine the contribution of fungi to soil N2O emission, including selective inhibitors, 15N stable isotope probing, isolation and pure culturing and uncultured molecular detection methods. The existing problems and research prospects were also presented.

  12. Hemodynamics and Gas Exchange Effects of Inhaled Nitrous Oxide in Patients with Acute Respiratory Distress Syndrome

    Directory of Open Access Journals (Sweden)

    V. N. Poptsov

    2006-01-01

    Full Text Available Inhaled nitrous oxide (iNO therapy aimed at improving pulmonary oxygenizing function and at decreasing artificial ventilation (AV load has been used in foreign clinical practice in the past decade. The study was undertaken to evaluate the hemodynamic and gas exchange effects of iNO in acute respiratory distress syndrome (ARDS that developed after car-diosurgical operations. Fifty-eight (43 males and 15 females patients aged 21 to 76 (55.2±2.4 years were examined. The study has demonstrated that in 48.3% of cases, the early stage of ARDS is attended by the increased tone pulmonary vessels due to impaired NO-dependent vasodilatation. In these patients, iNO therapy is an effective therapeutic method for correcting hemodynamic disorders and lung oxygenizing function.

  13. On the Pt(+) and Rh(+) Catalytic Activity in the Nitrous Oxide Reduction by Carbon Monoxide.

    Science.gov (United States)

    Rondinelli, F; Russo, N; Toscano, M

    2008-11-11

    Nitrous oxide activation by CO in the presence of platinum and rhodium monocations was elucidated by density functional methods for ground and first excited states. Platinum and rhodium cations fulfill the thermodynamic request for the oxygen-atom transport that allows the catalytic cycle to be completed, but actually, just the first one meaningfully improves the kinetics of the process. For both catalysts, the reaction pathways show the only activation barrier in correspondence of nitrogen release and monoxide cation formation. The kinetic analysis of the potential energy profile, in agreement with ICP/SIFT MS experimental data, indicates that platinum performs more in the reduction, while the whole process is not sufficiently fast in the case of rhodium ionic catalyst.

  14. Establishment and calibration of consensus process model for nitrous oxide dynamics in water quality engineering

    DEFF Research Database (Denmark)

    Domingo-Felez, Carlos

    that enhance cost and energy efficiency in BNR, while maintaining effluent quali-ty. Now, increasing attention is placed on direct emissions of nitrous oxide (N2O) as by-product of BNR; N2O is a greenhouse gas (GHG) with a high warming potential and also an ozone depleting chemical compound. Several N2O...... process modelling efforts aim to reproduce ex-perimental data with mathematical equations, structuring our understanding of the system. Various mechanistic models with different structures describ-ing N2O production have been proposed, but no consensus exists between researchers. Hence, the existing plant......-wide GHG models still lack a complete biological process model that can be integrated in a methodology that assess-es N2O emissions and their impact on overall plant performance. A mathematical model structure that describes N2O production during biological nitrogen removal is proposed. Two autotrophic...

  15. Ab initio intermolecular potential energy surface and thermophysical properties of nitrous oxide.

    Science.gov (United States)

    Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

    2015-06-28

    We present an analytical intermolecular potential energy surface (PES) for two rigid nitrous oxide (N2O) molecules derived from high-level quantum-chemical ab initio calculations. Interaction energies for 2018 N2O-N2O configurations were computed utilizing the counterpoise-corrected supermolecular approach at the CCSD(T) level of theory using basis sets up to aug-cc-pVQZ supplemented with bond functions. A site-site potential function with seven sites per N2O molecule was fitted to the pair interaction energies. We validated our PES by computing the second virial coefficient as well as shear viscosity and thermal conductivity in the dilute-gas limit. The values of these properties are substantiated by the best experimental data.

  16. The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms

    Science.gov (United States)

    Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

    2013-10-01

    Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 μg N2O m-2 d-1, and improved nitrate removal (P 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

  17. Ammonium sorption and ammonia inhibition of nitrite-oxidizing bacteria explain contrasting soil N2O production

    Science.gov (United States)

    Venterea, R. T.; Sadowsky, M.; Breuillin-Sessoms, F.; Wang, P.; Clough, T. J.; Coulter, J. A.

