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Sample records for organic matter chemical

  1. Chemical Structure of Insoluble Organic Matter of Meteorites

    Science.gov (United States)

    Derenne, S.; Robert, F.; Binet, L.; Gourier, D.; Rouzaud, J.-N.; Largeau, C.

    A detailed knowledge of the insoluble organic matter (IOM) of the meteorites is essential to estimate to what extent the interstellar organic matter was preserved during the formation of the solar system and to decipher the synthetic pathways of this matter in space. Although predominant, the insoluble organic fraction has been much less extensively studied than soluble one due to specific analytical difficulties. The present work reports the examination of the IOM of two carbonaceous meteorites, Orgueil and Murchison through a number of various spectroscopic and microscopic methods, i. e. XANES for sulphur, carbon and nitrogen, solid state 13C NMR, electron paramagnetic resonance, electron nuclear double resonance and high resolution transmission electron microscopy.

  2. Chemical structure of the Chromophoric Dissolved Organic Matter (CDOM) fluorescent matter.

    Science.gov (United States)

    Blough, N. V.; Del Vecchio, R.; Cartisano, C. M.; Bianca, M.

    2017-12-01

    The structure(s), distribution and dynamics of CDOM have been investigated over the last several decades largely through optical spectroscopy (including both absorption and fluorescence) due to the fairly inexpensive instrumentation and the easy-to-gather data (over thousands published papers from 1990-2016). Yet, the chemical structure(s) of the light absorbing and emitting species or constituents within CDOM has only recently being proposed and tested through chemical manipulation of selected functional groups (such as carbonyl and carboxylic/phenolic containing molecules) naturally occurring within the organic matter pool. Similarly, fitting models (among which the PArallel FACtor analysis, PARAFAC) have been developed to better understand the nature of a subset of DOM, the CDOM fluorescent matter (FDOM). Fluorescence spectroscopy coupled with chemical tests and PARAFAC analyses could potentially provide valuable insights on CDOM sources and chemical nature of the FDOM pool. However, despite that applications (and publications) of PARAFAC model to FDOM have grown exponentially since its first application/publication (2003), a large fraction of such publications has misinterpreted the chemical meaning of the delivered PARAFAC `components' leading to more confusion than clarification on the nature, distribution and dynamics of the FDOM pool. In this context, we employed chemical manipulation of selected functional groups to gain further insights on the chemical structure of the FDOM and we tested to what extent the PARAFAC `components' represent true fluorophores through a controlled chemical approach with the ultimate goal to provide insights on the chemical nature of such `components' (as well as on the chemical nature of the FDOM) along with the advantages and limitations of the PARAFAC application.

  3. The energetic and chemical signatures of persistent soil organic matter

    DEFF Research Database (Denmark)

    Barré, Pierre; Plante, Alain F.; Cecillon, Lauric

    2016-01-01

    A large fraction of soil organic matter (OM) resists decomposition over decades to centuries as indicated by long radiocarbon residence times, but the mechanisms responsible for the long-term (multi-decadal) persistence are debated. The current lack of mechanistic understanding limits our ability...

  4. Chemical examination of the organic matter in oil shales

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, J B

    1914-01-01

    The analyses of Broxburn (Scotland), Pumpherston (Scotland), Armadale (Scotland), Australian, and Knightsbridge oil shales were given. Also, the action of nitric acid and solvents on some of the oil shales was determined. Carbon-hydrogen ratios of the oil shales varied from 6 to more than 8, and the shales with the lowest ratio (most hydrogen per carbon) produced the largest amount of oil from a given amount of organic matter. There was little resinous material in the oil shales, and most of the organic matter was insoluble in organic solvents. Nitric acid oxidized Australian torbanite, Broxburn shale, New Battle cannel coal (Scotland), and Glenfullock peat to organic acids. The hydrogen content of the organic acids obtained by oxidizing the following materials increased from ordinary coal to cannel coal to peat to Broxburn shale to torbanite. The organic substance in oil shale is a decomposition product of vegetable matter similar to that found in peat and cannel coal, and it was produced by a definite combination of external conditions.

  5. CHEMICAL CLEANING OF NANOFILTRATION MEMBRANES FOULED BY ORGANIC MATTERS

    Directory of Open Access Journals (Sweden)

    CHARLENE C. H. KOO

    2016-07-01

    Full Text Available Membrane fouling is a term to describe non-integral substance on membrane surface which results in rapid decline of permeation flux and deteriorate the performance of membrane. Chemical cleaning agents especially like alkaline cleaners are most widely employed to restore the membrane performance. This research mainly investigated the potential use of sodium hydroxide (NaOH and sodium hypochlorite (NaOCl as the chemical cleaning agents to restore the permeate flux of organically fouled nanofiltration (NF membranes under varying applied pressure and flow condition. The performances of the cleaning protocols were quantified using flux recovery and resistance removal. The results demonstrated that NaOCl is more effective than NaOH. This observation is also in line with FTIR analysis in which the transmittance intensity showed by FTIR spectra of NaOCl is higher than that of NaOH. The results also reported that higher flux recovery and resistance removal were achieved when the fouled NF membranes were cleaned with higher concentration of chemical agents and applied pressure. However, the improvements of flux recovery and resistance removal by increasing the applied pressure were found insignificant at higher applied pressure range (16 to 18 bar than the lower applied pressure range (i.e. 12 to 14 bar. This research plays an important role by identifying the key parameters that could restore the flux of organically fouled NF membranes significantly.

  6. Soil organic matter studies

    International Nuclear Information System (INIS)

    1977-01-01

    A total of 77 papers were presented and discussed during this symposium, 37 are included in this Volume II. The topics covered in this volume include: biochemical transformation of organic matter in soils; bitumens in soil organic matter; characterization of humic acids; carbon dating of organic matter in soils; use of modern techniques in soil organic matter research; use of municipal sludge with special reference to heavy metals constituents, soil nitrogen, and physical and chemical properties of soils; relationship of soil organic matter and plant metabolism; interaction between agrochemicals and organic matter; and peat. Separate entries have been prepared for those 20 papers which discuss the use of nuclear techniques in these studies

  7. Chemical-Structural Changes of Organic Matter in a Semi-Arid Soil After Organic Amendment

    Institute of Scientific and Technical Information of China (English)

    C.NICOL(A)S; G.MASCIANDARO; T.HERN(A)NDEZ; C.GARCIA

    2012-01-01

    A 9-month incubation experiment using composted and non-composted amendments derived from vine pruning waste and sewage sludge was carried out to study the effects of the nature and stability of organic amendments on the structural composition of organic matter (OM) in a semi-arid soil. The changes of soil OM,both in the whole soil and in the extractable carbon with pyrophosphate,were evaluated by pyrolysis-gas chromatography and chemical analyses.By the end of the experiment,the soils amended with pruning waste exhibited less organic carbon loss than those receiving sewage sludge.The non-composted residues increased the aliphatic-pyrolytic products of the OM,both in the whole soil and also in the pyrophosphate extract,with the products derived from peptides and proteins being significantly higher.After 9 months,in the soils amended with pruning waste the relative abundance of phenolic-pyrolytic products derived from phenolic compounds,lignin and proteins in the whole soil tended to increase more than those in the soils amended with sewage sludge.However,the extractable OM with pyrophosphate in the soils amended with composted residues tended to have higher contents of these phenolic-pyrolytic products than that in non-composted ones.Thus,despite the stability of pruning waste,the composting of this material promoted the incorporation of phenolic compounds to the soil OM.The pyrolytic indices (furfural/pyrrole and aliphatic/aromatic ratios) showed the diminution of aliphatic compounds and the increase of aromatic compounds,indicating the stabilization of the OM in the amended soils after 9 months.In conclusion,the changes of soil OM depend on the nature and stability of the organic amendments,with composted vine pruning waste favouring humification.

  8. A Chemical Comparison of STARDUST Organics with Insoluble Organic Matter in Chondritic Meteorites

    Science.gov (United States)

    Cody, G. D.; Yabuta, H.; Alexander, C. M.; Araki, T.; Kilcoyne, D.

    2006-12-01

    We have analyzed 15 organic rich particles extracted from the aerogel capture device flown on the STARDUST mission spacecraft to comet Wild 2 using C-, N-, and O-X-ray Absorption Near Edge Structure (XANES) spectroscopy. Data were acquired with the Scanning Transmission X-ray Microscopy (STXM) beam line 5.3.2 at the Advanced Light Source, Lawrence Berkeley Laboratory. XANES can provide both quantitative molecular functional group information and atomic N/C and O/C data. We use these data to place the organic matter extracted from the Aerogel Capture device in context with a large database of C-, N-, and O-XANES spectra obtained on meteoritic Insoluble Organic Matter (IOM) obtained from type 1, 2, and 3 chondrites. We find that the organic chemistry of the particles extracted from aerogel varies in functional group abundances, but is universally very rich in heteroatoms (N and O). In several cases the organic carbon is closely associated with silica (possibly derived from the aerogel), but at a concentration far in excess of the intrinsic carbon abundance of synthesized (and flown) aerogel. Independently, 29-Si, 13-C, and 1-H solid state NMR was applied to analyze the nature of organic carbon present in the aerogel as byproduct of the synthesis. The intrinsic aerogel carbon is very simple in its functional group chemistry, very low in abundance, and differs completely from that detected in the extracted organic particles.

  9. On the Chemical Characterization of Organic Matter in Rain at Mexico City.

    Science.gov (United States)

    Montero-Martinez, G.; Andraca-Ayala, G. L.; Hernández-Nagay, D. P.; Mendoza-Trejo, A.; Rivera-Arellano, J.; Rosado-Abon, A.; Roy, P. D.

