WorldWideScience

Sample records for acquire organic nitrogen

  1. Degradation of proteins by enzymes exuded by Allium porrum roots - a potentially important strategy for acquiring organic nitrogen by plants.

    Science.gov (United States)

    Adamczyk, Bartosz; Godlewski, Mirosław; Smolander, Aino; Kitunen, Veikko

    2009-10-01

    Nitrogen is one of the crucial elements that regulate plant growth and development. It is well-established that plants can acquire nitrogen from soil in the form of low-molecular-mass compounds, namely nitrate and ammonium, but also as amino acids. Nevertheless, nitrogen in the soil occurs mainly as proteins or proteins complexed with other organic compounds. Proteins are believed not to be available to plants. However, there is increasing evidence to suggest that plants can actively participate in proteolysis by exudation of proteases by roots and can obtain nitrogen from digested proteins. To gain insight into the process of organic nitrogen acquisition from proteins by leek roots (Allium porrum L. cv. Bartek), casein, bovine serum albumin and oxidized B-chain of insulin were used; their degradation products, after exposure to plant culture medium, were studied using liquid chromatography-mass spectrometry (LC-MS). Casein was degraded to a great extent, but the level of degradation of bovine serum albumin and the B-chain of insulin was lower. Proteases exuded by roots cleaved proteins, releasing low-molecular-mass peptides that can be taken up by roots. Various peptide fragments produced by digestion of the oxidized B-chain of insulin suggested that endopeptidase, but also exopeptidase activity was present. After identification, proteases were similar to cysteine protease from Arabidopsis thaliana. In conclusion, proteases exuded by roots may have great potential in the plant nitrogen nutrition.

  2. Improvements to the Characterization of Organic Nitrogen Chemistry

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  3. The Atmospheric Fate of Organic Nitrogen Compounds

    Science.gov (United States)

    Borduas, Nadine

    Organic nitrogen compounds are present in our atmosphere from biogenic and anthropogenic sources and have impacts on air quality and climate. Due to recent advances in instrumentation, these compounds are being detected in the gas and particle phases, raising questions as to their source, processing and sinks in the environment. With their recently identified role as contributors to aerosol formation and growth, their novel large scale use as solvents in carbon capture and storage (CCS) technology and their emissions from cigarette smoke, it is now important to address the gaps in our understanding of the fate of organic nitrogen. Experimentally and theoretically, I studied the chemical atmospheric fate of specific organic nitrogen compounds in the amine, amide and isocyanate families, yielding information that can be used in chemical transport models to assess the fate of this emerging class of atmospheric molecules. I performed kinetic laboratory studies in a smog chamber to measure the room temperature rate coefficient for reaction with the hydroxyl radical of monoethanolamine, nicotine, and five different amides. I employed online-mass spectrometry techniques to quantify the oxidation products. I found that amines react quickly with OH radicals with lifetimes of a few hours under sunlit conditions, producing amides as oxidation products. My studies on amides revealed that they have much longer lifetimes in the atmosphere, ranging from a few hours to a week. Photo-oxidation of amides produces isocyanates and I investigated these mechanisms in detail using ab initio calculations. Furthermore, I experimentally measured isocyanic acid's Henry's Law constant as well as its hydrolysis rate constants to better understand its sinks in the atmosphere. Finally, I re-examined the structure-activity relationship (SAR) of organic nitrogen molecules for improved model parameterizations.

  4. Worldwide organic soil carbon and nitrogen data

    Energy Technology Data Exchange (ETDEWEB)

    Zinke, P.J.; Stangenberger, A.G. [Univ. of California, Berkeley, CA (United States). Dept. of Forestry and Resource Management; Post, W.M.; Emanual, W.R.; Olson, J.S. [Oak Ridge National Lab., TN (United States)

    1986-09-01

    The objective of the research presented in this package was to identify data that could be used to estimate the size of the soil organic carbon pool under relatively undisturbed soil conditions. A subset of the data can be used to estimate amounts of soil carbon storage at equilibrium with natural soil-forming factors. The magnitude of soil properties so defined is a resulting nonequilibrium values for carbon storage. Variation in these values is due to differences in local and geographic soil-forming factors. Therefore, information is included on location, soil nitrogen content, climate, and vegetation along with carbon density and variation.

  5. Dissolved Organic Nitrogen in Mediterranean Ecosystems

    Institute of Scientific and Technical Information of China (English)

    M.DELGADO-BAQUERIZO; F.COVELO; A.GALLARDO

    2011-01-01

    Dissolved organic nitrogen (DON) in soils has recently gained increasing interest because it may be both a direct N source for plants and the dominant available N form in nutrient-poor soils, however, its prevalence in Mediterranean ecosystems remains unclear. The aims of this study were to i) estimate soil DON in a wide set of Mediterranean ecosystems and compare this levels with those for other ecosystems; ii) describe temporal changes in DON and dissolved inorganic nitrogen (DIN) forms (NH4+ and NO3-), and characterize spatial heterogeneity within plant communities; and iii) study the relative proportion of soil DON and DIN forms as a test of Schimel and Bennett's hypothesis that the prevalence of different N forms follows a gradient of nutrient availability. The study was carried out in eleven plant communities chosen to represent a wide spectrum of Mediterranean vegetation types, ranging from early to late successional status. DON concentrations in the studied Mediterranean plant communities (0-18.2 mg N kg-1) were consistently lower than those found in the literature for other ecosystems. We found high temporal and spatial variability in soil DON for all plant communities. As predicted by the Schimel and Bennett model for nutrient-poor ecosystems, DON dominance over ammonium and nitrate was observed for most plant communities in winter and spring soil samples. However, mineral-N dominated over DON in summer and autumn. Thus, soil water content may have an important effect on DON versus mineral N dominance in Mediterranean ecosystems.

  6. SOIL CONTAMINATION BY NITROGEN COMPOUNDS DURING ORGANIC FUEL COMBUSTION

    Directory of Open Access Journals (Sweden)

    V. P. Bubnov

    2010-01-01

    Full Text Available The paper considers a transition mechanism of flue gas nitrogen oxides being formed due to organic fuel combustion from atmosphere into soil. Mechanisms of nitrogen compound origination and transformation in atmosphere and their transition into soil have been presented in the paper. The paper recommends a generalized equation for mathematical description of nitrogen migration into soil. 

  7. Harvesting of organic nitrogen from intercropped Leucaena

    Energy Technology Data Exchange (ETDEWEB)

    Palled, Y.B.; Hosmani, M.M.; Patil, M.P.

    1983-01-01

    Maize was sown on 6 June 1981 and interplanted with Leucaena leucocephala variety K8 at 45 days in the ratios of 1:1 - 1:5 rows. After harvesting the maize, the Leucaena was cut and total DM production and nitrogen uptake were calculated. Both DM production and nitrogen uptake were greatest when maize was intercropped with Leucaena at 1:5 rows. This nitrogen uptake (85.56 kg/ha) can meet 60-100% of the nitrogen requirements of some crops. 1 reference.

  8. Alternate Nitrogen Amendments for Organic Fertilizers

    Directory of Open Access Journals (Sweden)

    M.K.C. Sridhar

    2001-01-01

    Full Text Available The use of compost or manure in agriculture as an organic source of nutrients is common in many tropical, developing countries like Nigeria. One of the drawbacks of such materials is their low nitrogen (N content (=1% N. Farmers commonly use chemical N fertilizers such as urea, calcium ammonium nitrate (CAN, and NPK formulations to obtain better crop growth and yield. These chemical supplements may have a negative impact on the environment through nitrate leaching into water, leading to eutrophication of surface waters that can affect public health. Gliricidia sepium, a fast-growing, tropical, perennial hedge plant was tested as a source of N in organo-mineral fertilizer formulations. Average nutrient content of Gliricidia is 3.8% N, 0.32% P, 1.8% K, 0.8% Ca, and 0.2% Mg. Using a sand culture and Amaranthus caudatus as a test crop, it was shown that amending commercial composts with 30% Gliricidia prunings would benefit many small-scale farmers and control environmental pollution.

  9. Degradation of organic nitrogenous wastes by a soil streptomycete.

    Science.gov (United States)

    De, S; Chandra, A L

    1979-01-01

    A soil streptomycete degraded hair, silk, wool, feather and leather which were collected from solid wastes. The organism was identified taxonomically and designated Streptomyces sp. A956. It degraded leather to the maximum extent and solubilized 35.9% of the total nitrogen, 2.32 mg of glycine equivalent amino nitrogen could be obtained by degradation of 100 mg leather.

  10. Identifying nitrogen-efficient potato cultivars for organic farming

    NARCIS (Netherlands)

    Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P.C.

    2014-01-01

    In organic farming, nitrogen efficiency of potato might vary among cultivars, even within the same maturity type. We therefore analysed in depth the response to nitrogen of a diverse set of cultivars, grown at different locations (differing in soil type and management) and in four years (differing i

  11. Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles

    CERN Document Server

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Bernard, Sylvain; Rigaudier, Thomas; Fleury, Benjamin; Tissandier, Laurent

    2014-01-01

    The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for overall comprehension of organic formation in the young solar system and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2-CH4 and N2-CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titan s atmosphere and in the protosolar nebula, respectively. Nitrogen is efficiently incorporated into the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols. The aerosols are depleted in 15N by 15-25 permil relative to the initial N2 gas, whatever the experimental set...

  12. Chemical composition of dissolved organic nitrogen in the ocean

    Science.gov (United States)

    McCarthy, Matthew; Pratum, Tom; Hedges, John; Benner, Ronald

    1997-11-01

    Fixed nitrogen is one of the main limiting nutrients for primary production in the ocean, where it is biologically available in the form of dissolved inorganic and organic matter. Inorganic nitrogen concentrations are consequently very low in surface waters of temperate ocean gyres, yet fixed nitrogen persists in the form of dissolved organic matter. The small, rapidly cycling organic compounds fundamental to microbial and planktonic growth (such as free amino acids, amines and urea) account for only a minor fraction of total dissolved organic nitrogen (DON). In contrast, the vast majority of DON, especially in the deep ocean, resides in the form of nitrogenous substances that are resistant to biological degradation. These substances, which represent an enormous reservoir of fixed nitrogen, are not readily identified by conventional biochemical techniques, but have been assumed to consist largely of structurally complex macromolecules resulting from the degradation and spontaneous abiotic condensation of biochemical precursors. Here we present 15N NMR measurements that contradict this view. Our results show that most higher-molecular-weight DON in the ocean exists in amide form, rather than as a collection of nitrogen heterocycles that might be indicative of spontaneous condensation products. Because these amides are unlikely to form abiotically, the bulk of the ocean's DON reservoir appears to derive directly from degradation-resistant biomolecules.

  13. Carbon and nitrogen isotopic signatures and nitrogen profile to identify adulteration in organic fertilizers.

    Science.gov (United States)

    Verenitch, Sergei; Mazumder, Asit

    2012-08-29

    Recently it has been shown that stable isotopes of nitrogen can be used to discriminate between organic and synthetic fertilizers, but the robustness of the approach is questionable. This work developed a comprehensive method that is far more robust in identifying an adulteration of organic nitrogen fertilizers. Organic fertilizers of various types (manures, composts, blood meal, bone meal, fish meal, products of poultry and plant productions, molasses and seaweed based, and others) available on the North American market were analyzed to reveal the most sensitive criteria as well as their quantitative ranges, which can be used in their authentication. Organic nitrogen fertilizers of known origins with a wide δ(15)N range between -0.55 and 28.85‰ (n = 1258) were characterized for C and N content, δ(13)C, δ(15)N, viscosity, pH, and nitrogen profile (urea, ammonia, organic N, water insoluble N, and NO3). A statistically significant data set of characterized unique organic nitrogen fertilizers (n = 335) of various known origins has been assembled. Deliberately adulterated samples of different types of organic fertilizers mixed with synthetic fertilizers at a wide range of proportions have been used to develop the quantitative critical characteristics of organic fertilizers as the key indicators of their adulteration. Statistical analysis based on the discriminant functions of the quantitative critical characteristics of organic nitrogen fertilizers from 14 different source materials revealed a very high average rate of correct classification. The developed methodology has been successfully used as a source identification tool for numerous commercial nitrogen fertilizers available on the North American market.

  14. Molecular signature of organic nitrogen in septic-impacted groundwater

    Science.gov (United States)

    Arnold, William A.; Longnecker, Krista; Kroeger, Kevin D.; Kujawinski, Elizabeth B.

    2014-01-01

    Dissolved inorganic and organic nitrogen levels are elevated in aquatic systems due to anthropogenic activities. Dissolved organic nitrogen (DON) arises from various sources, and its impact could be more clearly constrained if specific sources were identified and if the molecular-level composition of DON were better understood. In this work, the pharmaceutical carbamazepine was used to identify septic-impacted groundwater in a coastal watershed. Using ultrahigh resolution mass spectrometry data, the nitrogen-containing features of the dissolved organic matter in septic-impacted and non-impacted samples were compared. The septic-impacted groundwater samples have a larger abundance of nitrogen-containing formulas. Impacted samples have additional DON features in the regions ascribed as ‘protein-like’ and ‘lipid-like’ in van Krevelen space and have more intense nitrogen-containing features in a specific region of a carbon versus mass plot. These features are potential indicators of dissolved organic nitrogen arising from septic effluents, and this work suggests that ultrahigh resolution mass spectrometry is a valuable tool to identify and characterize sources of DON.

  15. Dissolved organic nitrogen transformation in river water: Effects of suspended sediment and organic nitrogen concentration

    Science.gov (United States)

    Xia, Xinghui; Liu, Ting; Yang, Zhifeng; Zhang, Xueqing; Yu, Zhongbo

    2013-03-01

    SummaryHigh suspended sediment (SPS) concentration exists in many Asian rivers. In addition, human activities and climate change can change river runoff, leading to the variation of SPS and pollutant concentrations. In this research, the effects of SPS and dissolved organic nitrogen (DON) concentration on DON transformation in river systems were studied through simulation experiments with samples collected from the Yellow River which is famous for its high SPS concentration. The results indicated that high DON concentration resulted in a longer retention time of NH4+-N and NO2--N in the system due to the inhibition effect of ammonia on nitrification. The re-suspension of sediment accelerated DON transformation, and both the ammonification and nitrification rates increased with SPS concentration. The ammonification rate constants obtained from the first-order kinetics were 0.286, 0.332, 0.538 day-1; the nitrification rate constants obtained from the Logistic model were 0.0018, 0.0038, 0.005 day-1 μmol-1 L-1 for the systems with SPS concentration of 0, 5, 10 g L-1, respectively. Bacteria tended to attach onto SPS, and the specific growth rate in the systems with SPS was approximately two orders of magnitude higher than that without SPS in the first 3 days of cultivation, which resulted in an increase of DON transformation rate with SPS concentration. This study implied that DON transformation rate may be lower in the dry season than that in the wet season, and nitrogen transformation will be affected by the variation of river runoff and SPS concentration.

  16. Soluble organic nitrogen in forest soils of northeast China

    Institute of Scientific and Technical Information of China (English)

    SONG Li-chen; HAO Jing-mei; CUI Xiao-yang

    2008-01-01

    Soluble organic nitrogen (SON) is recognized as a sensitive indicator of soil nitrogen status. The present work was conducted in the temperate forests of northeast China where soils are typically characterized by high organic matter and high organic nitrogen content, and soil sampling was made in early spring just after the freeze-thaw period. The water extracted SON pools in the organic layer of forest soils were measured within the range from 156.0 mg·kg-1 to 292.6 mg·kg-1, a similar magnitude of salt solution extracted SON pools reported in literatures. However, the water soluble SON pools in 0-15 cm mineral soils in present study were much higher (3-10 times) than any other reports, ranging from 58.6 mg·kg-1 to 125.2 mg·kg-1. Water soluble SON varied markedly among the soils under different forests and at different sites. The SON in water extracts were positively and significantly correlated to soil organic matter and total nitrogen contents, but negatively correlated to microbial biomass nitrogen (MBN). The reasons of the abnormally large SON pools and the negative correlations between SON and MBN in the 0-15cm mineral soils in this study were specially discussed.

  17. Adsorption of Compounds that Mimic Urban Stormwater Dissolved Organic Nitrogen.

    Science.gov (United States)

    Mohtadi, Mehrdad; James, Bruce R; Davis, Allen P

    2017-02-01

      Stormwater runoff carrying nitrogen can accelerate eutrophication. Bioretention facilities are among low impact development systems which are commonly used to manage urban stormwater quality and quantity. They are, however, not designed to remove dissolved organic nitrogen (DON) and may become a net DON exporter. Adsorption of seven organic nitrogenous compounds onto several adsorbents was examined. Batch adsorption study revealed that coal activated carbon (AC) exhibited the best performance in adsorption of the selected organic nitrogenous compounds. The highest adsorption capacity of coal AC was 0.4 mg N/g for pyrrole at an equilibrium concentration of 0.02 mg N/L, while adsorption was not detectable for urea at the same equilibrium concentration. The fastest compound to reach equilibrium adsorption capacity onto the coal AC was pyrrole (1 hour). The adsorption capacity of the coal AC for pyrrole and N-acetyl-d-glucosamine and 1-hour contact time is recommended for designing bioretention systems targeting organic nitrogenous compounds.

  18. Volatile organic compounds and oxides of nitrogen. Further emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Froste, H. [comp.

    1996-12-31

    This report presents the current status in relation to achievement of the Swedish Environmental target set by Parliament to reduce emission of volatile organic compounds by 50 per cent between 1988 and 2000. It also instructed the Agency to formulate proposed measures to achieve a 50 per cent reduction of emission of nitrogen oxides between 1985 and 2005. The report presents an overall account of emission trends for volatile organic compounds (from all sectors) and nitrogen oxides (from the industry sector) and steps proposed to achieve further emission reductions. 43 refs

  19. [Vertical Distribution Characteristics of Typical Forest Soil Organic Nitrogen in Dawei Mountain].

    Science.gov (United States)

    Ding, Xian-qing; Ma, Hui-jing; Zhu, Xiao-long; Chen, Shan; Hou, Hong-bo; Peng, Pei-qin

    2015-10-01

    To clarify altitudinal gradient of subtropical forest soil total nitrogen and organic nitrogen, soil samples were collected per 10 cm on soil profile (0-100 cm) in Dawei Mountain, researched the variation of soil organic nitrogen and correlation with soil physical and chemical properties. The results showed that: (1) Total nitrogen, acid hydrolysable organic nitrogen and soluble organic nitrogen decreased with the increase of depth, content of each component in mountain granite yellow-brown soils was much higher affected by altitude; (2) The average percentage of soil organic nitrogen to total nitrogen was 97.39% ± 1.17%, and soil acid hydrolysable organic nitrogen was 64.38% ± 10.68%, each component decreased with the increase of soil depth; (3) Soil soluble organic nitrogen content was 9.92- 23.45 mg x kg(-1), free amino acids (1.62 - 12.02 mg x kg(-1)) accounted for about 27.36% ± 9.95% of soluble organic nitrogen; (4) Soil acid hydrolysable organic nitrogen and soluble organic nitrogen were significantly positively correlated with total nitrogen, total soluble nitrogen and inorganic nitrogen (P soil bulk density, organic carbon, and total phosphorus (P nitrogen was the main body of soil nitrogen in typical subtropical forest, each component showed a downward trend increase with soil depth affected by altitude and soil physical and chemical properties. There was a close conversion relationship between soil organic nitrogen and other nitrogen forms, the characteristics of soil organic nitrogen will have profound impact on nitrogen cycling of forest ecological system.

  20. Effects of nitrogen application on grain nitrogen content, deoxinivalenol contamination and weeds in organic wheat

    NARCIS (Netherlands)

    Burgt, van der G.J.H.M.; Timmermans, B.G.H.; Scholberg, J.M.S.; Osman, A.M.

    2011-01-01

    Many studies have evaluated the effects of nitrogen-fertilizer rates on Fusarium head blight (FHB) and mycotoxin contamination of wheat (Triticum aestivum) in both conventional and organic systems. Results are often conflicting while underlying mechanisms remain illusive. This study aimed to provide

  1. Improvements to the characterization of organic nitrogen chemistry and deposition in CMAQ (CMAS Presentation)

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  2. Improvements to the characterization of organic nitrogen chemistry and deposition in CMAQ

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  3. Improvements to the treatment of organic nitrogen chemistry & deposition in CMAQ

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  4. Bioavailability of autochthonous dissolved organic nitrogen in marine plankton communities

    DEFF Research Database (Denmark)

    Knudsen, Helle; Markager, Svend Stiig; Søndergaard, Morten

    The purpose of this study was to investigate the bioavailability of dissolved organic nitrogen (DON) produced during a phytoplankton bloom. The experiments were conducted with natural plankton communities as batch growth experiments over approximately 30 days with nitrogen limitation. Five to six...... times during the exponential and stationary phases of each experimental bloom the bioavailability of DON was measured over 60 days together with DOC and oxygen consumption. The overall aim was to quantify remineralization of the added nitrate. The results showed that maximum 33 % of the added nitrate...

  5. Substantial nitrogen acquisition by arbuscular mycorrhizal fungi from organic material has implications for N cycling.

    Science.gov (United States)

    Hodge, Angela; Fitter, Alastair H

    2010-08-03

    Arbuscular mycorrhizal (AM) fungi are obligate biotrophs that acquire carbon (C) solely from host plants. AM fungi can proliferate hyphae in, and acquire nitrogen (N) from, organic matter. Although they can transfer some of that N to plants, we tested the hypothesis that organic matter is an important N source for the AM fungi themselves. We grew pairs of plants with and without the AM fungus Glomus hoi in microcosms that allowed only the fungus access to a 15N/13C-labeled organic patch; in some cases, one plant was shaded to reduce C supply to the fungus. The fungal hyphae proliferated vigorously in the patch, irrespective of shading, and increased plant growth and N content; approximately 3% of plant N came from the patch. The extraradical mycelium of the fungus was N-rich (3-5% N) and up to 31% of fungal N came from the patch, confirming the hypothesis. The fungus acquired N as decomposition products, because hyphae were not 13C-enriched. In a second experiment, hyphae of both G. hoi and Glomus mosseae that exploited an organic material patch were also better able to colonize a new host plant, demonstrating a fungal growth response. These findings show that AM fungi can obtain substantial amounts of N from decomposing organic materials and can enhance their fitness as a result. The large biomass and high N demand of AM fungi means that they represent a global N pool equivalent in magnitude to fine roots and play a substantial and hitherto overlooked role in the nitrogen cycle.

  6. Acquiring beam data for a flattening-filter free linear accelerator using organic scintillators

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Behrens, C.F.; Hoffmann, L.;

    2013-01-01

    -resolved dosimetry on a highly detailed level. In this study, we present beam data for a Varian TrueBeam linear accelerator, which is capable of delivering flattening-filter free (FFF1) clinical X-ray beams. The beam data have been acquired using an in-house developed dosimetry system based on fibre-coupled organic...

  7. Nitrogen isotopic fractionation during abiotic synthesis of organic solid particles

    Science.gov (United States)

    Kuga, Maïa; Carrasco, Nathalie; Marty, Bernard; Marrocchi, Yves; Bernard, Sylvain; Rigaudier, Thomas; Fleury, Benjamin; Tissandier, Laurent

    2014-05-01

    The formation of organic compounds is generally assumed to result from abiotic processes in the Solar System, with the exception of biogenic organics on Earth. Nitrogen-bearing organics are of particular interest, notably for prebiotic perspectives but also for overall comprehension of organic formation in the young Solar System and in planetary atmospheres. We have investigated abiotic synthesis of organics upon plasma discharge, with special attention to N isotope fractionation. Organic aerosols were synthesized from N2-CH4 and N2-CO gaseous mixtures using low-pressure plasma discharge experiments, aimed at simulating chemistry occurring in Titan's atmosphere and in the protosolar nebula, respectively. The nitrogen content, the N speciation and the N isotopic composition were analyzed in the resulting organic aerosols. Nitrogen is efficiently incorporated into the synthesized solids, independently of the oxidation degree, of the N2 content of the starting gas mixture, and of the nitrogen speciation in the aerosols. The aerosols are depleted in 15N by 15-25‰ relative to the initial N2 gas, whatever the experimental setup is. Such an isotopic fractionation is attributed to mass-dependent kinetic effect(s). Nitrogen isotope fractionation upon electric discharge cannot account for the large N isotope variations observed among Solar System objects and reservoirs. Extreme N isotope signatures in the Solar System are more likely the result of self-shielding during N2 photodissociation, exotic effect during photodissociation of N2 and/or low temperature ion-molecule isotope exchange. Kinetic N isotope fractionation may play a significant role in the Titan's atmosphere. On the Titan's night side, 15N-depletion resulting from electron driven reactions may counterbalance photo-induced 15N enrichments occurring on the day's side. We also suggest that the low δ15N values of Archaean organic matter (Beaumont and Robert, 1999) are partly the result of abiotic synthesis of

  8. [Characteristics of organic nitrogen mineralization in organic waste compost-amended soil].

    Science.gov (United States)

    Zhang, Xu; Xi, Bei-Dou; Zhao, Yue; Wei, Zi-Min; Li, Yang; Zhao, Xin-Yu

    2013-06-01

    A laboratory aerobic incubation experiment was conducted under a constant temperature to investigate the differentiation rule of nitrogen form among soils amended with different organic wastes composted with food waste, chicken manure, cow manure, domestic waste, vegetable residue, sludge, turf and tomato residue. Experiment utilized soils amended with 0%, 5% and 50% (m/m) of eight organic waste composts. The purpose was to understand the effect of different organic wastes on nitrogen mineralization in soil. This study deals with eight organic waste compost treatments could rapidly increase NH4(+) -N concentrations, reduce the NO3(-)-N concentrations and promote nitrogen mineralization in soil after 3-4 weeks incubation. All parameter tended to be stable. The improved amplitude of the same compost-amended soil: 30% compost treatments > 15% compost treatments > 5% compost treatments. Within the same proportion, chicken manure compost, turf compost and sludge compost product treatments' relative N mineralization was higher than other compost product treatments, and the chicken manure compost treatment's relative N mineralization was significantly higher than other compost product treatments. Food waste compost and vegetable residue compost product treatments' mineralization was low, the lowest was domestic waste compost product treatment. All compost treatments could significantly improve the values of potentially mineralizable nitrogen(N(0)), mineralization rate (k), and promote nitrogen mineralization in soil. The results illustrated that the effect of organic waste compost on the mineralization of nitrogen varied with types of compost and the amount of input compost.

  9. The effect of hydraulic lift on organic matter decomposition, soil nitrogen cycling, and nitrogen acquisition by a grass species.

    Science.gov (United States)

    Armas, Cristina; Kim, John H; Bleby, Timothy M; Jackson, Robert B

    2012-01-01

    Hydraulic lift (HL) is the passive movement of water through plant roots, driven by gradients in water potential. The greater soil-water availability resulting from HL may in principle lead to higher plant nutrient uptake, but the evidence for this hypothesis is not universally supported by current experiments. We grew a grass species common in North America in two-layer pots with three treatments: (1) the lower layer watered, the upper one unwatered (HL), (2) both layers watered (W), and (3) the lower layer watered, the upper one unwatered, but with continuous light 24 h a day to limit HL (no-HL). We inserted ingrowth cores filled with enriched-nitrogen organic matter ((15)N-OM) in the upper layer and tested whether decomposition, mineralization and uptake of (15)N were higher in plants performing HL than in plants without HL. Soils in the upper layer were significantly wetter in the HL treatment than in the no-HL treatment. Decomposition rates were similar in the W and HL treatments and lower in no-HL. On average, the concentration of NH(4)(+)-N in ingrowth cores was highest in the W treatment, and NO(3)(-)-N concentrations were highest in the no-HL treatment, with HL having intermediate values for both, suggesting differential mineralization of organic N among treatments. Aboveground biomass, leaf (15)N contents and the (15)N uptake in aboveground tissues were higher in W and HL than in no-HL, indicating higher nutrient uptake and improved N status of plants performing HL. However, there were no differences in total root nitrogen content or (15)N uptake by roots, indicating that HL affected plant allocation of acquired N to photosynthetic tissues. Our evidence for the role of HL in organic matter decomposition and nutrient cycling suggests that HL could have positive effects on plant nutrient dynamics and nutrient turnover.

  10. NITROGEN DEPOSITION AND ORGANIC MATTER MANIPULATIONS AFFECT GROSS AND NET NITROGEN TRANSFORMATIONS IN TWO TEMPERATE FORESTS SOILS

    Science.gov (United States)

    Soil nitrogen transformations are intricately linked to carbon transformations. We utilized two existing organic matter manipulation sites in western Oregon, USA and Hungary to investigate these linkages. Our questions were: 1) Does the quantity and quality of organic matter af...

  11. Modeling organic nitrogen conversions in activated sludge bioreactors.

    Science.gov (United States)

    Makinia, Jacek; Pagilla, Krishna; Czerwionka, Krzysztof; Stensel, H David

    2011-01-01

    For biological nutrient removal (BNR) systems designed to maximize nitrogen removal, the effluent total nitrogen (TN) concentration may range from 2.0 to 4.0 g N/m(3) with about 25-50% in the form of organic nitrogen (ON). In this study, current approaches to modeling organic N conversions (separate processes vs. constant contents of organic fractions) were compared. A new conceptual model of ON conversions was developed and combined with Activated Sludge Model No. 2d (ASM2d). The model addresses a new insight into the processes of ammonification, biomass decay and hydrolysis of particulate and colloidal ON (PON and CON, respectively). Three major ON fractions incorporated are defined as dissolved (DON) (model parameter set, the behaviors of both inorganic N forms (NH4-N, NOX-N) and ON forms (DON, CON) in the batch experiments were predicted. The challenges to accurately simulate and predict effluent ON levels from BNR systems are due to analytical methods of direct ON measurement (replacing TKN) and lack of large enough database (in-process measurements, dynamic variations of the ON concentrations) which can be used to determine parameter value ranges.

  12. Sources of Nitrogen for Winter Wheat in Organic Cropping Systems

    DEFF Research Database (Denmark)

    Petersen, Søren O; Schjønning, Per; Olesen, Jørgen E;

    2013-01-01

    In organic cropping systems, legumes, cover crops (CC), residue incorporation, and manure application are used to maintain soil fertility, but the contributions of these management practices to soil nitrogen (N) supply remain obscure. We examined potential sources of N for winter wheat (Triticum...... explained 76 and 82% of the variation in grain N yields in organic cropping systems in 2007 and 2008, showing significant effects of, respectively, topsoil N, depth of A horizon, cumulated inputs of N, and N applied to winter wheat in manure. Thus, soil properties and past and current management all...... aestivum L.) in four experimental cropping systems established in 1997 on three soil types. Three of the four systems were under organic management. Topsoil N, depth of the A horizon, and cumulated inputs of N since 1997 were determined at plot level. Labile soil N pools [mineral N, potentially...

  13. Long-term effect of tillage, nitrogen fertilization and cover crops on soil organic carbon and total nitrogen content

    OpenAIRE

    2011-01-01

    Metadata only record No-till practices, in conjunction with cover crops and nitrogen fertilization, have been shown to augment soil organic carbon content and total nitrogen content. However, interactions between these components in a no-till system are not well-known. This study offers a long-term (1993-2008) comparative analysis of conventional versus no-till practices as well as a some insight regarding the synergies between no-till, nitrogen fertilization, and cover crops. Maize, wheat...

  14. Mathematical modeling of wastewater-derived biodegradable dissolved organic nitrogen.

    Science.gov (United States)

    Simsek, Halis

    2016-11-01

    Wastewater-derived dissolved organic nitrogen (DON) typically constitutes the majority of total dissolved nitrogen (TDN) discharged to surface waters from advanced wastewater treatment plants (WWTPs). When considering the stringent regulations on nitrogen discharge limits in sensitive receiving waters, DON becomes problematic and needs to be reduced. Biodegradable DON (BDON) is a portion of DON that is biologically degradable by bacteria when the optimum environmental conditions are met. BDON in a two-stage trickling filter WWTP was estimated using artificial intelligence techniques, such as adaptive neuro-fuzzy inference systems, multilayer perceptron, radial basis neural networks (RBNN), and generalized regression neural networks. Nitrite, nitrate, ammonium, TDN, and DON data were used as input neurons. Wastewater samples were collected from four different locations in the plant. Model performances were evaluated using root mean square error, mean absolute error, mean bias error, and coefficient of determination statistics. Modeling results showed that the R(2) values were higher than 0.85 in all four models for all wastewater samples, except only R(2) in the final effluent sample for RBNN modeling was low (0.52). Overall, it was found that all four computing techniques could be employed successfully to predict BDON.

  15. Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2010-11-01

    Full Text Available Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON and organic carbon (OC as well as isotopic ratios of total nitrogen (TN and total carbon (TC. Increased concentrations of methanesulfonic acid (MSA and diethylammonium (DEA+ at 40–44° N and subtropical regions (10–20° N together with averaged satellite chlorophyll a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C increased from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC ratios showed positive correlations with local wind speeds, suggesting that sea-to-air emissions of ON via sea spray significantly contributes to marine organic aerosols over the

  16. Latitudinal distributions of organic nitrogen and organic carbon in marine aerosols over the western North Pacific

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2011-04-01

    Full Text Available Marine aerosol samples were collected over the western North Pacific along the latitudinal transect from 44° N to 10° N in late summer 2008 for measurements of organic nitrogen (ON and organic carbon (OC as well as isotopic ratios of total nitrogen (TN and total carbon (TC. Increased concentrations of methanesulfonic acid (MSA and diethylammonium (DEA+ at 40–44° N and subtropical regions (10–20° N together with averaged satellite chlorophyll-a data and 5-day back trajectories suggest a significant influence of marine biological activities on aerosols in these regions. ON exhibited increased concentrations up to 260 ngN m−3 in these marine biologically influenced aerosols. Water-insoluble organic nitrogen (WION was found to be the most abundant nitrogen in the aerosols, accounting for 55 ± 16% of total aerosol nitrogen. In particular, the average WION/ON ratio was as high as 0.93 ± 0.07 at 40–44° N. These results suggest that marine biological sources significantly contributed to ON, a majority of which is composed of water-insoluble fractions in the study region. Analysis of the stable carbon isotopic ratios (δ13C indicated that, on average, marine-derived carbon accounted for ~88 ± 12% of total carbon in the aerosols. In addition, the δ13C showed higher values (from −22 to −20‰ when ON/OC ratios increased from 0.15 to 0.35 in marine biologically influenced aerosols. These results clearly show that organic nitrogen is enriched in organic aerosols originated from an oceanic region with high biological productivity, indicating a preferential transfer of nitrogen-containing organic compounds from the sea surface to the marine atmosphere. Both WION concentrations and WION/water-insoluble organic carbon (WIOC ratios tended to increase with increasing local wind speeds, indicating that sea-to-air emissions of ON via sea spray contribute significantly to the marine organic

  17. Organic nitrogen uptake is a significant contributor to nitrogen economy of subtropical epiphytic bryophytes

    Science.gov (United States)

    Song, Liang; Lu, Hua-Zheng; Xu, Xing-Liang; Li, Su; Shi, Xian-Meng; Chen, Xi; Wu, Yi; Huang, Jun-Biao; Chen, Quan; Liu, Shuai; Wu, Chuan-Sheng; Liu, Wen-Yao

    2016-07-01

    Without any root contact with the soil, epiphytic bryophytes must experience and explore poor, patchy, and heterogeneous habitats; while, the nitrogen (N) uptake and use strategies of these organisms remain uncharacterized, which obscures their roles in the N cycle. To investigate the N sources, N preferences, and responses to enhanced N deposition in epiphytic bryophytes, we carried out an in situ manipulation experiment via the 15N labelling technique in an Asian cloud forest. Epiphytic bryophytes obtained more N from air deposition than from the bark, but the contribution of N from the bark was non-negligible. Glycine accounted for 28.4% to 44.5% of the total N in bryophyte tissue, which implies that organic N might serve as an important N source. Increased N deposition increased the total N uptake, but did not alter the N preference of the epiphytic bryophytes. This study provides sound evidence that epiphytic bryophytes could take up N from the bark and wet deposition in both organic and inorganic N forms. It is thus important to consider organic N and bark N sources, which were usually neglected, when estimating the role of epiphytic bryophytes in N cycling and the impacts of N deposition on epiphytic bryophytes in cloud forests.

  18. Identification of nitrogenous organic species in Titan aerosols analogs: Nitrogen fixation routes in early atmospheres

    Science.gov (United States)

    He, Chao; Smith, Mark A.

    2013-09-01

    Titan, an icy world surrounded by auburn organic haze, is considered as one of the best targets for studying abiotic planetary organic chemistry. In spite of a great many efforts being made, the chemistry in Titan’s atmosphere and its resulting chemical structures are still not fully understood. In our previous work, we have investigated the structure of Titan aerosols analogs (tholin) by NMR and identified hexamethylenetetramine as a dominant small molecule in Titan tholin. Here we report a more complete and definitive structural investigation of the small molecule inventory in Titan tholin. We identified several nitrogenous organic molecules including cyanamide, guanidine, 2-cyanoguanidine, melamine, N‧-cyanoformamidine and 1,2,4-triazole in Titan tholin by using NMR and GC-MS and standard sample comparison. The structural characteristics of these molecules suggest a possible formation pathway from the reaction of HCN and NH3, both of which are known to exist in appreciable density in the atmosphere and were tentatively detected by the Huygens probe.

  19. Particulate organic carbon and nitrogen export from major Arctic rivers

    Science.gov (United States)

    McClelland, J. W.; Holmes, R. M.; Peterson, B. J.; Raymond, P. A.; Striegl, R. G.; Zhulidov, A. V.; Zimov, S. A.; Zimov, N.; Tank, S. E.; Spencer, R. G. M.; Staples, R.; Gurtovaya, T. Y.; Griffin, C. G.

    2016-05-01

    Northern rivers connect a land area of approximately 20.5 million km2 to the Arctic Ocean and surrounding seas. These rivers account for ~10% of global river discharge and transport massive quantities of dissolved and particulate materials that reflect watershed sources and impact biogeochemical cycling in the ocean. In this paper, multiyear data sets from a coordinated sampling program are used to characterize particulate organic carbon (POC) and particulate nitrogen (PN) export from the six largest rivers within the pan-Arctic watershed (Yenisey, Lena, Ob', Mackenzie, Yukon, Kolyma). Together, these rivers export an average of 3055 × 109 g of POC and 368 × 109 g of PN each year. Scaled up to the pan-Arctic watershed as a whole, fluvial export estimates increase to 5767 × 109 g and 695 × 109 g of POC and PN per year, respectively. POC export is substantially lower than dissolved organic carbon export by these rivers, whereas PN export is roughly equal to dissolved nitrogen export. Seasonal patterns in concentrations and source/composition indicators (C:N, δ13C, Δ14C, δ15N) are broadly similar among rivers, but distinct regional differences are also evident. For example, average radiocarbon ages of POC range from ~2000 (Ob') to ~5500 (Mackenzie) years before present. Rapid changes within the Arctic system as a consequence of global warming make it challenging to establish a contemporary baseline of fluvial export, but the results presented in this paper capture variability and quantify average conditions for nearly a decade at the beginning of the 21st century.

  20. Modeling the effects of organic nitrogen uptake by plants on the carbon cycling of boreal ecosystems

    Directory of Open Access Journals (Sweden)

    Q. Zhu

    2013-08-01

    Full Text Available Boreal forest and tundra are the major ecosystems in the northern high latitudes in which a large amount of carbon is stored. These ecosystems are nitrogen-limited due to slow mineralization rate of the soil organic nitrogen. Recently, abundant field studies have found that organic nitrogen is another important nitrogen supply for boreal ecosystems. In this study, we incorporated a mechanism that allowed boreal plants to uptake small molecular amino acids into a process-based biogeochemical model, the Terrestrial Ecosystem Model (TEM, to evaluate the impact of organic nitrogen uptake on ecosystem carbon cycling. The new version of the model was evaluated at both boreal forest and tundra sites. We found that the modeled organic nitrogen uptake accounted for 36–87% of total nitrogen uptake by plants in tundra ecosystems and 26–50% for boreal forests, suggesting that tundra ecosystem might have more relied on the organic form of nitrogen than boreal forests. The simulated monthly gross ecosystem production (GPP and net ecosystem production (NEP tended to be larger with the new version of the model since the plant uptake of organic nitrogen alleviated the soil nitrogen limitation especially during the growing season. The sensitivity study indicated that the most important factors controlling the plant uptake of organic nitrogen were the maximum root uptake rate (Imax and the radius of the root (r0 in our model. The model uncertainty due to uncertain parameters associated with organic nitrogen uptake at tundra ecosystem was larger than at boreal forest ecosystems. This study suggests that considering the organic nitrogen uptake by plants is important to boreal ecosystem carbon modeling.

  1. ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMEN

    Directory of Open Access Journals (Sweden)

    MARCELO RIBEIRO VILELA PRADO

    2016-01-01

    Full Text Available The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF and kudzu (Pueraria montana; Agroforestry System 2: coffee (Coffea canephora, marandu palisade grass (Brachiaria brizantha cv. Marandu, “pinho cuiabano” (Parkia multijuga, teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao; Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

  2. Black Nitrogen or Plant-Derived Organic Nitrogen - which Form is More Efficiently Sequestered in Soils?

    Science.gov (United States)

    López-Martín, María; Velasco-Molina, Marta; Knicker, Heike

    2014-05-01

    and approached those of the pots with fresh grass litter supporting the mobilization of black nitrogen and its uptake by plants. Our results point to the suggestion that N in PyOM and humified SOM have comparable biochemical stability. In order to test this hypothesis, a further experiment was set up mixtures of soil and humified 15N grass residues or aged 15N grass char to which fresh PyOM or fresh grass residues, respectively, were added. In addition solid-state 15N NMR spectroscopy was applied to disclose the nature of the sequestered N. REFERENCES Knicker, H., Almendros, G., González-Vila, F.J., Martín, F., Lüdemann, H.-D., 1996. 13C- and 15N-NMR spectroscopic examination of the transformation of organic nitrogen in plant biomass during thermal treatment. Soil Biology and Biochemistry, 28, 1053-1060.

  3. Nitrogen fertilization of coffee: organic compost and Crotalaria juncea L.

    Directory of Open Access Journals (Sweden)

    João Batista Silva Araujo

    2013-12-01

    Full Text Available Information concerning the response of coffee to organic fertilizers is scarce. This study evaluates the effect of different doses of compost and Crotalaria juncea L. on growth, production and nitrogen nutrition of coffee trees. The treatments consisted of compost at rates of 25, 50, 75 and 100% of the recommended fertilization, with or without the aerial part of C. juncea. C. juncea was grown with NH4-N (2% 15N and applied to coffee. The use of C. juncea increased growth in height and diameter of the coffee canopy. In the first year, the percentage of N derived from C. juncea reached 8.5% at seven months and 4.1% at fifteen months after fertilization. In the second year, the percentage of N derived from C. juncea reached 17.9% N at the early harvest, five months after fertilization. Increased rates of compost increased pH , P , K , Ca , Mg , sum of bases , effective CEC, base saturation and organic matter and reduced potential acidity. 15N allowed the identification of the N contribution from C. juncea with percentage of leaf N derived from Crotalaria juncea from 9.2 to 17.9%.

  4. Soil organic nitrogen mineralization across a global latitudinal gradient

    Science.gov (United States)

    Jones, D. L.; Kielland, K.; Sinclair, F. L.; Dahlgren, R. A.; Newsham, K. K.; Farrar, J. F.; Murphy, D. V.

    2009-03-01

    Understanding and accurately predicting the fate of carbon and nitrogen in the terrestrial biosphere remains a central goal in ecosystem science. Amino acids represent a key pool of C and N in soil, and their availability to plants and microorganisms has been implicated as a major driver in regulating ecosystem functioning. Because of potential differences in biological diversity and litter quality, it has been thought that soils from different latitudes and plant communities may possess intrinsically different capacities to perform key functions such as the turnover of amino acids. In this study we measured the soil solution concentration and microbial mineralization of amino acids in soils collected from 40 latitudinal points from the Arctic through to Antarctica. Our results showed that soil solution amino acid concentrations were relatively similar between sites and not strongly related to latitude. In addition, when constraints of temperature and moisture were removed, we demonstrate that soils worldwide possess a similar innate capacity to rapidly mineralize amino acids. Similarly, we show that the internal partitioning of amino acid-C into catabolic and anabolic processes is conservative in microbial communities and independent of global position. This supports the view that the conversion of high molecular weight (MW) organic matter to low MW compounds is the rate limiting step in organic matter breakdown in most ecosystems.

  5. Biogas production from substrates with high amounts of organic nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Prechtl, S.; Faulstich, M. [ATZ-EVUS Development Center for Process Engineering, Sulzbach-Rosenberg (Germany)

    2004-07-01

    Thermophilic fermentation is a favoured method for treating animal by-products because of its short hydraulic retention time and hygienic features. However, substrates with high organic nitrogen content can create problems in the fermentation process due to the high ammonium concentration produced during anaerobic degradation. More economical and ecological solutions for treating animal by-products are also needed to address concerns of the Bovine Spongiform Encephalopathy (BSE) crisis. This study considered a recycling concept based on the Thermal Pressure Hydrolysis (TPH) process with subsequent anaerobic digestion. A heat exchange system was also developed. The sterilization in the TPH reactor guarantees complete disinfection. The study examined the reactor temperature, pH-value, hydraulic retention time, organic loading rate and degradation performance. The amount of volatile fatty acids in the effluent of the anaerobic reactor suggests good biological degradation. A combined heat and power station with an electrical efficiency of 38 per cent made it possible to produce up to 780 kWh of electricity from 1,000 kg of raw material. 6 refs., 2 tabs., 1 fig.

  6. Organic and inorganic nitrogen dynamics in soil - advanced Ntrace approach

    Science.gov (United States)

    Andresen, Louise C.; Björsne, Anna-Karin; Bodé, Samuel; Klemedtsson, Leif; Boeckx, Pascal; Rütting, Tobias

    2016-04-01

    Depolymerization of soil organic nitrogen (SON) into monomers (e.g. amino acids) is currently thought to be the rate limiting step for the terrestrial nitrogen (N) cycle. The production of free amino acids (AA) is followed by AA mineralization to ammonium, which is an important fraction of the total N mineralization. Accurate assessment of depolymerization and AA mineralization rate is important for a better understanding of the rate limiting steps. Recent developments in the 15N pool dilution techniques, based on 15N labelling of AA's, allow quantifying gross rates of SON depolymerization and AA mineralization (Wanek et al., 2010; Andersen et al., 2015) in addition to gross N mineralization. However, it is well known that the 15N pool dilution approach has limitations; in particular that gross rates of consumption processes (e.g. AA mineralization) are overestimated. This has consequences for evaluating the rate limiting step of the N cycle, as well as for estimating the nitrogen use efficiency (NUE). Here we present a novel 15N tracing approach, which combines 15N-AA labelling with an advanced version of the 15N tracing model Ntrace (Müller et al., 2007) explicitly accounting for AA turnover in soil. This approach (1) provides a more robust quantification of gross depolymerization and AA mineralization and (2) suggests a more realistic estimate for the microbial NUE of amino acids. Advantages of the new 15N tracing approach will be discussed and further improvements will be identified. References: Andresen, L.C., Bodé, S., Tietema, A., Boeckx, P., and Rütting, T.: Amino acid and N mineralization dynamics in heathland soil after long-term warming and repetitive drought, SOIL, 1, 341-349, 2015. Müller, C., Rütting, T., Kattge, J., Laughlin, R. J., and Stevens, R. J.: Estimation of parameters in complex 15N tracing models via Monte Carlo sampling, Soil Biology & Biochemistry, 39, 715-726, 2007. Wanek, W., Mooshammer, M., Blöchl, A., Hanreich, A., and Richter

  7. Atmospheric Deposition of Soluble Organic Nitrogen due to Biomass Burning

    Science.gov (United States)

    Ito, A.; Lin, G.; Penner, J. E.

    2014-12-01

    Atmospheric deposition of reactive nitrogen (N) species from large fires may contribute to enrichment of nutrients in aquatic ecosystems. Here we use an atmospheric chemistry transport model to investigate the supply of soluble organic nitrogen (ON) from open biomass burning to the ocean. The model results show that the annual deposition rate of soluble ON to the oceans is increased globally by 13% with the increase being particularly notable over the coastal water downwind from the source regions. The estimated deposition of soluble ON due to haze events from the secondary formation is more than half of that from the primary sources. We examine the secondary formation of particulate C-N compounds (e.g., imidazole) from the reactions of glyoxal and methylglyoxal with atmospheric ammonium in wet aerosols and upon cloud evaporation. These ON sources result in a significant contribution to the open ocean, suggesting that atmospheric processing in aqueous phase may have a large effect. We compare the soluble ON concentration in aerosols with and without open biomass burning as a case study in Singapore. The model results demonstrate that the soluble ON concentration in aerosols is episodically enriched during the fire events, compared to the without smoke simulations. However, the model results show that the daily soluble ON concentration can be also enhanced in the without smoke simulations during the same period, compared to the monthly averages. This indicates that care should be taken when using in-situ observations to constrain the soluble ON source strength from biomass burning. More accurate quantification of the soluble ON burdens with no smoke sources is therefore needed to assess the effect of biomass burning on bioavailable ON input to the oceans.

  8. Distribution of various forms of organic nitrogen in a lignite macromolecule

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V.V.; Proskuryakov, V.A.; Polovetskaya, O.S.; Shavyrina, O.A.; Ryl' tsova, S.V. [Lev Tolstoi State Pedalogical University, Tula (Russian Federation)

    2001-07-01

    The chemical composition of organic bases from tars of stepwise semicoking of lignite was studied. The features of distribution of organic nitrogen in a coal macromolecule and the most probable pathways of thermal degradation of the nitrogen-containing fragments were examined.

  9. Bioavailable and biodegradable dissolved organic nitrogen in activated sludge and trickling filter wastewater treatment plants

    Science.gov (United States)

    A study was carried out to understand the fate of biodegradable dissolved organic nitrogen (BDON) and bioavailable dissolved organic nitrogen (ABDON) along the treatment trains of a wastewater treatment facility (WWTF) equipped with an activated sludge (AS) system and a WWTF equipped with a two-stag...

  10. Nitrogen

    Science.gov (United States)

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  11. Organic nitrogen storage in mineral soil: Implications for policy and management.

    Science.gov (United States)

    Bingham, Andrew H; Cotrufo, M Francesca

    2016-05-01

    Nitrogen is one of the most important ecosystem nutrients and often its availability limits net primary production as well as stabilization of soil organic matter. The long-term storage of nitrogen-containing organic matter in soils was classically attributed to chemical complexity of plant and microbial residues that retarded microbial degradation. Recent advances have revised this framework, with the understanding that persistent soil organic matter consists largely of chemically labile, microbially processed organic compounds. Chemical bonding to minerals and physical protection in aggregates are more important to long-term (i.e., centuries to millennia) preservation of these organic compounds that contain the bulk of soil nitrogen rather than molecular complexity, with the exception of nitrogen in pyrogenic organic matter. This review examines for the first time the factors and mechanisms at each stage of movement into long-term storage that influence the sequestration of organic nitrogen in the mineral soil of natural temperate ecosystems. Because the factors which govern persistence are different under this newly accepted paradigm we examine the policy and management implications that are altered, such as critical load considerations, nitrogen saturation and mitigation consequences. Finally, it emphasizes how essential it is for this important but underappreciated pool to be better quantified and incorporated into policy and management decisions, especially given the lack of evidence for many soils having a finite capacity to sequester nitrogen.

  12. Parametrization of organic nitrogen mineralization models in soil treated with swine raising wastewater

    Directory of Open Access Journals (Sweden)

    Demétrius David da Silva

    2010-08-01

    Full Text Available Little is known about the mineralization dynamic of organic nitrogen contained in swine manure, so models need to be adjusted for its prediction. The objective of the present study was to parameterize and assess models of organic nitrogen mineralization in soil treated with swine raising wastewater (SRW at different temperatures and water contents. Samples of 57.3 cm3 of dystrophic Red-Yellow Latosol were mixed with SRW at the application dose of 400 kg ha-1 nitrogen, placed in plastic cups and incubated at four different temperatures (15, 20, 25 and 35°C and water contents corresponding to tensions of 10, 30, 200 and 1500 kPa. Samples were removed from the incubated soil after 3, 6, 12, 24, 48 and 96 days to quantify the ammonium and nitrate concentrations. The parameters of the soil organic nitrogen mineralization models were determined from the organic nitrogen mineralization values obtained over the different incubation periods. The value of the potentially mineralizable nitrogen (N0 in soil with application of SRW was superior that of the soil without application of SRW. The mineralization constant (k in soil with application of SRW was always superior that of the soil without application of SRW. There was a tendency for the simple exponential model to underestimate the values of the mineralized nitrogen concentration. In most of the situations the potential model was more efficient than the simple exponential model to predict the mineralization of the organic nitrogen.

  13. Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

    NARCIS (Netherlands)

    van Engeland, T.; Soetaert, K.; Knuijt, K.; Laane, R.W.P.M.; Middelburg, J.J.

    2010-01-01

    Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robu

  14. Determination of the Fate of Dissolved Organic Nitrogen in the Three Wastewater Treatment Plants, Jordan

    Science.gov (United States)

    Wedyan, Mohammed; Al Harahsheh, Ahmed; Qnaisb, Esam

    2016-01-01

    This research aimed to assess the composition of total dissolved nitrogen (TDN) species, particularly dissolved organic nitrogen (DON), over the traditional wastewater treatment operations in three biological nutrient removal (BNR) wastewater treatment plants (WWTPs) in Jordan. It had been found that the DON percentage was up to 30% of TDN within…

  15. Leaching of dissolved organic and inorganic nitrogen from legume-based grasslands

    DEFF Research Database (Denmark)

    Kusliene, Gedrime; Eriksen, Jørgen; Rasmussen, Jim

    2015-01-01

    Leaching of dissolved inorganic nitrogen (DIN) and dissolved organic nitrogen (DON) is a considerable loss pathway in grassland soils. We investigated the white clover (Trifolium repens) contribution to N transport and temporal N dynamics under a pure stand of white clover and white clover...

  16. Dissolved organic nitrogen dominates in European bogs under increasing atmospheric N deposition

    NARCIS (Netherlands)

    Bragazza, L.; Limpens, J.

    2004-01-01

    To assess the effects of increased atmospheric N input on N availability in ombrotrophic peatlands, the relative concentrations of dissolved organic nitrogen (DON) to dissolved inorganic nitrogen (DIN) were measured in bog waters along a natural gradient of atmospheric N deposition. Six European bog

  17. Nitrogen Containing Organic Compounds and Oligomers in Secondary Organic Aerosol Formed by Photooxidation of Isoprene

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tran B.; Laskin, Julia; Laskin, Alexander; Nizkorodov, Serguei

    2011-07-06

    Electrospray ionization high-resolution mass spectrometry (ESI HR-MS) was used to probe molecular structures of oligomers in secondary organic aerosol (SOA) generated in laboratory experiments on isoprene photooxidation at low- and high-NOx conditions. Up to 80-90% of the observed products are oligomers and up to 33% are nitrogen-containing organic compounds (NOC). We observe oligomers with up to 8 monomer units in length. Tandem mass spectrometry (MSn) confirms NOC compounds are organic nitrates and elucidates plausible chemical building blocks contributing to oligomer formation. Most organic nitrates are comprised of methylglyceric acid units. Other important multifunctional C2-C5 monomer units are identified including methylglyoxal, hydroxyacetone, hydroxyacetic acid, glycolaldehyde, and 2-methyltetrols. The majority of the NOC oligomers contain only one nitrate moiety resulting in a low average N:C ratio of 0.019. Average O:C ratios of the detected SOA compounds are 0.54 under the low-NOx conditions and 0.83 under the high-NOx conditions. Our results underscore the importance of isoprene photooxidation as a source of NOC in organic particulate matter.

  18. Studies on organic carbon, nitrogen and phosphorous in the sediments of Mandovi Estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nasnolkar, C.M.; Shirodkar, P.V.; Singbal, S.Y.S.

    Sediment organic carbon, total nitrogen, total phosphorous and hydrography of the overlying waters of the estuarine region in Mandovi Estuary, Goa, India have been studied. The relationship of carbon and nutrients with sediment characteristics...

  19. Nitrogen loss from unpolluted South American forests mainly via dissolved organic compounds

    Science.gov (United States)

    Perakis, Steven S.; Hedin, Lars O.

    2002-01-01

    Conceptual and numerical models of nitrogen cycling in temperate forests assume that nitrogen is lost from these ecosystems predominantly by way of inorganic forms, such as nitrate and ammonium ions. Of these, nitrate is thought to be particularly mobile, being responsible for nitrogen loss to deep soil and stream waters. But human activities-such as fossil fuel combustion, fertilizer production and land-use change-have substantially altered the nitrogen cycle over large regions, making it difficult to separate natural aspects of nitrogen cycling from those induced by human perturbations. Here we report stream chemistry data from 100 unpolluted primary forests in temperate South America. Although the sites exhibit a broad range of environmental factors that influence ecosystem nutrient cycles (such as climate, parent material, time of ecosystem development, topography and biotic diversity), we observed a remarkably consistent pattern of nitrogen loss across all forests. In contrast to findings from forests in polluted regions, streamwater nitrate concentrations are exceedingly low, such that nitrate to ammonium ratios were less than unity, and dissolved organic nitrogen is responsible for the majority of nitrogen losses from these forests. We therefore suggest that organic nitrogen losses should be considered in models of forest nutrient cycling, which could help to explain observations of nutrient limitation in temperate forest ecosystems.

  20. Nitrogen removal efficiency of iron-carbon micro-electrolysis system treating high nitrate nitrogen organic pharmaceutical wastewater

    Institute of Scientific and Technical Information of China (English)

    周健; 段送华; 陈垚; 胡斌

    2009-01-01

    The nitrate nitrogen removal efficiency of iron-carbon micro-electrolysis system was discussed in treating pharmaceutical wastewater with high nitrogen and refractory organic concentration. The results show that the granularity of fillings,pH,volume ratios of iron-carbon and gas-water,and HRT. have significant effects on the nitrogen removal efficiency of iron-carbon micro-electrolysis system. The iron-carbon micro-electrolysis system has a good removal efficiency of pharmaceutical wastewater with high nitrogen and refractory organic concentration when the influent TN,NH4+-N,NO3--N and BOD5/CODCr are 823 mg/L,30 mg/L,793 mg/L and 0.1,respectively,at the granularity of iron and carbon 0.425 mm,pH 3,iron-carbon ratio 3,gas-water ratio 5,HRT 1.5 h,and the removal rates of TN,NH4+-N and NO3--N achieve 51.5%,70% and 50.94%,respectively.

  1. Characterizing the transformation and transfer of nitrogen during the aerobic treatment of organic wastes and digestates

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Yang, E-mail: yang.zeng@irstea.fr [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France); Universite Europeenne de Bretagne, F-35000 Rennes (France); Guardia, Amaury de; Daumoin, Mylene; Benoist, Jean-Claude [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Ammonia emissions varied depending on the nature of wastes and the treatment conditions. Black-Right-Pointing-Pointer Nitrogen losses resulted from ammonia emissions and nitrification-denitrification. Black-Right-Pointing-Pointer Ammonification can be estimated from biodegradable carbon and carbon/nitrogen ratio. Black-Right-Pointing-Pointer Ammonification was the main process contributing to N losses. Black-Right-Pointing-Pointer Nitrification rate was negatively correlated to stripping rate of ammonia nitrogen. - Abstract: The transformation and transfer of nitrogen during the aerobic treatment of seven wastes were studied in ventilated air-tight 10-L reactors at 35 Degree-Sign C. Studied wastes included distinct types of organic wastes and their digestates. Ammonia emissions varied depending on the kind of waste and treatment conditions. These emissions accounted for 2-43% of the initial nitrogen. Total nitrogen losses, which resulted mainly from ammonia emissions and nitrification-denitrification, accounted for 1-76% of the initial nitrogen. Ammonification was the main process responsible for nitrogen losses. An equation which allows estimating the ammonification flow of each type of waste according to its biodegradable carbon and carbon/nitrogen ratio was proposed. As a consequence of the lower contribution of storage and leachate rates, stripping and nitrification rates of ammonia nitrogen were negatively correlated. This observation suggests the possibility of promotingnitrification in order to reduce ammonia emissions.

  2. Organic nitrogen deposition on land and coastal environments: a review of methods and data

    Science.gov (United States)

    Cornell, S. E.; Jickells, T. D.; Cape, J. N.; Rowland, A. P.; Duce, R. A.

    Despite over a century of published reports of dissolved organic nitrogen (DON) in precipitation, its implications are still being appraised. The number of studies focusing on atmospheric organic nitrogen deposition has increased steadily in recent years, but comparatively little has been done to draw together this disparate knowledge. This is partly a consequence of valid concerns about the comparability of analysis and sampling methodologies. Given the current global trends in anthropogenic nitrogen fixation, an improved qualitative and quantitative understanding of the organic nitrogen component is needed to complement the well-established knowledge base pertaining to nitrate and ammonium deposition. This global review confirms the quantitative importance of bulk DON in precipitation. This cumulative data set also helps to resolve some of the uncertainty that arises from the generally locally and temporally limited scale of the individual studies. Because of analytical and procedural changes in recent decades, assessments are made of the comparability of the data sets; caution is needed in comparisons of individual studies, but the overall trends in the compiled set are more robust. Despite the large number of reports considered, evidence for long-term temporal changes in rainwater organic nitrogen concentrations is ambiguous. With regard to sources, it is likely that some of the organic material observed is not locally generated, but undergoes extensive or long-range atmospheric transport. The compiled data set shows a land-to-sea gradient in organic nitrogen concentration. Possible precursors, reported data on the most likely component groups, and potential source mechanisms are also outlined.

  3. Carbon and nitrogen stocks and nitrogen mineralization in organically managed soils amended with composted manures.

    Science.gov (United States)

    Romanyà, Joan; Arco, Noèlia; Solà-Morales, Ignasi; Armengot, Laura; Sans, Francesc Xavier

    2012-01-01

    The use of composted manures and of legumes in crop rotations may control the quality and quantity of soil organic matter and may affect nutrient retention and recycling. We studied soil organic C and N stocks and N mineralization in organically and conventionally managed dryland arable soils. We selected 13 extensive organic fields managed organically for 10 yr or more as well as adjacent fields managed conventionally. Organic farmers applied composted manures ranging from 0 to 1380 kg C ha yr and incorporated legumes in crop rotations. In contrast, conventional farmers applied fresh manures combined with slurries and/or mineral fertilizers ranging from 200 to 1900 kg C ha yr and practiced a cereal monoculture. Despite the fact that the application of organic C was similar in both farming systems, organically managed soils showed higher C and similar N content and lower bulk density than conventionally managed soils. Moreover, organic C stocks responded to the inputs of organic C in manures and to the presence of legumes only in organically managed soils. In contrast, stocks of organic N increased with the inputs of N or C in both farming systems. In organically managed soils, organic N stocks were less mineralizable than in conventional soils. However, N mineralization in organic soils was sensitive to the N fixation rates of legumes and to application rate and C/N ratio of the organic fertilizers.

  4. Improved speciation of dissolved organic nitrogen in natural waters: amide hydrolysis with fluorescence derivatization

    Institute of Scientific and Technical Information of China (English)

    Ryan L.Firnmen; Tamara D.Trouts; Daniel D.Richter Jr.; Dharni Vasudevan

    2008-01-01

    The objective of this study was to improve primary-amine nitrogen (1°-N) quantification in dissolved organic matter (DOM)originating from natural waters where inorganic forms of N, which may cause analytical interference, are commonly encountered.Efforts were targeted at elucidating organic-N structural criteria influencing the response of organic amines to known colorimetric andfluorescent reagents and exploring the use of divalent metal-assisted amide hydrolysis in combination with fluorescence analyses.We found that reaction of o-phthaldialdehyde (OPA) with primary amines is significantly influenced by steric factors, whereasfluorescamine (FLU) lacks sensitivity to steric factors and allows for the detection of a larger suite of organic amines, includingdi- and tri-peptides and sterically hindered 1°-N. Due to the near quantitative recovery of dissolved peptides with the FLU reagent andlack of analytical response to inorganic nitrogen, we proposed that FLU be utilized for the quantification of primary amine nitrogen.In exploring the application of divalent metal promoted peptide hydrolysis to the analysis of organic forms of nitrogen in DOM, wefound that Zn(Ⅱ) reaction increased the total fraction of organic-N detectable by both OPA and FLU reagents. Zn-hydrolysis improvedrecovery of organic-N in natural waters from<5% to 35%. The above method, coupled with standard inorganic-N analyses, allows forenhanced resolution of dissolved organic nitrogen (DON) speciation in natural waters.

  5. Cycling of organic and mineral nitrogen along a latitudinal transect in Western Siberia

    Science.gov (United States)

    Wild, Birgit; Schnecker, Jörg; Knoltsch, Anna; Takriti, Mounir; Mooshammer, Maria; Lashchinskiy, Nikolay; Richter, Andreas

    2014-05-01

    The availability of nitrogen in soils is constrained by the breakdown of N-rich organic polymers, in particular proteins. Oligo-peptides and amino acids derived from protein depolymerization are subsequently taken up by soil microorganisms, and, if nitrogen availability exceeds nitrogen demand, excess nitrogen will be released as ammonium ("nitrogen mineralization"), which then can be used as a substrate for nitrification. We here report on the dynamics of organic and mineral nitrogen along a latitudinal transect in Western Siberia (67°-54°N), from the tundra (tree growth restricted by low temperature), over three sites of coniferous forest (taiga) and two sites of forest steppe (deciduous forest and meadow), to steppe (tree growth restricted by low precipitation). For each of the seven sites, we sampled three soil horizons, and applied 15N pool dilution assays to determine gross rates of protein depolymerization, nitrogen mineralization, and nitrification. All nitrogen transformation rates were significantly correlated with carbon and nitrogen content, as well as microbial biomass, and decreased with depth from organic topsoil over mineral topsoil to mineral subsoil. The decrease with depth was stronger for protein depolymerization than for nitrogen mineralization and nitrification, i.e., ratios of mineralization or nitrification over protein depolymerization increased with depth. As both mineralization and nitrification depend on the degree of microbial nitrogen limitation, our findings suggest that microbial nitrogen limitation decreased with soil depth, possibly due to increasing energy limitation of microorganisms. Within the organic topsoil, protein depolymerization rates showed large variability between ecosystems, reaching the highest values in middle (60°N) and southern taiga (58°N), representing the most productive forests along the transect. We discuss these results with respect to differences of the biomes in climatic conditions, vegetation

  6. Organic nitrogen storage in mineral soil: Implications for policy and management

    Energy Technology Data Exchange (ETDEWEB)

    Bingham, Andrew H., E-mail: drew_bingham@nps.gov [Air Resources Division, National Park Service, P.O. Box 25287, Denver, CO 80225 (United States); Cotrufo, M. Francesca [Department of Soil and Crop Sciences and Natural Resources Ecology Laboratory, Colorado State University, 200 West Lake Street, Fort Collins, CO 80523 (United States)

    2016-05-01

    Nitrogen is one of the most important ecosystem nutrients and often its availability limits net primary production as well as stabilization of soil organic matter. The long-term storage of nitrogen-containing organic matter in soils was classically attributed to chemical complexity of plant and microbial residues that retarded microbial degradation. Recent advances have revised this framework, with the understanding that persistent soil organic matter consists largely of chemically labile, microbially processed organic compounds. Chemical bonding to minerals and physical protection in aggregates are more important to long-term (i.e., centuries to millennia) preservation of these organic compounds that contain the bulk of soil nitrogen rather than molecular complexity, with the exception of nitrogen in pyrogenic organic matter. This review examines for the first time the factors and mechanisms at each stage of movement into long-term storage that influence the sequestration of organic nitrogen in the mineral soil of natural temperate ecosystems. Because the factors which govern persistence are different under this newly accepted paradigm we examine the policy and management implications that are altered, such as critical load considerations, nitrogen saturation and mitigation consequences. Finally, it emphasizes how essential it is for this important but underappreciated pool to be better quantified and incorporated into policy and management decisions, especially given the lack of evidence for many soils having a finite capacity to sequester nitrogen. - Highlights: • We review the current framework for long-term nitrogen stabilization in soils. • We highlight the most important factors according to this framework. • We discuss how these factors may influence management and policy decisions.

  7. Organic Matter Loading Modifies the Microbial Community Responsible for Nitrogen Loss in Estuarine Sediments.

    Science.gov (United States)

    Babbin, Andrew R; Jayakumar, Amal; Ward, Bess B

    2016-04-01

    Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using (15)N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more, and the fraction of nitrogen loss attributed to anammox slightly reduced, by the higher organic matter addition. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community composition as determined using a nirS microarray, indicating that the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.

  8. Nitrogen forms and decomposition of organic carbon in the southern Bohai Sea core sediments

    Institute of Scientific and Technical Information of China (English)

    宋金明; 马红波; 吕晓霞

    2002-01-01

    Study on form characteristics of nitrogen in marine sediments is the primary method to research its biogeochemical cycling and nitrogen form characteristics in core sediments can reflect the process and results of early diagenesis in a certain degree. In this paper, Sequential extraction process in natural grain size was used for studying the existent forms of nitrogen in five core sediments of the southern Bohai Sea for the first time. Nitrogen was divided into two parts - transferable and fixed based on whether it could be extracted by the reagent. Distributions and early diagenesis of transferable nitrogen forms in the southern Bohai Sea were researched integratedly. Results indicate that IEF- N and OSFN are predominant forms in transferable part in the studied core sediments. Contents of different nitrogen forms vary differently with depth, and have different diagenesis process. Decomposition constant of organic nitrogen (ON) and OC are about 15.51 × 10-3a-1and 4.79 × 10-3a-1 respectively, and the decomposition content of biogenic elements C, N, P, Si has the sequence N>P>C>Si. OC/TN (simplified as C/N in the following) ratio is much lower than OC/ON, which indicates that sediment preserves plenty of inorganic nitrogen (IN) and/or fixed nitrogen, and the decrease of OC/ON ratio with depth is due to ON reservation in sediments. Generally, transferable nitrogen accounts for more proportion of TN in the surface layer than in the deep layer of core sediments, whereas, some stable forms of nitrogen can activate and become transferable under appropriate environment, which induces the proportion of transferable nitrogen in TN in the deep layer to be almost the same as that in the surface layer.

  9. Nitrogen and dissolved organic carbon (DOC losses from an artificially drained grassland on organic soils

    Directory of Open Access Journals (Sweden)

    B. Tiemeyer

    2014-02-01

    Full Text Available Nitrate-nitrogen (NO3-N as well as dissolved organic carbon (DOC and nitrogen (DON concentrations and losses were studied for three respectively two years in a small catchment dominated by a degraded peatland used as intensive grassland. Concentrations in the shallow groundwater were spatially and temporally very variable with NO3-N being the most dynamic component (7.3 ± 12.5 mg L–1. Average NO3-N concentrations of 10.3 ± 5.4 mg L–1 in the ditch draining the catchment and annual NO3-N losses of 19, 35 and 26 kg ha–1 confirmed drained peatlands as an important source of diffuse N pollution. The highest NO3-N losses occurred during the wettest year. Resulting from concentrations of 2.4 ± 0.8 mg L–1, DON added further 4.5 to 6.4 kg ha–1 to the N losses and thus formed a relevant component of the total N losses. Ditch DOC concentrations of 24.9 ± 5.9 mg L–1 resulted in DOC losses of 66 kg ha–1 in the wet year 2006/07 and 39 kg ha–1 in the dry year 2007/08. Both DOC and N concentrations were governed by hydrological conditions, but NO3-N reacted much faster and clearer on rising discharge rates than DOC which tended to be higher under dryer conditions. In the third year of the study, the superposition of a very wet summer and land use changes from grassland to arable land in a part of the catchment suggests that under re-wetting conditions with a high groundwater table in summer, NO3-N would diminish quickly, while DOC would remain on a similar level. Further intensification of the land use, on the other hand, would increase N losses to receiving water bodies.

  10. The impact of exogenous N supply on soluble organic nitrogen dynamics and nitrogen balance in a greenhouse vegetable system.

    Science.gov (United States)

    Liang, Bin; Kang, Lingyun; Ren, Tao; Junliang, Li; Chen, Qing; Wang, Jingguo

    2015-05-01

    A long-term greenhouse experiment (2004-2012) was conducted with continuous tomato (Lycopersicum esculentum Mill.) plantings to understand the influence of an exogenous nitrogen supply from irrigation water, chemical fertilizer, or organic amendment on the N balance and soluble organic nitrogen (SON). The results from 16 tomato growing seasons indicated that the application of organic amendment (manure and straw) alone (Or-N) resulted in the same yield as the conventional chemical N with organic amendment (Co-N) and the reduced chemical N with organic amendment (Re-N) treatments. The annual apparent N loss was >1000 and 438 kg N ha(-1) in the Co-N and Re-N treatments, respectively. Over the study period, the SON in the 1.8 m soil profile was 1449 and 1978 kg N ha(-1) in the Re-N and Co-N treatments, respectively, it was 1.7- and 2.3-fold higher than that observed in the Or-N treatment, which indicated that SON increased with the chemical N application. The percentage of SON in the cumulative soluble N (SON plus mineral N) ranged from 28% to 44%, and there were no significant differences across the 0-0.6, 0.6-1.2, and 1.2-1.8 m soil profile, which indicated that the leaching and distribution of SON was similar to those of the mineral N in the 0-1.8 m soil profile. We conclude that the mobility of soluble organic N in the 0-1.8 m of the soil was synchronous with the mineral N under a greenhouse production system, and the risk of soluble organic N leaching increased with inorganic N application rate. Therefore, leaching of SON in the intensive agriculture should not be ignored when evaluating the risk of N leaching.

  11. [Relationship between Fe, Al oxides and stable organic carbon, nitrogen in the yellow-brown soils].

    Science.gov (United States)

    Heng, Li-Sha; Wang, Dai-Zhang; Jiang, Xin; Rao, Wei; Zhang, Wen-Hao; Guo, Chun-Yan; Li, Teng

    2010-11-01

    The stable organic carbon and nitrogen of the different particles were gained by oxidation of 6% NaOCl in the yellow-brown soils. The relationships between the contents of selective extractable Fe/Al and the stable organic carbon/nitrogen were investigated. It shown that amounts of dithionite-citrate-(Fe(d)) and oxalate-(Fe(o)) and pyrophosphate extractable (Fe(p)) were 6-60.8 g x kg(-1) and 0.13-4.8 g x kg(-1) and 0.03-0.47 g x kg(-1) in 2-250 microm particles, respectively; 43.1-170 g x kg(-1) and 5.9-14.0 g x kg(-1) and 0.28-0.78 g x kg(-1) in soils than in arid yellow-brown soils, and that of selective extractable Al are lower in the former than in the latter. Amounts of the stable organic carbon and nitrogen, higher in paddy yellow-brown soils than in arid yellow-brown soils, were 0.93-6.0 g x kg(-1) and 0.05-0.36 g x kg(-1) in 2-250 microm particles, respectively; 6.05-19.3 g x kg(-1) and 0.61-2.1 g x kg(-1) in organic carbon and nitrogen (C(stable)/N(stable)) were 9.50-22.0 in 2-250 microm particles and 7.43-11.54 in organic carbon and nitrogen were 14.3-50.0 and 11.9-55.6 in 2-250 microm particles, respectively; 53.72-88.80 and 40.64-70.0 in soils than in paddy yellow-brown soils. The organic carbon and nitrogen are advantageously conserved in paddy yellow-brown soil. An extremely significant positive correlation of the stable organic carbon and nitrogen with selective extractable Fe/Al is observed. The most amounts between the stable organic carbon and nitrogen and selective extractable Fe/Al appear in clay particles, namely the clay particles could protect the soil organic carbon and nitrogen.