    2015-12-01

    Better understanding of process controls over nitrous oxide (N2O) production in urine-impacted 'hot spots' and fertilizer bands is needed to improve mitigation strategies and emission models. Following amendment with bovine (Bos taurus) urine (Bu) or urea (Ur), we measured inorganic N, pH, N2O, and genes associated with nitrification in two soils ('L' and 'W') having similar texture, pH, C, and C/N ratio. Solution-phase ammonia (slNH3) was also calculated accounting for non-linear ammonium (NH4+) sorption capacities (ASC). Soil W displayed greater nitrification rates and nitrate (NO3-) levels than soil L, but was more resistant to nitrite (NO2-) accumulation and produced two to ten times less N2O than soil L. Genes associated with NO2- oxidation (nxrA) increased substantially in soil W but remained static in soil L. Soil NO2- was strongly correlated with N2O production, and cumulative (c-) slNH3 explained 87% of the variance in c-NO2-. Differences between soils were explained by greater slNH3 in soil L which inhibited NO2- oxidization leading to greater NO2- levels and N2O production. This is the first study to correlate the dynamics of soil slNH3, NO2-, N2O and nitrifier genes, and the first to show how ASC can regulate NO2- levels and N2O production.

  18. Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

    NARCIS (Netherlands)

    Bollmann, A.; Laanbroek, H.J.

    2001-01-01

    Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally less

  19. Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

    NARCIS (Netherlands)

    Bollmann, A.; Laanbroek, H.J.

    2001-01-01

    Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally

  20. Revisiting the electrochemical oxidation of ammonia on carbon-supported metal nanoparticle catalysts

    International Nuclear Information System (INIS)

    Li, Zhe-Fei; Wang, Yuxuan; Botte, Gerardine G.

    2017-01-01

    Highlights: • A procedure to pretreat electrocatalysts to study the ammonia oxidation is provided. • N ads and O/OH ads were identified as the major deactivation species that prevent ammonia oxidatoin. • The electrocatalytic activity, thermodynamics, and possible deactivation mechanisms for ammonia oxidation were elucidated. • The onset potential for ammonia oxidation is related to the hydrogen binding energy of the catalyst. • Ammonia electro-oxidation involves a complex decoupled electron and proton transfer process. - Abstract: The ammonia electro-oxidation reaction (AOR) has been studied due to its promising applications in ammonia electrolysis, wastewater remediation, direct ammonia fuel cells, and sensors. However, it is difficult to compare and analyze the reported electrocatalytic activity of AOR reliably, likely due to the variation in catalyst synthesis, electrode composition, electrode morphology, and testing protocol. In this paper, the electro-oxidation of ammonia on different carbon-supported precious metal nanoparticle catalysts was revisited. The effect of experimental conditions, electrochemical test parameters, electrocatalytic activity, thermodynamics, and possible deactivation mechanism of the catalysts were investigated. Pt/C catalyst possesses the highest electrocatalytic activity, while Ir/C and Rh/C show lower overpotential. The onset potential of the AOR is related to the hydrogen binding energy of the catalyst. N ads is one major cause of deactivation accompanied with the formation of surface O/OH ads at high potentials. The coulombic efficiency of N ads formation on Pt is about 1% initially and gradually decreases with reaction time. Increase in ammonia concentration leads to increase in current density, while increase in hydroxyl ions concentration can enhance the current density and reduce the overpotential simultaneously. The slopes of AOR onset potential and hydrogen adsorption/desorption potential of Pt/C as a function of p

  1. Nitrous oxide emission from cropland and adjacent riparian buffers in contrasting hydrogeomorphic settings.

    Science.gov (United States)