    2016-12-01

    The chemical composition of the aerosol plays a central role in atmospheric processes and has influence on the hydrological cycle. Clouds form through the nucleation of water vapor on certain atmospheric aerosol particles, called cloud condensation nuclei (CCN). Also, precipitating particles scavenge some other aerosol particles on their way to the surface. Atmospheric particles are a mixture of organic and inorganic materials, both soluble and insoluble in water. Aerosol chemical characterization indicates a larger variety of compounds in urban areas respect to other regions. Thus, chemical composition of rainwater may represent an important aspect for estimating atmospheric air pollution. It has been recognized that organic species present in aerosol particles are important in the formation of cloud droplets. Therefore, the information about the organic compounds in precipitation samples may be helpful to understand their effects on the formation of clouds and rain, as well as their sources. Organic acids are ubiquitous components of aerosols and have been identified in precipitation water. In this work, preliminary results of the content of soluble organic (neutral and acidic) matter in rainwater samples collected in Mexico City during 2015 will be presented. The organic compounds content was performed by using an ionic chromatographic methodology with gradient elution; so the total amount was evaluated as the sum of four fractions: neutral/basic, mono-, bi-, and poly-acid compounds. The outcomes suggest that most of the amount of organic substances soluble in water is contained by the neutral/basic and mono-acid fractions. Regarding the total amount of water soluble organic compounds, the rain samples collected in Mexico City are in agreement with some others reported for large urban areas.

  10. The chemical structure of the insoluble organic matter from carbonaceous meteorites

    Science.gov (United States)

    Derenne, S.; Robert, F.

    2008-09-01

    Carbonaceous chondrites are the most primitive objects of the solar system. They contain substantial amounts of carbon (up to 3%), mostly occurring in macromolecular insoluble organic matter (IOM). This IOM is generally considered as a record of interstellar synthesis and may contain precursors of prebiotic molecules possibly deposited on earth by meteoritic bombardments. For these reasons, chondritic IOM has been raising interest for long and it is therefore of special interest to decipher its chemical structure. It is now well established that the chemical structure of this macromolecular material is based on aromatic moieties linked by short aliphatic chains and comprising substantial amounts of heteroatoms. However, its precise chemical structure could only be recently specified. The aim of this presentation is to propose a molecular model for the chemical structure of IOM isolated from non-metamorphosed carbonaceous chondrites. This model is derived from a large set of data obtained through a combination of techniques including various spectrocopies, high resolution transmission electron microscopy (HRTEM) and chemical and thermal degradations. Cosmochemical implications of such a structure will also be discussed.

  11. Chemical attributes, total organic carbon stock and humified fractions of organic matter soil submitted to different systems of sugarcane management

    Directory of Open Access Journals (Sweden)

    Jean Sérgio Rosset

    2014-10-01

    Full Text Available Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV, without application of burnt cane waste (CQS, with burnt cane vinasse application (CQV, with application of burnt cane filter cake (CQTF and burnt cane with joint application of vinasse and filter cake (CQVTF. For reference we used an area of natural vegetation (NV, Cerrado sensu stricto. Treatment CQVTF showed improvement in soil chemical properties, increased inventory levels of total organic carbon – TOC (values ranging from 21.28 to 40.02 Mg ha-1 and humified fractions of soil organic matter in relation to other treatments. The CQS area at a depth of 0-0.05 m, showed the greatest losses of soil TOC stocks (56.3% compared to NV. The adoption of management presented CCV and chemical attributes of the soil TOC stocks equivalent to those observed in areas with CQV CQTF and despite the short period of adoption (3 years. The TOC correlated with the sum of bases (r = 0.76 **, cation exchange capacity (r = 0.59 ** and base saturation (r = 0.63 **, while the humic acids (r = 0.40 ** fulvic acids (r = 0.49 ** and humin (r = 0.59 ** correlated with the cation exchange capacity of the soil. These results indicate that the preservation of trash in the management of cane sugar added to the application of vinasse and filter cake increases the TOC stocks promoting improvement in soil chemical properties.

  12. Chemical composition and cycling of dissolved organic matter in the Mid-Atlantic Bight

    Science.gov (United States)

    Aluwihare, Lihini I.; Repeta, Daniel J.; Chen, Robert F.

    This study focuses on the chemical characterization of high molecular-weight dissolved organic matter (HMW DOM) isolated from the Middle Atlantic Bight in April 1994 and March 1996. Using proton nuclear magnetic resonance spectroscopy ( 1HNMR) and monosaccharide analysis we compared both spatial and temporal variations in the chemical structure of HMW DOM across this region. Our analyses support the presence of at least two compositionally distinct components to HMW DOM. The major component is acyl polysaccharide (APS), a biopolymer rich in carbohydrates, acetate and lipid, accounting for between 50% and 80% of the total high molecular-weight dissolved organic carbon (HMW DOC) in surface samples. APS is most abundant in fully marine, surface-water samples, and is a product of autochthonous production. Organic matter with spectral properties characteristic of humic substances is the second major component of HMW DOM. Humic substances are most abundant (up to 49% of the total carbon) in samples collected from estuaries, near the coast, and in deep water, suggesting both marine and perhaps terrestrial sources. Radiocarbon analyses of neutral monosaccharides released by the hydrolysis of APS have similar and modern (average 71‰) Δ 14C values. Radiocarbon data support our suggestion that these sugars occur as part of a common macromolecule, with an origin via recent biosynthesis. Preliminary radiocarbon data for total neutral monosaccharides isolated from APS at 300 and 750 m show this fraction to be substantially enriched relative to total HMW DOC and DOC. The relatively enriched radiocarbon values of APS at depth suggest APS is rapidly transported into the deep ocean.

  13. Influence of chemical and structural evolution of dissolved organic matter on electron transfer capacity during composting

    International Nuclear Information System (INIS)

    He, Xiao-Song; Xi, Bei-Dou; Cui, Dong-Yu; Liu, Yong; Tan, Wen-Bin; Pan, Hong-Wei; Li, Dan

    2014-01-01

    Highlights: • Electron transfer capability (ETC) of compost-derived DOM was investigated. • Composting treatment increased the ETC of DOM from municipal solid wastes. • The ETC increase related to humic matter, and molecule weight, and N and S content. - Abstract: Dissolved organic matter (DOM) can mediate electron transfer and change chemical speciation of heavy metals. In this study, the electron transfer capability (ETC) of compost-derived DOM was investigated through electrochemical approaches, and the factors influencing the ETC were studied using spectral and elemental analysis. The results showed that the electron accepting capacity (EAC) and electron donating capacity (EDC) of compost-derived DOM were 3.29–40.14 μmol e− (g C) −1 and 57.1– 346.07 μmol e− (g C) −1 , respectively. Composting treatment increased the fulvic- and humic-like substance content, oxygenated aliphatic carbon content, lignin-derived aromatic carbon content, molecule weight, and N and S content of DOM, but decreased the aliphatic carbon content and the C and H content. This conversion increased the EDC and EAC of the DOM during composting

  14. Influence of chemical and structural evolution of dissolved organic matter on electron transfer capacity during composting

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiao-Song [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Innovation base of Ground Water and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing 100012 (China); Xi, Bei-Dou, E-mail: hexs82@126.com [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Innovation base of Ground Water and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing 100012 (China); Cui, Dong-Yu [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Innovation base of Ground Water and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing 100012 (China); Liu, Yong [Guangdong Key Laboratory of Agro-Environmental Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Tan, Wen-Bin; Pan, Hong-Wei; Li, Dan [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Innovation base of Ground Water and Environmental System Engineering, Chinese Research Academy of Environmental Science, Beijing 100012 (China)

    2014-03-01

    Highlights: • Electron transfer capability (ETC) of compost-derived DOM was investigated. • Composting treatment increased the ETC of DOM from municipal solid wastes. • The ETC increase related to humic matter, and molecule weight, and N and S content. - Abstract: Dissolved organic matter (DOM) can mediate electron transfer and change chemical speciation of heavy metals. In this study, the electron transfer capability (ETC) of compost-derived DOM was investigated through electrochemical approaches, and the factors influencing the ETC were studied using spectral and elemental analysis. The results showed that the electron accepting capacity (EAC) and electron donating capacity (EDC) of compost-derived DOM were 3.29–40.14 μmol{sub e−} (g C){sup −1} and 57.1– 346.07 μmol{sub e−} (g C){sup −1}, respectively. Composting treatment increased the fulvic- and humic-like substance content, oxygenated aliphatic carbon content, lignin-derived aromatic carbon content, molecule weight, and N and S content of DOM, but decreased the aliphatic carbon content and the C and H content. This conversion increased the EDC and EAC of the DOM during composting.

  15. Comparison of the chemical composition of dissolved organic matter in three lakes in Minnesota

    Science.gov (United States)

    Cao, Xiaoyan; Aiken, George R.; Butler, Kenna D.; Mao, Jingdong; Schmidt-Rohr, Klaus

    2018-01-01

    New information on the chemical composition of dissolved organic matter (DOM) in three lakes in Minnesota has been gained from spectral editing and two-dimensional nuclear magnetic resonance (NMR) methods, indicating the effects of lake hydrological settings on DOM composition. Williams Lake (WL), Shingobee Lake (SL), and Manganika Lake (ML) had different source inputs, and the lake water residence time (WRT) of WL was markedly longer than that of SL and ML. The hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions combined comprised >50% of total DOM in these lakes, and contained carboxyl-rich alicyclic molecules (CRAM), aromatics, carbohydrates, and N-containing compounds. The previously understudied TPIA fractions contained fewer aromatics, more oxygen-rich CRAM, and more N-containing compounds compared to the corresponding HPOA. CRAM represented the predominant component in DOM from all lakes studied, and more so in WL than in SL and ML. Aromatics including lignin residues and phenols decreased in relative abundances from ML to SL and WL. Carbohydrates and N-containing compounds were minor components in both HPOA and TPIA and did not show large variations among the three lakes. The increased relative abundances of CRAM in DOM from ML, SL to WL suggested the selective preservation of CRAM with increased residence time.

  16. Decomposition of soil organic matter from boreal black spruce forest: Environmental and chemical controls

    Science.gov (United States)

    Wickland, K.P.; Neff, J.C.