  12. Nitrogen substitution impacts organic-metal interface energetics

    Science.gov (United States)

    Yang, Ao; Franco-Cañellas, Antoni; Sato, Mikio; Wang, Bin; Wang, Rong-Bin; Koike, Harunobu; Salzmann, Ingo; Thakur, Pardeep Kumar; Lee, Tien-Lin; Liu, Lijia; Kera, Satoshi; Gerlach, Alexander; Kanai, Kaname; Fan, Jian; Schreiber, Frank; Duhm, Steffen

    2016-10-01

    We investigated the structural and electronic properties of vacuum sublimed 7,8,15,16-tetraazaterrylene (TAT) thin films on Au(111), Ag(111), and Cu(111) substrates using inverse photoemission spectroscopy, ultraviolet photoelectron spectroscopy (UPS), x-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED), and the x-ray standing wave (XSW) technique. The LEED reveals a flat adsorption geometry of the monolayer TAT on these three substrates, which is in accordance with the XSW results. The molecules are slightly distorted in monolayers on all three substrates with the nitrogen atoms having smaller averaged bonding distances than the carbon atoms. On Ag(111) and Cu(111), chemisorption with a net electron transfer from the substrate to the adsorbate takes place, as evidenced by UPS and XPS. Combining these results, we gain full insight into the correlation between electronic properties and interface geometry.

  13. The influence of land use on soil organic carbon and nitrogen content and redox potential

    DEFF Research Database (Denmark)

    Kusliene, Gedrime

    2010-01-01

    The aim of the research was to evaluate organic matter status in the soil according to the organic carbon content, total and mineral nitrogen amounts, carbon to nitrogen (C:N) ratio and redox potential depending on land usage and plant spieces. Soil samples were taken from the fields under...... different farming systems (conventional and organic) as well as abandoned lands. We choose the plants of two botanical species (Poaceae and Fabaceae) in organic and conventional farming systems as well as abandoned lands. Experimental results show that the best soil organic matter status according...... to the investigated indexes is in the soils of conventional and orgaic farming systems occupied with mixtures of Poaceae and Fabaceae and the worst - in the soils of abandoned Poaceae meadowa. In the abandoned lands, Fabaceae (galega) had better influence on soil organic matter status than Poaceae....

  14. Organic nitrogen in PM2.5 aerosol at a forest site in the Southeast US

    Directory of Open Access Journals (Sweden)

    A. Khlystov

    2009-08-01

    Full Text Available There is growing evidence that organo-nitrogen compounds may constitute a significant fraction of the aerosol nitrogen (N budget. However, very little is known about the abundance and origin of this aerosol fraction. In this study, the concentration of organic nitrogen (ON and major inorganic ions in PM2.5 aerosol were measured at the Duke Forest Research Facility near Chapel Hill, NC, during January and June of 2007. A novel on-line instrument was used, which is based on the Steam Jet Aerosol Collector (SJAC coupled to an on-line total carbon/total nitrogen analyzer and two on-line ion chromatographs. The concentration of ON was determined by tracking the difference in concentrations of total nitrogen and of inorganic nitrogen (determined as the sum of N-ammonium and N-nitrate. The time resolution of the instrument was 30 min with a detection limit for major aerosol components of ~0.1 μg m−3. Nitrogen in organic compounds contributed ~33% on average to the total nitrogen concentration in PM2.5, illustrating the importance of this aerosol component. Absolute concentrations of ON, however, were relatively low (<1.0 μg m−3 with an average of 0.18 μg m−3. The absolute and relative contribution of ON to the total aerosol nitrogen budget was practically the same in January and June. In January, the concentration of ON tended to be higher during the night and early morning, while in June it tended to be higher during the late afternoon and evening. Back-trajectories and correlation with wind direction indicate higher concentrations of ON in continental air than in marine air masses and indicate a variety of potential sources.

  15. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    Science.gov (United States)

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2016-01-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

  16. [Spacial distribution characteristics of soil organic matter and nitrogen in the natural floodplain wetland].

    Science.gov (United States)

    Bai, Junhong; Deng, Wei; Zhang, Yuxia; Wang, Guoping

    2002-03-01

    The spatial distribution characteristics of soil organic matter and nitrogen in the natural floodplain wetland were studied in this paper. The results showed that the vertical distributions of nutrients in floodplain wetland were very similar, and the horizontal distribution of them in surface soil were distinctly different. The highest concentration of nutrients was not in the frequently-flooded floodplain wetland where the concentrations of soil organic matter and total nitrogen were 2.36% and 2605.4 mg/kg, but in the floodplain with a certain flood frequency. The concentrations of soil organic matter in the one-year floodplain wetland and five-year floodplain wetland were 3.70% and 3.92%, respectively; and the concentrations of total nitrogen were 3666.4 mg/kg and 3125.6 mg/kg, respectively. The ratios of carbon and nitrogen were relatively low. All the factors such as cycling of dry and wet, underground underset, vegetation growth and pH values etc. influenced the distribution of soil organic matter and nitrogen in wetland.

  17. Polyphenols, fungal enzymes, and the fate of organic nitrogen in a Californian pygmy forest

    Science.gov (United States)

    Slessarev, E.

    2011-12-01

    Polyphenols are a diverse family of plant secondary compounds which may influence litter decay and soil nutrient turnover. The "short circuit" hypothesis for polyphenol function proposes that polyphenolic compounds provision plants with nitrogen in nutrient-poor soils by facilitating the accumulation of organic nitrogen in soil humus. By binding peptides, polyphenols may sequester nitrogen in a bank of recalcitrant organic matter, granting competitive advantage to plants with the mycorrhizal fungi most capable of recapturing the tightly bound organic nitrogen. Specifically, fungi may retrieve nitrogen from polyphenol-peptide complexes with an extracellular enzyme, polyphenol oxidase (PPO). In order to evaluate the "short circuit" hypothesis, I measured soil PPO activity during four seasons in the Mendocino "ecological staircase," a soil age-gradient consisting of a series of wave-cut terraces along stretches of the northern California coast. Stunted, pygmy-forest plants growing in the nutrient-poor soils of the older marine terraces produce more polyphenols than their con-specifics on nutrient-rich younger terraces, potentially influencing PPO facilitated nitrogen cycling. I found that PPO activity reached its maximum in the younger terrace forest during the spring, achieving levels nearly twice as high as those observed on the younger terrace in other seasons and in the older terrace forest year-round. In both terraces, PPO activity was greatest in the organic humus at the soil surface, decreasing dramatically in the lower mineral horizon. When PPO activity reached its maximum in the younger terrace, I found that soil polyphenol content positively correlated (Rsq=0.63) with enzyme activity, suggesting that polyphenols might induce enzyme production. However, in the tannin-rich soil of the pygmy forest on the older terrace, enzyme activity remained low, and was most strongly correlated with soil moisture. The results do not support the hypothesis that nutrient

  18. Nitrogen and dissolved organic carbon (DOC) losses from an artificially drained grassland on organic soils

    Science.gov (United States)

    Tiemeyer, B.; Kahle, P.

    2014-08-01

    Nitrate-nitrogen (NO3-N) as well as dissolved organic carbon (DOC) and nitrogen (DON) concentrations and losses were studied for three and two years, respectively, in a small catchment dominated by a degraded peatland used as intensive grassland. Concentrations in the shallow groundwater were spatially and temporally very variable, with NO3-N being the most dynamic component (7.3 ± 12.5 mg L-1) and ranging from 0 to 79.4 mg L-1. Average NO3-N concentrations of 10.3 ± 5.4 mg L-1 (0 to 25.5 mg L-1) in the ditch draining the catchment and annual NO3-N losses of 19, 35 and 26 kg ha-1 confirmed drained peatlands as an important source of diffuse N pollution. The highest NO3-N losses occurred during the wettest year. Resulting from concentration of 2.4 ± 0.8 mg L-1 (0.7 to 6.2 mg L-1), DON added a further 4.5 to 6.4 kg ha-1 to the N losses and thus formed a relevant (15%) component of the total N losses. Ditch DOC concentrations of 24.9 ± 5.9 mg L-1 (13.1 to 47.7 mg L-1) resulted in DOC losses of 66 kg ha-1 in the wet year of 2006/2007 and 39 kg ha-1 in the dry year of 2007/2008. Ditch DOC concentration were lower than the groundwater DOC concentration of 50.6 ± 15.2 mg L-1 (14.9 to 88.5 mg L-1). Both DOC and N concentrations were governed by hydrological conditions, but NO3-N reacted much faster and clearer on rising discharge rates than DOC, which tended to be higher under drier conditions. In the third year of the study, the superposition of a very wet summer and land use changes from grassland to arable land in a part of the catchment suggests that, under re-wetting conditions with a high groundwater table in summer, NO3-N would diminish quickly, while DOC would remain on a similar level. Further intensification of the land use, on the other hand, would increase N losses to receiving water bodies.

  19. Dynamic Regulation of Nitrogen and Organic Acid Metabolism of Cherry Tomato Fruit as Affected by Different Nitrogen Forms

    Institute of Scientific and Technical Information of China (English)

    XU Xin-Juan; LI Qing-Yu; SONG Xiao-Hui; Shen Qi-Rong; Dong Cai-Xia

    2012-01-01

    Cherry tomatoes (Lycopersicon esculentum Mill.,cv.hongyangli) were hydroponically cultivated in a greenhouse to determine the effect of different nitrogen (N) forms on organic acid concentration and the activities of related enzymes involved in nitrogen and organic acid metabolism during cherry tomato fruit development.The results showed that fruit nitrate reductase (NR) activity was much higher following treatment with 100% NO-3 and 75% NO-3 +25% NH+4 than with 100% NH+4 except at maturity.Glutamine synthetaee (GS) activity trended downward during fruit development under all three treatments.Plants fed 100% NH4+ had the lowest fruit citrate and malate levels at maturity,with the highest malate concentration at an early stage.The activity of phosphoenolpyruvate carboxylase (PEPC) was found to be in accord with the malate concentration with every N source.Under all three N forms,the citrate synthase (CS) activity peaked one week before the citrate concentration.

  20. Removal of Nitrogen,Phosphorus,and Organic Pollutants From Water Using Seeding Type Immobilized Microorganisms

    Institute of Scientific and Technical Information of China (English)

    LIN WANG; LI-JING HUANG; LUO-JIA YUN; FEI TANG; JING-HUI ZHAO; YAN-QUN LIU; XIN ZENG; QI-FANG LUO

    2008-01-01

    Objective To study the possibility of removing nitrogen.phosphorus,and organic pollutants using seeding type immobilized microorganisms.Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen,phosphorus,and organic pollutants with the seeding type immobilized microorganisms.Correlations between the quantity ofheterotrophic bacteria and the total nitrogen(TN),total phosphorus(TP),and toml organic carbon(TOC)in the two lakes were studied.The dominant bacteria were detected.inoculated to the sludge and acclimated by increasing nitrogen,phosphorus and decreasing carbon source in an intermittent,time-controlled and fixed-quantity way.The bacteria were thenused to prepare the seeding type immobilized microorganisms,selecting diatomim as the adsorbent cairtier.The ability and influence factors of removing nitrogen,phosphorus,and organic pollutant from water samples by the seeding type immobilized microorganismswere studied.Results The coefficients of the heterotrophic bacterial quantity correlatedwith TOC,TP,and TN were 0.9143,0.8229,0.7954 in Lake P and 0.9168,0.7187,0.6022 in Lake M.Ton swains of dominant heterotrophic bacteria belonging to Pseudomonas,Coccus,Aeromonas,Bacillus,and Enterobateriaceae,separately,were isolated.The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24h,pH=7.0-8.0.and quantity of the immobilized microorganisms=0.75-1g/50 mL.The removal rates of TOC,TP,and TN under the above conditions were 80.2%,81.6%,and 86.8%,respectively.Conclusion The amount of heterotrophic bacteria in the two lakes was correlatexl with TOC,TP, and TN.These bacteria could be acclimatized and prepared for the immobilizedmicroorganisms which could effectively remove nitrogen,phosphorus,and mixed organic pollutants in the water sample.

  1. Kinetic modelling of nitrogen and organics removal in vertical and horizontal flow wetlands.

    Science.gov (United States)

    Saeed, Tanveer; Sun, Guangzhi

    2011-05-01

    This paper provides a comparative evaluation of the kinetic models that were developed to describe the biodegradation of nitrogen and organics removal in wetland systems. Reaction kinetics that were considered in the model development included first order kinetics, Monod and multiple Monod kinetics; these kinetics were combined with continuous-stirred tank reactor (CSTR) or plug flow pattern to produce equations to link inlet and outlet concentrations of each key pollutants across a single wetland. Using three statistical parameters, a critical evaluation of five potential models was made for vertical and horizontal flow wetlands. The results recommended the models that were developed based on Monod models, for predicting the removal of nitrogen and organics in a vertical and horizontal flow wetland system. No clear correlation was observed between influent BOD/COD values and kinetic coefficients of BOD(5) in VF and HF wetlands, illustrating that the removal of biodegradable organics was insensitive to the nature of organic matter. Higher effluent COD/TN values coincided with greater denitrification kinetic coefficients, signifying the dependency of denitrification on the availability of COD in VF wetland systems. In contrast, the trend was opposite in HF wetlands, indicating that availability of NO(3)-N was the main limiting step for nitrogen removal. Overall, the results suggested the possible application of the developed alternative predictive models, for understanding the complex biodegradation routes of nitrogen and organics removal in VF and HF wetland systems.

  2. Ultraviolet irradiation effects incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter

    Science.gov (United States)

    Thorn, Kevin A.; Cox, Larry G.

    2012-01-01

    One of the concerns regarding the safety and efficacy of ultraviolet radiation for treatment of drinking water and wastewater is the fate of nitrate, particularly its photolysis to nitrite. In this study, 15N NMR was used to establish for the first time that UV irradiation effects the incorporation of nitrate and nitrite nitrogen into aquatic natural organic matter (NOM). Irradiation of 15N-labeled nitrate in aqueous solution with an unfiltered medium pressure mercury lamp resulted in the incorporation of nitrogen into Suwannee River NOM (SRNOM) via nitrosation and other reactions over a range of pH from approximately 3.2 to 8.0, both in the presence and absence of bicarbonate, confirming photonitrosation of the NOM. The major forms of the incorporated label include nitrosophenol, oxime/nitro, pyridine, nitrile, and amide nitrogens. Natural organic matter also catalyzed the reduction of nitrate to ammonia on irradiation. The nitrosophenol and oxime/nitro nitrogens were found to be susceptible to photodegradation on further irradiation when nitrate was removed from the system. At pH 7.5, unfiltered irradiation resulted in the incorporation of 15N-labeled nitrite into SRNOM in the form of amide, nitrile, and pyridine nitrogen. In the presence of bicarbonate at pH 7.4, Pyrex filtered (cutoff below 290–300 nm) irradiation also effected incorporation of nitrite into SRNOM as amide nitrogen. We speculate that nitrosation of NOM from the UV irradiation of nitrate also leads to production of nitrogen gas and nitrous oxide, a process that may be termed photo-chemodenitrification. Irradiation of SRNOM alone resulted in transformation or loss of naturally abundant heterocyclic nitrogens.

  3. [Effects of simulated nitrogen deposition on organic matter leaching in forest soil].

    Science.gov (United States)

    Duan, Lei; ma, Xiao-Xiao; Yu, De-Xiang; Tan, Bing-Quan

    2013-06-01

    The impact of nitrogen deposition on the dynamics of carbon pool in forest soil was studied through a field experiment at Tieshanping, Chongqing in Southwest China. The changes of dissolved organic matter (DOM) concentration in soil water in different soil layers were monitored for five years after addition of ammonium nitrate (NH4NO3) or sodium nitrate (NaNO3) at the same dose as the current nitrogen deposition to the forest floor. The results indicated that the concentration and flux of dissolved organic carbon (DOC) were increased in the first two years and then decreased by fertilizing. Fertilizing also reduced the DOC/DON (dissolved organic nitrogen) ratio of soil water in the litter layer and the DOC concentration of soil water in the upper mineral layer, but had no significant effect on DOC flux in the lower soil layer. Although there was generally no effect of increasing nitrogen deposition on the forest carbon pool during the experimental period, the shift from C-rich to N-rich DOM might occur. In addition, the species of nitrogen deposition, i. e., NH4(+) and NO3(-), did not show difference in their effect on soil DOM with the same equivalence.

  4. Is an organic nitrogen source needed for cellulase production by Trichoderma reesei Rut-C30?

    Science.gov (United States)

    Rodriguez-Gomez, Divanery; Hobley, Timothy John

    2013-11-01

    The effect of organic and inorganic nitrogen sources on Trichoderma reesei Rut-C30 cellulase production was investigated in submerged cultivations. Stirred tank bioreactors and shake flasks, with and without pH control, respectively, were employed. The experimental design involved the addition of individual organic nitrogen sources (soy peptone, glutamate, glycine and alanine) within a basal medium containing Avicel (i.e. micro crystalline cellulose) and ammonium sulphate. It was found that in the shake flask experiments, the highest cellulase activities (~0.1 ± 0.02 FPU ml(-1)) were obtained with media containing soy peptone (3-6 g l(-1)) and glutamate (3.6 g l(-1)). However, these improvements in the cellulase titers in the presence of the organic nitrogen sources appeared to be related to smaller changes in the pH of the medium. This was confirmed using stirred tank bioreactors with pH control. No significant differences were observed in the highest cellulase titers and the protein pattern (according to the SDS-PAGE) of supernatants from pH controlled stirred tank bioreactor cultivations, when different nitrogen sources were used in the medium. Here the cellulase activities (~1.0 ± 0.2 FPU ml(-1)) were also much greater (8-150 times) than in shake flask cultivation. Consequently, the addition of ammonium sulphate as sole nitrogen source to Avicel basal medium is recommended when performing cultivations in stirred tank bioreactors with strict pH controlled conditions.

  5. Biophysical controls over concentration and depth distribution of soil organic carbon and nitrogen in desert playas

    Science.gov (United States)

    McKenna, Owen P.; Sala, Osvaldo E.

    2016-12-01

    Playa wetlands are important areas of soil organic carbon and nutrient storage in drylands. We conducted this study to assess how catchment biophysical variables control soil organic carbon and nitrogen in playas and how playas function differently than upland ecosystems. We found that playa organic carbon and nitrogen corresponded primarily with catchment vegetation cover and secondarily with catchment area, slope, and soil texture. The effect of increased organic matter production associated with high catchment vegetation cover overshadowed the potential effect of reduced run-on. We also found soil carbon and nitrogen profiles to be significantly shallower in playas than uplands. This trend is correlated with evidence of sedimentation and shallow-rooted plants in playas. Upland soils had a deeper carbon and nitrogen profile, which correlated with organic matter being generated by deeply rooted vegetation. In playas, C:N ratios remained constant through depth but in uplands, C:N ratios increased through depth. We found evidence that differences in rooting depth distributions and soil texture may explain these C:N variations between uplands and playas. In uplands, clay concentration increased with depth, whereas in playas, clay concentration did not change with depth, which highlighted the important role of sedimentation in these ecosystems. Our results suggest that small changes in playa catchment vegetation cover in response to climate change or grazing intensity would greatly impact playa soil organic carbon and nitrogen stocks. This effect would be due to the playa soils dependence on allochthonous organic matter and the large upland area that drains into playas.

  6. Contribution of water soluble organic nitrogen to total nitrogen in marine aerosols over the East China Sea and western North Pacific

    Digital Repository Service at National Institute of Oceanography (India)

    Nakamura, T.; Ogawa, H.; DileepKumar, M.; Uematsu, M.

    This paper presents information on concentrations, size distributions, geographical distributions and sources of water-soluble organic nitrogen (ONws) in aerosols over the East China Sea and western North Pacific to understand its impact...

  7. Dissolved organic nitrogen (DON) losses from nested artificially drained lowland catchments with contrasting soil types

    Science.gov (United States)

    Tiemeyer, Bärbel; Kahle, Petra; Lennartz, Bernd

    2010-05-01

    Artificial drainage is a common practice to improve moisture and aeration conditions of agricultural land. It shortens the residence time of water in the soil and may therefore contribute to the degradation of peatlands as well as to the still elevated level of diffuse pollution of surface water bodies, particularly if flow anomalies like preferential flow cause a further acceleration of water and solute fluxes. Especially in the case of nitrate, artificially drained sub-catchments are found to control the catchment-scale nitrate losses. However, it is frequently found that nitrate losses and nitrogen field balances do not match. At the same time, organic fertilizers are commonly applied and, especially in lowland catchments, organic soils have been drained for agricultural use. Thus, the question arises whether dissolved organic nitrogen (DON) forms an important component of the nitrogen losses from artificially drained catchments. However, in contrast to nitrate and even to dissolved organic carbon (DOC), this component is frequently overlooked, especially in nested catchment studies with different soil types and variable land use. Here, we will present data from a hierarchical water quantity and quality measurement programme in the federal state Mecklenburg-Vorpommern (North-Eastern Germany). The monitoring programme in the pleistocene lowland catchment comprises automatic sampling stations at a collector drain outlet (4.2 ha catchment), at a ditch draining arable land on mineral soils (179 ha), at a ditch mainly draining grassland on organic soils (85 ha) and at a brook with a small rural catchment (15.5 km²) of mixed land use and soil types. At all sampling stations, daily to weekly composite samples were taken, while the discharge and the meteorological data were recorded continuously. Water samples were analyzed for nitrate-nitrogen, ammonium-nitrogen and total nitrogen. We will compare two years: 2006/07 was a very wet year (P = 934 mm) with a high summer

  8. Lower nitrogen supply gave better fruit quality in organic apples

    OpenAIRE

    Lindhard Pedersen, Hanne; Bertelsen , Marianne

    2003-01-01

    The use of scab resistant apple varieties is the best way to prevent infections of apple scab (Venturia inaequalis). In 1995 the then 10 most promising resistant apple varieties for Denmark where planted at Research Centre Årslev, Denmark in an organic production system. Tree different cover crops where established in the allyways. Weed cleaning in the tree row was done mechanically and the trees were kept unfertilised. The annual shoot growth, nutrients in leaf sample, mineralised nitroge...

  9. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    Science.gov (United States)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin; Siemens, Jan

    2016-08-01

    Freezing can affect concentrations and spectroscopic properties of dissolved organic matter (DOM) in water samples. Nevertheless, water samples are regularly frozen for sample preservation. In this study we tested the effect of different freezing methods (standard freezing at -18 °C and fast-freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC concentrations, UV-vis absorption and fluorescence excitation-emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at -18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties of DOM.

  10. Is an organic nitrogen source needed for cellulase production by Trichoderma reesei Rut-C30?

    DEFF Research Database (Denmark)

    Rodríguez Gómez, Divanery; Hobley, Timothy John

    2013-01-01

    of individual organic nitrogen sources (soy peptone, glutamate, glycine and alanine) within a basal medium containing Avicel (i.e. micro crystalline cellulose) and ammonium sulphate. It was found that in the shake flask experiments, the highest cellulase activities (~0.1 ± 0.02 FPU ml−1) were obtained...

  11. Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a

    NARCIS (Netherlands)

    Heijboer, Amber; Berge, ten Hein F.M.; Ruiter, de Peter C.; Jørgensen, Helene Bracht; Kowalchuk, George A.; Bloem, Jaap

    2016-01-01

    Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultan

  12. The effect of organic nitrogen sources on recombinant glucoamylase production by Aspergillus niger in chemostat culture

    NARCIS (Netherlands)

    Swift, R.J.; Karandikar, A.; Griffen, A.M.; Punt, P.J.; Hondel, C.A.M.J.J. van den; Robson, G.D.; Trinci, A.P.J.; Wiebe, M.G.

    2000-01-01

    Aspergillus niger B1, a recombinant strain carrying 20 extra copies of the native glucoamylase gene, was grown in glucose-limited chemostat cultures supplemented with various organic nitrogen sources (dilution rate 0.12 ± 0.01 h-1, pH 5.4). In cultures supplemented with L-alanine, L-methionine, casa

  13. The spatial representations acquired in CA3 by self-organizing recurrent connections

    Directory of Open Access Journals (Sweden)

    Erika eCerasti

    2013-07-01

    Full Text Available Neural computation models have hypothesized that the dentate gyrus drives the storage in the CA3 network of new memories including, e.g. in rodents, spatial memories. Can recurrent CA3 connections self-organize, during storage, and form what have been called continuous attractors, or charts – so that they express spatial information later, when aside from a partial cue the information may not be available in the inputs? We use a simplified mathematical network model to contrast the properties of spatial representations self-organized through simulated Hebbian plasticity with those of charts pre-wired in the synaptic matrix, a control case closer to the ideal notion of continuous attractors. Both models form granular quasi-attractors, characterized by drift, which approach continuous ones only in the limit of an infinitely large network. The two models are comparable in terms of precision, but not of accuracy: with self-organized connections, the metric of space remains distorted, ill-adequate for accurate path integration, even when scaled up to the real hippocampus. While prolonged self-organization makes charts somewhat more informative about position in the environment, some positional information is surprisingly present also about environments never learned, borrowed, as it were, from unrelated charts. In contrast, context discrimination decreases with more learning, as different charts tend to collapse onto each other. These observations challenge the feasibility of the idealized CA3 continuous chart concept, and are consistent with a CA3 specialization for episodic memory rather than path integration.

  14. Nitrogen-rich higher-molecular soil organic compounds patterned by lignin degradation products: Considerations on the nature of soil organic nitrogen

    Science.gov (United States)

    Liebner, Falk; Bertoli, Luca; Pour, Georg; Klinger, Karl; Ragab, Tamer; Rosenau, Thomas

    2016-04-01

    The pathways leading to accumulation of covalently bonded nitrogen in higher-molecular soil organic matter (SOM) are still a controversial issue in soil science and geochemistry. Similarly, structural elucidation of the variety of the types of nitrogenous moieties present in SOM is still in its infancy even though recent NMR studies suggest amide-type nitrogen to form the majority of organically bonded nitrogen which is, however, frequently not in accordance with the results of wet-chemical analyses. Following the modified polyphenol theory of Flaig and Kononova but fully aware of the imperfection of a semi-abiotic simulation approach, this work communicates the results of a study that investigated some potential nitrogen accumulation pathways occurring in the re-condensation branch of the theory following the reactions between well-known low-molecular lignin and carbohydrate degradation products with nitrogenous nucleophiles occurring in soils under aerobic conditions. Different low-molecular degradation products of lignin, cellulose, and hemicellulose, such as hydroquinone, methoxyhydroquinone, p-benzoquinone, 2,5-dihydroxy-[1,4]benzoquinone, glucose, xylose, and the respective polysaccharides, i.e. cellulose, xylan as well as various types of lignin were subjected to a joint treatment with oxygen and low-molecular N-nucleophiles, such as ammonia, amines, and amino acids in aqueous conditions, partly using respective 15N labeled compounds for further 15N CPMAS NMR studies. Product mixtures derived from mono- and polysaccharides have been comprehensively fractionated and analyzed by GC/MS after derivatization. Some of ammoxidized polyphenols and quinones have been analyzed by X-ray photoelectron spectroscopy. Some products, such as those obtained from ammoxidation of methoxy hydroquinone using 15N labeled ammonia were fractionated following the IHSS protocol. Individual humin (H), humic acid (HA), and fulvic acid (FA) fractions were subjected to elemental analyses

  15. Soil Organic Nitrogen and Its Contribution to Crop Production

    Institute of Scientific and Technical Information of China (English)

    LI Sheng-xiu; WANG Zhao-hui; MIAO Yan-fang; LI Shi-qing

    2014-01-01

    Plant growth and crop production depend to a large extent on soil N supplying capacity (SNSC):The higher the SNSC, the higher the dependence of crops on soil and the lower the N fertilizer recovery. Of the SNSC, soil organic N (ON) played a key role in supplying N nutrient to crop production and still does in many subsistence and low-input farming systems. In this paper, soil ON contents, types, chemical components and its contribution to plant production are reviewed up to date in details, the characteristics of ON in dryland soils discussed together with its chemical components, and the mineralization and availability to plants of some important chemical components are emphasized at the last part for practical considerations.

  16. Dissolved organic carbon and dissolved organic nitrogen data collected using bottle in a world wide distribution from 02 September 1998 to 02 November 2003 (NODC Accession 0002403)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) data were collected using bottle casts in a world wide distribution. Data were collected from 02...

  17. Effect of spray aeration on organics and nitrogen removal in vertical subsurface flow constructed wetland.

    Science.gov (United States)

    Ding, Yi; Wang, Wei; Song, Xin-Shan; Wang, Gang; Wang, Yu-Hui

    2014-12-01

    The objective of present study was to assess the simultaneous removal of organics and nitrogen by four lab-scale vertical subsurface flow constructed wetlands (V-SFCWs). The emergent plants employed were Canna indica. Five-month experiments showed that the planted and aerated system largely reduced the COD by 95%, NH4 by 88% and total inorganic nitrogen (TIN) by 83%. It outperformed the unplanted or simple aerated system and was much better than non-aerated system. The study provided a strong evidence to support widespread research and application of spray aeration as a low-cost and energy-efficient aeration technology in V-SFCWs.

  18. Patterns of dissolved organic carbon and nitrogen fluxes in deciduous and coniferous forests under historic high nitrogen deposition

    Science.gov (United States)

    Sleutel, S.; Vandenbruwane, J.; de Schrijver, A.; Wuyts, K.; Moeskops, B.; Verheyen, K.; de Neve, S.

    2009-12-01

    Numerous recent studies have indicated that dissolved organic carbon (DOC) and nitrogen (DON) play an important role in C and N cycling in natural ecosystems, and have shown that N deposition alters the concentrations and fluxes of dissolved organic substances and may increase leaching losses from forests. Our study was set up to accurately quantify concentrations and flux patterns of DOC, DON and dissolved inorganic nitrogen (DIN) in deciduous and coniferous forest in Flanders, Belgium, under historical high nitrogen deposition. We measured DOC, DON and DIN concentrations at two weekly intervals in a silver birch (SB) stand, a corsican pine (CP) stand and a pine stand with higher N deposition (CPN), and used the SWAP model (calibrated with PEST) for generating accurate water and matter fluxes. The input with precipitation was an important source of DON, but not for DOC. Release of DOC from the forest floor was minimally affected by forest type, but higher N deposition (CPN stand) caused an 82% increase of DOC release from the forest floor. Adsorption to mineral soil material rich in iron and/or aluminum oxyhydroxides was suggested to be the most important process removing DOC from the soil solution, responsible for substantial retention (67-84%) of DOC entering the mineral soil profile with forest floor leachate. Generally, DON was less reactive (i.e. less removal from the soil solution) than DOC, resulting in decreasing DOC/DON ratios with soil depth. We found increased DOC retention in the mineral soil as a result of higher N deposition (84 kg ha-1 yr-1 additional DOC retention in CPN compared to CP). Overall DON leaching losses were 2.2, 3.3 and 5.0 kg N yr-1 for SB, CP and CPN, respectively, contributing between 9-28% to total dissolved N (TDN) leaching. The relative contribution to TDN leaching from DON loss from SB and CP was mainly determined by (large) differences in DIN leaching. The large TDN leaching losses are alarming, especially in the CPN stand that

  19. Patterns of dissolved organic carbon (DOC) and nitrogen (DON) fluxes in deciduous and coniferous forests under historic high nitrogen deposition

    Science.gov (United States)

    Sleutel, S.; Vandenbruwane, J.; de Schrijver, A.; Wuyts, K.; Moeskops, B.; Verheyen, K.; de Neve, S.

    2009-07-01

    Numerous recent studies have indicated that dissolved organic carbon (DOC) and nitrogen (DON) play an important role in C and N cycling in natural ecosystems, and have shown that N deposition alters the concentrations and fluxes of dissolved organic substances and may increase leaching losses from forests. Our study was set up to accurately quantify concentrations and flux patterns of DOC, DON and dissolved inorganic nitrogen (DIN) in deciduous and coniferous forest in Flanders under historical high nitrogen deposition. We measured DOC, DON and DIN concentrations at two weekly intervals in a silver birch (SB) stand, a corsican pine (CP) stand and a pine stand with higher N deposition (CPN), and used the SWAP model (calibrated with PEST) for generating accurate water and matter fluxes. The input with precipitation was an important source of DON, but not for DOC. Release of DOC from the forest floor was minimally affected by forest type, but higher N deposition (CPN stand) caused an 82% increase of DOC release from the forest floor. Adsorption to mineral soil material rich in iron and/or aluminum oxyhydroxides was suggested to be the most important process removing DOC from the soil solution, responsible for substantial retention (67-84%) of DOC entering the mineral soil profile with forest floor leachate. Generally, DON was less reactive (i.e. less removal from the soil solution) than DOC, resulting in decreasing DOC/DON ratios with soil depth. We found increased DOC retention in the mineral soil as a result of higher N deposition (84 kg N ha-1 yr-1 additional DOC retention in CPN compared to CP). Overall DON leaching losses were 2.2, 3.3 and 5.0 kg N ha-1 yr-1 for SB, CP and CPN, respectively, contributing between 9-28% to total dissolved N (TDN) leaching. DON loss from SB and CP was not much higher than from unpolluted forests, and its relative contribution to TDN leaching was mainly determined by (large) differences in DIN leaching. The large TDN leaching losses

  20. Patterns of dissolved organic carbon (DOC and nitrogen (DON fluxes in deciduous and coniferous forests under historic high nitrogen deposition

    Directory of Open Access Journals (Sweden)

    S. Sleutel

    2009-07-01

    Full Text Available Numerous recent studies have indicated that dissolved organic carbon (DOC and nitrogen (DON play an important role in C and N cycling in natural ecosystems, and have shown that N deposition alters the concentrations and fluxes of dissolved organic substances and may increase leaching losses from forests. Our study was set up to accurately quantify concentrations and flux patterns of DOC, DON and dissolved inorganic nitrogen (DIN in deciduous and coniferous forest in Flanders under historical high nitrogen deposition. We measured DOC, DON and DIN concentrations at two weekly intervals in a silver birch (SB stand, a corsican pine (CP stand and a pine stand with higher N deposition (CPN, and used the SWAP model (calibrated with PEST for generating accurate water and matter fluxes. The input with precipitation was an important source of DON, but not for DOC. Release of DOC from the forest floor was minimally affected by forest type, but higher N deposition (CPN stand caused an 82% increase of DOC release from the forest floor. Adsorption to mineral soil material rich in iron and/or aluminum oxyhydroxides was suggested to be the most important process removing DOC from the soil solution, responsible for substantial retention (67–84% of DOC entering the mineral soil profile with forest floor leachate. Generally, DON was less reactive (i.e. less removal from the soil solution than DOC, resulting in decreasing DOC/DON ratios with soil depth. We found increased DOC retention in the mineral soil as a result of higher N deposition (84 kg N ha−1 yr−1 additional DOC retention in CPN compared to CP. Overall DON leaching losses were 2.2, 3.3 and 5.0 kg N ha−1 yr−1 for SB, CP and CPN, respectively, contributing between 9–28% to total dissolved N (TDN leaching. DON loss from SB and CP was not much higher than from unpolluted forests, and its relative contribution to TDN leaching was mainly determined by

  1. Patterns of dissolved organic carbon and nitrogen fluxes in deciduous and coniferous forests under historic high nitrogen deposition

    Directory of Open Access Journals (Sweden)

    S. Sleutel

    2009-12-01

    Full Text Available Numerous recent studies have indicated that dissolved organic carbon (DOC and nitrogen (DON play an important role in C and N cycling in natural ecosystems, and have shown that N deposition alters the concentrations and fluxes of dissolved organic substances and may increase leaching losses from forests. Our study was set up to accurately quantify concentrations and flux patterns of DOC, DON and dissolved inorganic nitrogen (DIN in deciduous and coniferous forest in Flanders, Belgium, under historical high nitrogen deposition. We measured DOC, DON and DIN concentrations at two weekly intervals in a silver birch (SB stand, a corsican pine (CP stand and a pine stand with higher N deposition (CPN, and used the SWAP model (calibrated with PEST for generating accurate water and matter fluxes. The input with precipitation was an important source of DON, but not for DOC. Release of DOC from the forest floor was minimally affected by forest type, but higher N deposition (CPN stand caused an 82% increase of DOC release from the forest floor. Adsorption to mineral soil material rich in iron and/or aluminum oxyhydroxides was suggested to be the most important process removing DOC from the soil solution, responsible for substantial retention (67–84% of DOC entering the mineral soil profile with forest floor leachate. Generally, DON was less reactive (i.e. less removal from the soil solution than DOC, resulting in decreasing DOC/DON ratios with soil depth. We found increased DOC retention in the mineral soil as a result of higher N deposition (84 kg ha−1 yr−1 additional DOC retention in CPN compared to CP. Overall DON leaching losses were 2.2, 3.3 and 5.0 kg N yr−1 for SB, CP and CPN, respectively, contributing between 9–28% to total dissolved N (TDN leaching. The relative contribution to TDN leaching from DON loss from SB and CP was mainly determined by (large differences in DIN leaching. The large TDN leaching

  2. Composition of dissolved organic nitrogen in rivers associated with wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Akira, E-mail: akiraw@agr.nagoya-u.ac.jp [Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601 (Japan); Tsutsuki, Kiyoshi [Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan); Inoue, Yudzuru [Graduate School of Science and Engineering, Saitama University, Sakura, Saitama 338-8570 (Japan); Maie, Nagamitsu [School of Veterinary Medicine, Kitasato University, Towada, Aomori 034-8628 (Japan); Melling, Lulie [Tropical Peat Research Laboratory Unit, Chief Minister' s Department, Jalan Badruddin 93400, Kuching, Sarawak (Malaysia); Jaffé, Rudolf [Southeast Environmental Research Center, Florida International University, 3000 NE 151 Str., Marine Sciences Building, North Miami, FL 33181 (United States); Department of Chemistry and Biochemistry, Florida International University, 3000 NE 151 Str., Marine Sciences Building, North Miami, FL 33181 (United States)

    2014-09-15

    As basic information for assessing reactivity and functionality of wetland-associated dissolved organic matter (DOM) based on their composition and structural properties, chemical characteristics of N in ultrafiltered DOM (UDON; > 1 kD) isolated from wetland-associated rivers in three climates (cool-temperate, Hokkaido, Japan; sub-tropical, Florida, USA; tropical, Sarawak, Malaysia) were investigated. The UDON was isolated during dry and wet seasons, or during spring, summer, and autumn. The proportion of UDON present as humic substances, which was estimated as the DAX-8 adsorbed fraction, ranged from 47 to 91%, with larger values in the Sarawak than at the other sites. The yield of hydrolyzable amino acid N ranged 1.24 to 7.01mg g{sup −1}, which correlated positively to the total N content of UDOM and tended to be larger in the order of Florida > Hokkaido > Sarawak samples. X-ray photoelectron N1s spectra of UDON showed a strong negative correlation between the relative abundances of amide/peptide N and primary amine N. The relative abundances of amide/peptide N and primary amine N in the Sarawak samples were smaller (70–76%) and larger (20–23%) respectively compared to those (80–88% and 4–9%) in the Florida and Hokkaido samples. Assuming terminal amino groups and amide N of peptides as major constituents of primary amine N and amide/peptide N, respectively, the average molecular weight of peptides was smaller in the Sarawak samples than that in the Florida and Hokkaido samples. Seasonal variations in UDON composition were scarce in the Sarawak and Florida samples, whereas the distribution of humic substance-N and nonhumic substance-N and compositions of amino acids and N functional groups showed a clear seasonality in the Hokkaido samples. While aromatic N increased from spring to autumn, contributions from fresh proteinaceous materials were also enhanced during autumn, resulting in the highest N content of UDOM for this season. - Highlights: • DON in

  3. Organic nitrogen mineralization rate in sewage sludge-amended mine soil

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Tercero, A.M.; Andrade, M.L.; Marcet, P. [University of Vigo, Vigo (Spain)

    2005-07-01

    This study was carried out on lignite mine tailings at Meirama (northwestern Spain). A laboratory experiment was conducted to investigate the effects of amending lignite mine spoil with municipal sewage sludge at rates of 5, 25, and 50 Mg ha{sup -1} triplicate samples of soil, and each treatment was incubated from 0 to 90 days at constant moisture and temperature (85% air relative humidity and 25{degree}C). Each sewage sludge dose was packed into PVC columns and inserted vertically into the recipient containing the upper layer of mine soil. A set of the incubated columns was removed at 15, 45, and 90 days, and the soil underlying each column was sampled for analysis. Nitrogen (N) mineralization rate and the evolution of soil pH, C/N ratio, organic matter, total N, organic-N, NO{sub 3}{sup -}-N, and NH{sub 4}{sup +}-N content were measured. Sewage sludge application produced an immediate increase of the inorganic N at all dosage levels, mainly in the ammonium form. The nitrogen mineralization in the amended soils was higher than in the control soil, mainly in the case of those treated with 25 Mg ha{sup -1}. The net mineralized organic N was always positive, except at the end of the period of incubation in the 5 Mg ha{sup -1} sewage sludge treated soil. The nitrogen mineralization rate, calculated as a decrease in the organic nitrogen content, overestimates the amount of inorganic nitrogen that is available. The measurement of the cumulative amount of NH{sub 4}{sup +}-N and NO{sub 3}{sup -}-N provided a much lower estimation of N mineralization under incubation conditions.

  4. Nitrogen dynamics in organic and conventional cotton production systems in India

    Science.gov (United States)

    Duboc, O.; Adamtey, N.; Forster, D.; Cadisch, G.

    2012-04-01

    Ongoing population growth still represents a challenge to agricultural production (food, fiber and fuel material supply). In spite of the undeniable achievements reached with the "green revolution" technologies, there is a growing awareness among scientists and policy makers that diverse and integrated approaches which are both productive and sustainable are now necessary to meet the agricultural challenges. Integrated and organic agriculture are such alternatives which need to be better investigated and implemented. While long-term experiments in temperate regions have assessed the effect of organic agriculture on different crops and soil quality, there is currently a lack of reliable data from tropical regions, such as findings arising from long-term systems comparison trials. This has necessitated a long-term system comparison trials in Kenya, Bolivia and India by the Research Institute of Organic Agriculture (FiBL) and its partners (icipe, BioRe, Ecotop and Institute of Ecology) (www.systems-comparison.fibl.org). In India the project is based in Madhya Pradesh, in which organic and conventional production systems are being compared in a 2-yr crop rotation - cotton (yr 1) and soybean-wheat (yr 2). The field trial is planned for a time span of 10-20 years, in order to investigate long-term effects of those production systems on yields, soil characteristics, or economic return. A PhD study is incorporated into this project to investigate the effect of the production systems on soil characteristics. The main focus will be on nitrogen cycling under the different production systems. Particular attention will be given to nitrogen use efficiencies and the synchrony of nitrogen availability (e.g. nitrogen mineralization with the polyethylene bag technique, monitoring of soil mineral N) with plant nitrogen uptake, for which allometric equations will be calibrated in order to circumvent destructive sampling on the plots of the long-term experiment. Nitrogen losses

  5. Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

    Science.gov (United States)

    Yu, Qiaogang; Ma, Junwei; Zou, Ping; Lin, Hui; Sun, Wanchun; Yin, Jianzhen; Fu, Jianrong

    2015-01-01

    The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

  6. Determination of organic milk authenticity using carbon and nitrogen natural isotopes.

    Science.gov (United States)

    Chung, Ill-Min; Park, Inmyoung; Yoon, Jae-Yeon; Yang, Ye-Seul; Kim, Seung-Hyun

    2014-10-01

    Natural stable isotopes of carbon and nitrogen ((12)C, (13)C, (14)N, (15)N) have abundances unique to each living creature. Therefore, measurement of the stable isotope ratio of carbon and nitrogen (δ(13)C=(13)C/(12)C, δ(15)N=(15)N/(14)N) in milk provides a reliable method to determine organic milk (OM) authenticity. In the present study, the mean δ(13)C value of OM was higher than that of conventional milk (CM), whereas the mean δ(15)N value of OM was lower than that of CM; nonetheless both δ(13)C and δ(15)N values were statistically different for the OM and CM (Pauthenticity using stable isotopes of carbon and nitrogen.

  7. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    DEFF Research Database (Denmark)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin;

    2016-01-01

    concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax......-freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC...... component 4 (EXmax: 280 nm, EXmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties...

  8. Nitrogen reduction pathways in estuarine sediments: Influences of organic carbon and sulfide

    Science.gov (United States)

    Plummer, Patrick; Tobias, Craig; Cady, David

    2015-10-01

    Potential rates of sediment denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were mapped across the entire Niantic River Estuary, CT, USA, at 100-200 m scale resolution consisting of 60 stations. On the estuary scale, denitrification accounted for ~ 90% of the nitrogen reduction, followed by DNRA and anammox. However, the relative importance of these reactions to each other was not evenly distributed through the estuary. A Nitrogen Retention Index (NIRI) was calculated from the rate data (DNRA/(denitrification + anammox)) as a metric to assess the relative amounts of reactive nitrogen being recycled versus retained in the sediments following reduction. The distribution of rates and accompanying sediment geochemical analytes suggested variable controls on specific reactions, and on the NIRI, depending on position in the estuary and that these controls were linked to organic carbon abundance, organic carbon source, and pore water sulfide concentration. The relationship between NIRI and organic carbon abundance was dependent on organic carbon source. Sulfide proved the single best predictor of NIRI, accounting for 44% of its observed variance throughout the whole estuary. We suggest that as a single metric, sulfide may have utility as a proxy for gauging the distribution of denitrification, anammox, and DNRA.

  9. Amount, composition and seasonality of dissolved organic carbon and nitrogen export from agriculture in contrasting climates

    DEFF Research Database (Denmark)

    Graeber, Daniel; Meerhof, Mariana; Zwirnmann, Elke

    2014-01-01

    Agricultural catchments are potentially important but often neglected sources of dissolved organic matter (DOM), of which a large part is dissolved organic carbon (DOC) and nitrogen (DON). DOC is an important source of aquatic microbial respiration and DON may be an important source of nitrogen...... to aquatic ecosystems. However, there is still a lack of comprehensive studies on the amount, composition and seasonality of DOM export from agricultural catchments in different climates. The aim of our study was to assess the amount, composition and seasonality of DOM in a total of four streams in the wet......-temperate and subtropical climate of Denmark and Uruguay, respectively. In each climate, we investigated one stream with extensive agriculture (mostly pasture) and one stream with intensive agriculture (mostly intensively used arable land) in the catchment. We sampled each stream taking grab samples fortnightly for two...

  10. Amount, composition and seasonality of dissolved organic carbon and nitrogen export from agriculture in contrasting climates

    DEFF Research Database (Denmark)

    Graeber, Daniel; Goyenola, Guillermo; Meerhoff, Marianna

    Agricultural catchments are potentially important but often neglected sources of dissolved organic matter (DOM), of which a large part is dissolved organic carbon (DOC) and nitrogen (DON). DOC is an important source of aquatic microbial respiration and DON may be an important source of nitrogen...... to aquatic ecosystems. However, there is still a lack of comprehensive studies on the amount, composition and seasonality of DOM export from agricultural catchments in different climates. The aim of our study was to assess the amount, composition and seasonality of DOM in a total of four streams in the wet......-temperate and subtropical climate of Denmark and Uruguay, respectively. In each climate, we investigated one stream with extensive agriculture (mostly pasture) and one stream with intensive agriculture (mostly intensively used arable land) in the catchment. We sampled each stream taking grab samples fortnightly for two...

  11. A new fungal endophyte, Scolecobasidium humicola, promotes tomato growth under organic nitrogen conditions.

    Directory of Open Access Journals (Sweden)

    Rola S Mahmoud

    Full Text Available A new fungal endophyte, Scolecobasidium humicola, was identified as a common dark septate endophytic fungal (DSE species under both natural and agricultural conditions. This fungus was found to grow endophylically in the roots of tomato seedlings. Light microscopy of cross-sections of colonized tomato roots showed that the intercellular, pigmented hyphae of the fungus were mostly limited to the epidermal layer and formed outer mantle-like structures. Two isolates of S. humicola, H2-2 and F1-3, have shown the ability to increase plant biomass with an organic nitrogen source. This finding is the first report of S. humicola as an endophyte and could help to improve plant growth with organic nitrogen sources.

  12. A new fungal endophyte, Scolecobasidium humicola, promotes tomato growth under organic nitrogen conditions.

    Science.gov (United States)

    Mahmoud, Rola S; Narisawa, Kazuhiko

    2013-01-01

    A new fungal endophyte, Scolecobasidium humicola, was identified as a common dark septate endophytic fungal (DSE) species under both natural and agricultural conditions. This fungus was found to grow endophylically in the roots of tomato seedlings. Light microscopy of cross-sections of colonized tomato roots showed that the intercellular, pigmented hyphae of the fungus were mostly limited to the epidermal layer and formed outer mantle-like structures. Two isolates of S. humicola, H2-2 and F1-3, have shown the ability to increase plant biomass with an organic nitrogen source. This finding is the first report of S. humicola as an endophyte and could help to improve plant growth with organic nitrogen sources.

  13. Organic nitrogen rearranges both structure and activity of the soil-borne microbial seedbank

    Science.gov (United States)

    Leite, Márcio F. A.; Pan, Yao; Bloem, Jaap; Berge, Hein ten; Kuramae, Eiko E.

    2017-01-01

    Use of organic amendments is a valuable strategy for crop production. However, it remains unclear how organic amendments shape both soil microbial community structure and activity, and how these changes impact nutrient mineralization rates. We evaluated the effect of various organic amendments, which range in Carbon/Nitrogen (C/N) ratio and degradability, on the soil microbiome in a mesocosm study at 32, 69 and 132 days. Soil samples were collected to determine community structure (assessed by 16S and 18S rRNA gene sequences), microbial biomass (fungi and bacteria), microbial activity (leucine incorporation and active hyphal length), and carbon and nitrogen mineralization rates. We considered the microbial soil DNA as the microbial seedbank. High C/N ratio favored fungal presence, while low C/N favored dominance of bacterial populations. Our results suggest that organic amendments shape the soil microbial community structure through a feedback mechanism by which microbial activity responds to changing organic inputs and rearranges composition of the microbial seedbank. We hypothesize that the microbial seedbank composition responds to changing organic inputs according to the resistance and resilience of individual species, while changes in microbial activity may result in increases or decreases in availability of various soil nutrients that affect plant nutrient uptake. PMID:28198425

  14. Temporal variation of the total nitrogen concentration in aereal organs of nitrogen fixing and non fixing riparian species

    OpenAIRE

    Llinares, F.

    1992-01-01

    Changes in nitrogen concentration was determinated in samples of Alnus glutinosa, Elaeagnus angustifolia, Populus x canadiensis and Ailanthus altissima leaves, petioles and branches periodically during a year. Maximum nitrogen percentage was found in diazotrophic species (Alnus and Elaeagnus) and the nitrogen retranslocation form branches was higher (2.5 times) in no fixing species. Se estudian 10s cambios en la concentración de nitrógeno en Alnus glutinosa, Elaeagnus angustifolia, Populus...

  15. Reduction of nitrogen excretion and emission in poultry: A review for organic poultry.

    Science.gov (United States)

    Chalova, Vesela I; Kim, Jihyuk; Patterson, Paul H; Ricke, Steven C; Kim, Woo K

    2016-01-01

    Organic poultry is an alternative to conventional poultry which is rapidly developing as a response to customers' demand for better food and a cleaner environment. Although organic poultry manure can partially be utilized by organic horticultural producers, litter accumulation as well as excessive nitrogen still remains a challenge to maintain environment pureness, animal, and human health. Compared to conventional poultry, diet formulation without nitrogen overloading in organic poultry is even more complicated due to specific standards and regulations which limit the application of some supplements and imposes specific criteria to the ingredients in use. This is especially valid for methionine provision which supplementation as a crystalline form is only temporarily allowed. This review is focused on the utilization of various protein sources in the preparation of a diet composed of 100% organic ingredients which meet the avian physiology need for methionine, while avoiding protein overload. The potential to use unconventional protein sources such as invertebrates and microbial proteins to achieve optimal amino acid provision is also discussed.

  16. [Chlorination byproducts formation potentials of typical nitrogenous organic compounds in water].

    Science.gov (United States)

    Xu, Qian; Xu, Bin; Qin, Cao; Xia, Sheng-Ji; Gao, Nai-Yun; Tian, Fu-Xiang; Li, Da-Peng

    2011-07-01

    Twelve typical nitrogenous organic compounds including herbicides, pesticides, amino acids, industrial products etc in polluted raw water were selected to investigate formation of typical carbonaceous and nitrogenous DBPs during chlorination and chloramination. To indentify the formation mechanism of carbonaceous and nitrogenous disinfection byproducts from nitrogenous chemicals, chlorination and chloroamination of urea herbicides, triazine herbicides, amino acid, and other compounds were investigated. As a result, the potential precursors for different DBPs were defined as well. It has been identified that widely used urea herbicides could produce as many as 9 specific DBPs. The chlorotoluron shows highest reactivity and yields chloroform (CF), monochloroacetic acid (MCAA), dichloroacetic acid (DCAA), 1,1-dichloro-acetone (1,1-DCP), 1,1,1-trichloro-acetone (1,1,1-TCP), chloropicrin (NTCM), dichloro-acetonitrile (DCAN), dimethylnitrosamine (NDMA). The results indicated that aldicarb and dinoseb are important precursors of CF, DCAA, MCAA, NTCM as well. High concentrations of CF and DCAA were found during L-tryptophan chlorination. Furthermore, DBPs formation pathways and mechanisms were suggested during chlorination and chloramination of chlorotoluron, ametryn, dinoseb L-tryptophan.

  17. Exogenous nutrients and carbon resource change the responses of soil organic matter decomposition and nitrogen immobilization to nitrogen deposition.

    Science.gov (United States)

    He, Ping; Wan, Song-Ze; Fang, Xiang-Min; Wang, Fang-Chao; Chen, Fu-Sheng

    2016-03-29

    It is unclear whether exogenous nutrients and carbon (C) additions alter substrate immobilization to deposited nitrogen (N) during decomposition. In this study, we used laboratory microcosm experiments and (15)N isotope tracer techniques with five different treatments including N addition, N+non-N nutrients addition, N+C addition, N+non-N nutrients+C addition and control, to investigate the coupling effects of non-N nutrients, C addition and N deposition on forest floor decomposition in subtropical China. The results indicated that N deposition inhibited soil organic matter and litter decomposition by 66% and 38%, respectively. Soil immobilized (15)N following N addition was lowest among treatments. Litter (15)N immobilized following N addition was significantly higher and lower than that of combined treatments during the early and late decomposition stage, respectively. Both soil and litter extractable mineral N were lower in combined treatments than in N addition treatment. Since soil N immobilization and litter N release were respectively enhanced and inhibited with elevated non-N nutrient and C resources, it can be speculated that the N leaching due to N deposition decreases with increasing nutrient and C resources. This study should advance our understanding of how forests responds the elevated N deposition.

  18. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Montaña, José Salvador; Martínez, María Mercedes

    2011-01-01

    With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB) of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-

  19. [Response of black soil organic carbon, nitrogen and its availability to longterm fertilization].

    Science.gov (United States)

    Luo, Kun; Hu, Rong-Gui; Zhang, Wen-Ju; Zhou, Bao-Ku; Xu, Ming-Gang; Zhang, Jing-Ye; Xia, Ping-Ping

    2013-02-01

    Based on the long-term fertilization experiments, effects of various fertilization practices on the soil organic carbon (SOC) and total nitrogen (TN) in the surface (0-20 cm) and subsurface (20-40 cm) black soil in northeast China were studied. Results showed that, compared with the CK, long-term application of organic manure, especially the combination of mineral fertilizers and organic manure significantly increased the organic SOC and TN in the surface soil. Application of mineral fertilizers plus organic manure with conventional (NPM) and high application (N2P2M2) rate increased SOC significantly by 24. 6% and 25.1% , and TN by 29.5% and 32.8%, respectively. However, there was no significant difference among the treatments for SOC and TN at the subsurface. Compared with the CK (CKh), mineral fertilizer plus organic manure (NPM and N2P2M2) did not only increase the soil microbial biomass carbon (SMBC) and nitrogen (SMBN) , dissolved organic carbon (DOC) and nitrogen (DN), but also significantly increased the ratio of SMBC and DOC to SOC, SMBN and TN to TN. Application of the NPM and N2P2M2 increased the value of SMBC/SOC by 0.36 to 0.59 and SMBN/TN by 1.21 to 1.95 percentage points, respectively. The value of DOC/SOC and DN/TN ranged from 0.53% to 0.72% and 1.41% to 1.78%, respectively. This result indicated that SMBC, SMBN, DOC, DN and SMBC/ SOC, SMBN/TN, DOC/SOC, DN/TN were more sensitive than SOC and TN to long-term fertilization in the soil profile, and were better indicators for the impact of long-term fertilization soil fertility. The concluded that the application of manure especially manure plus mineral fertilizers can increase soil nutrients activity in the surface and subsurface black soil, acting as a helpful practice to improve soil fertility and the ability of nutrient supply, while it may cause potential environment pollution on carbon and nitrogen loss in the agroecosystem.

  20. Effect of biochar on leaching of organic carbon, nitrogen, and phosphorus from compost in bioretention systems.

    Science.gov (United States)

    Iqbal, Hamid; Garcia-Perez, Manuel; Flury, Markus

    2015-07-15

    Compost is used in bioretention systems to improve soil quality, water infiltration, and retention of contaminants. However, compost contains dissolved organic matter, nitrate, and phosphorus, all of which can leach out and potentially contaminate ground and surface waters. To reduce the leaching of nutrients and dissolved organic matter from compost, biochar may be mixed into the bioretention systems. Our objective was to test whether biochar and co-composted biochar mixed into mature compost can reduce the leaching of organic carbon, nitrogen, and phosphorus. There was no significant difference between the effects of biochar and co-composted biochar amendments on nutrient leaching. Further, biochar amendments did not significantly reduce the leaching of dissolved organic carbon, nitrate, and phosphorus as compared to the compost only treatment. The compost-sand mix was the most effective in reducing nitrate and phosphorus leaching among the media.

  1. Start-up and microbial communities of a simultaneous nitrogen removal system for high salinity and high nitrogen organic wastewater via heterotrophic nitrification.

    Science.gov (United States)

    Chen, Jiahao; Han, Yi; Wang, Yingmu; Gong, Benzhou; Zhou, Jian; Qing, Xiaoxia

    2016-09-01

    In this study, a simultaneous nitrogen removal system for high salinity and high nitrogen organic wastewater was developed in a pressurized biofilm reactor. The result showed that under the air supply rate of 200Lh(-1), salinity of 3.0±0.2%, organic load of 10kgCODm(-3)d(-1) and nitrogen loading of 0.185kgm(-3)d(-1), the reactor started up rapidly and performed stably after 30days operation. Meanwhile, a simultaneous COD and nitrogen removal was achieved in the single-stage reactor, with COD, NH4(+)-N and TN removal efficiency of 97%, 99% and 98%, respectively. Denaturing gradient gel electrophoresis profile demonstrated that simultaneous nitrogen removal could be achieved through heterotrophic nitrification-aerobic denitrification, and the pivotal microorganisms were Flavobacterium phragmitis and Paracoccus denitrificans. The microbial community of salt-tolerant halophilic microorganisms was developed successfully. This study can provide a more efficient and feasible solution to treat high salinity organic wastewater.

  2. Dialysis is superior to anion exchange for removal of dissolved inorganic nitrogen from freshwater samples prior to dissolved organic nitrogen determination

    DEFF Research Database (Denmark)

    Graeber, Daniel; Gücker, Björn; Zwirnmann, Elke;

    2012-01-01

    Dissolved organic nitrogen (DON) is usually determined as the difference between total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN). When applying this approach to samples with high DIN concentrations, there is a risk, that small relative errors in TDN and DIN measurements may...... propagate into high absolute errors of the determined DON concentration. To reduce such errors, two pretreatment methods have been suggested for the removal of DIN prior to the determination of DON: anion-exchange pretreatment (AEP) and dialysis pretreatment (DP). In this study, we tested the suitability...... of AEP and DP for DIN removal in order to increase DON determination accuracy of freshwater samples. The AEP pretreatment performed well for standard compounds, yielding high dissolved organic carbon (DOC) recovery rates and > 99% removal of nitrate, whereas DON recovery rates varied and no removal...

  3. Nitrogen-doped titanium dioxide photocatalysts for visible response prepared by using organic compounds

    Directory of Open Access Journals (Sweden)

    Yoshio Nosaka, Masami Matsushita, Junichi Nishino and Atsuko Y. Nosaka

    2005-01-01

    Full Text Available In order to utilize visible light in photocatalytic reactions, nitrogen atoms were doped in commercially available photocatalytic TiO2 powders by using an organic compound such as urea and guanidine. Analysis by X-ray photoelectron spectroscopy (XPS indicated that N atoms were incorporated into two different sites of the bulk phase of TiO2. A significant shift of the absorption edge to a lower energy and a higher absorption in the visible light region were observed. These N-doped TiO2 powders exhibited photocatalytic activity for the decomposition of 2-propanol in aqueous solution under visible light irradiation. The photocatalytic activity increased with the decrease of doped N atoms in O site, while decreased with decrease of the other sites. Degradation of photocatalytic activity based on the release of nitrogen atoms was observed for the reaction in the aqueous suspension system.

  4. Response of hydrolytic enzyme activities and nitrogen mineralization to fertilizer and organic matter application in subtropical paddy soils

    Science.gov (United States)

    Kader, Mohammed Abdul; Yeasmin, Sabina; Akter, Masuda; Sleutel, Steven

    2016-04-01

    Driving controllers of nitrogen (N) mineralization in paddy soils, especially under anaerobic soil conditions, remain elusive. The influence of exogenous organic matter (OM) and fertilizer application on the activities of five relevant enzymes (β-glucosaminidase, β-glucosidase, L-glutaminase, urease and arylamidase) was measured in two long-term field experiments. One 18-years field experiment was established on a weathered terrace soil with a rice-wheat crop rotation at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) having five OM treatments combined with two mineral N fertilizer levels. Another 30-years experiment was established on a young floodplain soil with rice-rice crop rotation at the Bangladesh Agricultural University (BAU) having eight mineral fertilizer treatments combined with organic manure. At BSMRAU, N fertilizer and OM amendments significantly increased all enzyme activities, suggesting them to be primarily determined by substrate availability. At BAU, non-responsiveness of β-glucosidase activity suggested little effect of the studied fertilizer and OM amendments on general soil microbial activity. Notwithstanding probably equal microbial demand for N, β-glucosaminidase and L-glutaminase activities differed significantly among the treatments (P>0.05) and followed strikingly opposite trends and correlations with soil organic N mineralization. So enzymatic pathways to acquire N differed by treatment at BAU, indicating differences in soil N quality and bio-availability. L-glutaminase activity was significantly positively correlated to the aerobic and anaerobic N mineralization rates at both field experiments. Combined with negative correlations between β-glucosaminidase activity and N mineralization rates, it appears that terminal amino acid NH2 hydrolysis was a rate-limiting step for soil N mineralization at BAU. Future investigations with joint quantification of polyphenol accumulation and binding of N, alongside an

  5. Measured and simulated nitrogen fluxes after field application of food-processing and municipal organic wastes.

    Science.gov (United States)

    Parnaudeau, V; Génermont, S; Hénault, C; Farrugia, A; Robert, P; Nicolardot, B

    2009-01-01

    The aims of this study were to (i) assess N fluxes (mineralization, volatilization, denitrification, leaching) caused by spreading various organic wastes from food-processing industries during a field experiment, and (ii) to identify the main factors affecting N transformation processes after field spreading. Experimental treatments including the spreading of six types of waste and a control soil were set up in August 2000 and studied for 22 mo under bare soil conditions. Ammonia and nitrous oxide emissions, and nitrogen mineralization were measured in experimental devices and extrapolated to field conditions or computed in calculation models. The ammonia emissions varied from 80 to 580 g kg(-1) NH4+-N applied, representing 0 to 90 g N kg(-1) total N applied. Under these meteorologically favorable conditions (dry and warm weather), waste pH was the main factor affecting volatilization rates. Cumulated N2O-N fluxes were estimated at 2 to 5 g kg(-1) total N applied, which was quite low due to the low soil water content during the experimental period; water-filled pore space (WFPS) was confirmed as the main factor affecting N2O fluxes. Nitrogen mineralization from wastes represented 126 to 723 g N kg(-1) organic N added from the incorporation date to 14 May 2001 and was not related to the organic C to organic N ratio of wastes. Nitrogen lost by leaching during the equivalent period ranged from 30 to 890 g kg(-1) total N applied. The highest values were obtained for wastes having the highest inorganic N content and mineralization rates.

  6. Microbial Nitrogen Cycling Associated with the Early Diagenesis of Organic Matter in Subseafloor Sediments

    Science.gov (United States)

    Zhao, R.

    2015-12-01

    The early diagenesis of organic matter is the major energy source of marine sedimentary biosphere and thus controls its population size; however, the vertical distribution of any functional groups along with the diagenesis of organic matter is remained unclear, especially for those microbes involved in nitrogen transformation which serve as a major control on the nitrogen flux between reservoirs. Here we investigated the vertical distributions of various functional groups in five sediment cores retrieved from Arctic Mid-Ocean Ridge (AMOR), with emphasis on the nitrifiers, denitrifiers and anaerobic ammonium oxidizing bacteria (anammox). We observed the clear geochemical zonation associated with organic matter diagenesis in the sediments based on the pore water profiles of oxygen, nitrate, ammonium, manganese and sulfate, with distinct geochemical transition zones at the boundaries of geochemical zones, including oxic-anoxic transition zone (OATZ) and nitrate-manganese reduction zone (NMTZ). Nitrate was produced in surface oxygenated sediments and nitrate consumption mainly took place at the NMTZ, splitted between re-oxidation of ammonium and manganese (II). Abundances of ammonia oxidizers, nitrite oxidizers, and denitrifiers, estimated through quantitative PCR targeting their respective functional genes, generally decrease with depth, but constantly elevated around the OATZ, NMTZ, and manganese-reduction zone as well. Anammox bacteria were only detected around the NMTZ where both nitrate/nitrite and ammonium are available. These depth profiles of functional groups were also confirmed by the community structure profiling by prokaryotic 16S rRNA gene tag pyrosequencing. Cell-specific rates of nitrification and denitrification, calculated from the bulk net reaction rates divided by functional group abundances, were similar to those values from oligotrophic sediments like North Pond and thus suggested that nitrifiers and denitirifiers populations were in maintenance

  7. Scaling of nitrogen and phosphorus across plant organs in shrubland biomes across Northern China.

    Science.gov (United States)

    Yang, Xian; Tang, Zhiyao; Ji, Chengjun; Liu, Hongyan; Ma, Wenhong; Mohhamot, Anwar; Shi, Zhaoyong; Sun, Wei; Wang, Tao; Wang, Xiangping; Wu, Xian; Yu, Shunli; Yue, Ming; Zheng, Chengyang

    2014-06-26

    Allocation of limiting resources, such as nutrients, is an important adaptation strategy for plants. Plants may allocate different nutrients within a specific organ or the same nutrient among different organs. In this study, we investigated the allocation strategies of nitrogen (N) and phosphorus (P) in leaves, stems and roots of 126 shrub species from 172 shrubland communities in Northern China using scaling analyses. Results showed that N and P have different scaling relationships among plant organs. The scaling relationships of N concentration across different plant organs tended to be allometric between leaves and non-leaf organs, and isometric between non-leaf organs. Whilst the scaling relationships of P concentration tended to be allometric between roots and non-root organs, and isometric between non-root organs. In arid environments, plant tend to have higher nutrient concentration in leaves at given root or stem nutrient concentration. Evolutionary history affected the scaling relationships of N concentration slightly, but not affected those of P concentration. Despite fairly consistent nutrients allocation strategies existed in independently evolving lineages, evolutionary history and environments still led to variations on these strategies.

  8. Effects of Long-Term Fertilization on Distribution of Organic Matters and Nitrogen in Cinnamon Soil Macro-Aggregates

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Soil samples collected from a 25-year long-term fertilizer experiment carried out on the Earth-cumulic-Orthic Anthrosols in semi-humid farmland ecological system, were used to study the distribution of soil organic matters, total nitrogen, nitrate nitrogen, and ammoniate nitrogen in different grades of soil macro-aggregates in order to study the effects of long-term application of organic manures in combination with chemical fertilizers. It is showed that the percentage of mass of the soil macro-aggregates with long-term application of fertilizers with sizes of 5-2 mm is increased compared with that of the samples with no fertilizer. It is easier to form lager size soil macro-aggregates by the long-term application of organic manures in combination with chemical fertilizers. The contents of organic matters, total nitrogen and nitrate nitrogen are all higher after treatments with different combinations of fertilizers, while there is a little effect on the contents of ammoniate nitrogen. The contents of organic matters, total nitrogen in the grades of soil macro-aggregates from the plough layers of the treated farmland exhibited significant difference. Moreover, the contents of organic matters and total nitrogen in the soil macro-aggregates with the size of 1-0.25 mm is the highest in all treated soil samples. The contents of nitrate nitrogen in soil macro-aggregates increased with the increasing of soil macro-aggregate size except those applied with chemical fertilizer and lower amount of corn stover. The results of correlation analysis revealed that there exists a significantly positive correlation between the percentage of mass of soil macro-aggregates with the size of 5-2 mm and the contents of organic matters, total nitrogen and nitrate nitrogen in the soil samples. However, the correlation between the percentage of mass of soil macro-aggregates with the size of 1-0.25 mm and the contents of total nitrogen and nitrate nitrogen is significantly negative. The

  9. Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

    Directory of Open Access Journals (Sweden)

    Judith Prommer

    Full Text Available Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

  10. The development of a new technical platform to measure soil organic nitrogen cycling processes by microbes

    Science.gov (United States)

    Hu, Yuntao; Richter, Andreas; Wanek, Wolfgang

    2016-04-01

    Soil organic matter (SOM) decomposition is one of the most important processes of the global nitrogen cycle, having strong implications on soil N availability, terrestrial carbon cycling and soil carbon sequestration. During SOM decomposition low-molecular weight organic nitrogen (LMWON) is released which can be taken up by microbes (and plants). The breakdown of high-molecular weight organic nitrogen (HMWON, e.g. proteins, peptidoglycan, chitin, nucleic acids) represents the bottleneck of soil HMWON decomposition and is performed by extracellular enzymes released mainly by soil microorganisms. Despite that, the current understanding of the controls of these processes is incomplete. The only way to measure gross decomposition rates of these polymers is to use isotope pool dilution (IPD) techniques. In IPD approaches the product pool is isotopically enriched (by e.g. 15N) and the isotope dilution of this pool is measured over time. We have pioneered an IPD for protein and cellulose depolymerization, but IPD approaches for other polymers, specifically for important microbial necromass components such as chitin (fungi) and peptidoglycan (bacteria), or nucleic acids have not yet been developed. Here we present a workflow based on a universally applicable technical platform that allows to estimate the gross depolymerization rate of SOM (HMWON) at the molecular level, using ultra high performance liquid chromatography/high resolution Orbitrap mass spectrometry (UPLC/HRMS) combined with IPD techniques. The necessary isotopically labeled organic polymers (chitin, peptidoglycan and others) are extracted from laboratory bacterial and fungal cultures grown in fully isotopically labeled nutrient media (15N, 13C or both). A purification scheme for the different polymers is currently established. Labeled potential decomposition products (e.g. amino sugars and muropeptides from peptidoglycan, amino sugars and chitooligosaccharides from chitin, nucleotides and nucleosides from

  11. Soil resource availability impacts microbial response to organic carbon and inorganic nitrogen inputs

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei-jian; W.ZHU; S.HU

    2005-01-01

    Impacts of newly added organic carbon (C) and inorganic nitrogen (N) on the microbial utilization of soil organic matter are important in determining the future C balance of terrestrial ecosystems. We examined microbial responses to cellulose and ammonium nitrate additions in three soils with very different C and N availability. These soils included an organic soil( 14.2% total organic C, with extremely high extractable N and low labile C), a forest soi1(4.7% total organic C, with high labile C and extremely low extractable N),and a grassland soil (1.6% total organic C, with low extractable N and labile C). While cellulose addition alone significantly enhanced microbial respiration and biomass C and N in the organic and grassland soils, it accelerated only the microbial respiration in the highly-N limited forest soil. These results indicated that when N was not limited, C addition enhanced soil respiration by stimulating both microbial growth and their metabolic activity. New C inputs lead to elevated C release in all three soils, and the magnitude of the enhancement was higher in the organic and grassland soils than the forest soil. The addition of cellulose plus N to the forest and grassland soils initially increased the microbial biomass and respiration rates, but decreased the rates as time progressed. Compared to cellulose addition alone,cellulose plus N additions increased the total C-released in the grassland soil, but not in the forest soil. The enhancement of total Creleased induced by C and N addition was less than 50% of the added-C in the forest soil after 96 d of incubation, in contrast to 87.5%and 89.0% in the organic and grassland soils. These results indicate that indigenous soil C and N availability substantially impacts the allocation of organic C for microbial biomass growth and/or respiration, potentially regulating the turnover rates of the new organic C inputs.

  12. Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture.

    Science.gov (United States)

    Grunert, Oliver; Reheul, Dirk; Van Labeke, Marie-Christine; Perneel, Maaike; Hernandez-Sanabria, Emma; Vlaeminck, Siegfried E; Boon, Nico

    2016-05-01

    Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated €15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture.

  13. Assessing the Influences of Urbanization On Dissolved Organic Nitrogen in Stormwater and a Receiving Stream

    Science.gov (United States)

    Lusk, M. G.; Toor, G.