    Fisher, K; Jacinthe, P A; Vidon, P; Liu, X; Baker, M E

    2014-01-01

    Riparian buffers are important nitrate (NO) sinks in agricultural watersheds, but limited information is available regarding the intensity and control of nitrous oxide (NO) emission from these buffers. This study monitored (December 2009-May 2011) NO fluxes at two agricultural riparian buffers in the White River watershed in Indiana to assess the impact of land use and hydrogeomorphologic (HGM) attributes on emission. The study sites included a riparian forest in a glacial outwash/alluvium setting (White River [WR]) and a grassed riparian buffer in tile-drained till plains (Leary Weber Ditch [LWD]). Adjacent corn ( L.) fields were monitored for land use assessment. Analysis of variance identified season, land use (riparian buffer vs. crop field), and site geomorphology as major drivers of NO fluxes. Strong relationships between N mineralization and NO fluxes were found at both sites, but relationships with other nutrient cycling indicators (C/N ratio, dissolved organic C, microbial biomass C) were detected only at LWD. Nitrous oxide emission showed strong seasonal variability; the largest NO peaks occurred in late spring/early summer as a result of flooding at the WR riparian buffer (up to 27.8 mg NO-N m d) and N fertilizer application to crop fields. Annual NO emission (kg NO-N ha) was higher in the crop fields (WR: 7.82; LWD: 6.37) than in the riparian areas. A significant difference ( LWD, respectively), and this difference was attributed to site geomorphology and flooding (WR is flood prone; no flooding occurred at tile-drained LWD). The study results demonstrate the significance of landscape geomorphology and land-stream connection (i.e., flood potential) as drivers of NO emission in riparian buffers and therefore argue that an HGM-based approach should be especially suitable for determination of regional NO budget in riparian ecosystems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Atmospheric nitrogen deposition influences denitrification and nitrous oxide production in lakes.

    Science.gov (United States)

    McCrackin, Michelle L; Elser, James J

    2010-02-01

    Microbially mediated denitrification is an important process that may ameliorate the effects of nitrogen (N) loading by permanently removing excess N inputs. In this study, we measured the rate of denitrification and nitrous oxide (N2O) production during denitrification in sediments from 32 Norwegian lakes at the high and low ends of a gradient of atmospheric N deposition. Denitrification and N2O production rates averaged 41.7 and 1.1 micromol N x m(-2) x h(-1), respectively, for high-deposition lakes. There was no detectable denitrification or N2O production in low-deposition lakes. Epilimnetic nitrate concentration was strongly correlated with denitrification rate (r2 = 0.67). We also measured the denitrification rate in response to experimental additions of organic carbon, nitrate, and phosphorus. Experimental nitrate additions stimulated denitrification in sediments of all lakes, regardless of N deposition level. In fact, the rate of denitrification in nitrate-amended treatments was the same magnitude for lakes in both deposition areas. These findings suggest that lake sediments possess considerable capacity to remove nitrate and that this capacity has not been saturated under conditions of chronic N loading. Further, nitrous oxide was nearly 3% of the total gaseous product during denitrification in high-deposition lakes, a fraction that is comparable to polluted marine sediments. Our findings suggest that, while lakes play an important role in N removal in the landscape, they may be a source of N2O emissions, especially in areas subject to elevated N inputs.

  3. Nitrogen source effects on nitrous oxide emissions from irrigated no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Francesco, Alluvione

    2010-01-01

    Nitrogen fertilization is essential for optimizing crop yields; however, it may potentially increase nitrous oxide (N2O) emissions. The study objective was to assess the ability of commercially available enhanced-efficiency N fertilizers to reduce N2O emissions following their application in comparison with conventional dry granular urea and liquid urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Four enhanced-efficiency fertilizers were evaluated: two polymer-coated urea products (ESN and Duration III) and two fertilizers containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus). Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Enhanced-efficiency fertilizers significantly reduced growing-season N2O-N emissions in comparison with urea, including UAN. SuperU and UAN+AgrotainPlus had significantly lower N2O-N emissions than UAN. Compared with urea, SuperU reduced N2O-N emissions 48%, ESN 34%, Duration III 31%, UAN 27%, and UAN+AgrotainPlus 53% averaged over 2 yr. Compared with UAN, UAN+AgrotainPlus reduced N2O emissions 35% and SuperU 29% averaged over 2 yr. The N2O-N loss as a percentage of N applied was 0.3% for urea, with all other N sources having significantly lower losses. Grain production was not reduced by the use of alternative N sources. This work shows that enhanced-efficiency N fertilizers can potentially reduce N2O-N emissions without affecting yields from irrigated NT corn systems in the semiarid central Great Plains.

  4. Nitrogen source and placement effects on soil nitrous oxide emissions from no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J

    2012-01-01

    A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (NO). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn ( L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing-season NO emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of NO emissions with no yield loss. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  5. Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Jantalia, Claudia Pozzi

    2011-01-01

    Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was <0.8% for all N sources. Corn grain yields were not different among N sources but greater than treatments with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  6. Nitrous oxide emissions from manure handling - effects of storage conditions and climate

    International Nuclear Information System (INIS)

    Sommer, S.G.; Petersen, S.O.