    2008-01-01

    Black spruce forests are a dominant covertype in the boreal forest region, and they inhabit landscapes that span a wide range of hydrologic and thermal conditions. These forests often have large stores of soil organic carbon. Recent increases in temperature at northern latitudes may be stimulating decomposition rates of this soil carbon. It is unclear, however, how changes in environmental conditions influence decomposition in these systems, and if substrate controls of decomposition vary with hydrologic and thermal regime. We addressed these issues by investigating the effects of temperature, moisture, and organic matter chemical characteristics on decomposition of fibric soil horizons from three black spruce forest sites. The sites varied in drainage and permafrost, and included a "Well Drained" site where permafrost was absent, and "Moderately well Drained" and "Poorly Drained" sites where permafrost was present at about 0.5 m depth. Samples collected from each site were incubated at five different moisture contents (2, 25, 50, 75, and 100% saturation) and two different temperatures (10??C and 20??C) in a full factorial design for two months. Organic matter chemistry was analyzed using pyrolysis gas chromatography-mass spectrometry prior to incubation, and after incubation on soils held at 20??C, 50% saturation. Mean cumulative mineralization, normalized to initial carbon content, ranged from 0.2% to 4.7%, and was dependent on temperature, moisture, and site. The effect of temperature on mineralization was significantly influenced by moisture content, as mineralization was greatest at 20??C and 50-75% saturation. While the relative effects of temperature and moisture were similar for all soils, mineralization rates were significantly greater for samples from the "Well Drained" site compared to the other sites. Variations in the relative abundances of polysaccharide-derivatives and compounds of undetermined source (such as toluene, phenol, 4-methyl phenol, and

  17. NMR studies of chemical structural variation of insoluble organic matter from different carbonaceous chondrite groups

    Science.gov (United States)

    Cody, George D.; Alexander, Conel M. O.'D.

    2005-02-01

    Solid-state 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopic experiments have been performed on isolated meteoritic Insoluble Organic Matter (IOM) spanning four different carbonaceous chondrite meteorite groups; a CR2 (EET92042), a CI1 (Orgueil), a CM2 (Murchison), and the unique C2 meteorite, Tagish Lake. These solid state NMR experiments reveal considerable variation in bulk organic composition across the different meteorite group's IOM. The fraction of aromatic carbon increases as CR2 meteorite groups. Single pulse (SP) 13C magic angle spinning (MAS) NMR experiments reveal the presence of nanodiamonds with an apparent concentration ranking in the IOM of CR2 IOM of all four meteoritic IOM fractions are highly substituted. Fast spinning SP 1H MAS NMR spectral data combined with other NMR experimental data reveal that the average hydrogen content of sp 3 bonded carbon functional groups is low, requiring a high degree of aliphatic chain branching in each IOM fraction. The variation in chemistry across the meteorite groups is consistent with alteration by low temperature chemical oxidation. It is concluded that such chemistry principally affected the aliphatic moieties whereas the aromatic moieties and nanodiamonds may have been largely unaffected.

  18. Changes in soil chemical properties as affected by pyrogenic organic matter amendment with different intensity and frequency

    NARCIS (Netherlands)

    Wang, Ruzhen; Zhang, Yulan; Cerda Bolinches, Artemio; Cao, Mingming; Zhang, Yongyong; Yin, Jinfei; Jiang, Yong; Chen, Lijun

    2017-01-01

    Pyrogenic organic matter (PyOM) has long been used as a soil amendment to improve soil physicochemical properties. However, few studies simultaneously investigated both intensities and frequencies of PyOM addition on soil chemical properties of soil base cations, soil pH buffering capacity (pHBC),

  19. Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest

    International Nuclear Information System (INIS)

    Koarashi, Jun; Iida, Takao; Asano, Tomohiro

    2005-01-01

    To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon ( 14 C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of 14 C abundances showed that (1) bomb-derived 14 C has penetrated the first 16 cm mineral soil at least; (2) Δ 14 C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived 14 C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived 14 C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales

  20. Contribution to physico-chemical study of Timahdit bituminous schists (Morocco): Organic matters and metalloporphyrins

    International Nuclear Information System (INIS)

    Saoiabi, A.

    1982-01-01

    The Timahdit bituminous schists have been analysed by different methods. The experimental results obtained using these methods concern the behaviour of the schists and the Kerogen facing the pyrolysis, as well as the separation of the hydrocarbons and the metalloporphyrins. For this purpose the techniques used are: 'Rock Eval' pyrolysis, thermogravimetric analysis and electron paramagnetic resonance (E.P.R.) for the raw rock and the Kerogen; infrared (I.R.), gas chromatography and E.P.R. for the extracted organic matters; E.P.R., I.R., nuclear magnetic resonance (N.M.R.), ultraviolet (U.V.) and mass spectrometry for the metalloporphyrins identification and characterization. The analysis of these schists has shown that: We can extract per solvent only 1% of organic matters, ferric oxide hasn't any effect neither on the pyrolysis nor on the organic matters extraction and that the Kerogen of these schists are relatively rich in hydrocarbonic compounds. The gas chromatography reveal the presence of alkanes with odd number of carbons and isoprenoids. All these criteria indicate an immature, little developped organic matter which having probably a marine origin but possessing a good oil potential. It has also been observed that a part of Iron, Nickel and Vanadium in the schists are incorporated into the organic matters. Nickel and Vanadium are into macrocycles which are porphyrins. A method for extracting and separating these porphyrins has been developped. 43 figs., 21 tabs., 58 refs. (author)

  1. Soil Chemical Properties and Nutrient Uptake of Cocoa as Affected by Application of Different Organic Matters and Phosphate Fertilizers

    Directory of Open Access Journals (Sweden)

    Sugiyanto Sugiyanto

    2008-07-01

    Full Text Available Effort repair of land quality better be done by simultan namely with application of organic matters and inorganic fertilization. The objective of this research is to study the effect of varied organic matters source and phosphate fertilizers on the chemicals soil characteristic and cocoa nutrient uptake. The experiment was laid experimentally in split-plot design and environmentally in randomized complete block design. The main plot was source of P consisted of, control, SP 36 and rock phosphate in dosage of 200 mg P2O5 per kg of air dry soil. Source of organic matter as sub-plot consisted of control (no organic matter, cow dung, cocoa pod husk compost and sugar cane filter cake, each in dosage of 2.5 and 5.0%. Result of this experiment showed application of cow dung, cocoa pod husk compost and sugar cane filter cake increased content of C, N, Ca exchangeable, Fe available, and pH in soil, and SP 36 increased availability of P in soil. Application of sugar cane filter cake increased N, K, Ca, Mg, and SO4 uptake but did not increase Cl uptake, application of cow dung in dosage 5% increased N, K, and Cl uptake and cocoa pod husk compost dosage 5% increased N and K uptake of cocoa. SP 36 increased Mg uptake of cocoa but rock phosphate did not increase it. They were not interaction between organic matters and phosphate fertilizers to nutrient uptake of cocoa. Nutrient soil content as affected by organic matters correlated with nutrient uptake of cocoa.Key words : soil chemical properties, nutrient uptake, cocoa, organic matter, phosphate fertlizers.

  2. Chemical and optical changes in freshwater dissolved organic matter exposed to solar radiation

    Science.gov (United States)

    Osburn, C.L.; Morris, D.P.; Thorn, K.A.; Moeller, R.E.

    2001-01-01

    We studied the chemical and optical changes in the dissolved organic matter (DOM) from two freshwater lakes and a Sphagnum bog after exposure to solar radiation. Stable carbon isotopes and solid-state 13C-NMR spectra of DOM were used together with optical and chemical data to interpret results from experimental exposures of DOM to sunlight and from seasonal observations of two lakes in northeastern Pennsylvania. Solar photochemical oxidation of humic-rich bog DOM to smaller LMW compounds and to DIC was inferred from losses of UV absorbance, optical indices of molecular weight and changes in DOM chemistry. Experimentally, we observed a 1.2??? enrichment in ??13C and a 47% loss in aromatic C functionality in bog DOM samples exposed to solar UVR. Similar results were observed in the surface waters of both lakes. In late summer hypolimnetic water in humic Lake Lacawac, we observed 3 to 4.5??? enrichments in ??13C and a 30% increase in aromatic C relative to early spring values during spring mixing. These changes coincided with increases in molecular weight and UV absorbance. Anaerobic conditions of the hypolimnion in Lake Lacawac suggest that microbial metabolism may be turning over allochthonous C introduced during spring mixing, as well as autochthonous C. This metabolic activity produces HMW DOM during the summer, which is photochemically labile and isotopically distinct from allochthonous DOM or autochthonous DOM. These results suggest both photooxidation of allochthonous DOM in the epilimnion and autotrophic production of DOM by bacteria in the hypolimnion cause seasonal trends in the UV absorbance of lakes.

  3. How soil organic matter composition controls hexachlorobenzene-soil-interactions: adsorption isotherms and quantum chemical modeling.

    Science.gov (United States)

    Ahmed, Ashour A; Kühn, Oliver; Aziz, Saadullah G; Hilal, Rifaat H; Leinweber, Peter

    2014-04-01

    Hazardous persistent organic pollutants (POPs) interact in soil with the soil organic matter (SOM) but this interaction is insufficiently understood at the molecular level. We investigated the adsorption of hexachlorobenzene (HCB) on soil samples with systematically modified SOM. These samples included the original soil, the soil modified by adding a hot water extract (HWE) fraction (soil+3 HWE and soil+6 HWE), and the pyrolyzed soil. The SOM contents increased in the order pyrolyzed soilsoilsoil+3 HWEsoil+6 HWE. For the latter three samples this order was also valid for the HCB adsorption. The pyrolyzed soil adsorbed more HCB than the other samples at low initial concentrations, but at higher concentrations the HCB adsorption became weaker than in the samples with HWE addition. This adsorption combined with the differences in the chemical composition between the soil samples suggested that alkylated aromatic, phenol, and lignin monomer compounds contributed most to the HCB adsorption. To obtain a molecular level understanding, a test set has been developed on the basis of elemental analysis which comprises 32 representative soil constituents. The calculated binding energy for HCB with each representative system shows that HCB binds to SOM stronger than to soil minerals. For SOM, HCB binds to alkylated aromatic, phenols, lignin monomers, and hydrophobic aliphatic compounds stronger than to polar aliphatic compounds confirming the above adsorption isotherms. Moreover, quantitative structure-activity relationship (QSAR) of the binding energy with independent physical properties of the test set systems for the first time indicated that the polarizability, the partial charge on the carbon atoms, and the molar volume are the most important properties controlling HCB-SOM interactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Chemical characterization of organic particulate matter from on-road traffic in Sao Paulo, Brazil

    NARCIS (Netherlands)

    Oyama, Beatriz Sayuri; Andrade, Maria de Fatima; Herckes, Pierre; Dusek, Ulrike; Rockmann, Thomas; Holzinger, Rupert

    2016-01-01

    This study reports emission of organic particulate matter by light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) in the city of Sao Paulo, Brazil, where vehicles run on three different fuel types: gasoline with 25% ethanol (called gasohol, E25), hydrated ethanol (E100), and diesel (with 5%

  5. Chemical characterization of organic particulate matter from on-road traffic in Sao Paulo, Brazil

    NARCIS (Netherlands)

    Oyama, Beatriz Sayuri; Andrade, Maria de Fatima; Herckes, Pierre; Dusek, Ulrike; Rockmann, Thomas; Holzinger, Rupert

    2016-01-01

    This study reports emission of organic particulate matter by light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) in the city of São Paulo, Brazil, where vehicles run on three different fuel types: gasoline with 25 % ethanol (called gasohol, E25), hydrated ethanol (E100), and diesel (with 5 %

  6. Interaction of extrinsic chemical factors affecting photodegradation of dissolved organic matter in aquatic ecosystems

    Czech Academy of Sciences Publication Activity Database

    Porcal, Petr; Dillon, P. J.; Molot, L. A.