    2013-12-01

    Nitrogen (N) is present in several forms in terrestrial and aquatic systems. In water bodies, N is present in inorganic (NH4, NO3) and organic (both dissolved and particulate) forms. Nitrogen carried via stormwater runoff or leaching from fertilized urban landscapes to water bodies can have detrimental effects on water quality because the inorganic N forms are readily available to phytoplankton. There is growing evidence that a part of the dissolved organic N (DON) may also be bioavailable to phytoplankton. DON in urban stormwater runoff, for example, has been shown to be highly bioavailable. The objective of this research is to characterize the sources and chemical fractionation of organic N in stormwater runoff from an urban residential neighborhood and in streamwater along an urban to rural gradient. We hypothesize that urban stormwater DON will be highly fractionated into labile low-molecular weight fractions and that streamwater DON will become increasingly bioavailable with increased urbanization because of shifts in vegetation patterns and hydrologic flowpaths. To test this hypothesis, we are collecting stormwater runoff from an urban neighborhood near Tampa, Florida and streamwater from both urban and rural sub-basins of the adjacent Alafia River.

  14. State factor relationships of dissolved organic carbon and nitrogen losses from unpolluted temperate forest watersheds

    Science.gov (United States)

    Perakis, S.S.; Hedin, L.O.

    2007-01-01

    We sampled 100 unpolluted, old-growth forested watersheds, divided among 13 separate study areas over 5 years in temperate southern Chile and Argentina, to evaluate relationships among dominant soil-forming state factors and dissolved carbon and nitrogen concentrations in watershed streams. These watersheds provide a unique opportunity to examine broad-scale controls over carbon (C) and nitrogen (N) biogeochemistry in the absence of significant human disturbance from chronic N deposition and land use change. Variations in the ratio dissolved organic carbon (DOC) to nitrogen (DON) in watershed streams differed by underlying soil parent material, with average C:N = 29 for watersheds underlain by volcanic ash and basalt versus C:N = 73 for sedimentary and metamorphic parent materials, consistent with stronger adsorption of low C:N hydrophobic materials by amorphous clays commonly associated with volcanic ash and basalt weathering. Mean annual precipitation was related positively to variations in both DOC (range: 0.2-9.7 mg C/L) and DON (range: 0.008-0.135 mg N/L) across study areas, suggesting that variations in water volume and concentration may act synergistically to influence C and N losses across dry to wet gradients in these forest ecosystems. Dominance of vegetation by broadleaf versus coniferous trees had negligible effects on organic C and N concentrations in comparison to abiotic factors. We conclude that precipitation volume and soil parent material are important controls over chemical losses of dissolved organic C and N from unpolluted temperate forest watersheds. Our results raise the possibility that biotic imprints on watershed C and N losses may be less pronounced in naturally N-poor forests than in areas impacted by land use change and chronic N deposition. Copyright 2007 by the American Geophysical Union.

  15. Isotopic patterns in caps and stipes in sporocarps reveal patterns of organic nitrogen use by ectomycorrhizal fungi

    Science.gov (United States)

    Hobbie, Erik; Ouimette, Andrew; Chen, Janet

    2016-04-01

    Current ecosystem models use inorganic nitrogen as the currency of nitrogen acquisition by plants. However, many trees may gain access to otherwise unavailable soil resources, such as soil organic nitrogen, through their symbioses with ectomycorrhizal fungi, and this pathway of nitrogen acquisition may therefore be important in understanding plant responses to environmental change. Different functional groups of ectomycorrhizal fungi vary in their ability to enzymatically access protein and other soil resources. Such fungal parameters as hyphal hydrophobicity, the presence of rhizomorphs (long-distance transport structures), and exploration strategies (e.g., short-distance versus long-distance, mat formation) correspond with how fungi interact with and explore the environment, and the proportions of different exploration types present will shift along environmental gradients such as nitrogen availability. Isotopic differences between caps and stipes may provide a means to test for organic nitrogen use, since caps and stipes differ in δ13C and δ15N as a result of variable proportions of protein and other classes of compounds, and protein should differ isotopically among de novo synthesis, litter sources, and soil sources. Here, we propose that (1) isotopic differences between caps and stipes could be related to organic nitrogen uptake and to the δ13C and δ15N values of different pools of soil-derived or de novo-synthesized amino acids; (2) these isotopic differences will reflect greater acquisition of soil-derived organic nitrogen by exploration types of greater enzymatic capabilities to degrade recalcitrant nitrogen forms, specifically long-distance, medium-distance fringe, and medium-distance mat exploration types. To test these hypotheses, we use a dataset of isotopic values, %N, and %C in 208 cap/stipe samples collected from Oregon, western USA. δ13C differences in caps and stipes in a multiple regression model had an adjusted r2 of 0.292 (p protein and

  16. Selective cleavage of phenolic tert-butyldimethylsilyl ethers using simple organic nitrogen bases

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Simple organic nitrogen bases,such as Et_3N,pyridine,DBU,etc.,were found to be convenient and useful reagents for deprotection of TBDMS groups on acidic hydroxyl groups.The efficiency of these bases has an apparent order:1°amine>2°amine>3°amine and aliphatic base>aromatic base.In aqueous DMSO and at room temperature,phenolic TBDMS ethers were removed selectively in the presence of alcoholic TBDMS ethers.And catalytic base can make these reactions complete.This method is high-yielding,fast,clean,safe and ...

  17. Stoichiometric deduction of activated sludge process for organic carbon and nitrogen removal

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-yong; ZOU Lian-pei

    2009-01-01

    The activated sludge process (ASP) is the most generally applied biological wastewater treatment method. The ASP for the removal of organic carbon and nitrogen can be looked as the combination of eight processes. In order to set up an ASP model, the stoichiometric coefficients should be deduced so that the stoichiometric matrix can be presented. The important assumptions and simplifications behind the model for ASP are enumerated. Using the matrix, mass balance equation and consistent units, the stoichiometric coefficients in the eight processes are exclusively deduced one by one.

  18. Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies.

    Science.gov (United States)

    Song, Haiou; Yao, Zhijian; Wang, Mengqiao; Wang, Jinnan; Zhu, Zhaolian; Li, Aimin

    2013-01-01

    The effects of dissolved organic matter (DOM) on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins. With the increase of gallic acid concentration from 0 to 400 mg/L, the adsorption amount of nitrate-nitrogen on the commercial resins, including D201, Purolite A 300 (A300) and Purolite A 520E (A520E), would significantly decrease. However, the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them.Compared to D201 and A300 resins, A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules, such as gallic acid and tannin acid at greater levels in aqueous solution. Attractively, the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Freundlich equations. The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations. In batch adsorption processes, nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time. The pseudo first- and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin. The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater.

  19. Sequestration of organic nitrogen in a paddy soil chronosequence as assessed by amino sugars molecular markers

    Science.gov (United States)

    Roth, Philipp; Lehndorff, E.; Cao, Z.; Amelung, W.

    2010-05-01

    Available nitrogen is a limiting factor in paddy rice systems due to ammonia volatilization, denitrification and stabilization in organic complexes. Soil organic nitrogen (SON) might therefore constitute a critical component of the nitrogen cycle in rice systems. The objective of this study was to elucidate the role of microorganisms for the sequestration of paddy N in organic forms. For this purpose we analyzed amino sugars as markers for the residues of bacteria and fungi in a chronosequence of soils that were used for paddy rice production for a period of 0 to 2000 years in the Hangzhou bay area in Southeast China. Within the soil profile, amino sugar concentrations were generally highest in the puddled Ap horizon and decreased with increasing depth along with organic carbon concentrations regardless of the time of rice cultivation. Nevertheless, a sharp increase of total amino sugar concentration from 0.1 g kg-1 to 0.3 g kg-1 was observed in the Ah horizon when comparing tidal wetland to salt marsh that had been impoldered 30 years ago, indicating an increasing importance of microbial residues in SON stabilization following the conversion of the semiaquatic marsh to a terrestrial system. With increased time of paddy rice cropping, amino sugar concentrations continued to increase up to a maximum of 2.1 g kg-1 after 300 years of paddy cultivation but declined again to 1 g kg-1 in soils with 700-2000 years history of cultivation despite increasing organic matter accumulation. Changes in the composition of the amino sugars were also most pronounced at initial stages of paddy rice management. The proportions of glucosamine (abundant in fungal chitin) decreased during the first 50 years of cultivation relative to mainly galactosamine (abundant in bacterial gums) and muramic acid (abundant in bacterial peptidoglycan), that remained at constantly low levels. At later stages of paddy rice cultivation, the ratios of glucosamine to galactosamine and to muramic acid re

  20. The import and export of organic nitrogen species at a Scottish ombrotrophic peatland

    Science.gov (United States)

    McKenzie, R. M.; Özel, M. Z.; Cape, J. N.; Drewer, J.; Dinsmore, K. J.; Nemitz, E.; Hamilton, J. F.; Sutton, M. A.; Gallagher, M. W.; Skiba, U.

    2015-01-01

    Dissolved organic nitrogen (DON) can contribute significantly to the overall nitrogen budget, but is not routinely measured in precipitation or stream water. In order to investigate the contribution of DON to deposition and export of N, precipitation, stream and soil water samples were collected from an ombrotrophic peatland and analysed for DON Over a two year period. In wet only deposition DON contributed up to 10% of the total dissolved nitrogen (TDN), 99% in soil water, and 75% in stream water. No correlations were observed between DIN and DON in precipitation stream water or soil water. DIN is an important source of nutrients and in ombrotrophic peatlands, is only deposited via precipitation. Too much nitrogen to a sensitive ecosystem can result in problems with the way in which it is processed, such as an increase in the export of N via nearby water bodies. It is therefore important to monitor N deposition and export. Precipitation DIN showed a loose seasonal pattern, with peak concentrations occurring between January and June, while DON concentrations tended to be lower in the winter months. Stream water DON and NH4+ showed no obvious seasonal pattern but NO3- showed larger concentrations in cooler months and the smallest during warmer months, with the exception of June and July 2010, when concentrations were high. Precipitation and stream DON was qualitatively analysed using GC × GC-NCD. Ten unique compounds were detected, of which only five could be identified: pyrrole, benzonitrile, dodecylamine, N-nitrosodipropylamine and decylamine. Five compounds were present in both precipitation and stream samples: pyrrole, benzonitrile and three unidentified compounds. A more detailed DON speciation may be used to identify sources and pathways of DON.

  1. The import and export of organic nitrogen species at a Scottish ombrotrophic peatland

    Directory of Open Access Journals (Sweden)

    R. M. McKenzie

    2015-01-01

    Full Text Available Dissolved organic nitrogen (DON can contribute significantly to the overall nitrogen budget, but is not routinely measured in precipitation or stream water. In order to investigate the contribution of DON to deposition and export of N, precipitation, stream and soil water samples were collected from an ombrotrophic peatland and analysed for DON Over a two year period. In wet only deposition DON contributed up to 10% of the total dissolved nitrogen (TDN, 99% in soil water, and 75% in stream water. No correlations were observed between DIN and DON in precipitation stream water or soil water. DIN is an important source of nutrients and in ombrotrophic peatlands, is only deposited via precipitation. Too much nitrogen to a sensitive ecosystem can result in problems with the way in which it is processed, such as an increase in the export of N via nearby water bodies. It is therefore important to monitor N deposition and export. Precipitation DIN showed a loose seasonal pattern, with peak concentrations occurring between January and June, while DON concentrations tended to be lower in the winter months. Stream water DON and NH4+ showed no obvious seasonal pattern but NO3- showed larger concentrations in cooler months and the smallest during warmer months, with the exception of June and July 2010, when concentrations were high. Precipitation and stream DON was qualitatively analysed using GC × GC-NCD. Ten unique compounds were detected, of which only five could be identified: pyrrole, benzonitrile, dodecylamine, N-nitrosodipropylamine and decylamine. Five compounds were present in both precipitation and stream samples: pyrrole, benzonitrile and three unidentified compounds. A more detailed DON speciation may be used to identify sources and pathways of DON.

  2. Performance evaluation of the UV/H2O2 process on selected nitrogenous organic compounds: reductions of organic contents vs. corresponding C-, N-DBPs formations.

    Science.gov (United States)

    Chen, Huei-Wen; Chen, Chia-Yang; Wang, Gen-Shuh

    2011-10-01

    The presence of various organic contaminants in water sources is of concern due to their direct threats to human health and potential to react with disinfectants to form carcinogenic byproducts including trihalomethanes, haloacetic acids and nitrosamines in finished water. This study applied both medium-pressure and low-pressure ultraviolet light coupled with hydrogen peroxide (UV/H2O2) to evaluate its efficacy for degradation of selected nitrogenous organic compounds and corresponding disinfection byproduct (DBP) formation. Six organic compounds were chosen as target precursors based on their nitrogen contents and molecular structures. The results showed that higher oxidation capacity resulted in better reduction of organic matters and DBP formation potentials (DBPFPs). However, insufficient contact time and oxidant doses could lead to a rise of DBPFPs in the early stages of UV/H2O2 reactions. A greater percentage removal was achieved for organic carbon than organic nitrogen after UV/H2O2 treatment, especially for compounds with complicated structure such as diltiazem. During the UV/H2O2 treatment, the intermediate products include tertiary amine, dimethyl amine (DMA) or DMA-like structures, which are N-nitrosodimethylamine (NDMA) precursors after chlorination or chloramination. Furthermore, it was observed that using dissolved organic nitrogen and DMA to predict NDMAFP could lead to biased conclusions because of the complex nature of nitrogenous matters in aqueous environments.

  3. Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers

    Science.gov (United States)

    Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

    2016-01-01

    Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further

  4. Organic nitrogen-driven stimulation of arbuscular mycorrhizal fungal hyphae correlates with abundance of ammonia oxidizers

    Directory of Open Access Journals (Sweden)

    Petra eBukovská

    2016-05-01

    Full Text Available Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass, while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples

  5. Isotopic disproportionation during hydrogen isotopic analysis of nitrogen-bearing organic compounds

    Science.gov (United States)

    Nair, Sreejesh; Geilmann, Heike; Coplen, Tyler B.; Qi, Haiping; Gehre, Matthias; Schimmelmann, Arndt; Brand, Willi A.

    2015-01-01

    Rationale High-precision hydrogen isotope ratio analysis of nitrogen-bearing organic materials using high-temperature conversion (HTC) techniques has proven troublesome in the past. Formation of reaction products other than molecular hydrogen (H2) has been suspected as a possible cause of incomplete H2 yield and hydrogen isotopic fractionation. Methods The classical HTC reactor setup and a modified version including elemental chromium, both operated at temperatures in excess of 1400 °C, have been compared using a selection of nitrogen-bearing organic compounds, including caffeine. A focus of the experiments was to avoid or suppress hydrogen cyanide (HCN) formation and to reach quantitative H2 yields. The technique also was optimized to provide acceptable sample throughput. Results The classical HTC reaction of a number of selected compounds exhibited H2 yields from 60 to 90 %. Yields close to 100 % were measured for the experiments with the chromium-enhanced reactor. The δ2H values also were substantially different between the two types of experiments. For the majority of the compounds studied, a highly significant relationship was observed between the amount of missing H2and the number of nitrogen atoms in the molecules, suggesting the pyrolytic formation of HCN as a byproduct. A similar linear relationship was found between the amount of missing H2 and the observed hydrogen isotopic result, reflecting isotopic fractionation. Conclusions The classical HTC technique to produce H2 from organic materials using high temperatures in the presence of glassy carbon is not suitable for nitrogen-bearing compounds. Adding chromium to the reaction zone improves the yield to 100 % in most cases. The initial formation of HCN is accompanied by a strong hydrogen isotope effect, with the observed hydrogen isotope results on H2 being substantially shifted to more negative δ2H values. The reaction can be understood as an initial disproportionation leading to H2 and HCN

  6. New approaches to improve the removal of dissolved organic matter and nitrogen in aquaculture

    DEFF Research Database (Denmark)

    von Ahnen, Mathis

    Reducing the environmental impact of aquaculture requires that waste treatment practices are further improved. Currently applied treatment technologies achieve good solids removal and nitrification. Yet discharge of nitrogen (N) and organic matter (OM) from fish farms is still often an important...... issue constraining aquaculture development, especially in sensitive areas. Possibilities for efficient end-of-pipe treatment exist for large intensive recirculating aquaculture systems (RAS), while smaller and especially the technically less advanced fish farms, struggle to reduce nutrient discharge...... methods for removing dissolved N and OM from aquaculture effluents of technically less advanced farms in particular. The work split in two parts. The first part focused on the turnover of dissolved N-compounds (Paper I) and dissolved organic matter (DOM) (Paper II) and in aerobic biofilters operated...

  7. Spatial distribution of soils determines export of nitrogen and dissolved organic carbon from an intensively managed agricultural landscape

    DEFF Research Database (Denmark)

    Wohlfart, T; Exbrayat, J-F; Schelde, Kirsten;

    2012-01-01

    catchment mainly consist of sandy soil types besides organic soils along the streams. The aim of the study was to characterise the relative influence of soil type and land use on stream water quality. Nine snapshot sampling campaigns were undertaken during the growing season of 2009. Total dissolved...... nitrogen (TDN), nitrate (NO3−), ammonium nitrogen and dissolved organic carbon (DOC) concentrations were measured, and dissolved organic nitrogen (DON) was calculated for each grabbed sample. Electrical conductivity, pH and flow velocity were measured during sampling. Statistical analyses showed......% to TDN. Multiple-linear regression analyses performed between chemical data and landscape characteristics showed a significant negative influence of organic soils on instream N concentrations and corresponding losses in spite of their overall minor share of the agricultural land (12.9%). On the other...

  8. UTILIZATION OF ORGANIC NITROGEN-SOURCES BY 2 PHYTOPLANKTON SPECIES AND A BACTERIAL ISOLATE IN PURE AND MIXED CULTURES

    NARCIS (Netherlands)

    IETSWAART, T; SCHNEIDER, PJ; PRINS, RA

    1994-01-01

    Algal production of dissolved organic carbon and the regeneration of nutrients from dissolved organic carbon by bacteria are important aspects of nutrient cycling in the sea, especially when inorganic nitrogen is limiting. Dissolved free amino acids are a major carbon source for bacteria and can be

  9. The chemical composition of organic nitrogen in marine rainwater and aerosols

    Science.gov (United States)

    Altieri, K. E.; Hastings, M. G.; Peters, A.; Sigman, D. M.

    2010-12-01

    The current state of knowledge on organic nitrogen in the atmosphere is very limited. Atmospheric water soluble organic nitrogen (WSON) is a subset of the complex water soluble organic matter measured in atmospheric aerosols and rainwater; as such, it impacts cloud condensation processes and aerosol chemical and optical properties. In marine and continental atmospheric deposition, the organic N fraction can be 20-80% of total N potentially influencing receiving ecosystems. Therefore, atmospheric WSON plays an important role in both atmospheric chemistry and the global biogeochemical N cycle. However, the sources (i.e., anthropogenic vs. terrestrial vs. marine), composition (e.g., reduced or oxidized N), potential connections to inorganic N (NO3- and NH4+), and spatio-temporal variability of atmospheric WSON are largely unknown. Samples were collected on or near the island of Bermuda (32.27°N, 64.87°W), which is located in the western North Atlantic and experiences seasonal changes in transport that allow for study of both anthropogenically and primarily marine influenced air masses. Rainwater samples (n=7) and aqueous extracted aerosol samples (n=4) were analyzed by positive ion ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to characterize the chemical composition of the water soluble organic N on a per compound level. We found ~ 800 N containing compounds in 8 compound classes. The CHON+ compound class contained the largest number of N compounds (~ 460). Compared to continental rainwater [Altieri et al., ES&T, 2009], the CHON+ compounds in the marine samples are as dominant in number, yet have less regular patterns and lower O:C ratios for comparable N:C ratios. In fact, average O:C ratios of all N containing compound classes were lower in the marine samples than in continental rainwater samples. No organosulfates or nitrooxy-organosulfates were detected in the marine samples, both of

  10. Can isotopic signatures reveal reactive nitrogen priming of soil organic matter decompostion ?

    Science.gov (United States)

    Hood-Nowotny, Rebecca; Msii Participants, Alter-Net

    2015-04-01

    The newest meta-data analyses and the model based hypotheses state that global soil C storage is controlled by microbial scale processes of fungal competition for available nitrogen (N). However, the details of these microbe-dependent feedback mechanisms on N and C dynamics in European soils are largely unknown and contentious. Given global trends of increasing atmospheric N deposition and the continuing use of inorganic N fertilizer, the function of soils as a carbon sink is potentially under threat. Therefore, further research is urgently required in order to be able to provide reliable information on soil microbial responses for predictive climate change models. Changes in nutrient status could result in a chain reaction of interacting microbial mechanisms which in turn could lead to the shifts in underlying ecosystem biogeochemical process rates. Recent meta-analysis has shown that plant fungal symbiont community structure, exerts a greater fundamental control over soil C storage than temperature, precipitation or net primary production. Based on the hypothesis that plant associated fungi effectively scavenge all available organic and inorganic N leaving little N for the growth of the free-living decomposer microbial community and preventing further breakdown of SOM To investigate these possible effects we have sampled natural grassland and forest soils across a trans European gradient (ALTER-net-MSII Network) which have received additional inputs of inorganic nitrogen for the last five years and studied the impacts of nitrogen on the concentrations and isotope ratios of bulk soil organic matter (SOM) in addition to particular organic matter (POM) fractions, as early indicators of SOM decomposition. Initial results suggest that isotope ratios combined with C:N ratios of SOM can be useful to tease out some underlying mechanisms of organic matter breakdown for example the impact of carbonate/pH on SOM decomposition. But more detailed analyses of specific soil

  11. Degradation dynamics and bioavailability of land-based dissolved organic nitrogen in the Bohai Sea: Linking experiment with modeling.

    Science.gov (United States)

    Li, Keqiang; Ma, Yunpeng; Dai, Aiquan; Wang, Xiulin

    2017-02-24

    Dissolved organic nitrogen (DON) is the major nitrogen form in the Bohai Sea. Land-based DON is released into the nitrogen pool and degraded by planktonic microbiota in coastal ocean. In this study, we evaluated the degradation of land-based DON, particularly its dynamics and bioavailability, in coastal water by linking experiment and modeling. Results showed that the degradation rate constant of DON from sewage treatment plant was significantly faster than those of other land-based sources (Pmodel in the Bohai Sea. In the model, large amounts of DIN were supplied from DON of Liao River than the other rivers because of prolonged flushing time in Liaodong Bay.

  12. Nitrogen mineralization of a loam soil supplemented with organic-inorganic amendments under laboratory incubation

    Directory of Open Access Journals (Sweden)

    M. Kaleem ABBASI

    2016-07-01

    Full Text Available The quantification of nitrogen (N supplying capacity of organic amendments applied to a soil is of immense importance to examine synchronization, N release capacity, and fertilizer values of these added materials. The aim of the present study was to determine the potential mineralization of separate and combined use of poultry manure (PM, wheat (Triticum aestivum L. straw residues (WSR, and urea N (UN applied to a loam soil and incubated periodically over 140 days period. Treatments included PM100, WSR100, PM50 + WSR50, UN100, UN50 + PM50, UN50 + WSR50, UN50 + PM25 + WSR25, and a control (unfertilized. Added amendments were applied on an N-equivalent basis at the rate of 200 mg N kg−1. Nitrogen supplying capacity of added materials was determined by measuring changes in total mineral N (ammonium-nitrogen and nitrate-nitrogen [NH4+–N + NO3––N] and accumulation of NO3––N over different incubation periods. Changes in soil organic matter content and total N concentration were also monitored during the study. Results indicated that added amendments released substantial N into the mineral N pool (net cumulative N mineralized [NCNM] ranged between 39 and 147 mg N kg−1, lowest in the WSR and highest in the UN50+PM50. Significant differences were observed among the amendments and the net inorganic N derived from a separate and combined use of PM was greater than the other treatments. Total inorganic N derived from PM increased from 2.3 mg kg−1 at d 1, to a maximum of 102 to 105 mg kg−1 at 63, 84 and 105 d after PM application. The values were further increase from 31.5 mg kg−1 at d 0 to a maximum of 165 mg kg−1 at d 49 in UN50 + PM50 treatment. The net cumulative N nitrified (NCNN varied between 16 and 126 mg kg−1, highest in UN50 + PM50 treatment. Soil amended with WSR100 showed negative values both for mineralization and nitrification until day 84, displaying net immobilization. On average, percentage conversion of added N into

  13. High-resolution nitrogen stable isotope sclerochronology of bivalve shell carbonate-bound organics

    Science.gov (United States)

    Gillikin, David P.; Lorrain, Anne; Jolivet, Aurélie; Kelemen, Zita; Chauvaud, Laurent; Bouillon, Steven

    2017-03-01

    Nitrogen stable isotope ratios (δ15N) of organic material have successfully been used to track food-web dynamics, nitrogen baselines, pollution, and nitrogen cycling. Extending the δ15N record back in time has not been straightforward due to a lack of suitable substrates in which δ15N records are faithfully preserved, thus sparking interest in utilizing skeletal carbonate-bound organic matter (CBOM) in mollusks, corals, and foraminifera. Here we test if calcite Pecten maximus shells from the Bay of Brest and the French continental shelf can be used as an archive of δ15N values over a large environmental gradient and at a high temporal resolution (approximately weekly). Bulk CBOM δ15N values from the growing tip of shells collected over a large nitrogen isotope gradient were strongly correlated with adductor muscle tissue δ15N values (R2 = 0.99, n = 6, p < 0.0001). We were able to achieve weekly resolution (on average) over the growing season from sclerochronological profiles of three shells, which showed large seasonal variations up to 3.4‰. However, there were also large inter-specimen differences (up to 2.5‰) between shells growing at the same time and location. Generally, high-resolution shell δ15N values follow soft-tissue δ15N values, but soft-tissues integrate more time, hence soft-tissue data are more time-averaged and smoothed. Museum-archived shells from the 1950s, 1965, and 1970s do not show a large difference in δ15N values through time despite expected increasing N loading to the Bay over this time, which could be due to anthropogenic N sources with contrasting values. Compiling shell CBOM δ15N data from several studies suggests that the offset between soft-tissue and shell δ15N values (Δtissue-shell) differs between calcite and aragonite shells. We hypothesize that this difference is caused by differences in amino acids used in constructing the different minerals, which should be specific to the CaCO3 polymorph being constructed. Future

  14. Study of nitrogen and organics removal in sequencing batch reactor (SBR) using hybrid media.

    Science.gov (United States)

    Thuan, Tran-Hung; Chung, Yun-Chul; Ahn, Dae-Hee

    2003-03-01

    The removal of nitrogen and organics in a sequencing batch reactor (SBR) using hybrid media were investigated in this work. The hybrid media was made by the use of polyurethane foam (PU) cubes and powdered activated carbon (PAC). The function of activated carbon of hybrid media was to offer a suitable active site, which was able to absorb organic substances and ammonia, as well as that of PU was to provide an appropriated surface onto which biomass could be attached and grown. A laboratory-scale moving-bed sequencing batch reactor (SBR) was used for investigating the efficiency of hybrid media. The removal of nitrogen and organics for synthetic wastewater (COD; 490-1,627 mg/L, NH4(+)-N; 180-210 mg/L) were evaluated at different COD/N ratio and different anoxic phase conditions, respectively. The system was operated with the organic loading rate (OLR) of 0.1, 0.16, 0.24, and 0.28 kg COD/m3 day, respectively. Each mode based on OLR was divided as the periods of 45 days of operation time, except for third mode that was operated during 30 days. After acclimatization period, effluent total COD concentrations slightly decreased and the removal efficiency of organics increased to about 90% (COD; 70 mg/L) after 60 days and achieved 98% (COD; 30 mg/L) at the end of experiments. The organics reduction seemed to be less affected by shock loading since high organic loads did not affect the removal efficiency. The NIH4(+)-N concentrations in effluent showed almost lower than 1 mg/L and NO3(-)-N concentrations were high (150 mg/L) during a very low C/N ratio (C/N=2). Over 90% of T-N removal efficiency (T-N; 16 mg/L) was obtained during the last 20 days of the operation after controlling the COD/N ratio (C/N=7). The mixing condition and COD/N ratio at anoxic phase were determined as a main operating factors. In future, the optimal operating conditions of SBR system with hybrid media will be investigated from the view of maintaining a sufficient biomass to the hybrid media under

  15. Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets.

    Science.gov (United States)

    Lee, Ben H; Mohr, Claudia; Lopez-Hilfiker, Felipe D; Lutz, Anna; Hallquist, Mattias; Lee, Lance; Romer, Paul; Cohen, Ronald C; Iyer, Siddharth; Kurtén, Theo; Hu, Weiwei; Day, Douglas A; Campuzano-Jost, Pedro; Jimenez, Jose L; Xu, Lu; Ng, Nga Lee; Guo, Hongyu; Weber, Rodney J; Wild, Robert J; Brown, Steven S; Koss, Abigail; de Gouw, Joost; Olson, Kevin; Goldstein, Allen H; Seco, Roger; Kim, Saewung; McAvey, Kevin; Shepson, Paul B; Starn, Tim; Baumann, Karsten; Edgerton, Eric S; Liu, Jiumeng; Shilling, John E; Miller, David O; Brune, William; Schobesberger, Siegfried; D'Ambro, Emma L; Thornton, Joel A

    2016-02-09

    Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas-particle equilibrium and (ii) have a short particle-phase lifetime (∼2-4 h). Such dynamic behavior has significant implications for the production and phase partitioning of pONs, organic aerosol mass, and reactive nitrogen speciation in a forested environment.

  16. Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

    Science.gov (United States)

    Mohr, Claudia; Lopez-Hilfiker, Felipe D.; Lutz, Anna; Hallquist, Mattias; Lee, Lance; Romer, Paul; Cohen, Ronald C.; Iyer, Siddharth; Kurtén, Theo; Hu, Weiwei; Day, Douglas A.; Campuzano-Jost, Pedro; Jimenez, Jose L.; Xu, Lu; Ng, Nga Lee; Guo, Hongyu; Weber, Rodney J.; Wild, Robert J.; Brown, Steven S.; Koss, Abigail; de Gouw, Joost; Olson, Kevin; Goldstein, Allen H.; Seco, Roger; Kim, Saewung; McAvey, Kevin; Shepson, Paul B.; Starn, Tim; Baumann, Karsten; Edgerton, Eric S.; Liu, Jiumeng; Shilling, John E.; Miller, David O.; Brune, William; Schobesberger, Siegfried; D'Ambro, Emma L.; Thornton, Joel A.

    2016-01-01

    Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas–particle equilibrium and (ii) have a short particle-phase lifetime (∼2–4 h). Such dynamic behavior has significant implications for the production and phase partitioning of pONs, organic aerosol mass, and reactive nitrogen speciation in a forested environment. PMID:26811465

  17. Tightly-Coupled Plant-Soil Nitrogen Cycling: Comparison of Organic Farms across an Agricultural Landscape.

    Science.gov (United States)

    Bowles, Timothy M; Hollander, Allan D; Steenwerth, Kerri; Jackson, Louise E

    2015-01-01

    How farming systems supply sufficient nitrogen (N) for high yields but with reduced N losses is a central challenge for reducing the tradeoffs often associated with N cycling in agriculture. Variability in soil organic matter and management of organic farms across an agricultural landscape may yield insights for improving N cycling and for evaluating novel indicators of N availability. We assessed yields, plant-soil N cycling, and root expression of N metabolism genes across a representative set of organic fields growing Roma-type tomatoes (Solanum lycopersicum L.) in an intensively-managed agricultural landscape in California, USA. The fields spanned a three-fold range of soil carbon (C) and N but had similar soil types, texture, and pH. Organic tomato yields ranged from 22.9 to 120.1 Mg ha-1 with a mean similar to the county average (86.1 Mg ha-1), which included mostly conventionally-grown tomatoes. Substantial variability in soil inorganic N concentrations, tomato N, and root gene expression indicated a range of possible tradeoffs between yields and potential for N losses across the fields. Fields showing evidence of tightly-coupled plant-soil N cycling, a desirable scenario in which high crop yields are supported by adequate N availability but low potential for N loss, had the highest total and labile soil C and N and received organic matter inputs with a range of N availability. In these fields, elevated expression of a key gene involved in root N assimilation, cytosolic glutamine synthetase GS1, confirmed that plant N assimilation was high even when inorganic N pools were low. Thus tightly-coupled N cycling occurred on several working organic farms. Novel combinations of N cycling indicators (i.e. inorganic N along with soil microbial activity and root gene expression for N assimilation) would support adaptive management for improved N cycling on organic as well as conventional farms, especially when plant-soil N cycling is rapid.

  18. Comparative genomic analysis of N2-fixing and non-N2-fixing Paenibacillus spp.: organization, evolution and expression of the nitrogen fixation genes.

    Directory of Open Access Journals (Sweden)

    Jian-Bo Xie

    2014-03-01

    Full Text Available We provide here a comparative genome analysis of 31 strains within the genus Paenibacillus including 11 new genomic sequences of N2-fixing strains. The heterogeneity of the 31 genomes (15 N2-fixing and 16 non-N2-fixing Paenibacillus strains was reflected in the large size of the shell genome, which makes up approximately 65.2% of the genes in pan genome. Large numbers of transposable elements might be related to the heterogeneity. We discovered that a minimal and compact nif cluster comprising nine genes nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV encoding Mo-nitrogenase is conserved in the 15 N2-fixing strains. The nif cluster is under control of a σ(70-depedent promoter and possesses a GlnR/TnrA-binding site in the promoter. Suf system encoding [Fe-S] cluster is highly conserved in N2-fixing and non-N2-fixing strains. Furthermore, we demonstrate that the nif cluster enabled Escherichia coli JM109 to fix nitrogen. Phylogeny of the concatenated NifHDK sequences indicates that Paenibacillus and Frankia are sister groups. Phylogeny of the concatenated 275 single-copy core genes suggests that the ancestral Paenibacillus did not fix nitrogen. The N2-fixing Paenibacillus strains were generated by acquiring the nif cluster via horizontal gene transfer (HGT from a source related to Frankia. During the history of evolution, the nif cluster was lost, producing some non-N2-fixing strains, and vnf encoding V-nitrogenase or anf encoding Fe-nitrogenase was acquired, causing further diversification of some strains. In addition, some N2-fixing strains have additional nif and nif-like genes which may result from gene duplications. The evolution of nitrogen fixation in Paenibacillus involves a mix of gain, loss, HGT and duplication of nif/anf/vnf genes. This study not only reveals the organization and distribution of nitrogen fixation genes in Paenibacillus, but also provides insight into the complex evolutionary history of nitrogen fixation.

  19. Comparative genomic analysis of N2-fixing and non-N2-fixing Paenibacillus spp.: organization, evolution and expression of the nitrogen fixation genes.

    Science.gov (United States)

    Xie, Jian-Bo; Du, Zhenglin; Bai, Lanqing; Tian, Changfu; Zhang, Yunzhi; Xie, Jiu-Yan; Wang, Tianshu; Liu, Xiaomeng; Chen, Xi; Cheng, Qi; Chen, Sanfeng; Li, Jilun

    2014-03-01

    We provide here a comparative genome analysis of 31 strains within the genus Paenibacillus including 11 new genomic sequences of N2-fixing strains. The heterogeneity of the 31 genomes (15 N2-fixing and 16 non-N2-fixing Paenibacillus strains) was reflected in the large size of the shell genome, which makes up approximately 65.2% of the genes in pan genome. Large numbers of transposable elements might be related to the heterogeneity. We discovered that a minimal and compact nif cluster comprising nine genes nifB, nifH, nifD, nifK, nifE, nifN, nifX, hesA and nifV encoding Mo-nitrogenase is conserved in the 15 N2-fixing strains. The nif cluster is under control of a σ(70)-depedent promoter and possesses a GlnR/TnrA-binding site in the promoter. Suf system encoding [Fe-S] cluster is highly conserved in N2-fixing and non-N2-fixing strains. Furthermore, we demonstrate that the nif cluster enabled Escherichia coli JM109 to fix nitrogen. Phylogeny of the concatenated NifHDK sequences indicates that Paenibacillus and Frankia are sister groups. Phylogeny of the concatenated 275 single-copy core genes suggests that the ancestral Paenibacillus did not fix nitrogen. The N2-fixing Paenibacillus strains were generated by acquiring the nif cluster via horizontal gene transfer (HGT) from a source related to Frankia. During the history of evolution, the nif cluster was lost, producing some non-N2-fixing strains, and vnf encoding V-nitrogenase or anf encoding Fe-nitrogenase was acquired, causing further diversification of some strains. In addition, some N2-fixing strains have additional nif and nif-like genes which may result from gene duplications. The evolution of nitrogen fixation in Paenibacillus involves a mix of gain, loss, HGT and duplication of nif/anf/vnf genes. This study not only reveals the organization and distribution of nitrogen fixation genes in Paenibacillus, but also provides insight into the complex evolutionary history of nitrogen fixation.

  20. Isotopic composition of carbonate-bound organic nitrogen in deep-sea scleractinian corals: A new window into past biogeochemical change

    Science.gov (United States)

    Wang, Xingchen T.; Prokopenko, Maria G.; Sigman, Daniel M.; Adkins, Jess F.; Robinson, Laura F.; Ren, Haojia; Oleynik, Sergey; Williams, Branwen; Haug, Gerald H.

    2014-08-01

    Over the last two decades, the skeletal remains of deep-sea corals have arisen as a geochemical archive of Pleistocene oceanographic change. Here we report the exploration of the isotopic composition of the carbonate-bound organic nitrogen (hereafter, CB-δ15N) in the deep-sea scleractinian coral Desmophyllum dianthus as a possible tool for reconstructing past changes in the ocean nitrogen cycle. The measurement protocol is adapted from a high-sensitivity method for foraminifera shell-bound δ15N. We explored the variability of CB-δ15N within specimens, among corals collected at different depths in a given ocean region, and among different ocean regions. Modern D. dianthus CB-δ15N is strongly correlated with the δ15N of N export as estimated from sediment traps, shallow subsurface nitrate, and surface sediments, suggesting that CB-δ15N is a reliable proxy for δ15N of N export. D. dianthus CB-δ15N is consistently 8-9‰ higher than δ15N of N export, indicating that D. dianthus acquires its nutrition primarily from suspended particulate organic matter (POM) that derives from sinking POM, not directly from sinking POM.

  1. [Effects of organic-inorganic mixed fertilizers on rice yield and nitrogen use efficiency].

    Science.gov (United States)

    Zhang, Xiao-li; Meng, Lin; Wang, Qiu-jun; Luo, Jia; Huang, Qi-wei; Xu, Yang-chun; Yang, Xing-ming; Shen, Qi-rong

    2009-03-01

    A field experiment was carried to study the effects of organic-inorganic mixed fertilizers on rice yield, nitrogen (N) use efficiency, soil N supply, and soil microbial diversity. Rapeseed cake compost (RCC), pig manure compost (PMC), and Chinese medicine residue compost (MRC) were mixed with chemical N, P and K fertilizers. All the treatments except CK received the same rate of N. The results showed that all N fertilizer application treatments had higher rice yield (7918.8-9449.2 kg x hm(-2)) than the control (6947.9 kg x hm(-2)). Compared with that of chemical fertilizers (CF) treatment (7918.8 kg x hm(-2)), the yield of the three organic-inorganic mixed fertilizers treatments ranged in 8532.0-9449.2 kg x hm(-2), and the increment was 7.7%-19.3%. Compared with treatment CF, the treatments of organic-inorganic mixed fertilizers were significantly higher in N accumulation, N transportation efficiency, N recovery rate, agronomic N use efficiency, and physiological N use efficiency. These mixed fertilizers treatments promoted rice N uptake and improved soil N supply, and thus, increased N use efficiency, compared with treatments CF and CK. Neighbor joining analysis indicated that soil bacterial communities in the five treatments could be classified into three categories, i.e., CF and CK, PMC and MRC, and RCC, implying that the application of exogenous organic materials could affect soil bacterial communities, while applying chemical fertilizers had little effect on them.

  2. Modeling downward particulate organic nitrogen flux from zooplankton ammonium regeneration in the northern Benguela

    Science.gov (United States)

    Fernández-Urruzola, I.; Osma, N.; Gómez, M.; Pollehne, F.; Postel, L.; Packard, T. T.

    2016-12-01

    The vertical fluxes of particulate organic matter play a crucial role in the distribution of nutrients throughout the oceans. Although they have been the focus of intensive research, little effort has been made to explore alternative approaches that quantify the particle export at a high spatial resolution. In this study, we assess the minimum nitrogen flux (FN) required to sustain the heterotrophic metabolism in the water column from ocean depth profiles of zooplankton NH4+ excretion (RNH4+). The reduction of RNH4+ as a function of depth was described by a power law fit, RNH4+ = (RNH4+)m (z /zm)b , whereby the b-value determines the net particulate nitrogen loss with increasing depth. Integrating these excretory functions from the base of the euphotic zone to the ocean bottom, we calculated FN at two stations located over the Namibian outer shelf. Estimates of FN (ranging between 0.52 and 1.14 mmol N m-2 d-1) were compared with the sinking fluxes of particles collected in sediment traps (0.15-1.01 mmol N m-2 d-1) 50 m over the seafloor. We found a reasonable agreement between the two approaches when fast-sinking particles dominated the ecosystem, but the FN was somewhat at odds with the measured gravitational flux during a low-sedimentation regime. Applying our conceptual model to the mesozooplankton RNH4+ we further constructed a section of FN along a cross-shelf transect at 20° S, and estimated the efficiency of the epipelagic ecosystem to retain nutrients. Finally, we address the impact of the active flux driven by the migrant mesozooplankton to the total nitrogen export. Depending on the sedimentation regime, the downward active flux (0.86 mmol N m-2 d-1 at 150 m) accounted for between 50 and 307% of the gravitational flux.

  3. Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ben H.; Mohr, Claudia; Lopez-Hilfiker, Felipe D.; Lutz, Anna; Hallquist, Mattias; Lee, Lance; Romer, Paul; Cohen, Ronald C.; Iyer, Siddharth; Kurtén, Theo; Hu, Weiwei; Day, Douglas A.; Campuzano-Jost, Pedro; Jimenez, Jose L.; Xu, Lu; Ng, Nga Lee; Guo, Hongyu; Weber, Rodney J.; Wild, Robert J.; Brown, Steven S.; Koss, Abigail; de Gouw, Joost; Olson, Kevin; Goldstein, Allen H.; Seco, Roger; Kim, Saewung; McAvey, Kevin; Shepson, Paul B.; Starn, Tim; Baumann, Karsten; Edgerton, Eric S.; Liu, Jiumeng; Shilling, John E.; Miller, David O.; Brune, William; Schobesberger, Siegfried; D' Ambro, Emma L.; Thornton, Joel A.

    2016-01-25

    Organic nitrates (ON = RONO2 + RO2NO2) are an important reservoir, if not sink, of atmospheric nitrogen oxides (NOx=NO+NO2). ON formed from isoprene oxidation alone are responsible for the export of 8 to 30% of anthropogenic NOx out of the U.S. continental boundary layer [Horowitz et al., 1998; Liang et al., 1998]. Regional NOx budgets and tropospheric ozone (O3) production, are therefore particularly sensitive to uncertainties in the yields and fates of ON [Beaver et al., 2012; Browne et al., 2013]. The yields implemented in modeling studies are determined from laboratory experiments in which only a few of the first generation gaseous ON or the total gas and particle-phase ON have been quantified [Perring et al., 2013 and references therein], while production of highly functionalized ON capable of strongly partitioning to the particle-phase have been inferred [Farmer et al., 2010; Ng et al., 2007; Nguyen et al., 2011; Perraud et al., 2012; Rollins et al., 2012], or directly measured [Ehn et al., 2014]. Addition of a nitrate (–ONO2) functional group to a hydrocarbon is estimated to lower the equilibrium saturation vapor pressure by 2.5 to 3 orders of magnitude [e.g. Capouet and Muller, 2006]. Thus, organic nitrate formation can potentially enhance particle-phase partitioning of hydrocarbons in regions with elevated levels of nitrogen oxides, contributing to secondary organic aerosol (SOA) formation [Ng et al., 2007]. There has, however, been no high time-resolved measurements of speciated ON in the particle-phase. We utilize a newly developed high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) using Iodide-adduct ionization [B H Lee et al., 2014a] with a filter inlet for gases and aerosols (FIGAERO) [Lopez-Hilfiker et al., 2014] that allows alternating in situ measurement of the molecular composition of gas and particle phases. We present observations of speciated ON in the particle-phase obtained during the 2013 Southern Oxidant

  4. Organic forms dominate hydrologic nitrogen export from a lowland tropical watershed.

    Science.gov (United States)

    Taylor, Philip G; Wieder, William R; Weintraub, Samantha; Cohen, Sagy; Cleveland, Cory C; Townsend, Alan R

    2015-05-01

    Observations of high dissolved inorganic nitrogen (DIN) concentrations in stream water have reinforced the notion that primary tropical rain forests cycle nitrogen (N) in relative excess compared to phosphorus. Here we test this notion by evaluating hydrologic N export from a small watershed on the Osa Peninsula, Costa Rica, where prior research has shown multiple indicators of conservative N cycling throughout the ecosystem. We repeatedly measured a host of factors known to influence N export for one year, including stream water chemistry and upslope litterfall, soil N availability and net N processing rates, and soil solution chemistry at the surface, 15- and 50-cm depths. Contrary to prevailing assumptions about the lowland N cycle, we find that dissolved organic nitrogen (DON) averaged 85% of dissolved N export for 48 of 52 consecutive weeks. For most of the year stream water nitrate (NO3-) export was very low, which reflected minimal net N processing and DIN leaching from upslope soils. Yet, for one month in the dry season, NO3- was the major component of N export due to a combination of low flows and upslope nitrification that concentrated NO3- in stream water. Particulate organic N (PON) export was much larger than dissolved forms at 14.6 kg N x ha(-1) x yr(-1), driven by soil erosion during storms. At this rate, PON export was slightly greater than estimated inputs from free-living N fixation and atmospheric N deposition, which suggests that erosion-driven PON export could constrain ecosystem level N stocks over longer timescales. This phenomenon is complimentary to the "DON leak" hypothesis, which postulates that the long-term accumulation of ecosystem N in unpolluted ecosystems is constrained by the export of organic N independently of biological N demand. Using an established global sediment generation model, we illustrate that PON erosion may be an important vector for N loss in tropical landscapes that are geomorphically active. This study supports an

  5. Energy saving processes for nitrogen removal in organic wastewater from food processing industries in Thailand.

    Science.gov (United States)

    Johansen, N H; Suksawad, N; Balslev, P

    2004-01-01

    Nitrogen removal from organic wastewater is becoming a demand in developed communities. The use of nitrite as intermediate in the treatment of wastewater has been largely ignored, but is actually a relevant energy saving process compared to conventional nitrification/denitrification using nitrate as intermediate. Full-scale results and pilot-scale results using this process are presented. The process needs some additional process considerations and process control to be utilized. Especially under tropical conditions the nitritation process will round easily, and it must be expected that many AS treatment plants in the food industry already produce NO2-N. This uncontrolled nitrogen conversion can be the main cause for sludge bulking problems. It is expected that sludge bulking problems in many cases can be solved just by changing the process control in order to run a more consequent nitritation. Theoretically this process will decrease the oxygen consumption for oxidation by 25% and the use of carbon source for the reduction will be decreased by 40% compared to the conventional process.

  6. Solubility Characteristics and Slow-Release Mechanism of Nitrogen from Organic-Inorganic Compound Coated Urea

    Directory of Open Access Journals (Sweden)

    Hongtao Zou

    2015-01-01

    Full Text Available A soil incubation method was used to investigate the solubility characteristics and slow-release mechanism of organic-inorganic compound coated urea at temperature of 10, 20, and 30°C. The membrane microstructure with and without incubation was tested via scanning electron microscopy (SEM. Slow release of nitrogen (N from different inorganic minerals was analysed by the activation energy from the nutrient solubility system. The rate of nitrogen solubility increased with temperature increasing. The first-order reaction kinetic equation described the solubility process of coated urea. The rate constant k also increased with temperature increasing. Moreover, the SEM images showed that the microstructure of the coating layer changed into a flocculent structure and the number of tiny pores and holes on the membrane surface increased significantly with temperature increasing, which increased N solubility rate. The Arrhenius equation indicated that activation energy was closely related to k during the solubility process; the activation energy was reduced with k rising, which resulted in N solubility rate increasing. Overall, the N solubility rate of coated urea was affected by temperature.

  7. Variations in dissolved organic nitrogen concentration in biofilters with different media during drinking water treatment.

    Science.gov (United States)

    Zhang, Huining; Zhang, Kefeng; Jin, Huixia; Gu, Li; Yu, Xin

    2015-11-01

    Dissolved organic nitrogen (DON) is potential precursor of disinfection byproducts (DBPs), especially nitrogenous DBPs. In this study, we investigated the impact of biofilters on DON concentration changes in a drinking water plant. A small pilot plant was constructed next to a sedimentation tank in a drinking water plant and included activated carbon, quartz sand, anthracite, and ceramsite biofilters. As the biofilter layer depth increased, the DON concentration first decreased and then increased, and the variation in DON concentration differed among the biofilters. In the activated carbon biofilter, the DON concentration was reduced by the largest amount in the first part of the column and increased by the largest amount in the second part of the column. The biomass in the activated carbon filter was less than that in the quartz sand filter in the upper column. The heterotrophic bacterial proportion among bacterial flora in the activated carbon biofilter was the largest, which might be due to the significant reduction in DON in the first part of the column. Overall, the results indicate that the DON concentration in biofiltered water can be controlled via the selection of appropriate biofilter media. We propose that a two-layer biofilter with activated carbon in the upper layer and another media type in the lower layer could best reduce the DON concentration.

  8. Benthic fluxes of dissolved organic nitrogen in the Lower St. Lawrence Estuary and implications for selective organic matter degradation

    Directory of Open Access Journals (Sweden)

    M. Alkhatib

    2013-05-01

    Full Text Available The distribution of dissolved organic nitrogen (DON and carbon (DOC in sediment pore waters was determined at nine locations along the St. Lawrence Estuary and in the Gulf of St. Lawrence. The study area is characterized by gradients in the sedimentary particulate organic matter (POM reactivity, bottom water oxygen concentrations, as well as benthic respiration rates. Based on pore water profiles we estimated the benthic diffusive fluxes of DON and DOC. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1. DON fluxes were positively correlated with sedimentary POM reactivity and sediment oxygen exposure time (OET, suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30% to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange. This result is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. The ratio of the DON to nitrate flux increased from 0.6 in the Lower Estuary to 1.5 in the Gulf. In contrast to DON, DOC fluxes did not show any significant spatial variation along the Laurentian Channel (LC between the Estuary and the Gulf (2100 ± 100μmol m−2 d−1, suggesting that production and consumption of labile DOC components proceed at similar rates, irrespective of the overall benthic characteristics and the reactivity of POM. As a consequence, the molar C/N ratio of dissolved organic matter (DOM in pore water and the overlying bottom water varied significantly along the transect, with lowest C/N in the Lower Estuary (5–6 and highest C/N (> 10 in the Gulf. We observed large differences between the C/N of pore water DOM with respect to POM, and the degree of

  9. Measurement and analysis of soil nitrogen and organic matter content using near-infrared spectroscopy techniques

    Institute of Scientific and Technical Information of China (English)

    HE Yong; SONG Hai-yan; PEREIRA Annia García; G(O)MEZ Antihus Hemández

    2005-01-01

    Near infrared reflectance (NIR) spectroscopy is as a rapid, convenient and simple nondestructive technique useful for quantifying several soil properties. This method was used to estimate nitrogen (N) and organic matter (OM) content in a soil of Zhejiang Province, Hangzhou County. A total of 125 soil samples were taken from the field. Ninety-five samples spectra were used during the calibration and cross validation stage. Thirty samples spectra were used to predict N and OM concentration. NIR spectra of these samples were correlated using partial least square regression. The regression coefficients between measured and predicted values of N and OM was 0.92 and 0.93, and SEP (standard error of prediction) were 3.28 and 0.06, respectively, which showed that NIR method had potential to accurately predict these constituents in this soil. The results showed that NIR spectroscopy could be a good tool for precision farming application.

  10. Simultaneous enhancement of organics and nitrogen removal in drinking water biofilm pretreatment system with reed addition.

    Science.gov (United States)

    Feng, Li-Juan; Zhu, Liang; Yang, Qi; Yang, Guang-Feng; Xu, Jian; Xu, Xiang-Yang

    2013-02-01

    A novel drinking water biofilm pretreatment process with reed addition was established for enhancement of simultaneously organics and nitrogen removal. Results showed that nitrate removal efficiency was positively related with the influent C/N ratio, reaching to 87.8±2.8% at the C/N ratio of 4.7. However, the predicted trichloromethane (THM) levels based on total organic carbon (TOC) and UV254 were high with the increase of influent C/N ratio. Combined with the pollutants removal performance and microbial community variation, an appropriate C/N ratio via reed addition was determined at 2.2 for the continuous biofilm reactor. With adjustment of hydraulic retention time (HRT), the highest of nitrate removal efficiency (74.2±1.4%) and organics utilization efficiency (0.63 mg NO3--N mg(-1)TOC) were achieved at an optimum HRT of 18 h, with both low effluent NO3--N (0.88±0.03 mg l(-1)) and TOC (2.86±0.67 mg l(-1)).

  11. Marine biogenic source of atmospheric organic nitrogen in the subtropical North Atlantic.

    Science.gov (United States)

    Altieri, Katye E; Fawcett, Sarah E; Peters, Andrew J; Sigman, Daniel M; Hastings, Meredith G

    2016-01-26

    Global models estimate that the anthropogenic component of atmospheric nitrogen (N) deposition to the ocean accounts for up to a third of the ocean's external N supply and 10% of anthropogenic CO2 uptake. However, there are few observational constraints from the marine atmospheric environment to validate these findings. Due to the paucity of atmospheric organic N data, the largest uncertainties related to atmospheric N deposition are the sources and cycling of organic N, which is 20-80% of total N deposition. We studied the concentration and chemical composition of rainwater and aerosol organic N collected on the island of Bermuda in the western North Atlantic Ocean over 18 mo. Here, we show that the water-soluble organic N concentration ([WSON]) in marine aerosol is strongly correlated with surface ocean primary productivity and wind speed, suggesting a marine biogenic source for aerosol WSON. The chemical composition of high-[WSON] aerosols also indicates a primary marine source. We find that the WSON in marine rain is compositionally different from that in concurrently collected aerosols, suggesting that in-cloud scavenging (as opposed to below-cloud "washout") is the main contributor to rain WSON. We conclude that anthropogenic activity is not a significant source of organic N to the marine atmosphere over the North Atlantic, despite downwind transport from large pollution sources in North America. This, in conjunction with previous work on ammonium and nitrate, leads to the conclusion that only 27% of total N deposition to the global ocean is anthropogenic, in contrast to the 80% estimated previously.

  12. Influence of nitrogen and phosphorus sources on mycorrhizal lettuces under organic farming

    Science.gov (United States)

    Scotti, Riccardo; Seguel, Alex; Cornejo, Pablo; Rao, Maria A.; Borie, Fernando

    2010-05-01

    Arbuscular mycorrhizal fungi (AMF) develop symbiotic associations with plants roots. These associations are very common in the natural environment and can provide a range of benefits to the host plant. AMF improve nutrition, enhance resistance to soil-borne pests and disease, increase resistance to drought and tolerance to heavy metals, and contribute to a better soil structure. However, agricultural intensive managements, such as the use of mineral fertilizes, pesticides, mouldboard tillage, monocultures and use of non-mycorrhizal crops, are detrimental to AMF. As a consequence, agroecosystems are impoverished in AMF and may not provide the full range of benefits to the crop. Organic farming systems may be less unfavourable to AMF because they exclude the use of water-soluble fertilisers and most pesticides, and generally they plan diverse crop rotations. The AMF develop the most common type of symbiosis in nature: about 90% of the plants are mycorrhizal and many agricultural crops are mycorrhizal. One of more mycorrhizal crops is lettuce, that is very widespread in intensive agricultural under greenhouse. Therefore, cultivated lettuce is know to be responsive to mycorrhizal colonization which can reach 80% of root length and contribute to phosphorus and nitrogen absorption by this plant specie. For this work four different lettuce cultivars (Romana, Milanesa, Grande Lagos and Escarola) were used to study mycorrhization under organic agricultural system, supplying compost from agricultural waste (1 kg m-2) as background fertilization for all plots, red guano as phosphorus source (75 U ha-1 and 150 U ha-1 of P2O5), lupine flour as nitrogen source (75 and 150 U/ha of N) and a combination of both. Lettuce plants were cultivated under greenhouse and after two months of growing, plants were harvested and dried and fresh weight of lettuce roots and shoots were evaluated. The number of spores, percentage of colonization, total mycelium and glomalin content were also

  13. Removal of Organic Matter and Ammonia Nitrogen in Azodicarbonamide Wastewater by a Combination of Power Ultrasound Radiation and Hydrogen Peroxide

    Institute of Scientific and Technical Information of China (English)

    李文军; 吴笛; 石鑫; 文利雄; 邵磊

    2012-01-01

    A simple and efficient sonochemical method was developed for the degradation of organic matter and ammonia nitrogen in azodicarbonamide wastewater.The effects of initial pH,ultrasound format and peripheral water level on the sonolysis of hydrazine,urea,COD and ammonia nitrogen were investigated.It is found that the initial pH has a significant influence on the degradation of hydrazine and ammonia nitrogen,whereas this impact to urea is relatively small.It also shows that a noticeable enhancement of ammonia nitrogen removal could be achieved in a proper intermittent ultrasound operation mode,i.e.,1/1 min on/off mode.The height difference between the periph-eral water level and the inner water level of the flask affects the efficiency of ultrasonic treatment as well.

  14. Organic carbon and nitrogen export from a tropical dam-impacted floodplain system

    Directory of Open Access Journals (Sweden)

    R. Zurbrügg

    2013-01-01

    Full Text Available Tropical floodplains play an important role in organic matter transport, storage, and transformation between headwaters and oceans. However, the fluxes and quality of organic carbon (OC and organic nitrogen (ON in tropical river-floodplain systems are not well constrained. We explored the quantity and characteristics of dissolved and particulate organic matter (DOM and POM, respectively in the Kafue River flowing through the Kafue Flats (Zambia, a tropical river-floodplain system in the Zambezi River basin. During the flooding season, > 80% of the Kafue River water passed through the floodplain, mobilizing large quantities of OC and ON, which resulted in a net export of 69–119 kg OC km−2 d−1 and 3.8–4.7 kg ON km−2 d−1, 80% of which was in the dissolved form. The elemental C : N ratio of ~ 20, the comparatively high δ13C values of −25‰ to −21‰, and its spectroscopic properties (excitation-emission matrices showed that DOM in the river was mainly of terrestrial origin. Despite a threefold increase in OC loads due to inputs from the floodplain, the characteristics of the riverine DOM remained relatively constant along the sampled 410-km river reach. This suggests that floodplain DOM displayed properties similar to those of DOM leaving the upstream reservoir and implied that the DOM produced in the reservoir was relatively short-lived. In contrast, the particulate fraction was 13C-depleted (−29‰ and had a C : N ratio of ~ 8, which indicated that POM originated from phytoplankton production in the reservoir and in the floodplain, rather than from plant debris or resuspended sediments. While the upstream dam had little effect on the DOM pool, terrestrial particles were retained, and POM from algal and microbial sources was released to the river. A nitrogen mass balance over the 2200 km2 flooded area revealed an annual deficit of 15 500–22 100 t N in

  15. Exceptionally high organic nitrogen concentrations in a semi-arid South Texas estuary susceptible to brown tide blooms

    Science.gov (United States)

    Wetz, Michael S.; Cira, Emily K.; Sterba-Boatwright, Blair; Montagna, Paul A.; Palmer, Terence A.; Hayes, Kenneth C.

    2017-03-01

    Studies of estuarine eutrophication have tended to focus on systems with continually flowing rivers, while little is known about estuaries from semi-arid/arid regions. Here we report results from an assessment of water quality conditions in Baffin Bay, Texas, a shallow (use. Chlorophyll a averaged 28-30 μg/l in Baffin Bay from 2003 to 2013 and total Kjeldahl nitrogen (TKN) concentrations were also very high (116-120 μM), with concentrations of both variables exceeding those of most other Texas estuaries by 2-5 fold. More recent field sampling (2013-2015) showed that dissolved organic nitrogen concentrations in Baffin Bay (62 ± 14 μM) were >2 fold higher than in three other Texas estuaries. In contrast, inorganic nitrogen (ammonium, nitrate) and phosphate concentrations were relatively low. Statistically significant long-term annual increases in chlorophyll a and salinity were observed in Baffin Bay, while long-term seasonal increases were observed for water temperature and TKN. Overall, Baffin Bay is displaying multiple symptoms of eutrophication, namely very high organic carbon, organic nitrogen and chlorophyll concentrations, as well as symptoms not quantified here such as fish kills and episodic hypoxia. Much of the increase in chlorophyll in Baffin Bay, at least since ∼1990, have coincided with blooms of the mixotrophic phytoplankton species, Aureoumbra lagunensis, which is thought to be favored under high proportions of organic to inorganic nitrogen. Thus the high and possibly increasing organic nitrogen concentrations, coupled with a long-term annual increase in salinity and a long-term seasonal increase in water temperature are likely to promote additional brown tide blooms in this system in the future.

  16. Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies

    Institute of Scientific and Technical Information of China (English)

    Haiou Song; Zhijian Yao; Mengqiao Wang; Jinnan Wang; Zhaolian Zhu; Aimin Li

    2013-01-01

    The effects of dissolved organic matter (DOM) on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins.With the increase of gallic acid concentration from 0 to 400 mg/L,the adsorption amount of nitrate-nitrogen on the commercial resins,including D201,Purolite A 300 (A300) and Purolite A 520E (A520E),would significantly decrease.However,the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them.Compared to D201 and A300 resins,A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules,such as gallic acid and tannin acid at greater levels in aqueous solution.Attractively,the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Freundlich equations.The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations.In batch adsorption processes,nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time.The pseudo first-and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin.The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater.

  17. Tightly-Coupled Plant-Soil Nitrogen Cycling: Comparison of Organic Farms across an Agricultural Landscape.

    Directory of Open Access Journals (Sweden)

    Timothy M Bowles

    Full Text Available How farming systems supply sufficient nitrogen (N for high yields but with reduced N losses is a central challenge for reducing the tradeoffs often associated with N cycling in agriculture. Variability in soil organic matter and management of organic farms across an agricultural landscape may yield insights for improving N cycling and for evaluating novel indicators of N availability. We assessed yields, plant-soil N cycling, and root expression of N metabolism genes across a representative set of organic fields growing Roma-type tomatoes (Solanum lycopersicum L. in an intensively-managed agricultural landscape in California, USA. The fields spanned a three-fold range of soil carbon (C and N but had similar soil types, texture, and pH. Organic tomato yields ranged from 22.9 to 120.1 Mg ha-1 with a mean similar to the county average (86.1 Mg ha-1, which included mostly conventionally-grown tomatoes. Substantial variability in soil inorganic N concentrations, tomato N, and root gene expression indicated a range of possible tradeoffs between yields and potential for N losses across the fields. Fields showing evidence of tightly-coupled plant-soil N cycling, a desirable scenario in which high crop yields are supported by adequate N availability but low potential for N loss, had the highest total and labile soil C and N and received organic matter inputs with a range of N availability. In these fields, elevated expression of a key gene involved in root N assimilation, cytosolic glutamine synthetase GS1, confirmed that plant N assimilation was high even when inorganic N pools were low. Thus tightly-coupled N cycling occurred on several working organic farms. Novel combinations of N cycling indicators (i.e. inorganic N along with soil microbial activity and root gene expression for N assimilation would support adaptive management for improved N cycling on organic as well as conventional farms, especially when plant-soil N cycling is rapid.

  18. [Impacts of Land Use Changes on Soil Light Fraction and Particulate Organic Carbon and Nitrogen in Jinyun Mountain].

    Science.gov (United States)

    Lei, Li-guo; Jiang, Chang-sheng; Hao, Qing-ju

    2015-07-01

    Four land types including the subtropical evergreen broad-leaved forest, sloping farmland, orchard and abandoned land were selected to collect soil samples from 0 to 60 cm depth at the same altitude of sunny slope in the Jinyun Mountain in this study. Soil light fraction organic carbon and nitrogen ( LFOC and LFON), and particulate organic carbon and nitrogen (POC and PON) were determined and the distribution ratios and C/N ratios were calculated. The results showed that the contents of LFOC and LFON decreased significantly by 71. 42% and 38. 46% after the forest was changed into sloping farmland (P 0. 05), while the contents of LFOC and LFON increased significantly by 3. 77 and 1. 38 times after the sloping farmland was changed into abandoned land (P organic carbon and nitrogen accumulation; on the contrary, sloping farmland was easy to lose soil labile carbon and nitrogen. The LFOC and LFON distribution ratios were significantly reduced by 31. 20% and 30. 08%, respectively after the forest was changed into the sloping farmland, and increased by 18. 74% and 20. 33% respectively after the forest was changed into the orchard. Nevertheless, the distribution ratios of LFOC and LFON were changed little by converting the forest into the sloping farmland and orchard. The distribution ratios of LFOC, LFON, POC and PON all increased significantly after the farmland was abandoned (P soil organic carbon and nitrogen was enhanced after forest reclamation, while reduced after the sloping farmland was abandoned. The ratios of carbon to nitrogen in soil organic matter, light fraction organic matter and particulate organic matter were in the order of abandoned land (12. 93) > forest (8. 53) > orchard (7. 52) > sloping farmland (4. 40), abandoned land (16. 32) > forest (14. 29) > orchard (11. 32) > sloping farmland (7. 60), abandoned land (23. 41) > sloping farmland (13. 85 ) > forest (10. 30) > orchard (9. 64), which indicated that the degree of organic nitrogen mineralization

  19. [Mechanisms for the increased fertilizer nitrogen use efficiency of rice in wheat-rice rotation system under combined application of inorganic and organic fertilizers].

    Science.gov (United States)

    Liu, Yi-Ren; Li, Xiang; Yu, Jie; Shen, Qi-Rong; Xu, Yang-Chun

    2012-01-01

    A pot experiment was conducted to study the effects of combined application of organic and inorganic fertilizers on the nitrogen uptake by rice and the nitrogen supply by soil in a wheat-rice rotation system, and approach the mechanisms for the increased fertilizer nitrogen use efficiency of rice under the combined fertilization from the viewpoint of microbiology. Comparing with applying inorganic fertilizers, combined application of organic and inorganic fertilizers decreased the soil microbial biomass carbon and nitrogen and soil mineral nitrogen contents before tillering stage, but increased them significantly from heading to filling stage. Under the combined fertilization, the dynamics of soil nitrogen supply matched best the dynamics of rice nitrogen uptake and utilization, which promoted the nitrogen accumulation in rice plant and the increase of rice yield and biomass, and increased the fertilizer nitrogen use efficiency of rice significantly. Combined application of inorganic and organic fertilizers also promoted the propagation of soil microbes, and consequently, more mineral nitrogen in soil was immobilized by the microbes at rice early growth stage, and the immobilized nitrogen was gradually released at the mid and late growth stages of rice, being able to better satisfy the nitrogen demand of rice in its various growth and development stages.

  20. Dissolved organic nitrogen in urban streams: Biodegradability and molecular composition studies.

    Science.gov (United States)

    Lusk, Mary G; Toor, Gurpal S

    2016-06-01

    A portion of the dissolved organic nitrogen (DON) is biodegradable in water bodies, yet our knowledge of the molecular composition and controls on biological reactivity of DON is limited. Our objective was to investigate the biodegradability and molecular composition of DON in streams that drain a gradient of 19-83% urban land use. Weekly sampling over 21 weeks suggested no significant relationship between urban land use and DON concentration. We then selected two streams that drain 28% and 83% urban land use to determine the biodegradability and molecular composition of the DON by coupling 5-day bioassay experiments with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Both urban streams contained a wide range of N-bearing biomolecular formulas and had >80% DON in lignin-like compounds, with only 5-7% labile DON. The labile DON consisted mostly of lipid-and protein-like structures with high H/C and low O/C values. Comparison of reactive formulas and formed counterparts during the bioassay experiments indicated a shift toward more oxygenated and less saturated N-bearing DON formulas due to the microbial degradation. Although there was a little net removal (5-7%) of organic-bound N over the 5-day bioassay, there was some change to the carbon skeleton of DON compounds. These results suggest that DON in urban streams contains a complex mixture of compounds such as lipids, proteins, and lignins of variable chemical structures and biodegradability.

  1. Adsorptive removal of nitrogen-containing compounds from fuel by metal-organic frameworks

    Institute of Scientific and Technical Information of China (English)

    Zhaoyang; Wang; Zhiguo; Sun; Linghao; Kong; Gang; Li

    2013-01-01

    The adsorptive denitrogenation from fuels over three metal-organic frameworks(MIL-96(Al),MIL-53(Al)and MIL-101(Cr))was studied by batch adsorption experiments.Four nitrogen-containing compounds(NCCs)pyridine,pyrrole,quinoline and indole were used as model NCCs in fuels to study the adsorption mechanism.The physicochemical properties of the adsorbents were characterized by XRD,N2physical adsorption,FT-IR spectrum and Hammett indicator method.The metal-organic frameworks(MOFs),especially the MIL-101(Cr)containing Lewis acid sites as well as high specific surface area,can adsorb large quantities of NCCs from fuels.In addition,the adsorptive capacity over MIL-101(Cr)will be different for NCCs with different basicity.The stronger basicity of the NCC is,the more it can be absorbed over MIL-101(Cr).Furthermore,pore size and shape also affect the adsorption capacity for a given adsorbate,which can be proved by the adsorption over MIL-53(Al)and MIL-96(Al).The pseudo-second-order kinetic model and Langmuir equation can be used to describe kinetics and thermodynamics of the adsorption process,respectively.Finally,the regeneration of the used adsorbent has been conducted successfully by just washing it with ethanol.

  2. Mild and Moderate Extraction Methods to Assess Potentially Available Soil Organic Nitrogen

    Directory of Open Access Journals (Sweden)

    Bruno Boscov Braos

    Full Text Available ABSTRACT The use of chemical methods to assess the soil organic nitrogen (N potentially available to plants is not a common practice in Brazil. However, associated with others, this tool might improve efficiency in the use of waste and nitrogen fertilizers. In our study, chemical methods were tested to assess potentially available soil N in samples of 17 representative soils of the western plateau of the state of São Paulo (10 Oxisols and 7 Ultisols. Available soil N was extracted from the collected soil samples using moderate (ISNT-Illinois Soil Nitrogen Test and mild (hot water and heated solutions of 2 mol L-1 KCl and 0.01 mol L-1 CaCl2 extraction methods. The levels of potentially available N obtained from these chemical methods were correlated with dry matter (DM and N uptake (Nup by corn plants grown in pots in a greenhouse experiment carried out with the same 17 soil samples. The ISNT method showed the highest available N extraction capacity, whereas hot water showed the lowest capacity, followed closely by the hot 0.01 mol L-1 CaCl2 solution. Despite the differences among the quantities of available N extracted, the methods correlated with each other and with DM and Nup, but the values from the ISNT method showed the lowest correlation with plant variables (rDM = 0.67** and rNup = 0.81**. Procedures of extraction with water or 0.01 mol L-1 CaCl2 heated for 16 h, and 2 mol L-1 KCl heated for 4 h, resulted in similar correlation values (r with plant DM and Nup. Thus, water (rDM = 0.77** and rNup = 0.90** and 0.01 mol L-1 CaCl2 (rDM = 0.82** and rNup = 0.93** heated for 16 h can be recommended as the best options for N extraction.considering the possibility for predicting N availability, lower generation of waste, and lower cost of analysis.

  3. Organic matter and concentrated nitrogen removal by shortcut nitrification and denitrification from mature municipal landfill leachate

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-jun; PENG Yong-zhen; WANG Shu-ying; ZHENG Shu-wen; GUO Jin

    2007-01-01

    An UASB+Anoxic/Oxic (A/O) system was introduced to treat a mature landfill leachate with low carbon-to-nitrogen ratio and high ammonia concentration. To make the best use of the biodegradable COD in the leachate, the denitrification of NOx-N in the recirculation effluent from the clarifier was carried out in the UASB. The results showed that most biodegradable organic matters were removed by the denitrification in the UASB. The NH4+-N loading rate (ALR) of A/O reactor and operational temperature was 0.28-0.60 kg NH4+-N/(m3·d) and 17-29℃ during experimental period, respectively. The short-cut nitrification with nitrite accumulation efficiency of 90%-99% was stabilized during the whole experiment. The NH4+-N removal efficiency varied between 90% and 100%. When ALR was less than 0.45 kg NH4+-N/(m3·d), the NH4+-N removal efficiency was more than 98%. With the influent NH4+-N of 1200-1800 mg/L, the effluent NH4+-N was less than 15 mg/L. The shortcut nitrification and denitrification can save 40% carbon source, with a highly efficient denitrification taking place in the UASB. When the ratio of the feed COD to feed NH4+-N was only 2-3, the total inorganic nitrogen (TIN) removal efficiency attained 67%-80%. Besides, the sludge samples from A/O reactor were analyzed using FISH. The FISH analysis revealed that ammonia oxidation bacteria (AOB) accounted for 4% of the total eubacterial population, whereas nitrite oxidation bacteria (NOB) accounted only for 0.2% of the total eubacterial population.

  4. Determination of ammonium and organic bound nitrogen by inductively coupled plasma emission spectroscopy.

    Science.gov (United States)

    Jaber, A M Y; Mehanna, N A; Sultan, S M

    2009-06-15

    The continuous flow sample introduction technique with a hydride generator system in conjunction with an inductively coupled plasma emission spectrometer (ICP-AES-HG), is used in this study for quantitative determination of ammonium and organic bound nitrogen in aqueous and solid samples. Ammonia vapor released from ammonium salt after treatment with concentrated NaOH is transferred by argon to plasma for detection at 174.273 nm using axial argon plasma mode. The calibration curves were linear within a range of 25-1000 mg L(-1)N as ammonium molybdate with correlation coefficients of better than 0.99 and limits of detection of about 10-25mg L(-1)N. The percent recovery of N (25-500 mg L(-1)N) in soft (distilled) water and high salt content (1.7 mol L(-1) NaCl) matrices was found to be in the range of about 97-102% with %RSD in the range of 4.6-0.62. The sensitivity, limit of detection, and blank contribution from the atmospheric nitrogen, were tremendously improved in this method compared with the available ICP-AES spray chamber counterpart. Furthermore, the ICP-AES-HG method gave results for real samples (soil, fertilizer, waste water) containing about 50-1800 mg L(-1)N in good agreement with those obtained by the standard Kjeldahl method. No statistical differences at the 95% confidence level on applying the t-test were observed between the values obtained by the two methods. Thus, the ICP-AES-HG method is reliable and faster than the conventional tedious Kjeldahl method, superior to the ICP-AES spray chamber method, and almost free from matrix interference which is usually a critical factor in atomic emission spectroscopic techniques.

  5. Effects of supplemental organic cobalt on nutrient digestion and nitrogen balance in lambs fed forage-based diets

    Science.gov (United States)

    The objective of this study was to determine the effects of supplemental organic cobalt on nutrient digestion and nitrogen balance in lambs fed forage-based diets. Sixteen wether lambs (avg initial BW = 28.6 ± 1.3 kg) were used in a 2 × 2 Latin square and randomly allotted to one of two treatments b...