    2002-01-01

    Stored animal manure and manure applied in the field contributes an estimated 20% to the total anthropogenic emissions of nitrous oxide (N 2 0) in Denmark. Manure composition, handling and climatic conditions may all influence the emission level during storage, but there are relatively few experimental data on emissions of N 2 0 from manure management, including animal houses, slurry stores and manure heaps. Among animal housing systems, very high emission rates have been found with pig deep lifter, and N 2 0 emissions are further stimulated by mechanical mixing. Slurry stores are anaerobic, but a recent study showed that N 2 0 can be produced in porous surface covers such as natural surface crusts, straw or leca pebbles, while no N 2 0 was emitted from uncovered slurry. The emission was significantly related to the water balance, i.e., the difference between evaporation and rain, during dry periods; during wet periods no N 2 0 was emitted. For solid manure, previous studies have typically found that less than 1 % of total N is emitted as N 2 0. Nitrous oxide may be produced throughout the manure heap, provided an environment with both aerobic and anaerobic pockets exists. Profiles from an experimental heap indicated that most of the N 2 0 emitted from solid manure was produced near the surface of the heap. Increasing density appears to stimulate N 2 0 emissions up to a point, where the air exchange is significantly impeded. The IPCC methodology calculates N 2 0 emissions from manure on the basis of total N content (that is, on the basis of volume) and climate region only. Possibly, estimates of N 2 0 emissions from slurry stores could be improved by considering surface area, ammonium content and water balance as input variables. Emissions from solid manure heaps should consider surface area and the potential for composting, as reflected in bulk density and moisture content. (au)

  7. Marine nitrous oxide emissions: An unknown liability for the international water sector

    International Nuclear Information System (INIS)

    Short, Michael D.; Peters, Gregory M.; Peirson, William L.; Ashbolt, Nicholas J.

    2013-01-01

    Highlights: • IPCC methodology for indirect marine nitrous oxide (N 2 O) emissions does not exist. • The water sector has an unknown N 2 O emissions liability from marine sewage disposal. • We model global sewage-nitrogen (N) emissions to coastal oceans during 1970–2050. • Emission factors for marine N 2 O will enable water sector N 2 O emissions accounting. • Industry benefits will include future revenue streams and better N emissions policy. -- Abstract: Reliable estimates of anthropogenic greenhouse gas (GHG) emissions are essential for setting effective climate policy at both the sector and national level. Current IPCC Guidelines for calculating nitrous oxide (N 2 O) emissions from sewage management are both highly uncertain and incomplete; a major methodological gap relates to the calculation of indirect N 2 O emissions from sewage disposed to marine environments. Here we apply a novel approach to estimate past and future global sewage-nitrogen emissions to coastal oceans and the potential marine N 2 O emissions linked to this nitrogen source. Then, by estimating the future cost associated with this largely uncharacterized emission source, we demonstrate the industry significance of developing a methodology for estimating N 2 O emissions from marine receiving environments. The capacity to accurately estimate, monitor and report GHG emissions has important consequences for informing future policy decisions regarding both mitigation and adaptation. A robust N 2 O emissions estimation methodology for sewage-nitrogen disposed to coastal oceans will allow the international water sector to more accurately and comprehensively inventory its N 2 O emissions. This will in turn allow for proper accounting of related future emissions liabilities while also enabling the sector to capitalize on any future economic returns linked to this source – providing much-needed capital to support the sector's future infrastructure and climate change adaptation challenges

  8. Carbon Sequestration and Nitrous Oxide Emissions from Urban Turfgrass Ecosystems in Southern California

    Science.gov (United States)

    Ampleman, M. D.; Czimczik, C. I.; Townsend-Small, A.; Trumbore, S. E.