    2014-01-01

    Roč. 13, č. 5 (2014), s. 799-812 ISSN 1474-905X R&D Projects: GA ČR(CZ) GAP503/12/0781 Institutional support: RVO:60077344 Keywords : photodegradation * dissolved organic matter * calcium * nitrate * iron * pH Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.267, year: 2014

  7. Chemical evaluation of soil organic matter structure in diverse cropping systems

    Science.gov (United States)

    Soil organic matter (SOM) improves soil structure, nutrient and water retention, and biodiversity while reducing susceptibility to soil erosion. SOM also represents an important pool of C that can be increased to help mitigate global climate change. Our understanding of how agricultural management ...

  8. Study of the occurrence of organic matter, metals and chemicals in the SFR

    International Nuclear Information System (INIS)

    Sundqvist, J.O.

    2001-03-01

    Low- and intermediate level operational waste from the Swedish nuclear power plants, and the Studsvik facility, is currently placed in a repository, termed SFR-l (final repository for radioactive operational waste) near the Forsmark power plant. Two important components in the waste, which can affect the function of the repository, are organic materials, e.g. cloth and paper, and metals (scrap). The release of radionuclides from the repository may be affected by chemical reactions that involve both organic materials and metals. After sealing the repository, the conditions can be such that complexing agents (e.g. isosaccarinic acid) may form when organic materials degrade. These agents typically increase the mobility of radionuclides. Formation of gas, mainly due to metal corrosion, may affect the barrier system, surrounding the waste, such that the release of radionuclides is enhanced. SKB makes an annual report with a compilation of the waste that has been placed in SFR-l . The compilation contains both the amount of waste placed in the repository during the last year and a compilation of the waste that have been placed since the stall of SFR. Moreover, SKB provides a prognosis of the future situation in SFR-1 every third year. SKI (the Swedish Nuclear Power Inspectorate), is responsible for reviewing this reporting. This study was initiated with the purpose of evaluating the uncertainties in SKB's estimates of the amounts of organic matter, metals and chemicals in the waste in SFR- I. The estimates of the quantities of e.g. cellulose and metals in the waste are based on a method which is utilising what is called normal-containers. The waste is classified into certain waste categories. For each waste category there is a specified, presumed composition, named normal-container. The results of this study suggest that the documentation provided by SKB is lacking in some respects. There are for instance examples of incomplete notification of waste and container types

  9. Chemical composition of phytoplankton and Particulate Organic Matter in the Ría de Vigo (NW Spain

    Directory of Open Access Journals (Sweden)

    A. F. Ríos

    1998-09-01

    Full Text Available Elemental (C, H, O, N, Si, P and biochemical composition (proteins, carbohydrates, lipids, phosphorus compounds, chlorophyll and opal in particulate organic matter, diatoms, other autotrophs, heterotrophs and detritus from natural plankton were established simultaneously by measuring relatively few components. Using standard techniques in marine chemistry on board ship, it is possible to infer a great deal about the composition and condition of the plankton. In addition, the organic matter content in terms of cell volume was determined for each group of plankton. Variation of chemical composition with depth was also considered. The ratio carbohydrates/lipids (Cbh/Lip was used as an indicator of the chemical quality of the plankton.

  10. Deuterium in organic matter

    International Nuclear Information System (INIS)

    Straaten, C.M. van der.

    1981-01-01

    In order to obtain an insight in the processes governing the macroclimate on earth, a knowledge is required of the behaviour of climates in the past. It is well known that D/H ratio of rain varies with temperature determined by latitude as well as by season. Because land plants use this water during the assimilation process, it is expected that the D/H variations are propagated in the organic plant matter. The D/H palaeoclimatic method has therefore been applied to peat to distinguish between the chemical constituents and trace the stable hydrogen fraction in the organic matter. The relation between the hydrogen isotopic composition of precipitation and climatic factors such as the temperature have also been studied. (Auth.)

  11. Chemical and isotopic composition of marine organic matter as indicators of its origin

    International Nuclear Information System (INIS)

    Malej, A.

    1989-07-01

    The present study was carried out to evaluate the relative importance of marine and terrestrial sources of Particulate Organic Matter (POM) in the Northern Adriatic Sea. Samples of POM were obtained from the water column at 14 stations using Niskin bottles at 4 depths and sediment traps (placed near the sea floor). Additional samples were obtained of likely source organic matter: sewage, river POM, phytoplankton bloom material, zooplankton, jelly-fish and bethic macrophytes. All samples were analyzed for total carbon and nitrogen and the delta C-13/C-12 ratio (by mass spectrometry). Marine and terrestrial sources of POM were clearly distinguished by their isotopic ratios. A linear model was set up to evaluate the relative importance of these sources at each sampling station. Except in the immediate vicinity of river sources, the marine component appears to dominate. 7 refs, 5 figs, 1 tab

  12. Impact of Pinus Afforestation on Soil Chemical Attributes and Organic Matter in South Brazilian highlands

    Science.gov (United States)

    Pinheiro Dick, D.; Benvenuti Leite, S.; Dalmolin, R.; Almeida, H.; Knicker, H.; Martinazzo, R.

    2009-04-01

    The region known as Campos de Cima da Serra, located at 800 to 1400 m above sea level in the northeas of Rio Grande do Sul State, Brazil, is covered by a mosaic of natural grassland and Araucaria forest. Cattle raising, introduced by the first European settlers about 200 years ago, is the traditional economic activity in the region, occurring extensively and continuously on the natural pasture. In the last 30 years, while seeking for higher profits, local farmers have introduced agricultural crops and Pinus Taeda plantations in the original pasture lands. Pinus plantations are established in this area as dense monocultures and not as a sylvipastoral system, representing, thus, a severe threaten to the Campos' biodiversity. The soils are shallow, though very acidic (pH 4.2) and rich in exchangeable Al (28 to 47% of Al saturation), and present high contents of SOM in the surface layer (in general, higher than 4 %), which shows a low decomposition degree, as indicated by its high proportion of C-O alkyl groups (51 to 59 %). Considering that the biome sustainability of this region is being progressively affected by the change of land use and that systematic studies about exotic trees afforestation in that region are very scarce, our main objective was to investigate the impact of the introduction of Pinus on the SOM composition and chemical attributes of highland soils in 8 (Pi8) and 30 (Pi30) years old plantations, using as reference the original condition under native pasture (NP). In each studied Leptosol, soil samples were collected from three layers down to 15 cm ( 0-5 cm, 5-10 cm and 10-15 cm). Contents of exchangeable cations and of micronutrients and soil pH were determined. The SOM composition was investigated by means of elemental analyses, FTIR and fluorescence spectroscopy (three replicates). Prior to the spectroscopic analyses, samples were demineralized with 10% HF solution and organic matter loss was monitored. From the FTIR spectra, an aromaticity index

  13. Physical and chemical evolution of reduced organic matter in the ISM

    Science.gov (United States)

    Jenniskens, Peter; Blake, David F.

    1995-01-01

    Icy mantles on interstellar grains have been a topic of study in airborne astronomy. Recent laboratory analog studies of the yield of organic residue from UV photolyzed ices have shown that this mechanism can be the most significant source of complex reduced organic matter in the interstellar medium. However, the total yield is a function of the occurrence of heating events that evaporate the ice, i.e. T is greater than 130 K, and the mechanism for such events is debated. Recently, we proposed that the recombination of radicals in the ice does not need high temperature excursions and, instead, occurs during a structural transformation of water ice at temperatures in the range 38 - 68 K.

  14. NMR studies on the chemical alteration of soil organic matter precursors during controlled charring

    Science.gov (United States)

    Knicker, Heike

    2010-05-01

    Beside the production of volatiles, vegetation fire transforms various amounts of labile organic components into recalcitrant dark colored and highly aromatic structures. They are incorporated into soils and are assumed to represent an important sink within the global carbon cycle. In order to elucidate the real importance of PyOM as a C-sink, a good understanding of its chemistry is crucial. Although several 'Black Carbon' (BC) models are reported, a commonly accepted view of the chemistry involved in its formation is still missing. Its biogeochemical recalcitrance is commonly associated with a highly condensed aromatic structure. However, recent studies indicated that this view may be oversimplified for PyOM derived from vegetation fire. In order to bring some more light on the structural properties of PyOM produced during vegetation fire, charred plant residues and model chars derived from typical plant macromolecules (casein, cellulose, lignin and condensed tannins) were subjected to controlled charring under oxic conditions (350°C and 450°C) and then characterized by nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. Subsequently, the chemical features of the PyOM were related to its chemical recalcitrance as determined by chemical oxidation with acid potassium dichromate. Charring cellulose (350°C, 8 min) yielded in a low C-recovery (11%). Treating casein in the same way resulted in a survival of 62% of its C and 46% of its N. Comparable high C-recoveries are reported for lignin. After charring Lolium perenne, 34% of its N and C were recovered. NMR-spectroscopic studies revealed that for this sample most of the charred N and C occurred in pyrrole-type structures. Our studies further indicate that the aromatic skeleton of char accumulating after a vegetation fire must contain remains of the lignin backbone and considerable contributions of furans and anhydrosugars from thermally altered cellulose. Enhancing the temperature during the

  15. Alteration of Chemical Composition of Soil-leached Dissolved Organic Matter under Cryogenic Cycles

    Science.gov (United States)

    Zhang, X.; Bianchi, T. S.; Schuur, E.