  6. Acquired phototrophy in Mesodinium and Dinophysis – A review of cellular organization, prey selectivity, nutrient uptake and bioenergetics

    DEFF Research Database (Denmark)

    Hansen, Per Juel; Nielsen, Lasse Tor; Johnson, Matthew;

    2013-01-01

    Acquired phototrophy, i.e. the use of chloroplasts from ingested prey, can be found among some species of dinoflagellates and ciliates. The best studied examples of this phenomenon in these groups are within the ciliate genus Mesodinium and the dinoflagellate genus Dinophysis, both ecologically i...... growth. Both Mesodinium and Dinophysis spp. can survive for months in the light without food. The potential role for modeling in exploring the complex balance of phototrophy and phago-heterotrophy, and its ecological implications for the mixotroph and their prey, is discussed....

  7. Synergy and Transition of Recovery Efficiency of Nitrogen Fertilizer in Various Rice Genotypes under Organic Farming

    Directory of Open Access Journals (Sweden)

    Lifen Huang

    2016-08-01

    Full Text Available Despite the growing demand for organic products, research on organic farming (OF such as genotype screening, fertilizer application and nutrition uptake remains limited. This study focused on comparisons of the apparent recovery efficiency of nitrogen fertilizer (REN in rice grown under OF and conventional farming (CF. Thirty-two representative conventional Japonica rice varieties were field grown under five different treatments: control check (CK; organic farming with low, medium and high levels of organic fertilizer (LO, MO and HO, respectively; and CF. Comparisons of REN between OF and CF classified the 32 genotypes into four types: high REN under both OF and CF (type-A; high REN under OF and low REN under CF (type-B; low REN under OF and high REN under CF (type-C; and low REN under both OF and CF (type-D. Though the yield and REN of all the rice varieties were higher with CF than with OF, organic N efficient type-A and B were able to maintain relatively high grain yield under OF. Physiological activities in flag leaves of the four types from booting to maturity were subsequently investigated under OF and CF. Under OF, high values of soil and plant analyzer development (SPAD and N were observed in type-B varieties, while in contrast, both indexes slowly decreased in type-C varieties under CF. Moreover, the decline in N content in type-C and D varieties was greater under OF than CF. The decrease in glutamine synthetase (GS, glutamic-pyruvic transaminase (GPT and glutamic oxaloacetic transaminase (GOT activity in flag leaves was smaller under OF than CF in type-A and B varieties, while in contrast, type-C and D varieties showed an opposite trend. The findings suggest that OF slows the decline in key enzymes of N metabolism in organic N-efficient type rice, thus maintaining a relatively high capacity for N uptake and utilization and increasing yield during the late growth period. Accordingly, we were able to screen for varieties of rice with

  8. [Effects of Different Land Uses on Soil Active Organic Carbon and Nitrogen Fractions in Jinyun Mountain].

    Science.gov (United States)

    Qi, Xin; Jiang, Chang-sheng; Hao, Qing-ju; Li, Jian-lin

    2015-10-01

    In this paper, we take Jinyun Mountain where located in Beibei district of Chongqing as the research object and explore the effect of different ways of land use on soil active organic carbon, nitrogen components by collecting the soil samples from 0 to 60 cm depth in subtropical evergreen broad-leaved forest (hereinafter referred to as the forest), abandoned land, orchard, farmland and measuring the content of MBC, MBN, DOC and DON. The research results show that the contents of soil MBC, MBN, DOC, DON are reduced with the increase of soil depth in four types of land using soils. Variance analysis of the single factor shows that four kinds of land uses have no significant difference in the contents of MBC, MBN and DON, but the DOC content of the abandoned land is significantly higher than that of other three kinds. It shows that the different ways of land use have no obvious effects on soil MBC, MBN and DON but the abandonment of slope cropland can significantly increase the content of soil DOC. There is no significant difference among the distribution ratio of MBN, DOC, DON in forest, abandoned land, orchard and farmland within the soil from 0 to 60 cm, but the distribution ratio of slope MBC is significantly higher than that of other three kinds. It means farmland soil organic carbon has a higher biological activity, this could due to the application of green manure, farmland manure and other organic fertilizers. Under different land utilizations, DOC/DON is the highest, MBC/MBN is the second, and SOC/TN is the lowest. It means the biological solidification of dissolved organic matter is the strongest, and the mineralization of soil organic matter is the most obvious. Under the four kinds of land uses, there are the lowest ratios in SOC/TN, MBC/MBN and DOC/DON in the farmland. And all the ratios are less than 20, which suggest that the mineralization of farmland soil organic matter is stronger and it's easy to cause the loss of soil carbon.

  9. Dissolved organic carbon and nitrogen leaching from Scots pine, Norway spruce and silver birch stands in southern Sweden

    OpenAIRE

    Fröberg, Mats; Hansson, Karna; Kleja, Dan Berggren; Alavi, Ghasem

    2011-01-01

    The effects of three common tree species – Scots pine, Norway spruce and silver birch – on leaching of dissolved organic carbon and dissolved nitrogen were studied in an experimental forest with podzolised soils in southern Sweden. We analyzed soil water collected with lysimeters and modeled water fluxes to estimate dissolved C and N fluxes. Specific UV absorbance (SUVA) was analyzed to get information about the quality of dissolved organic matter leached from the different stands. Under the ...

  10. Acquired blepharoptosis

    NARCIS (Netherlands)

    Oosterhuis, HJGH

    1996-01-01

    A review is given of the aetiology and possible treatment of acquired (non-congenital) blepharoptosis, which is a common but not specific sign of neurological disease: The diagnostic categories of upper eyelid drooping are scheduled as (a) pseudo-ptosis due to a local process or overactivity of eye

  11. Chemiluminescent method for detection of eutrophication sources by estimation of organic amino nitrogen and ammonium in water.

    Science.gov (United States)

    Meseguer-Lloret, S; Molins-Legua, C; Verdú-Andrés, J; Campíns-Falcó, P

    2006-11-01

    An automatic method has been developed for the estimation of organic amino nitrogen (CH2-NH) and ammonium in water samples. We propose a continuous flow system in which nitrogen compounds react with hypochlorite reagent to produce chloramines. Subsequently, the mixture is mixed with luminol, generating a chemiluminescence signal. The signal emission at 425 nm, registered as a function of time, decreases as nitrogen concentration increases, due to the decrease on hypochlorite concentration. A large number of nitrogen compounds have been assayed and their sensitivities compared, in milligrams per liter nitrogen. The ammonium calibration graph, expressed as N, can be used for most of the assayed compounds. The linear interval was 0.24-4 mg L(-1) N, with the detection limit 0.07 mg L(-1) N. The chemiluminescence method was applied to the analysis of several kinds of real water samples, natural, lake, irrigation ditch, fountain, residual, and seawater in order to detect possible sources of eutrophication. The accuracy (% relative error) and precision were satisfactory, with mean values of 5 +/- 4 and 3 +/- 2, respectively. This procedure has been used to estimate nitrogen content in samples before and after Kjeldahl treatment. In the same samples, the N found for the untreated samples provided a good estimation of the N Kjeldahl. Sixty samples per hour can be analyzed, and the procedure can also be used for in situ monitoring.

  12. An advanced technique for speciation of organic nitrogen in atmospheric aerosols

    Science.gov (United States)

    Samy, S.; Robinson, J.; Hays, M. D.

    2011-12-01

    The chemical composition of organic nitrogen (ON) in the environment is a research topic of broad significance. The topic intersects the branches of atmospheric, aquatic, and ecological science; thus, a variety of instrumentation, analytical methods, and data interpretation tools have evolved for determination of ON. Recent studies that focus on atmospheric particulate nitrogen (N) suggest a significant fraction (20-80%) of total N is bound in organic compounds. The sources, bioavailability and transport mechanisms of these N-containing compounds can differ, producing a variety of environmental consequences. Amino acids (AA) are a key class of atmospheric ON compounds that can contribute to secondary organic aerosol (SOA) formation and potentially influence water cycles, air pollutant scavenging, and the radiation balance. AA are water-soluble organic compounds (WSOC) that can significantly alter the acid-base chemistry of aerosols, and may explain the buffering capacity that impacts heterogeneous atmospheric chemistry. The chemical transformations that N-containing organic compounds (including AA) undergo can increase the light-absorbing capacity of atmospheric carbon via formation of 'brown carbon'. Suggested sources of atmospheric AA include: marine surface layer transport from bursting sea bubbles, the suspension of bacteria, fungi, algae, pollen, spores, or biomass burning. Methodology for detection of native (underivatized) amino acids (AA) in atmospheric aerosols has been developed and validated (Samy et al., 2011). This presentation describes the use of LC-MS (Q-TOF) and microwave-assisted gas phase hydrolysis for detection of free and combined amino acids in aerosols collected in a Southeastern U.S. forest environment. Accurate mass detection and the addition of isotopically labeled surrogates prior to sample preparation allows for sensitive quantitation of target AA in a complex aerosol matrix. A total of 16 native AA were detected above the reporting

  13. Carbon mineralisation in litter and soil organic matter in forests with different nitrogen status

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Patrik

    2000-07-01

    The objective of this thesis was to investigate the effect of both organic and inorganic nitrogen (N) on carbon (C) mineralisation of litter and soil organic matter, in order to increase the understanding of factors affecting decomposition and, ultimately, soil C sequestration. Fresh recently fallen needle litter with three contrasting total N concentrations were sampled, along with litter, humus and mineral soil layers from coniferous and deciduous forest sites in Europe. The sampled substrates were incubated in the laboratory at constant temperature (15 deg C) and near-optimal moisture. The fresh needles further received additions of ammonium and nitrate. Initial C mineralisation rates were higher in fresh N-rich needles than in fresh N-poor needles. However, after a 559-day incubation at 15 deg C cumulative C mineralisation was lower in the fresh N-rich needles than in the fresh N-poor needles. Negative effects of high N on C mineralisation were also found in litter and humus layers in the European forests and at sites with N-fertilisation trials, where low C mineralisation rates were associated with high total N concentrations. During early stages of decomposition, addition of ammonium and nitrate to fresh needles did not increase cumulative C mineralisation, suggesting that the decomposing organisms were not limited by low N supply even in the low-N needles. The initially higher C mineralisation in N-rich compared with N-poor needles is suggested to be a consequence of higher C quality in the N-rich substrates. In later stages of decomposition, the question why N seemed to have a negative effect on decomposition could not be satisfactorily answered, although there were indications that recalcitrant N-containing compounds were formed in fresh needles with high N concentration. This thesis presents some probable explanations of the negative effect on decomposition of high N.

  14. [Effects of long-term fertilization on soil organic nitrogen components in paddy soil derived from red earth].

    Science.gov (United States)

    Zong, Hai-ying; Wang, Kai-rong; Xie, Xiao-li

    2008-08-01

    A 16-year long-term fertilization experiment was conducted on paddy soil derived from red earth to investigate the effects of different fertilization patterns on the concentrations of soil organic nitrogen (N) components. When chemical fertilizers were applied only, the soil nitrogen content was slightly influenced. Organic fertilization, especially its combination with chemical fertilization, could significantly increase the contents of soil mineralizable N and organic nitrogen by 55.2% and 38.8%, respectively. In addition, organic fertilization could significantly improve the components of acid hydrolysable N, and lead to the increase of ammonium N (AN) , amino sugar N (ASN), and hydrolysable unidentified N (HUN) by 36.5%, 68.4%, and 73.9%, respectively. When the organic fertilization was combined with chemical fertilization, soil amino acid N content was increased by 71.1%, while HUN content was decreased by 34.5%. In all fertilization treatments, the cumulative amount of soil mineralized N increased with increasing incubation time. The content of soil mineralized N under organic fertilization and its combination with chemical fertilization was higher than that under chemical fertilization.

  15. Spatio-temporal variability of dissolved organic nitrogen (DON), carbon (DOC), and nutrients in the Nile River, Egypt.

    Science.gov (United States)

    Badr, El-Sayed A

    2016-10-01

    Increases in human activity have resulted in enhanced anthropogenic inputs of nitrogen (N) and carbon (C) into the Nile River. The Damietta Branch of the Nile is subject to inputs from industrial, agricultural, and domestic wastewater. This study investigated the distribution and seasonality of dissolved organic nitrogen (DON), dissolved organic carbon (DOC), and nutrients in the Nile Damietta Branch. Water samples were collected from 24 sites between May 2009 and February 2010. Dissolved organic nitrogen concentrations averaged 251 ± 115 μg/l, with a range of 90.2-671 μg/l, and contributed 40.8 ± 17.7 % to the total dissolved nitrogen (TDN) pool. Relative to autumn and winter, DON was a larger fraction of the TDN pool during spring and summer indicating the influence of bacterioplankton on the nitrogen cycle. Concentrations of DOC ranged from 2.23 to 11.3 mg/l with an average of 5.15 ± 2.36 mg/l, reflecting a high organic matter load from anthropogenic sources within the study area, and were highest during autumn. Higher values of biochemical oxygen demand (BOD), chemical oxygen demand (COD), DON, nitrate, and phosphate occurred downstream of the Damietta Branch and were probably due to anthropogenic inputs to the Nile from the Damietta district. A bacterial incubation experiment indicated that 52.1-95.0 % of DON was utilized by bacteria within 21 days. The decrease in DON concentration was accompanied by an increase in nitrate concentration of 54.8-87.3 %, presumably through DON mineralization. Based on these results, we recommend that water quality assessments consider DON and DOC, as their omission may result in an underestimation of the total organic matter load and impact.

  16. Simultaneous Analysis of Nitrogen, Carbon and Sulfur Stable Isotopes and Concentrations in Organics and Soils

    Science.gov (United States)

    Mambelli, S.; Brooks, P. D.; Sutka, R.; Hughes, S.; Finstad, K. M.; Pakes, M. J.; Dawson, T. E.

    2014-12-01

    To date, analysis of diet, food web complexities, biogeochemical cycles, and ecosystem functioning have largely focused on using variation in carbon (C) and nitrogen (N) stable isotope ratios. This is because a great deal is understood about what leads to this variation and because the dual stable isotope analysis of these two elements using continuous flow isotope ratio mass spectrometry (IRMS) is now commonplace. However, the aforementioned studies may all greatly benefit from the additional information one can get from also having sulfur (S) stable isotopes ratio data. Until very recently the analysis of δ34S has traditionally required an additional and often more difficult analytical procedure. Here, we report on the development of a new method that simultaneously analyzes the elemental and isotopic composition of N, C and S in a single sample. The new commercially available instrument includes a modified NCS elemental analyzer in line with an IRMS outfitted with 100 volt AD converters for wide dynamic range. We tested, and modified, this instrument to achieve maximum accuracy and precision for the isotopic measurements of all three elements. We found that the original design needed improvements to achieve our goals by: a) including a component (originally designed for trapping water) as buffer to reduce S memory and obtain reliable δ34S analysis; b) adding an external furnace for complete reduction of nitrogen oxides to N2 gas for accurate δ15N; c) adding a magnesium perchlorate water trap immediately after the reduction tube to minimize any water condensation that could also influence S memory. We analyzed a selection of organic materials and soils with approximately a 1:2 standards versus unknowns ratio per run. Using this NCS set-up, the precision of the N and C isotopic measurements was comparable to the one usually attained in NC mode alone (standard deviation of ± 0.13 δ15N in the range 30 to 400 µg N, and of ± 0.12 δ13C in the range 0.20 to 4 mg

  17. Acquired Methemoglobinaemia

    Directory of Open Access Journals (Sweden)

    Adil Al-Lawati

    2012-05-01

    Full Text Available Acquired methemoglobinaemia is a relatively rare condition and, therefore infrequently encountered in acute medical practice. Suspicion of the condition may be triggered when the measured PaO2 is ‘out of keeping’ with the oxygen saturations that are discovered with pulse oximetry. We describe two separate cases of acquired methemoglobinaemia secondary to the recreational use of alkyl nitrites (’poppers’. The patients presented at separate times to two different teaching hospitals in London, UK. The similarity of these cases has led the authors to conclude that a raised awareness of this potentially fatal condition, and its association with a widely-available recreational drug, is necessary to ensure a correct and timely diagnosis.

  18. Development and evaluation of a radial anaerobic/aerobic reactor treating organic matter and nitrogen in sewage

    Directory of Open Access Journals (Sweden)

    L. H. P. Garbossa

    2005-12-01

    Full Text Available The design and performance of a radial anaerobic/aerobic immobilized biomass (RAAIB reactor operating to remove organic matter, solids and nitrogen from sewage are discussed. The bench-scale RAAIB was divided into five concentric chambers. The second and fourth chambers were packed with polyurethane foam matrices. The performance of the reactor in removing organic matter and producing nitrified effluent was good, and its configuration favored the transfer of oxygen to the liquid mass due to its characteristics and the fixed polyurethane foam bed arrangement in concentric chambers. Partial denitrification of the liquid also took place in the RAAIB. The reactor achieved an organic matter removal efficiency of 84%, expressed as chemical oxygen demand (COD, and a total Kjeldahl nitrogen (TKN removal efficiency of 96%. Average COD, nitrite and nitrate values for the final effluent were 54 mg.L-1, 0.3 mg.L-1 and 22.1 mg.L-1, respectively.

  19. Evidence of reduced poly-B-hydroxybutyrate biosynthesis in free-living nitrogen-fixing bacteria, Azotobacter chroococcum, following acquired resistance to the fungicide captan.

    Science.gov (United States)

    Miclaus, N; Vannini, C; Celano, G; Piccolo, A; Simoncini, S

    1992-08-12

    Some biological activities of Azotobacter chroococcum, strain Azcap 1, (spontaneous mutant, captan resistant up to 300 micrograms/ml) were assayed on RM medium with and without the presence of the fungicide. Comparisons were also carried out with Az. chroococcum sensitive strains Azwt, Azcan 10 and 14. The hydrolysis of captan, incorporated in agar plates of RM at 100 micrograms/ml, was rapid, since on 4-day plates, no effect was found on the strain Azwt, while on freshly prepared ones its growth was completely blocked. As for Azcap 1, grown on RM only, the behaviour was similar to that of sensitive strains, whereas when grown on captan the results of experiments showed: (i) a lag of approximately 12 h to reach the maximum nitrogen-fixing activity; (ii) delay of 12-24 h in the full consumption of glucose present in the medium, although the invertase activity did not present differences; (iii) high ATP culture content during the 50 h of the experiment; (iv) approximately 6-10-fold lower production of PHB (poly-B-hydroxybutyrate); (v) lack of typical encystment phase, for the tested 96 h and reduced viability in developing colonies on agar RM medium. In contrast, when captan was added to cultural medium at sublethal concentration, 50 micrograms/ml for sensitive strain Azwt and 200 micrograms/ml for Azcap 1, the amount of glutathione produced (to remove the fungicide toxicity) was several times higher for the former.

  20. Formation of haloacetamides during chlorination of dissolved organic nitrogen aspartic acid

    Energy Technology Data Exchange (ETDEWEB)

    Chu Wenhai, E-mail: 1world1water@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Gao Naiyun [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092 (China); Deng Yang, E-mail: yang.deng@upr.edu [Department of Civil Engineering and Surveying, University of Puerto Rico, P.O. Box 9041, Mayaguez, Puerto Rico, 00681-9041 (Puerto Rico)

    2010-01-15

    The stability of haloacetamides (HAcAms) such as dichloroacetamide (DCAcAm) and trichloroacetamide (TCAcAm) was studied under different experimental conditions. The yield of HAcAms during aspartic acid (Asp) chlorination was measured at different molar ratio of chlorine atom to nitrogen atom (Cl/N), pH and dissolved organic carbon (DOC) mainly consisted of humic acid (HA) mixture. Ascorbic acid showed a better capacity to prevent the decay of DCAcAm and TCAcAm than the other two dechlorinating agents, thiosulfate and sodium sulfite. Lower Cl/N favored the DCAcAm formation, implying that breakpoint chlorination might minimize its generation. The pH decrease could lower the concentration of DCAcAm but favored dichloroacetonitrile (DCAN) formation. DCAcAm yield was sensitive to the DOC due to higher chlorine consumption caused by HA mixture. Two possible pathways of DCAcAm formation during Asp chlorination were proposed. Asp was an important precursor of DCAN, DCAcAm and dichloroacetic acid (DCAA), and thus removal of Asp before disinfection may be a method to prevent the formation of DCAcAm, DCAN and DCAA.

  1. Influence of Chlorsulfuron Contamination on Ratios of Biomass Carbon and Nitrogen to Total Organic Carbon and Nitrogen in Soil

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The extent and seriousness of the contamination of soils by pesticides still remain to be determined. In agricultural systems, herbicides are the largest class of pesticides used (Shea, 1985). Chlorsulfuron is one of the most important sulfonylurea herbicides with important feature of very high herbicidal activity, which results in extremely low application rates of 10~40 g ha-1 (Blair and Martin, 1988). The sulfonylurea herbicides can persist in the soil for more than 1 year (Brown, 1990). Therefore, there has been considerable interest in the side effects of these chemicals on non-target organisms, including soil microorganisms (Greaves and Malkomes, 1980). It is generally recognized that the microbial biomass is the eye of the needle through which all organic materials that enter the soil must pass (Jenkinson, 1988). Changes in the microbial biomass-C (Cmic) can provide an early indication of long-term trends in the total organic-C (Corg) of soils (Carter, 1986). The Cmic/Corg ratio has been found useful as an index of changes in soil organic matter resulting from land management changes (Hart et al., 1989). Many studies were done on relative effect of heavy metals on the ratio of Cmic/Corg but few studies have laid particular attention to the effect of herbicides on this ratio. The present paper reports on the Cmic/Corg and microbial biomass-N/total N (Nmic/Ntotal) ratios in soil as affected by chlorsulfuron.

  2. Soil Organic Carbon Response to Cover Crop and Nitrogen Fertilization under Bioenergy Sorghum

    Science.gov (United States)

    Sainju, U. M.; Singh, H. P.; Singh, B. P.

    2015-12-01

    Removal of aboveground biomass for bioenergy/feedstock in bioenergy cropping systems may reduce soil C storage. Cover crop and N fertilization may provide additional crop residue C and sustain soil C storage compared with no cover crop and N fertilization. We evaluated the effect of four winter cover crops (control or no cover crop, cereal rye, hairy vetch, and hairy vetch/cereal rye mixture) and two N fertilization rates (0 and 90 kg N ha-1) on soil organic C (SOC) at 0-5, 5-15, and 15-30 cm depths under forage and sweet sorghums from 2010 to 2013 in Fort Valley, GA. Cover crop biomass yield and C content were greater with vetch/rye mixture than vetch or rye alone and the control, regardless of sorghum species. Soil organic C was greater with vetch/rye than rye at 0-5 and 15-30 cm in 2011 and 2013 and greater with vetch than rye at 5-15 cm in 2011 under forage sorghum. Under sweet sorghum, SOC was greater with cover crops than the control at 0-5 cm, but greater with vetch and the control than vetch/rye at 15-30 cm. The SOC increased at the rates of 0.30 Mg C ha-1 yr-1 at 0-5 cm for rye and the control to 1.44 Mg C ha-1 yr-1 at 15-30 cm for vetch/rye and the control from 2010 to 2013 under forage sorghum. Under sweet sorghum, SOC also increased linearly at all depths from 2010 to 2013, regardless of cover crops. Nitrogen fertilization had little effect on SOC. Cover crops increased soil C storage compared with no cover crop due to greater crop residue C returned to the soil under forage and sweet sorghum and hairy vetch/cereal rye mixture had greater C storage than other cover crops under forage sorghum.

  3. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    Science.gov (United States)

    Bu, Rongyan; Lu, Jianwei; Ren, Tao; Liu, Bo; Li, Xiaokun; Cong, Rihuan

    2015-01-01

    Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N) mineralization. The quantity and quality of particulate organic matter (POM) and potentially mineralizable-N (PMN) contents were measured in soils from 16 paired rice-rapeseed (RR)/cotton-rapeseed (CR) rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile), intermediate (25th and 75th percentiles), and high (90th percentile) levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C) and N (POM-N) contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN) contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively) than CR rotations (45.6% and 19.5%, respectively). Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials) in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils.

  4. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    Directory of Open Access Journals (Sweden)

    Rongyan Bu

    Full Text Available Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N mineralization. The quantity and quality of particulate organic matter (POM and potentially mineralizable-N (PMN contents were measured in soils from 16 paired rice-rapeseed (RR/cotton-rapeseed (CR rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile, intermediate (25th and 75th percentiles, and high (90th percentile levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C and N (POM-N contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively than CR rotations (45.6% and 19.5%, respectively. Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils.

  5. Organic carbon and nitrogen export from a tropical dam-impacted floodplain system

    Directory of Open Access Journals (Sweden)

    R. Zurbrügg

    2012-06-01

    Full Text Available Tropical floodplains play an important role in organic matter transport, storage, and transformation between headwaters and oceans. However, the fluxes and quality of organic carbon (OC and organic nitrogen (ON in tropical river-floodplain systems are not well constrained. We explored the quantity and characteristics of dissolved and particulate organic matter (DOM and POM in the Kafue River flowing through the Kafue Flats (Zambia. The Kafue Flats are a tropical dam-impacted river-floodplain system in the Zambezi River basin. During the flooding season, >80% of the Kafue River water passed through the floodplain, mobilizing large quantities of OC and ON, which resulted in a net export of 75 kg OC km−2 d−1 and 2.9 kg ON km−2 d−1, 80% of which was in the dissolved form. Mass budget estimates showed that ON export, denitrification, and burial caused an annual deficit of ~21 000 t N yr−1 in the Kafue Flats. A N isotope balance and the δ15N of DON and PON suggest that N-fixation must level out the large N losses. The elemental C:N ratio of ~20, the δ13C values of higher than −24‰, and spectroscopic properties (excitation-emission matrices showed that DOM in the river was mainly of terrestrial origin. Despite a threefold increase in OC loads due to inputs from the floodplain, the river DOM characteristics remained relatively constant along the sampled 400-km river reach. This suggested that floodplain DOM had similar properties than DOM from the upstream reservoir. In contrast, based on its low δ13C of −29‰ and the C:N ratio of ~8, POM originated from phytoplankton production in the upstream reservoir and in the floodplain. While the reservoir had little impact on DOM properties, terrestrial POM was efficiently trapped and, instead, phytoplankton-derived POM was discharged to the downstream Kafue Flats.

  6. Metal-Organic Framework Derived Hierarchically Porous Nitrogen-Doped Carbon Nanostructures as Novel Electrocatalyst for Oxygen Reduction Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Shaofang; Zhu, Chengzhou; Zhou, Yazhou; Yang, Guohai; Jeon, Ju Won; Lemmon, John P.; Du, Dan; Nune, Satish K.; Lin, Yuehe

    2015-10-01

    The hierarchically porous nitrogen-doped carbon materials, derived from nitrogen-containing isoreticular metal-organic framework-3 (IRMOF-3) through direct carbonization, exhibited excellent electrocatalytic activity in alkaline solution for oxygen reduction reaction (ORR). This high activity is attributed to the 10 presence of high percentage of quaternary and pyridinic nitrogen, the high surface area as well as good conductivity. When IRMOF-3 was carbonized at 950 °C (CIRMOF-3-950), it showed four-electron reduction pathway for ORR and exhibited better stability (about 78.5% current density was maintained) than platinum/carbon (Pt/C) in the current durability test. In addition, CIRMOF-3-950 presented high selectivity to cathode reactions compared to commercial Pt/C.

  7. Dynamics of exogenous nitrogen partitioning and nitrogen remobilization from vegetative organs in pea revealed by 15N in vivo labeling throughout seed filling.

    Science.gov (United States)

    Schiltz, Séverine; Munier-Jolain, Nathalie; Jeudy, Christian; Burstin, Judith; Salon, Christophe

    2005-04-01

    The fluxes of (1) exogenous nitrogen (N) assimilation and (2) remobilization of endogenous N from vegetative plant compartments were measured by 15N labeling during the seed-filling period in pea (Pisum sativum L. cv Cameor), to better understand the mechanism of N remobilization. While the majority (86%) of exogenous N was allocated to the vegetative organs before the beginning of seed filling, this fraction decreased to 45% at the onset of seed filling, the remainder being directed to seeds. Nitrogen remobilization from vegetative parts contributed to 71% of the total N in mature seeds borne on the first two nodes (first stratum). The contribution of remobilized N to total seed N varied, with the highest proportion at the beginning of filling; it was independent of the developmental stage of each stratum of seeds, suggesting that remobilized N forms a unique pool, managed at the whole-plant level and supplied to all filling seeds whatever their position on the plant. Once seed filling starts, N is remobilized from all vegetative organs: 30% of the total N accumulated in seeds was remobilized from leaves, 20% from pod walls, 11% from roots, and 10% from stems. The rate of N remobilization was maximal when seeds of all the different strata were filling, consistent with regulation according to the N demand of seeds. At later stages of seed filling, the rate of remobilization decreases and may become controlled by the amount of residual N in vegetative tissues.

  8. [Effects of nitrogen application on soil greenhouse gas fluxes in Eucalyptus plantations with different soil organic carbon content].

    Science.gov (United States)

    Li, Rui-Da; Zhang, Kai; Su, Dan; Lu, Fei; Wan, Wu-Xing; Wang, Xiao-Ke; Zheng, Hua

    2014-10-01

    The effects of nitrogen fertilization or nitrogen deposition on soil greenhouse gases fluxes has been well studied, while little has been piloted about the effects of nitrogen application on soil greenhouse gas fluxes and its discrepancy with different soil organic carbon content. In our study, we conducted field control experiment in a young Eucalyptus plantation in Southeast China. We compared the effects of 4 levels of nitrogen fertilization (Control: 0 kg · hm(-2); Low N: 84.2 kg · hm(-2); Medium N: 166.8 kg · hm(-2); High N: 333.7 kg · hm(-2)) on soil GHGs fluxes from 2 sites (LC and HC) with significantly different soil organic carbon (SOC) content (P Fertilization had significant priming effect on CO2 and N2O emission fluxes. One month after fertilization, both CO2 and N2O had the flux peak and decreased gradually, and the difference among the treatments disappeared at the end of the growing season. However, fertilization had no significant effect on CH4 oxidation between the 2 sites. (2) Fertilization and SOC were two crucial factors that had significant effects on CO2 and N2O emission. Fertilization had a significant positive effect on CO2 and N2O emission fluxes (P 0.05). The CO2 and N2O emission fluxes were significantly higher in HC than those in LC (P Fertilization and SOC had great interactive effect on CO2 and N2O emission (P fertilization on soil GHGs fluxes were not only in connection with the intensify of nitrogen, but also closely tied to the SOC content. When we assess the effects of nitrogen on soil GHGs fluxes, the difference induced by SOC should not be ignored.

  9. Soil organic carbon and total nitrogen gains in an old growth deciduous forest in Germany.

    Directory of Open Access Journals (Sweden)

    Marion Schrumpf

    Full Text Available Temperate forests are assumed to be organic carbon (OC sinks, either because of biomass increases upon elevated CO2 in the atmosphere and large nitrogen deposition, or due to their age structure. Respective changes in soil OC and total nitrogen (TN storage have rarely been proven. We analysed OC, TN, and bulk densities of 100 soil cores sampled along a regular grid in an old-growth deciduous forest at the Hainich National Park, Germany, in 2004 and again in 2009. Concentrations of OC and TN increased significantly from 2004 to 2009, mostly in the upper 0-20 cm of the mineral soil. Changes in the fine earth masses per soil volume impeded the detection of OC changes based on fixed soil volumes. When calculated on average fine earth masses, OC stocks increased by 323 ± 146 g m(-2 and TN stocks by 39 ± 10 g m(-2 at 0-20 cm soil depth from 2004 to 2009, giving average annual accumulation rates of 65 ± 29 g OC m(-2 yr(-1 and 7.8 ± 2 g N m(-2 yr(-1. Accumulation rates were largest in the upper part of the B horizon. Regional increases in forest biomass, either due to recovery of forest biomass from previous forest management or to fertilization by elevated CO2 and N deposition, are likely causes for the gains in soil OC and TN. As TN increased stronger (1.3% yr(-1 of existing stocks than OC (0.9% yr(-1, the OC-to-TN ratios declined significantly. Results of regression analyses between changes in OC and TN stocks suggest that at no change in OC, still 3.8 g TN m(-2 yr(-1 accumulated. Potential causes for the increase in TN in excess to OC are fixation of inorganic N by the clay-rich soil or changes in microbial communities. The increase in soil OC corresponded on average to 6-13% of the estimated increase in net biome productivity.

  10. Soil organic carbon and total nitrogen gains in an old growth deciduous forest in Germany.

    Science.gov (United States)

    Schrumpf, Marion; Kaiser, Klaus; Schulze, Ernst-Detlef

    2014-01-01

    Temperate forests are assumed to be organic carbon (OC) sinks, either because of biomass increases upon elevated CO2 in the atmosphere and large nitrogen deposition, or due to their age structure. Respective changes in soil OC and total nitrogen (TN) storage have rarely been proven. We analysed OC, TN, and bulk densities of 100 soil cores sampled along a regular grid in an old-growth deciduous forest at the Hainich National Park, Germany, in 2004 and again in 2009. Concentrations of OC and TN increased significantly from 2004 to 2009, mostly in the upper 0-20 cm of the mineral soil. Changes in the fine earth masses per soil volume impeded the detection of OC changes based on fixed soil volumes. When calculated on average fine earth masses, OC stocks increased by 323 ± 146 g m(-2) and TN stocks by 39 ± 10 g m(-2) at 0-20 cm soil depth from 2004 to 2009, giving average annual accumulation rates of 65 ± 29 g OC m(-2) yr(-1) and 7.8 ± 2 g N m(-2) yr(-1). Accumulation rates were largest in the upper part of the B horizon. Regional increases in forest biomass, either due to recovery of forest biomass from previous forest management or to fertilization by elevated CO2 and N deposition, are likely causes for the gains in soil OC and TN. As TN increased stronger (1.3% yr(-1) of existing stocks) than OC (0.9% yr(-1)), the OC-to-TN ratios declined significantly. Results of regression analyses between changes in OC and TN stocks suggest that at no change in OC, still 3.8 g TN m(-2) yr(-1) accumulated. Potential causes for the increase in TN in excess to OC are fixation of inorganic N by the clay-rich soil or changes in microbial communities. The increase in soil OC corresponded on average to 6-13% of the estimated increase in net biome productivity.

  11. Global modeling study of soluble organic nitrogen from open biomass burning

    Science.gov (United States)

    Ito, Akinori; Lin, Guangxing; Penner, Joyce E.

    2015-11-01

    Atmospheric deposition of reactive nitrogen (N) species from large fires may contribute to enrichment of nutrients in aquatic ecosystems. Here we use an atmospheric chemistry transport model to investigate the supply of soluble organic nitrogen (ON) from open biomass burning to the ocean. The model results show that the annual deposition rate of soluble ON to the oceans (14 Tg N yr-1) is increased globally by 13% with the increase being particularly notable over the tropical oceans downwind from the source regions. The estimated deposition of soluble ON due to biomass burning from the secondary formation (1.0 Tg N yr-1) is close to that from the primary sources (1.2 Tg N yr-1). We examine the secondary formation of particulate C-N compounds (i.e., imidazole, methyl imidazole, and N-containing oligomers) from the reactions of glyoxal (CHOCHO) and methylglyoxal (CH3COCHO) with ammonium (NH4+) in wet aerosols and upon cloud evaporation. These ON sources result in a significant contribution to the open ocean (1.3 Tg N yr-1), suggesting that atmospheric processing in aqueous-phase may have a large effect. We compare the soluble ON concentration in aerosols with and without open biomass burning as a case study in Singapore. The model results demonstrate that the soluble ON concentration in aerosols is episodically enriched during the fire events, compared to the case without smoke simulations. At the same time, the model results show that the daily soluble ON concentration can be also enhanced in the case without smoke simulations, compared to the monthly averages. These results may suggest that both the primary source strength of ON and the secondary formation rates of ON should be taken into consideration when using in-situ observations to constrain the calculated soluble ON burden due to biomass burning. More accurate quantification of the soluble ON burdens both with and without smoke sources is therefore needed to assess the effect of biomass burning on bioavailable

  12. Effects of topographical position on soil organic carbon and nitrogen in Mediterranean olive groves

    Science.gov (United States)

    Lozano-García, Beatriz; Parras-Alcántara, Luis

    2014-05-01

    INTRODUCTION The most important and extensive crops in the Mediterranean area are olive groves. Within the last 50 years, the surface occupied by olive groves has progressively increased in Spain including more complex topographies, with steeper slopes and higher altitudes. This situation has caused serious erosion problems; there is a huge range of studies assessing possible solutions to this problem and new tillage and management techniques have been developed (Lozano-García and Parras-Alcántara, 2013). However, topography has influence in soil properties too. The impact of the topographical position on soil properties, including soil organic carbon (SOC) and Nitrogen (N) stocks, and soil quality (expressed as Stratification Ratios-SRs) was evaluated in a Mediterranean olive grove with traditional tillage. MATERIAL AND METHODS The study was carried out in a rain-fed olive grove in Jaén managed with traditional tillage (with disc harrow 25 cm) and receiving mineral fertilization. Three topographical positions with the same aspect: summit, backslope and toeslope were chosen for evaluation. The soil samples were taken from four soil sections of 0.25 m (0-1 m) in order to establish a good comparison. Soil properties determined were: soil particle size, SOC and total Nitrogen (N). SOC and N stock, expressed for a specific depth in Mg ha-1. Stratification ratios (that can be used as an indicator of dynamic soil quality) for SOC and N at three different depths were calculated. The effect of topographical position on SOC and N stocks and other soil properties was analyzed using a ANOVA, followed by a Tuckey test. RESULTS SOC decreased with depth, in addition, the SOC and N content increased along the downslope direction (5.5, 6.5 and 7.1 g C kg-1; and 0.3, 0.8 and 0.9 g N kg-1 in the surface layer in the summit, backslope and toeslope respectively) as well as SOC stock considering the two first soil sections. The N stock varied significantly along the topographical

  13. CHANGING BACTERIAL ORGANISMS AND ANTIMICROBIAL RESISTANCE PATTERN AMONG HOSPITALIZED COMMUNITY ACQUIRED PNEUMONIA PATIENTS IN A TERTIARY CARE CENTER

    Directory of Open Access Journals (Sweden)

    Raveendra Kodur

    2013-04-01

    Full Text Available ABSTRACT: BACKGROUND: Most of the times a Community Acquired Pneumonia (CAP patient is being treated with empirical antibiotics by best guess method by the clinician.MDR strains are being reported from c/s reports and Gram negative rods are fast increasing both in the etiolog y and mortality of CAP patients AIM OF STUDY: 1. To find out the profile of different bacteria causing CAP at a tertiary hospital. 2. To know the treatment outcome & drug resistance pattern among culture positive CAP patients. MATERIALS & METHODS: 450 CAP patients admitted & treated between Jan. to Dec.2012 at Victoria Hospital, Bangalore were included in this hospitalized cross sectional study. All relevant investigations including sputum c/s were done. RESULTS: Positive culture reports were obtained in 165(36.33% out of 450 patients Following are the isolates - Strept.pnemoniae 32.7%, Klebsiella 18.2%, Staph.aureas 10.9%, Psedomonas 10.9%, E.coli 5.4%, Acinetobacter 7.3%, H.influenza 5.4%, Mixed growth 10%. 76% of patients recovered from CAP, 6% went a gainst medical advice, 6.6% showed unresolved pneumonia & deaths in 5.33% of patients. High degree of resistance was noted to many antibiotics including to latest cephalosporins. CONCLUSION: This study highlights the importance of culture tests and selection of proper antibiotics and to avoid misuse & abuse of higher antibiotics to prevent the emergence of MDR strains. An antibiotic policy at every level may help.

  14. Acquired Techniques

    DEFF Research Database (Denmark)

    Lunde Nielsen, Espen; Halse, Karianne

    2013-01-01

    Acquired Techniques - a Leap into the Archive, at Aarhus School of Architecture. In collaboration with Karianne Halse, James Martin and Mika K. Friis. Following the footsteps of past travelers this is a journey into tools and techniques of the architectural process. The workshop will focus upon...... architectural production as a conglomerate of various analogue and digital methods, and provide the basics, the tips/tricks - and how the tool themselves becomes operational for spatial/thematic investigations. Eventually, this will become a city, exhibition and phamplet inhabited by the (by...

  15. Resolving the 'nitrogen paradox' of arbuscular mycorrhizas: fertilization with organic matter brings considerable benefits for plant nutrition and growth.

    Science.gov (United States)

    Thirkell, Tom J; Cameron, Duncan D; Hodge, Angela

    2016-08-01

    Arbuscular mycorrhizal fungi (AMF) can transfer nitrogen (N) to host plants, but the ecological relevance is debated, as total plant N and biomass do not generally increase. The extent to which the symbiosis is mutually beneficial is thought to rely on the stoichiometry of N, phosphorus (P) and carbon (C) availability. While inorganic N fertilization has been shown to elicit strong mutualism, characterized by improved plant and fungal growth and mineral nutrition, similar responses following organic N addition are lacking. Using a compartmented microcosm experiment, we determined the significance to a mycorrhizal plant of placing a (15) N-labelled, nitrogen-rich patch of organic matter in a compartment to which only AMF hyphae had access. Control microcosms denied AMF hyphal access to the patch compartment. When permitted access to the patch compartment, the fungus proliferated extensively in the patch and transferred substantial quantities of N to the plant. Moreover, our data demonstrate that allowing hyphal access to an organic matter patch enhanced total plant N and P contents, with a simultaneous and substantial increase in plant biomass. Furthermore, we demonstrate that organic matter fertilization of arbuscular mycorrhizal plants can foster a mutually beneficial symbiosis based on nitrogen transfer, a phenomenon previously thought irrelevant.

  16. Reduction of nitrogen compounds in oceanic basement and its implications for HCN formation and abiotic organic synthesis

    Directory of Open Access Journals (Sweden)

    Neubeck Anna

    2009-10-01

    Full Text Available Abstract Hydrogen cyanide is an excellent organic reagent and is central to most of the reaction pathways leading to abiotic formation of simple organic compounds containing nitrogen, such as amino acids, purines and pyrimidines. Reduced carbon and nitrogen precursor compounds for the synthesis of HCN may be formed under off-axis hydrothermal conditions in oceanic lithosphere in the presence of native Fe and Ni and are adsorbed on authigenic layer silicates and zeolites. The native metals as well as the molecular hydrogen reducing CO2 to CO/CH4 and NO3-/NO2- to NH3/NH4+ are a result of serpentinization of mafic rocks. Oceanic plates are conveyor belts of reduced carbon and nitrogen compounds from the off-axis hydrothermal environments to the subduction zones, where compaction, dehydration, desiccation and diagenetic reactions affect the organic precursors. CO/CH4 and NH3/NH4+ in fluids distilled out of layer silicates and zeolites in the subducting plate at an early stage of subduction will react upon heating and form HCN, which is then available for further organic reactions to, for instance, carbohydrates, nucleosides or even nucleotides, under alkaline conditions in hydrated mantle rocks of the overriding plate. Convergent margins in the initial phase of subduction must, therefore, be considered the most potent sites for prebiotic reactions on Earth. This means that origin of life processes are, perhaps, only possible on planets where some kind of plate tectonics occur.

  17. Organics and nitrogen removal from textile auxiliaries wastewater with A2O-MBR in a pilot-scale.

    Science.gov (United States)

    Sun, Faqian; Sun, Bin; Hu, Jian; He, Yangyang; Wu, Weixiang

    2015-04-01

    The removal of organic compounds and nitrogen in an anaerobic-anoxic-aerobic membrane bioreactor process (A(2)O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH4(+)-N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH4(+)-N and TN were 87%, 96% and 55%, respectively. Gas chromatograph-mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry.

  18. Nitrogen Mineralization of a Loam Soil Supplemented with Organic-Inorganic Amendments under Laboratory Incubation.

    Science.gov (United States)

    Abbasi, M Kaleem; Khaliq, Abdul

    2016-01-01

    The quantification of nitrogen (N) supplying capacity of organic amendments applied to a soil is of immense importance to examine synchronization, N release capacity, and fertilizer values of these added materials. The aims of the present study was to determine the potential N mineralization and subsequent nitrification of separate and combined use of poultry manure (PM), wheat straw residues (WSR), and urea N (UN) applied to a loam soil incubated periodically over 140 days period. In addition, changes in total soil N and carbon contents were also monitored during the study. Treatments included: PM100, WSR100, PM50 + WSR50, UN100, UN50 + PM50, UN50 + WSR50, UN50 + PM25 + WSR25, and a control (unfertilized). All the amendments were applied on an N-equivalent basis at the rate of 200 mg N kg(-1). Results indicated that a substantial quantity of N had been released from the added amendments into the soil mineral pool and the net cumulative N mineralized varied between 39 and 147 mg N kg(-1), lowest in the WSR and highest in the UN50 + PM50. Significant differences were observed among the amendments and the net mineral N derived from a separate and combined use of PM was greater than the other treatments. The net cumulative N nitrified (NCNN) varied between 16 and 126 mg kg(-1), highest in UN50 + PM50 treatment. On average, percentage conversion of added N into available N by different amendments varied between 21 and 80%, while conversion of applied N into NO3 (-)-N ranged between 9 and 65%, and the treatment UN50 + PM50 displayed the highest N recovery. Urea N when applied alone showed disappearance of 37% N (N unaccounted for) at the end while application of PM and WSR with UN reduced N disappearance and increased N retention in the mineral pool for a longer period. Organic amendments alone or in combination with UN improved organic matter buildup and increased soil N concentration. These results demonstrate the existence of substantial amounts of N reserves present

  19. Resolving the influence of nitrogen abundances on sediment organic matter in macrophyte-dominated lakes, using fluorescence spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Xin Yao; Shengrui Wang; Lixin Jiao; Caihong Yan; Xiangcan Jin

    2015-01-01

    A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis.Macrophyte biomass showed coincident growth trends with time,but different variation rates with nitrogen treatment.All plant growth indexes with nitrogen addition (N,NH4Cl 100,200,400 mg/kg,respectively) were lower than those of the control group.Four humiclike components,two autochthonous tryptophan-like components,and one autochthonous tyrosine-like component were identified using the parallel factor analysis model.The results suggested that the relative component changes of fluorescence in the colonized sediments were in direct relation to the change of root biomass with time.In the experiment,the root formation parameters of the plants studied were significantly affected by adding N in sediments,which may be related to the reason that the root growth was affected by N addition.Adding a low concentration of N to sediments can play a part in supplying nutrients to the plants.However,the intensive uptake of NH~ may result in an increase in the intracellular concentration of ammonia,which is highly toxic to the plant cells.Hence,our experiment results manifested that organic matter cycling in the macrophyte-dominated sediment was influenced by nitrogen enrichment through influencing vegetation and relevant microbial activity.

  20. Overcoming organic and nitrogen overload in thermophilic anaerobic digestion of pig slurry by coupling a microbial electrolysis cell.

    Science.gov (United States)

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-09-01

    The combination of the anaerobic digestion (AD) process with a microbial electrolysis cell (MEC) coupled to an ammonia stripping unit as a post-treatment was assessed both in series operation, to improve the quality of the effluent, and in loop configuration recirculating the effluent, to increase the AD robustness. The MEC allowed maintaining the chemical oxygen demand removal of the whole system of 46±5% despite the AD destabilization after doubling the organic and nitrogen loads, while recovering 40±3% of ammonia. The AD-MEC system, in loop configuration, helped to recover the AD (55% increase in methane productivity) and attained a more stable and robust operation. The microbial population assessment revealed an enhancement of AD methanogenic archaea numbers and a shift in eubacterial population. The AD-MEC combined system is a promising strategy for stabilizing AD against organic and nitrogen overloads, while improving the quality of the effluent and recovering nutrients for their reutilization.

  1. Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond-constructed wetland systems.

    Science.gov (United States)

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Sen; Wu, Qing; Yan, Lijian

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

  2. Performance of organics and nitrogen removal in subsurface wastewater infiltration systems by intermittent aeration and shunt distributing wastewater.

    Science.gov (United States)

    Pan, Jing; Yuan, Fang; Yu, Long; Huang, Linli; Fei, Hexin; Cheng, Fan; Zhang, Qi

    2016-07-01

    Organics and nitrogen removal in four subsurface wastewater infiltration systems (SWISs), named SWIS A (without intermittent aeration and shunt distributing wastewater), SWIS B (with intermittent aeration), SWIS C (with shunt distributing wastewater) and SWIS D (with intermittent aeration and shunt distributing wastewater) was investigated. High average removal rates of 92.3% for COD, 90.2% for NH4-N and 88.1% for TN were achieved simultaneously in SWIS D compared with SWIS A, B and C. The excellent TN removal of SWIS D was due to intermittent aeration provided sufficient oxygen for nitrification in upper matrix and the favorable anoxic or anaerobic environment for denitrification in subsequent matrix, and moreover, shunt distributing wastewater provided sufficient carbon source for denitrification process. The results indicated that intermittent artificial aeration combined with shunt distributing wastewater could achieve high organics and nitrogen removal in SWISs.

  3. Amounts of substrate carbon and nitrogen control the decomposition of soil organic matter

    Science.gov (United States)

    Liu, X. J. A.; Sun, J.; Finley, B. K.; Dijkstra, P.; Schwartz, E.; Hungate, B. A.

    2015-12-01

    Climate change, mainly caused by rising atmospheric CO2 and nitrogen (N) deposition due to human activities, is postulated to increase energy and nutrient inputs to soils that can accelerate or retard soil organic matter (SOM) decomposition, a phenomenon called the priming effect. Yet, the direction and magnitude of priming in response to different amounts of energy and nutrient inputs remain elusive. Here we examined the effects of carbon (C) and N additions on priming, microbial turnover, extracellular enzyme activities, CO2 fluxes, and C accumulation in four different ecosystems. We applied low and high C (13C glucose; 350 and 1000 μg C g-1 wk-1) and C with N (NH4NO3; 35 and 100 μg N g-1 wk-1) for five weeks. We found: 1) high C and high C+N stimulated weekly priming in the first two weeks and then leveled off, indicating soil microorganisms may have a short-term of accelerated growth and activity but quickly adapt to frequent inputs of high substrate amounts, 2) high C induced greater cumulative priming, microbial turnover, and β-glucosidase activities than low C, 3) high C+N had significantly lower cumulative priming, turnover, and β-glucosidase activities than high C, 4) high C and high C+N stimulated greater CO2 fluxes and C accumulations than low substrate inputs. These results suggest that the amount of substrate (energy and nutrient) was a determinant factor in modulating the rate of SOM decomposition, microbial turnover, enzyme activities, and C balance. Overall we demonstrate that increased energy inputs can quickly accelerate SOM decomposition, but concurrent nutrient inputs can suppress such process, which could have a huge impact on terrestrial C storage and global biogeochemical C cycling under climate change.

  4. Organic Nitrogen Concentrations and Trends in Urban Stormwater: Implications for Stormwater Monitoring and Management

    Science.gov (United States)

    Lusk, M. G.; Toor, G.

    2014-12-01

    Organic nitrogen (ON) can be a significant contributor of bioavailable N to the phytoplankton and bacteria that cause eutrophication and harmful algal blooms. In urban systems, urban stormwater runoff containing ON compounds is one source of potentially bioavailable N in water bodies. However, ON characterization and concentrations in urban stormwater are rarely reported or considered for urban stormwater management. We instrumented a 13-hectare residential catchment in Florida's Tampa Bay area with an ISCO autosampler and collected storm event runoff samples at 15-minute intervals during the 2013 wet season (June to September, n =236). Our objectives were to determine the (1) relative importance of ON compared to inorganic N forms (i.e., NO3- and NH4+) in the runoff, (2) investigate temporal trends in the ON concentrations in runoff, and (3) assess how rainfall depth and intensity affect any temporal trends. Mean concentration of total N in stormwater runoff for the wet season was 1.86 mg/l, of which dissolved and particulate ON were 63%. The dominance of ON in urban stormwater runoff suggests that the ON fraction should also be targeted when stormwater control measures call for N reductions. Particulate ON (PON) displayed a strong seasonal first flush trend as season progressed from June (1.45 mg/l; n =75) to September (0.20 mg/l; n = 28), while dissolved ON (DON) did not display any seasonal trend, with mean monthly concentrations ranging from 0.36 to 0.80 mg/l. A principal component analysis using storm event N concentrations, rainfall depth, and rainfall intensity as variables showed no significant correlation, suggesting that storms of various sizes and intensities can mobilize ON. The seasonal first flush observed for PON in the wet season can provide a window of time for optimal N removal and implies that stormwater best management practices should focus on capturing plant materials earlier in the season.

  5. Changes in microbial community characteristics and soil organic matter with nitrogen additions in two tropical forests.

    Science.gov (United States)

    Cusack, Daniela F; Silver, Whendee L; Torn, Margaret S; Burton, Sarah D; Firestone, Mary K

    2011-03-01

    Microbial communities and their associated enzyme activities affect the amount and chemical quality of carbon (C) in soils. Increasing nitrogen (N) deposition, particularly in N-rich tropical forests, is likely to change the composition and behavior of microbial communities and feed back on ecosystem structure and function. This study presents a novel assessment of mechanistic links between microbial responses to N deposition and shifts in soil organic matter (SOM) quality and quantity. We used phospholipid fatty acid (PLFA) analysis and microbial enzyme assays in soils to assess microbial community responses to long-term N additions in two distinct tropical rain forests. We used soil density fractionation and 13C nuclear magnetic resonance (NMR) spectroscopy to measure related changes in SOM pool sizes and chemical quality. Microbial biomass increased in response to N fertilization in both tropical forests and corresponded to declines in pools of low-density SOM. The chemical quality of this soil C pool reflected ecosystem-specific changes in microbial community composition. In the lower-elevation forest, there was an increase in gram-negative bacteria PLFA biomass, and there were significant losses of labile C chemical groups (O-alkyls). In contrast, the upper-elevation tropical forest had an increase in fungal PLFAs with N additions and declines in C groups associated with increased soil C storage (alkyls). The dynamics of microbial enzymatic activities with N addition provided a functional link between changes in microbial community structure and SOM chemistry. Ecosystem-specific changes in microbial community composition are likely to have far-reaching effects on soil carbon storage and cycling. This study indicates that microbial communities in N-rich tropical forests can be sensitive to added N, but we can expect significant variability in how ecosystem structure and function respond to N deposition among tropical forest types.

  6. Organic and nitrogen fertilization of soil under Syrah grapevine: effects on soil chemical properties and nitrate concentration.

    OpenAIRE

    Davi José Silva; Luís Henrique Bassoi; Marlon Gomes da Rocha; Alexsandro Oliveira da Silva; Magnus Dall’Igna Deon

    2016-01-01

    ABSTRACT Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments cons...

  7. Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration

    OpenAIRE

    Silva,Davi José; Bassoi,Luís Henrique; Rocha,Marlon Gomes da; Silva, Alexsandro Oliveira da [UNESP; Deon,Magnus Dall'Igna

    2016-01-01

    ABSTRACT Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments cons...

  8. Functional differences in the allometry of the water, carbon and nitrogen content of gelatinous organisms

    KAUST Repository

    Molina-Ramírez, Axayacatl

    2015-05-19

    We have supplemented available, concurrent measurements of fresh weight (W, g) and body carbon (C, g) (46 individuals, 14 species) and nitrogen (N, g) (11 individuals, 9 species) of marine gelatinous animals with data obtained during the global ocean MALASPINA 2010 Expedition (totalling 267 individuals and 33 species for the W versus C data; totalling 232 individuals and 31 species for the N versus C data). We then used those data to test the allometric properties of the W versus C and N versus C relationships. Overall, gelatinous organisms contain 1.13 ± 1.57% of C (by weight, mean ± SD) in their bodies and show a C:N of 4.56 ± 2.46, respectively, although estimations can be improved by using separate conversion coefficients for the carnivores and the filter feeders. Reduced major axis regression indicates that W increases isometrically with C in the carnivores (cnidarians and ctenophores), implying that their water content can be described by a single conversion coefficient of 173.78 gW(g C)-1, or a C content of 1.17 ± 1.90% by weight, although there is much variability due to the existence of carbon-dense species. In contrast, W increases more rapidly than C in the filter feeders (salps and doliolids), according to a power relationship W = 446.68C1.54. This exponent is not significantly different from 1.2, which is consistent with the idea that the watery bodies of gelatinous animals represent an evolutionary response towards increasing food capture surfaces, i.e. a bottom-up rather than a top-down mechanism. Thus, the available evidence negates a bottom-up mechanism in the carnivores, but supports it in the filter feeders. Last, N increases isometrically with C in both carnivores and filter feeders with C:N ratios of 3.89 ± 1.34 and 4.38 ± 1.21, respectively. These values are similar to those of compact, non-gelatinous organisms and reflect a predominantly herbivorous diet in the filter feeders, which is confirmed by a difference of one trophic level

  9. Efficient nitrogen recycling through sustainable use of organic wastes in agriculture - an Australian case study

    Science.gov (United States)

    Rigby, Hannah; Landman, Michael; Collins, David; Walton, Katrina; Penney, Nancy; Pritchard, Deborah

    2014-05-01

    The effective recycling of nutrients in treated sewage sludge (biosolids) domestic (e.g. source separated food waste), agricultural, and commercial and industrial (C&I) biowastes (e.g. food industry wastes, papermill sludge) for use on land, generally following treatment (e.g. composting, anaerobic digestion or thermal conversion technologies) as alternatives to conventional mineral fertilisers in Australia can have economic benefits, ensure food security, and close the nutrient loop. In excess of 75% of Australian agricultural soils have less than 1% organic matter (OM), and, with 40 million tonnes of solid waste per year potentially available as a source of OM, biowastes also build soil carbon (C) stocks that improve soil structure, fertility and productivity, and enhance soil ecosystem services. In recent years, the increasing cost of conventional mineral fertilisers, combined with changing weather patterns have placed additional pressure on regional and rural communities. Nitrogen (N) is generally the most limiting nutrient to crop production, and the high-energy required and GHGs associated with its manufacture mean that, additionally, it is critical to use N efficiently and recycle N resources where possible. Biosolids and biowastes have highly variable organic matter (OM) and nutrient contents, with N often present in a variety of forms only some of which are plant-available. The N value is further influenced by treatment process, storage and fundamental soil processes. The correct management of N in biowastes is essential to reduce environmental losses through leaching or runoff and negative impacts on drinking water sources and aquatic ecosystems. Gaseous N emissions also impact upon atmospheric quality and climate change. Despite the body of work to investigate N supply from biosolids, recent findings indicate that historic and current management of agricultural applications of N from biosolids and biowastes in Australia may still be inefficient leading

  10. [Pathology of the internal organs and central nervous system in acquired immunodeficiency syndrome (with special reference to opportunistic infections)].

    Science.gov (United States)

    Masini, T; Chinaglia, D; Riviera, L; Capricci, E; Gullotta, F; Spigolon, G; Bauer, A L

    1990-01-01

    Extracerebral and cerebral pathology in AIDS (with particular emphasis on the opportunistic infections). The Authors present the extracerebral pathology of 27 cases of AIDS observed at the Department of Pathology of Milan and the cerebral pathology of 80 cases of AIDS collected by three Institutes (Department of Pathology of Milan, Department of Pathology of Rimini and Department of Neuropathology of Münster) with particular emphasis on the pathology of the opportunistic infections. In the adults' group, the most frequent infections are the protozoan ones (T. gondii) followed with equal incidence by the viral and fungal diseases. In the pediatric group the viral diseases are the most frequently seen. Almost all of the adults show multiple infections in the same organ or in different organs. Diffuse lesions with heavy pathologic fields were observed also without tissue reaction. As to cerebral pathology AIDS' patients with opportunistic infections show focal symptoms, whereas the so called "subacute microglial encephalitis" generally appears as a demential syndrome. In cases with progressive multifocal leukoencephalopathy JC virus was always found and in one case also SV 40 - and BK virus. The diffuse demyelinization in some cases of HIV-Encephalopathy is aspecific. In HIV-positive newborns with cerebral signs, the lesions are characterized by oedema, spongiosis and microcalcifications of the basal ganglia; these are aspecific lesions which can be found in toxic and infectious encephalopathies.

  11. Water Soluble Organic Nitrogen in atmospheric aerosol samples from urban, sub-urban and pristine areas of Venezuela

    Science.gov (United States)

    Canelon, R.; Giuliante, A.; Aguiar, G.; Ghneim, T.; Perez, T.

    2007-12-01

    Concentrations of water soluble organic nitrogen (WSON) were determined in atmospheric total suspended particles (TSP) collected between September of 2005 and May of 2006, in an urban continental (Caracas, 10° 29' 09'' N, 66° 53' 48'' W), an urban coastal (Catia la mar, 10° 35' 47'' N, 67° 01' 45'' W), a sub-urban coastal (Osma, 10° 32' N, 67° 28' W), a suburban continental (Altos de Pipe, 10° 23' 41'' N, 63° 59' 10'' W), a pristine coastal (Isla de Aves, 15° 40' N, 63° 36' W) and a pristine continental (La Gran Sabana National Park, 5° 41' 30'' N, 61° 34' 20'' W) areas of Venezuela. TSP samples were collected using a Hi-Vol airborne particle sampler. TSP were impacted on a fiberglass filter pretreated under 400° C for 4 hours to minimize organic nitrogen contamination. Ultra sound water extractions of the sample filters were performed and their NH4+, NO2- and NO3- concentrations were determined by ion exchange liquid chromatography. The water extracts were UV digested and the nitrogen inorganic ions were analyzed after the UV exposure. WSON concentrations were calculated by the difference between the inorganic nitrogen concentrations before and after UV digestion. Ninety five percent of the aerosol samples collected in the suburban and pristine areas showed a WSON concentration range from 0.03 to 0.6 μg/m3 whereas in urban areas the range was 0.21 to 1.09 μg/m3. These concentration values are on the same order of magnitude than the previously found in other tropical and subtropical areas. The contribution of aerosol WSON to the total soluble nitrogen in the coastal urban, sub-urban and pristine areas ranged from 23 to 67%, while in Caracas was smaller (38±8%, n=5). Therefore, aerosol WSON provides an important source of nitrogen to these pristine and suburban ecosystems, which could potentially have implications on the nutrient cycling. There was a statistically significant linear correlation between the aerosol WSON and the water soluble inorganic

  12. Climate, soil organic layer, and nitrogen jointly drive forest development after fire in the North American boreal zone

    Science.gov (United States)

    Trugman, A. T.; Fenton, N. J.; Bergeron, Y.; Xu, X.; Welp, L. R.; Medvigy, D.

    2016-09-01

    Previous empirical work has shown that feedbacks between fire severity, soil organic layer thickness, tree recruitment, and forest growth are important factors controlling carbon accumulation after fire disturbance. However, current boreal forest models inadequately simulate this feedback. We address this deficiency by updating the ED2 model to include a dynamic feedback between soil organic layer thickness, tree recruitment, and forest growth. The model is validated against observations spanning monthly to centennial time scales and ranging from Alaska to Quebec. We then quantify differences in forest development after fire disturbance resulting from changes in soil organic layer accumulation, temperature, nitrogen availability, and atmospheric CO2. First, we find that ED2 accurately reproduces observations when a dynamic soil organic layer is included. Second, simulations indicate that the presence of a thick soil organic layer after a mild fire disturbance decreases decomposition and productivity. The combination of the biological and physical effects increases or decreases total ecosystem carbon depending on local conditions. Third, with a 4°C temperature increase, some forests transition from undergoing succession to needleleaf forests to recruiting multiple cohorts of broadleaf trees, decreasing total ecosystem carbon by ˜40% after 300 years. However, the presence of a thick soil organic layer due to a persistently mild fire regime can prevent this transition and mediate carbon losses even under warmer temperatures. Fourth, nitrogen availability regulates successional dynamics; broadleaf species are less competitive with needleleaf trees under low nitrogen regimes. Fifth, the boreal forest shows additional short-term capacity for carbon sequestration as atmospheric CO2 increases.

  13. Surveillance of healthcare acquired infections in hospital and community: a retrospective study in Local Healthcare Organization of Rovigo

    Directory of Open Access Journals (Sweden)

    Francesca Ronzani

    2013-03-01

    Full Text Available Background: antimicrobial resistance is recognized as one of the greatest threats to human health worldwide. Infections caused by multidrug-resistant bacteria are associated with higher incidences of mortality, morbidity, prolonged hospital stay and increase of costs. Surveillance of alert organism/conditions and bacterial resistance to antimicrobials is a systematic and dynamic system of data collection that analyses and monitors trends of bacterial resistance. This study was conducted to detect antimicrobial susceptibility patterns in order to inform treatment choices and generate hospital-wide baseline data.Methods: the Local Healtcare Oganization of Rovigo has started a program of surveillance on antimicrobial resistance in hospital and community. In this work some results of the surveillance of microorganism isolated and related antimicrobial resistance are reported, collected in the period 2009-2010 in Rovigo and Trecenta Hospitals, Territorial Nursing Homes (TNH and community from patients’ blood, urine and respiratory samples.Results: data show a significant difference in the level of antibiotic resistance between the two Hospitals. High rates of extended-spectrum β-lactamase (ESBL-producing organisms are detected and carbapenems are the only reliable agents for the treatment of many infections in the Hospital of Trecenta and TNH.Conclusions: because ESBL producing bacteria are emerging pathogens in the community, the rational use of available antibiotics or the appropriate antimicrobial prescribing are imperative. Local surveillance is a powerful tool to detect and monitor hospital and community infections and provides information useful as a guide to medical practice, including therapeutics and disease-control activities.

  14. Agronomic performance and chemical response of sunflower ( Helianthus annuus L.) to some organic nitrogen sources and conventional nitrogen fertilizers under sandy soil conditions

    Energy Technology Data Exchange (ETDEWEB)

    Helmy, A. M.; Fawzy Ramadan, M. F.

    2009-07-01

    Sunflower ( Helianthus annuus L.) is an option for oilseed production, particularly in dry land areas due to good root system development. In this study, two field experiments were performed in the El-Khattara region (Sharkia Governorate, Egypt) during the 2005 season. The objective of this research was to determine the effect of organic nitrogen (ON) sources and their combinations as well as to compare the effect of ON and ammonium sulfate (AS) as a conventional fertilizer added individually or in combination on growth, yield components, oil percentage and the uptake of some macro nutrients by sunflowers grown on sandy soil.The treatments of chicken manure (CM) and a mixture of farmyard manure (FYM) with CM were superior to the other treatments and gave the highest yield, dry matter yield, NPK uptake by plants at all growth stages along with seed yield at the mature stage. The effect of the different ON on crop yield and its components may follow the order; CM> palma residues (PR)> FYM. This was more emphasized when the materials were mixed with AS at a ratio of 3:1 and 1:1. The uptake of nitrogen (N), phosphorus (P) and potassium (K) by plants was affected by the addition of different N sources and treatments. The highest nutrient content and uptake by straw were obtained when treated with CM followed by PR at all growth stages, while it was PR followed by CM for seeds. Oil recovery was shown to respond to the N supply and the changes in individual fatty acids were not statistically different. However, it seems that the application of organic fertilizers resulted in an increase in total unsaturated fatty acids compared to the control. (Author) 58 refs.

  15. Molecular and structural characterization of dissolved organic matter from the deep ocean by FTICR-MS, including hydrophilic nitrogenous organic molecules

    Science.gov (United States)

    Reemtsma, T.; These, A.; Linscheid, M.; Leenheer, J.; Spitzy, A.

    2008-01-01

    Dissolved organic matter isolated from the deep Atlantic Ocean and fractionated into a so-called hydrophobic (HPO) fraction and a very hydrophilic (HPI) fraction was analyzed for the first time by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) to resolve the molecular species, to determine their exact masses, and to calculate their molecular formulas. The elemental composition of about 300 molecules was identified. Those in the HPO fraction (14C age of 5100 year) are very similar to much younger freshwater fulvic acids, but less aromatic and more oxygenated molecules are more frequent. This trend continues toward the HPI fraction and may indicate biotic and abiotic aging processes that this material experienced since its primary production thousands of years ago. In the HPI fraction series of nitrogenous molecules containing one, two, or three nitrogens were identified by FTICR-MS. Product ion spectra of the nitrogenous molecules suggest that the nitrogen atoms in these molecules are included in the (alicyclic) backbone of these molecules, possibly in reduced form. These mass spectrometric data suggest that a large set of stable fulvic acids is ubiquitous in all aquatic compartments. Although sources may differ, their actual composition and structure appears to be quite similar and largely independent from their source, because they are the remainder of intensive oxidative degradation processes. ?? 2008 American Chemical Society.

  16. Inorganic Nitrogen Leaching from Organic and Conventional Rice Production on a Newly Claimed Calciustoll in Central Asia

    DEFF Research Database (Denmark)

    Meng, Fanqiao; Olesen, Jørgen E; Sun, Xiangping

    2014-01-01

    . NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21–42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments......Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems...... flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization...

  17. Spatial Patterns of Soil Organic Carbon and Total Nitrogen in Mesquite Coppice Dunes

    Science.gov (United States)

    Ebbs, L. M.; Throop, H. L.

    2008-12-01

    Woody encroachment, an increase in woody plant abundance in formerly grass-dominated ecosystems, has occurred in semi-arid and arid systems worldwide over the past century. Woody encroachment has emerged as a potentially important, but highly uncertain, component of the North American carbon sink. The effects of woody plant encroachment on soil organic carbon (SOC) and total nitrogen (TN) relative to Prosopis velutina have been explored in the Sonoran Desert, where strong spatial patterns in SOC and TN based on shrub size and subcanopy location exist. Encroachment of Prosopis glandulosa in sandy soils in the Chihuahuan Desert leads to coppice dune formation. We applied spatially-intensive soil sampling methods around P. glandulosa dunes in the Chihuahuan Desert to see how spatial patterns differed from patterns in the Sonoran Desert, where dunes do not form. Approximately 15 soil cores were taken from within and around each of 13 dunes and analyzed for bulk density, SOC, and TN. The aboveground biomass of P. glandulosa in coppice dunes was also collected for a comparison of aboveground biomass and SOC pools. Intercanopy soils had greater bulk density than soils within dunes (P<0.05), although bulk density did not vary predictably with dune size or with spatial position within each dune. No predictable within-dune SOC or TN patterns were found. Within-dune SOC and TN concentrations were significantly greater than intercanopy values (P<0.001 for both SOC and TN). There was a strong positive linear relationship between dune area and aboveground biomass (R2=0.662, P<0.007). These relationships can be used to predict SOC, TN, and aboveground biomass in coppice dunes. In contrast to patterns in the Sonoran Desert with P. velutina, predicting SOC and TN in the P. glandulosa coppice dunes does not require information on individual dune size or spatial position. The differences in SOC and TN accumulation patterns beneath P. velutina and P. glandulosa may result from

  18. Removal of organic matter and nitrogen from distillery wastewater by a combination of methane fermentation and denitrification/nitrification processes.

    Science.gov (United States)

    Li, Jun; Zhang, Zhen-jia; Li, Zhi-rong; Huang, Guang-yu; Abe, Naoki

    2006-01-01

    The distillery wastewater of Guangdong Jiujiang Distillery, which is characteristic of containing high organic matters and rich total nitrogen, was treated by a combination of methane fermentation and denitrification/nitrification processes. 80% of COD in the raw wastewater was removed by methane fermentation at the COD volumetric loading rate of 20 kg COD/(m3 x d) using the expanded granule sludge bed (EGSB) process. However, almost all the organic nitrogen in the raw wastewater was converted into ammonia by ammonification there. Ammonia and volatile fatty acids (VFA) remaining in the anaerobically treated wastewater were simultaneously removed utilizing VFA as an electron donor by denitrification occurring in the other EGSB reactor and nitrification using PEG-immobilized nitrifying bacteria with recirculation process. An aerobic biological contact oxidization reactor was designed between denitrification/nitrification reactor for further COD removal. With the above treatment system, 18000-28000 mg/L of COD in raw wastewater was reduced to less than 100 mg/L. Also, ammonia in the effluent of the system was not detected and the system had a high removal rate for 900-1200 mg/L of TN in the raw wastewater, only leaving 400 mg/L of nitrate nitrogen.

  19. Removal of organic matter and nitrogen from distillery wastewater by a combination of methane fermentation and denitrification/nitrification processes

    Institute of Scientific and Technical Information of China (English)

    LI Jun; ZHANG Zhen-jia; LI Zhi-rong; HUANG Guang-yu; Naoki Abe

    2006-01-01

    The distillery wastewater of Guangdong Jiujiang Distillery, which is characteristic of containing high organic matters and rich total nitrogen, was treated by a combination of methane fermentation and denitrification/nitrification processes. 80% of COD in the raw wastewater was However, almost all the organic nitrogen in the raw wastewater was converted into ammonia by ammonification there. Ammonia and volatile fatty acids (VFA) remaining in the anaerobically treated wastewater were simultaneously removed utilizing VFA as an electron donor by denitrification occurring in the other EGSB reactor and nitrification using PEG-immobilized nitrifying bacteria with recirculation process. An aerobic biological contact oxidization reactor was designed between denitrification/nitrification reactor for further COD removal. With the above treatment system,18000-28000 mg/L of COD in raw wastewater was reduced to less than 100 mg/L. Also, ammonia in the effluent of the system was not detected and the system had a high removal rate for 900-1200 mg/L of TN in the raw wastewater, only leaving 400 mg/L of nitrate nitrogen.

  20. Dissolved Organic Nitrogen Inputs from Wastewater Treatment Plant Effluents Increase Responses of Planktonic Metabolic Rates to Warming.

    Science.gov (United States)

    Vaquer-Sunyer, Raquel; Conley, Daniel J; Muthusamy, Saraladevi; Lindh, Markus V; Pinhassi, Jarone; Kritzberg, Emma S

    2015-10-06

    Increased anthropogenic pressures on coastal marine ecosystems in the last century are threatening their biodiversity and functioning. Global warming and increases in nutrient loadings are two major stressors affecting these systems. Global warming is expected to increase both atmospheric and water temperatures and increase precipitation and terrestrial runoff, further increasing organic matter and nutrient inputs to coastal areas. Dissolved organic nitrogen (DON) concentrations frequently exceed those of dissolved inorganic nitrogen in aquatic systems. Many components of the DON pool have been shown to supply nitrogen nutrition to phytoplankton and bacteria. Predictions of how global warming and eutrophication will affect metabolic rates and dissolved oxygen dynamics in the future are needed to elucidate their impacts on biodiversity and ecosystem functioning. Here, we experimentally determine the effects of simultaneous DON additions and warming on planktonic community metabolism in the Baltic Sea, the largest coastal area suffering from eutrophication-driven hypoxia. Both bacterioplankton community composition and metabolic rates changed in relation to temperature. DON additions from wastewater treatment plant effluents significantly increased the activation energies for community respiration and gross primary production. Activation energies for community respiration were higher than those for gross primary production. Results support the prediction that warming of the Baltic Sea will enhance planktonic respiration rates faster than it will for planktonic primary production. Higher increases in respiration rates than in production may lead to the depletion of the oxygen pool, further aggravating hypoxia in the Baltic Sea.