    2008-12-01

    Irrigated turfgrass ecosystems sequester carbon in soil organic matter, but they may also release nitrous oxide, due to fertilization associated with intensive management practices. Nitrous oxide is an important green house gas with a global warming potential (GWP) of 300 times that of carbon dioxide on a 100 yr time horizon. Although regular irrigation and fertilization of turfgrass create favorable conditions for both C storage and N2O release via nitrification and denitrification by soil microbes, emissions from these highly managed ecosystems are poorly constrained. We quantified N2O emissions and C storage rates for turf grass in four urban parks in the city of Irvine, CA. The turf grass systems we studied were managed by the City of Irvine. Parks were established between 1975 and 2006 on former range land with the same initial parent material; are exposed to the same climate; and form a time series (chronosequence) for investigating rates of C accumulation. We also investigated the effects of management (e.g. grass species, fertilization rate), soil moisture and temperature, and park age on N2O emission from these parks. We quantified N2O emissions using static soil chamber with four 7 min. sampling intervals, and analyzed the samples using an electron capture gas chromatograph. Soil carbon accumulation rates were determined from the slope of the organic C inventory (from 0-20 cm depth) plotted against park age. C storage rates for soils in "leisure" areas were close to 2 Mg C ha-1 yr-1, similar to rates associated with forest regrowth in northeastern US forests. However, as park age and C storage increased, N2O emissions increased as well, such that emissions from the older parks (~20 ngN m-2 s-1) were comparable to published temperate agricultural fluxes. Initial estimates suggest that the GWP associated with N2O emissions approximately offsets the effect of C storage in these ecosystems.

  9. Interannual Variability of Carbon Dioxide, Methane and Nitrous Oxide Fluxes in Subarctic European Russian Tundra

    Science.gov (United States)

    Marushchak, M. E.; Voigt, C.; Gil, J.; Lamprecht, R. E.; Trubnikova, T.; Virtanen, T.; Kaverin, D.; Martikainen, P. J.; Biasi, C.

    2017-12-01

    Southern tundra landscapes are particularly vulnerable to climate warming, permafrost thaw and associated landscape rearrangement due to near-zero permafrost temperatures. The large soil C and N stocks of subarctic tundra may create a positive feedback for warming if released to the atmosphere at increased rates. Subarctic tundra in European Russia is a mosaic of land cover types, which all play different roles in the regional greenhouse gas budget. Peat plateaus - massive upheaved permafrost peatlands - are large storehouses of soil carbon and nitrogen, but include also bare peat surfaces that act as hot-spots for both carbon dioxide and nitrous oxide emissions. Tundra wetlands are important for the regional greenhouse gas balance since they show high rates of methane emissions and carbon uptake. The most dominant land-form is upland tundra vegetated by shrubs, lichens and mosses, which displays a close-to-neutral balance with respect to all three greenhouse gases. The study site Seida (67°03'N, 62°56'E), located in the discontinuous permafrost zone of Northeast European Russia, incorporates all these land forms and has been an object for greenhouse gas investigations since 2007. Here, we summarize the growing season fluxes of carbon dioxide, methane and nitrous oxide measured by chamber techniques over the study years. We analyzed the flux time-series together with the local environmental data in order to understand the drivers of interannual variability. Detailed soil profile measurements of greenhouse gas concentrations, soil moisture and temperature provide insights into soil processes underlying the net emissions to the atmosphere. The multiannual time-series allows us to assess the importance of the different greenhouse gases and landforms to the overall climate forcing of the study region.

  10. An inventory of nitrous oxide emissions from agriculture in the UK using the IPCC methodology: emission estimate, uncertainty and sensitivity analysis

    Science.gov (United States)

    Brown, L.; Armstrong Brown, S.; Jarvis, S. C.; Syed, B.; Goulding, K. W. T.; Phillips, V. R.; Sneath, R. W.; Pain, B. F.

    Nitrous oxide emission from UK agriculture was estimated, using the IPCC default values of all emission factors and parameters, to be 87 Gg N 2O-N in both 1990 and 1995. This estimate was shown, however, to have an overall uncertainty of 62%. The largest component of the emission (54%) was from the direct (soil) sector. Two of the three emission factors applied within the soil sector, EF1 (direct emission from soil) and EF3 PRP (emission from pasture range and paddock) were amongst the most influential on the total estimate, producing a ±31 and +11% to -17% change in emissions, respectively, when varied through the IPCC range from the default value. The indirect sector (from leached N and deposited ammonia) contributed 29% of the total emission, and had the largest uncertainty (126%). The factors determining the fraction of N leached (Frac LEACH) and emissions from it (EF5), were the two most influential. These parameters are poorly specified and there is great potential to improve the emission estimate for this component. Use of mathematical models (NCYCLE and SUNDIAL) to predict Frac LEACH suggested that the IPCC default value for this parameter may be too high for most situations in the UK. Comparison with other UK-derived inventories suggests that the IPCC methodology may overestimate emission. Although the IPCC approach includes additional components to the other inventories (most notably emission from indirect sources), estimates for the common components (i.e. fertiliser and animals), and emission factors used, are higher than those of other inventories. Whilst it is recognised that the IPCC approach is generalised in order to allow widespread applicability, sufficient data are available to specify at least two of the most influential parameters, i.e. EF1 and Frac LEACH, more accurately, and so provide an improved estimate of nitrous oxide emissions from UK agriculture.