    2016-02-01

    Arctic permafrost thawing has drawn great attention because of the large amount of organic carbon (OC) storage in Arctic soils that are susceptible to increasing global temperatures. Due to microbial activities, some of the OC pool is converted in part to greenhouse gases, like CH4 and CO2 gas, which can result in a positive feedback on global warming. In Artic soils, a portion of OC can be mobilized by precipitation, drainage, and groundwater circulation which can in some cases be transported to rivers and eventually the coastal margins. To determine some of the mechanisms associated with the mobilization of OC from soils to aquatic ecosystems, we conducted a series of laboratory soil leaching experiments. Surface soil samples collected from Healy, Alaska were eluted with artificial rain at a constant rate. Leachates were collected over time and analyzed for dissolved organic carbon (DOC) concentrations. Concentrations began from 387-705 mg/L and then dropped to asymptote states to 25-219 mg/L. High-resolution spectroscopy was used to characterize colored dissolved organic matter (CDOM) and CDOM fluorescence intensity also dropped with time. Fluorescence maximum intensity (Fmax) for peak C ranged from 0.7-4.2 RU, with Exmax/Emmax = 310/450 nm. Fmax for peak T ranged from 0.5-3.2 RU, with Exmax/Emmax = 275/325 nm. Peak C: peak T values indicated preferential leaching of humic-like components over protein-like components. After reaching asymptotic levels, samples were stored frozen and then thawed to study the cryogenic impact on OC composition. CDOM intensity and DOC concentration increased after the freeze-thaw cycle. It was likely that cryogenic processes promoted the breakdown of OC and the releases of more DOC from soils. PARAFAC of CDOM excitation and emission matrices (EEMs) will be used to analyze CDOM composition of the soil leachates.

  16. Structural, chemical and isotopic examinations of interstellar organic matter extracted from meteorites and interstellar dust particles

    Science.gov (United States)

    Busemann, Henner; Alexander, Conel M. O'D.; Nittler, Larry R.; Stroud, Rhonda M.; Zega, Tom J.; Cody, George D.; Yabuta, Hikaru; Kilcoyne, A. L. David

    2008-10-01

    Meteorites and Interplanetary Dust Particles (IDPs) are supposed to originate from asteroids and comets, sampling the most primitive bodies in the Solar System. They contain abundant carbonaceous material. Some of this, mostly insoluble organic matter (IOM), likely originated in the protosolar molecular cloud, based on spectral properties and H and N isotope characteristics. Together with cometary material returned with the Stardust mission, these samples provide a benchmark for models aiming to understand organic chemistry in the interstellar medium, as well as for mechanisms that secured the survival of these fragile molecules during Solar System formation. The carrier molecules of the isotope anomalies are largely unknown, although amorphous carbonaceous spheres, so-called nanoglobules, have been identified as carriers. We are using Secondary Ion Mass Spectrometry to identify isotopically anomalous material in meteoritic IOM and IDPs at a ~100-200 nm scale. Organics of most likely interstellar origin are then extracted with the Focused-Ion-Beam technique and prepared for synchrotron X-ray and Transmission Electron Microscopy. These experiments yield information on the character of the H- and N-bearing interstellar molecules: While the association of H and N isotope anomalies with nanoglobules could be confirmed, we have also identified amorphous, micron-sized monolithic grains. D-enrichments in meteoritic IOM appear not to be systematically associated with any specific functional groups, whereas 15N-rich material can be related to imine and nitrile functionality. The large 15N- enrichments observed here (δ15N > 1000 ‰) cannot be reconciled with models using interstellar ammonia ice reactions, and hence, provide new constraints for understanding the chemistry in cold interstellar clouds.

  17. Chemical Form Matters: Differential Accumulation of Mercury Following Inorganic and Organic Mercury Exposures in Zebrafish Larvae

    Energy Technology Data Exchange (ETDEWEB)

    Korbas, Malgorzata; MacDonald, Tracy C.; Pickering, Ingrid J.; George, Graham N.; Krone, Patrick H. (Saskatchewan)

    2013-04-08

    Mercury, one of the most toxic elements, exists in various chemical forms each with different toxicities and health implications. Some methylated mercury forms, one of which exists in fish and other seafood products, pose a potential threat, especially during embryonic and early postnatal development. Despite global concerns, little is known about the mechanisms underlying transport and toxicity of different mercury species. To investigate the impact of different mercury chemical forms on vertebrate development, we have successfully combined the zebrafish, a well-established developmental biology model system, with synchrotron-based X-ray fluorescence imaging. Our work revealed substantial differences in tissue-specific accumulation patterns of mercury in zebrafish larvae exposed to four different mercury formulations in water. Methylmercury species not only resulted in overall higher mercury burdens but also targeted different cells and tissues than their inorganic counterparts, thus revealing a significant role of speciation in cellular and molecular targeting and mercury sequestration. For methylmercury species, the highest mercury concentrations were in the eye lens epithelial cells, independent of the formulation ligand (chloride versus L-cysteine). For inorganic mercury species, in absence of L-cysteine, the olfactory epithelium and kidney accumulated the greatest amounts of mercury. However, with L-cysteine present in the treatment solution, mercuric bis-L-cysteineate species dominated the treatment, significantly decreasing uptake. Our results clearly demonstrate that the common differentiation between organic and inorganic mercury is not sufficient to determine the toxicity of various mercury species.

  18. Linking measurements of biodegradability, thermal stability and chemical composition to evaluate the effects of management on soil organic matter

    Science.gov (United States)

    Gregorich, Ed; Gillespie, Adam; Beare, Mike; Curtin, Denis; Sanei, Hamed; Yanni, Sandra

    2015-04-01

    The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, and C sequestration. Hence, there is interest in developing new ways to accurately quantify and characterise the labile and stable forms of soil organic C. Our objectives in this study were to evaluate and describe relationships among the biodegradability, thermal stability and chemistry of SOM in soil under widely contrasting management regimes. Samples from the same soil under permanent pasture, an arable cropping rotation, and chemical fallow were fractionated (sand: 2000-50 μm; silt: 50-5 μm, and clay: managements and that sand-associated organic matter was significantly more susceptible than that in the silt or clay fractions. Analysis by XANES showed accumulation of carboxylates and strong depletion of amides (protein) and aromatics in the fallow whole soil. Moreover, protein depletion was most significant in the sand fraction of the fallow soil. Sand fractions in fallow and cropped soils were, however, enriched in plant-derived phenols, aromatics and carboxylates compared to the sand fraction of pasture soils. In contrast, ketones, which have been identified as products of microbially-processed organic matter, were slightly enriched in the silt fraction of the pasture soil. These data suggest reduced inputs and cropping restrict the decomposition of plant residues and, without supplemental N additions, protein-N in native SOM is significantly mineralized in fallow systems to meet microbial C mineralization demands. Analytical pyrolysis showed distinct differences in the thermal stability of SOM among the size fractions and management treatments; it also showed that the loss of SOM generally involved dehydrogenation. The temperature at which half of the C was pyrolyzed showed strong correlation with mineralizable C and thus provides solid evidence for a link between the biological and

  19. Soil organic matter

    International Nuclear Information System (INIS)

    1976-01-01

    The nature, content and behaviour of the organic matter, or humus, in soil are factors of fundamental importance for soil productivity and the development of optimum conditions for growth of crops under diverse temperate, tropical and arid climatic conditions. In the recent symposium on soil organic matter studies - as in the two preceding ones in 1963 and 1969 - due consideration was given to studies involving the use of radioactive and stable isotopes. However, the latest symposium was a departure from previous efforts in that non-isotopic approaches to research on soil organic matter were included. A number of papers dealt with the behaviour and functions of organic matter and suggested improved management practices, the use of which would contribute to increasing agricultural production. Other papers discussed the turnover of plant residues, the release of plant nutrients through the biodegradation of organic compounds, the nitrogen economy and the dynamics of transformation of organic forms of nitrogen. In addition, consideration was given to studies on the biochemical transformation of organic matter, characterization of humic acids, carbon-14 dating and the development of modern techniques and their impact on soil organic matter research

  20. Changes in the chemical characteristics of water-extracted organic matter from vermicomposting of sewage sludge and cow dung.

    Science.gov (United States)

    Xing, Meiyan; Li, Xiaowei; Yang, Jian; Huang, Zhidong; Lu, Yongsen

    2012-02-29

    The chemical changes of water-extractable organic matter (WEOM) from five different substrates of sewage sludge enriched with different proportions of cow dung after vermicomposting with Eisenia fetida were investigated using various analytical approaches. Results showed that dissolved organic carbon, chemical oxygen demand, and C/N ratio of the substrates decreased significantly after vermicomposting process. The aromaticity of WEOM from the substrates enhanced considerably, and the amount of volatile fatty acids declined markedly, especially for the cow dung substrate. Gel filtration chromatography analysis showed that the molecular weight fraction between 10(3) and 10(6) Da became the main part of WEOM in the final product. 1H nuclear magnetic resonance spectra revealed that the proportion of H moieties in the area of 0.00-3.00 ppm decreased, while increasing at 3.00-4.25 ppm after vermicomposting. Fluorescence spectra indicated that vermicomposting caused the degradation of protein-like groups, and the formation of fulvic and humic acid-like compounds in the WEOM of the substrates. Overall results indicate clearly that vermicomposting promoted the degradation and transformation of liable WEOM into biological stable substances in sewage sludge and cow dung alone, as well as in mixtures of both materials, and testing the WEOM might be an effective way to evaluate the biological maturity and chemical stability of vermicompost. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. The role of organic matter in the removal of emerging trace organic chemicals during managed aquifer recharge.