  1. Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

    Digital Repository Service at National Institute of Oceanography (India)

    Maya, M.V; Karapurkar, S.G.; Naik, H.; Roy, R.; Shenoy, D.M.; Naqvi, S.W.A.

    decreasing trend despite an apparent intensification of seasonal oxygen deficiency over the past few decades? A secondary objective was to evaluate the sources of organic carbon. Elemental carbon and nitrogen concentrations, C/N ratios in SPOM, along...

  2. Distribution and sources of organic carbon, nitrogen and their isotopic signatures in sediments from the Ayeyarwady (Irrawaddy) continental shelf, northern Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Gaye, B.; Shirodkar, P.V.; Rao, P.S.; Chivas, A.R.; Wheeler, D.; Thwin, S.

    Total organic carbon (TOC), total nitrogen (TN) and their delta sup(13) C and delta sup (15) N values were determined from 110 sediment samples from the Ayeyarwady (Irrawaddy) continental shelf, northern Andaman Sea to decipher the concentration...

  3. Advanced removal of organic and nitrogen from ammonium-rich landfill leachate using an anaerobic-aerobic system☆

    Institute of Scientific and Technical Information of China (English)

    Hongwei Sun; Huanan Zhao; Baoxia Bai; Yuying Chen; Qing Yang; Yongzhen Peng

    2015-01-01

    A novel system coupling an up-flow anaerobic sludge blanket (UASB) and sequencing batch reactor (SBR) was introduced to achieve advanced removal of organic and nitrogen from ammonium-rich landfill leachate. UASB could remove 88.1%of the influent COD at a volumetric loading rate of 6.8 kg COD·m−3·d−1. Nitritation–denitritation was responsible for removing 99.8%of NH4+-N and 25%of total nitrogen in the SBR under alternating aerobic/anoxic modes. Simultaneous denitritation and methanogenesis in the UASB enhanced COD and TN removal, and replenished alkalinity consumed in nitritation. For the activated sludge of SBR, ammonia oxidizing bacteria were preponderant in nitrifying population, indicated by fluorescence in situ hybridization (FISH) anal-ysis. The Monod equation is appropriate to describe the kinetic behavior of heterotrophic denitrifying bacteria, with its kinetic parameters determined from batch experiments.

  4. Formation of nitrate and ammonium ions in titanium dioxide mediated photocatalytic degradation of organic compounds containing nitrogen atoms

    Energy Technology Data Exchange (ETDEWEB)

    Low, G.K.-C.; McEvoy, S.R.; Matthews, R.W. (CSIRO Division of Coal and Energy Technology, Menai (Australia))

    1991-03-01

    The photocatalytic oxidation of a related series of primary, secondary, and tertiary amines and other nitrogen- and sulfur-containing organic compounds over a UV-illuminated film of TiO{sub 2} has been studied. The compounds were as follows: n-pentylamine, piperidine, pyridine, phenylalanine, desipramine, thioridazine, penicillamine, isosorbide dinitrate, 4-nitrocatechol, 2,4-dinitrophenol, cyclophosphamide, 5-fluorouracil, atrazine, ethylenediaminetetracetic acid, and tetrabutylammonium phosphate. Both ammonium and nitrate ions were formed. The relative concentration of the two ions depended on the nature of the nitrogen in a compound, but was also influenced by the illumination time and concentration of the solute. It was found that for n-pentylamine, piperidine and pyridine, the rate of formation of ammonium ions was n-pentylamine {much gt} pyridine > piperidine. The order of rates of nitrate formation was pyridine = piperidine {much gt} pentylamine. For n-pentylamine the rate of formation of ammonium ions was {approximately}100 times that of nitrate.

  5. Organic carbon, phosphorus and nitrogen in surface sediments of the marine-coastal region north and south of the Paria Peninsula, Venezuela

    OpenAIRE

    Martínez-Soto, M. C.; Martínez, Gregorio

    2012-01-01

    The organic carbon, phosphorus and nitrogen content of silt and clay fractions of surface sediments from the marine-coastal region north and south of the Paria Peninsula (PP) were quantified. Organic carbon concentrations (Corg) were determined by dry combustion after decarbonation with 10% hydrochloric acid, and total phosphorus (TP) and total nitrogen (TN). This information was then used to produce maps of the iso-concentrations of the distribution of these elements in the sub-marine contin...

  6. Organization of biogeochemical nitrogen pathways with switch-like adjustment in fluctuating soil redox conditions

    Science.gov (United States)

    Lamba, Sanjay; Bera, Soumen; Rashid, Mubasher; Medvinsky, Alexander B.; Acquisti, Claudia; Li, Bai-Lian

    2017-01-01

    Nitrogen is cycled throughout ecosystems by a suite of biogeochemical processes. The high complexity of the nitrogen cycle resides in an intricate interplay between reversible biochemical pathways alternatively and specifically activated in response to diverse environmental cues. Despite aggressive research, how the fundamental nitrogen biochemical processes are assembled and maintained in fluctuating soil redox conditions remains elusive. Here, we address this question using a kinetic modelling approach coupled with dynamical systems theory and microbial genomics. We show that alternative biochemical pathways play a key role in keeping nitrogen conversion and conservation properties invariant in fluctuating environments. Our results indicate that the biochemical network holds inherent adaptive capacity to stabilize ammonium and nitrate availability, and that the bistability in the formation of ammonium is linked to the transient upregulation of the amo-hao mediated nitrification pathway. The bistability is maintained by a pair of complementary subsystems acting as either source or sink type systems in response to soil redox fluctuations. It is further shown how elevated anthropogenic pressure has the potential to break down the stability of the system, altering substantially ammonium and nitrate availability in the soil, with dramatic effects on biodiversity. PMID:28280580

  7. Invasiveness of Campylopus introflexus in drift sands depends on nitrogen deposition and soil organic matter

    NARCIS (Netherlands)

    Sparrius, L.B.; Kooijman, A.M.

    2011-01-01

    Question: Does the neophyte moss Campylopus introflexus invade more often in drift sand pioneer vegetations under high nitrogen (N) deposition? Location: Fourteen inland dune reserves in The Netherlands over a gradient of atmospheric N deposition. Methods: A transect study, dispersal experiment and

  8. Ambient Observations of Organic Nitrogen Compounds in Submicrometer Aerosols in New York Using High Resolution Aerosol Mass Spectrometry

    Science.gov (United States)

    Zhou, S.; Ge, X.; Xu, J.; Sun, Y.; Zhang, Q.

    2015-12-01

    Organic nitrogen (ON) compounds, which include amines, nitriles, organic nitrates, amides, and N-containing aromatic heterocycles, are an important class of compounds ubiquitously detected in atmospheric particles and fog and cloud droplets. Previous studies indicate that these compounds can make up a significant fraction (20-80%) of the total nitrogen (N) content in atmospheric condensed phases and play important roles in new particle formation and growth and affecting the optical and hygroscopicity of aerosols. In this study, we report the observation of ON compounds in submicrometer particles (PM1) at two locations in New York based on measurements using Aerodyne high-resolution time-of-flight mass spectrometer (HR-ToF-AMS). One study was conducted as part of the US Department of Energy funded Aerosol Lifecyle - Intensive Operation Period (ALC-IOP) campaign at Brookhaven National Lab (BNL, 40.871˚N, 72.89˚W) in summer, 2011 and the other was conducted at the Queen's College (QC) in New York City (NYC) in summer, 2009. We observed a notable amount of N-containing organic fragment ions, CxHyNp+ and CxHyOzNp+, in the AMS spectra of organic aerosols at both locations and found that they were mainly associated with amino functional groups. Compared with results from lab experiments, the C3H8N+ at m/z = 58 was primarily attributed to trimethylamine. In addition, a significant amount of organonitrates was observed at BNL. Positive matrix factorization (PMF) analysis of the high resolution mass spectra (HRMS) of organic aerosols identified a unique nitrogen-enriched OA (NOA) factor with elevated nitrogen-to-carbon (N/C) at both BNL and QC. Analysis of the size distributions, volatility profiles, and correlations with external tracer indicates that acid-base reactions of amino compounds with sulfate and acidic gas were mainly responsible for the formation of amine salts. Photochemical production was also observed to play a role in the formation of NOA. Bivariate polar

  9. Carbon Sequestration and Nitrogen Mineralization in Soil Cooperated with Organic Composts and Bio-char During Corn (Zea mays) Cultivation

    Science.gov (United States)

    Shin, Joung-Du; Lee, Sun-Ill; Park, Wu-Gyun; Choi, Yong-Su; Hong, Seong-Gil; Park, Sang-Won

    2014-05-01

    Objectives of this study were to estimate the carbon sequestration and to evaluate nitrogen mineralization and nitrification in soils cooperated with organic composts and bio-char during corn cultivation. For the experiment, the soil used in this study was clay loam types, and application rates of chemical fertilizer and bio-char were recommended amount after soil test and 2 % to soil weight, respectively. The soil samples were periodically taken at every 15 day intervals during the experimental periods. The treatments were consisted of non-application, cow manure compost, pig manure compost, swine digestate from aerobic digestion system, their bio-char cooperation. For the experimental results, residual amount of inorganic carbon was ranged from 51 to 208kg 10a-1 in soil only cooperated with different organic composts. However it was estimated to be highest at 208kg 10a-1 in the application plot of pig manure compost. In addition to bio-char application, it was ranged from 187.8 to 286kg 10a-1, but was greatest accumulated at 160.3kg 10a-1 in the application plot of cow manure compost. For nitrogen mineralization and nitrification rates, it was shown that there were generally low in the soil cooperated with bio-char compared to the only application plots of different organic composts except for 71 days after sowing. Also, they were observed to be highest in the application plot of swine digestate from aerobic digestion system. For the loss of total inorganic carbon (TIC) by run-off water, it was ranged from 0.18 to 0.36 kg 10a-1 in the different treatment plots. Also, with application of bio-char, total nitrogen was estimated to be reduced at 0.42(15.1%) and 0.38(11.8%) kg 10a-1 in application plots of the pig manure compost and aerobic digestate, respectively.

  10. Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results

    Energy Technology Data Exchange (ETDEWEB)

    Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

    1990-08-01

    This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program`s Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

  11. Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results

    Energy Technology Data Exchange (ETDEWEB)

    Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

    1990-08-01

    This report presents estimates of monthly sulfur dioxide (SO{sub 2}), nitrogen oxides (NO{sub x}), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program's Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment.

  12. Influence of different fertilization on the dissolved organic carbon, nitrogen and phosphorus accumulation in acid and limed soils

    Directory of Open Access Journals (Sweden)

    Ieva Jokubauskaite

    2015-04-01

    Full Text Available Soil quality has become an important issue in soil science. Dissolved organic carbon (DOC is believed to play an important role in soil processes and in the C, N and P balances, their supplies to plants in all types of soils. It is much more sensitive to soil management than is soil organic matter as a whole, and can be used as a key indicator of soil natural functions. This study aimed to assess the influence of different organic fertilizers on DOC and N, P accumulation. The study was carried out on a moraine loam soil at the Vezaiciai Branch of Lithuanian Research Centre for Agriculture and Forestry in 2012. Farmyard manure (FYM (60 t ha -1 and alternative organic fertilizers (wheat straw, rape residues, roots, stubble, perennial grasses were applied on two soil backgrounds - acid and limed. DOC was analysed using an ion chromatograph SKALAR. Application of organic amendments resulted in a significant increase of soil organic carbon (SOC content, which demonstrates a positive role of organic fertilizers in SOC conservation. The combination of different organic fertilizers and liming had a significant positive effect on DOC concentration in the soil. The highest DOC content (0.241 g kg-1 was established in the limed soil fertilized with farmyard manure. The most unfavourable status of DOC was determined in the unlimed, unfertilized soil. The limed and FYM-applied soil had the highest nitrogen (1.47 g kg-1 and phosphorus (0.84 g kg-1 content compared to the other treatments. Organic fertilizers gave a significant positive effect on SOC and DOC content increase in the topsoil. This immediate increase is generally attributed to the presence of soluble materials in the amendments. Application of organic fertilizers in acid and limed soil increased the nutrient stocks and ensured soil chemical indicators at the optimal level for plant growth and thus may provide a mechanism as well as prediction opportunities for soil fertility, conservation

  13. Influence of nitrogen status on the bioconcentration of hydrophobic organic compounds to Selenastrum capricornutum

    DEFF Research Database (Denmark)

    Halling-Sørensen, B.; Nyholm, Niels; Kusk, Kresten Ole

    2000-01-01

    - creased from 17 to 44% of the algal dry weight as a consequence of nitrogen starvation. An increase in total lipid from 17 to 44% should theoretically increase the BCFs by a factor of 2.6. BCFs for PCB 31, PCB 49, PCB 153, and DDT increased with maximum lipid content by factors of 6.3, 8.9, 8.9, and 6...

  14. Organic and Inorganic Nitrogen Fertilization Effects on Some Physiological and Agronomical Traits of Chickpea (Cicer arietinum L. in Irrigated Condition

    Directory of Open Access Journals (Sweden)

    Ali Namvar

    2013-09-01

    Full Text Available The effects of organic and inorganic nitrogen fertilization on some physiological and agronomical traits of chickpea (Cicer arietinum L. cv. ILC 482, investigated at the Experimental Farm of the Agriculture Faculty, University of Mohaghegh Ardabili. The trial was laid out in spilt plot design based on randomized complete block with four replications. Experimental factors were mineral nitrogen fertilizer at four levels (0, 50, 75 and 100 kg urea/ha in the main plots, and two levels of inoculation with Rhizobium bacteria (with and without inoculation as sub plots. N application and Rh. inoculation showed positive effects on physiological and agronomical traits of chickpea. The highest value of leaf RWC recorded in 50 kg urea/ha that was statistically in par with 75 kg urea/ha application while, usage of 75 kg urea/ha showed the maximum stem RWC. The maximum CMS obtained form application of 75 kg urea/ha. Chlorophyll content, leaf area index and grains protein content showed their maximum values in the highest level of nitrogen usage (100 kg urea/ha. Moreover, inoculated plants had the highest magnitudes of all physiological traits. In the case of agronomical traits, the highest values of plant height, number of primary and secondary branches, number of pods per plant, number of grains per plant, grain and biological yield were obtained from the highest level of nitrogen fertilizer (100 kg urea/ha and Rh. inoculation. Application of 75 kg urea/ha was statistically in par with 100 kg urea/ha in all of these traits. The results pointed out that some N fertilization (i.e. between 50 and 75 kg urea/ha as starter can be beneficial to improve growth, development, physiological traits and total yield of inoculated chickpea.

  15. Atmospheric organic and inorganic nitrogen inputs to coastal urban and montane Atlantic Forest sites in southeastern Brazil

    Science.gov (United States)

    de Souza, Patricia A.; Ponette-González, Alexandra G.; de Mello, William Z.; Weathers, Kathleen C.; Santos, Isimar A.

    2015-06-01

    Tropical regions are currently experiencing changes in the quantity and form of nitrogen (N) deposition as a result of urban and industrial emissions. We quantified atmospheric N inputs to two coastal urban and two montane (400 m and 1000 m) Atlantic Forest sites downwind of the Metropolitan Region of Rio de Janeiro (MRRJ), Brazil, from August 2008 to August 2009. Concentrations of total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN) and urea were measured in bulk precipitation at all sites, as well as in canopy throughfall in the lower montane forest. Dissolved organic nitrogen (DON) was calculated as the difference between TDN and DIN (NH4+ + NO3- + NO2-). Annual volume-weighted mean bulk concentrations of all N species were higher at the coastal urban than montane forest sites, with DON accounting for 32-56% and 26-32%, respectively, of the TDN concentration in bulk precipitation. Bulk deposition of TDN ranged 12.1-17.2 kg N ha- 1 yr- 1 and tended to decrease with increasing distance from the coastal urban region. In the lower montane forest, throughfall TDN flux, 34.3 kg N ha- 1 yr- 1, was over 2-fold higher than bulk TDN deposition, and DON comprised 57% of the total N deposited by throughfall to the forest soil. Urea comprised 27% of DON in throughfall compared to up to 100% in bulk precipitation. Our findings show that DON is an important, yet understudied, component of TDN deposition in tropical forest regions, comprising one-third to greater than one-half of the N deposited in rainfall and throughfall. Further, in this lower montane Atlantic Forest site, throughfall DIN flux was 1.5-3 fold higher than the suggested empirical critical load for humid tropical forests, highlighting the potential for increasing N pollution emitted from the MRRJ to impact N cycling in adjacent ecosystems.

  16. Impacts of traditional land use practices on soil organic carbon and nitrogen pools of mountain ecosystems in Nepal

    Science.gov (United States)

    Giri, Anjana; Katzensteiner, Klaus

    2010-05-01

    Crop production, animal husbandry and forestry are three closely interlinked components of land use systems in the mountains of Nepal. Forests are the major source of fuel wood, construction materials, fodder and litter. The latter is used as a bedding material for livestock and forms an important component of farmyard manure. In addition forest grazing by cattle is a common practice. Excessive extraction of biomass from the forest leads to a decline of soil organic matter and nutrient contents. On the landscape scale these negative effects will partly be compensated by positive effects on soil organic matter and nutrient stocks of arable soils. The experimental data base for a quantification of such effects at the scale of communities is however poor, in particular for Nepal. Understanding the impact of subsistence farming on ecosystems is imperative in order to recommend successful and sustainable land management practices. The aim of our study is to quantify effects of land use on carbon and nitrogen pools and fluxes for mountain communities in Nepal. Results of a case study in the buffer zone area of the Sagarmatha National Park are presented. The potential vegetation comprises mixed forests of Quercus semicarpifolia, Rhododendron arboreum and Tsuga dumosa. Carbon and nitrogen stocks in soil and vegetation were quantified for three different land use types, namely: forest with low human impact, forests with high human impact and agricultural land. The scale of disturbance of the forests has been classified by visual estimation considering the percentage of litter raked, number of lopped trees, and grazing intensity assessed by signs of trampling and the number of trails. After stratification of the community area, 20 plots of 10 m radius were established (17 forest plots, 3 plots for arable land) where biometric data of the vegetation were determined and sub-samples were taken for chemical analyses. Organic layers (litter remaining after litter raking) and soil

  17. Effects of Organic and Inorganic Nitrogen on the Growth and Production of Domoic Acid by Pseudo-nitzschia multiseries and P. australis (Bacillariophyceae in Culture

    Directory of Open Access Journals (Sweden)

    Véronique Martin-Jézéquel

    2015-11-01

    Full Text Available Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine. Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen sources induced broad differences between the two species with respect to growth rate, biomass and cellular DA, but no specific variation could be attributed to any of the inorganic or organic nitrogen substrates. Enrichment with ammonium resulted in an enhanced growth rate and cell yield, whereas glutamate did not support the growth of P. multiseries. Arginine, glutamine and taurine enabled good growth of P. australis, but without toxin production. The highest DA content was produced when P. multiseries grew with urea and P. australis grew with glutamate. For both species, growth rate was not correlated with DA content but more toxin was produced when the nitrogen source could not sustain a high biomass. A significant negative correlation was found between cell biomass and DA content in P. australis. This study shows that Pseudo-nitzschia can readily utilize organic nitrogen in the form of amino acids, and confirms that both inorganic and organic nitrogen affect growth and DA production. Our results contribute to our understanding of the ecophysiology of Pseudo-nitzschia spp. and may help to predict toxic events in the natural environment.

  18. Effects of Organic and Inorganic Nitrogen on the Growth and Production of Domoic Acid by Pseudo-nitzschia multiseries and P. australis (Bacillariophyceae) in Culture

    Science.gov (United States)

    Martin-Jézéquel, Véronique; Calu, Guillaume; Candela, Leo; Amzil, Zouher; Jauffrais, Thierry; Séchet, Véronique; Weigel, Pierre

    2015-01-01

    Over the last century, human activities have altered the global nitrogen cycle, and anthropogenic inputs of both inorganic and organic nitrogen species have increased around the world, causing significant changes to the functioning of aquatic ecosystems. The increasing frequency of Pseudo-nitzschia spp. in estuarine and coastal waters reinforces the need to understand better the environmental control of its growth and domoic acid (DA) production. Here, we document Pseudo-nitzschia spp. growth and toxicity on a large set of inorganic and organic nitrogen (nitrate, ammonium, urea, glutamate, glutamine, arginine and taurine). Our study focused on two species isolated from European coastal waters: P. multiseries CCL70 and P. australis PNC1. The nitrogen sources induced broad differences between the two species with respect to growth rate, biomass and cellular DA, but no specific variation could be attributed to any of the inorganic or organic nitrogen substrates. Enrichment with ammonium resulted in an enhanced growth rate and cell yield, whereas glutamate did not support the growth of P. multiseries. Arginine, glutamine and taurine enabled good growth of P. australis, but without toxin production. The highest DA content was produced when P. multiseries grew with urea and P. australis grew with glutamate. For both species, growth rate was not correlated with DA content but more toxin was produced when the nitrogen source could not sustain a high biomass. A significant negative correlation was found between cell biomass and DA content in P. australis. This study shows that Pseudo-nitzschia can readily utilize organic nitrogen in the form of amino acids, and confirms that both inorganic and organic nitrogen affect growth and DA production. Our results contribute to our understanding of the ecophysiology of Pseudo-nitzschia spp. and may help to predict toxic events in the natural environment. PMID:26703627

  19. Molecular characterization of water soluble organic nitrogen in marine rainwater by ultra-high resolution electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    K. E. Altieri

    2011-11-01

    Full Text Available Atmospheric water soluble organic nitrogen (WSON is a subset of the complex organic matter in aerosols and rainwater, which impacts cloud condensation processes and aerosol chemical and optical properties, and may play a significant role in the biogeochemical cycle of N. However, its sources, composition, connections to inorganic N, and variability are largely unknown. Rainwater samples were collected on the island of Bermuda (32.27° N, 64.87° W, which experiences both anthropogenic and marine influenced air masses. Samples were analyzed by ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to chemically characterize the WSON. Elemental compositions of 2455 N containing compounds were determined over the mass range m/z+ 50 to 500. The five compound classes with the largest number of elemental formulas identified, in order from the highest number of formulas to the lowest, contained carbon, hydrogen, oxygen, and nitrogen (CHON+, CHON compounds that contained sulfur (CHONS+, CHON compounds that contained phosphorous (CHONP+, CHON compounds that contained both sulfur and phosphorous (CHONSP+, and compounds that contained only carbon, hydrogen, and nitrogen (CHN+. No organonitrates or nitrooxy-organosulfates were detected, but there was an increased presence of organic S and organic P containing compounds in the marine rainwater. Compared to rainwater collected in the continental USA, average O:C ratios of all N containing compound classes were lower in the marine samples whereas double bond equivalent values were higher, suggesting a reduced role of secondary formation mechanisms. Cluster analysis showed a clear chemical distinction between samples collected during the cold season (October to March which have anthropogenic air mass origins and samples collected during the warm season (April to September with remote marine air mass origins. This, in conjunction with patterns

  20. Molecular characterization of water soluble organic nitrogen in marine rainwater by ultra-high resolution electrospray ionization mass spectrometry

    Science.gov (United States)

    Altieri, K. E.; Hastings, M. G.; Peters, A. J.; Sigman, D. M.

    2012-04-01

    Atmospheric water soluble organic nitrogen (WSON) is a subset of the complex organic matter in aerosols and rainwater, which impacts cloud condensation processes and aerosol chemical and optical properties and may play a significant role in the biogeochemical cycle of N. However, its sources, composition, connections to inorganic N, and variability are largely unknown. Rainwater samples were collected on the island of Bermuda (32.27° N, 64.87° W), which experiences both anthropogenic and marine influenced air masses. Samples were analyzed by ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to chemically characterize the WSON. Elemental compositions of 2281 N containing compounds were determined over the mass range m/z+ 50 to 500. The five compound classes with the largest number of elemental formulas identified, in order from the highest number of formulas to the lowest, contained carbon, hydrogen, oxygen, and nitrogen (CHON+), CHON compounds that contained sulfur (CHONS+), CHON compounds that contained phosphorus (CHONP+), CHON compounds that contained both sulfur and phosphorus (CHONSP+), and compounds that contained only carbon, hydrogen, and nitrogen (CHN+). Compared to rainwater collected in the continental USA, average O:C ratios of all N containing compound classes were lower in the marine samples whereas double bond equivalent values were higher, suggesting a reduced role of secondary formation mechanisms. Despite their prevalence in continental rainwater, no organonitrates or nitrooxy-organosulfates were detected, but there was an increased presence of organic S and organic P containing compounds in the marine rainwater. Cluster analysis showed a clear chemical distinction between samples collected during the cold season (October to March) which have anthropogenic air mass origins and samples collected during the warm season (April to September) with remote marine air mass origins. This, in

  1. Soil organic carbon and nitrogen content of density fractions and effect of meadow degradation to soil carbon and nitrogen of fractions in alpine Kobresia meadow

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This research was conducted on the non-disturbed native alpine Kobresia meadow(YF) and the severely degraded meadow(SDL) of Dari County of Qinghai Province.By a density fractionation approach,each soil sample was divided into two fractions:light fraction(LF) and heavy fraction(HF).The obtained fractions were analyzed for organic carbon(OC) and nitrogen(N) concentrations.The results showed:(1) the OC concentration in HF and LF was 3.84% and 28.63% respectively while the nitrogen concentration in HF and LF was 0.362% and 1.192% respectively in 0-10 cm depth.C:N ratio was 10.6 in HF and 23.8 in LF respectively.(2) As far as the ratio of OC in given fraction to that in gross sample was concerned,dominance of OC in HF was obvious in the whole soil profile.OC in HF increased from 78.95% to 90.33%,while OC in LF decreased from 21.05% to 9.68% with depths.(3) Soil total OC amounted to 47.47 in YF while 17.63 g.kg-1 in SDL,in which the OC content in HF decreased from 37.31 to 16.01 g.kg-1 while OC content in LF decreased from 10.01 to 1.62 g.kg-1.In other words,results of OC and N content show meadow degradation led to the loss of 57% OC in HF and 84% OC in LF from originally native ecosystem on alpine meadow.In addition,meadow degradation led to the loss of 43% N in HF and 79% N in LF from originally native ecosystem on alpine meadow.(4) The main reason for loss of C and N in LF during meadow degradation was not attributed to the decrease of OC and N concentration in LF and LF,but to the decrease in LF dry weight.Loss of N was far lower than loss of C in HF.This may suggest that there is difference in protection mode of C and N in HF.

  2. Development of constructed wetlands in performance intensifications for wastewater treatment: a nitrogen and organic matter targeted review.

    Science.gov (United States)

    Wu, Shubiao; Kuschk, Peter; Brix, Hans; Vymazal, Jan; Dong, Renjie

    2014-06-15

    The knowledge on the performance enhancement of nitrogen and organic matter in the expanded constructed wetlands (CWs) with various new designs, configurations, and technology combinations are still not sufficiently summarized. A comprehensive review is accordingly necessary for better understanding of this state-of-the-art-technology for optimum design and new ideas. Considering that the prevailing redox conditions in CWs have a strong effect on removal mechanisms and highly depend on wetland designs and operations, this paper reviews different operation strategies (recirculation, aeration, tidal operation, flow direction reciprocation, and earthworm integration), innovative designs, and configurations (circular-flow corridor wetlands, towery hybrid CWs, baffled subsurface CWs) for the intensifications of the performance. Some new combinations of CWs with technologies in other field for wastewater treatment, such as microbial fuel cell, are also discussed. To improve biofilm development, the selection and utilization of some specific substrates are summarized. Finally, we review the advances in electron donor supply to enhance low C/N wastewater treatment and in thermal insulation against low temperature to maintain CWs running in the cold areas. This paper aims to provide and inspire some new ideas in the development of intensified CWs mainly for the removal of nitrogen and organic matter. The stability and sustainability of these technologies should be further qualified.

  3. Kinetics of organic molecules in pulsed plasmas of nitrogen or N2/O2 mixtures at near atmospheric pressure

    Science.gov (United States)

    Pasquiers, S.; Blin-Simiand, N.; Magne, L.

    2013-12-01

    In plasmas of atmospheric gases, the kinetics of some aliphatic organic molecules belonging to the hydrocarbons (propene, propane), aldehydes (acetaldehyde) and ketones (acetone) families were studied using a photo-triggered discharge (homogeneous plasma). It was shown that quenchings of N2 metastable states, A\\,^{3}\\Sigma_{u}^{+} and the group of singlets a'\\,^{1}\\Sigma_{u}^{-} , a 1Πg and w 1Δu, are important processes for the decomposition of such molecules. It plays a fundamental role in the nitrogen plasma, but it is also present in air. At low temperature, the oxidation reactions by the oxygen atom or by the hydroxyl radical are not always sufficiently effective to induce an increase of the molecule decomposition when oxygen is added to the nitrogen/organic mixture. For most cases, quenching processes appear purely dissociative. However, recent results obtained for propene lead to the conclusion that a non-dissociative exit route could exist. The quenching of the singlet states induces a break of the double bound C = O for the acetaldehyde and acetone molecules. Some kinetic analogies appear between filamentary and homogeneous plasmas, which could be very useful to get a comprehensive understanding of the physico-chemical processes in dielectric barriers or corona discharges used for various applications.

  4. A comparison of simultaneous organic carbon and nitrogen removal in microbial fuel cells and microbial electrolysis cells.

    Science.gov (United States)

    Hussain, Abid; Manuel, Michelle; Tartakovsky, Boris

    2016-05-15

    This study demonstrates simultaneous carbon and nitrogen removal in laboratory-scale continuous flow microbial fuel cell (MFC) and microbial electrolysis cell (MEC) and provides side-by side comparison of these bioelectrochemical systems. The maximum organic carbon removal rates in MFC and MEC tests were similar at 5.1 g L(-1) d(-1) and 4.16 g L(-1) d(-1), respectively, with a near 100% carbon removal efficiency at an organic load of 3.3 g L(-1) d(-1). An ammonium removal efficiency of 30-55% with near-zero nitrite and nitrate concentrations was observed in the MFC operated at an optimal external resistance, while open-circuit MFC operation resulted in a reduced carbon and ammonium removal of 53% and 21%, respectively. In the MEC ammonium removal was limited to 7-12% under anaerobic conditions, while micro-aerobic conditions increased the removal efficiency to 31%. Also, at zero applied voltage both carbon and ammonium removal efficiencies were reduced to 42% and 4%, respectively. Based on the observed performance under different operating conditions, it was concluded that simultaneous carbon and nitrogen removal was facilitated by concurrent anaerobic and aerobic biotransformation pathways at the anode and cathode, which balanced bioelectrochemical nitrification and denitrification reactions.

  5. Estimation of Corn Yield and Soil Nitrogen via Soil Electrical Conductivity Measurement Treated with Organic, Chemical and Biological Fertilizers

    Directory of Open Access Journals (Sweden)

    H. Khalilzade

    2016-02-01

    Full Text Available Introduction Around the world maize is the second crop with the most cultivated areas and amount of production, so as the most important strategic crop, have a special situation in policies, decision making, resources and inputs allocation. On the other side, negative environmental consequences of intensive consumption of agrochemicals resulted to change view concerning food production. One of the most important visions is sustainable production of enough food plus attention to social, economic and environmental aspects. Many researchers stated that the first step to achieve this goal is optimization and improvement of resources use efficiencies. According to little knowledge on relation between soil electrical conductivity and yield of maize, beside the environmental concerns about nitrogen consumption and need to replace chemical nitrogen by ecological inputs, this study designed and aimed to evaluate agroecological characteristics of corn and some soil characteristics as affected by application of organic and biological fertilizers under field conditions. Materials and Methods In order to probing the possibility of grain yield and soil nitrogen estimation via measurement of soil properties, a field experiment was conducted during growing season 2010 at Research Station, Ferdowsi University of Mashhad, Iran. A randomized complete block design (RCBD with three replications was used. Treatments included: 1- manure (30 ton ha-1, 2-vermicompost (10 ton ha-1, 3- nitroxin (containing Azotobacter sp. and Azospirillum sp., inoculation was done according to Kennedy et al., 4- nitrogen as urea (400 kg ha-1 and 5- control (without fertilizer. Studied traits were soil pH, soil EC, soil respiration rate, N content of soil and maize yield. Soil respiration rate was measured using equation 1: CO2= (V0- V× N×22 Equation 1 In which V0 is the volume of consumed acid for control treatment titration, V is of the volume of consumed acid for sample treatment

  6. Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration

    Directory of Open Access Journals (Sweden)

    Davi José Silva

    2016-01-01

    Full Text Available ABSTRACT Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf, a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments consisted of two rates of organic fertilizer (0 and 30 m3 ha-1 and five N rates (0, 10, 20, 40, and 80 kg ha-1, in a randomized block design arranged in split plots, with five replications. The organic fertilizer levels represented the main plots and the N levels, the subplots. The source of N was urea and the source of organic fertilizer was goat manure. Irrigation was applied through a drip system and N by fertigation. At the end of the third growing season, soil chemical properties were determined and nitrate concentration in the soil solution (extracted by porous cups was determined. Organic fertilization increased organic matter, pH, EC, P, K, Ca, Mg, Mn, sum of bases, base saturation, and CEC, but decreased exchangeable Cu concentration in the soil by complexation of Cu in the organic matter. Organic fertilization raised the nitrate concentration in the 0.20-0.40 m soil layer, making it leachable. Nitrate concentration in the soil increased as N rates increased, up to more than 300 mg kg-1 in soil and nearly 800 mg L-1 in the soil solution, becoming prone to leaching losses.

  7. Nitrogen isotopes as a screening tool to determine the growing regimen of some organic and nonorganic supermarket produce from New Zealand.

    Science.gov (United States)

    Rogers, Karyne M

    2008-06-11

    An isotopic study was performed on nine varieties of organically and conventionally grown vegetables from an organic food market and a chain supermarket in New Zealand. The main aim of the study was to assess the applicability of stable nitrogen isotopes as a screening tool to differentiate between organic and conventional growing conditions of various vegetable types sampled directly off supermarket shelves. This could be further used as the basis of a simple authentication tool to detect noncompliant organic farming practices and false labeling of organic produce. In this study, nitrogen isotopes are found to be an excellent way of identifying faster growing organic vegetables (maturity time to harvest of 80 days), more information would be required to understand isotopic variations and fractionation effects between vegetables and soil over time as the technique does not discriminate organic from conventional regimens for these vegetables with as much certainty.

  8. Dissolved Organic Nitrogen Composition and Reactivity as a Function of Surface Vegetation and Microbial Community Structure in Northern Minnesota Peatlands

    Science.gov (United States)

    Cooper, W. T.; Tfaily, M.; Podgorski, D.; Chanton, J.; Lin, X.; Kostka, J. E.

    2012-12-01

    Peatlands sequester one-third of all soil carbon and currently act as major sinks of atmospheric carbon dioxide. The ability to predict or simulate the fate of stored carbon in response to climatic disruption remains hampered by our limited understanding of the controls of carbon and nitrogen turnover and the composition and functioning of peatland microbial communities. Recent studies using some advanced analytical chemistry and microbial sequencing techniques, in particular ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) (Chanton et al., 2009; D'Andrilli J, et al.,2010) and bacterial/archaeal 16S rRNA sequencing (Lin X., et al., 2012) suggest that differences in enhanced carbon storage in northern peatlands that have been attributed to an inhibition of microbial metabolism can be identified and understood using this combined molecular-genetic approach. However, these studies have focused exclusively on dissolved organic carbon (DOC). In this presentation we report on similar molecular- and genetic-based studies that link microbial community structure and activity to the composition and reactivity of dissolved organic nitrogen (DON) in bog and fen sites dominated by contrasting plant species. These sites were located in the Glacial Lake Agassiz Peatland (GLAP) and Spruce and Peatland Response under Climatic and Environmental Change (SPRUCE) project area, both located in Northern Minnesota. Our study of DON reactivity was made possible by the recognition that positive- mode Atmospheric Pressure Photoionization (APPI) coupled to FT-ICR MS was able to selectively visualize the low-abundance organic nitrogen that is usually undetectable in the large background of dissolved organic carbon. This work was supported by grants from the National Science Foundation (NSF-EAR-0628349, NSF-DMR-06-54118) and Department of Energy (DE-SC0007144). Chanton JP, et al. (2008). Global Biogeochem Cy 22: GB4022, doi:4010.1029/2008GB003274. D

  9. Organic supplemental nitrogen sources for field corn production following a hairy vetch cover crop

    Science.gov (United States)

    The combined use of legume cover crops and animal byproduct organic amendments could provide agronomic and environmental benefits to organic farmers by increasing corn grain yield while optimizing N and P inputs. To test this hypothesis we conducted a two-year field study and a laboratory soil incu...

  10. Nitrogen Isotopic Composition of Organic Matter in a Pristine Collection IDP

    Science.gov (United States)

    Messenger, S.; Nakamura-Messenger, K.; Keller, L. P.; Clemett, S. J.; Nguyen, A. N.; Walker, Robert M.

    2012-01-01

    Anhydrous chondritic porous interplanetary dust particles (CP IDPs) are probable cometary materials that show primitive characteristics, such as unequilibrated mineralogy, fragile structure, and abundant presolar grains and organic matter [1-3]. CP IDPs are richer in aliphatic species and N-bearing aromatic hydrocarbons than meteoritic organics and commonly exhibit highly anomalous H and N isotopic compositions [4,5]. Cometary organic matter is of interest in part because it has escaped the hydrothermal processing experienced by meteorites. However, IDPs are collected using silicon oil that must be removed with strong organic solvents such as hexane. This procedure is likely to have removed some fraction of soluble organic phases in IDPs. We recently reported the first stratospheric collection of IDPs without the use of silicone oil [6]. Here we present initial studies of the carbonaceous material in an IDP from this collection.

  11. Nitrogen Substituted Polycyclic Aromatic Hydrocarbon As Capable Interstellar Infrared Spectrum Source Considering Astronomical Chemical Evolution Step To Biological Organic Purine And Adenine

    CERN Document Server

    Ota, Norio

    2016-01-01

    In order to find out capable chemical evolution step from astronomically created organic in interstellar space to biological organic on the earth, infrared spectrum of nitrogen substituted carbon pentagon-hexagon coupled polycyclic aromatic hydrocarbon was analyzed by the density functional theory. Ionization was modeled from neutral to tri-cation. Among one nitrogen and two nitrogen substituted NPAH, we could find good examples showing similar IR behavior with astronomically well observed one as like C8H6N1, C7H5N2, and C7H5N2. We can imagine that such ionized NPAH may be created in interstellar space by attacks of high energy nitrogen and photon. Whereas, in case of three and four nitrogen substituted cases as like C6H4N3 and C5H3N4, there were no candidate showing similar behavior with observed one. Also, IR of typical biological organic with four and five nitrogen substituted one as like purine and adenine resulted no good similarity with observed one. By such theoretical comparison, one capable story of ...

  12. Inorganic and organic nitrogen acquisition by a fern Dicranopteris dichotoma in a subtropical forest in South China.

    Directory of Open Access Journals (Sweden)

    Xingliang Xu

    Full Text Available The fern Dicranopteris dichotoma is an important pioneer species of the understory in Masson pine (Pinus massoniana forests growing on acidic soils in the subtropical and tropical China. To improve our understanding of the role of D. dichotoma in nitrogen (N uptake of these forests, a short-term (15N experiment was conducted at mountain ridge (MR, with low N level and mountain foot (MF, with high N level. We injected (15N tracers as (15NH4, (15NO3 or (15N-glycine into the soil surrounding each plant at both MR and MF sites. Three hours after tracer injection, the fern D. dichotoma took up 15NH4+ significantly faster at MF than at MR, but it showed significantly slower uptake of (15NO3- at MF than at MR. Consequently, (15NO3- made greater contribution to the total N uptake (50% to the total N uptake at MR than at MF, but (15N-glycine only contributed around 11% at both sites. Twenty-four hours after tracer injection, D. dichotoma preferred (15NH4+ (63% at MR, whereas it preferred (15NO3- (47% at MF. We concluded that the D. dichotoma responds distinctly in its uptake pattern for three available N species over temporal and spatial scales, but mainly relies on inorganic N species in the subtropical forest. This suggests that the fern employs different strategies to acquire available N which depends on N levels and time.

  13. Nitrogen export from a boreal stream network following forest harvesting: seasonal nitrate removal and conservative export of organic forms

    Science.gov (United States)

    Schelker, J.; Sponseller, R.; Ring, E.; Högbom, L.; Löfgren, S.; Laudon, H.

    2016-01-01

    Clear-cutting is today the primary driver of large-scale forest disturbance in boreal regions of Fennoscandia. Among the major environmental concerns of this practice for surface waters is the increased mobilization of nutrients, such as dissolved inorganic nitrogen (DIN) into streams. But while DIN loading to first-order streams following forest harvest has been previously described, the downstream fate and impact of these inputs is not well understood. We evaluated the downstream fate of DIN and dissolved organic nitrogen (DON) inputs in a boreal landscape that has been altered by forest harvests over a 10-year period. The small first-order streams indicated substantial leaching of DIN, primarily as nitrate (NO3-) in response to harvests with NO3- concentrations increasing by ˜ 15-fold. NO3- concentrations at two sampling stations further downstream in the network were strongly seasonal and increased significantly in response to harvesting at the mid-sized stream, but not at the larger stream. DIN removal efficiency, Er, calculated as the percentage of "forestry derived" DIN that was retained within the stream network based on a mass-balance model was highest during the snowmelt season followed by the growing season, but declined continuously throughout the dormant season. In contrast, export of DON from the landscape indicated little removal and was essentially conservative. Overall, net removal of DIN between 2008 and 2011 accounted for ˜ 65 % of the total DIN mass exported from harvested patches distributed across the landscape. These results highlight the capacity of nitrogen-limited boreal stream networks to buffer DIN mobilization that arises from multiple clear-cuts within this landscape. Further, these findings shed light on the potential impact of anticipated measures to increase forest yields of boreal forests, such as increased fertilization and shorter forest rotations, which may increase the pressure on boreal surface waters in the future.

  14. Predicting dissolved organic nitrogen export from a poorly drained loblolly pine plantation using the forestry version of DRAINMOD-NII

    Science.gov (United States)

    Tian, S.; Youssef, M. M.; Skaggs, R. W.; Chescheir, G. M.; Amatya, D. M.

    2010-12-01

    Dissolved organic nitrogen (DON) is one of the main nitrogen forms exported from terrestrial to aquatic ecosystems and it plays important ecological functions in receiving surface water bodies. The DRAINMOD-NII forestry model was developed to predict water, carbon and nitrogen dynamics in drained forest ecosystems. We present an extended version of the model to predict DON export from drained forested lands. A new module has been added to the model to describe key mechanisms and processes regulating DON losses from forested lands. DON production rates was linked to the surface letter and soil microbial compartments and root exudates. The Langmuir isotherm was used to quantify the assumed instantaneous equilibrium between DON in solid and aqueous phases. DON transport with groundwater flow is simulated using numerical solutions to the advection-dispersion-reaction equation. We calibrated and validated the modified model using 21 years of water flow and DON loading data measured at the outlets of three forested (loblolly pine plantations) watersheds located in eastern North Carolina, USA. Field-testing results indicated that the model is capable of reproducing DON export dynamics on both annual and monthly basis. Nash-Sutcliffe coefficients were above 0.70 for predicted annual DON losses and above 0.63 for monthly predictions. The good model performance is most likely attributed to accurate predictions of drainage rates and reasonable quantification of biotic and abiotic controls on DON dynamics. Although there are some uncertainties of assumptions and methods adapted by the model, the relatively accurate predictions of DON loads indicates a good performance of the model given the currently limited understanding of these inherent factors and mechanisms controlling DON dynamics.

  15. Comparison of Organic Matter Composition in Agricultural versus Forest Affected Headwaters with Special Emphasis on Organic Nitrogen

    DEFF Research Database (Denmark)

    Heinz, Marlen; Graeber, Daniel; Zak, Dominik;

    2015-01-01

    Agricultural management practices promote organic matter (OM) turnover and thus alter both the processing of dissolved organic matter (DOM) in soils and presumably also the export of DOM to headwater streams, which intimately connect the terrestrial with the aquatic environment. Size....... By comparing six agriculturally and six forest-impacted headwater streams, we demonstrated that agriculture promotes increased DOC and DON concentrations, entailing an even more pronounced effect on DON. The major part of DOC and DON in agricultural and forest reference streams is exported in the form of humic....... Altogether, DOM in agricultural headwaters is mainly complex-soil-derived and aromatic material with a low C:N ratio, which is more microbial processed than its counterpart from forest reference catchments. Our results emphasize the importance of agricultural land use on DOM loss from soils and identify...

  16. Innovative process scheme for removal of organic matter, phosphorus and nitrogen from pig manure

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Schmidt, Jens Ejbye; Angelidaki, Irini

    2008-01-01

    Disposal of pig manure often requires treatment with respect to environmental legislations. In this study different processes for reduction of the organic matter (anaerobic digestion, effluent separation by decanter centrifugation, membrane microfiltration, post-digestion in upflow anaerobic sludge...

  17. "Ready to Acquire"

    DEFF Research Database (Denmark)

    Yetton, Philip; Henningsson, Stefan; Bjørn-Andersen, Niels

    2013-01-01

    This article describes the experiences of Danisco (a global food ingredients company) as it followed a growth-by-acquisition business strategy, focusing on how a new CIO built the IT resources to ensure the IT organization was "ready to acquire." We illustrate how these IT capabilities expedited...... the IT integration following two acquisitions, one of which involved Danisco expanding the scale of its business and the other extending the scope. Based on insights gained from Danisco, we provide lessons for CIOs to realize business benefits when managing post-acquisition IT integration....

  18. Ultrasound coupled with Fenton oxidation pre-treatment of sludge to release organic carbon, nitrogen and phosphorus

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Changxiu [School of Environment, Tsinghua University, Beijing 100084 (China); Jiang, Jianguo, E-mail: jianguoj@mail.tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China); Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China (China); Collaborative Innovation Center for Regional Environmental Quality, Tsinghua University, Beijing (China); Li, De' an [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-11-01

    We focused on the effects of ultrasound and Fenton reagent in ultrasonic coupling Fenton oxidation (U + F) pre-treatment processes on the disintegration of wastewater treatment plant sludge. The results demonstrated that U + F treatment could significantly increase soluble COD, TOC, total N, proteins, total P and PO{sub 4}{sup 3−} concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U + F treatment increased the soluble COD by 2.1- and 1.4-fold compared with U and F alone, respectively. U + F treatment increased the total N and P by 1.7- and 2.2-fold, respectively, compared with F alone. After U + F treatment, sludge showed a considerably finer particle size and looser microstructure based on scanning electron microscopy, and the highest OH· signal intensity increased from 568.7 by F treatment to 1106.3 using electron spin resonance. This demonstrated that U + F treatment induces disintegration of sludge and release of organic carbon, nitrogen and phosphorus better. - Highlights: • Combined ultrasound–Fenton pre-treatment was proposed for sludge disintegration. • Ultrasound–Fenton significantly increased carbon, nitrogen and phosphorus release. • Higher level of OH· was detected after combined disintegration than Fenton.

  19. Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

    Science.gov (United States)

    Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

    2017-02-01

    Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25–2 mm), and micro- (0.053–0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics.

  20. Intensified organics and nitrogen removal in the intermittent-aerated constructed wetland using a novel sludge-ceramsite as substrate.

    Science.gov (United States)

    Wu, Haiming; Fan, Jinlin; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Lv, Jialong; Lu, Shaoyong; Wu, Weizhong; Wu, Suqing

    2016-06-01

    In this study, a novel sludge-ceramsite was applied as main substrate in intermittent-aerated subsurface flow constructed wetlands (SSF CWs) for treating decentralized domestic wastewater, and intensified organics and nitrogen removal in different SSF CWs (with and without intermittent aeration, with and without sludge-ceramsite substrate) were evaluated. High removal of 97.2% COD, 98.9% NH4(+)-N and 85.8% TN were obtained simultaneously in the intermittent-aerated CW system using sludge-ceramsite substrate compared with non-aerated CWs. Moreover, results from fluorescence in situ hybridization (FISH) analysis revealed that the growth of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the intermittent-aerated CW system with sludge-ceramsite substrate was enhanced, thus indicating that the application of intermittent aeration and sludge-ceramsite plays an important role in nitrogen transformations. These results suggest that a combination of intermittent aeration and sludge-ceramsite substrate is reliable to enhance the treatment performance in SSF CWs.

  1. Volatile organic compounds released from Microcystis flos-aquae under nitrogen sources and their toxic effects on Chlorella vulgaris.

    Science.gov (United States)

    Xu, Qinghuan; Yang, Lin; Yang, Wangting; Bai, Yan; Hou, Ping; Zhao, Jingxian; Zhou, Lv; Zuo, Zhaojiang

    2017-01-01

    Eutrophication promotes massive growth of cyanobacteria and algal blooms, which can poison other algae and reduce biodiversity. To investigate the differences in multiple nitrogen (N) sources in eutrophicated water on the emission of volatile organic compounds (VOCs) from cyanobacteria, and their toxic effects on other algal growth, we analyzed VOCs emitted from Microcystis flos-aquae with different types and concentrations of nitrogen, and determined the effects under Normal-N and Non-N conditions on Chlorella vulgaris. M. flos-aquae released 27, 22, 20, 27, 19, 25 and 17 compounds, respectively, with NaNO3, NaNO2, NH4Cl, urea, Ser, Lys and Arg as the sole N source. With the reduction in N amount, the emission of VOCs was increased markedly, and the most VOCs were found under Non-N condition. C. vulgaris cell propagation, photosynthetic pigment and Fv/Fm declined significantly following exposure to M. flos-aquae VOCs under Non-N condition, but not under Normal-N condition. When C. vulgaris cells were treated with two terpenoids, eucalyptol and limonene, the inhibitory effects were enhanced with increasing concentrations. Therefore, multiple N sources in eutrophicated water induce different VOC emissions from cyanobacteria, and reduction in N can cause nutrient competition, which can result in emissions of more VOCs. Those VOCs released from M. flos-aquae cells under Non-N for nutrient competition can inhibit other algal growth. Among those VOCs, eucalyptol and limonene are the major toxic agents.

  2. Spectrophotometric determination of organic nitrogen by a modified Lassaigne method and its application to meat products and baby food.

    Science.gov (United States)

    Demirata, Birsen; Apak, Resat; Afsar, Hüseyin; Tor, Izzet

    2002-01-01

    A modified Lassaigne method was developed for N determination based on fusion of the organic substance with metallic Na, conversion of the cyanide in the aqueous leachate to thiocyanate by ammonium polysulfide treatment, and colorimetric measurement of the thiocyanate formed by the addition of excessive ferric ions in acidic medium. The mean molar absorptivity of the Fe(NCS)2+ complex at 480 nm is 2.96 x 10(3) L/mol x cm, enabling quantitation of 0.25-7.72 ppm N (linear range) in the final solution. The relative amounts of Na, (NH4)2S2, and Fe(III) with respect to nitrogen in the analyte were optimized. The developed method was successfully applied to the determination of N in various brands of baby food, and it was compared statistically with the conventional Kjeldahl and elemental analysis methods. Protein nitrogen in a number of meat products was also precisely determined by the developed method. Thus, the total digestion time of the conventional Kjeldahl method was reduced considerably (e.g., to approximately 15 min for a dried sample) with a relatively simple spectrophotometric method requiring no sophisticated instrumentation.

  3. Soil aggregate mediates the impacts of land uses on organic carbon, total nitrogen, and microbial activity in a Karst ecosystem

    Science.gov (United States)

    Xiao, Shuangshuang; Zhang, Wei; Ye, Yingying; Zhao, Jie; Wang, Kelin

    2017-01-01

    Understanding the effect of land use on soil carbon, nitrogen, and microbial activity associated with aggregates is critical for thorough comprehension of the C and N dynamics of karst landscapes/ecosystems. We monitored soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC), and Cmic: Corg ratio in large macro- (>2 mm), small macro- (0.25–2 mm), and micro- (0.053–0.25 mm) aggregates to determine the changes in soil properties under different land uses in the karst area of Southwest China. Five common land-use types—enclosure land (natural system, control), prescribed-burning land, fuel-wood shrubland, pasture and maize fields—were selected. Results showed that pasture and maize fields remarkably decreased the SOC and TN concentrations in aggregates. Conversion of natural system to other land uses decreased MBC (except for prescribed-burning) and increased Cmic: Corg ratios in aggregates. The extent of the response to land uses of SOC and TN concentrations was similar whereas that of MBC and Cmic: Corg ratios differed across the three aggregate sizes. Further, the SOC concentrations were significantly higher in macro-aggregates than micro-aggregates; the MBC and Cmic: Corg ratios were highest in small macro-aggregates. Therefore, small macro-aggregates might have more active C dynamics. PMID:28211507

  4. Distribution of inorganic and organic nutrients in the South Pacific Ocean – evidence for long-term accumulation of organic matter in nitrogen-depleted waters

    Directory of Open Access Journals (Sweden)

    F. Cerutti

    2007-08-01

    Full Text Available The BIOSOPE cruise of the RV Atalante was devoted to study the biogeochemical properties in the South Pacific between the Marquesas Islands (141° W–8° S and the Chilean upwelling (73° W–34° S. The 8000 km cruise had the opportunity to encounter different trophic situations, and especially strong oligotrophic conditions in the Central South Pacific Gyre (SPG, between 123° W and 101° W. In this isolated region, nitrate was undetectable between surface and 160–180 m, while regenerated nitrogen (nitrite and ammonium only revealed some traces (<20 nmoles l−1, even in the subsurface maximum. Integrated nitrate over the photic layer, which reached 165 m, was close to zero. In spite of this severe nitrogen-depletion, phosphate was always present at significant concentrations (≈0.1 μmoles l−1, while silicate maintained at low but classical oceanic levels (≈1 μmoles l−1. In contrast, the Marquesas region (MAR at west and Chilean upwelling (UPW at east were characterized by large nutrient contents one hundred to one thousand fold higher than in the SPG. Distribution of surface chlorophyll concentration reflected this gradient of nitrate availability. The lowest value (0.023 nmoles l−1 was measured in the centre of the SPG, where integrated chlorophyll over the photic layer was very weak (≈10 mg m−2, since a great part (up to 50% of the deep chlorophyll maximum (DCM was located below the 1% light. But, because of the relative high concentration encountered in the DCM (0.2 μg l−1, chlorophyll a content over the photic layer varied much less (by a factor 2 to 5 than the nitrate content. In contrast to chlorophyll a, integrated content of particulate organic matter (POM remained more or less constant along the investigated area (500 mmoles m−2, 60 mmoles m−2 and 3.5 mmoles m−2 for particulate organic carbon, particulate organic nitrogen and particulate organic phosphorus, respectively, except in the upwelling where values

  5. A review on nitrogen and organics removal mechanisms in subsurface flow constructed wetlands: dependency on environmental parameters, operating conditions and supporting media.

    Science.gov (United States)

    Saeed, Tanveer; Sun, Guangzhi

    2012-12-15

    With the unique advantages of lower operational and maintenance cost, the applications of subsurface flow constructed wetlands for the treatment of wastewater have been increasing rapidly throughout the world. The removal of nitrogen and organics by such systems has gained substantial attention in recent years. In subsurface flow wetlands, the removal of pollutants often relies on a diverse range of co-existing physical, chemical and biological routes, which are vitally dependent on numerous environmental and operational parameters. This paper provides a comprehensive review of wetland structures, classic and novel nitrogen and organics removal mechanisms along with the key environmental parameters and operational conditions that enhance removal in subsurface flow wetland systems. The critical exploration identifies the major environmental parameters such as: pH, DO, and temperature, operational factors i.e. organic carbon availability, loading, feed mode, retention time, recirculation, harvesting, and the complex role (of both parameters) on classical nitrogen and organics removal pathways. Subsequently, the necessity of further extensive research on such factors, for promoting novel nitrogen removal routes in wetland systems has also been highlighted. The expansion of the review on the influence of the unconventional wetland matrix indicates that, the structural differences and inherent properties of these media can support substantial nitrogen and organics removal from wastewater, under optimal operating conditions. Overall, the critical review illustrates the necessity of a profound knowledge on the complicated inter-relationship between nitrogen and organics removal routes, governing environmental and operational parameters, and wetland matrix for improving the treatment performances of subsurface flow wetlands.

  6. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    Science.gov (United States)

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future.

  7. Sources and fate of organic carbon and nitrogen from land to ocean: Identified by coupling stable isotopes with C/N ratio

    Science.gov (United States)

    Li, Yuan; Zhang, Haibo; Tu, Chen; Fu, Chuancheng; Xue, Yong; Luo, Yongming

    2016-11-01

    The transport of organic matter in coastal areas plays an important role in global biogeochemical cycles. The present study used stable isotopes including carbon (δ13C) and nitrogen (δ15N) and C/N ratio to assess the sources and fate of organic carbon and nitrogen in soils and sediments of a coastal plain-river plume-bay system. Changes of the δ13C and δ15N values from natural to agricultural soils in the Yellow River coastal plain reflected the contribution of C4 carbon, decomposition of organic matter and application of nitrogen fertilizer. The organic carbon in the marine sediments adjacent to the coastal plain mainly originated from C3-dominated terrestrial systems. The spatial heterogeneity of both δ13C and δ15N values indicated that Yellow River sediment transport and anthropogenic wastewater discharge were two driving forces for the sedimentary organic carbon and nitrogen dynamics in large river plume and inner bay areas. Meanwhile, the marine primary production and denitrification process as affected by excessive nutrient input also contributed to the cycling of organic matter. Wetland soils, cropland soils, vegetable soils, coastal and deep-sea sediments were the five systems controlling the cycle of organic carbon and nitrogen in the study area. A significant positive correlation between δ13C and δ15N in the Yellow River coastal plain-plume-bay region was observed, which implied the flux of organic matter from a labile pool in source regions into a more recalcitrant pool in sink regions. These findings would provide a better understanding of carbon sequestration in the coastal soil and sediment.

  8. The influence of dissolved organic matter (DOM) on sodium regulation and nitrogenous waste excretion in the zebrafish (Danio rerio).

    Science.gov (United States)

    Al-Reasi, Hassan A; Smith, Scott D; Wood, Chris M

    2016-08-01

    Dissolved organic matter (DOM) is both ubiquitous and diverse in composition in natural waters, but its effects on the branchial physiology of aquatic organisms have received little attention relative to other variables (e.g. pH, hardness, salinity, alkalinity). Here, we investigated the effects of four chemically distinct DOM isolates (three natural, one commercial, ranging from autochthonous to highly allochthonous, all at ∼6 mg C l(-1)) on the physiology of gill ionoregulation and nitrogenous waste excretion in zebrafish acclimated to either circumneutral (7.0-8.0) or acidic pH (5.0). Overall, lower pH tended to increase net branchial ammonia excretion, net K(+) loss and [(3)H]PEG-4000 clearance rates (indicators of transcellular and paracellular permeability, respectively). However, unidirectional Na(+) efflux, urea excretion and drinking rates were unaffected. DOM sources tended to stimulate unidirectional Na(+) influx rate and exerted subtle effects on the concentration-dependent kinetics of Na(+) uptake, increasing maximum transport capacity. All DOM sources reduced passive Na(+) efflux rates regardless of pH, but exerted negligible effects on nitrogenous waste excretion, drinking rate, net K(+) loss or [(3)H]PEG-4000 clearance, so the mechanism of Na(+) loss reduction remains unclear. Overall, these actions appear beneficial to ionoregulatory homeostasis in zebrafish, and some may be related to physico-chemical properties of the DOM sources. They are very different from those seen in a recent parallel study on Daphnia magna using the same DOM isolates, indicating that DOM actions may be both species and DOM specific.

  9. Nitrogen stable isotope ratios of anthropgenic organic matter in the coastal environment of Kosirina Bay (Murter Island, Croatia)

    Science.gov (United States)

    Dolenec, T.; Lambaša, Ž.; Lojen, S.; Rogan, N.; Kniewald, G.; Dolenec, M.

    2009-04-01

    In this study stable nitrogen isotopes ratios of particulate matter POM, zooplankton and selected biota such as Anemonia sulcata and Mytilus galloprovincialis were used to assessed the impact of anthropogenically derived organic matter from the untreated domestic sewage, municipal and industrial effluents on the coastal ecosystem of the Kosirina Bay (Murter Island). The differences in δ15N values observed in POM and organisms collected in Kosirina Bay as compared to POM and biota sampled at unaffected sites from the southern part of the Kornati Island and highly impacted Pirovac Bay revealed only a very minor effects of anthropogenic inputs of nutrients and organic matter which most probably derived from a sewage outfall south of the Tužbina Island. However, to get a better insight into the qualitative or quantitative shifts in the structure of aquatic food web caused by pollutants, more extended research on benthic population is needed, as well as a detailed investigation of seasonal variations of abundance and isotopic composition of POM and zooplankton as their presumed food source.

  10. Effect of Long-Term Fertilization on Organic Nitrogen Forms in a Calcareous Alluvial Soil on the North China Plain

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to illustrate the change of nitrogen (N) supply capacity after long-term application of manure and chemical fertilizer, as well as to properly manage soil fertility through fertilizer application under the soil-climatic conditions of the North China Plain, organic N forms were quantified in the topsoil with different manure and chemical fertilizer treatments in a 15-year fertilizer experiment in a Chinese calcareous alluvial soil Soil total N (TN) and various organic N forms were significantly influenced by long-term application of chemical fertilizer and manure. TN, total hydrolysable N, acid-insoluble N, amino acid N and ammonium N in the soil increased significantly (P < 0.05) with increasing manure and fertilizer N rates, but were not influenced by increasing P rates. Also, application of manure or N fertilizer or P fertilizer did not significantly influence either the quantity of amino sugar N or its proportion of TN. Application of manure significantly increased (P < 0.05) hydrolysable unknown N, but adding N or P did not. In addition, application of manure or N fertilizer or P fertilizer did not significantly influence the proportions of different soil organic N forms.

  11. Effect of Continuous Agriculture of Grassland Soils of the Argentine Rolling Pampa on Soil Organic Carbon and Nitrogen

    Directory of Open Access Journals (Sweden)

    Luis A. Milesi Delaye

    2013-01-01

    Full Text Available Long-term soil organic carbon (SOC and soil organic nitrogen (SON following cultivation of grassland soils (100/120-year tillage (T + 20/30-year no tillage (NT of the Rolling Pampa were studied calibrating the simple AMG model coupled with the natural 13C abundance measurements issued from long-term experiments and validating it on a data set obtained by a farmer survey and by long-term NT experiments. The multisite survey and NT trials permitted coverage of the history of the 140 years with agriculture. The decrease in SOC and SON storage that occurred during the first twenty years by a loss through biological activity was 27% for SOC and 32% for SON. The calibrated model described the SOC storage evolution very well and permitted an accurate simultaneous estimation of their three parameters. The validated model simulated well SOC and SON evolution. Overall, the results analyzed separately for the T and NT period indicated that the active pool has a rapid turnover (MRT ~9 and 13 years, resp. which represents 50% of SOC in the native prairie soil and 20% of SOC at equilibrium after NT period. NT implementation on soils with the highest soil organic matter reserves will continue to decrease (17% for three decades later under current annual addition.

  12. Inorganic nitrogen leaching from organic and conventional rice production on a newly claimed calciustoll in Central Asia.

    Science.gov (United States)

    Meng, Fanqiao; Olesen, Jørgen E; Sun, Xiangping; Wu, Wenliang

    2014-01-01

    Characterizing the dynamics of nitrogen (N) leaching from organic and conventional paddy fields is necessary to optimize fertilization and to evaluate the impact of these contrasting farming systems on water bodies. We assessed N leaching in organic versus conventional rice production systems of the Ili River Valley, a representative aquatic ecosystem of Central Asia. The N leaching and overall performance of these systems were measured during 2009, using a randomized block experiment with five treatments. PVC pipes were installed at soil depths of 50 and 180 cm to collect percolation water from flooded organic and conventional paddies, and inorganic N (NH4-N+NO3-N) was analyzed. Two high-concentration peaks of NH4-N were observed in all treatments: one during early tillering and a second during flowering. A third peak at the mid-tillering stage was observed only under conventional fertilization. NO3-N concentrations were highest at transplant and then declined until harvest. At the 50 cm soil depth, NO3-N concentration was 21-42% higher than NH4-N in percolation water from organic paddies, while NH4-N and NO3-N concentrations were similar for the conventional and control treatments. At the depth of 180 cm, NH4-N and NO3-N were the predominant inorganic N for organic and conventional paddies, respectively. Inorganic N concentrations decreased with soil depth, but this attenuation was more marked in organic than in conventional paddies. Conventional paddies leached a higher percentage of applied N (0.78%) than did organic treatments (0.32-0.60%), but the two farming systems leached a similar amount of inorganic N per unit yield (0.21-0.34 kg N Mg(-1) rice grains). Conventional production showed higher N utilization efficiency compared to fertilized organic treatments. These results suggest that organic rice production in the Ili River Valley is unlikely to reduce inorganic N leaching, if high crop yields similar to conventional rice production are to be maintained.

  13. Response of organic and inorganic carbon and nitrogen to long-term grazing of the shortgrass steppe.

    Science.gov (United States)

    Reeder, Jean D; Schuman, Gerald E; Morgan, Jack A; Lecain, Daniel R

    2004-04-01

    We investigated the influence of long-term (56 years) grazing on organic and inorganic carbon (C) and nitrogen (N) contents of the plant-soil system (to 90 cm depth) in shortgrass steppe of northeastern Colorado. Grazing treatments included continuous season-long (May-October) grazing by yearling heifers at heavy (60-75% utilization) and light (20-35% utilization) stocking rates, and nongrazed exclosures. The heavy stocking rate resulted in a plant community that was dominated (75% of biomass production) by the C4 grass blue grama (Bouteloua gracilis), whereas excluding livestock grazing increased the production of C3 grasses and prickly pear cactus (Opuntia polycantha). Soil organic C (SOC) and organic N were not significantly different between the light grazing and nongrazed treatments, whereas the heavy grazing treatment was 7.5 Mg ha(-1) higher in SOC than the nongrazed treatment. Lower ratios of net mineralized N to total organic N in both grazed compared to nongrazed treatments suggest that long-term grazing decreased the readily mineralizable fraction of soil organic matter. Heavy grazing affected soil inorganic C (SIC) more than the SOC. The heavy grazing treatment was 23.8 Mg ha(-1) higher in total soil C (0-90 cm) than the nongrazed treatment, with 68% (16.3 Mg ha(-1)) attributable to higher SIC, and 32% (7.5 Mg ha(-1)) to higher SOC. These results emphasize the importance in semiarid and arid ecosystems of including inorganic C in assessments of the mass and distribution of plant-soil C and in evaluations of the impacts of grazing management on C sequestration.

  14. Acquired platelet function defect

    Science.gov (United States)

    Acquired qualitative platelet disorders; Acquired disorders of platelet function ... blood clotting. Disorders that can cause problems in platelet function include: Idiopathic thrombocytopenic purpura Chronic myelogenous leukemia Multiple ...

  15. Yield and growth components of potato and wheat under organic nitrogen management

    NARCIS (Netherlands)

    Delden, van A.

    2001-01-01

    In order to optimize N management in organic farming systems, knowledge of crop growth processes in relation to N limitation is necessary. The present paper examines the response of potato (Solanum tuberosum L.) and wheat (Triticum aestivum L.) to N with respect to intercepted photosynthetically act

  16. Influence of reduced tillage and fertilization regime on crop performance and nitrogen utilization of organic potato

    NARCIS (Netherlands)

    Drakopoulos, Dimitrios; Scholberg, J.M.S.; Lantinga, E.A.; Tittonell, P.A.

    2016-01-01

    The majority of Dutch farmers perceive that mouldboard ploughing prior to potato planting is necessary, despite its negative impacts on inherent soil fertility and soil structure. An innovative agronomic practice in Dutch organic agriculture is the use of cut-and-carry fertilizers with which above-g

  17. The Effects of Three Mineral Nitrogen Sources and Zinc on Maize and Wheat Straw Decomposition and Soil Organic Carbon

    Institute of Scientific and Technical Information of China (English)

    Ogunniyi Jumoke Esther; GUO Chun-hui; TIAN Xiao-hong; LI Hong-yun; ZHOU Yang-xue

    2014-01-01

    The incorporation of straw in cultivated ifelds can potentially improve soil quality and crop yield. However, the presence of recalcitrant carbon compounds in straw slow its decomposition rate. The objective of this study was to determine the effects of different nitrogen sources, with and without the application of zinc, on straw decomposition and soil quality. Soils were treated with three different nitrogen sources, with and without zinc: urea (CO(NH2)2), ammonium sulfate ((NH4)2SO4), and ammonium chloride (NH4Cl). The combined treatments were as follows:maize (M) and wheat (W) straw incorporated into urea-, ammonium sulfate-, or ammonium chloride-treated soil (U, S, and C, respectively) with and without zinc (Z) (MU, MUZ, WU, WUZ;MS, MSZ, WS, WSZ;MC, MCZ, WC, WCZ, respectively);straw with zinc only (MZ, WZ);straw with untreated soil (MS, WS);and soil-only or control conditions (NT). The experiment consisted of 17 treatments with four replications. Each pot contained 150 g soil and 1.125 g straw, had a moisture content of 80%of the ifeld capacity, and was incubated for 53 days at 25°C. The rates of CO2-C emission, cumulative CO2-C evolution, total CO2 production in the soils of different treatments were measured to infer decomposition rates. The total organic carbon (TOC), labile organic carbon (LOC), and soil microbial biomass in the soils of different treatments were measured to infer soil quality. All results were signiifcantly different (P<0.05) with the exception of the labile organic carbon (LOC). The maize and wheat straw showed different patterns in CO2 evolution rates. For both straw types, Zn had a synergic effect with U, but an antagonistic effect with the other N sources as determined by the total CO2 produced. The MUZ treatment showed the highest decomposition rate and cumulative CO2 concentration (1 120.29 mg/pot), whereas the WACZ treatment had the lowest cumulative CO2 concentration (1 040.57 mg/pot). The addition of NH4Cl resulted in the

  18. C2H2 adsorption in three isostructural metal-organic frameworks: boosting C2H2 uptake by rational arrangement of nitrogen sites.

    Science.gov (United States)

    Song, Chengling; Jiao, Jingjing; Lin, Qiyi; Liu, Huimin; He, Yabing

    2016-03-21

    Replacing the benzene spacer in the organic linker 5,5'-(benzene-1,4-diyl)diisophthalate with the nitrogen containing heterocyclic rings, namely, pyrazine, pyridazine, and pyrimidine results in three organic linkers, which were reacted with copper ions under solvothermal conditions to form three isostructural metal-organic frameworks (ZJNU-46, ZJNU-47 and ZJNU-48) exhibiting exceptionally high sorption capacities with regard to acetylene due to the simultaneous immobilization of open metal sites and Lewis basic nitrogen sites in the frameworks. At 1 atm and 295 K, the gravimetric C2H2 adsorption uptakes reach 187, 213 and 193 cm(3) (STP) g(-1) for these three compounds. The gravimetric C2H2 adsorption amount of ZJNU-47a is the second highest reported for MOF materials. Notably, despite their same porosities, and densities of open metal sites and uncoordinated nitrogen sites, distinctly different C2H2 adsorption capacities were observed for these three compounds, which we think are mainly associated with the difference in the relative position of nitrogen atoms leading to different binding affinities of the frameworks towards C2H2 guest molecules, and thus different C2H2 adsorptions. This work demonstrates that the rational arrangement of open nitrogen sites will favorably improve the C2H2 uptake and thus provides useful information for future design of porous MOFs with high acetylene storage capacities.

  19. Organic geochemical evidence for nitrogen-limited oligotrophic seas in the Late Ordovician

    Science.gov (United States)

    Rohrssen, M.; Love, G. D.

    2011-12-01

    The Late Ordovician (~450-44 Ma) was a period of drastic environmental change, beginning in a hothouse climate with epeiric seaways near a Phanerozoic high and concluding with the Hirnantian glaciation, large positive carbon isotope excursion(s) (Hirnantian isotopic carbon excursion, HICE) and one of the Big Five mass extinctions. Warm sea temperatures and low oxidant concentrations relative to modern likely made intervals of the Late Ordovician particularly suited to the development of extensive denitrification in oxygen minimum zones (OMZs), contributing to nitrogen limitation of marine ecosystems. Mixed carbonate/siliciclastic deposits on Anticosti Island, Canada, provide an excellent opportunity to assemble stratigraphic lipid biomarker records of microbial community structure and response to environmental change associated with the Hirnantian glaciation in a tropical epeiric seaway. Lipid biomarkers extracted from Anticosti rocks yield low thermal maturities, consistent with the shallow burial history of the island and lack molecules likely derived from contamination (e.g. zero oleanane from angiosperms). In addition, Anticosti bitumens bear the C29 sterane predominance and low C28/C29 sterane ratio expected from Lower Paleozoic rocks. Anticosti biomarkers reveal unusual environmenal conditions throughout the Hirnantian at Anticosti. Despite the presence of unequivocally marine fossils, Anticosti bitumens contain no detectable 24-n-propylcholestane, usually a robust marker of marine environmental conditions. Anticosti bitumen have high abundances of 3β-methylhopanes (4-11% of C30 αβ-hopane), molecules which are commonly associated with Type I methanotrophic bacteria. Moderate abundances of 2α-methylhopane (2-4% C30 αβ-hopane) with only trace quantities of gammacerane are found. Hopane/sterane ratios, reflecting a highercontribution of bacteria relative to eukaryotes, range from 1.8 to 11.2 (average 4.8), higher than the Phanerozoic marine average of 0

  20. Chemistry of fog waters in California's Central Valley - Pt. 3: concentrations and speciation of organic and inorganic nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Qi Zhang; Anastasio, C. [University of California, Davis, CA (United States). Atmospheric Science Program, Department of Land, Air and Water Resources

    2001-07-01

    Although organic nitrogen (ON) has been found to be a ubiquitous and significant component in wet and dry deposition, almost nothing is known about its concentration or composition in fog waters. To address this gap, we have investigated the concentration and composition of ON in fog waters collected in Davis, in California's Central Valley. Significant quantities of dissolved organic nitrogen (DON) were found in these samples, with a median concentration of 303{mu}M N (range=120-1630{mu}M N). DON typically represented approximately 16% of the total dissolved nitrogen (inorganic+organic) in Davis fog waters. The median concentration of nitrogen in free amino acids and alkyl amines was 16{mu}M N (range=3.8-120{mu}M N), which accounted for 3.4% of the DON in Davis fogs. Thus, although the absolute concentrations of free amino compounds were significant, they were only a minor component of the DON pool. Combined amino nitrogen (e.g., proteins and peptides) was present at higher concentrations and accounted for 6.1-29 per cent (median=16%) of DON. Overall, free and combined amino compounds typically accounted for a median value of 22% of DON in the fog waters. The high concentrations of DON found, and the fact that amino and other N-containing organic compounds can serve as nitrogen sources for microorganisms and plants, indicate that atmospheric ON compounds likely play an important role in nitrogen cycling in the Central Valley. In addition, due to the basicity of some N functional groups, ON compounds likely contribute to the previously observed acid buffering capacity of Central Valley fog waters. Finally, a comparison of fog waters with fine particles (PM{sub 2.5}) collected from the same site during the same period of time indicated that the median concentrations (mol Nm{sup -3}-air) of total water-soluble ON, free amino nitrogen and total amino nitrogen were very similar in the fog water and PM{sub 2.5}. Given the high water solubility of many organic N

  1. Molybdenum limitation of asymbiotic nitrogen fixation in tropical forest soils

    Science.gov (United States)

    Barron, Alexander R.; Wurzburger, Nina; Bellenger, Jean Phillipe; Wright, S. Joseph; Kraepiel, Anne M. L.; Hedin, Lars O.