  11. Mathematical modeling of nitrous oxide production in an anaerobic/oxic/anoxic process.

    Science.gov (United States)

    Ding, Xiaoqian; Zhao, Jianqiang; Hu, Bo; Chen, Ying; Ge, Guanghuan; Li, Xiaoling; Wang, Sha; Gao, Kun; Tian, Xiaolei

    2016-12-01

    This study incorporates three currently known nitrous oxide (N 2 O) production pathways: ammonium-oxidizing bacteria (AOB) denitrification, incomplete hydroxylamine (NH 2 OH) oxidation, and heterotrophic denitrification on intracellular polymers, into a mathematical model to describe N 2 O production in an anaerobic/oxic/anoxic (AOA) process for the first time. The developed model was calibrated and validated by four experimental cases, then evaluated by two independent anaerobic/aerobic (AO) studies from literature. The modeling results displayed good agreement with the measured data. N 2 O was primarily generated in the aerobic stage by AOB denitrification (67.84-81.64%) in the AOA system. Smaller amounts of N 2 O were produced via incomplete NH 2 OH oxidation (15.61-32.17%) and heterotrophic denitrification on intracellular polymers (0-12.47%). The high nitrite inhibition on N 2 O reductase led to the increased N 2 O accumulation in heterotrophic denitrification on intracellular polymers. The new model was capable of modeling nitrification-denitrification dynamics and heterotrophic denitrification on intracellular polymers in the AOA system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Oxidative destruction of ammonia for restoration of uranium solution mining sites

    International Nuclear Information System (INIS)

    Humenick, M.J.; Garwacka, K.

    1984-01-01

    A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process

  13. Oxidative destruction of ammonia for restoration of uranium solution mining sites

    Energy Technology Data Exchange (ETDEWEB)

    Humenick, M.J.; Garwacka, K.

    1984-02-01

    A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

  14. Oxidative destruction of ammonia for restoration of uranium solution mining sites

    Energy Technology Data Exchange (ETDEWEB)

    Humenick, M.J.; Garwacka, K.

    1984-01-01

    A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

  15. Quantification of nitrous oxide (N2O) emissions and soluble microbial product (SMP) production by a modified AOB-NOB-N2O-SMP model.

    Science.gov (United States)

    Kim, MinJeong; Wu, Guangxue; Yoo, ChangKyoo

    2017-03-01

    A modified AOB-NOB-N 2 O-SMP model able to quantify nitrous oxide (N 2 O) emissions and soluble microbial product (SMP) production during wastewater treatment is proposed. The modified AOB-NOB-N 2 O-SMP model takes into account: (1) two-step nitrification by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), (2) N 2 O production by AOB denitrification under oxygen-limited conditions and (3) SMP production by microbial growth and endogenous respiration. Validity of the modified model is demonstrated by comparing the simulation results with experimental data from lab-scale sequencing batch reactors (SBRs). To reliably implement the modified model, a model calibration that adjusts model parameters to fit the model outputs to the experimental data is conducted. The results of this study showed that the modeling accuracy of the modified AOB-NOB-N 2 O-SMP model increases by 19.7% (NH 4 ), 51.0% (NO 2 ), 57.8% (N 2 O) and 16.7% (SMP) compared to the conventional model which does not consider the two-step nitrification and SMP production by microbial endogenous respiration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Full-Scale Modeling Explaining Large Spatial Variations of Nitrous Oxide Fluxes in a Step-Feed Plug-Flow Wastewater Treatment Reactor.