    Science.gov (United States)

    Rauch-Williams, T; Hoppe-Jones, C; Drewes, J E

    2010-01-01

    This study explored the effect of different bulk organic carbon matrices on the fate of trace organic chemicals (TOrC) during managed aquifer recharge (MAR). Infiltration through porous media was simulated in biologically active column experiments under aerobic and anoxic recharge conditions. Wastewater effluent derived organic carbon types, differing in hydrophobicity and biodegradability (i. e., hydrophobic acids, hydrophilic carbon, organic colloids), were used as feed substrates in the column experiments. These carbon substrates while fed at the same concentration differed in their ability to support soil biomass growth during porous media infiltration. Removal of degradable TOrC (with the exception of diclofenac and propyphenazone) was equal or better under aerobic versus anoxic porous media infiltration conditions. During the initial phase of infiltration, the presence of biodegradable organic carbon (BDOC) enhanced the decay of degradable TOrC by promoting soil biomass growth, suggesting that BDOC served as a co-substrate in a co-metabolic transformation of these contaminants. However, unexpected high removal efficiencies were observed for all degradable TOrC in the presence of low BDOC concentrations under well adopted oligotrophic conditions. It is hypothesized that removal under these conditions is caused by a specialized microbial community growing on refractory carbon substrates such as hydrophobic acids. Findings of this study reveal that the concentration and character of bulk organic carbon present in effluents affect the degradation efficiency for TOrC during recharge operation. Specifically aerobic, oligotrophic microbiological soil environments present favorable conditions for the transformation of TOrC, including rather recalcitrant compounds such as chlorinated flame retardants. (c) 2009 Elsevier Ltd. All rights reserved.

  2. Stabilization of enzymatically polymerized phenolic chemicals in a model soil organic matter-free geomaterial.

    Science.gov (United States)

    Palomo, Mónica; Bhandari, Alok

    2012-01-01

    A variety of remediation methods, including contaminant transformation by peroxidase-mediated oxidative polymerization, have been proposed to manage soils and groundwater contaminated with chlorinated phenols. Phenol stabilization has been successfully observed during cross polymerization between phenolic polymers and soil organic matter (SOM) for soils with SOM >3%. This study evaluates peroxidase-mediated transformation and removal of 2,4-dichlorophenol (DCP) from an aqueous phase in contact with a natural geomaterial modified to contain negligible (soils with higher SOM. The SOM-free sorbent was generated by removing SOM using a NaOCl oxidation. When horseradish peroxidase (HRP) was used to induce polymerization of DCP, the soil-water phase distribution relationship (PDR) of DCP polymerization products (DPP) was complete within 1 d and PDRs did not significantly change over the 28 d of study. The conversion of DCP to DPP was close to 95% efficient. Extractable solute consisted entirely of DPP with 5% or less of unreacted DCP. The aqueous extractability of DPP from SOM-free geomaterial decreased at longer contact times and at smaller residual aqueous concentrations of DPP. DCP stabilization appeared to have resulted from a combination of sorption, precipitation, and ligand exchange between oligomeric products and the exposed mineral surfaces. Modification of the mineral surface through coverage with DPP enhanced the time-dependent retention of the oligomers. DPP stabilization in SOM-free geomaterial was comparable with that reported in the literature with soil containing SOM contents >1%. Results from this study suggest that the effectiveness of HRP-mediated stabilization of phenolic compounds not only depends on the cross-coupling with SOM, but also on the modification of the surface of the sorbent that can augment affinity with oligomers and enhance stabilization. Coverage of the mineral surface by phenolic oligomers may be analogous to SOM that can potentially

  3. Chemical compositions and sources of organic matter in fine particles of soils and sands from the vicinity of Kuwait city.

    Science.gov (United States)

    Rushdi, Ahmed I; Al-Zarban, Sheikha; Simoneit, Bernd R T

    2006-09-01

    Fine particles in the atmosphere from soil and sand resuspension contain a variety of organic compounds from natural biogenic and anthropogenic matter. Soil and sand samples from various sites near Kuwait city were collected, sieved to retain the fine particles, and extracted with a mixture of dichloromethane and methanol. The extracts were derivatized and analyzed by gas chromatography-mass spectrometry in order to characterize the chemical compositions and sources of the organic components. The major inputs of organic compounds were from both natural biogenic and anthropogenic sources in these samples. Vegetation was the major natural source of organic compounds and included n-alkanols, n-alkanoic acids, n-alkanes, sterols and triterpenoids. Saccharides had high concentrations (31-43%) in the sand dune and seafront samples, indicating sources from decomposed vegation materials and/or the presence of viable microbiota such as bacteria and fungi. Vehicular emission products, leakage of lubricating oils, discarded plastics and emissions from cooking operations were the major anthropogenic inputs in the samples from the urban areas. This input was mainly UCM, n-alkanes, hopanes, plasticizers and cholesterol, respectively.

  4. The effects of dissolved natural organic matter on the adsorption of synthetic organic chemicals by activated carbons and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Karanfil, Tanju

    2011-01-01

    Understanding the influence of natural organic matter (NOM) on synthetic organic contaminant (SOC) adsorption by carbon nanotubes (CNTs) is important for assessing the environmental implications of accidental CNT release and spill to natural waters, and their potential use as adsorbents in engineered systems. In this study, adsorption of two SOCs by three single-walled carbon nanotubes (SWNTs), one multi-walled carbon nanotube (MWNT), a microporous activated carbon fiber (ACF) [i.e., ACF10] and a bimodal porous granular activated carbon (GAC) [i.e., HD4000] was compared in the presence and absence of NOM. The NOM effect was found to depend strongly on the pore size distribution of carbons. Minimal NOM effect occurred on the macroporous MWNT, whereas severe NOM effects were observed on the microporous HD4000 and ACF10. Although the single-solute adsorption capacities of the SWNTs were much lower than those of HD4000, in the presence of NOM the SWNTs exhibited adsorption capacities similar to those of HD4000. Therefore, if released into natural waters, SWNTs can behave like an activated carbon, and will be able to adsorb, carry, and transfer SOCs to other systems. However, from an engineering application perspective, CNTs did not exhibit a major advantage, in terms of adsorption capacities, over the GAC and ACF. The NOM effect was also found to depend on molecular properties of SOCs. NOM competition was more severe on the adsorption of 2-phenylphenol, a nonplanar and hydrophilic SOC, than phenanthrene, a planar and hydrophobic SOC, tested in this study. In terms of surface chemistry, both adsorption affinity to SOCs and NOM effect on SOC adsorption were enhanced with increasing hydrophobicity of the SWNTs. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    Science.gov (United States)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rs) was evaluated in microcosms containing -1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rs values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.

  6. A thermal and chemical degradation approach to decipher pristane and phytane precursors in sedimentary organic matter

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Koopmans, M.P.; Rijpstra, W.I.C.; Klapwijk, M.M.; Lewan, M.D.

    1999-01-01

    A thermal and chemical degradation approach was followed to determine the precursors of pristane (Pr) and phytane (Ph) in samples from the Gessoso-solfifera, Ghareb and Green River Formations. Hydrous pyrolysis of these samples yields large amounts of Pr and Ph carbon skeletons, indicating that

  7. Changes in the chemical characteristics of water-extracted organic matter from vermicomposting of sewage sludge and cow dung

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Meiyan, E-mail: xingmeiyan@tongji.edu.cn [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Li, Xiaowei; Yang, Jian; Huang, Zhidong; Lu, Yongsen [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2012-02-29

    Highlights: Black-Right-Pointing-Pointer Vermicomposting causes an increase in the aromaticity of WEOM from the substrates. Black-Right-Pointing-Pointer Vermicomposting homogenizes the molecular weight of WEOM from the substrates. Black-Right-Pointing-Pointer The WEOM from the vermicompost is characterized by high O-containing groups. Black-Right-Pointing-Pointer The WEOM from the vermicompost includes small aliphatic and protein-like groups. Black-Right-Pointing-Pointer The WEOM test is a good way to evaluate the biological maturity of vermicompost. - Abstract: The chemical changes of water-extractable organic matter (WEOM) from five different substrates of sewage sludge enriched with different proportions of cow dung after vermicomposting with Eisenia fetida were investigated using various analytical approaches. Results showed that dissolved organic carbon, chemical oxygen demand, and C/N ratio of the substrates decreased significantly after vermicomposting process. The aromaticity of WEOM from the substrates enhanced considerably, and the amount of volatile fatty acids declined markedly, especially for the cow dung substrate. Gel filtration chromatography analysis showed that the molecular weight fraction between 10{sup 3} and 10{sup 6} Da became the main part of WEOM in the final product. {sup 1}H nuclear magnetic resonance spectra revealed that the proportion of H moieties in the area of 0.00-3.00 ppm decreased, while increasing at 3.00-4.25 ppm after vermicomposting. Fluorescence spectra indicated that vermicomposting caused the degradation of protein-like groups, and the formation of fulvic and humic acid-like compounds in the WEOM of the substrates. Overall results indicate clearly that vermicomposting promoted the degradation and transformation of liable WEOM into biological stable substances in sewage sludge and cow dung alone, as well as in mixtures of both materials, and testing the WEOM might be an effective way to evaluate the biological maturity and

  8. Changes in the chemical characteristics of water-extracted organic matter from vermicomposting of sewage sludge and cow dung

    International Nuclear Information System (INIS)

    Xing, Meiyan; Li, Xiaowei; Yang, Jian; Huang, Zhidong; Lu, Yongsen

    2012-01-01

    Highlights: ► Vermicomposting causes an increase in the aromaticity of WEOM from the substrates. ► Vermicomposting homogenizes the molecular weight of WEOM from the substrates. ► The WEOM from the vermicompost is characterized by high O-containing groups. ► The WEOM from the vermicompost includes small aliphatic and protein-like groups. ► The WEOM test is a good way to evaluate the biological maturity of vermicompost. - Abstract: The chemical changes of water-extractable organic matter (WEOM) from five different substrates of sewage sludge enriched with different proportions of cow dung after vermicomposting with Eisenia fetida were investigated using various analytical approaches. Results showed that dissolved organic carbon, chemical oxygen demand, and C/N ratio of the substrates decreased significantly after vermicomposting process. The aromaticity of WEOM from the substrates enhanced considerably, and the amount of volatile fatty acids declined markedly, especially for the cow dung substrate. Gel filtration chromatography analysis showed that the molecular weight fraction between 10 3 and 10 6 Da became the main part of WEOM in the final product. 1 H nuclear magnetic resonance spectra revealed that the proportion of H moieties in the area of 0.00–3.00 ppm decreased, while increasing at 3.00–4.25 ppm after vermicomposting. Fluorescence spectra indicated that vermicomposting caused the degradation of protein-like groups, and the formation of fulvic and humic acid-like compounds in the WEOM of the substrates. Overall results indicate clearly that vermicomposting promoted the degradation and transformation of liable WEOM into biological stable substances in sewage sludge and cow dung alone, as well as in mixtures of both materials, and testing the WEOM might be an effective way to evaluate the biological maturity and chemical stability of vermicompost.