    2009-01-01

    Nitrogen fixation, the biological conversion of di-nitrogen to plant-available ammonium, is the primary natural input of nitrogen to ecosystems, and influences plant growth and carbon exchange at local to global scales. The role of this process in tropical forests is of particular concern, as these ecosystems harbour abundant nitrogen-fixing organisms and represent one third of terrestrial primary production. Here we show that the micronutrient molybdenum, a cofactor in the nitrogen-fixing enzyme nitrogenase, limits nitrogen fixation by free-living heterotrophic bacteria in soils of lowland Panamanian forests. We measured the fixation response to long-term nutrient manipulations in intact forests, and to short-term manipulations in soil microcosms. Nitrogen fixation increased sharply in treatments of molybdenum alone, in micronutrient treatments that included molybdenum by design and in treatments with commercial phosphorus fertilizer, in which molybdenum was a `hidden' contaminant. Fixation did not respond to additions of phosphorus that were not contaminated by molybdenum. Our findings show that molybdenum alone can limit asymbiotic nitrogen fixation in tropical forests and raise new questions about the role of molybdenum and phosphorus in the tropical nitrogen cycle. We suggest that molybdenum limitation may be common in highly weathered acidic soils, and may constrain the ability of some forests to acquire new nitrogen in response to CO2 fertilization.

  2. Nitrogen Mineralization from Animal Manures and Its Relation to Organic N Fractions

    Institute of Scientific and Technical Information of China (English)

    LI Ling-ling; LI Shu-tian

    2014-01-01

    Laboratory aerobic incubation was conducted for 161 d to study N mineralization and the changes of organic N fractions of nine different manures (3 chicken manures, 3 pig manures and 3 cattle manures) from different farms/locations. Results indicated that signiifcant (P<0.01 orP<0.001) difference existed in N mineralization between manures. The rapid N mineralization in manures occurred during 56 to 84 d of incubation. First order exponential model can be used to describe N mineralization from chicken manures and pig manures, while quadratic equation can predict mineralization of organic N from cattle manures. An average of 21, 19 and 13% added organic N from chicken manure, pig manure and cattle manure was mineralized during 161 d of incubation. Amino acid-N was the main source of N mineralization. The changes of amino acid-N together with ammonium N could explain signiifcantly 97 and 96% of the variation in mineralized N from manured soils and manures. Amino acid-N and ammonium N are two main N fractions in determining N mineralization potential from manures. Amino acid-N contributed more to the mineralized N than ammonium N.

  3. Compost impacts on dissolved organic carbon and available nitrogen and phosphorus in turfgrass soil.

    Science.gov (United States)

    Wright, Alan L; Provin, Tony L; Hons, Frank M; Zuberer, David A; White, Richard H

    2008-01-01

    Compost application to turfgrass soils may increase dissolved organic C (DOC) levels which affects nutrient dynamics in soil. The objectives of this study were to investigate the influence of compost source and application rate on soil organic C (SOC), DOC, NO(3), and available P during 29 months after a one-time application to St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] turf. Compost sources had variable composition, yet resulted in few differences in SOC, DOC, and NO(3) after applied to soil. Available NO(3) rapidly decreased after compost application and was unaffected by compost source and application rate. Available P increased after compost application and exhibited cyclical seasonal patterns related to DOC. Compost application decreased soil pH relative to unamended soil, but pH increased during the course of the study due to irrigation with sodic water. Increasing the compost application rate increased SOC by 3 months, and levels remained fairly stable to 29 months. In contrast, DOC continued to increase from 3 to 29 months after application, suggesting that compost mineralization and growth of St. Augustinegrass contributed to seasonal dynamics. Dissolved organic C was 75%, 78%, and 101% greater 29 months after application of 0, 80, and 160 Mg compostha(-1), respectively, than before application. Impacts of composts on soil properties indicated that most significant effects occurred within a few months of application. Seasonal variability of SOC, DOC, and available P was likely related to St. Augustinegrass growth stages as well as precipitation, as declines occurred after precipitation events.

  4. Diversity and activity of free-living nitrogen-fixing bacteria and total bacteria in organic and conventionally managed soils.

    Science.gov (United States)

    Orr, Caroline H; James, Angela; Leifert, Carlo; Cooper, Julia M; Cummings, Stephen P

    2011-02-01

    Agricultural soils are heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, the molecular ecology of the total bacterial and free-living nitrogen-fixing communities in soils from the Nafferton Factorial Systems Comparison (NFSC) study in northeast England were examined. The field experiment was factorial in design, with organic versus conventional crop rotation, crop protection, and fertility management factors. Soils were sampled on three dates (March, June, and September) in 2007. Total RNA was extracted from all soil samples and reverse transcribed. Denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) were used to analyze nifH and 16S rRNA genes in order to study free-living diazotrophs and the total bacterial community, respectively. Crop rotation was shown to have a significant effect on total bacterial diversity (and that of free-living N fixers) (P ≤ 0.001). On all three dates, nifH activity was higher in the conventional crop rotation. In contrast, qPCR analysis of free-living N fixers indicated significantly higher levels of activity in conventionally fertilized plots in June (P = 0.0324) and in plots with organic crop protection in September (P = 0.0143). To our knowledge, the effects of organic and conventional farming systems on free-living diazotrophs have never been studied. An increased understanding of the impacts of management practices on free-living N fixers could allow modifications in soil management practices to optimize the activity of these organisms.

  5. Abundance and diversity of total and nitrifying prokaryotes as influenced by biochemical quality of organic inputs combined with mineral nitrogen

    Science.gov (United States)

    Muema, Esther; Vanlauwe, Bernard; Röhl, Carolin; Cadisch, Georg; Rasche, Frank

    2014-05-01

    Ammonia-oxidizing bacteria and archaea (AOB, AOA) co-exist in soil, but they respond differently to distinct fertilization strategies in agricultural soils. Accordingly, effects of organic inputs and combination with mineral nitrogen (N) on AOB and AOA remain poorly understood. The aim of this study was to compare soil amendment with contrasting quality of organic inputs (i.e., high quality Tithonia diversifolia (TD; C/N ratio: 13, Lignin: 8.9 %; Polyphenols: 1.7 %), intermediate quality Calliandra calothyrsus (CC; 13; 13; 9.4) and low quality Zea mays (ZM; 59; 5.4; 1.2)), and combination with mineral N on the abundance (i.e., DNA-based gene quantification) and community structure (i.e., T-RFLP analysis) of total bacterial and archaea (16S rRNA gene), as well as AOB and AOA (targeting the amoA gene) communities in a Humic Nitisol. Soils (0-15 cm depth) were sampled prior to the onset of the rainy season in March 2012 in a 10 years old field experiment established in the central highlands of Kenya in 2002. Since the start of the experiment, organic inputs were applied annually at a rate of 4 Mg C ha-1 and mineral N twice a year as calcium ammonium nitrate (5Ca(NO3)2NH4NO3) at a rate of 120 kg N ha-1 growing season-1. Quality of organic inputs posed only a significant effect on the AOB community structure between TD versus ZM and CC versus ZM. Moreover, TD significantly increased the size of AOB over ZM input, while higher abundances for total bacteria, total archaea and AOA were measured in ZM and TD over CC. This was explained by high and available N in TD, but low lignin and polyphenol contents in TD and ZM as opposed to CC. AOB responded sensitively (i.e., complete community structure separation) to mineral N, specifically when combined with low quality ZM. Hence, AOB community was specifically responsive to quality of organic inputs and combination of low organic input with mineral N over AOA and total prokaryotic communities in the studied soil. The results

  6. Two years of gaseous emissions from contrasting soils amended with organic and synthetic nitrogen fertilizers.

    Science.gov (United States)

    Pelster, D. E.; Chantigny, M. H.; Rochette, P.; Angers, D. A.; Rieux, C.; Vanasse, A.

    2012-04-01

    Animal manures are often used as a source of nitrogen (N) for agriculture; however impacts of amendment type on N2O production may vary. In this study, N2O emissions from two soil types with contrasting texture and carbon (C) content (a silty clay mixed frigid dystric eutrudept and a sandy loam mixed frigid typic dystrudept) were measured for two years under a cool, humid climate. Treatments consisted of a no N control (CTL), calcium ammonium nitrate (CAN), poultry manure (PM), liquid cattle manure (LCM), or liquid swine manure (LSM). The N sources were surface applied and immediately incorporated at 90 kg N ha-1 before seeding of spring wheat (Triticum aestivum L.). Leaching losses of N were also measured using zero-tension lysimeters located at approximately 0.35 m depth. Cumulative growing season N2O-N emissions from the silty clay ranged from 2.2 to 8.3 kg ha-1 yr-1 and were slightly lower in CTL plots than in the fertilized plots (P = 0.067). The mean N2O emission factors ranged from 2.0 to 4.4% of added N with no difference among treatments. Emissions of N2O from the sandy loam soil ranged from 0.3 to 2.2 kg N2O-N ha-1 yr-1, with greatest emissions following PM application (P < 0.001). The N2O emission factor from sandy loam plots amended with PM was 1.7%, more than double that of the other treatments (0.3 to 0.9%), likely because of the high C content of the PM. On the silty clay the yield-based N2O emissions (g N2O-N kg-1 grain yield N) were similar between treatments; while on the sandy loam, they were greatest when amended with PM. Annual N leaching losses averaged 28.7 kg ha-1 for the silty clay and 19.6 kg ha-1 for the sandy loam and were similar for all amendment types suggesting that off-site N2O emissions will also be similar amongst treatments. Preliminary data indicate that overwinter N2O emissions from sandy loam plots were consistently greater when amended with pig slurry compared with unamended soils, and that these overwinter losses may exceed

  7. Hierarchically porous silicon-carbon-nitrogen hybrid materials towards highly efficient and selective adsorption of organic dyes.

    Science.gov (United States)

    Meng, Lala; Zhang, Xiaofei; Tang, Yusheng; Su, Kehe; Kong, Jie

    2015-01-21

    The hierarchically macro/micro-porous silicon-carbon-nitrogen (Si-C-N) hybrid material was presented with novel functionalities of totally selective and highly efficient adsorption for organic dyes. The hybrid material was conveniently generated by the pyrolysis of commercial polysilazane precursors using polydivinylbenzene microspheres as sacrificial templates. Owing to the Van der Waals force between sp-hybridized carbon domains and triphenyl structure of dyes, and electrostatic interaction between dyes and Si-C-N matrix, it exhibites high adsorption capacity and good regeneration and recycling ability for the dyes with triphenyl structure, such as methyl blue (MB), acid fuchsin (AF), basic fuchsin and malachite green. The adsorption process is determined by both surface adsorption and intraparticle diffusion. According to the Langmuir model, the adsorption capacity is 1327.7 mg·g(-1) and 1084.5 mg·g(-1) for MB and AF, respectively, which is much higher than that of many other adsorbents. On the contrary, the hybrid materials do not adsorb the dyes with azo benzene structures, such as methyl orange, methyl red and congro red. Thus, the hierarchically porous Si-C-N hybrid material from a facile and low cost polymer-derived strategy provides a new perspective and possesses a significant potential in the treatment of wastewater with complex organic pollutants.

  8. Biodegradability and Molecular Composition of Dissolved Organic Nitrogen in Urban Stormwater Runoff and Outflow Water from a Stormwater Retention Pond.

    Science.gov (United States)

    Lusk, Mary G; Toor, Gurpal S

    2016-04-01

    Dissolved organic nitrogen (DON) can be a significant part of the reactive N in aquatic ecosystems and can accelerate eutrophication and harmful algal blooms. A bioassay method was coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to determine the biodegradability and molecular composition of DON in the urban stormwater runoff and outflow water from an urban stormwater retention pond. The biodegradability of DON increased from 10% in the stormwater runoff to 40% in the pond outflow water and DON was less aromatic and had lower overall molecular weight in the pond outflow water than in the stormwater runoff. More than 1227 N-bearing organic formulas were identified with FT-ICR-MS in the stormwater runoff and pond outflow water, which were only 13% different in runoff and outflow water. These molecular formulas represented a wide range of biomolecules such as lipids, proteins, amino sugars, lignins, and tannins in DON from runoff and pond outflow water. This work implies that the urban infrastructure (i.e., stormwater retention ponds) has the potential to influence biogeochemical processes in downstream water bodies because retention ponds are often a junction between the natural and the built environment.

  9. Trees' role in nitrogen leaching after organic, mineral fertilization: a greenhouse experiment.

    Science.gov (United States)

    López-Díaz, M L; Rolo, V; Moreno, G

    2011-01-01

    New sustainable agriculture techniques are arising in response to the environmental problems caused by intensive agriculture, such as nitrate leaching and surface water eutrophication. Organic fertilization (e.g., with sewage sludge) and agroforestry could be used to reduce nutrient leaching. We assessed the efficiency of establishing trees and pasture species in environmentally sensitive, irrigated Mediterranean grassland soils in controlling nitrate leaching. Four vegetation systems-bare soil, pasture species, cherry trees [ (L.) L.], and pasture-tree mixed plantings-and five fertilization treatments-control, two doses of mineral fertilizer, and two doses of organic fertilizer (sewage sludge)-were tested in a greenhouse experiment over 2 yr. In the experiment, the wet and warm climate characteristics of Mediterranean irrigated croplands and the plant-to-plant and soil-to-plant interactions that occur in open-field agroforestry plantations were simulated. Following a factorial design with six replicates, 120 pots (30-cm radius and 120 cm deep) were filled with a sandy, alluvial soil common in the cultivated fluvial plains of the region. The greatest pasture production and tree growth were obtained with sewage sludge application. Both pasture production and tree growth decreased significantly in the pasture-tree mixed planting. Nitrate leaching was negligible in this latter treatment, except under the highest dose of sewage sludge application. The rapid mineralization of sludge suggested that this organic fertilizer should be used very cautiously in warm, irrigated Mediterranean soils. Mixed planting of pasture species and trees, such as , could be a useful tool for mitigating nitrate leaching from irrigated Mediterranean pastures on sandy soils.

  10. Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia

    Science.gov (United States)

    Wild, Birgit; Schnecker, Jörg; Knoltsch, Anna; Takriti, Mounir; Mooshammer, Maria; Gentsch, Norman; Mikutta, Robert; Alves, Ricardo J. Eloy; Gittel, Antje; Lashchinskiy, Nikolay; Richter, Andreas

    2015-05-01

    Soil N availability is constrained by the breakdown of N-containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrification. According to stoichiometric theory, N mineralization and nitrification are expected to increase in relation to protein depolymerization with decreasing N limitation, and thus from higher to lower latitudes and from topsoils to subsoils. To test these hypotheses, we compared gross rates of protein depolymerization, N mineralization and nitrification (determined using 15N pool dilution assays) in organic topsoil, mineral topsoil, and mineral subsoil of seven ecosystems along a latitudinal transect in western Siberia, from tundra (67°N) to steppe (54°N). The investigated ecosystems differed strongly in N transformation rates, with highest protein depolymerization and N mineralization rates in middle and southern taiga. All N transformation rates decreased with soil depth following the decrease in organic matter content. Related to protein depolymerization, N mineralization and nitrification were significantly higher in mineral than in organic horizons, supporting a decrease in microbial N limitation with depth. In contrast, we did not find indications for a decrease in microbial N limitation from arctic to temperate ecosystems along the transect. Our findings thus challenge the perception of ubiquitous N limitation at high latitudes, but suggest a transition from N to C limitation of microorganisms with soil depth, even in high-latitude systems such as tundra and boreal forest.

  11. Seasonally varying nitrogen isotope biogeochemistry of particulate organic matter in Lake Kinneret, Israel

    Digital Repository Service at National Institute of Oceanography (India)

    Hadas, O.; Altabet, M.A.; Agnihotri, R.

    typically takes place in late April and May after the spring bloom when microbial degradation of abundant organic matter (OM) first consumed available O 2 and then used NO 3 - as an oxidant (electron acceptor). For example between March and June 2004... consuming NH 4 + and producing NO 3 - . In winter 2004, the nitrification period was not as well sampled, but stable post-nitrification values for δ 15 NO 3 - were also observed in the epilimnion but were ~5‰ higher than in 2005. It should be noted...

  12. Seasonal variation of nitrogen oxides, ozone and biogenic volatile organic compound concentrations and fluxes at Norway spruce forest

    Science.gov (United States)

    Juran, Stanislav; Vecerova, Kristyna; Holisova, Petra; Zapletal, Milos; Pallozzi, Emanuele; Guidolotti, Gabriele; Calfapietra, Carlo; Vecera, Zbynek; Cudlin, Pavel; Urban, Otmar

    2015-04-01

    Dynamics of nitrogen oxides (NOx) and ozone concentration and their depositions were investigated on the Norway spruce forest at Bily Kriz experimental station at the Silesian Beskydy Mountains (north-eastern part of the Czech Republic). Both NOx and ozone concentration and fluxes were modelled for the whole season and covering thus different climate conditions. Data were recorded for three consecutive years and therefore deeper analyses were performed. During the summer 2014 BVOC field campaign was carried out using proton-transfer-reaction-time-of-flight-mass-spectrometry (PTR-TOF, Ionicon Analytik GmbH, Innsbruck, Austria) and volatile organic compound of biogenic origin (BVOC) were measured at the different levels of tree canopies. By the same time BVOC were trapped into the Tenax tubes (Markes International Ltd., UK) and put afterwards for thermal desorption (Markes Unity System 2, Markes International Ltd., UK) to GS-MS analysis (TSQ Quntum XLS triple Quadrupole, Thermo Scientific, USA). Thus data of different levels of canopies together with different spectra of monoterpenes were obtained. Interesting comparison of both methods will be shown. It was the first BVOC field campaign using PTR technique at any of the forest in the Czech Republic. Highest fluxes and concentrations were recorded around the noon hours, represented particularly by monoterpenes, especially α-pinen and limonene. Other BVOCs than monoterpenes were negligible. Variation of fluxes between different canopies levels was observed, highlighting difference in shaded and sun exposed leaves. Sun leaves emitted up to 2.4 nmol m-2 s-1 of monoterpenes, while shaded leaves emitted only up to 0.6 nmol m-2 s-1 when measured under standard conditions (irradiance 1000 µmol m-2 s-1; temperature 30°C). We discuss here the importance of the most common Norway spruce tree forests in the Czech Republic in bi-directional exchanges of important secondary pollutant such as ozone and nitrogen oxides, their

  13. [Distribution and enrichment characteristics of organic carbon and total nitrogen in mollisols under long-term fertilization].

    Science.gov (United States)

    Xu, Xiang-ru; Luo, Kun; Zhou, Bao-ku; Wang, Jing-kuan; Zhang, Wen-ju; Xu, Ming-gang

    2015-07-01

    The characteristics and changes of soil organic carbon (SOC) and total nitrogen (TN) in different size particles of soil under different agricultural practices are the basis for better understanding soil carbon sequestration of mollisols. Based on a 31-year long-term field experiment located at the Heilongjiang Academy of Agricultural Sciences (Harbin) , soil samples under six treatments were separated by size-fractionation method to explore changes and distribution of SOC and TN in coarse sand, fine sand, silt and clay from the top layer (0-20 cm) and subsurface layer (20-40 cm). Results showed that long-term application of manure (M) increased the percentages of SOC and TN in coarse sand and clay size fractions. In the top layer, application of nitrogen, phosphorus and potassium fertilizers combined with manure (NPKM) increased the percentages of SOC and TN in coarse sand by 191.3% and 179.3% compared with the control (CK), whereas M application increased the percentages of SOC and TN in clay by 45% and 47% respectively. For subsurface layers, the increase rates of SOC and TN in corresponding parts were lower than that in top layer. In the surface and subsurface layers, the percentages of SOC storage in silt size fraction accounted for 42%-63% and 48%-54%, TN storage accounted for 34%-59% and 41%-47%, respectively. The enrichment factors of SOC and TN in coarse sand and clay fractions of surface layers increased significantly under the treatments with manure. The SOC and TN enrichment factors were highest in the NPKM, being 2.30 and 1.88, respectively, while that in the clay fraction changed little in the subsurface layer.

  14. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    Directory of Open Access Journals (Sweden)

    Diego Javier Jiménez

    2011-09-01

    Full Text Available With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-Sucrose agar obtaining a recovery of 40%. Twenty four isolates were evaluated for colony and cellular morphology, pigment production and metabolic activities. Molecular characterization was carried out using amplified ribosomal DNA restriction analysis (ARDRA. After digestion of 16S rDNA Y1-Y3 PCR products (1487pb with AluI, HpaII and RsaI endonucleases, a polymorphism of 16% was obtained. Cluster analysis showed three main groups based on DNA fingerprints. Comparison between ribotypes generated by isolates and in silico restriction of 16S rDNA partial sequences with same restriction enzymes was done with Gen Workbench v.2.2.4 software. Nevertheless, Y1-Y2 PCR products were analysed using BLASTn. Isolate C5T from tomato (Lycopersicon esculentum grown soils presented the same in silico restriction patterns with A. chroococcum (AY353708 and 99% of similarity with the same sequence. Isolate C5CO from cauliflower (Brassica oleracea var. botrytis grown soils showed black pigmentation in Ashby-Benzoate agar and high similarity (91% with A. nigricans (AB175651 sequence. In this work we demonstrated the utility of molecular techniques and bioinformatics tools as a support to conventional techniques in characterization of the genus Azotobacter from vegetable-grown soils.

  15. Source identification of particulate organic matter in view of land uses in Shingil Creek using carbon, nitrogen and oxygen isotope ratios.

    Science.gov (United States)

    Kim, Dahae; Lee, Yeonjung; Ock, Giyoung; Kang, Sujin; Kim, Minseob; Choi, Jongwoo; Shin, Kyung-Hoon

    2016-04-01

    Anthropogenic inputs influence the quality and quantity of organic matter, which is important for recycling of nutrients and chemical elements. Stable isotope techniques are useful for distinguishing the origin of organic matter by using the characteristics that are distinctive between sources. Artificial Lake Shihwa, especially the Shingil creek is typically under the strong anthropogenic pressure with continuous continental inputs from various sources. Hence in this study, the characteristics and sources of organic matter in water and surface sediment of the Shingil creeks in the rural, urban, and industrial areas were evaluated by using carbon, nitrogen and oxygen isotope ratios, by analyzing samples collected during the rainy season and dry season. Among the input sources, the organic matter derived from industrial regions showed distinct nitrogen isotope values compared to other sites. Further studies including other techniques such as hydrogen isotope will provide an insight into the development of a strategy for effective water quality management in Lake Shihwa

  16. Short-term effects of grazing intensity and nitrogen fertilization on soil organic carbon pools under perennial grass pastures in the Southeastern USA

    Science.gov (United States)

    Pasture management can have important implications on the amounts and long-term stability of soil organic carbon (SOC). We investigated the short-term impacts of grazing intensity and nitrogen (N) fertilization levels on C dynamics into the various SOC pools in rotationally stocked ‘Tifton 85’ bermu...

  17. Effect of organic fertiliser residues from rice production on nitrogen fixation of soya (Glycine max L. Merrill, Chiang Mai 60 variety

    Directory of Open Access Journals (Sweden)

    Nattida Luangmaka

    2013-09-01

    Full Text Available A field study was undertaken on the residual effect of organic fertilisers applied to the preceding rice cropping on nitrogen fixation of soya in a rice-soya cropping system. The experiment was conducted on a farmer’s lowland paddy in Mae Rim district, Chiang Mai province, Thailand. Organic fertiliser treatments assigned were: 1 control (no fertiliser, 2 animal manure of cattle (AM, 3 compost (CP, 4 azolla (AZ, 5 AM + CP, 6 AM + AZ, 7 CP + AZ and 8 AM + CP + AZ. Soya seeds were planted without rhizobial inoculation in December 2011, four months after the application of organic fertilisers. Nodule weight, total shoot nitrogen accumulation and relative ureide index at various growth stages were recorded as the indices of nitrogen fixation. Results of the study demonstrate that the residues from the application the organic fertilisers of narrow C/N ratios during the land preparation for rice cropping four months before soya cultivation promoted nitrogen fixation by native rhizobia.

  18. Variations of Microbial Communities and the Contents and Isotopic Compositions of Total Organic Carbon and Total Nitrogen in Soil Samples during Their Preservation

    Institute of Scientific and Technical Information of China (English)

    TAO Qianye; LI Yumei; WANG Guo'an; QIAO Yuhui; LIU Tung-Sheng

    2009-01-01

    Semi-sealed preservation of soil samples at difierent moisture of 4%and 23%,respectively, was simulated to observe the variations of soil microbiaI communities and determine the contents and isotopic compositions of the total organic carbon and total nitrogen on the 7th and 30th day, respectively.The results show that during preservation,the quantity of microbial communities tended to increase first and then decrease,with a wider variation range at higher moisture(23%).At the moisture content of 23%,the microbial communities became more active on the 7th day.but less after 30 days,and their activity Was stable with little fluctuation at the moisture content of 4%.However. there were no significant changes in the contents and isotopic compositions of the total organic carbon and total nitrogen.During preservation.the responses of soil microbes to the environment are more sensitive to changes in the total nitrogen and organic carbon contents.It is thus suggested that the variations of microbial communities have not exerted remarkable impacts on the isotope compositions of the total nitrogen and total organic carbon.

  19. Organic Reference Materials for Hydrogen, Carbon, and Nitrogen Stable Isotope-Ratio Measurements : Caffeines, n-Alkanes, Fatty Acid Methyl Esters, Glycines, L-Valines, Polyethylenes, and Oils

    NARCIS (Netherlands)

    Schimmelrnann, Arndt; Qi, Haiping; Coplen, Tyler B.; Brand, Willi A.; Fong, Jon; Meier-Augenstein, Wolfram; Kemp, Helen F.; Toman, Blaza; Ackermann, Annika; Assonov, Sergey; Aerts-Bijma, Anita T.; Brejcha, Ramona; Chikaraishi, Yoshito; Darwish, Tamim; Elsner, Martin; Gehre, Matthias; Geilmann, Heike; Groeing, Manfred; Helie, Jean-Francois; Herrero-Martin, Sara; Meijer, Harro A. J.; Sauer, Peter E.; Sessions, Alex L.; Werner, Roland A.

    2016-01-01

    An international project developed, quality-tested, and determined isotope-delta values of 19 new organic reference materials (RMs) for hydrogen, carbon, and nitrogen stable isotope-ratio measurements, in addition to analyzing pre-existing RMs NBS 22 (oil), IAEA-CH-7 (polyethylene foil), and IAEA-60

  20. Removal of nitrogen and organic matter in a submerged-membrane bioreactor operating in a condition of simultaneous nitrification and denitrification

    Directory of Open Access Journals (Sweden)

    Izabela Major Barbosa

    2016-04-01

    Full Text Available This study evaluated the removal of nitrogen and organic matter in a membrane bioreactor system operating in a condition of simultaneous nitrification and denitrification controlled by intermittent aeration. A submerged-membrane system in a bioreactor was used in a pilot scale to treat domestic wastewater. The dissolved oxygen concentration was maintained between 0.5 and 0.8 mg L-1. The concentration of the mixed liquor suspended solids (MLSS in the system ranged from 1 to 6 g L-1. The system efficiency was evaluated by the removal efficiency of organic matter, quantified by Chemical Oxygen Demand (COD, Biochemical Oxygen Demand (BOD5 and Total Organic Carbon (TOC. Nitrogen removal was assessed by quantifying Total Kjeldahl Nitrogen (TKN and ammonia nitrogen. During the system start-up, the removal efficiencies of COD and NTK were around 90% and 80%, respectively. After the simultaneous nitrification and denitrification (SND conditions were established, the removal efficiencies of COD and NTK were 70% and 99%, respectively. These results showed that sewage treatment with the membrane bioreactor (MBR system, operating with simultaneous nitrification and denitrification conditions, was able to remove organic matter and promote nitrification and denitrification in a single reactor, producing a high-quality permeate.

  1. Heterogeneous and Photochemical Reactions Involving Surface Adsorbed Organics: Common Lignin Pyrolysis Products With Nitrogen Dioxide.

    Science.gov (United States)

    Hinrichs, R. Z.; Nichols, B. R.; Rapa, C.; Costa, V.

    2009-05-01

    Solid-air interfaces, such as airborne particulate matter and ground level surfaces, provide unique supports for tropospheric heterogeneous chemistry. These interfaces commonly contain surface adsorbed organics, such as lignin pyrolysis products, that can significantly alter their physical and chemical properties. Attenuated total reflectance infrared spectroscopy (ATR-FTIR) provides an ideal tool for monitoring chemical changes in thin organic films during heterogeneous and photochemical reactions. Phenolic compounds, with and without co- adsorbed photosensitizers, were exposed to NO2 concentrations in the parts-per-billion range at 300 K and 20% relative humidity. Catechol, when mixed with benzophenone or dicyclohexylketone, formed 4- nitrocatechol as the dominant product under dark conditions. Deuterating the catechol alcohol groups caused the initial rate of reaction to decrease by a factor of 3.3±0.5, consistent with formation of the ortho- semiquinone radical as the rate determining step. The rate of 4-nitrocatechol formation did not increase under illuminated conditions, even with the presence of benzophenone a well known photosensitizer. UV-A/visible radiation did, however, initiate a photochemical reaction between benzophenone and 4-nitrocatechol, likely forming high molecular weight polymerization products. In contrast, 2-ethoxyphenol displayed no reactivity with NO2, even under illuminated conditions with a photosensitizer. Implications for the fate of lignin pyrolysis products, which are prevalent in biomass combustion smoke, will be discussed.

  2. Throughfall and bulk deposition of dissolved organic nitrogen to holm oak forests in the Iberian Peninsula : flux estimation and identification of potential sources

    OpenAIRE

    Izquieta-Rojano, Sheila; García-Gomez, H.; Aguillaume Rodríguez-O'connor, Laura; Santamaría Ulecia, Jesús Miguel; Y. S. Tang; Santamaría, C.; Valiño, F.; Lasheras, E. (Esther); Alonso, R.; Àvila i Castells, Anna; Cape, J. N.; Elustondo, David

    2016-01-01

    Acknowledgments: the research leading to these results has received funding from the COST organism (European cooperation in science and technology), through the COST Action FP0903 “Climate change and forest mitigation and adaptation in the polluted environment” under the grant number COST-STSM-ECOST-STSM-FP0903-291012-019757. Deposition of dissolved organic nitrogen (DON) in both bulk precipitation (BD) and canopy throughfall (TF) has been measured for the first time in the western Mediter...

  3. Analyzing blends of herbivore-induced volatile organic compounds with factor analysis: revisiting "cotton plant, Gossypium hirsutum L., defense in response to nitrogen fertilization".

    Science.gov (United States)

    Chen, Yigen

    2013-04-01

    Many herbivorous, predaceous, and parasitic insects use constitutive and herbivore-induced volatile organic compounds (VOCs) to locate their respective host plant, prey, and hosts. Multivariate statistical tools (e.g., factor analysis) are recognized increasingly as an appropriate approach for analyzing intercorrelated data such as presence/absence or quantities of VOCs. One challenge of implementing factor analysis is determining how many new variables (factors) to retain in the final analysis. I demonstrate a method proposed by Johnson and Wichern to mitigate this problem by using VOC data published in Chen et al. The advantage of using loading (or weight) transformation in interpretation of new variables was also illustrated in the example. Factor analysis found similar nitrogen fertilization effects on VOC production as those in Chen et al. Similarities were 1) nitrogen fertilization interacted with herbivore damage status on VOC production: at low nitrogen (42 ppm) level, beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), damage elicited increases in VOC production, whereas at high nitrogen (196 ppm) VOC production was suppressed; 2) nitrogen fertilization did not affect limonene, alpha-pinene, and beta-pinene production. The seven individual VOCs significantly affected by nitrogen fertilization in Chen et al. were (Z)-3-hexenal, (E)-2-hexenal, (E)-beta-farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), alpha-bergamotene, gamma-bisabolene, and bisabolol, of which only three ((E)-beta-farnesene, gamma-bisabolene, and bisabolol) weighed heavily on factor 1 in the current study.

  4. Geo-pedological control of soil organic carbon and nitrogen stocks at the landscape scale

    Science.gov (United States)

    Barré, Pierre; Durand, Hermine; Chenu, Claire; Meunier, Patrick; Montagne, David; Castel, Géraldine; Billiou, Daniel; Cécillon, Lauric

    2015-04-01

    Geo-pedology, here defined as soil type (or Reference Soil Group) and parent material, can have a major impact on ecosystem (vegetation and soil) functioning. Geo-pedology can therefore deeply influence soil organic matter (SOM) stock. Nonetheless, the effect of geo-pedology on soil organic C (SOC) and N stocks has seldom been investigated. Indeed, factors known to influence SOM stocks such as land use and climate frequently co-vary with geo-pedology, so that testing the influence on SOM stocks of the factor "geo-pedology" alone is challenging. In this work, we studied SOM stocks of forest and cropland soils in a small landscape (17 km²) of the Paris basin (AgroParisTech domain, Thiverval-Grignon, France). We collected soil samples (0-30 cm) in 50 forest and cropland plots, located in five geo-pedological contexts: Luvisols developed on loess deposit, Cambisols developed on hard limestone, Cambisols developed on shelly limestone, Cambisols developed on chalk and Cambisols developed on calcareous clay deposits. We then determined SOM stocks (organic C and total N) and SOM distribution across different particle size fractions (coarse sand, fine sand and silt-clay). As expected, SOC stocks were much higher in forests (~ 83 tC ha-1) than in cultivated soils (~ 49 tC ha-1). Interestingly, Cambisols had higher SOC stocks than Luvisols (69 vs 56 tC ha-1) and the difference between SOC stocks in forest and cultivated soils was much higher for Cambisols compared to Luvisols. Within Cambisols, parent material did not influence SOC stocks but the interaction between parent material and land use was significant, indicating that the effect of land use on SOC stocks was modulated by parent material. Similar trends were observed for soil N stocks. Conversely, soil type and parent material did not control SOM distribution in soil size fractions, while forest soils showed a higher distribution of SOC and N in the sand-size fraction than cropland soils. Overall, our study evidenced

  5. Water-quality assessment of the eastern Iowa basins- nitrogen, phosphorus, suspended sediment, and organic carbon in surface water, 1996-98

    Science.gov (United States)

    Becher, Kent D.; Kalkhoff, Stephen J.; Schnoebelen, Douglas J.; Barnes, Kimberlee K.; Miller, Von E.

    2001-01-01

    Twelve sites on streams and rivers in the Eastern Iowa Basins study unit were sampled monthly and during selected storm events from March 1996 through September 1998 to assess the occurrence, distribution, and transport of nitrogen, phosphorus, suspended sediment, and organic carbon as part of the U.S. Geological Survey’s National Water-Quality Assessment Program. One site was dropped from monthly sampling after 1996. Dissolved nitrogen and phosphorus were detected in every water sample collected. Nitrate accounted for 92 percent of the total dissolved nitrogen. About 22 percent of the samples had nitrate concentrations that exceeded the U.S. Environmental Protection Agency’s maximum contaminant level of 10 milligrams per liter as nitrogen for drinking-water regulations. The median concentration of total dissolved nitrogen for surface water in the study unit was 7.2 milligrams per liter. The median total phosphorus concentration for the study unit was 0.22 milligram per liter. About 75 percent of the total phosphorus concentrations exceeded the U.S. Environmental Protection Agency recommended total phosphorus concentration of 0.10 milligram per liter or less to minimize algal growth. Median suspended sediment and dissolved organic-carbon concentrations for the study unit were 82 and 3.5 milligrams per liter, respectively.

  6. Engineering soil organic matter quality: Biodiesel Co-Product (BCP) stimulates exudation of nitrogenous microbial biopolymers.

    Science.gov (United States)

    Redmile-Gordon, Marc A; Evershed, Richard P; Kuhl, Alison; Armenise, Elena; White, Rodger P; Hirsch, Penny R; Goulding, Keith W T; Brookes, Philip C

    2015-12-01

    Biodiesel Co-Product (BCP) is a complex organic material formed during the transesterification of lipids. We investigated the effect of BCP on the extracellular microbial matrix or 'extracellular polymeric substance' (EPS) in soil which is suspected to be a highly influential fraction of soil organic matter (SOM). It was hypothesised that more N would be transferred to EPS in soil given BCP compared to soil given glycerol. An arable soil was amended with BCP produced from either 1) waste vegetable oils or 2) pure oilseed rape oil, and compared with soil amended with 99% pure glycerol; all were provided with (15)N labelled KNO3. We compared transfer of microbially assimilated (15)N into the extracellular amino acid pool, and measured concomitant production of exopolysaccharide. Following incubation, the (15)N enrichment of total hydrolysable amino acids (THAAs) indicated that intracellular anabolic products had incorporated the labelled N primarily as glutamine and glutamate. A greater proportion of the amino acids in EPS were found to contain (15)N than those in the THAA pool, indicating that the increase in EPS was comprised of bioproducts synthesised de novo. Moreover, BCP had increased the EPS production efficiency of the soil microbial community (μg EPS per unit ATP) up to approximately double that of glycerol, and caused transfer of 21% more (15)N from soil solution into EPS-amino acids. Given the suspected value of EPS in agricultural soils, the use of BCP to stimulate exudation is an interesting tool to consider in the theme of delivering sustainable intensification.

  7. Engineering soil organic matter quality: Biodiesel Co-Product (BCP) stimulates exudation of nitrogenous microbial biopolymers

    Science.gov (United States)

    Redmile-Gordon, Marc A.; Evershed, Richard P.; Kuhl, Alison; Armenise, Elena; White, Rodger P.; Hirsch, Penny R.; Goulding, Keith W.T.; Brookes, Philip C.

    2015-01-01

    Biodiesel Co-Product (BCP) is a complex organic material formed during the transesterification of lipids. We investigated the effect of BCP on the extracellular microbial matrix or ‘extracellular polymeric substance’ (EPS) in soil which is suspected to be a highly influential fraction of soil organic matter (SOM). It was hypothesised that more N would be transferred to EPS in soil given BCP compared to soil given glycerol. An arable soil was amended with BCP produced from either 1) waste vegetable oils or 2) pure oilseed rape oil, and compared with soil amended with 99% pure glycerol; all were provided with 15N labelled KNO3. We compared transfer of microbially assimilated 15N into the extracellular amino acid pool, and measured concomitant production of exopolysaccharide. Following incubation, the 15N enrichment of total hydrolysable amino acids (THAAs) indicated that intracellular anabolic products had incorporated the labelled N primarily as glutamine and glutamate. A greater proportion of the amino acids in EPS were found to contain 15N than those in the THAA pool, indicating that the increase in EPS was comprised of bioproducts synthesised de novo. Moreover, BCP had increased the EPS production efficiency of the soil microbial community (μg EPS per unit ATP) up to approximately double that of glycerol, and caused transfer of 21% more 15N from soil solution into EPS-amino acids. Given the suspected value of EPS in agricultural soils, the use of BCP to stimulate exudation is an interesting tool to consider in the theme of delivering sustainable intensification. PMID:26635420

  8. [Change characteristics of rice yield and soil organic matter and nitrogen contents under various long-term fertilization regimes].

    Science.gov (United States)

    Huang, Jing; Gao, Ju-Sheng; Zhang, Yang-Zhu; Qin, Dao-Zhu; Xu, Ming-Gang

    2013-07-01

    A long-term (1982-2010) field experiment was conducted in the Red Soil Experiment Station of Chinese Academy of Agricultural Sciences in Qiyang County of Hunan Province, South-central China to investigate the dynamic changes of rice yield and soil organic matter (OM) and nitrogen contents under different fertilization treatments. The treatments included NPK, NPKM (M: manure), NPM, NKM, PKM, M, and CK. Fertilization increased the soil OM, total N, and alkaline-hydrolysable N contents and the rice yield. In treatment NPKM, the rice yield across the 28 years maintained at the highest level; while in treatment NPK, the yield showed a decreasing trend, being lower than that in other fertilization treatments. In the treatments applied with manure only or in combining with chemical fertilizers, the soil OM content increased rapidly in the first 16 years, and then fluctuated around a constant level (29.42-39.32 g x kg(-1)). In the treatments of chemical fertilization, the soil OM content only had a quicker increase in the first 8 years, and then fluctuated within a relatively stable range. Fertilization with manure increased the soil OM significantly, as compared to fertilization with chemical fertilizers only. The soil total N content in all fertilization treatments showed a rapid increase in the first 8 years, and the increment was the highest in treatment NPKM. The soil alkaline-hydrolysable N content in all fertilization treatments had a slower increase in the first 12 years, with an average annual increment of 0.66-2.25 mg x kg(-1) x a(-1). In 1994-1998, the soil alkaline-hydrolysable N content in fertilization treatments had a quicker increase, with an average annual increment of 6.45-32.45 mg x kg(-1) x a(-1); but after 1998, the soil alkaline-hydrolysable N content had a slight decrease. It was concluded that organic fertilization was the key measure to stably improve the physical and chemical properties and the productivity of red paddy soils by increasing their

  9. Toxicity of four nitrogen-heterocyclic polyaromatic hydrocarbons (NPAHs) to soil organisms.

    Science.gov (United States)

    Kobetičová, K; Bezchlebová, J; Lána, J; Sochová, I; Hofman, J

    2008-11-01

    The aims of this study were: (i) to investigate the toxicity of N-heterocyclic polyaromatic hydrocarbons (NPAHs) quinoline, acridine, phenazine, and 1,10-phenanthroline to the soil invertebrates Eisenia fetida, Enchytraeus crypticus, Folsomia candida, and Caenorhabditis elegans, (ii) to compare the toxicity of four NPAHs and the species sensitivity, and (iii) to discuss possible risks of these compounds in soils. Different toxicities were found for the tested NPAHs which might be partially explained by their structure and properties. Effect concentrations expressed as soil pore-water concentrations were related to log K(ow), which indicated narcosis as the most probable mode of toxic action. The species sensitivity decreased in the rank: springtails >enchytraeids=earthworms> nematodes. Predicted no-effect concentration (PNEC) values were calculated for all tested species giving values from 0.5 to 6.8 mg/kg. It is unlikely that there is a risk for soil organisms in natural soils where lower NPAHs concentrations are expected.

  10. Combining organic and inorganic nitrogen fertilisation reduces N2O emissions from cereal crops

    DEFF Research Database (Denmark)

    Nyamadzawo, George; Shi, Yeufeng; Chirinda, Ngonidzashe

    2017-01-01

    ha−1 cattle manure-N. In China, treatments were; (i) Control, (ii) 300 kg N ha−1 Urea, (iii) 92 kg N ha−1 Urea plus 65 kg ha−1 chicken (Gallus domesticus) manure-N, (iv) 100 kg N ha−1 Urea and (v) 100 kg N ha−1 control release Urea. Our results showed that under both temperate and tropical conditions...... emissions were measured from maize and winter wheat plots. In Zimbabwe the treatments were; (i) Control, (ii) 60 kg N ha−1 ammonium nitrate (NH4NO3), (iii) 120 kg N ha−1 NH4NO3, (iv) 60 kg ha−1 cattle (Bos primigenius) manure-N, plus 60 kg N ha−1 NH4NO3, (v) 60 kg N ha−1 cattle manure-N, and (vi) 120 kg N......, integrated nutrient management resulted in lower N2O emissions compared to inorganic fertilizers which had higher total and yield-scale N2O emissions. We conclude that by combining organic and inorganic N sources, smallholder farmers in both China and Zimbabwe, and other countries with similar climatic...

  11. Enhancing carbon and nitrogen sequestration in reclaimed soils through organic amendments and chiseling

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, R.K.; Lal, R.; Jacinthe, P.A. [Ohio State University, Columbus, OH (United States). School of Environmental & Natural Resources

    2009-05-15

    The choice of reclamation techniques could affect restoration success, ecosystem productivity, and the capacity of reclaimed mine soil (RMS) to sequester soil organic carbon (SOC). A field experiment was conducted at three reclaimed coal mine sites across eastern Ohio to assess the impact of several reclamation techniques on biomass production, soil properties, and temporal changes in SOC and N pools. Amendments and reclamation practices tested were: normal reclamation practice (NRP, control), cow (Bos taurus) manure (10 Mg ha{sup -1}), mulching with oat straw (15 Mg hat), and chiseling (30-cm depth). At each site, all treatments were applied in triplicate to experimental plots in accord with a randomized complete block design. After 5 yr of restoration, results showed no effect of mulching on any of the soil properties investigated but significant effects of manuring and chiseling. During that period, SOC sequestration rates ranged between 0.6 and 2.8 Mg C ha{sup -1} yr{sup -1}, with the highest rates recorded in the manure-treated plots. Aboveground biomass production, biomass N content, and soil N and SOC pools were also significantly higher in the manure and chiseling treatments, probably due to greater exploration of the soil volume by plant roots and more efficient uptake of water and available nutrients. Ecosystem C (SOC + biomass C) in these two treatments also exceeded that in the NRP by 25 to 27 Mg C ha{sup -}. Thus, manure application and chiseling are effective reclamation practices for restoring RMS.

  12. Use of GIS and ancillary variables to predict volatile organic compound and nitrogen dioxide levels at unmonitored locations

    Science.gov (United States)

    Smith, Luther; Mukerjee, Shaibal; Gonzales, Melissa; Stallings, Casson; Neas, Lucas; Norris, Gary; Özkaynak, Halûk

    In late 1999, passive air sampling of nitrogen dioxide (NO 2) and volatile organic compounds was conducted at 22 school locations and two intensive sites in El Paso, Texas. Our goal was to predict concentrations of NO 2 and benzene, toluene, ethylbenzene, o-xylene, and m, p-xylene at a total of 55 schools. The predictive equations were developed by regressing the passive monitor measurements at the 22 monitored schools on land-use variables derived from a geographic information system (GIS). These GIS-based ancillary variables included distance to the nearest border crossing, elevation, population density, distance to roads with specified traffic volumes, traffic intensity around the schools, and distance to the nearest petroleum facility. The reliability of the predictive equations was assessed at the two intensive monitoring sites. For all pollutants, the most useful predictive ancillary variables were elevation, population density, distance to a border crossing, and distance to a petroleum facility. For estimating NO 2, traffic intensity was also important.

  13. Role of Anthropogenic Volatile Organic Compounds and Nitrogen Oxides as Ozone Precursors in the Wintertime over East Asia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Meigen; Itsushi Uno

    2002-01-01

    As an exercise in model sensitivity, the Models-3 Community Multiscale Air Quality (CMAQ) modeling system with meteorological fields from the Regional Atmospheric Modeling System (RAMS) was applied to study the response of photochemical oxidants to systematic increases in anthropogenic volatile organic compounds (VOC) and nitrogen oxides (NOx) emissions in January 1997 over East Asia. Three simulations-one base case and two sensitivity simulations were carried out. Two sensitivity simulations were performed by assuming a 35% separate increase in anthropogenic VOC and NOx emissions comparing with the base case. Biogenic VOC emissions were held constant across the sensitivity simulations. To evaluate the model performance, ozone mixing ratios (O3) from the base case simulation were compared with surface observations at five remote sites in Japan, and it was found that the model reproduces most of the important features in the observations.Monthly average O3 concentrations in the daytime were examined to gain an understanding of how the increase in anthropogenic emissions affected the overall chemical system for each sensitivity simulation.

  14. Assessing traffic and industrial contributions to ambient nitrogen dioxide and volatile organic compounds in a low pollution urban environment.

    Science.gov (United States)

    Oiamo, Tor H; Johnson, Markey; Tang, Kathy; Luginaah, Isaac N

    2015-10-01

    Land use regression (LUR) modeling is an effective method for estimating fine-scale distributions of ambient air pollutants. The objectives of this study are to advance the methodology for use in urban environments with relatively low levels of industrial activity and provide exposure assessments for research on health effects of air pollution. Intraurban distributions of nitrogen dioxide (NO2) and the volatile organic compounds (VOCs) benzene, toluene and m- and p-xylene were characterized based on spatial monitoring and LUR modeling in Ottawa, Ontario, Canada. Passive samplers were deployed at 50 locations throughout Ottawa for two consecutive weeks in October 2008 and May 2009. Land use variables representing point, area and line sources were tested as predictors of pooled pollutant distributions. LUR models explained 96% of the spatial variability in NO2 and 75-79% of the variability in the VOC species. Proximity to highways, green space, industrial and residential land uses were significant in the final models. More notably, proximity to industrial point sources and road network intersections were significant predictors for all pollutants. The strong contribution of industrial point sources to VOC distributions in Ottawa suggests that facility emission data should be considered whenever possible. The study also suggests that proximity to road network intersections may be an effective proxy in areas where reliable traffic data are not available.

  15. Effects of feedstock carbon to nitrogen ratio and organic loading on foaming potential in mesophilic food waste anaerobic digestion.

    Science.gov (United States)

    Tanimu, Musa Idris; Mohd Ghazi, Tinia Idaty; Harun, Mohd Razif; Idris, Azni

    2015-05-01

    Foaming problem which occurred occasionally during food waste (FW) anaerobic digestion (AD) was investigated with the Malaysian FW by stepwise increase in organic loading (OL) from 0.5 to 7.5 g VS/L. The FW feedstock with carbon to nitrogen (C/N) ratio of 17 was upgraded to C/N ratio of 26 and 30 by mixing with other wastes. The digestion which was carried out at 37 °C in 1-L batch reactors showed that foam formation initiated at OL of 1.5 g VS/L and was further enhanced as OL of feedstock was increased. The digestion foaming reached its maximum at OL of 5.5 g VS/L and did not increase further even when OL was increased to 7.5 g VS/Ld. Increase in the C/N ratio of feedstock significantly enhanced the microbial degradation activity, leading to better removal of foam causing intermediates and reduced foaming in the reactor by up to 60%.

  16. Influence of Organic Nitrogen Compounds on Chlorine Disinfection%有机氮类化合物对氯消毒影响研究

    Institute of Scientific and Technical Information of China (English)

    徐华; 杨艳玲; 王花平; 梁贞淑

    2012-01-01

    受污染饮用水水源中都含多种有机氮类化合物,会对氯消毒效果产生影响.试验采用有机氮类化合物甘氨酸、亮氨酸、赖氨酸、天冬氨酸、半胱氨酸和甲胺,研究了有机氮类化合物浓度和pH值对消毒效果的影响.结果表明,有机氮类化合物都会和自由氯迅速反应生成大量的有机氯胺,使消毒效果显著下降;不同有机氮类化合物对氯消毒效果的影响有很大差异,半胱氨酸的影响最为明显,使得氯几乎丧失消毒能力.因此,对有机氮类化合物的含量和去除应考虑改善氯的投加方式或氯消毒工艺,建立安全有效的消毒方法.%Many organic nitrogen compounds are contained in polluted resource of drinking water, which seriously influence on chlorine disinfection. Typical organic nitrogen compounds including glycine, leucine, lysine, aspartic acid, cysteine, and methylamine were applied. Influences of organic nitrogen compound dosage and pH on disinfection effects are investigated. Results show that many organic chloramines are produced by prompt action of organic nitrogen compounds and free chlorine to decrease disinfection effects pronounced. Influences on chlorine disinfection effects are different through different organic nitrogen compounds. Influence of cysteine is most obvious to cause chlorine losing disinfection capacity. Therefore, contents and removal of organic nitrogen compounds must be attached. The chlorine dosing mode and chlorine disinfection process can be improved and the effective safe disinfection method must be established.

  17. Moisture and vegetation controls on decadal-scale accrual of soil organic carbon and total nitrogen in restored grasslands

    Science.gov (United States)

    O'Brien, S. L.; Jastrow, J.D.; Grimley, D.A.; Gonzalez-Meler, M. A.

    2010-01-01

    Revitalization of degraded landscapes may provide sinks for rising atmospheric CO2, especially in reconstructed prairies where substantial belowground productivity is coupled with large soil organic carbon (SOC) deficits after many decades of cultivation. The restoration process also provides opportunities to study the often-elusive factors that regulate soil processes. Although the precise mechanisms that govern the rate of SOC accrual are unclear, factors such as soil moisture or vegetation type may influence the net accrual rate by affecting the balance between organic matter inputs and decomposition. A resampling approach was used to assess the control that soil moisture and plant community type each exert on SOC and total nitrogen (TN) accumulation in restored grasslands. Five plots that varied in drainage were sampled at least four times over two decades to assess SOC, TN, and C4- and C3-derived C. We found that higher long-term soil moisture, characterized by low soil magnetic susceptibility, promoted SOC and TN accrual, with twice the SOC and three times the TN gain in seasonally saturated prairies compared with mesic prairies. Vegetation also influenced SOC and TN recovery, as accrual was faster in the prairies compared with C3-only grassland, and C4-derived C accrual correlated strongly to total SOC accrual but C3-C did not. High SOC accumulation at the surface (0-10 cm) combined with losses at depth (10-20 cm) suggested these soils are recovering the highly stratified profiles typical of remnant prairies. Our results suggest that local hydrology and plant community are critical drivers of SOC and TN recovery in restored grasslands. Because these factors and the way they affect SOC are susceptible to modification by climate change, we contend that predictions of the C-sequestration performance of restored grasslands must account for projected climatic changes on both soil moisture and the seasonal productivity of C4 and C3 plants. ?? 2009 Blackwell

  18. Effect of ecosystem retrogression on stable nitrogen and carbon isotopes of plants, soils and consumer organisms in boreal forest islands.

    Science.gov (United States)

    Hyodo, Fujio; Wardle, David A

    2009-07-01

    In the prolonged absence of catastrophic disturbance, ecosystem retrogression occurs, and this involves increased nutrient limitation, and reduced aboveground and belowground ecosystem processes rates. Little is known about how the nitrogen and carbon stable isotope ratios (delta(15)N and delta(13)C) of plants, soils and consumer organisms respond to retrogression in boreal forests. We investigated a 5000 year chronosequence of forested islands in the boreal zone of northern Sweden, for which the time since lightning-induced wildfire increases with decreasing island size, leading to ecosystem retrogression. For this system, tissue delta(15)N of three abundant plant species (Betula pubescens, Vaccinium myrtillus and Pleurozium schreberi) and humus all increased as retrogression proceeded. This is probably due to enhanced ecosystem inputs of N by biological fixation, and greater dependency of the plants on organic N during retrogression. The delta(13)C of B. pubescens and plant-derived humus also increased during retrogression, probably through nutrient limitation increasing plant physiological stress. Unlike the plants, delta(15)N of invertebrates (lycosid spiders and ants) did not increase during retrogression, probably because of their partial dependence on aquatic-derived prey that had a variable delta(15)N signature. The delta(13)C of the invertebrates increased as retrogression proceeded and converged towards that of an aquatic prey source (chironomid flies), suggesting increased dependence on aquatic-derived prey during retrogression. These results show that measurement of delta(15)N and delta(13)C of plants, soils, and consumers across the same environmental gradient can provide insights into environmental factors that drive both the aboveground and belowground subsystems, as well as the linkages between them.

  19. [Effects of nitrogen application and winter green manure on soil active organic carbon and the soil carbon pool management index].

    Science.gov (United States)

    Yang, Bin-Juan; Huang, Guo-Qin; Lan, Yan; Chen, Hong-Jun; Wang, Shu-Bin

    2014-10-01

    Based on a cropping system of "winter green manure-double rice", the 4 x 4 two-factor test was used to study the effects of different nitrogen (N) application levels and winter green manure application on soil active organic carbon (AOC) and the C pool management index. The aim was to explore the ecological effects of winter green manure on soil improvement and determine the appropriate application levels of N fertilizer and winter green manure for improved rice yield. Results were as follows: 1) Compared with the control, the SOC and AOC contents increased by 22.2% and 26.7%, respectively, under the green manure only treatment, but the SOC contents decreased by 0.6%-3.4% under the single N fertilizer treatment. Compared with the control, the soil C pool management index increased by 24.55 and 15.17 under the green manure only and green manure plus N fertilizer treatments, respectively, and reduced by 2.59 under the single N fertilizer treatment. Compared with no fertilization, the average microbial biomass carbon (MBC) increased by 54.0%, 95.2% and 14.3% under the green manure, green manure plus N fertilizer and single N fertilizer treatments, respectively. 2) The soil AOC content was significantly positively correlated with the C pool management index (P index, and the correlation coefficient was significantly greater than that with the total organic C. These results suggested that application of winter green manure at proper rates with inorganic fertilizer could increase SOC contents and the soil C pool management index, improve soil quality and fertility.

  20. Maximum soil organic carbon storage in Midwest U.S. cropping systems when crops are optimally nitrogen-fertilized

    Science.gov (United States)

    Barker, Daniel W.; Helmers, Matthew J.; Miguez, Fernando E.; Olk, Daniel C.; Sawyer, John E.; Six, Johan; Castellano, Michael J.

    2017-01-01

    Nitrogen fertilization is critical to optimize short-term crop yield, but its long-term effect on soil organic C (SOC) is uncertain. Here, we clarify the impact of N fertilization on SOC in typical maize-based (Zea mays L.) Midwest U.S. cropping systems by accounting for site-to-site variability in maize yield response to N fertilization. Within continuous maize and maize-soybean [Glycine max (L.) Merr.] systems at four Iowa locations, we evaluated changes in surface SOC over 14 to 16 years across a range of N fertilizer rates empirically determined to be insufficient, optimum, or excessive for maximum maize yield. Soil organic C balances were negative where no N was applied but neutral (maize-soybean) or positive (continuous maize) at the agronomic optimum N rate (AONR). For continuous maize, the rate of SOC storage increased with increasing N rate, reaching a maximum at the AONR and decreasing above the AONR. Greater SOC storage in the optimally fertilized continuous maize system than in the optimally fertilized maize-soybean system was attributed to greater crop residue production and greater SOC storage efficiency in the continuous maize system. Mean annual crop residue production at the AONR was 22% greater in the continuous maize system than in the maize-soybean system and the rate of SOC storage per unit residue C input was 58% greater in the monocrop system. Our results demonstrate that agronomic optimum N fertilization is critical to maintain or increase SOC of Midwest U.S. cropland. PMID:28249014

  1. Increasing trends of dissolved organic nitrogen (DON) in temperate forests under recovery from acidification in Flanders, Belgium.

    Science.gov (United States)

    Verstraeten, Arne; Verschelde, Pieter; De Vos, Bruno; Neirynck, Johan; Cools, Nathalie; Roskams, Peter; Hens, Maarten; Louette, Gerald; Sleutel, Steven; De Neve, Stefaan

    2016-05-15

    We evaluated trends (2005-2013) and patterns of dissolved organic nitrogen (DON) and its ratio with dissolved organic carbon (DOC), DOC:DON in atmospheric deposition and soil solution of five Level II plots of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) in Flanders, Northern Belgium. The primary aim was to confirm positive postulated trends in DON levels and DOC:DON under on-going recovery from acidification. The DON concentrations (0.95-1.41 mg L(-1)) and fluxes (5.6-8.3 kg ha(-1)y(-1)) in throughfall were about twice as high compared to precipitation in the open field (0.40-0.48 mg L(-1), 3.0-3.9 kg ha(-1)y(-1)). Annual soil profile leaching losses of DON varied between 1.2 and 3.7 kg ha(-1)y(-1). The highest soil DON concentrations and fluxes were observed beneath the O horizon (1.84-2.36 mg L(-1), 10.1-12.3 kg ha(-1)y(-1)). Soil solution concentrations and fluxes of DON showed significant increasing trends. Temporarily soil solution DOC:DON rose following an exceptionally long spring drought in 2007, suggesting an effect of drying and rewetting on DOM composition. Further research is needed to test the dependence of DON and DOC:DON on factors such as latitude, forest cover, length of the growing season, hydrology and topography. Nonetheless, even with considerable variation in soil type, level of base saturation, and soil texture in the five included ICP Forests Level II plots, all data revealed a proportionally larger positive response of DON flux than DOC to recovery from acidification.

  2. Global transcriptional responses of the toxic cyanobacterium, Microcystis aeruginosa, to nitrogen stress, phosphorus stress, and growth on organic matter.

    Directory of Open Access Journals (Sweden)

    Matthew J Harke

    Full Text Available Whole transcriptome shotgun sequencing (RNA-seq was used to assess the transcriptomic response of the toxic cyanobacterium Microcystis aeruginosa during growth with low levels of dissolved inorganic nitrogen (low N, low levels of dissolved inorganic phosphorus (low P, and in the presence of high levels of high molecular weight dissolved organic matter (HMWDOM. Under low N, one third of the genome was differentially expressed, with significant increases in transcripts observed among genes within the nir operon, urea transport genes (urtBCDE, and amino acid transporters while significant decreases in transcripts were observed in genes related to photosynthesis. There was also a significant decrease in the transcription of the microcystin synthetase gene set under low N and a significant decrease in microcystin content per Microcystis cell demonstrating that N supply influences cellular toxicity. Under low P, 27% of the genome was differentially expressed. The Pho regulon was induced leading to large increases in transcript levels of the alkaline phosphatase phoX, the Pst transport system (pstABC, and the sphX gene, and transcripts of multiple sulfate transporter were also significantly more abundant. While the transcriptional response to growth on HMWDOM was smaller (5-22% of genes differentially expressed, transcripts of multiple genes specifically associated with the transport and degradation of organic compounds were significantly more abundant within HMWDOM treatments and thus may be recruited by Microcystis to utilize these substrates. Collectively, these findings provide a comprehensive understanding of the nutritional physiology of this toxic, bloom-forming cyanobacterium and the role of N in controlling microcystin synthesis.

  3. Global transcriptional responses of the toxic cyanobacterium, Microcystis aeruginosa, to nitrogen stress, phosphorus stress, and growth on organic matter.

    Science.gov (United States)

    Harke, Matthew J; Gobler, Christopher J

    2013-01-01

    Whole transcriptome shotgun sequencing (RNA-seq) was used to assess the transcriptomic response of the toxic cyanobacterium Microcystis aeruginosa during growth with low levels of dissolved inorganic nitrogen (low N), low levels of dissolved inorganic phosphorus (low P), and in the presence of high levels of high molecular weight dissolved organic matter (HMWDOM). Under low N, one third of the genome was differentially expressed, with significant increases in transcripts observed among genes within the nir operon, urea transport genes (urtBCDE), and amino acid transporters while significant decreases in transcripts were observed in genes related to photosynthesis. There was also a significant decrease in the transcription of the microcystin synthetase gene set under low N and a significant decrease in microcystin content per Microcystis cell demonstrating that N supply influences cellular toxicity. Under low P, 27% of the genome was differentially expressed. The Pho regulon was induced leading to large increases in transcript levels of the alkaline phosphatase phoX, the Pst transport system (pstABC), and the sphX gene, and transcripts of multiple sulfate transporter were also significantly more abundant. While the transcriptional response to growth on HMWDOM was smaller (5-22% of genes differentially expressed), transcripts of multiple genes specifically associated with the transport and degradation of organic compounds were significantly more abundant within HMWDOM treatments and thus may be recruited by Microcystis to utilize these substrates. Collectively, these findings provide a comprehensive understanding of the nutritional physiology of this toxic, bloom-forming cyanobacterium and the role of N in controlling microcystin synthesis.

  4. Biodegradability of dissolved organic carbon in the Yukon River and its tributaries: Seasonality and importance of inorganic nitrogen

    Science.gov (United States)

    Wickland, Kimberly P.; Aiken, George R.; Butler, Kenna; Dornblaser, Mark M.; RGM Spencer,; Striegl, Rob

    2012-01-01

    Northern high-latitude rivers transport large amounts of terrestrially derived dissolved organic matter (DOM) from boreal and arctic ecosystems to coastal areas and oceans. Current knowledge of the biodegradability of DOM in these rivers is limited, particularly for large rivers discharging to the Arctic Ocean. We conducted a seasonally comprehensive study of biodegradable dissolved organic carbon (BDOC) dynamics in the Yukon River and two of its tributaries in Alaska, USA. Distinct seasonal patterns of BDOC, consistent across a wide range of watershed size, indicate BDOC is transported year-round. Relative biodegradability (%BDOC) was greatest during winter, and decreased into spring and summer. Due to large seasonal differences in DOC concentration, the greatest concentrations of BDOC (mg C L−1) occurred during spring freshet, followed by winter and summer. While chemical composition of DOM was an important driver of BDOC, the overriding control of BDOC was mineral nutrient availability due to wide shifts in carbon (C) and nitrogen (N) stoichiometry across seasons. We calculated seasonal and annual loads of BDOC exported by the Yukon River by applying measured BDOC concentrations to daily water discharge values, and also by applying an empirical correlation between %BDOC and the ratio of DOC to dissolved inorganic N (DIN) to total DOC loads. The Yukon River exports ∼0.2 Tg C yr−1 as BDOC that is decomposable within 28 days. This corresponds to 12–18% of the total annual DOC export. Furthermore, we calculate that the six largest arctic rivers, including the Yukon River, collectively export ∼2.3 Tg C yr−1 as BDOC to the Arctic Ocean.

  5. Response of oxidative enzyme activities to nitrogen deposition affects soil concentrations of dissolved organic carbon

    Science.gov (United States)

    Waldrop, M.P.; Zak, D.R.

    2006-01-01

    Recent evidence suggests that atmospheric nitrate (NO3- ) deposition can alter soil carbon (C) storage by directly affecting the activity of lignin-degrading soil fungi. In a laboratory experiment, we studied the direct influence of increasing soil NO 3- concentration on microbial C cycling in three different ecosystems: black oak-white oak (BOWO), sugar maple-red oak (SMRO), and sugar maple-basswood (SMBW). These ecosystems span a broad range of litter biochemistry and recalcitrance; the BOWO ecosystem contains the highest litter lignin content, SMRO had intermediate lignin content, and SMBW leaf litter has the lowest lignin content. We hypothesized that increasing soil solution NO 3- would reduce lignolytic activity in the BOWO ecosystem, due to a high abundance of white-rot fungi and lignin-rich leaf litter. Due to the low lignin content of litter in the SMBW, we further reasoned that the NO3- repression of lignolytic activity would be less dramatic due to a lower relative abundance of white-rot basidiomycetes; the response in the SMRO ecosystem should be intermediate. We increased soil solution NO3- concentrations in a 73-day laboratory incubation and measured microbial respiration and soil solution dissolved organic carbon (DOC) and phenolics concentrations. At the end of the incubation, we measured the activity of ??-glucosidase, N-acetyl-glucosaminidase, phenol oxidase, and peroxidase, which are extracellular enzymes involved with cellulose and lignin degradation. We quantified the fungal biomass, and we also used fungal ribosomal intergenic spacer analysis (RISA) to gain insight into fungal community composition. In the BOWO ecosystem, increasing NO 3- significantly decreased oxidative enzyme activities (-30% to -54%) and increased DOC (+32% upper limit) and phenolic (+77% upper limit) concentrations. In the SMRO ecosystem, we observed a significant decrease in phenol oxidase activity (-73% lower limit) and an increase in soluble phenolic concentrations

  6. Agronomic performance and chemical response of sunflower (Helianthus annuus L. to some organic nitrogen sources and conventional nitrogen fertilizers under sandy soil conditions

    Directory of Open Access Journals (Sweden)

    Ramadan, Mohamed Fawzy

    2009-03-01

    Full Text Available Sunflower (Helianthus annuus L. is an option for oilseed production, particularly in dry land areas due to good root system development. In this study, two field experiments were performed in the El-Khattara region (Sharkia Governorate, Egypt during the 2005 season. The objective of this research was to determine the effect of organicnitrogen (ON sources and their combinations as well as to compare the effect of ON and ammonium sulfate (AS as a conventional fertilizer added individually or in combination on growth, yield components, oil percentage and the uptake of some macronutrients by sunflowers grown on sandy soil. The treatments of chicken manure (CM and a mixture of farmyard manure (FYM with CM were superior to the other treatments and gave the highest yield, dry matter yield, NPK uptake by plants at all growth stages along with seed yield at the mature stage. The effect of the different ON on crop yield and its components may follow the order; CM> palma residues (PR> FYM. This was more emphasized when the materials were mixed with AS at a ratio of 3:1 and 1:1. The uptake of nitrogen (N, phosphorus (P and potassium (K by plants was affected by the addition of different N sources and treatments. The highest nutrient content and uptake by straw were obtained when treated with CM followed by PR at all growth stages, while it was PR followed by CM for seeds. Oil recovery was shown to respond to the N supply and the changes in individual fatty acids were not statistically different. However, it seems that the application of organic fertilizers resulted in an increase in total unsaturated fatty acids compared to the control.El girasol (Helianthus annuus es una opción para la producción de semillas oleaginosas, en particular en terrenos arenosos debido al buen desarrollo de sus raíces. En este trabajo, dos estudios de campo fueron realizados en la región de El-Ishattara (Sharkia Governorate, Egypt durante la estación 2005. El efecto de

  7. Dinitrogen fixation and dissolved organic nitrogen fueled primary production and particulate export during the VAHINE mesocosm experiment (New Caledonia lagoon)

    Science.gov (United States)

    Berthelot, H.; Moutin, T.; L'Helguen, S.; Leblanc, K.; Hélias, S.; Grosso, O.; Leblond, N.; Charrière, B.; Bonnet, S.

    2015-07-01

    In the oligotrophic ocean characterized by nitrate (NO3-) depletion in surface waters, dinitrogen (N2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. In this study, we deployed large in situ mesocosms in New Caledonia in order to investigate (1) the contribution of N2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON), i.e., whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (PO43-) in order to prevent phosphorus (P) limitation and promote N2 fixation. The diazotrophic community was dominated by diatom-diazotroph associations (DDAs) during the first part of the experiment for 10 days (P1) followed by the unicellular N2-fixing cyanobacteria UCYN-C for the last 9 days (P2) of the experiment. N2 fixation rates averaged 9.8 ± 4.0 and 27.7 ± 8.6 nmol L-1 d-1 during P1 and P2, respectively. NO3- concentrations ( 0.05) during P1 (9.0 ± 3.3 %) and P2 (12.6 ± 6.1 %). However, the e ratio that quantifies the efficiency of a system to export particulate organic carbon (POCexport) compared to PP (e ratio = POCexport/PP) was significantly higher (p efficient at promoting C export than the production sustained by DDAs. During P1, PON was stable and the total amount of N provided by N2 fixation (0.10 ± 0.02 μmol L-1) was not significantly different (p > 0.05) from the total amount of PON exported (0.10 ± 0.04 μmol L-1), suggesting a rapid and probably direct export of the recently fixed N2 by the DDAs. During P2, both PON concentrations and PON export increased in the mesocosms by a factor 1.5-2. Unlike in P1, this PON production was not totally explained by the new N provided by N2 fixation. The use of DON, whose concentrations decreased significantly (p < 0.05) from 5.3 ± 0.5 μmol L-1 to 4.4 ± 0.5 μmol L-1, appeared to

  8. Carbon and nitrogen isotopes analysis and sources of organic matter in surface sediments from the Sanggou Bay and its adjacent areas, China

    Institute of Scientific and Technical Information of China (English)

    XIA Bin; CUI Yi; CHEN Bijuan; CUI Zhengguo; QU Keming; MA Feifei

    2014-01-01

    Naturally existing stable carbon and nitrogen isotopes are important in the study of sedimentary organic matter sources. To identify the sources of sedimentary organic matter in Sanggou Bay and its adjacent areas, which is characterized by high-density shellfish and seaweed aquaculture, the grain size, organic carbon (OC), total nitrogen (TN), carbon and nitrogen isotopic composition (δ13C andδ15N) of organic matter in the surface sediment were determined. The results showed that, in August, sedimentary OC and TN ranged from 0.17% to 0.76% and 0.04% to 0.14%, respectively. In November, OC and TN ranged from 0.23% to 0.87% and 0.05% to 0.14%, respectively. There was a significant positive correlation between OC and TN (R=0.98, P<0.0001), indicating that OC and TN were homologous. In August, theδ13C andδ15N of organic matter varied from −23.06‰ to −21.59‰ and 5.10‰ to 6.31‰, respectively. In November,δ13C andδ15N ranged from −22.87‰ to −21.34‰ and 5.13‰ to 7.31‰, respectively. This study found that the major sources of sedimentary organic matter were marine shellfish biodeposition, seaweed farming, and soil organic matter. Using a three-end-member mixed model, we estimated that the dominant source of sedimentary organic matter was shellfish biodeposition, with an average contribution rate of 65.53% in August and 43.00% in November. Thus, shellfish farming had a significant influence on the coastal carbon cycle.

  9. Long-term combined chemical and manure fertilizations increase soil organic carbon and total nitrogen in aggregate fractions at three typical cropland soils in China.

    Science.gov (United States)

    He, Y T; Zhang, W J; Xu, M G; Tong, X G; Sun, F X; Wang, J Z; Huang, S M; Zhu, P; He, X H

    2015-11-01

    Soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC) and nitrogen (MBN) are important factors of soil fertility. However, effects of the combined chemical fertilizer and organic manure or straw on these factors and their relationships are less addressed under long-term fertilizations. This study addressed changes in SOC, TN, MBC and MBN at 0-20 cm soil depth under three 17 years (September 1990-September 2007) long-term fertilization croplands along a heat and water gradient in China. Four soil physical fractions (coarse free and fine free particulate organic C, cfPOC and ffPOC; intra-microaggregate POC, iPOC; and mineral associated organic C, MOC) were examined under five fertilizations: unfertilized control, chemical nitrogen (N), phosphorus (P) and potassium (K) (NPK), NPK plus straw (NPKS, hereafter straw return), and NPK plus manure (NPKM and 1.5NPKM, hereafter manure). Compared with Control, manure significantly increased all tested parameters. SOC and TN in fractions distributed as MOC > iPOC > cfPOC > ffPOC with the highest increase in cfPOC (329.3%) and cfPTN (431.1%), and the lowest in MOC (40.8%) and MTN (45.4%) under manure. SOC significantly positively correlated with MBC, cfPOC, ffPOC, iPOC and MOC (R(2) = 0.51-0.84, P fertilization for improving soil fertility while straw return should take into account climate factors in Chinese croplands.