    Science.gov (United States)

    Ni, Bing-Jie; Pan, Yuting; van den Akker, Ben; Ye, Liu; Yuan, Zhiguo

    2015-08-04

    Nitrous oxide (N2O) emission data collected from wastewater treatment plants (WWTPs) show huge variations between plants and within one plant (both spatially and temporarily). Such variations and the relative contributions of various N2O production pathways are not fully understood. This study applied a previously established N2O model incorporating two currently known N2O production pathways by ammonia-oxidizing bacteria (AOB) (namely the AOB denitrification and the hydroxylamine pathways) and the N2O production pathway by heterotrophic denitrifiers to describe and provide insights into the large spatial variations of N2O fluxes in a step-feed full-scale activated sludge plant. The model was calibrated and validated by comparing simulation results with 40 days of N2O emission monitoring data as well as other water quality parameters from the plant. The model demonstrated that the relatively high biomass specific nitrogen loading rate in the Second Step of the reactor was responsible for the much higher N2O fluxes from this section. The results further revealed the AOB denitrification pathway decreased and the NH2OH oxidation pathway increased along the path of both Steps due to the increasing dissolved oxygen concentration. The overall N2O emission from this step-feed WWTP would be largely mitigated if 30% of the returned sludge were returned to the Second Step to reduce its biomass nitrogen loading rate.

  17. Bacterial domination over Archaea in ammonia oxidation in a monsoon-driven tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Vipindas, P.V.; Anas, A.; Jasmin, C.; Lallu, K.R.; Fausia, K.H.; Balachandran, K.K.; Muraleedharan, K.R.; Nair, S.

    Autotrophic ammonia oxidizing microorganisms,which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon...

  18. Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

    DEFF Research Database (Denmark)

    Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

    2015-01-01

    tested in the study; which is contradicting to the general belief that thermophilic methanogens are more vulnerable to high ammonia loads compared to mesophilic. This unexpected finding underlines the fact that the complete knowledge of ammonia inhibition effect on hydrogenotrophic methanogens is still...

  19. The oxidation of hydroxylamine by nitric and nitrous acids in the presence of technetium (VII)

    International Nuclear Information System (INIS)

    Koltunov, V.S.; Gomonova, T.V.; Savilova, O.A.; Zhuravleva, G.I.

    2000-01-01

    The oxidation of hydroxylamine by nitric acid in the presence of technetium ions at temperatures above ∝60 C is an autocatalytic process comprising an induction period and then a catalysed reaction involving HNO 2 , which has accumulated in the solution. Tc ions have no appreciable effect on the reaction rate, which is governed only by the nitric and nitrous acid oxidation reactions of hydroxylamine, but the presence of Tc ions does extend the initial induction period. The rate of hydroxylamine oxidation by HNO 3 in the presence of HNO 2 , that is, after the induction period, was found to be: -d[NH 3 OH + ]/dt = k[NH 3 OH + ][HNO 2 ][HNO 3 ] 3.5 where k = 120 ± 10 l 4.5 mol -4.5 min -1 at T = 80 C, μ = 2 and [H + ] ≤ 2 M. Under these conditions, the reaction apparently has a high activation energy of 160-180 kJ mol -1 . At low temperatures (20-40 C) hydroxylamine is effectively stable in solutions of HNO 3 up to concentrations of ∝2 M, whether or not Tc(VII) ions are present. Tc(V) was also observed to form at least one complex on reduction with excess hydroxylamine with an absorption maximum between 467 and 480 nm dependent on the solution acidity. (orig.)

  20. Identification of key nitrous oxide production pathways in aerobic partial nitrifying granules.

    Science.gov (United States)

    Ishii, Satoshi; Song, Yanjun; Rathnayake, Lashitha; Tumendelger, Azzaya; Satoh, Hisashi; Toyoda, Sakae; Yoshida, Naohiro; Okabe, Satoshi

    2014-10-01

    The identification of the key nitrous oxide (N2O) production pathways is important to establish a strategy to mitigate N2O emission. In this study, we combined real-time gas-monitoring analysis, (15)N stable isotope analysis, denitrification functional gene transcriptome analysis and microscale N2O concentration measurements to identify the main N2O producers in a partial nitrification (PN) aerobic granule reactor, which was fed with ammonium and acetate. Our results suggest that heterotrophic denitrification was the main contributor to N2O production in our PN aerobic granule reactor. The heterotrophic denitrifiers were probably related to Rhodocyclales bacteria, although different types of bacteria were active in the initial and latter stages of the PN reaction cycles, most likely in response to the presence of acetate. Hydroxylamine oxidation and nitrifier denitrification occurred, but their contribution to N2O emission was relatively small (20-30%) compared with heterotrophic denitrification. Our approach can be useful to quantitatively examine the relative contributions of the three pathways (hydroxylamine oxidation, nitrifier denitrification and heterotrophic denitrification) to N2O emission in mixed microbial populations. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.