  9. Combined organic matter and nitrogen removal from a chemical industry wastewater in a two-stage MBBR system.

    Science.gov (United States)

    Cao, S M S; Fontoura, G A T; Dezotti, M; Bassin, J P

    2016-01-01

    Pesticide-producing factories generate highly polluting wastewaters containing toxic and hazardous compounds which should be reduced to acceptable levels before discharge. In this study, a chemical industry wastewater was treated in a pre-denitrification moving-bed biofilm reactor system subjected to an increasing internal mixed liquor recycle ratio from 2 to 4. Although the influent wastewater characteristics substantially varied over time, the removal of chemical oxygen demand (COD) and dissolved organic carbon was quite stable and mostly higher than 90%. The highest fraction of the incoming organic matter was removed anoxically, favouring a low COD/N environment in the subsequent aerobic nitrifying tank and thus ensuring stable ammonium removal (90-95%). However, during pH and salt shock periods, nitrifiers were severely inhibited but gradually restored their full nitrifying capability as non-stressing conditions were reestablished. Besides promoting an increase in the maximum nitrification potential of the aerobic attached biomass from 0.34 to 0.63 mg [Formula: see text], the increase in the internal recycle ratio was accompanied by an increase in nitrogen removal (60-78%) and maximum specific denitrification rate (2.7-3.3 mg NOx(-)--N). Total polysaccharides (PS) and protein (PT) concentrations of attached biomass were observed to be directly influenced by the influent organic loading rate, while the PS/PT ratio mainly ranged from 0.3 to 0.5. Results of Microtox tests showed that no toxicity was found in the effluent of both the anoxic and aerobic reactors, indicating that the biological process was effective in removing residual substances which might adversely affect the receiving waters' ecosystem.

  10. Chemical cleaning-associated generation of dissolved organic matter and halogenated byproducts in ceramic MBR: Ozone versus hypochlorite.

    Science.gov (United States)

    Sun, Huifang; Liu, Hang; Han, Jiarui; Zhang, Xiangru; Cheng, Fangqin; Liu, Yu

    2018-04-24

    This study characterized the dissolved organic matter (DOM) and byproducts generated after the exposure of activated sludge to ozone and NaClO in ceramic MBR. It was found that NaClO triggered more significant release of DOM than ozone. Proteins with the molecular weight greater than 20 kDa and humic acid like-substances were the principal components of DOM generated by NaClO, while ozone was found to effectively degrade larger biopolymers to low molecular weight substances. The results showed that more than 80% of DOM generated by NaClO and ozone could pass through the 0.2-μm ceramic membrane. Furthermore, total organic chlorine (TOCl) was determined to be the principal species of halogenated byproducts in both cases, while the generation of TOCl by NaClO was much more significant than that by ozone. Only a small fraction of TOCl was removed by the 0.2-μm ceramic membrane. More importantly, the toxic bioassays further revealed that the supernatant of sludge suspension and permeate in the MBR with NaClO cleaning exhibited higher developmental toxicity to the polychaete embryos than those by ozone. The results clearly showed that on-line chemical cleaning with ozone should be a more eco-friendly and safer approach for sustaining long-term membrane permeability in ceramic MBR. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Is old organic matter simple organic matter?

    Science.gov (United States)

    Nunan, Naoise; Lerch, Thomas; Pouteau, Valérie; Mora, Philippe; Changey, Fréderique; Kätterer, Thomas; Herrmann, Anke

    2016-04-01

    Bare fallow soils that have been deprived of fresh carbon inputs for prolonged periods contain mostly old, stable organic carbon. In order to shed light on the nature of this carbon, the functional diversity profiles (MicroResp™, Biolog™ and enzyme activity spectra) of the microbial communities of long-term barefallow soils were analysed and compared with those of the microbial communities from their cultivated counterparts. The study was based on the idea that microbial communities adapt to their environment and that therefore the catabolic and enzymatic profiles would reflect the type of substrates available to the microbial communities. The catabolic profiles suggested that the microbial communities in the long-term bare-fallow soil were exposed to a less diverse range of substrates and that these substrates tended to be of simpler molecular forms. Both the catabolic and enzyme activity profiles suggested that the microbial communities from the long-term bare-fallow soils were less adapted to using polymers. These results do not fit with the traditional view of old, stable carbon being composed of complex, recalcitrant polymers. An energetics analysis of the substrate use of the microbial communities for the different soils suggested that the microbial communities from the long-term bare-fallow soils were better adapted to using readily oxidizable,although energetically less rewarding, substrates. Microbial communities appear to adapt to the deprivation of fresh organic matter by using substrates that require little investment.

  12. Chemical characterization of organic particulate matter from on-road traffic in São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    B. S. Oyama

    2016-11-01

    Full Text Available This study reports emission of organic particulate matter by light-duty vehicles (LDVs and heavy-duty vehicles (HDVs in the city of São Paulo, Brazil, where vehicles run on three different fuel types: gasoline with 25 % ethanol (called gasohol, E25, hydrated ethanol (E100, and diesel (with 5 % biodiesel. The experiments were performed at two tunnels: Jânio Quadros (TJQ, where 99 % of the vehicles are LDVs, and RodoAnel Mário Covas (TRA, where up to 30 % of the fleet are HDVs. Fine particulate matter (PM2.5 samples were collected on quartz filters in May and July 2011 at TJQ and TRA, respectively. The samples were analyzed by thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS and by thermal–optical transmittance (TOT. Emission factors (EFs for organic aerosol (OA and organic carbon (OC were calculated for the HDV and the LDV fleet. We found that HDVs emitted more PM2.5 than LDVs, with OC EFs of 108 and 523 mg kg−1 burned fuel for LDVs and HDVs, respectively. More than 700 ions were identified by TD-PTR-MS and the EF profiles obtained from HDVs and LDVs exhibited distinct features. Unique organic tracers for gasoline, biodiesel, and tire wear have been tentatively identified. nitrogen-containing compounds contributed around 20 % to the EF values for both types of vehicles, possibly associated with incomplete fuel burning or fast secondary production. Additionally, 70 and 65 % of the emitted mass (i.e. the OA originates from oxygenated compounds from LDVs and HDVs, respectively. This may be a consequence of the high oxygen content of the fuel. On the other hand, additional oxygenation may occur during fuel combustion. The high fractions of nitrogen- and oxygen-containing compounds show that chemical processing close to the engine / tailpipe region is an important factor influencing primary OA emission. The thermal-desorption analysis showed that HDVs emitted compounds with higher volatility, and with

  13. Old and stable soil organic matter is not necessarily chemically recalcitrant: Implications for modeling concepts and temperature sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleber, M.; Nico, P.S.; Plante, A.; Filley, T.; Kramer, M.; Swanston, C.; Sollins, P.

    2010-03-01

    Soil carbon turnover models generally divide soil carbon into pools with varying intrinsic decomposition rates. Although these decomposition rates are modified by factors such as temperature, texture, and moisture, they are rationalized by assuming chemical structure is a primary controller of decomposition. In the current work, we use near edge X-ray absorption fine structure (NEXAFS) spectroscopy in combination with differential scanning calorimetry (DSC) and alkaline cupric oxide (CuO) oxidation to explore this assumption. Specifically, we examined material from the 2.3-2.6 kg L{sup -1} density fraction of three soils of different type (Oxisol, Alfisol, Inceptisol). The density fraction with the youngest {sup 14}C age (Oxisol, 107 years) showed the highest relative abundance of aromatic groups and the lowest O-alkyl C/aromatic C ratio as determined by NEXAFS. Conversely, the fraction with the oldest C (Inceptisol, 680 years) had the lowest relative abundance of aromatic groups and highest O-alkyl C/aromatic C ratio. This sample also had the highest proportion of thermally labile materials as measured by DSC, and the highest ratio of substituted fatty acids to lignin phenols as indicated by CuO oxidation. Therefore, the organic matter of the Inceptisol sample, with a {sup 14}C age associated with 'passive' pools of carbon (680 years), had the largest proportion of easily metabolizable organic molecules with low thermodynamic stability, whereas the organic matter of the much younger Oxisol sample (107 years) had the highest proportion of supposedly stable organic structures considered more difficult to metabolize. Our results demonstrate that C age is not necessarily related to molecular structure or thermodynamic stability, and we suggest that soil carbon models would benefit from viewing turnover rate as codetermined by the interaction between substrates, microbial actors, and abiotic driving variables. Furthermore, assuming that old carbon is composed

  14. Natural sulfurization of carbohydrates in marine sediments : consequences for the chemical and carbon isotopic composition of sedimentary organic matter

    NARCIS (Netherlands)

    Dongen, B.E. van

    2003-01-01

    Carbohydrates make up the largest part of the organic matter in the biosphere and are used by living organism for many different reasons. They serve, among others, as carbon and energy source as well as metabolic intermediates. Carbohydrates are generally thought to be remineralized during early

  15. Trials and Tribulations of Fluorescent Dissolved Organic Matter Chemical Interpretations: A case study of polar ice cores

    Science.gov (United States)

    D'Andrilli, J.