  10. Organic carbon and nitrogen isotopes in surface sediments from the western Arctic Ocean and their implications for sedimentary environments

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhihua; SHI Xuefa; CAI Deling; HAN Yibing; YANG Zuosheng

    2006-01-01

    Surface sediments from the Chukchi Sea and adjacent arctic deep sea were investigated for organic carbon and nitrogen isotopes (in δ13Corg and δ15Norg) as well as biogenic silica (BSiO2). δ13Corg and δ15Norg values of surface sediments in the study area fall between the end-member values of marine and terrestrial organic matter from the surrounding lands and seas, their variations reflect the changes of marine productivity and terrestrial supply in the study area. BSiO2 shows a similar distribution pattern with δ13Corg and δ15Norg, and can be used as an indicator of marine productivity. In the central-west Chukchi Sea and the Chukchi Rise, sediments have higher δ13Corg, δ15Norg and BSiO2 values, indicating the region has high marine productivity influenced by the nutrient-rich branches of the Pacific waters. In the coastal zone off northwestern Alaska, δ13Corg and δ15Norg values become lighter, indicating a weakening marine productivity and an increasing terrigenous supply due to the effects of the least nutrient-rich branch of the Pacific waters. In the north and the northeast of the study area (including the Chukchi Plateau, the Canada Basin and the Beaufort shelf), δ13Corg, δ15Norg and BSiO2 have the lowest values, and the terrigenous organic matter becomes dominant in surface sediments because this region has the longest ice-covered duration, the least nutrient-rich seawater and the increasing supply of terrestrial materials from the Mackenzie River and the northern Alaska under the action of the clockwise Beaufort gyre. Because the subarctic Pacific waters are continuously discharged into the central basin of the Arctic Ocean through the study area, the nutrient pool in the Chukchi Sea can be considered as a typical open system, the ratio of δ15N to BSiO2 content show some tracers that the level of nutrient utilization is contrary to nutrient supply and marine productivity formed in seawater.

  11. Removing organic and nitrogen content from a highly saline municipal wastewater reverse osmosis concentrate by UV/H2O2-BAC treatment.

    Science.gov (United States)

    Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A

    2015-10-01

    Reverse osmosis (RO) concentrate (ROC) streams generated from RO-based municipal wastewater reclamation processes pose potential health and environmental risks on their disposal to confined water bodies such as bays. A UV/H2O2 advanced oxidation process followed by a biological activated carbon (BAC) treatment was evaluated at lab-scale for the removal of organic and nutrient content from a highly saline ROC (TDS 16 g L(-1), EC 23.5 mS cm(-1)) for its safe disposal to the receiving environment. Over the 230-day operation of the UV/H2O2-BAC process, the colour and UV absorbance (254 nm) of the ROC were reduced to well below those of the influent to the reclamation process. The concentrations of DOC and total nitrogen (TN) were reduced by approximately 60% at an empty bed contact time (EBCT) of 60 min. The reduction in ammonia nitrogen by the BAC remained high under all conditions tested (>90%). Further investigation confirmed that the presence of residual peroxide in the UV/H2O2 treated ROC was beneficial for DOC removal, but markedly inhibited the activities of the nitrifying bacteria (i.e., nitrite oxidising bacteria) in the BAC system and hence compromised total nitrogen removal. This work demonstrated that the BAC treatment could be acclimated to the very high salinity environment, and could be used as a robust method for the removal of organic matter and nitrogen from the pre-oxidised ROC under optimised conditions.

  12. Organics and nitrogen removal from textile auxiliaries wastewater with A{sup 2}O-MBR in a pilot-scale

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Faqian [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Sun, Bin [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Shanghai Electric Group Co. Ltd. Central Academe, Shanghai 200070 (China); Hu, Jian; He, Yangyang [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China); Wu, Weixiang, E-mail: weixiang@zju.edu.cn [Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310058 (China)

    2015-04-09

    Highlights: • A pilot-scale A{sup 2}O-MBR system treating textile auxiliaries wastewater was assessed. • Organic matter and recycle ratio strongly affected the performance of the system. • GC/MS analysis found some refractory organics in the MBR permeate. • Combination of organic foulants and inorganic compounds caused membrane fouling. - Abstract: The removal of organic compounds and nitrogen in an anaerobic–anoxic–aerobic membrane bioreactor process (A{sup 2}O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH{sub 4}{sup +}–N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH{sub 4}{sup +}–N and TN were 87%, 96% and 55%, respectively. Gas chromatograph–mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry.

  13. Stratification and Storage of Soil Organic Carbon and Nitrogen as Affected by Tillage Practices in the North China Plain.

    Science.gov (United States)

    Zhao, Xin; Xue, Jian-Fu; Zhang, Xiang-Qian; Kong, Fan-Lei; Chen, Fu; Lal, Rattan; Zhang, Hai-Lin

    2015-01-01

    Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NCP). Three tillage treatments, including no till (NT), rotary tillage (RT), and plow tillage (PT), were established in 2001 in Luancheng County, Hebei Province. The concentration, storage, and SR of SOC and soil total nitrogen (TN) were assessed in both the wheat and maize seasons. Compared with RT and PT, the mean SRs for all depth ratios of SOC under NT increased by 7.85% and 30.61% during the maize season, and by 14.67% and 30.91% during the wheat season, respectively. The SR of TN for 0-5:30-50 cm increased by 140%, 161%, and 161% in the maize season, and 266%, 154%, and 122% in the wheat season compared to the SR for 0-5:5-10 cm under NT, RT and PT, respectively. The data indicated that SOC and TN were both concentrated in the surface-soil layers (0-10 cm) under NT but were distributed relatively evenly through the soil profile under PT. Meanwhile, the storage of SOC and TN was higher under NT for the surface soil (0-10 cm) but was higher under PT for the deeper soil (30-50 cm). Furthermore, the storage of SOC and TN was significantly related to SR of SOC and TN along the whole soil profile (P<0.0001). Therefore, SR could be used to explain and indicate the changes in the storage of SOC and TN. Further, NT stratifies SOC and TN, enhances the topsoil SOC storage, and helps to improve SOC sequestration and soil quality.

  14. Stratification and Storage of Soil Organic Carbon and Nitrogen as Affected by Tillage Practices in the North China Plain

    Science.gov (United States)

    Zhang, Xiang-Qian; Kong, Fan-Lei; Chen, Fu; Lal, Rattan; Zhang, Hai-Lin

    2015-01-01

    Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NCP). Three tillage treatments, including no till (NT), rotary tillage (RT), and plow tillage (PT), were established in 2001 in Luancheng County, Hebei Province. The concentration, storage, and SR of SOC and soil total nitrogen (TN) were assessed in both the wheat and maize seasons. Compared with RT and PT, the mean SRs for all depth ratios of SOC under NT increased by 7.85% and 30.61% during the maize season, and by 14.67% and 30.91% during the wheat season, respectively. The SR of TN for 0–5:30–50 cm increased by 140%, 161%, and 161% in the maize season, and 266%, 154%, and 122% in the wheat season compared to the SR for 0–5:5–10 cm under NT, RT and PT, respectively. The data indicated that SOC and TN were both concentrated in the surface-soil layers (0–10 cm) under NT but were distributed relatively evenly through the soil profile under PT. Meanwhile, the storage of SOC and TN was higher under NT for the surface soil (0–10 cm) but was higher under PT for the deeper soil (30–50 cm). Furthermore, the storage of SOC and TN was significantly related to SR of SOC and TN along the whole soil profile (P<0.0001). Therefore, SR could be used to explain and indicate the changes in the storage of SOC and TN. Further, NT stratifies SOC and TN, enhances the topsoil SOC storage, and helps to improve SOC sequestration and soil quality. PMID:26075391

  15. Diversity and Activity of Free-Living Nitrogen-Fixing Bacteria and Total Bacteria in Organic and Conventionally Managed Soils ▿ †

    OpenAIRE

    Orr, Caroline H.; James, Angela; Leifert, Carlo; Cooper, Julia M.; Cummings, Stephen P.

    2010-01-01

    Agricultural soils are heterogeneous environments in which conditions affecting microbial growth and diversity fluctuate widely in space and time. In this study, the molecular ecology of the total bacterial and free-living nitrogen-fixing communities in soils from the Nafferton Factorial Systems Comparison (NFSC) study in northeast England were examined. The field experiment was factorial in design, with organic versus conventional crop rotation, crop protection, and fertility management fact...

  16. Non-biased prediction of soil organic carbon and total nitrogen with vis-NIR spectroscopy, as affected by soil moisture content and texture

    OpenAIRE

    Kuang, Boyan Y.; Mouazen, Abdul Mounem

    2013-01-01

    This study was undertaken to evaluate the effects of moisture content (MC) and texture on the prediction of soil organic carbon (OC) and total nitrogen (TN) with visible and near infrared (vis-NIR) spectroscopy under laboratory and on-line measurement conditions. An AgroSpec spectrophotometer was used to develop calibration models of OC and TN using laboratory scanned spectra of fresh and processed soil samples collected from five fields on Silsoe Farm, UK. A previously developed on-line vis-...

  17. Geochemistry of organic carbon and nitrogen in surface sediments of coastal Bohai Bay inferred from their ratios and stable isotopic signatures.

    Science.gov (United States)

    Gao, Xuelu; Yang, Yuwei; Wang, Chuanyuan

    2012-06-01

    Total organic carbon (TOC), total nitrogen (TN) and their δ(13)C and δ(15)N values were determined for 42 surface sediments from coastal Bohai Bay in order to determine the concentration and identify the source of organic matter. The sampling sites covered both the marine region of coastal Bohai Bay and the major rivers it connects with. More abundant TOC and TN in sediments from rivers than from the marine region reflect the situation that most of the terrestrial organic matter is deposited before it meets the sea. The spatial variation in δ(13)C and δ(15)N signatures implies that the input of organic matter from anthropogenic activities has a more significant influence on its distribution than that from natural processes. Taking the area as a whole, surface sediments in the marine region of coastal Bohai Bay are dominated by marine derived organic carbon, which on average accounts for 62±11% of TOC.

  18. Removal of organic matters and nitrogenous pollutants simultaneously from two different wastewaters using biocathode microbial fuel cell.

    Science.gov (United States)

    Sevda, Surajbhan; Sreekrishnan, T R

    2014-09-19

    In this study, a dual chamber MFC was constructed for simultaneous removal of organic matter and nitrogenous pollutants and bioelectricity generation from synthetic and complex industrial wastewaters and it was operated in batch and continuous mode. When the cell potential was stable after 16 days of batch mode operation, the MFC was converted to continuous mode (from batch mode) and operated for 125 days with different organic loading rates (OLR) and ammonia loading rates (ALR) and fixed hydraulic retention time (HRT) of 40 h. The OLR of 1.49 kg COD m(-3) d(-1) and ALR of 0.58 kg NH3(-) m(-3) d(-1), for anodic and cathodic chambers, respectively, gave the best results. The highest value of cell potential on these OLRs was 310 mV with current density of 85.11 mA m(-2), power density of 26.38 mW m(-2) and volumetric power density of 192.20 mW m(-3). During this period, COD reduction was 78-83% in the anodic chamber and the ammonia reduction was 36-38%. After stable operation with synthetic wastewater one case study was performed with complex industrial wastewater. Continuous mode operation was performed at two different OLR and HRT with a constant ALR. A stable power density and volumetric power density of 23.56 mW m(-2) and 112.50 mW m(-3), respectively were achieved after 24 days of continuous operation at an OLR of 0.35 kg COD/m(3) day with an ALR of 0.43 kg NH3(-) m(-3) day(-1) and corresponding HRT of 68 h. A maximum of 89% COD removal and 40% removal of ammonia was obtained after 50 days. A stable voltage of 300 mV was obtained across 1000 Ω resistance. These findings suggest that BMFC can be used for the treatment of industrial wastewater, with carbon removal in anodic chamber and electricity generation.

  19. Dissolved organic carbon and nitrogen in precipitation, throughfall and stemflow from Schima superba and Cunninghamia lanceolata plantations in subtropical China

    Institute of Scientific and Technical Information of China (English)

    GUO Jian-fen; YANG Yu-sheng; CHEN Guang-shui; LIN Peng

    2005-01-01

    Despite growing attention to the role of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in forest nutrient cycling, their monthly concentration dynamics in forest ecosystems, especially in subtropical forests only were little known. The goal of this study is to measure the concentrations and monthly dynamics of DOC and DON in precipitation, throughfall and stemflow for two plantations of Schima superba (SS) and Chinese fir (Cunninghamia lanceolata, CF) in Jianou, Fujian, China. Samples of precipitation, throughfall and stemflow were collected on a rain event base from January 2002 to December 2002. Upon collection, all water samples were analyzed for DOC, NO3--N, NH4+-N and total dissolved N (TDN). DON was calculated by subtracting NO3--N and NH4+-N from TDN. The results showed that the precipitation had a mean DOC concentration of 1.7 mg·L-1 and DON concentration of 0.13 mg·L-1. The mean DOC and DON concentrations in throughfall were 11.2 and 0.24 mg·L-1 in the SS and 10.3 and 0.19 mg·L-1 in the CF respectively. Stemflow DOC and DON concentrations in the CF (19.1 and 0.66 mg·L-1 respectively) were significantly higher than those in the SS (17.6 and 0.48 mg·L-1 respectively). No clear monthly variation in precipitation DOC concentration was found in our study, while DON concentration in precipitation tended to be higher in summer or autumn. The monthly variations of DON concentrations were very similar in throughfall and stemflow at both forests, showing an increase at the beginning of the rainy season in March. In contrast, monthly changes of the DOC concentrations in throughfall of the SS and CF were different to those in stemflow. Throughfall DOC concentrations were higher from February to April, while relatively higher DOC concentrations in stemflow were found during September-November period.

  20. Effect of Rotational Tillage on Soil Aggregates, Organic Carbon and Nitrogen in the Loess Plateau Area of China

    Institute of Scientific and Technical Information of China (English)

    HOU Xian-Qing; LI Rong; JIA Zhi-Kuan; HAN Qing-Fang

    2013-01-01

    In rain-fed semi-arid agroecosystems,continuous conventional tillage can cause serious problems in soil quality and crop production,whereas rotational tillage (no-tillage and subsoiling) could decrease soil bulk density,and increase soil aggregates and organic carbon in the 0-40 cm soil layer.A 3-year field study was conducted to determine the effect of tillage practices on soil organic carbon (SOC),total nitrogen (TN),water-stable aggregate size distribution and aggregate C and N sequestration from 0 to 40 cm soil in semi-arid areas of southern Ningxia.Three tillage treatments were tested:no-tillage in year 1,subsoiling in year 2,and no-tillage in year 3 (NT-ST-NT); subsoiling in year 1,no-tillage in year 2,and subsoiling in year 3 (ST-NT-ST); and conventional tillage over years 1-3 (CT).Mean values of soil bulk density in 0-40 cm under NT-ST-NT and ST-NT-ST were significantly decreased by 3.3% and 6.5%,respectively,compared with CT,while soil total porosity was greatly improved.Rotational tillage increased SOC,TN,and water-stable aggregates in the 0-40 cm soil,with the greatest effect under ST-NT-ST.In 0-20 and 20-40 cm soils,the tillage effect was confined to the 2-0.25 mm size fraction of soil aggregates,and rotational tillage treatments obtained significantly higher SOC and TN contents than conventional tillage.No significant differences were detected in SOC and TN contents in the > 2 mm and < 0.25 mm aggregates among all treatments.In conclusion,rotational tillage practices could significantly increase SOC and TN levels,due to a fundamental change in soil structure,and maintain agroecosystem sustainability in the Loess Plateau area of China.

  1. Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

    Directory of Open Access Journals (Sweden)

    D. Obrist

    2009-05-01

    Full Text Available This study presents data on mercury (Hg concentrations, stochiometric relations to carbon (C and nitrogen (N, and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94–98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leavesr2=0.58 and N and C (r2=0.64 in decomposing litter, but a positive correlation between litter Hg and N (r2=0.70. These inverse relations may reflect preferential retention of N and Hg over C during decomposition, or may be due to older age of decomposed litter layers which are exposed to longer-term atmospheric Hg deposition in the field. The results indicate that litter Hg levels depend on decomposition stage and may not follow generally observed positive relationships between Hg and organic C.

    Mineral soil layers show strong positive correlations of Hg to C across all sites and soil horizons (r2=0.83, but Hg concentrations are even more closely related to N with a similar slope to that observed in litter (r2=0.92. Soil N levels alone explain over 90% of Hg pool sizes across the four Sierra Nevada forest sites. This suggests that soil organic N and C groups provide sorption sites for Hg to retain atmospheric deposition. However, the patterns could be due to indirect relationships where high soil N and C levels reflect high ecosystem productivity which leads to corresponding high atmospheric Hg deposition inputs via leaf litterfall and plant senescence. Our results also show that two of the sites previously affected by

  2. Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

    Directory of Open Access Journals (Sweden)

    D. Obrist

    2009-02-01

    Full Text Available This study presents data on Hg concentrations, stochiometric relations to carbon (C and nitrogen (N, and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94–98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leaves < Dry Needles/Leaves < Oi litter < Oe litter < Oa litter. Stochiometric relations show negative correlations between Hg and C (r2=0.58 and N and C (r2=0.64 in decomposing litter, but a positive correlation between litter Hg and N (r2=0.70. These inverse relations may reflect preferential retention of N and Hg over C during decomposition, or may be due to older age of decomposed litter layers which are exposed to longer-term atmospheric Hg deposition in the field. The results indicate that litter Hg levels depend on decomposition stage and may not follow generally observed positive relationships between Hg and organic C.

    Mineral soil layers show strong positive correlations of Hg to C across all sites and soil horizons (r2=0.83, but Hg concentrations are even more closely related to N with a similar slope to that observed in litter (r2=92%. Soil N levels alone explain over 90% of Hg pool sizes across the four Sierra Nevada forest sites. This suggest that soil organic N and C groups provide sorption sites for Hg to retain atmospheric deposition. However, the patterns could be due indirect relationships where high soil N and C levels reflect high ecosystem productivity which leads to corresponding high atmospheric Hg deposition inputs via leaf litterfall and plant senescence. Our results also show that two of the sites previously affected by

  3. Enhanced organics and nitrogen removal in batch-operated vertical flow constructed wetlands by combination of intermittent aeration and step feeding strategy.

    Science.gov (United States)

    Fan, Jinlin; Liang, Shuang; Zhang, Bo; Zhang, Jian

    2013-04-01

    Oxygen and carbon source supply are usually insufficient in subsurface flow constructed wetlands. Simultaneous removal of organic pollutants and nitrogen in five batch-operated vertical flow constructed wetlands under different operating conditions was investigated. Alternate aerobic and anaerobic regions were created well with intermittent aeration. Four-month experiments showed that the wetland-applied intermittent aeration combined with step feeding strategy (reactor E) greatly improved the removal of organics, ammonium nitrogen (NH4-N), and total nitrogen (TN) simultaneously, which were 97, 96, and 82%, respectively. It was much better than non-aerated reactors A and B and outperformed intermittently aerated reactor D without step feeding. Continuous aeration (reactor C) significantly enhanced the organics removal and nitrification, but it limited the TN removal (29%) seriously as a result of low denitrification level, and the high operation cost remained a question. The effect of plants was confirmed in this study, and the monitoring data showed that the plants could grow normally. Intermittent aeration as well as step feeding had no obvious influence on the growth of wetland plants in this study.

  4. Use of stable isotopes of carbon and nitrogen to identify sources of organic matter to bed sediments of the Tualatin River, Oregon

    Science.gov (United States)

    Bonn, Bernadine A.; Rounds, Stewart A.

    2010-01-01

    The potential sources of organic matter to bed sediment of the Tualatin River in northwestern Oregon were investigated by comparing the isotopic fractionation of carbon and nitrogen and the carbon/nitrogen ratios of potential sources and bed sediments. Samples of bed sediment, suspended sediment, and seston, as well as potential source materials, such as soil, plant litter, duckweed, and wastewater treatment facility effluent particulate were collected in 1998-2000. Based on the isotopic data, terrestrial plants and soils were determined to be the most likely sources of organic material to Tualatin River bed sediments. The delta 13C fractionation matched well, and although the delta 15N and carbon/nitrogen ratio of fresh plant litter did not match those of bed sediments, the changes expected with decomposition would result in a good match. The fact that the isotopic composition of decomposed terrestrial plant material closely resembled that of soils and bed sediments supports this conclusion. Phytoplankton probably was not a major source of organic matter to bed sediments. Compared to the values for bed sediments, the delta 13C values and carbon/nitrogen ratios of phytoplankton were too low and the delta 15N values were too high. Decomposition would only exacerbate these differences. Although phytoplankton cannot be considered a major source of organic material to bed sediment, a few bed sediment samples in the lower reach of the river showed a small influence from phytoplankton as evidenced by lower delta 13C values than in other bed sediment samples. Isotopic data and carbon/nitrogen ratios for bed sediments generally were similar throughout the basin, supporting the idea of a widespread source such as terrestrial material. The delta 15N was slightly lower in tributaries and in the upper reaches of the river. Higher rates of sediment oxygen demand have been measured in the tributaries in previous studies and coupled with the isotopic data may indicate the

  5. Effect of temperature and pH on the kinetics of methane production, organic nitrogen and phosphorus removal in the batch anaerobic digestion process of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, E. [Consultores Ambientales (CONAM), Havanna (Cuba); Borja, R. [Instituto de la Grasa (C.S.I.C.)., Sevilla (Spain); Weiland, P. [Institute of Technology, Federal Research Center of Agriculture (FAL), Braunschweig (Germany); Travieso, L. [Departamento de Estudios sobre Contaminacion Ambiental (DECA-CNIC), Centro Nacional de Investigaciones Cientificas (CNIC), La Habana (Cuba); Martin, A. [Departamento de Ingenieria Quimica, Facultad de Ciencias, Cordoba (Spain)

    2000-03-01

    A study of the effect of temperature and pH on the kinetics of methane production and organic nitrogen and phosphorus degradation in the anaerobic digestion process of cattle manure was carried out. Two laboratory-scale batch completely mixed reactors, operating at 35 C (mesophilic temperature), and other two, operating at 60 C (thermophilic temperature) were used. For each temperature selected, the influent pH values were 7.6 (initial pH of the waste used) and 7.0. The apparent kinetic constants of the biomethanization process increased 2.3 times when the initial pH of the influent was increased from 7.0 to 7.6 at mesophilic temperature. The values found at thermophilic temperature were similar. The kinetic constants of methane production decreased 2.6 and 7.2 times when the operating temperature increased from 35 C to 60 C for the experiments carried out at initial pH of 7.0 and 7.6, respectively. The methane yield coefficient (l CH{sub 4} STP/g VS removed) also decreased when the temperature increased from 35 C to 60 C for the two initial pH values studied. This behaviour agreed with the major inhibition level observed at thermophilic temperature as a result of the higher organic nitrogen removal and ammonia nitrogen production observed at 60 C. Specifically, the specific rate constants for organic nitrogen removal and ammonia nitrogen production increased 3.6 and 12 times when the temperature was increased from 35 C to 60 C for the experiments carried out at initial pH values of 7.0 and 7.6, respectively. In the same way, the values of the kinetic constant for phosphorus removal were 44% and 80% higher than those obtained at 35 C for the two initial pH values above-mentioned, respectively. Finally, the experimental values of organic nitrogen and phosphorus concentrations were reproduced with deviations equal to or less than 10% and 15% in every case, respectively. (orig.)

  6. Invasive Community-Acquired Methicillin-Resistant Staphylococcus aureus in a Japanese Girl with Disseminating Multiple Organ Infection: A Case Report and Review of Japanese Pediatric Cases

    Directory of Open Access Journals (Sweden)

    Ryuta Yonezawa

    2015-01-01

    Full Text Available Pediatric invasive community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA infection is very serious and occasionally fatal. This infectious disease is still a relatively rare and unfamiliar infectious disease in Japan. We report a positive outcome in a 23-month-old Japanese girl with meningitis, osteomyelitis, fasciitis, necrotizing pneumonia, urinary tract infection, and bacteremia due to CA-MRSA treated with linezolid. PCR testing of the CA-MRSA strain was positive for PVL and staphylococcal enterotoxin b and negative for ACME. SCC mec was type IVa. This case underscores the selection of effective combinations of antimicrobial agents for its treatment. We need to be aware of invasive CA-MRSA infection, which rapidly progresses with a serious clinical course, because the incidence of the disease may be increasing in Japan.

  7. The effects of manure and nitrogen fertilizer applications on soil organic carbon and nitrogen in a high-input cropping system.

    Science.gov (United States)

    Ren, Tao; Wang, Jingguo; Chen, Qing; Zhang, Fusuo; Lu, Shuchang

    2014-01-01

    With the goal of improving N fertilizer management to maximize soil organic carbon (SOC) storage and minimize N losses in high-intensity cropping system, a 6-years greenhouse vegetable experiment was conducted from 2004 to 2010 in Shouguang, northern China. Treatment tested the effects of organic manure and N fertilizer on SOC, total N (TN) pool and annual apparent N losses. The results demonstrated that SOC and TN concentrations in the 0-10cm soil layer decreased significantly without organic manure and mineral N applications, primarily because of the decomposition of stable C. Increasing C inputs through wheat straw and chicken manure incorporation couldn't increase SOC pools over the 4 year duration of the experiment. In contrast to the organic manure treatment, the SOC and TN pools were not increased with the combination of organic manure and N fertilizer. However, the soil labile carbon fractions increased significantly when both chicken manure and N fertilizer were applied together. Additionally, lower optimized N fertilizer inputs did not decrease SOC and TN accumulation compared with conventional N applications. Despite the annual apparent N losses for the optimized N treatment were significantly lower than that for the conventional N treatment, the unchanged SOC over the past 6 years might limit N storage in the soil and more surplus N were lost to the environment. Consequently, optimized N fertilizer inputs according to root-zone N management did not influence the accumulation of SOC and TN in soil; but beneficial in reducing apparent N losses. N fertilizer management in a greenhouse cropping system should not only identify how to reduce N fertilizer input but should also be more attentive to improving soil fertility with better management of organic manure.

  8. Concentration, composition, bioavailability, and N-nitrosodimethylamine formation potential of particulate and dissolved organic nitrogen in wastewater effluents: A comparative study.

    Science.gov (United States)

    Hu, Haidong; Ma, Haijun; Ding, Lili; Geng, Jinju; Xu, Ke; Huang, Hui; Zhang, Yingying; Ren, Hongqiang

    2016-11-01

    Wastewater-derived organic nitrogen (org-N) can act as both nutrients and carcinogenic nitrogenous disinfection byproduct precursors. In this study, the concentration, composition, bioavailability, and N-nitrosodimethylamine (NDMA) formation potential of particulate organic nitrogen (PON) from three different municipal wastewater treatment plants were characterized and compared with that of effluent dissolved organic nitrogen (DON). The average effluent PON and DON concentrations ranged from 0.09 to 0.55mgN/L and from 0.91 to 1.88mgN/L, respectively. According to principal component analysis, org-N composition and characterization differed in PON and DON samples (n=20). Compared with DON, PON tended to be enriched in protein and nucleic acids, and showed a more proteinaceous character. Composition of org-N functional groups estimated from the X-ray photoelectron spectroscopy N 1s spectra indicate no significant differences in the molecular weight distribution of the protein-like materials between PON and DON. Moreover, PON exhibited a significantly higher bioavailability (61.0±13.3%) compared to DON (38.5±12.4%, p˂0.05, t-test) and a significantly higher NDMA yields (791.4±404.0ng/mg-N) compared to DON (374.8±62.5ng/mg-N, p˂0.05, t-test). Accordingly, PON contributed to approximately 12.3-41.7% of the total bioavailable org-N and 22.0-38.4% of the total NDMA precursors in wastewater effluents. Thus, the potential adverse effects of PON on wastewater discharge and reuse applications should not be overlooked, even though it only accounted for 7.4-26.8% of the total effluent org-N.

  9. Metabolism of organic acids, nitrogen and amino acids in chlorotic leaves of 'Honeycrisp' apple (Malus domestica Borkh) with excessive accumulation of carbohydrates.

    Science.gov (United States)

    Wang, Huicong; Ma, Fangfang; Cheng, Lailiang

    2010-07-01

    Metabolite profiles and activities of key enzymes in the metabolism of organic acids, nitrogen and amino acids were compared between chlorotic leaves and normal leaves of 'Honeycrisp' apple to understand how accumulation of non-structural carbohydrates affects the metabolism of organic acids, nitrogen and amino acids. Excessive accumulation of non-structural carbohydrates and much lower CO(2) assimilation were found in chlorotic leaves than in normal leaves, confirming feedback inhibition of photosynthesis in chlorotic leaves. Dark respiration and activities of several key enzymes in glycolysis and tricarboxylic acid (TCA) cycle, ATP-phosphofructokinase, pyruvate kinase, citrate synthase, aconitase and isocitrate dehydrogenase were significantly higher in chlorotic leaves than in normal leaves. However, concentrations of most organic acids including phosphoenolpyruvate (PEP), pyruvate, oxaloacetate, 2-oxoglutarate, malate and fumarate, and activities of key enzymes involved in the anapleurotic pathway including PEP carboxylase, NAD-malate dehydrogenase and NAD-malic enzyme were significantly lower in chlorotic leaves than in normal leaves. Concentrations of soluble proteins and most free amino acids were significantly lower in chlorotic leaves than in normal leaves. Activities of key enzymes in nitrogen assimilation and amino acid synthesis, including nitrate reductase, glutamine synthetase, ferredoxin and NADH-dependent glutamate synthase, and glutamate pyruvate transaminase were significantly lower in chlorotic leaves than in normal leaves. It was concluded that, in response to excessive accumulation of non-structural carbohydrates, glycolysis and TCA cycle were up-regulated to "consume" the excess carbon available, whereas the anapleurotic pathway, nitrogen assimilation and amino acid synthesis were down-regulated to reduce the overall rate of amino acid and protein synthesis.

  10. Sources and Cycling of Dissolved Organic Matter in the Sacramento - San Joaquin Delta, California, Using Carbon, Nitrogen, and Sulfur Isotopes

    Science.gov (United States)

    Silva, S. R.; Kendall, C.; Doctor, D. H.; Bergamaschi, B. A.; Fram, M. S.; Kraus, T.

    2006-12-01

    An important water quality concern of the Sacramento-San Joaquin Delta portion of the Calfed Bay-Delta restoration program is the generation of disinfection byproducts (DBP) as a result of chlorination or ozonation of San Francisco Bay Delta drinking water. One means of reducing DBPs is through monitoring and control of water sources from the various delta environments entering the California aqueduct with the objective of reducing the quantity of dissolved organic matter (DOM) and lowering the fraction with the highest DBP formation potential. The purpose of this study is to investigate the use of carbon, nitrogen, and sulfur isotopic compositions of DOM to help differentiate DOM sources and interpret seasonal variations. For this purpose, water samples collected from five general delta environments between December 1999 and June 2001 were analyzed for d13C, d15N, and d34S of DOM as well as for various chemical and optical properties. Monthly averages of d13C and d15N values for DOM retained on XAD-4 and XAD-8 resins show distinctive compositions for island drain and wetland environments throughout the year which reflect the agriculturally- related terrestrial sources of DOM from island drains, and the aquatic sources for the wetland areas. On average, the d13C values of DOM from open water (flooded island) environments, channels, and the Sacramento River water are indistinguishable from each other from spring through fall and show a progressive increase in d13C, which is likely controlled by the cycle of aquatic production through the growing season. The isotopic values from these environments diverge in the winter reflecting a change in the relative importance of the various mechanisms (sources and cycling) controlling DOM production. Sulfur isotopes show both the effects of sulfate reduction and the influence of seawater sulfate on local biota. The d13C, d15N, and d34S values show a number of correlations related to both environment and season, reflecting the

  11. Fate of bulk organic matter, nitrogen, and pharmaceutically active compounds in batch experiments simulating soil aquifer treatment (SAT) using primary effluent

    KAUST Repository

    Abel, Chol D T

    2013-06-30

    Reduction of bulk organic matter, nitrogen, and pharmaceutically active compounds from primary effluent during managed aquifer recharge was investigated using laboratory-scale batch reactors. Biologically stable batch reactors were spiked with different concentrations of sodium azide to inhibit biological activity and probe the effect of microbial activity on attenuation of various pollutants of concern. The experimental results obtained revealed that removal of dissolved organic carbon correlated with active microbial biomass. Furthermore, addition of 2 mM of sodium azide affected nitrite-oxidizing bacteria leading to accumulation of nitrite-nitrogen in the reactors while an ammonium-nitrogen reduction of 95.5 % was achieved. Removal efficiencies of the hydrophilic neutral compounds phenacetin, paracetamol, and caffeine were independent of the extent of the active microbial biomass and were >90 % in all reactors, whereas removal of pentoxifylline was dependent on the biological stability of the reactor. However, hydrophobic ionic compounds exhibited removal efficiency >80 % in batch reactors with the highest biological activity as evidenced by high concentration of adenosine triphosphate. © 2013 Springer Science+Business Media Dordrecht.

  12. Removal of organics and nutrients from food wastewater using combined thermophilic two-phase anaerobic digestion and shortcut biological nitrogen removal.

    Science.gov (United States)

    Cui, Fenghao; Lee, Seungho; Kim, Moonil

    2011-10-15

    A process combining pilot-scale two-phase anaerobic digestion and shortcut biological nitrogen removal (SBNR) was developed to treat organics and nutrients (nitrogen and phosphorus) from food wastewater. The thermophilic two-phase anaerobic digestion process was investigated without adjusting the pH of the wastewater for the pre-acidification process. The digested food wastewater was treated using the SBNR process without supplemental carbon sources or alkalinity. Under these circumstances, the combined system was able to remove about 99% of COD, 88% of TN, and 97% of TP. However, considerable amounts of nutrients were removed due to chemical precipitation processes between the anaerobic digestion and SBNR. The average TN removal efficiency of the SBNR process was about 74% at very low C/N (TCOD/TN) ratio of 2. The SBNR process removed about 39% of TP from the digested food wastewater. Conclusively, application of the combined system improved organic removal efficiency while producing valuable energy (biogas), removed nitrogen at a low C/N ratio, and conserved additional resources (carbon and alkalinity).

  13. [Characteristics of water-soluble organic nitrogen of PM2.5 in Xi'an during wintertime non-haze and haze periods].

    Science.gov (United States)

    Cheng, Yu-Ting; Wang, Ge-Hui; Sun, Tao; Cheng, Chun-Lei; Meng, Jing-Jing; Ren, Yan-Qin; Li, Jian-Jun

    2014-07-01

    High-volume PM2.5 samples were collected hourly from 4 December to 13 December 2012 at an urban site in Xi'an and analyzed for organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), water-soluble total nitrogen (WSTN), water-soluble organic nitrogen (WSON) and inorganic ions to investigate the sources and formation mechanism of WSON. The results showed that during the sampling period the averaged hourly concentration of WSON was (12 +/- 9.4) microg x m(-3) and maximized at 31 microg x m(-3), accounting for 47% +/- 9.8% of WSTN with NH4(+) -N and NO3(-) -N being 29% +/- 8.5% and 23% +/- 8.1%, respectively. WSON: WSOC (N: C) mass ratios ranged from 0.04 to 0.65 with an average of 0.31 +/- 0.13 during the observation period. WSON was (1.6 +/- 0.9) microg x m(-3), (6.5 +/- 3.9) microg x m(-3) and (23 +/- 4.7) microg x m(-3) in non-haze days (visibility > 10 km), light haze days (5 km haze days (visibility haze days to 0.3 +/- 0.1 on light haze days and 0.4 +/- 0.1 on heavy haze days, in consistence with the enhanced acidity of the fine particles. In addition, during the whole sampling period, WSON was strongly correlated with NH4(+), SO4(2-) and NO3(-) (R2 > 0.80), and negatively correlated with cation-anion equivalent ratio (R2 = 0.53). These phenomena can be mainly ascribed to a gas-particle conversion of gaseous water-soluble nitrogen-containing organic compounds like amines via acid-base reactions, which was sharply increased under the favorable meteorological conditions (e.g., low temperature and high humidity) during the heavy haze days.

  14. Yield and apparent dry matter and nitrogen balances for muskmelon in a long-term comparison between an organic and a conventional low input cropping system

    Directory of Open Access Journals (Sweden)

    Michela Farneselli

    2015-09-01

    Full Text Available Nine-year yields and apparent balances of dry matter and nitrogen (N are reported for muskmelon cultivated in a long-term comparison trial between an organic and a conventional low input system in Central Italy. In every year, yield, above ground biomass and N accumulation of each cash crop, green manure and weeds, and the partitioning between marketable yield and crop residues were determined. Apparent dry matter and nitrogen balances were calculated at the end of each crop cycle by taking into account the amounts of dry matter and ex novo N supplied to the system as green manure legume Ndfa (i.e., an estimate of N derived from the atmosphere via symbiotic fixation and fertilisers, and those removed with marketable yield. Differences between systems varied across years. On average, organic muskmelon yielded 16% less than the conventional one, while the fruit quality was similar in the two cropping systems. Fruit ripening began one week later and it was more scaled than in the crop grown conventionally. This was the consequence of a slow initial growth of the organic crop, due to inadequate green manure N total supply or timing of N release. Moreover such a wide spaced crop (0.5 plants m–2, in rows 2 m apart was not efficient in intercepting N released from green manure biomass incorporated broadcast. Compared to the conventional crop management, the organic crop management resulted in much higher organic matter supply to the soil and in higher residual N after harvest. Thus, the choice of cultivating wheat just after melon to prevent postharvest residual N loss appears a key strategy especially in organic systems. Fall-winter green manure crops contributed to the self-sufficiency of the organic system by supplying muskmelon with either N absorbed from the soil or ex novo legume Ndfa.

  15. Organic and Inorganic Nitrogen Impact Chlorella variabilis Productivity and Host Quality for Viral Production and Cell Lysis.

    Science.gov (United States)

    Cheng, Yu-Shen; Labavitch, John; VanderGheynst, Jean S

    2015-05-01

    Microalgae have been proposed as a potential feedstock for biofuel production; however, cell disruption is usually required for collection and utilization of cytoplasmic polysaccharides and lipids. Virus infection might be one approach to disrupt the cell wall. The concentration of yeast extract and presence of KNO3 in algae cultivation media were investigated to observe their effects on Chlorella variabilis NC64A physiology and composition and the subsequent effect on production of Chlorella virus and disruption of infected cells. Cytoplasmic starch accumulation increased from 5% to approximately 35% of the total dry weight when yeast extract decreased from 1 to 0.25 g L(-1). When cells were cultured with the lowest nitrogen levels, the total polysaccharide accounted for more than 50% of the cell wall, which was 1.7 times higher than the content in cells cultured with the highest nitrogen levels. The C/N ratio of the algal biomass decreased by a factor of approximately 2 when yeast extract increased from 0.25 to 1 g L(-1). After virus infection, cells with a low C/N ratio produced a 7.6 times higher burst size than cells with a high C/N ratio, suggesting that the nitrogen content in C. variabilis has a large influence on viral production and cell lysis. The results have implications on management of nitrogen for both the synthesis of products from algae and product recovery via viral lysis.

  16. Effects of soil organic matter and nitrogen supply on competition between Fectuca ovina and Deschampsia flexuosa during inland dune succession

    NARCIS (Netherlands)

    Mierlo, van J.E.M.; Wilms, Y.J.C.; Berendse, F.

    2000-01-01

    We tested the prediction that the successional replacement of plant species during succession on inland sand dunes results from the effects of an increase in nitrogen mineralization on competitive interactions. The growth and competitive strength of Festuca ovina and Deschampsia flexuosa on soil sub

  17. INFLUENCE OF ORGANIC AND MINERAL FERTILIZATION ON GERMINATION, LEAF NITROGEN, NITRATE ACCUMULATION AND YIELD OF VEGETABLE AMARANTH

    NARCIS (Netherlands)

    Kooten, Olaf van

    2012-01-01

    The influence of manure and diammonium phosphate (DAP) mineral fertilizer on germination, leaf nitrogen content, nitrate accumulation and yield of vegetable amaranth (Amaranthus hypochondriacus) was investigated. Field trials were set up at the University of Nairobi Field Station at the Upper Kabete

  18. Influence of organic and mineral fertilization on germination, leaf nitrogen, nitrate accumulation and yield of vegetable amaranth

    NARCIS (Netherlands)

    Onyango, Cecilia M.; Kooten, Olaf van

    2012-01-01

    The influence of manure and diammonium phosphate (DAP) mineral fertilizer on germination, leaf nitrogen content, nitrate accumulation and yield of vegetable amaranth (Amaranthus hypochondriacus) was investigated. Field trials were set up at the University of Nairobi Field Station at the Upper Kabete

  19. Acquired inflammatory demyelinating neuropathies.

    Science.gov (United States)

    Ensrud, E R; Krivickas, L S

    2001-05-01

    The acquired demyelinating neuropathies can be divided into those with an acute onset and course and those with a more chronic course. The acute neuropathies present as Guillain-Barré syndrome and include acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller Fisher syndrome, acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and acute pandysautonomia. The chronic neuropathies are collectively known as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and include MADSAM (multifocal acquired demyelinating sensory and motor neuropathy, also know as Lewis-Sumner syndrome) and DADS (distal acquired demyelinating symmetric neuropathy) as variants. The clinical features, pathology, pathogenesis, diagnosis, treatment, rehabilitation, and prognosis of these neuropathies are discussed.

  20. Effect of organic matter and soil fertility on nitrogen mineralization and its uptake by cassava (Manihot esculenta Crantz in a typic Hapludults

    Directory of Open Access Journals (Sweden)

    Andy Wijanarko

    2015-06-01

    Full Text Available Fertility of soil and crop biomass production are directly affected by organic matters present in soil. The availability of organic matter and its quality plays a key role in the soil, plants and environment sustainability. Present study was aimed to investigate the influence of organic matter and soil fertility on nitrogen mineralization and its uptake by cassava. To estimate the parameters of N mineralization potential (N0, rate of mineralization (k, and activation energy (Ea incubation experiments were conducted in the laboratory, using a first order equation. While the relationship between the parameters of N mineralization and nutrient uptake were carried o ut in green house pot experiments. Value of N0, k and Ea were reported 400 - 1156 mg/kg, 0.0056 - 0.098 per week and 10166 - 31478 J mol-1 respectively. N mineralization was positively correlat ed with water soluble N, N- Particulate Organic Matter, N microbial biomass, C- Particulate Organic Matter, C microbial biomass, N-total plant dry weight, N concentration and N uptake of cassava plants, however it was negatively correlated with C:N ratio. A higher N mineralization rate was found in soils with low C:N ratio of organic matter and higher fertility, as indicated by the value of N0, k and N0.k, which were higher than that of high C:N ratio of organic matter and low fertility of soil.

  1. 氮沉降影响下酸性森林土壤中水溶性有机氮的分布特征%DISTRIBUTION PATTERN OF WATER SOLUBLE ORGANIC NITROGEN IN ACIDIC FOREST SOILS RECEIVING NITROGEN DEPOSITION

    Institute of Scientific and Technical Information of China (English)

    郭景恒; 张逸; 何骞; 相秀娟

    2011-01-01

    选取贵州雷公山(LGS)和重庆铁山坪(TSP)两个氮沉降量具有明显差异的森林小流域,对土壤中水溶性有机氮(WSON)的分布特征进行了对比研究.在氮沉降较低的LGS流域土壤水中WSON占总氮的比例可达30%—60%,显著高于氮沉降高的TSP流域.TSP流域土壤浸提液中WSON的比例相较于土壤水有显著增加,说明该流域中WSON多附着于土壤表面,流动性较弱.在0—90 cm典型剖面内,TSP流域WSON的比例显著高于LGS流域.两剖面中WSON的比例均在中部(30—60 cm)达到最高值,分别为35.37%和5%Distribution pattern of water soluble organic nitrogen(WSON) in acidic forest soils was investigated in two selected catchments.In Leigongshan(LGS) catchment receiving lower nitrogen deposition,WSON was the important fraction of total dissolved nitrogen(TDN) in soil water,with the percentage ranging from 30% to 60%.However,the percentage was less than 10% in Teishanping(TSP) catchment receiving higher nitrogen deposition.In soil extracts of TSP catchment WSON percentage increased substantially,which indicates that WSON in this catchment mostly adsorbed on soil solid phase with low mobility.In the typical soil profiles(0—90 cm),WSON percentage in TSP catchment was significantly higher than that in LGS catchment.In LGS and TSP catchment,WSON percentage reached its maximum in the middle depth(30—60 cm) with the values of 35.37% and 55.82%,respectively.Vertical change of WSON was not synchronous with water soluble organic carbon(WSOC) in the investigated soil depth range.In the middle depth,C/N ratio of water soluble organic matter(WSOM) reached minimum.In the middle and bottom depth(30—90 cm),C/N ratio in TSP profile was significantly lower than in LGS profile,indicating higher nitrogen enrichment of WSOM in TSP catchment.

  2. Hospital-acquired pneumonia

    Science.gov (United States)

    ... tends to be more serious than other lung infections because: People in the hospital are often very sick and cannot fight off ... prevent pneumonia. Most hospitals have programs to prevent hospital-acquired infections.

  3. Acquired color vision deficiency.

    Science.gov (United States)

    Simunovic, Matthew P

    2016-01-01

    Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations.

  4. Laboratory-acquired brucellosis

    DEFF Research Database (Denmark)

    Fabiansen, C.; Knudsen, J.D.; Lebech, A.M.

    2008-01-01

    Brucellosis is a rare disease in Denmark. We describe one case of laboratory-acquired brucellosis from an index patient to a laboratory technician following exposure to an infected blood culture in a clinical microbiology laboratory Udgivelsesdato: 2008/6/9......Brucellosis is a rare disease in Denmark. We describe one case of laboratory-acquired brucellosis from an index patient to a laboratory technician following exposure to an infected blood culture in a clinical microbiology laboratory Udgivelsesdato: 2008/6/9...

  5. Impact of salinity on organic matter and nitrogen removal from a municipal wastewater RO concentrate using biologically activated carbon coupled with UV/H2O2.

    Science.gov (United States)

    Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A; Shahsavari, Esmaeil; Ball, Andrew S

    2016-05-01

    The concentrate streams generated from reverse osmosis (RO)-based municipal wastewater reclamation processes contain organic substances and nutrients at elevated concentrations, posing environmental and health risks on their disposal to confined receiving environments such as bays. The impact of salinity (TDS at 7, 10 and 16 g/L) of a RO concentrate (ROC) on the treatment efficiency of a biological activated carbon (BAC) system after pre-oxidation with UV/H2O2 was characterised in terms of removal of organic matter and nitrogen species, and the bacterial communities. Organic matter removal was comparable for the ROC over the tested salinity range, with 45-49% of DOC and 70-74% of UVA254 removed by the combined treatment. However, removal in total nitrogen (TN) was considerably higher for the ROC at the high salinity (TDS ∼ 16 mg/L) compared with the low (∼7 g/L) and medium salinity (∼10 g/L). Effective nitrification with high ammonium removal (>90%) was achieved at all salinity levels, whereas greater denitrification (39%) was obtained at high salinity than low (23%) and medium salinity (27%) which might suggest that the bacterial communities contributing to the greater denitrification were more halotolerant. Microbiological characterisation using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and culture based techniques showed that diversified bacterial communities were present in the BAC system as evident from different 16S rDNA. The major bacterial groups residing on the BAC media belonged to Bacillus (Firmicutes), Pseudomonas (γ-Proteobacteria), and Rhodococcus (Actinobacteria) for all salinity levels, confirming that these microbial communities could be responsible for carbon and nitrogen removal at the different salinity levels. This has implications in understanding the effectiveness and robustness of the BAC system over the salinity range of the ROC and so would be useful for optimising the treatment efficiency of

  6. Nursing home-acquired pneumonia.

    Science.gov (United States)

    El Solh, Ali A

    2009-02-01

    Nursing home-acquired pneumonia (NHAP) was first described in 1978. Since then there has been much written regarding NHAP and its management despite the lack of well-designed studies in this patient population. The most characteristic features of patients with NHAP are the atypical presentation, which may lead to delay in diagnosis and therapy. The microbial etiology of pneumonia encompasses a wide spectrum that spans microbes recovered from patients with community-acquired pneumonia to organisms considered specific only to nosocomial settings. Decision to transfer a nursing home patient to an acute care facility depends on a host of factors, which include the level of staffing available at the nursing home, patients' advance directives, and complexity of treatment. The presence of risk factors for multidrug-resistant pathogens dictates approach to therapy. Prevention remains the cornerstone of reducing the incidence of disease. Despite the advance in medical services, mortality from NHAP remains high.

  7. Spatial patterns of vegetation biomass and soil organic carbon acquired from airborne lidar and hyperspectral imagery at Reynolds Creek Critical Zone Observatory

    Science.gov (United States)

    Will, R. M.; Li, A.; Glenn, N. F.; Benner, S. G.; Spaete, L.; Ilangakoon, N. T.

    2015-12-01

    Soil organic carbon distribution and the factors influencing this distribution are important for understanding carbon stores, vegetation dynamics, and the overall carbon cycle. Linking soil organic carbon (SOC) with aboveground vegetation biomass may provide a method to better understand SOC distribution in semiarid ecosystems. The Reynolds Creek Critical Zone Observatory (RC CZO) in Idaho, USA, is approximately 240 square kilometers and is situated in the semiarid Great Basin of the sagebrush-steppe ecosystem. Full waveform airborne lidar data and Next-Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS-ng) collected in 2014 across the RC CZO are used to map vegetation biomass and SOC and then explore the relationships between them. Vegetation biomass is estimated by identifying vegetation species, and quantifying distribution and structure with lidar and integrating the field-measured biomass. Spectral data from AVIRIS-ng are used to differentiate non-photosynthetic vegetation (NPV) and soil, which are commonly confused in semiarid ecosystems. The information from lidar and AVIRIS-ng are then used to predict SOC by partial least squares regression (PLSR). An uncertainty analysis is provided, demonstrating the applicability of these approaches to improving our understanding of the distribution and patterns of SOC across the landscape.

  8. Input and output of dissolved organic and inorganic nitrogen in subtropical forests of South China under high air pollution

    Directory of Open Access Journals (Sweden)

    Y. T. Fang

    2008-03-01

    Full Text Available The nitrogen (N emissions to the atmosphere and N deposition to forest ecosystems are increasing rapidly in Southeast Asia, but little is known about the fates and effects of elevated N deposition in forest ecosystems in this warm and humid region. Here we report the concentrations and fluxes of dissolved inorganic (DIN and organic N (DON in precipitation, throughfall, surface runoff and soil solution for three subtropical forests in a region of South China under high air pollution over two years (2004 and 2005, to investigate how deposited N is processed, and to examine the importance of DON in the N budget. The precipitation DIN input was 32–34 kg N ha−1 yr−1. An additional input of 18 kg N ha−1 yr−1 as DON was measured in 2005, which to our knowledge is the highest DON flux ever measured in precipitation. A canopy uptake of DIN was indicated in two young conifer dominated forests (72–85% of DIN input reached the floor in throughfall, whereas no uptake occurred in an old-growth broadleaf forest. The DON fluxes in throughfall were similar to that in precipitation in all forests. In the younger forests, DIN was further retained in the soil, with 41–63% of precipitation DIN leached below the 20-cm soil depth. Additionally, about half of the DON input was retained in these forests. The N retention in two young aggrading forests (21–28 kg N ha−1 yr−1 was in accordance with the estimates of N accumulation in biomass and litter accretion. In the old-growth forest, no N retention occurred, but rather a net loss of 8–16 kg N ha−1 yr−1 from the soil was estimated. In total up to 60 kg N ha−1 yr−1 was leached from the old-growth forest, indicating that this forest was completely N saturated and could not retain additional anthropogenic N inputs. We found that the majority of DIN deposition as well as of DIN leaching

  9. Liu et al. suspect that Zhu et al. (2015) may have underestimated dissolved organic nitrogen (N) but overestimated total particulate N in wet deposition in China.

    Science.gov (United States)

    Liu, Xuejun; Xu, Wen; Pan, Yuepeng; Du, Enzai

    2015-07-01

    In a recent publication in the journal Science of the Total Environment, Zhu et al. (2015) reported the composition, spatial patterns, and factors influencing atmospheric wet nitrogen (N) deposition based on one year's data from 41-monitoring sites in China. We suspect their results may largely underestimate dissolved organic N (DON) but overestimate total particulate N (TPN) in wet deposition due to the uncertainty resulting from the sampling, storage and analysis methods in their study. Our suspicions are based mainly on our experience from earlier measurements and the literature. We therefore suggest that enhanced data quality control on atmospheric N deposition measurements should be taken into account in future studies.

  10. Influence, in organic cultivation of eggplant, of the doses of nitrogen and soil green cover on the incidence of Corythaica cyathicollis in different periods of the day

    Directory of Open Access Journals (Sweden)

    Raul de Lucena Duarte Ribeiro

    2007-12-01

    Full Text Available Solanum melongena L., eggplant, is a culture that suffers many problems through pests, being a host of diverse species of bacteria, fungi, mites and insects. The “chinch bug”, Corythaica cyathicollis (Costa, 1864 (Hemiptera, Tingidae is known to cause serious damage to the culture. This research was conducted in August of 2005, at the Federal Rural University of Rio de Janeiro (UFRRJ. The aim was to evaluate the effects of different doses of nitrogen (50, 100, 200 and 300kg/ha, different soil coverings (grass and Arachis pintoi, and periods of the day (morning, afternoon, evening on the population of the insect C. cyathycollis associated with the culture of S. melongena under organic system production. The delineation was in randomized blocks, with 12 treatments and 4 replications. Interaction was not verified among the studied factors (doses of nitrogen, soil covering and period of the day, but it was observed that the use of soil covering and low doses of nitrogen caused a reduction in the number of insect. The majority of insects were found during the period of the morning (39.2%.

  11. Metal-Organic Coordination Polymer to Prepare Density Controllable and High Nitrogen-Doped Content Carbon/Graphene for High Performance Supercapacitors.

    Science.gov (United States)

    Luo, Jinwei; Zhong, Wenbin; Zou, Yubo; Xiong, Changlun; Yang, Wantai

    2017-01-11

    Design and preparation of carbon-based electrode material with high nitrogen-doping ratio and appropriate density attract much interest for supercapacitors in practical application. Herein, three porous carbon/graphene (NCGCu, NCGFe, and NCGZn) with high doping ratio of nitrogen have been prepared via directly pyrolysis of graphene oxide (GO)/metal-organic coordination polymer (MOCP) composites, which were formed by reacting 4,4'-bipyridine (BPD) with CuCl2, FeCl3, and ZnCl2, respectively. As-prepared NCGCu, NCGFe and NCGZn showed high nitrogen doping ratio of 10.68, 12.99, and 11.21 at. %; and high density of 1.52, 0.84, and 1.15 g cm(-3), respectively. When as-prepared samples were used as supercapacitor electrodes, NCGCu, NCGFe and NCGZn exhibited high gravimetric specific capacitances of 369, 298.5, 309.5 F g(-1), corresponding to high volumetric specific capacitances of 560.9, 250.7, 355.9 F cm(-3) at a current density of 0.5 A g(-1), as well as good cycling stability, nearly 100% of the capacitance retained after 1000 cycles even at a large current density of 10 A g(-1). It is expected that the provided novel strategy can be used to develop electrode materials in high performance energy conversion/storage devices.

  12. Visible light induced photodegradation of organic pollutants on nitrogen and fluorine co-doped TiO2 photocatalyst

    Institute of Scientific and Technical Information of China (English)

    WANG Zheng-peng; XU Jun; CAI Wei-min; ZHOU Bao-xue; HE Zheng-guang; CAI Chun-guang; HONG Xiao-ting

    2005-01-01

    The nitrogen and fluorine co-doped TiO2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetrabutyl titanate with ammonium fluoride. Nitrogen and fluorine co-doping causes the absorption edge of TiO2 to shift to a lower energy region.The photocatalytic activity of co-doped TiO2 with anatase phases was found to be 2.4 times higher than that of the commercial TiO2photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co-doped TiO2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO2 powders from anatase to rutile.The substitutional fluorine and interstitial nitrogen atoms in co-doped TiO2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO2 to shift to a lower energy region.

  13. Water, organic matter, nitrogen and phosphorus contents in sediment of a large-scale mariculture area in the Zhelin Bay of eastern Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    DONG Qiaoxiang; LIN Junda; SHANG Xu; LI Jin; HUANG Changjiang

    2008-01-01

    The Zhelin Bay is one of the most important bays for large-scale maricuhure in Guangdong Province,China.Owing to the increas-ing human population and the expanding marieuhure in the last two decades,the ecological environment has greatly changed with frequent harmful algal blooms.A monthly survey of water content,organic matter ( TOM ),and various forms of nitrogen and phosphorous in sediment from July 2002 to July 2003 in the bay was conducted.The results showed that the water content was cor-related significantly with TOM and various forms of nitrogen and phosphorus and can be used as proxy for quick and rough estimate of these factors in the future surveys.TOM was also correlated significantly with various forms of nitrogen and phosphorus,indica-ting that it was one of the key factors affecting the concentrations and distributions of nitrogen and phosphorus in the investigated waters. Average total Kjeldhal nitrogen (TkN) Content was( 1113.1±382.5 )μg/g and average total phosphorus (TP) content was(567.2 ± 223.3)μg/g, and both were much higher than those of similar estuaries in China and elsewhere. Average nitrogen and phosphorus tended to be higher inside than outside the bay,higher at aquaculture than non-aquacuhure areas,and higher at fish-cage culture than oyster culture areas,suggesting that large-scale mariculture inside the bay played an important role in the eutrophication of the Zhelin Bay.Various forms of nitrogen and phosphorus concentrations were higher during the warm season (July--September),which was due to the increased decomposition and concentration of organic matter resulted from the fast growth and high mortality of the cultured species.Compared with July 2002,TkN and TP contents were much higher in July 2003,in consonance with the eut~'ophication of the Zhelin Bay.Because exchangeable phosphorus ( Ex-P),iron-bounded phos-phorus (Fe-P) and organic phosphorus (OP) combined accounted for 34.3% of the TP and authigenie phosphorus (Au-P) ac

  14. THE FATE AND RETENTION OF ORGANIC AND INORGANIC 15N-NITROGEN IN AN OLD-GROWTH FOREST SOIL IN WESTERN OREGON

    Science.gov (United States)

    Forests in the Pacific northwestern region of North America receive very little nitrogen through atmospheric deposition and thus can provide insights into how the nitrogen cycle functioned before heavy atmospheric deposition of inorganic nitrogen began in other regions. Our obje...

  15. Spatial and Temporal Variability of Dissolved Organic Carbon and Nitrogen Fluxes in the Hermine, a Forested Watershed of the Canadian Shield

    Science.gov (United States)

    Turgeon, J.; Courchesne, F.; Turmel, M.

    2004-05-01

    Recent studies have established the essential role of carbon (C) and nitrogen (N) in the biogeochemical cycles of elements in forested ecosystems (McDowell and Likens, 1988). Carbon and N are essential nutrients for biological processes and growth (Kalbitz et al. 2000; Buffam et al. 2001), and they play a key role in soil acidification, pedogenesis, trace metal and nutrient transport and mineral weathering (Likens and Bormann, 1995; Williams et al. 2001). However, there is a gap in knowledge regarding the spatial and temporal variability of C and N fluxes in forested ecosystems. Moreover, the factors controlling the fluxes of dissolved C and N at the event scale is poorly understood (Prechtel et al. 2000; McHale et al. 2000; Buffam et al.2001). In this context, the first objective of this study is to quantify the fluxes of dissolved organic carbon (DOC) and of dissolved N (NO3, NH4 and DON) between the biogeochemical compartments of a forested watershed (Hermine) at a range of temporal scales. The second objective is to identify the role of antecedent soil moisture conditions on the hydrochemistry of the stream, at the event scale. The results show that there is a significant difference (α = 0.05) in the concentrations of dissolved C and N between the five compartments (precipitation, throughfall, soil solution in the organic and mineral horizons and, stream). The fluxes of dissolved C and N increase as the water flows through the forest canopy to reach a maximum in the organic horizons. The decrease of dissolved C and N concentrations as the soil solution percolates through the mineral horizons is significant (α = 0.01) and is explained by the physico-chemical retention reactions (Guggenberger and Kaiser, 2003) and biological processes (Qualls and Haines, 1992). In all compartments, the speciation of total dissolved nitrogen is dominated by dissolved inorganic nitrogen (DIN). As water flows through the soil profile, the absolute dissolved organic nitrogen (DON

  16. Nitrogen isotopic composition of organic matter from a 168 year-old coral skeleton: Implications for coastal nutrient cycling in the Great Barrier Reef Lagoon

    Science.gov (United States)

    Erler, Dirk V.; Wang, Xingchen T.; Sigman, Daniel M.; Scheffers, Sander R.; Martínez-García, Alfredo; Haug, Gerald H.

    2016-01-01

    Ongoing human activities are known to affect nitrogen cycling on coral reefs, but the full history of anthropogenic impact is unclear due to a lack of continuous records. We have used the nitrogen isotopic composition of skeleton-bound organic matter (CS-δ15N) in a coastal Porites coral from Magnetic Island in the Great Barrier Reef as a proxy for N cycle changes over a 168 yr period (1820-1987 AD). The Magnetic Island inshore reef environment is considered to be relatively degraded by terrestrial runoff; given prior CS-δ15N studies from other regions, there was an expectation of both secular change and oscillations in CS-δ15N since European settlement of the mainland in the mid 1800s. Surprisingly, CS-δ15N varied by less than 1.5‰ despite significant land use change on the adjacent mainland over the 168-yr measurement period. After 1930, CS-δ15N may have responded to changes in local river runoff, but the effect was weak. We propose that natural buffering against riverine nitrogen load in this region between 1820 and 1987 is responsible for the observed stability in CS-δ15N. In addition to coral derived skeletal δ15N, we also report, for the first time, δ15N measurements of non-coral derived organic N occluded within the coral skeleton, which appear to record significant changes in the nature of terrestrial N inputs. In the context of previous CS-δ15N records, most of which yield CS-δ15N changes of at least 5‰, the Magnetic Island coral suggests that the inherent down-core variability of the CS-δ15N proxy is less than 2‰ for Porites.

  17. Importance of mineral cations and organics in gas-aerosol partitioning of reactive nitrogen compounds: case study based on MINOS results

    Directory of Open Access Journals (Sweden)

    S. Metzger

    2005-12-01

    Full Text Available The partitioning of reactive nitrogen compounds between the gas and the aerosol phase, as observed during the MINOS (Mediterranean INtensive Oxidant Study campaign in Crete, Greece, in July and August 2001, has been studied with three thermodynamic gas-aerosol equilibrium models (EQMs of different chemical complexity: ISORROPIA, which is limited to the ammonium sulfate-nitrate-sodium-chloride-water-system, SCAPE2, which also includes mineral elements (calcium, magnesium and potassium, and EQSAM2, which additionally accounts for organic acids. The different EQMs, as applied at the same level of complexity, generally produce comparable results within the range of measurement uncertainties (on average within ~10%, although they differ considerably in particular aspects. Model simulations of three distinct air pollution episodes during MINOS show that organic acids (lumped and soluble mineral cations need to be included in EQMs to accurately simulate the gas-aerosol partitioning of ammonia and nitric acid.

  18. The complete genome of Zunongwangia profunda SM-A87 reveals its adaptation to the deep-sea environment and ecological role in sedimentary organic nitrogen degradation

    Science.gov (United States)

    2010-01-01

    Background Zunongwangia profunda SM-A87, which was isolated from deep-sea sediment, is an aerobic, gram-negative bacterium that represents a new genus of Flavobacteriaceae. This is the first sequenced genome of a deep-sea bacterium from the phylum Bacteroidetes. Results The Z. profunda SM-A87 genome has a single 5 128 187-bp circular chromosome with no extrachromosomal elements and harbors 4 653 predicted protein-coding genes. SM-A87 produces a large amount of capsular polysaccharides and possesses two polysaccharide biosynthesis gene clusters. It has a total of 130 peptidases, 61 of which have signal peptides. In addition to extracellular peptidases, SM-A87 also has various extracellular enzymes for carbohydrate, lipid and DNA degradation. These extracellular enzymes suggest that the bacterium is able to hydrolyze organic materials in the sediment, especially carbohydrates and proteinaceous organic nitrogen. There are two clustered regularly interspaced short palindromic repeats in the genome, but their spacers do not match any sequences in the public sequence databases. SM-A87 is a moderate halophile. Our protein isoelectric point analysis indicates that extracellular proteins have lower predicted isoelectric points than intracellular proteins. SM-A87 accumulates organic osmolytes in the cell, so its extracelluar proteins are more halophilic than its intracellular proteins. Conclusion Here, we present the first complete genome of a deep-sea sedimentary bacterium from the phylum Bacteroidetes. The genome analysis shows that SM-A87 has some common features of deep-sea bacteria, as well as an important capacity to hydrolyze sedimentary organic nitrogen. PMID:20398413

  19. The complete genome of Zunongwangia profunda SM-A87 reveals its adaptation to the deep-sea environment and ecological role in sedimentary organic nitrogen degradation

    Directory of Open Access Journals (Sweden)

    Zhou Bai-Cheng

    2010-04-01

    Full Text Available Abstract Background Zunongwangia profunda SM-A87, which was isolated from deep-sea sediment, is an aerobic, gram-negative bacterium that represents a new genus of Flavobacteriaceae. This is the first sequenced genome of a deep-sea bacterium from the phylum Bacteroidetes. Results The Z. profunda SM-A87 genome has a single 5 128 187-bp circular chromosome with no extrachromosomal elements and harbors 4 653 predicted protein-coding genes. SM-A87 produces a large amount of capsular polysaccharides and possesses two polysaccharide biosynthesis gene clusters. It has a total of 130 peptidases, 61 of which have signal peptides. In addition to extracellular peptidases, SM-A87 also has various extracellular enzymes for carbohydrate, lipid and DNA degradation. These extracellular enzymes suggest that the bacterium is able to hydrolyze organic materials in the sediment, especially carbohydrates and proteinaceous organic nitrogen. There are two clustered regularly interspaced short palindromic repeats in the genome, but their spacers do not match any sequences in the public sequence databases. SM-A87 is a moderate halophile. Our protein isoelectric point analysis indicates that extracellular proteins have lower predicted isoelectric points than intracellular proteins. SM-A87 accumulates organic osmolytes in the cell, so its extracelluar proteins are more halophilic than its intracellular proteins. Conclusion Here, we present the first complete genome of a deep-sea sedimentary bacterium from the phylum Bacteroidetes. The genome analysis shows that SM-A87 has some common features of deep-sea bacteria, as well as an important capacity to hydrolyze sedimentary organic nitrogen.

  20. Distribution of trace elements in organs of six species of cetaceans from the Ligurian Sea (Mediterranean), and the relationship with stable carbon and nitrogen ratios

    Energy Technology Data Exchange (ETDEWEB)

    Capelli, R. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Das, K. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Pellegrini, R. De; Drava, G. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Lepoint, G. [MARE center, Laboratory for Oceanology, University of Liege, B6 Sart-Tilman, B-4000 Liege (Belgium); Miglio, C. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy); Minganti, V. [Dipartimento di Chimica e Tecnologie Farmaceutiche ed Alimentari - Universita degli Studi di Genova - Via Brigata Salerno, 13 I-16147 Genova (Italy)], E-mail: minganti@dictfa.unige.it; Poggi, R. [Museo Civico di Storia Naturale ' Giacomo Doria' - Via Brigata Liguria, 9 I-16121 Genova (Italy)

    2008-02-15

    Mercury (total and organic), cadmium, lead, copper, iron, manganese, selenium and zinc concentrations were measured in different organs of 6 different cetacean species stranded in an area of extraordinary ecological interest (Cetaceans' Sanctuary of the Mediterranean Sea) along the coast of the Ligurian Sea (North-West Mediterranean). Stable-isotopes ratios of carbon ({sup 13}C/{sup 12}C) and nitrogen ({sup 15}N/{sup 14}N) were also measured in the muscle. A significant relationship exists between {sup 15}N/{sup 14}N, mercury concentration and the trophic level. The distribution of essential and non-essential trace elements was studied on several organs, and a significant relationship between selenium and mercury, with a molar ratio close to 1, was found in the cetaceans' kidney, liver and spleen, regardless of their species. High selenium concentrations are generally associated with a low organic to total mercury ratio. While narrow ranges of concentrations were observed for essential elements in most organs, mercury and selenium concentrations are characterised by a wide range of variation. Bio-accumulation and bio-amplification processes in cetaceans can be better understood by comparing trace element concentrations with the stable-isotopes data.

  1. Predicting the export and concentrations of organic carbon, nitrogen and phosphorus in boreal lakes by catchment characteristics and land use: A practical approach.

    Science.gov (United States)

    Palviainen, Marjo; Laurén, Ari; Launiainen, Samuli; Piirainen, Sirpa

    2016-12-01

    The majority of C, N and P in boreal lakes are in organic form. Organically bound nutrients are released through biodegradation or photodegradation which affects the water quality, eutrophication and greenhouse gas emissions of lakes. We tested whether open land-use data combined with land-use-specific export coefficients can be used to predict total organic carbon (TOC), dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) loading and lake water concentrations. Using data from 12 lake catchments in eastern Finland, we found that land use and management of the catchment explained a substantial proportion of the variations in TOC (r (2) = 0.78), DON (r (2) = 0.55) and DOP (r (2) = 0.80) concentrations between lakes. The computation does not account for in-lake processes, which are reflected as mismatch between the predicted and observed concentrations. However, this simple practical approach is useful in ranking lakes according to their water quality. The results indicated that natural sources dominate TOC, DON and DOP exports; the background leachings accounted for 57-99 %, 48-96 % and 55-99 % of TOC, DON and DOP export, respectively. The proposed method has promise as a practical decision support tool for assessing the impacts of land use on water quality. The results showed that possibilities to control TOC, DON and DOP loading to surface waters are limited to catchments where the peatland proportion is low and anthropogenic sources significant.

  2. Activated carbon-based magnetic TiO2 photocatalyst codoped with iodine and nitrogen for organic pollution degradation

    Science.gov (United States)

    Wang, Xuejiang; Song, Jingke; Huang, Jiayu; Zhang, Jing; Wang, Xin; Ma, RongRong; Wang, Jiayi; Zhao, Jianfu

    2016-12-01

    Magnetic photocatalyst - iodine and nitrogen codoped TiO2 based on chitosan decorated magnetic activated carbon (I-N-T/CMAC) was prepared via simple coprecipitation and sol-gel method. The characteristics of photocatalysts were investigated by X-ray diffraction (XRD), N2 adsorption-desorption isotherm, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). It turned out that the prepared material had large surface area, enhanced absorption of visible light, and magnetically separable properties when mole ratio of I/Ti was 0.1. Iodine-nitrogen codoped magnetic photocatalyst was used for the removal of salicylic acid (SA), and the rate of adsorption reaction for SA by I0.1-N-T/CMAC followed the pseudo second-order kinetic. Under visible light irradiation, 89.71% SA with initial concentration = 30 mg/L could be removed by I0.1-N-T/CMAC, and photodegradation rate of SA on I0.1-N-T/CMAC composites was 0.0084 min-1 which is about 4 times higher than that of magnetic photocatalyst with nitrogen doped only. The effects of SA initial concentration, pH, coexisting anions and humic acid to the degradation of SA with the prepared material were also investigated. Main oxidative species in the photodegradation process are rad OH and h+.

  3. Carbon and nitrogen isotopic composition of suspended particulate organic matter in Zuari Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Bardhan, P.; Karapurkar, S.G.; Shenoy, D.M.; Kurian, S.; Sarkar, A.; Maya, M.V.; Naik, H.; Varik, S.; Naqvi, S.W.A.

    -situ and detrital (plankton and terrestrial) organic matter are the two major pools of organic matter in the Zuari estuary. Acknowledgements This research was carried out as a part of SIBER-INDIA project funded by the Ministry of Earth Sciences (MoES). P... induced changes than they are today. It is essential to understand the origin and transformation pathways of organic matter in various estuarine and coastal systems in order to assess the current state of these ecosystems globally and predict...

  4. Acquired cutis laxa

    Directory of Open Access Journals (Sweden)

    Musaliar S

    2003-03-01

    Full Text Available A 13-yeat-old male patient born of non consanguineous marriage with history of recurrent urticaria and angioedema for the past 2 years presented with wrinkling and laxity of the skin over the face, axilla and abdomen. Histopathology was consistent with cutis laxa. We are reporting a rare case of acquired cutis laxa due to recurrent urticaria.

  5. Acquired cutis laxa

    Directory of Open Access Journals (Sweden)

    Musaliar S

    2003-01-01

    Full Text Available A 13-yeat-old male patient born of non consanguineous marriage with history of recurrent urticaria and angioedema for the past 2 years presented with wrinkling and laxity of the skin over the face, axilla and abdomen. Histopathology was consistent with cutis laxa. We are reporting a rare case of acquired cutis laxa due to recurrent urticaria.

  6. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

    OpenAIRE

    Xianbiao Lin; Lijun Hou; Min Liu; Xiaofei Li; Guoyu Yin; Yanling Zheng; Fengyu Deng

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization i...

  7. Cover plants and mineral nitrogen: effects on organic matter fractions in an oxisol under no-tillage in the cerrado

    Directory of Open Access Journals (Sweden)

    Isis Lima dos Santos

    2014-12-01

    Full Text Available Cover plants are essential for the sustainability of no-tillage systems in tropical regions. However, information on the effects of these plants and N fertilization on soil organic matter fractions is still scarce. This study evaluated the effect of cover crops with different chemical composition and of N topdressing on the labile and humified organic matter fractions of an Oxisol of the Cerrado (savanna-like vegetation. The study in a randomized complete block design was arranged in split-plots with three replications. Four cover species were tested in the plots and the presence or absence of N topdressing in the subplot. The following cover species were planted in succession to corn for eight years: Urochloa ruziziensis; Canavalia brasiliensis M. ex Benth; Cajanus cajan (L. Millsp; and Sorghum bicolor (L. Moench. In general, the cultivation of U. ruziziensis increased soil C levels, particularly of C in the humic acid and particulate organic C fractions, which are quality indicators of soil organic matter. The C in humic substances and mineral organic C accounted for the highest proportions of total organic C, demonstrating the strong interaction between organic matter, Fe and Al oxides and kaolinite, which are predominant in these weathered soils of the Cerrado.

  8. A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus

    Science.gov (United States)

    Vet, Robert; Artz, Richard S.; Carou, Silvina

    2014-08-01

    Investigating and assessing the chemical composition of precipitation and atmospheric deposition is essential to understanding how atmospheric pollutants contribute to contemporary environmental concerns including ecosystem acidification and eutrophication, loss of biodiversity, air pollution and global climate change. Evidence of the link between atmospheric deposition and these environmental issues is well established. The state of scientific understanding of this link is that present levels of atmospheric deposition of sulfur and nitrogen adversely affect terrestrial and aquatic ecosystems, putting forest sustainability and aquatic biodiversity at risk. Nitrogen and phosphorus loadings are linked to impacts on the diversity of terrestrial and aquatic vegetation through biological cycling, and atmospheric deposition plays a major role in the emission-transport-conversion-loss cycle of chemicals in the atmosphere as well as the formation of particulate matter and ozone in the troposphere. Evidence also shows that atmospheric constituents are changing the earth's climate through direct and indirect atmospheric processes. This Special Issue, comprising a single article titled "A global assessment of precipitation chemistry and deposition of sulfur, nitrogen, sea salt, base cations, organic acids, acidity and pH, and phosphorus", presents a recent comprehensive review of precipitation chemistry and atmospheric deposition at global and regional scales. The information in the Special Issue, including all supporting data sets and maps, is anticipated to be of great value not only to the atmospheric deposition community but also to other science communities including those that study ecosystem impacts, human health effects, nutrient processing, climate change, global and hemispheric modeling and biogeochemical cycling. Understanding and quantifying pollutant loss from the atmosphere is, and will remain, an important component of each of these scientific fields as they

  9. Synthesis of adenine, guanine, cytosine, and other nitrogen organic compounds by a Fischer-Tropsch-like process.

    Science.gov (United States)

    Yang, C. C.; Oro, J.

    1971-01-01

    Study of the formation of purines, pyrimidines, and other bases from CO, H2, and NH3 under conditions similar to those used in the Fischer-Tropsch process. It is found that industrial nickel/iron alloy catalyzes the synthesis of adenine, guanine, cytosine, and other nitrogenous compounds from mixtures of CO, H2, and NH3 at temperatures of about 600 C. Sufficient sample was accumulated to isolate as solid products adenine, guanine, and cytosine, which were identified by infrared spectrophotometry. In the absence of nickel/iron catalyst, at 650 C, or in the presence of this catalyst, at 450 C, no purines or pyrimidines were synthesized. These results confirm and extend some of the work reported by Kayatsu et al. (1968).

  10. Evaluation of nitrogen and organic matter balance in the feedlot as affected by level and source of dietary fiber.

    Science.gov (United States)

    Bierman, S; Erickson, G E; Klopfenstein, T J; Stock, R A; Shain, D H

    1999-07-01

    A trial was conducted to determine the effect of level and source of dietary fiber on N and OM excretion by cattle on finishing diets. One hundred twenty steers were stratified by weight and allotted to one of the following treatments: 7.5% roughage (7.5% R), wet corn gluten feed (WCGF; 41.5% of dietary DM), and all-concentrate (All Con) diet. Cattle were fed for 87 d during the summer with 23.7 m2 of pen area per animal. Steers fed the WCGF diet had heavier final weights, greater DMI, and higher ADG (P < .01) than the 7.5% R and All Con treatments. Steers fed All Con had lower (P < .01) DMI than the other two treatments. Nitrogen and OM mass balances in the feedlot were quantified. Main components were nutrient input, retention, and excretion. Nitrogen and OM intake of steers fed WCGF were greater (P < .05) than those of steers fed the other treatments. The WCGF treatment had a greater percentage of fecal N output (P < .05). The All Con treatment had a greater (P < .01) percentage of urinary N than WCGF and 7.5% R diets. Steers fed the WCGF treatment excreted more (P < .01) OM compared with the other treatments, which led to more N and OM being removed in manure at cleaning. The All Con treatment had more (P < .01) N and OM in runoff than the other treatments. Nutrition can change site of fermentation, which affects the composition of excreted material; however, total amount of N excreted may be more important than route of excretion in decreasing N losses to the environment and maximizing recovery in manure.

  11. Nitrogen in Chinese coals

    Science.gov (United States)

    Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

    2011-01-01

    Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

  12. Microbial conversions of nitrogenous heterocycles

    OpenAIRE

    Parshikov, Igor A

    2015-01-01

    The monography describes examples of the application of microbial technologies for obtaining of derivatives from a series of nitrogen heterocycles (saturated nitrogen heterocycles, azaarenes and quinolones). It is proposed alternative ways for synthesize substances that are difficult to obtain by the methods of organic chemistry. Microbial technologies of synthesis of organic compounds may find out a practical application in the production of various drugs.

  13. Acquired methemoglobinemia in infants

    Directory of Open Access Journals (Sweden)

    Mehmet Mutlu

    2011-06-01

    Full Text Available Objective: This study aimed to determine the etiologic factors of acquired methemoglobinemia in infants younger than three months in our region. Material and Methods: This study was carried out retrospectively in infants with methemoglobinemia admitted to Karadeniz Technical University, Pediatric Clinic, during the period 2000-2009. Infants with methemoglobinemia were identified according to the medical records or ICD-10 code. Results: Nine infants with acquired methemoglobinemia (8 male, 1 female were included in the study. Seven cases were associated with the use of prilocaine for circumcision, one case with the use of prilocaine-lidocaine for local pain therapy, and one case with neonatal sepsis caused by Staphylococcus aureus.Conclusion: Prilocaine should not be used in infants less than three months of age because of the risk of methemoglobinemia. Ascorbic acid is an effective therapy if methylene blue is not obtained. It should not be forgotten that sepsis caused by S. aureus may cause methemoglobinemia in infants.

  14. Acquired hypertrichosis lanuginosa

    Directory of Open Access Journals (Sweden)

    Kumar Pramod

    1993-01-01

    Full Text Available Acquired hypertirichosis lanuginose developed rapidly in a patient with no detectable malignancy. Soft, fine, downy hair growth was noticed on the face, ears, limbs and trunk. Bilaterally symmetrical vitiliginous macules were present on the ear and preauricular region. This case is reported because of its rarity, absence of any detectable malignancy and development of vitiligo, which to our knowledge has not been reported earlier.

  15. Synthesis of Two-Dimensional CoS1.097/Nitrogen-Doped Carbon Nanocomposites Using Metal-Organic Framework Nanosheets as Precursors for Supercapacitor Application.

    Science.gov (United States)

    Cao, Feifei; Zhao, Meiting; Yu, Yifu; Chen, Bo; Huang, Ying; Yang, Jian; Cao, Xiehong; Lu, Qipeng; Zhang, Xiao; Zhang, Zhicheng; Tan, Chaoliang; Zhang, Hua

    2016-06-01

    Two-dimensional (2D) metal-organic framework (MOF) nanosheets are attracting increasing research interest. Here, for the first time, we report the facile synthesis of 2D porphyrin paddlewheel framework-3 (PPF-3) MOF nanosheets with thickness of ca. 12-43 nm. Through the simultaneous sulfidation and carbonization of PPF-3 MOF nanosheets, we have prepared the 2D nanocomposite of CoS1.097 nanoparticles (NPs) and nitrogen-doped carbon, referred to as CoSNC, in which the CoS1.097 NPs with size of ca. 10 nm are embedded in the nitrogen-doped carbon matrix. As a proof-of-concept application, the obtained 2D CoSNC nanocomposite is used as an electrode material for a supercapacitor, which exhibits a specific capacitance of 360.1 F g(-1) at a current density of 1.5 A g(-1). Moreover, the composite electrode also shows high rate capability. Its specific capacitance delivered at a current density of 30.0 A g(-1) retains 56.8% of the value at 1.5 A g(-1).

  16. The use of the carbon/nitrogen ratio and specific organic loading rate as tools for improving biohydrogen production in fixed-bed reactors

    Directory of Open Access Journals (Sweden)

    Mélida del Pilar Anzola-Rojas

    2015-03-01

    Full Text Available This study assessed the effect of the carbon/nitrogen (C/N ratio on the hydrogen production from sucrose-based synthetic wastewater in upflow fixed-bed anaerobic reactors. C/N ratios of 40, 90, 140, and 190 (g C/g N were studied using sucrose and urea as the carbon and nitrogen sources, respectively. An optimum hydrogen yield of 3.5 mol H2 mol−1 sucrose was obtained for a C/N ratio of 137 by means of mathematical adjustment. For all C/N ratios, the sucrose removal efficiency reached values greater than 80% and was stable after the transient stage. However, biogas production was not stable at all C/N ratios as a consequence of the continuous decreasing of the specific organic loading rate (SOLR when the biomass accumulated in the fixed-bed, causing the proliferation of H2-consuming microorganisms. It was found that the application of a constant SOLR of 6.0 g sucrose g−1 VSS d−1 stabilized the system.

  17. 青岛大气气溶胶中水溶性有机氮对总氮的贡献%Contribution of Water Soluble Organic Nitrogen to Total Nitrogen in Atmospheric Aerosols in Qingdao

    Institute of Scientific and Technical Information of China (English)

    石金辉; 韩静; 范得国; 祁建华; 高会旺

    2011-01-01

    Organic nitrogen (ON) is a quantitatively important component of reactive nitrogen in atmospheric aerosols. Deposition of ON in seawater from atmosphere could enhance primary productivity, as well as with the changes in the phytoplankton community composition. 64 total suspended particles (TSP) samples collected at Qingdao from January to December in 2008 were applied to analyze the concentrations of water soluble organic nitrogen in aerosols. Concentrations of ON in Qingdao aerosols ranged from 30 to 2 073 nmol.m -3 ( 100-12 157 p mol-g-1 ) , with the highest values occurring in December, followed in March and April and the lowest values in June to September. ON mean concentration in TSP in 2008 was 430 nmol·m -3 (2 323 μmol.g-1 ). The contribution of ON to total nitrogen (TN) was (37.5 ± 21.6)%, with the maximum presenting in December and the minimum in September. The distribution of organic nitrogen in aerosols was significantly affected by the weather conditions. During haze and fog episodes, the concentrations of ON in the aerosols were 789 nmol·m-3 and 412 nmol.m-3, respectively, 4 times and twice higher than that during clear episodes. However, the particle mass concentrations in haze and fog days were comparable with that in clear days. During dust episodes, the concentration of particles was 5 times higher than that during clear episodes while ON concentration slightly enhanced 0.4 times. The ON concentration in aerosols after raining was 57 nmol. m -3 ,decreased 80% than that before raining due to the efficient wet scavenging.%有机氮是大气气溶胶中重要的氮组分,其沉降入海后不仅能够促进海洋初级生产力的增长,还可能影响海洋生态系统的群落结构.利用2008年1~12月在青岛采集的64个总悬浮颗粒物样品,分析了其中水溶性有机氮的浓度.气溶胶中有机氮的浓度为30~2 073 nmol·m-3(100~12 157 μmol·g-1),以12月浓度最高,3、4月次之,6~9

  18. The generation of 4-hydroxynonenal, an electrophilic lipid peroxidation end product, in rabbit cornea organ cultures treated with UVB light and nitrogen mustard

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ruijin; Po, Iris; Mishin, Vladimir; Black, Adrienne T. [Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Heck, Diane E. [Environmental Science, New York Medical College, Valhalla, NY (United States); Laskin, Debra L. [Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Sinko, Patrick J. [Pharmaceutics, Rutgers University, Piscataway, NJ (United States); Gerecke, Donald R.; Gordon, Marion K. [Pharmacology and Toxicology, Rutgers University, Piscataway, NJ (United States); Laskin, Jeffrey D., E-mail: jlaskin@eohsi.rutgers.edu [Environmental and Occupational Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ (United States)

    2013-10-15

    The cornea is highly sensitive to oxidative stress, a process that can lead to lipid peroxidation. Ultraviolet light B (UVB) and nitrogen mustard (mechlorethamine) are corneal toxicants known to induce oxidative stress. Using a rabbit air-lifted corneal organ culture model, the oxidative stress responses to these toxicants in the corneal epithelium was characterized. Treatment of the cornea with UVB (0.5 J/cm{sup 2}) or nitrogen mustard (100 nmol) resulted in the generation of 4-hydroxynonenal (4-HNE), a reactive lipid peroxidation end product. This was associated with increased expression of the antioxidant, heme oxygenase-1 (HO-1). In human corneal epithelial cells in culture, addition of 4-HNE or 9-nitrooleic acid, a reactive nitrolipid formed during nitrosative stress, caused a time-dependent induction of HO-1 mRNA and protein; maximal responses were evident after 10 h with 30 μM 4-HNE or 6 h with 10 μM 9-nitrooleic acid. 4-HNE and 9-nitrooleic acid were also found to activate Erk1/2, JNK and p38 MAP kinases, as well as phosphoinositide-3-kinase (PI3)/Akt. Inhibition of p38 blocked 4-HNE- and 9-nitrooleic acid-induced HO-1 expression. Inhibition of Erk1/2, and to a lesser extent, JNK and PI3K/Akt, suppressed only 4-HNE-induced HO-1, while inhibition of JNK and PI3K/Akt, but not Erk1/2, partly reduced 9-nitrooleic acid-induced HO-1. These data indicate that the actions of 4-HNE and 9-nitrooleic acid on corneal epithelial cells are distinct. The sensitivity of corneal epithelial cells to oxidative stress may be an important mechanism mediating tissue injury induced by UVB or nitrogen mustard. - Highlights: • UVB or nitrogen mustard causes rabbit corneal epithelial injury. • 4-Hydroxynonenal (4-HNE) was formed and heme oxygenase-1 (HO-1) was increased. • 4-HNE induced HO-1 mRNA and protein expression in human corneal epithelial cells. • The induction of HO-1 by 4-HNE was through MAP kinase activation.

  19. Effects of packing rates of cubic-shaped polyurethane foam carriers on the microbial community and the removal of organics and nitrogen in moving bed biofilm reactors.

    Science.gov (United States)

    Feng, Quan; Wang, Yuxiao; Wang, Tianmin; Zheng, Hao; Chu, Libing; Zhang, Chong; Chen, Hongzhang; Kong, Xiuqin; Xing, Xin-Hui

    2012-08-01

    The effects of packing rates (20%, 30%, and 40%) of polyurethane foam (PUF) to the removal of organics and nitrogen were investigated by continuously feeding artificial sewage in three aerobic moving bed biofilm reactors. The results indicated that the packing rate of the PUF carriers had little influence on the COD removal efficiency (81% on average). However, ammonium removal was affected by the packing rates, which was presumably due to the different relative abundances of nitrifying bacteria. A high ammonium removal efficiency of 96.3% at a hydraulic retention time of 5h was achieved in 40% packing rate reactor, compared with 37.4% in 20% packing rate. Microprofiles of dissolved oxygen and nitrate revealed that dense biofilm limits the DO transfer distance and nitrate diffusion. Pyrosequencing analysis of the biofilm showed that Proteobacteria, Bacteroidetes and Verrucomicrobia were the three most abundant phyla, but the proportions of the microbial community varied with the packing rate of the PUF carriers.

  20. Ultrafast Li-storage of MoS2 nanosheets grown on metal-organic framework-derived microporous nitrogen-doped carbon dodecahedrons

    Science.gov (United States)

    Shao, Jie; Gao, Tian; Qu, Qunting; Shi, Qiang; Zuo, Zhichen; Zheng, Honghe

    2016-08-01

    The nanocomposites of MoS2 nanosheets and microporous nitrogen-doped carbon dodecahedron (MNCD) are prepared through the pyrolysis of metal-organic framework (MOF) and subsequent growth of MoS2. The porous and active surface of MNCDs enables uniform growth of ultrathin MoS2 nanosheets. When the MNCD@MoS2 composite is used as the anode material of Li-ion batteries, a reversible capacity of 915 mAh g-1 can be obtained even at the extremely high current density of 10 A g-1. The ultrafast charge/discharge ability of MNCD@MoS2 can be attributed to its unique core-shell structure with the inner MNCDs serving as the reservoir of Li-ions and transport media of electrons.

  1. Interactions of Water Management and Nitrogen Fertilizer on Nitrogen Absorption and Utilization in Rice

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-hua; CAO Wei-xing; DING Yan-feng; TIAN Yong-chao; JIANG Dong

    2003-01-01

    The interactions of water management and nitrogen fertilizer on nitrogen absorption and utili-zation were studied in rice with Wuxiangjing9 (japonica). The results showed that the nitrogen uptake and re-maining in straw increased and the percentage of nitrogen translocation (PNT) from vegetative organs, nitro-gen dry matter production efficiency (NDMPE) and nitrogen grain production efficiency (NGPE) decreasedwith nitrogen increasing. The nitrogen uptake and NGPE decreased when severe water stressed. However, ricenot only decreased the nitrogen uptake but also increased the PNT from vegetative organs, NDMPE and NGPEwhen mild water stressed. There were obvious interactions between nitrogen fertilizer and water management,such as with water stress increasing the effect of nitrogen on increasing nitrogen uptake was reduced and thaton decreasing NDMPE was intensified.

  2. Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem

    Science.gov (United States)

    Stackpoole, S.M.; Kosola, K.R.; Workmaster, B.A.A.; Guldan, N.M.; Browne, B.A.; Jackson, R. D.

    2011-01-01

    Even though nitrogen (N) is a key nutrient for successful cranberry production, N cycling in cranberry agroecosystems is not completely understood. Prior research has focused mainly on timing and uptake of ammonium fertilizer, but the objective of our study was to evaluate the potential for additional N contributions from hydrologic inputs (flooding, irrigation, groundwater, and precipitation) and organic matter (OM). Plant biomass, soil, surface and groundwater samples were collected from five cranberry beds (cranberry production fields) on four different farms, representing both upland and lowland systems. Estimated average annual plant uptake (63.3 ?? 22.5 kg N ha-1 year-1) exceeded total average annual fertilizer inputs (39.5 ?? 11.6 kg N ha-1 year-1). Irrigation, precipitation, and floodwater N summed to an average 23 ?? 0.7 kg N ha-1 year-1, which was about 60% of fertilizer N. Leaf and stem litterfall added 5.2 ?? 1.2 and 24.1 ?? 3.0 kg N ha-1 year-1 respectively. The estimated net N mineralization rate from the buried bag technique was 5 ?? 0.2 kg N ha-1 year-1, which was nearly 15% of fertilizer N. Dissolved organic nitrogen represented a significant portion of the total N pool in both surface water and soil samples. Mixed-ion exchange resin core incubations indicated that 80% of total inorganic N from fertilizer, irrigation, precipitation, and mineralization was nitrate, and approximately 70% of recovered inorganic N from groundwater was nitrate. There was a weak but significant negative relationship between extractable soil ammonium concentrations and ericoid mycorrhizal colonization (ERM) rates (r = -0.22, P fertilizer N in order to maximize the benefits of ERM fungi in actively mediating N cycling in cranberry agroecosystems. ?? 2011 Springer Science+Business Media B.V.

  3. Nocturnal isoprene oxidation over the Northeast United States in summer and its impact on reactive nitrogen partitioning and secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    S. S. Brown

    2009-01-01

    Full Text Available Isoprene is the largest single VOC emission to the atmosphere. Although it is primarily oxidized photochemically during daylight hours, late-day emissions that remain in the atmosphere at sunset undergo oxidation by NO3 in regionally polluted areas with large NOx levels. A recent aircraft study examined isoprene and its nocturnal oxidants in a series of night flights across the Northeast US, a region with large emissions of both isoprene and NOx. Substantial amounts of isoprene that were observed after dark were strongly anticorrelated with measured NO3 and were the most important factor determining the lifetime of this radical. The products of photochemical oxidation of isoprene, methyl vinyl ketone and methacrolein, were more uniformly distributed, and served as tracers for the presence of isoprene at sunset, prior to its oxidation by NO3. Comparison of a determination of the mass of isoprene oxidized in darkness by NO3 to a calculation of integrated isoprene emissions showed that large amounts (>20% of emitted isoprene may undergo nocturnal oxidation in this region. Organic nitrates produced from the NO3+isoprene reaction, though not directly measured, were estimated to account for 2–9% of total reactive nitrogen and 7–31% of other long-lived organic nitrates such as PAN. The mass of isoprene oxidized by NO3 was comparable to and correlated with the organic aerosol loading for flights with relatively low organic aerosol background. The contribution of nocturnal isoprene oxidation to secondary organic aerosol was determined in the range 1–17%, and isoprene SOA mass derived from NO3 was calculated to exceed that due to OH by approximately 50%.

  4. The effects of rising atmospheric carbon dioxide on shoot-root nitrogen and water signaling

    Directory of Open Access Journals (Sweden)

    Hsien Ming eEaslon

    2013-08-01

    Full Text Available Terrestrial higher plants are composed of roots and shoots, distinct organs that conduct complementary functions in dissimilar environments. For example, roots are responsible for acquiring water and nutrients such as inorganic nitrogen from the soil, yet shoots consume the majority of these resources. The success of such a relationship depends on excellent root-shoot communications. Increased net photosynthesis and decreased shoot nitrogen and water use at elevated CO2 fundamentally alter these source-sink relations. Lower than predicted productivity gains at elevated CO2 under nitrogen or water stress may indicate shoot-root signaling lacks plasticity to respond to rising atmospheric CO2 concentrations. The following presents recent research results on shoot-root nitrogen and water signaling, emphasizing the influence that rising atmospheric carbon dioxide levels are having on these source-sink interactions.

  5. Approaches to Determining the Oxidation State of Nitrogen and Carbon Atoms in Organic Compounds for High School Students

    Science.gov (United States)

    Jurowski, Kamil; Krzeczkowska, Malgorzata Krystyna; Jurowska, Anna

    2015-01-01

    The concept of oxidation state (or oxidation number) and related issues have always been difficult for students. In addition, there are misunderstandings and obscurities, which can cause improper balancing of the chemical equations (mostly in organic reactions). In particular, these problems are related to determination of the oxidation state of…

  6. Economy of Fertilizer Nitrogen through Organic Sources in Rain-Fed Rice-Legume Cropping Systems in West Bengal, India

    Directory of Open Access Journals (Sweden)

    A.M. Puste

    2001-01-01

    Full Text Available Field experiments were conducted at a farmers’ plot adjacent to the Regional Research Station, red and laterite zone, Sub-center Sekhampur (Birbhum district of West Bengal, India, situated 23° 24' N latitude, 87° 24' E longitude, to study the effect of different bio- and organic sources of nutrients instead of total fertilizer N in terms of crop productivity in the sequence and building up of soil fertility. During the wet seasons of 1997 and 1998, 12 combinations of bio- and organic sources (crop residues, well decomposed cow dung, dhanicha as green manure were substituted for 25–50% of N fertilizer applied on transplanted rice (Cv. IR 36. Subsequently, during the winters of 1997–1998 and 1998–1999, leguminous pulse crops like lentil (Lens culinaris [L.] Medic., gram (Cicer arietinum L. and lathyrus (Lathyrus sativus L. were grown with and without inoculation of Rhizobium. Results revealed that the application of inorganic N in combination with organic sources exhibited a significant increase in rice yield (3.60–3.84 t ha-1 compared to the yield from sole application of N (3.19–3.26 t ha-1. The study showed that about 25% of total applied N was saved without significant yield reduction with simultaneous improvement of soil physical properties (pH, organic matter, available N, P, K, and CEC. Seed yield of pulses (lentil, gram, and lathyrus were more pronounced in the treatment inoculated with Rhizobium, with a saving of 42.6–48.4 kg N ha-1. Therefore, the results suggest that the combined application of inorganic and organic N sources in a 75:25 ratio is a superior N-management practice with regards to crop yields as well as improvement of soil fertility.

  7. Acquired von Willebrand Syndrome

    Institute of Scientific and Technical Information of China (English)

    郭涛

    2005-01-01

    @@ Acquired von Willebrand syndrome (AvWS) is kind of bleeding disorder with laboratory findings similar to those in congenital yon Willebrand disease (vWD).AvWS doesn's have any personal or family history of bleeding, but is associated with certain diseases or abnormal conditions or drugs. Although AvWS is being stated as a rare disease, it has gained more and more attention during the past years. Not because of the severity of the disease, but it is more common than we thought and most patients don' t have a proper diagnosis.

  8. Acquired hyperostosis syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Dihlmann, W.; Hering, L.; Bargon, G.W.

    1988-10-01

    Sterno-costo-clavicular hyperostosis (SCCH) is the most common manifestation of a syndrome, consisting of increased bone metabolism, mostly new bone formation and heterotopic ossification of fibrous tissue, which we have characterised as the acquired hyperostosis syndrome. In part I we discuss the terminology, radiological appearances, scintigraphy, clinical and laboratory findings, bacteriology, histology, nosology, complications, treatment and differential diagnosis of SCCH. Chronic recurrent multifocal osteomyelitis (CRMO) is regarded as a phaenotype of SCCH, depending on the age. CRMO occurs in children, adolescents and young adults, SCCH predominantly in middleaged and elderly adults.

  9. Modeling organic matter and nitrogen removal from domestic wastewater in a pilot-scale vertical subsurface flow constructed wetland.

    Science.gov (United States)

    Bustillo-Lecompte, Ciro Fernando; Mehrvar, Mehrab; Quiñones-Bolaños, Edgar; Castro-Faccetti, Claudia Fernanda

    2016-01-01

    Constructed wetlands have become an attractive alternative for wastewater treatment. However, there is not a globally accepted mathematical model to predict their performance. In this study, the VS2DTI software was used to predict the effluent biochemical oxygen demand (BOD) and total nitrogen (TN) in a pilot-scale vertical flow constructed wetland (VFCW) treating domestic wastewater. After a 5-week adaptation period, the pilot system was monitored for another 6 weeks. Experiments were conducted at hydraulic retention times (HRTs) in the range of 2-4 days with Typha latifolia as the vegetation. The raw wastewater concentrations ranged between 144-430 and 122-283 mg L(-1) for BOD5 and TN, respectively. A first-order kinetic model coupled with the advection/dispersion and Richards' equations was proposed to predict the removal rates of BOD5 and TN from domestic wastewater. Two main physical processes were modeled in this study, porous material water flow and solute transport through the different layers of the VFCW to simulate the constructed wetland (CW) conditions. The model was calibrated based on the BOD5 and TN degradation constants. The model indicated that most of BOD and TN (88 and 92%, respectively) were removed through biological activity followed by adsorption. It was also observed that the evapotranspiration was seen to have a smaller impact. An additional data series of effluent BOD and TN was used for model validation. The residual analysis of the calibrated model showed a relatively random pattern, indicating a decent fit. Thus, the VS2DTI was found to be a useful tool for CW simulation.

  10. Determinations of Microbiological Activity, Organic Matter and Nitrogen Forms in Soil in the Different Soil Tillage, Fallow-Wheat....

    OpenAIRE

    ADAK, M. Sait

    1998-01-01

    According to experimental results of two crop rotation cycles higher soil microbiological activities (i.e.b-Glucosidase and dehydrogenase activity) were obtained from soil samples of winter lentil plots in comparision to fallow plots. Highest activities of both parameters were found in the upper soil layer of 0-20 cm depth. The observed differences between lentil and fallow disap-peared during the following cropping season. Similar tendencies were also obtained for organic matter, total n...

  11. Nocturnal isoprene oxidation over the Northeast United States in summer and its impact on reactive nitrogen partitioning and secondary organic aerosol

    Directory of Open Access Journals (Sweden)

    S. S. Brown

    2009-05-01

    Full Text Available Isoprene is the largest single VOC emission to the atmosphere. Although it is primarily oxidized photochemically during daylight hours, late-day emissions that remain in the atmosphere at sunset undergo oxidation by NO3 in regionally polluted areas with large NOx levels. A recent aircraft study examined isoprene and its nocturnal oxidants in a series of night flights across the Northeast US, a region with large emissions of both isoprene and NOx. Substantial amounts of isoprene that were observed after dark were strongly anticorrelated with measured NO3 and were the most important factor determining the lifetime of this radical. The products of photochemical oxidation of isoprene, methyl vinyl ketone and methacrolein, were more uniformly distributed, and served as tracers for the presence of isoprene at sunset, prior to its oxidation by NO3. A determination of the mass of isoprene oxidized in darkness showed it to be a large fraction (>20% of emitted isoprene. Organic nitrates produced from the NO3+isoprene reaction, though not directly measured, were estimated to account for 2–9% of total reactive nitrogen. The mass of isoprene oxidized by NO3 was comparable to and correlated with the organic aerosol loading for flights with relatively low organic aerosol background. The contribution of nocturnal isoprene oxidation to secondary organic aerosol was determined in the range 1–17%, and isoprene SOA mass derived from NO3 was calculated to exceed that due to OH by approximately 50%.

  12. Learning-by-Being-Acquired

    DEFF Research Database (Denmark)

    Colombo, Massimo Gaetano; Moreira, Solon; Rabbiosi, Larissa

    2016-01-01

    of new teams with both inventors of the acquiring and acquired firms-and assess the impact of this integration action in the period that immediately follows the acquisition. Drawing on social identity and self-categorization theories, we argue that R&D team reorganization increases the acquired inventors......’ use of the prior stock of technological knowledge of the acquiring firm after the acquisition. Furthermore, this effect is enhanced if the focal acquired inventor has high relative innovation ability but is weakened for acquired inventors with high ingroup collaborative strength. We construct a sample...

  13. Learning-By-Being-Acquired

    DEFF Research Database (Denmark)

    Colombo, Massimo G.; Moreira, Solon; Rabbiosi, Larissa

    In this paper we study post-acquisition integration in terms of R&D team reorganization—i.e., the creation of new teams with both inventors of the acquiring and acquired firms—and assess its impact on knowledge transfer in the period that follows the acquisition. Drawing on social identity and self......-categorization theories, we argue that R&D team reorganization increases the acquired inventors’ use of the prior stock of technological knowledge of the acquiring firm after the acquisition. Furthermore, this effect is enhanced if acquired inventors have higher innovation ability relative to their acquiring peers...

  14. Application of Organic Carbon and Nitrogen Stable Isotope and C/N Ratios as Source Indicators of Organic Matter Provenance in Estuarine Systems: Evidence from the Tay Estuary, Scotland

    Science.gov (United States)

    Thornton, S. F.; McManus, J.

    1994-03-01

    The source of particulate organic matter (POM) in lacustrine and estuarine sediments from the Tay River catchment has been evaluated using stable carbon and nitrogen isotope and elemental C/N ratios. The δ 13C, δ 15N and C/N compositions of POM from the two environments (respectively -25·4 to -28·0%, 0·2 to 4·0%, 12·17 to 19·5 and -23·2 to -26·6%, 2·6 to 10·6%, 9·03 to 15·71) were statistically distinct, enabling, by use of a simple two component mixing equation, assessment of the ability of each tracer to estimate the terrigenous flux to the estuarine organic matter pool. Estuarial mixing of terrigenous, indigenous estuarine and marine derived organics, recorded by δ 13C data, was only partly confirmed by equivalent δ 15N and C/N compositions which reflected greater control by organic matter diagenesis and biological processing. Limited data indicate sewage derived contributions are insignificant. Of the three tracers employed, only δ 13C ratios are reliable as provenance indicators. Both δ 15N and C/N ratios are limited because the original POM source signature may be lost or overprinted by biochemical alteration prior to and/or soon after deposition. The simultaneous application of these tracers provides substantially more information regarding the source, quality and turnover of sedimentary POM in these contrasting systems than could be achieved using one technique alone.

  15. Characteristics of C-, N-DBPs formation from nitrogen-enriched dissolved organic matter in raw water and treated wastewater effluent.

    Science.gov (United States)

    Chang, Huihsien; Chen, Chiayang; Wang, Genshuh

    2013-05-15

    The objective of this study is to clarify the relationships between the characteristics of dissolved organic nitrogen (DON) and disinfection by-products (DBPs) formation. Treated wastewater effluents from the Neihu wastewater treatment plant in Taipei City (TN) and source waters from the Tai Lake water treatment plant in Kinmen (KT) were evaluated. These water samples were fractionated to obtain 7 DON isolates with different characteristics. The DON isolates were freeze-dried and re-dissolved to different DON fraction solutions containing 10 mg-C/L of non-purgeable dissolved organic carbon (NPDOC). The DBPs formation potentials (DBPFPs) (trihalomethanes (THMs), haloacetic acids (HAAs), and nitrosamines) of different DON fraction solutions were then assessed with chlorine and monochloramine treatments. After fractionation schemes, mass concentrations of dried DON-enriched isolates ranged from 0.2 to 46.4 mg/L. Both TN effluents and KT raw waters had similar compositions of DON fractions except for the amounts of amphiphilic bases/neutrals (AMPB/N) isolates: hydrophobic acids (HPOA) > hydrophilic acids/neutrals (HPIA/N) > AMPB/N of KT raw waters > hydrophilic bases (HPIB) > amphiphilic acids (AMPA) > hydrophobic bases/neutrals (HPOB/N) > AMPB/N of TN effluents > amino acids (AA). For carbonated DBPs (C-DBPs), AA fraction treated with NaOCl formed the greatest amounts of C-DBPs (up to 1258.2 μg/L of THMs and 1140.6 μg/L of HAAs). For nitrogenated DBPs (N-DBPs), the AMPB/N fraction (DON = 1.4 mg-N/L) treated with NH2Cl was the most important precursor to form N-nitrosodimethylamine (NDMA) and generated up to 9238.0 ng/L of NDMA from KT raw water. Taking both DBP formation and organic composition into account, the HPOA (31.9%-38.4%)/HPIA/N (17.6%-35.7%) fractions and AMPB/N fraction (38.4%-93.9%) were the most important contributors to the overall C-DBPFPs and N-DBPFPs, respectively.

  16. Transition-metal-catalyzed C-N bond forming reactions using organic azides as the nitrogen source: a journey for the mild and versatile C-H amination.

    Science.gov (United States)

    Shin, Kwangmin; Kim, Hyunwoo; Chang, Sukbok

    2015-04-21

    Owing to the prevalence of nitrogen-containing compounds in functional materials, natural products and important pharmaceutical agents, chemists have actively searched for the development of efficient and selective methodologies allowing for the facile construction of carbon-nitrogen bonds. While metal-catalyzed C-N cross-coupling reactions have been established as one of the most general protocols for C-N bond formation, these methods require starting materials equipped with functional groups such as (hetero)aryl halides or their equivalents, thus generating stoichiometric amounts of halide salts as byproducts. To address this aspect, a transition-metal-catalyzed direct C-H amination approach has emerged as a step- and atom-economical alternative to the conventional C-N cross-coupling reactions. However, despite the significant recent advances in metal-mediated direct C-H amination reactions, most available procedures need harsh conditions requiring stoichiometric external oxidants. In this context, we were curious to see whether a transition-metal-catalyzed mild C-H amination protocol could be achieved using organic azides as the amino source. We envisaged that a dual role of organic azides as an environmentally benign amino source and also as an internal oxidant via N-N2 bond cleavage would be key to develop efficient C-H amination reactions employing azides. An additional advantage of this approach was anticipated: that a sole byproduct is molecular nitrogen (N2) under the perspective catalytic conditions. This Account mainly describes our research efforts on the development of rhodium- and iridium-catalyzed direct C-H amination reactions with organic azides. Under our initially optimized Rh(III)-catalyzed amination conditions, not only sulfonyl azides but also aryl- and alkyl azides could be utilized as facile amino sources in reaction with various types of C(sp(2))-H bonds bearing such directing groups as pyridine, amide, or ketoxime. More recently, a new

  17. Advances in studies on dissolved organic nitrogen in terrestrial ecosystems%陆地生态系统可溶性有机氮研究进展

    Institute of Scientific and Technical Information of China (English)

    刘艳; 周国逸; 刘菊秀

    2005-01-01

    可溶性有机氮(dissolved organic nitrogen DON)的流动是陆地生态系统氮循环的重要组成部分.本文就陆地生态系统DON的来源、组成、性质;森林生态系统DON的流动、季节动态以及DON在氮循环中的地位等方面作了概括和探讨.今后的陆地生态系统DON的研究应该集中在以下几个方面:确定陆地生态系统中DON的各分室DON的浓度、流量;DON的源与汇问题;量化不同生态系统中DON库的大小和组成;研究DON在氮的矿化、微生物的固持、以及植物吸收等氮循环过程中的地位;对比研究DON与DOC(dissolved organic carbon)的动态差别;探讨DON与植物营养和碳积累的关系等.

  18. Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4+-N and NO3--N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4+-N concentrations by 19.1%-24.3%, but reduced the mean NO3--N concentrations by 44.9%-56.6% in the leachate,under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%-30.9%, 14.9%-43.5%, and 14.7%-31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP.It is proposed that DMPP has the potential to either reduce NO3--N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.

  19. Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system.

    Science.gov (United States)

    Li, Hua; Liang, Xinqiang; Chen, Yingxu; Lian, Yanfeng; Tian, Guangming; Ni, Wuzhong

    2008-01-01

    DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4(+)-N and NO3(-)-N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4(+)-N concentrations by 19.1%--24.3%, but reduced the mean NO3(-)-N concentrations by 44.9%--56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%--30.9%, 14.9%--43.5%, and 14.7%--31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3(-)-N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.

  20. EARTHWORM PONTOSCOLEXCORETHRURUS AND NITROGEN MINERALIZATION RATE IN INCUBATION EXPERIMENT WITH DIFFERENT QUALITY ORGANIC MATTERS FROM SUGARAGRO-INDUSTRY WASTE

    Directory of Open Access Journals (Sweden)

    J.B.Naik

    2014-02-01

    Full Text Available To investigate the effect of earthworm inoculation on N mineralization rates of different quality organic matters from sugar agro-industry waste, we conducted a green house incubation experiment for 14 weeks in pots containing 7 kg dry soil. There are 12 treatment combinations.Factor I waswith (P and without inoculation of P.corethrurus (N. Factor II was the type of OM which consisted of six levels: (1 without application of OM (control, (2 cow manure (CM, (3 filter cake (FC, (4 sugarcane trash (ST, (5 a mixture of CM + FC and (6 a mixture of CM + ST. The treatments were arranged in a factorial randomized block design with three replications. The amount of released N-NH4 +and N-NO3 - or mineral N was measured during incubation time from 1, 2, 4, 8, and 14 weeks after inoculation of earthworms. There was a significant effect of earthworm inoculation on N mineralization rate of different quality organic matters. Overall, rate of net N mineralization were higher in treatments with earthworm inoculation than without earthworm inoculation and the magnitude of the increase appears to dependent on the quality of organic matters. The largest difference were seen on ST and CM+ST treatments with the increase by 90 % and 157 % and the constant of N mineralization rate by 0.0147 and 0.0180 week-1 for the treatment with earthwormsinoculation.These results suggested that application of sugar agro-industry waste although having low quality can improve soil N availability in sugarcane land when aided by P.corethrurus activity.

  1. Intra-annual variability of carbon and nitrogen stable isotopes in suspended organic matter in waters of the western continental shelf of India

    Directory of Open Access Journals (Sweden)

    M. V. Maya

    2011-04-01

    Full Text Available The δ13C and δ15N of water-column suspended particulate organic matter (SPOM, elemental carbon and nitrogen concentrations, and C/N ratios in SPOM, along with ancillary chemical and biological variables including phytoplankton pigment abundance, were determined every month, with the partial exception of the southwest (SW monsoon period, from March 2007 to September 2008 at a fixed site located off Goa (central west coast of India. The results reveal significant shifts in isotopic signatures, especially δ15N, of SPOM before and after the onset of the SW monsoon. Very low δ15N values, reaching a minimum of −4.17‰, are found during the pre-monsoon period. Although the average δ15N values for the SW monsoon (6.55‰ and post-monsoon (6.19‰ are substantially higher, these values are lower than expected from a region that experiences intense water-column denitrification, as well as those reported previously from the open Arabian Sea. Our results provide the first direct evidence for the addition of substantial amounts of isotopically light nitrogen by the diazotrophs, especially Trichodesmium, in the region. The δ15N of SPOM is generally lower than the mean value (7.38‰ for surficial sediments in the region, presumably because of diagenetic enrichment. The results support the notion that sedimentary δ15N may not necessarily reflect denitrification intensity in the overlying waters due to diverse sources of nitrogen and variability of its isotopic composition. The observed intra-annual variability of δ13C of SPOM is small (seasonal averages: pre-monsoon: −21.40‰, SW monsoon: −20.41‰ and post-monsoon: −22.15‰. Phytoplankton production and probably species composition could drive the observed changes. Occasional shifts in δ13C toward more negative values are suggestive of terrestrial inputs, but by and large the SPOM in

  2. Spatial distribution of soil organic carbon and total nitrogen based on GIS and geostatistics in a small watershed in a hilly area of northern China.

    Science.gov (United States)

    Peng, Gao; Bing, Wang; Guangpo, Geng; Guangcan, Zhang

    2013-01-01

    The spatial variability of soil organic carbon (SOC) and total nitrogen (STN) levels is important in both global carbon-nitrogen cycle and climate change research. There has been little research on the spatial distribution of SOC and STN at the watershed scale based on geographic information systems (GIS) and geostatistics. Ninety-seven soil samples taken at depths of 0-20 cm were collected during October 2010 and 2011 from the Matiyu small watershed (4.2 km(2)) of a hilly area in Shandong Province, northern China. The impacts of different land use types, elevation, vegetation coverage and other factors on SOC and STN spatial distributions were examined using GIS and a geostatistical method, regression-kriging. The results show that the concentration variations of SOC and STN in the Matiyu small watershed were moderate variation based on the mean, median, minimum and maximum, and the coefficients of variation (CV). Residual values of SOC and STN had moderate spatial autocorrelations, and the Nugget/Sill were 0.2% and 0.1%, respectively. Distribution maps of regression-kriging revealed that both SOC and STN concentrations in the Matiyu watershed decreased from southeast to northwest. This result was similar to the watershed DEM trend and significantly correlated with land use type, elevation and aspect. SOC and STN predictions with the regression-kriging method were more accurate than those obtained using ordinary kriging. This research indicates that geostatistical characteristics of SOC and STN concentrations in the watershed were closely related to both land-use type and spatial topographic structure and that regression-kriging is suitable for investigating the spatial distributions of SOC and STN in the complex topography of the watershed.

  3. Restoration of nutrient-rich forestry-drained peatlands poses a risk for high exports of dissolved organic carbon, nitrogen, and phosphorus.

    Science.gov (United States)

    Koskinen, Markku; Tahvanainen, Teemu; Sarkkola, Sakari; Menberu, Meseret Walle; Laurén, Ari; Sallantaus, Tapani; Marttila, Hannu; Ronkanen, Anna-Kaisa; Parviainen, Miia; Tolvanen, Anne; Koivusalo, Harri; Nieminen, Mika

    2017-05-15

    Restoration impact of forestry-drained peatlands on runoff water quality and dissolved organic carbon (DOC) and nutrient export was studied. Eight catchments were included: three mesotrophic (one undrained control, two treatments), two ombrotrophic (one drained control, one treatment) and three oligotrophic catchments (one undrained control, two treatments). Three calibration years and four post-restoration years were included in the data from seven catchments, for which runoff was recorded. For one mesotrophic treatment catchment only one year of pre-restoration and two years of post-restoration water quality data is reported. Restoration was done by filling in and damming the ditches. Water samples were collected monthly-biweekly during the snow-free period; runoff was recorded continuously during the same period. Water quality was estimated for winter using ratios derived from external data. Runoff for non-recorded periods were estimated using the FEMMA model. A high impact on DOC, nitrogen (N) and phosphorus (P) was observed in the mesotrophic catchments, and mostly no significant impact in the nutrient-poor catchments. The DOC load from one catchment exceeded 1000kg (restored-ha)(-1) in the first year; increase of DOC concentration from 50 to 250mgl(-1) was observed in the other mesotrophic treatment catchment. Impact on total nitrogen export of over 30kg (restored-ha)(-1) was observed in one fertile catchment during the first year. An impact of over 5kg (restored-ha)(-1) on ammonium export was observed in one year in the mesotrophic catchment. Impact on P export from the mesotrophic catchment was nearly 5kg P (restored-ha)(-1) in the first year. The results imply that restoration of nutrient-rich forestry-drained peatlands poses significant risk for at least short term elevated loads degrading the water quality in receiving water bodies. Restoration of nutrient-poor peatlands poses a minor risk in comparison. Research is needed regarding the factors behind

  4. Effects of Elevated CO2 Concentration on the Biomasses and Nitrogen Concentrations in the Organs of Sainfoin(Onobrychis viciaefolia Scop.)

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zheng-chao; SHANGGUAN Zhou-ping

    2009-01-01

    In forage grasses,the nitrogen concentration is directly related to the nutritional value.The studies examined the hypothesis that global elevation of CO2 concentration probably affects the biomass,nitrogen(N)concentration,and allocation and distribution patterns in the organs of forage grasses.While sainfoin(Onobrychis viciaefolia Scop.)seedlings grew on a low nutrient soil in closed chambers for 90 days,they were exposed to two CO2 concentrations(ambient or ambient+350μmol mol-1 CO2)without adding nutrients to them.After 90 days exposure to CO2,the biomasses of leaves,stems,and roots,and N concentrations and contents of different parts were measured.Compared with the ambient CO2 concentration,the elevated CO2 concentration increased the total dry matter by 25.07%,mainly due to the root and leaf having positive response to the elevated CO2 concentration.However,the elevated CO2 concentration did not change the proportions of the dry matters in different parts and the total plants compared with the ambient CO2 concentration.The elevated CO2 concentration lowered the N concentrations of the plant parts.Because the dry matter was higher,the elevated CO2 concentration had no effect on the N content in the plants compared to the ambient CO2 concentration.The elevated CO2 concentration promoted N allocations of the different parts significantly and increased N allocation of the underground part.The results have confirmed the previous suggestions that the elevated CO2 concentration stimulates plant biomass production and decreases the N concentrations of the plant parts.

  5. New organic reference materials for hydrogen, carbon, and nitrogen stable isotope-ratio measurements: caffeines, n-alkanes, fatty acid methyl esters, glycines, L-valines, polyethylenes, and oils.

    NARCIS (Netherlands)

    Bijma, Anita

    2016-01-01

    An international project developed, quality-tested, and determined isotope–δ values of 19 new organic reference materials (RMs) for hydrogen, carbon, and nitrogen stable isotope-ratio measurements, in addition to analyzing pre-existing RMs NBS 22 (oil), IAEA-CH-7 (polyethylene foil), and IAEA-600 (c

  6. New organic reference materials for hydrogen, carbon, and nitrogen stable isotope-ratio measurements : caffeines, n-alkanes, fatty acid methyl esters, glycines, L-valines, polyethylenes, and oils

    NARCIS (Netherlands)

    Schimmelmann, Arndt; Qi, Haiping; Coplen, Tyler B; Brand, Willi A; Fong, Jon; Meier-Augenstein, Wolfram; Kemp, Helen Felicity; Toman, Blaza; Ackermann, Annika; Assonov, Sergey; Aerts-Bijma, Anita; Brejcha, Ramona; Chikaraishi, Yoshito; Darwish, Tamim A; Elsner, Martin; Gehre, Matthias; Geilmann, Heike; Groening, Manfred; Hélie, Jean-François; Herrero-Martín, Sara; Meijer, Harro A J; Sauer, Peter E; Sessions, Alex Lee; Werner, Roland A

    2016-01-01

    An international project developed, quality-tested, and determined isotope-δ values of 19 new organic reference materials (RMs) for hydrogen, carbon, and nitrogen stable isotope-ratio measurements, in addition to analyzing pre-existing RMs NBS 22 (oil), IAEA-CH-7 (polyethylene foil), and IAEA-600 (c

  7. Identification of genotypic variation for nitrogen response in potato (Solanum tuberosum) under low nitrogen input circumstances

    NARCIS (Netherlands)

    Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P.C.

    2009-01-01

    Nitrogen is an essential nutrient for crop growth. The demand for nitrogen in the potato crop is relatively high. However, in organic farming nitrogen input is rather limited, compared with conventional farming. In this research nine potato varieties were tested at three nitrogen levels. Genotypic v

  8. Boron-nitrogen doped carbon scaffolding: organic chemistry, self-assembly and materials applications of borazine and its derivatives.

    Science.gov (United States)

    Bonifazi, Davide; Fasano, Francesco; Lorenzo-Garcia, M Mercedes; Marinelli, Davide; Oubaha, Hamid; Tasseroul, Jonathan

    2015-10-25

    Discovered by Stock and Pohland in 1926, borazine is the isoelectronic and isostructural inorganic analogue of benzene, where the C[double bond, length as m-dash]C bonds are substituted by B-N bonds. The strong polarity of such heteroatomic bonds widens the HOMO-LUMO gap of the molecule, imparting strong UV-emitting/absorption and electrical insulating properties. These properties make borazine and its derivatives valuable molecular scaffolds to be inserted as doping units in graphitic-based carbon materials to tailor their optoelectronic characteristics, and specifically their semiconducting properties. By guiding the reader through the most significant examples in the field, in this feature paper we describe the past and recent developments in the organic synthesis and functionalisation of borazine and its derivatives. These boosted the production of a large variety of tailored derivatives, broadening their use in optoelectronics, H2 storage and supramolecular functional architectures, to name a few.

  9. Assessing the Influence of Summer Organic Fertilization Combined with Nitrogen Inhibitor on a Short Rotation Woody Crop in Mediterranean Environment

    Directory of Open Access Journals (Sweden)

    Anita Maienza

    2014-01-01

    Full Text Available The European Union Directive 91/676/EEC, known as Nitrates Directive, has dictated basic agronomic principles regarding the use of animal manure source as well as livestock and waste waters from small food companies. The use of nitrification inhibitors together with animal effluents as organic fertilizers could be beneficial for nutrient recycling, plant productivity, and greenhouse gas emission and could offer economic advantages as alternative to conventional fertilizers especially in the Mediterranean region. The aim of the present study was to investigate differences in plant productivity between bovine effluent treatments with (or without addition of a nitrification inhibitor (3,4 DMPP in a short rotation woody crop system. Results of the field experiment carried out in a Mediterranean dry environment indicated that the proposed strategy could improve tree growth with indirect, beneficial effects for agroforestry systems.

  10. Surgical treatment of acquired tracheocele.

    Science.gov (United States)

    Porubsky, Edward A; Gourin, Christine G

    2006-06-01

    Acquired tracheoceles are rare clinical entities that can cause a variety of chronic and recurrent aerodigestive tract symptoms. The management of acquired tracheoceles is primarily conservative, but surgical intervention may be indicated for patients with refractory symptoms. We present a case of acquired tracheocele and describe a method of successful surgical management.

  11. Synergistic effect of oxygen vacancy and nitrogen doping on enhancing the photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3} nanosheets with exposed {0 0 1} facets for the degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yafei [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Zhu, Gangqiang, E-mail: zgq2006@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Hojamberdiev, Mirabbos [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Department of Natural and Mathematic Sciences, Turin Polytechnic University in Tashkent, Kichik Halqa Yo’li 17, Tashkent 100095 (Uzbekistan); Gao, Jianzhi [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Hao, Jing [Xi' an Rejee Industry Development Co., Ltd., Xi’an 710016 (China); Zhou, Jianping; Liu, Peng [School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China)

    2016-05-15

    Highlights: • Nitrogen-doped Bi{sub 2}O{sub 2}CO{sub 3} flower-like microstructures were synthesized by hydrothermal method. • Surface oxygen vacancy were obtained by irradiating the nitrogen-doped Bi{sub 2}O{sub 2}CO{sub 3} with UV light. • Photocatalytic activity was studied by degrading Rhodamine B. • A synergistic effect between oxygen vacancy and nitrogen doping in Bi{sub 2}O{sub 2}CO{sub 3}. - Abstract: Single-crystalline bare Bi{sub 2}O{sub 2}CO{sub 3} (BOC) nanosheets with exposed {0 0 1} facets and nitrogen-doped Bi{sub 2}O{sub 2}CO{sub 3} (NBOC) flower-like microstructures were synthesized by a simple hydrothermal method. The nitrogen-doped Bi{sub 2}O{sub 2}CO{sub 3} flower-like microstructures with oxygen vacancy (UV-NBOC) were obtained by irradiating the NBOC microstructures with UV light for 2 h in ethanol. The UV–vis diffuse reflectance spectra showed that the NBOC and UV-NBOC nanosheets exhibit an obvious red shift in light absorption band compared with the pure BOC nanosheets. Rhodamine B (RhB) was chosen as a model organic pollutant to verify the influence of oxygen vacancy and nitrogen doping on the photocatalytic activity of Bi{sub 2}O{sub 2}CO{sub 3} under simulated solar light irradiation. Judging from the kinetics of RhB photodegradation over the synthesized samples, a synergistic effect between oxygen vacancy and nitrogen doping was found with a remarkable increase (more than 10 and 2 times) in the photocatalytic activity of UV-NBOC compared with BOC and NBOC, respectively. Moreover, the UV-NBOC also exhibited an excellent cyclability and superior photocatalytic activity toward degradation of other organic pollutants (methylene blue, Congo red, Bisphenol A) under simulated solar light irradiation.

  12. Characteristics of Nitrogen Balances of Large-scale Stock Farms and Reduction of Environmental Nitrogen Loads

    Science.gov (United States)

    Hattori, Toshihiro; Takamatsu, Rieko

    We calculated nitrogen balances on farm gate and soil surface on large-scale stock farms and discussed methods for reducing environmental nitrogen loads. Four different types of public stock farms (organic beef, calf supply and daily cows) were surveyed in Aomori Prefecture. (1) Farm gate and soil surface nitrogen inflows were both larger than the respective outflows on all types of farms. Farm gate nitrogen balance for beef farms were worse than that for dairy farms. (2) Soil surface nitrogen outflows and soil nitrogen retention were in proportion to soil surface nitrogen inflows. (3) Reductions in soil surface nitrogen retention were influenced by soil surface nitrogen inflows. (4) In order to reduce farm gate nitrogen retention, inflows of formula feed and chemical fertilizer need to be reduced. (5) In order to reduce soil surface nitrogen retention, inflows of fertilizer need to be reduced and nitrogen balance needs to be controlled.

  13. Changes in soil organic carbon and total nitrogen in croplands converted to walnut-based agroforestry systems and orchards in southeastern Loess Plateau of China.

    Science.gov (United States)

    Lu, Sen; Meng, Ping; Zhang, Jinsong; Yin, Changjun; Sun, Shiyou

    2015-11-01

    Limited information is available on the effects of agroforestry system practices on soil properties in the Loess Plateau of China. Over the last decade, a vegetation restoration project has been conducted in this area by converting cropland into tree-based agroforestry systems and orchards to combat soil erosion and degradation. The objective of the present study was to determine the effects of land use conversion on soil organic carbon and total nitrogen in southeastern Loess Plateau. The experiment included three treatments: walnut intercropping system (AF), walnut orchard (WO), and traditional cropland (CR). After 7 years of continual management, soil samples were collected at 0-10, 10-30, and 30-50-cm depths for three treatments, and soil organic carbon (SOC) and total nitrogen (TN) were measured. Results showed that compared with the CR and AF treatments, WO treatment decreased both SOC and TN concentrations in the 0-50-cm soil profile. However, similar patterns of SOC and TN concentrations were observed in the AF and CR treatments across the entire profile. The SOC stocks at 0-50-cm depth were 5.42, 5.52, and 4.67 kg m(-2) for CR, AF, and WO treatments, respectively. The calculated TN stocks at 0-50-cm depth were 0.63, 0.62, and 0.57 kg m(-2) for CR, AF, and WO treatments, respectively. This result demonstrated that the stocks of SOC and TN in WO were clearly lower than those of AF and CR and that the walnut-based agroforestry system was more beneficial than walnut monoculture in terms of SOC and TN sequestration. Owing to the short-term intercropping practice, the changes in SOC and TN stocks were slight in AF compared with those in CR. However, a significant decrease in SOC and TN stocks was observed during the conversion of cropland to walnut orchard after 7 years of management. We also found that land use types had no significant effect on soil C/N ratio. These findings demonstrated that intercropping between walnut rows can potentially maintain

  14. Late Holocene stable carbon and nitrogen isotopic variation of bulk organic matter deposited in Blackwood Sinkhole, Abaco, The Bahamas

    Science.gov (United States)

    Tamalavage, A.; van Hengstum, P. J.; Louchouarn, P.; Fall, P. L.; Donnelly, J. P.

    2015-12-01

    In the modern climate of the Bahamas, a latitudinal precipitation gradient only allows Pine (Pinus caribaea var. bahamensis) dominated forests to exist on the more mesic (humid) northern islands (Abaco, Andros, New Providence, Grand Bahamas). Previous research suggests that the northern Bahamas underwent dramatic environmental changes in the late Holocene (e.g., waves of human arrival, shifts in terrestrial vegetation and animal extinctions). However, disentangling the timing and relative forcing (climatic vs. anthropogenic) of these changes has proven challenging without high-resolution terrestrial climate records. Recently, a late Holocene decadal to multi-decadal laminated sedimentary record was recovered from Blackwood Sinkhole, on Abaco Island. The bottom of the sinkhole is characterized by anoxic, saline groundwater, while the upper, brackish meteoric lens provides a habitat to fish, algae and other organisms. Here, we present δ13Corg and δ15Norg values of bulk organic matter (OM) taken every cm of the 110 cm core to help elucidate changes in the chemical composition of the source of OM reaching the anoxic sediments of the sinkhole. δ13Corg values change at 812 Cal yrs BP (2s: 931-681 Cal yrs BP, 31.7 cm depth) from -30.5 ± 1.6‰ in the lower 80 cm of the core to -27.6 ± 1.2‰ in the upper 30 cm. There is a synchronous change from more enriched δ15N values, 3.7 ± 1.1‰, in the lower portion of the core, to lower δ15N values (1.9 ± .5‰), in the upper portion of the core. A pollen-based reconstruction of terrestrial vegetation from the same core indicates that these isotopic shifts are concomitant with a shift from a dominance of Arecaceae (Palms) and tropical dry hardwoods below 30 cm, to Pinus and Conocarpus predominance above 30 cm. These results indicate that the source of sedimentary OM deposited into the sinkhole changed coherently with regional landscape change. Biomarker analyses will be used to further identify the role of autochthonous

  15. Evaluation of Post-Harvest Organic Carbon Amendments as a Strategy to Minimize Nitrogen Losses in Cole Crop Production

    Directory of Open Access Journals (Sweden)

    Laura L. Van Eerd

    2013-02-01

    Full Text Available Cole crops (Brassica vegetables can pose a significant risk for N losses during the post-harvest period due to substantial amounts of readily mineralizable N in crop residues. Amending the soil with organic C has the potential to immobilize N and thereby reduce the risk for N losses. Four field trials were conducted to determine the effects of organic C amendments (OCA on N dynamics and spring wheat (Triticum durum L. harvest parameters proceeding early- and late-broccoli (Brassica olecerea var italica L. systems in 2009 and 2010. The experimental controls represented the traditional grower practice of incorporated broccoli crop residue (CR-control and the pre-plant application of N fertilizer (CRN-control to subsequent spring wheat. Alternative practices were compared to the controls, which included broccoli crop residue removal (CR-removal, an oat (Avena sativa L. cover crop (CC-oat, and three different OCA of wheat straw (OCA-straw, yard waste (OCA-yard, or used cooking oil (OCA-oil. The treatments, which demonstrated reduced autumn soil mineral N (SMN concentrations after broccoli harvest, relative to the CR-control, were CR-removal, OCA-straw, and OCA-oil. Although CR-removal and OCA-straw indicated a reduced potential for autumn soil N losses in the early-broccoli system, these practices are not recommended for growers because subsequent spring wheat yield and profit margins were reduced compared to the CR- and CRN-controls. The OCA-oil reduced autumn SMN concentrations by 53 to 112 kg N ha−1 relative to the CR-control after both early- and late-broccoli harvest, suggesting a larger potential for reduced autumn soil N losses, compared to all other treatments. No detrimental effects resulted from the OCA-oil treatment on the subsequent spring yield or grain N. The OCA-oil reduced spring wheat profit margins relative to the CR-control, like the OCA-straw and CR-removal treatments, however profit margins were similar between the OCA-oil and

  16. Chlorinated and nitrogenous disinfection by-product formation from ozonation and post-chlorination of natural organic matter surrogates.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Rifai, Omar; Ali, Hussain; Graham, Nigel J D

    2014-09-01

    Ozonation before chlorination is associated with enhanced formation of chloropicrin, a halonitromethane disinfection by-product (DBP), during drinking water treatment. In order to elucidate reasons for this, five natural organic matter (NOM) surrogates were treated using both chlorination and ozonation-chlorination under controlled laboratory conditions. Selected surrogates comprised two phenolic compounds, two free amino acids and one dipeptide; these were resorcinol, 3-aminophenol, L-aspartic acid, β-alanine and ala-ala, respectively. Quantified DBPs included chloropicrin, chloroform, dichloroacetonitrile and trichloroacetonitrile. Relative to chlorination alone, increases in the formation of chloropicrin from ozonation-chlorination varied from 138% for 3-aminophenol to 3740% for ala-ala for the four amine surrogates. This indicates that ozone is more effective than chlorine in mediating a rate-limiting oxidation step in chloropicrin formation, most plausibly involving conversion of an amine group to a nitro group. While both hydrophilic and hydrophobic surrogates acted as chloropicrin precursors, ala-ala was the most reactive precursor following ozonation-chlorination. Since peptides are far commoner in drinking water sources than free amino acids, further research into chemical oxidation of these species by ozone and chlorine is recommended. In contrast, oxidation with ozone prior to chlorination reduced chloroform formation moderately for the two phenolic compounds.

  17. ASE extraction method for simultaneous carbon and nitrogen stable isotope analysis in soft tissues of aquatic organisms

    Energy Technology Data Exchange (ETDEWEB)

    Bodin, Nathalie [ISM/LPTC, UMR 5255 CNRS, Universite de Bordeaux 1, 351 Cours de la Liberation, 33405 Talence (France); CRH, UMR 212 EME, Institut de Recherche et de Developpement, Av Jean Monnet BP171, 34203 Sete (France); Budzinski, Helene, E-mail: h.budzinski@ism.u-bordeaux1.fr [ISM/LPTC, UMR 5255 CNRS, Universite de Bordeaux 1, 351 Cours de la Liberation, 33405 Talence (France); Le Menach, Karyn; Tapie, Nathalie [ISM/LPTC, UMR 5255 CNRS, Universite de Bordeaux 1, 351 Cours de la Liberation, 33405 Talence (France)

    2009-06-08

    Since lipids are depleted in {sup 13}C relative to proteins and carbohydrates, variations in lipid composition among species and within individuals significantly influence {delta}{sup 13}C and may result in misleading ecological interpretations. Whereas lipid extraction before IRMS analysis constitutes a way of stable isotope result lipid-normalisation, such a procedure was given up because of the un-controlled effects of the methods used (i.e., 'Bligh and Dyer', Soxhlet, etc.) on {delta}{sup 15}N. The aim of this work was to develop a simple, rapid and efficient lipid extraction method allowing for simultaneous C and N stable isotope analysis in the biological soft tissues of aquatic organisms. The goal was to be free from the lipid influence on {delta}{sup 13}C values without interfering with {delta}{sup 15}N values. For that purpose, the modern automated pressurized liquid extraction technique ASE (accelerated solvent extraction) was selected. Eel muscles representative of a broad range of fat contents were extracted via ASE by using different semi-polar solvents (100% dichloromethane and 80% n-hexane/20% acetone) and by operating at different temperature (ambient temperature and 100 deg. C) and pressure (750 and 1900 psi) conditions. The results were discussed in terms of lipid extraction efficiency as well as {delta}{sup 13}C and {delta}{sup 15}N variability.

  18. Cryptogenic Organizing Pneumonia Repeatedly Misdiagnosed as Community Acquired Pneumonia%隐源性机化性肺炎反复误诊为社区获得性肺炎

    Institute of Scientific and Technical Information of China (English)

    梅周芳; 钱凌; 都勇; 施劲东; 何炜; 揭志军

    2015-01-01

    Objective To study the diagnosis and treatment of cryptogenic organizing pneumonia (COP), so as to re-duce misdiagnosis rate. Methods Clinical data of one case of community acquired pneumonia misdiagnosed as COP in our hospital was retrospectively analyzed, with a review of literature. Results The patient had been hospitalized 5 months before for lung exudation. CT scanning in a local hospital supported diagnosis of CAP and anti-infection therapy failed to respond. Our hospital chest CT scan showed multiple exudation in both lungs; bronchoscopy checked patency of every lumen; B type ul-trasound revealed no enlarged superficial lymph nodes; lung biopsy and pathological examination showed COP, the patient's symptoms were significantly relieved after high dose glucocorticoid pulse therapy for one week and at the same time, most le-sions were absorbed. Conclusion For multiple pulmonary exudative consolidation patients with long course of disease, re-fractory to conventional anti infection treatment, especially for the glucocorticoid sensitivity, COP should be considered and fi-beroptic bronchoscopy or CT guided percutaneous lung biopsy should be performed in order to reduce the misdiagnosis and mis-treatment rates.%目的:探讨隐源性机化性肺炎(cryptogenic organizing pneumonia, COP)的诊治要点,以减少误诊。方法回顾分析我科收治的1例误诊为社区获得性肺炎(community acquired pneumonia, CAP)的 COP 临床资料,并复习相关文献。结果本例因发现双肺反复渗出性病灶5个月就诊。病程中多次就诊当地医院行胸部 CT 扫描诊断为CAP,反复予抗感染治疗无效。入我院后查血常规未见明显异常,胸部 CT 检查示两肺上叶、右肺下叶多发炎性病灶;纤维支气管镜未见异常;B 超检查未见全身浅表淋巴结增大;肿瘤标志物检测、痰病原学及感染生物标志物检查均(-)。后行 CT 引导下经皮肺穿刺活检病理检查,并结

  19. Acquiring specific interpreting competence

    Directory of Open Access Journals (Sweden)

    Jana Zidar Forte

    2012-12-01

    Full Text Available In postgraduate interpreter training, the main objective of the course is to help trainees develop various competences, from linguistic, textual and cultural competence, to professional and specific interpreting competence. For simultaneous interpreting (SI, the main focus is on mastering the SI technique and strategies as well as on developing and strengthening communicative skills, which is discussed and illustrated with examples in the present paper. First, a brief overview is given of all the necessary competences of a professional interpreter with greater emphasis on specific interpreting competence for SI. In the second part of the paper, various approaches are described in terms of acquiring specific skills and strategies, specifically through a range of exercises. Besides interpreting entire speeches, practical courses should also consist of targeted exercises, which help trainees develop suitable coping strategies and mechanisms (later on almost automatisms, while at the same time "force" them to reflect on their individual learning process and interpreting performance. This provides a solid base on which trained interpreters can progress and develop their skills also after joining the professional sphere.

  20. Role of Carbon Substrates Added in the Transformation of Surplus Nitrate to Organic Nitrogen in a Calcareous Soil

    Institute of Scientific and Technical Information of China (English)

    QIU Shao-Jun; JU Xiao-Tang; J.INGWERSEN; GUO Zi-De; C.F.STANGE; R.BISHARAT; T.STRECK

    2013-01-01

    Excessive amounts of nitrate have accumulated in many soils on the North China Plain due to the large amounts of chemical N fertilizers or manures used in combination with low carbon inputs.We investigated the potential of different carbon substrates added to transform soil nitrate into soil organic N (SON).A 56-d laboratory incubation experiment using the 15N tracer (K15NO3)technique was carried out to elucidate the proportion of SON derived from accumulated soil nitrate following amendment with glucose or maize straw at controlled soil temperature and moisture.The dynamics and isotopic abundance of mineral N (NO3-and NH4+) and SON and greenhouse gas (N2O and CO2) emissions during the incubation were investigated.Although carbon amendments markedly stimulated transformation of nitrate to newly formed SON,this was only a substitution effect of the newly formed SON with native SON because SON at the end of the incubation period was not significantly different (P > 0.05) from that in control soil without added C.At the end of the incubation period,amendment with glucose,a readily available C source,increased nitrate immobilization by 2.65 times and total N2O-N emission by 33.7 times,as compared with maize straw amendment.Moreover,the differences in SON and total N2O-N emission between the treatments with glucose and maize straw were significant (P < 0.05).However,the total N2O-N emission in the straw treatment was not significantly (P > 0.05) greater than that in the control.Straw amendment may be a potential option in agricultural practice for transformation of nitrate N to SON and minimization of N2O emitted as well as restriction of NO3-N leaching.

  1. Effects of tillage and nitrogen fertilizers on CH4 and CO2 emissions and soil organic carbon in paddy fields of central China.

    Directory of Open Access Journals (Sweden)

    Li Cheng-Fang

    Full Text Available Quantifying carbon (C sequestration in paddy soils is necessary to help better understand the effect of agricultural practices on the C cycle. The objective of the present study was to assess the effects of tillage practices [conventional tillage (CT and no-tillage (NT] and the application of nitrogen (N fertilizer (0 and 210 kg N ha(-1 on fluxes of CH(4 and CO(2, and soil organic C (SOC sequestration during the 2009 and 2010 rice growing seasons in central China. Application of N fertilizer significantly increased CH(4 emissions by 13%-66% and SOC by 21%-94% irrespective of soil sampling depths, but had no effect on CO(2 emissions in either year. Tillage significantly affected CH(4 and CO(2 emissions, where NT significantly decreased CH(4 emissions by 10%-36% but increased CO(2 emissions by 22%-40% in both years. The effects of tillage on the SOC varied with the depth of soil sampling. NT significantly increased the SOC by 7%-48% in the 0-5 cm layer compared with CT. However, there was no significant difference in the SOC between NT and CT across the entire 0-20 cm layer. Hence, our results suggest that the potential of SOC sequestration in NT paddy fields may be overestimated in central China if only surface soil samples are considered.

  2. Precise and economical dredging model of sediments and its field application: case study of a river heavily polluted by organic matter, nitrogen, and phosphorus.

    Science.gov (United States)

    Zhang, Rui; Zeng, Fan-Xin; Liu, Wu-Jun; Zeng, Raymond J; Jiang, Hong

    2014-06-01

    Environmental dredging is an efficient means to counteract the eutrophication of water bodies caused by endogenous release of nitrogen and/or phosphorus from polluted sediments. The huge operational cost and subsequent disposal cost of the dredged polluted sediments, as well as the adverse effect on the benthic environment caused by excessive dredging, make the currently adopted dredging methods unfavorable. Precise dredging, i.e., determining the dredging depth based on the pollution level, not only significantly decreases the costs but also leaves a uniform favorable environment for benthos. However, there is still no feasible process to make this promising method executable. Taking a river heavily polluted by organic compounds as an example, we proposed an executable precise dredging process, including sediment survey, model establishment, data interpolation, and calculation of dredging amount. Compared with the traditional dredging method, the precise one would save 16 to 45% of cost according to different pollutant removal demands. This precise dredging method was adopted by the National Water Project of China to treat the endogenous pollution of Nanfei River in 2010. This research provides a universal scientific and engineering basis for sediment dredging projects.

  3. Effect of Source-Sink Manipulation on Photosynthetic Characteristics of Flag Leaf and the Remobilization of Dry Mass and Nitrogen in Vegetative Organs of Wheat

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying-hua; SUN Na-na; HONG Jia-pei; ZHANG Qi; WANG Chao; XUE Qing-wu; ZHOU Shun-li; HUANG Qin; WANG Zhi-min

    2014-01-01

    The photosynthetic characteristics of lfag leaf and the accumulation and remobilization of pre-anthesis dry mass (DM) and nitrogen (N) in vegetable organs in nine wheat cultivars under different source-sink manipulation treatments including defoliation (DF), spike shading (SS) and half spikelets removal (SR) were investigated. Results showed that the SS treatment increased the photosynthetic rate (Pn) of lfag leaf in source limited cultivar, but had no signiifcant effect on sink limited cultivar. The SR treatment decreased the Pn of lfag leaf. Grain DM accumulation was limited by source in some cultivars, in other cultivars, it was limited by sink. Grain N accumulation was mainly limited by source supply. The contribution of pre-anthesis dry mass to grain yield from high to low was stem, leaf and chaff, while the contribution of pre-anthesis N to grain N from high to low was leaf, stem and chaff. Cultivars S7221 and TA9818 can increase the contribution of remobilization of DM and N to grain at the maximum ratio under reducing source treatments, which may be the major reason for these cultivars having lower decrease in grain yield and N content under reducing source treatments.

  4. Application of visible-light photocatalysis with nitrogen-doped or unmodified titanium dioxide for control of indoor-level volatile organic compounds.

    Science.gov (United States)

    Jo, Wan-Kuen; Kim, Jong-Tae

    2009-05-15

    The present study evaluated visible-light photocatalysis, applying an annular reactor coated with unmodified or nitrogen (N)-doped titanium dioxide (TiO(2)), to cleanse gaseous volatile organic compounds (VOCs) at indoor levels. The surface chemistry investigation of N-doped TiO(2) suggested that there was no significant residual of sulfate ions or urea species on the surface of the N-doped TiO(2). Under visible-light irradiation, the photocatalytic technique using N-doped TiO(2) was much superior to that for unmodified TiO(2) for the degradation of VOCs. Moreover, the degradation efficiency by a reactor coated with N-doped TiO(2) was well above 90% for four target compounds (ethyl benzene, o,m,p-xylenes), suggesting that this photocatalytic system can be effectively employed to cleanse these pollutants at indoor air quality (IAQ) levels. The degradation efficiency of all target compounds increased as the stream flow rate (SFR) decreased. For most target compounds, a reactor with a lower hydraulic diameter (HD) exhibited elevated degradation efficiency. The result on humidity effect suggested that the N-doped photocatalyst could be employed effectively to remove four target compounds (ethyl benzene, o,m,p-xylenes) under conditions of less humidified environments, including a typical indoor comfort range (50-60%). Consequently, it is suggested that with appropriate photocatalytic conditions, a visible-light-assisted N-doped photocatalytic system is clearly an important tool for improving IAQ.

  5. Protozoa enhance foraging efficiency of arbuscular mycorrhizal fungi for mineral nitrogen from organic matter in soil to the benefit of host plants.

    Science.gov (United States)

    Koller, Robert; Rodriguez, Alia; Robin, Christophe; Scheu, Stefan; Bonkowski, Michael

    2013-07-01

    Dead organic matter (OM) is a major source of nitrogen (N) for plants. The majority of plants support N uptake by symbiosis with arbuscular mycorrhizal (AM) fungi. Mineralization of N is regulated by microfauna, in particular, protozoa grazing on bacteria. We hypothesized that AM fungi and protozoa interactively facilitate plant N nutrition from OM. In soil systems consisting of an OM patch and a root compartment, plant N uptake and consequences for plant carbon (C) allocation were investigated using stable isotopes. Protozoa mobilized N by consuming bacteria, and the mobilized N was translocated via AM fungi to the host plant. The presence of protozoa in both the OM and root compartment stimulated photosynthesis and the translocation of C from the host plant via AM fungi into the OM patch. This stimulated microbial activity in the OM patch, plant N uptake from OM and doubled plant growth. The results indicate that protozoa increase plant growth by both mobilization of N from OM and by protozoa-root interactions, resulting in increased C allocation to roots and into the rhizosphere, thereby increasing plant nutrient exploitation. Hence, mycorrhizal plants need to interact with protozoa to fully exploit N resources from OM.

  6. Productivity and nutritional characteristics of ramie (Boehmeria nívea cv Myasaki in four cutting frequencies fertilized with mineral or organic nitrogen

    Directory of Open Access Journals (Sweden)

    Diorande Bianchini

    2010-01-01

    Full Text Available This work was conducted in the Development Research Unit, in Itapetininga (23º35'30