    2017-12-01

    Excitation emission matrix fluorescence spectroscopy is widely applied for rapid dissolved organic matter (DOM) characterization in aquatic systems. Fluorescent DOM surveys are booming, not only as a central focus in aquatic environments, but also as an important addition to interdisciplinary research (e.g., DOM analysis in concert with ice core paleoclimate reconstructions, stream metabolism, hydrologic regimes, agricultural developments, and biological activity), opening new doors, not just for novelty, but also for more challenges with chemical interpretations. Recently, the commonly used protein- versus humic-like classifications of DOM have been ineffective at describing DOM chemistry in various systems (e.g., ice cores, wastewaters, incubations/engineered). Moreover, the oversimplification of such classifications used to describe fluorescing components, without further scrutiny, has become commonplace, ultimately producing vague reporting. For example, West Antarctic ice core DOM was shown to contain fluorescence in the low excitation/emission wavelength region, however resolved fluorophores depicting tyrosine- and tryptophan-like DOM were not observed. At first, as literature suggested, we reported this result as protein-like, and concluded that microbial contributions were dominant in deep ice. That initial interpretation would disintegrate the conservation paradigm of atmospheric composition during deposition, the crux of ice core research, and contradict other lines of evidence. This begged the question, "How can we describe DOM chemistry without distinct fluorophores?" Antarctic ice core DOM was dominated by neither tyrosine- nor tryptophan-like fluorescence, causing "unusual" looking fluorescent components. After further examination, deep ice DOM was reported to contain fluorescent species most similar to monolignols and tannin-like phenols, describing the precursors of lignin from low carbon producing environments, consistent with marine sediment

  16. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    International Nuclear Information System (INIS)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (R s ) was evaluated in microcosms containing −1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing R s values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p < 0.001). The calibration data generated can be used to derive pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM. - Highlights: ► We assessed the effect of TOC and stirring on pesticide sampling rates by POCIS. ► Total organic carbon (TOC) had no effect on the sampling rates. ► Water flow and stirring significantly increased the magnitude of the sampling rates. ► The sampling rates generated are directly applicable to field conditions. - This study provides POCIS sampling rates data that can be used to estimate freely dissolved concentrations of toxic pesticides in natural waters.

  17. Quantities and qualities of physical and chemical fractions of soil organic matter under a rye cover crop

    Science.gov (United States)

    To detect the effects of a rye cover crop on labile soil carbon, the light fraction, large particulate organic matter (POM), small POM, and two NaOH-extractable humic fractions were extracted from three depths of a corn soil in central Iowa having an overwinter rye cover crop treatment and a contro...

  18. Solid-state 13C NMR experiments reveal effects of aggregate size on the chemical composition of particulate organic matter in grazed steppe soils

    Science.gov (United States)

    Steffens, M.; Kölbl, A.; Kögel-Knabner, I.

    2009-04-01

    Grazing is one of the most important factors that may reduce soil organic matter (SOM) stocks and subsequently deteriorate aggregate stability in grassland topsoils. Land use management and grazing reduction are assumed to increase the input of OM, improve the soil aggregation and change species composition of vegetation (changes depth of OM input). Many studies have evaluated the impact of grazing cessation on SOM quantity. But until today little is known about the impact of grazing cessation on the chemical quality of SOM in density fractions, aggregate size classes and different horizons. The central aim of this study was to analyse the quality of SOM fractions in differently sized aggregates and horizons as affected by increased inputs of organic matter due to grazing exclusion. We applied a combined aggregate size, density and particle size fractionation procedure to sandy steppe topsoils with different organic matter inputs due to different grazing intensities (continuously grazed = Cg, winter grazing = Wg, ungrazed since 1999 = Ug99, ungrazed since 1979 = Ug79). Three different particulate organic matter (POM; free POM, in aggregate occluded POM and small in aggregate occluded POM) and seven mineral-associated organic matter fractions were separated for each of three aggregate size classes (coarse = 2000-6300 m, medium = 630-2000 m and fine =

  19. Chemical characterization of soil organic matter in a Chesapeake Bay salt marsh: analyzing microbial and vegetation inputs to SOM

    Science.gov (United States)

    Bye, E.; Schreiner, K. M.; Abdulla, H. A.; Minor, E. C.; Guntenspergen, G. R.

    2017-12-01

    Coastal wetlands play a critical role in the global carbon cycle. These ecosystems sequester and store carbon, known as "blue carbon," at a rate two or three orders of magnitude larger than other terrestrial ecosystems, such as temperate, tropical, and boreal forests. Anthropogenic changes to the climate are threatening blue carbon stores in coastal wetland ecosystems. To understand and predict how these important carbon stores will be affected by anthropogenic climate changes, it is necessary to understand the formation and preservation of soil organic matter (SOM) in these ecosystems. This study will present organic geochemical data from two sediment cores collected from the Smithsonian Environmental Research Center site on a salt marsh in Maryland along the Chesapeake Bay. One core is from a location that recently transitioned from a C4 to C3 plant regime, currently dominated by the sedge Shoenplectis americanus. The second core is from a C4 plant (Spartina patens) dominated location in the marsh. The organic geochemistry of these 100 cm deep sediment cores was studied through multiple bulk analyses including stable isotopes, elemental ratios, Fourier-transform infrared spectroscopy (FTIR), solid-state magic-angle-spinning Nuclear Magnetic Resonance (NMR), and compound specific lignin-phenol analysis. By using comprehensive chemical characterization techniques, this study aims to discern between vegetation- and microbially-derived inputs to SOM in blue carbon ecosystems. The results show a general increase in the aromatic content with a concomitant decrease of carbohydrates with depth in both cores. However, substantial differences between the two cores, indicates differing inputs and/or stabilization mechanisms within SOM formed from different vegetation regimes. Further compound specific work will help to elucidate the specific source of compounds within each compound class, in surface and deep SOM, and additionally can help provide evidence for different

  20. Chemical and isotopic signature of bulk organic matter and hydrocarbon biomarkers within mid-slope accretionary sediments of the northern Cascadia margin gas hydrate system

    Science.gov (United States)

    Kaneko, Masanori; Shingai, Hiroshi; Pohlman, John W.; Naraoka, Hiroshi

    2010-01-01

    The chemical and isotopic compositions of sedimentary organic matter (SOM) from two mid-slope sites of the northern Cascadia margin were investigated during Integrated Ocean Drilling Program (IODP) Expedition 311 to elucidate the organic matter origins and identify potential microbial contributions to SOM. Gas hydrate is present at both locations (IODP Sites U1327 and U1328), with distinct patterns of near-seafloor structural accumulations at the cold seep Site U1328 and deeper stratigraphic accumulations at the slope-basin Site U1327. Source characterization and evidence that some components of the organic matter have been diagenetically altered are determined from the concentrations and isotopic compositions of hydrocarbon biomarkers, total organic carbon (TOC), total nitrogen (TN) and total sulfur (TS). The carbon isotopic compositions of TOC (δ13CTOC = −26 to −22‰) and long-chain n-alkanes (C27, C29 and C31, δ13C = −34 to − 29‰) suggest the organic matter at both sites is a mixture of 1) terrestrial plants that employ the C3 photosynthetic pathway and 2) marine algae. In contrast, the δ15NTN values of the bulk sediment (+ 4 to + 8‰) are consistent with a predominantly marine source, but these values most likely have been modified during microbial organic matter degradation. The δ13C values of archaeal biomarker pentamethylicosane (PMI) (− 46.4‰) and bacterial-sourced hopenes, diploptene and hop-21-ene (− 40.9 to − 34.7‰) indicate a partial contribution from methane carbon or a chemoautotrophic pathway. Our multi-isotope and biomarker-based conclusions are consistent with previous studies, based only on the elemental composition of bulk sediments, that suggested a mixed marine-terrestrial organic matter origin for these mid-slope sites of the northern Cascadia margin.

  1. A ω-mercaptoundecylphosphonic acid chemically modified gold electrode for uranium determination in waters in presence of organic matter.

    Science.gov (United States)

    Merli, Daniele; Protti, Stefano; Labò, Matteo; Pesavento, Maria; Profumo, Antonella

    2016-05-01

    A chemically modified electrode (CME) on a gold surface assembled with a ω-phosphonic acid terminated thiol was investigated for its capability to complex uranyl ions. The electrode, characterized by electrochemical techniques, demonstrated to be effective for the determination of uranyl at sub-μgL(-1) level by differential pulse adsorptive stripping voltammetry (DPAdSV) in environmental waters, also in presence of humic matter and other potential chelating agents. The accuracy of the measurements was investigated employing as model probes ligands of different complexing capability (humic acids and EDTA). Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Comparing molecular composition of dissolved organic matter in soil and stream water: Influence of land use and chemical characteristics.

    Science.gov (United States)

    Seifert, Anne-Gret; Roth, Vanessa-Nina; Dittmar, Thorsten; Gleixner, Gerd; Breuer, Lutz; Houska, Tobias; Marxsen, Jürgen

    2016-11-15

    Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS) was used to examine the molecular composition of dissolved organic matter (DOM) from soils under different land use regimes and how the DOM composition in the catchment is reflected in adjacent streams. The study was carried out in a small area of the Schwingbach catchment, an anthropogenic-influenced landscape in central Germany. We investigated 30 different soil water samples from 4 sites and different depths (managed meadow (0-5cm, 40-50cm), deciduous forest (0-5cm), mixed-coniferous forest (0-5cm) and agricultural land (0-5cm, 40-50cm)) and 8 stream samples. 6194 molecular formulae and their magnitude-weighted parameters ((O/C)w, (H/C)w, (N/C)w, (AI-mod)w, (DBE/C)w, (DBE/O)w, (DBE-O)w, (C#)w, (MW)w) were used to describe the molecular composition of the samples. The samples can be roughly divided in three groups. Group 1 contains samples from managed meadow 40-50cm and stream water, which are characterized by high saturation compared to samples from group 2 including agricultural samples and samples from the surface meadow (0-5cm), which held more nitrogen containing and aromatic compounds. Samples from both forested sites (group 3) are characterized by higher molecular weight and O/C ratio. Environmental parameters vary between sites and among these parameters pH and nitrate significantly affect chemical composition of DOM. Results indicate that most DOM in streams is of terrestrial origin. However, 120 molecular formulae were detected only in streams and not in any of the soil samples. These compounds share molecular formulae with peptides, unsaturated aliphatics and saturated FA-CHO/FA-CHOX. Compounds only found in soil samples are much more aromatic, have more double bonds and a much lower H/C ratio but higher oxygen content, which indicates the availability of fresh plant material and less microbial processed material compared to stream samples. Copyright

  3. Estimation of nutrients and organic matter in Korean swine slurry using multiple regression analysis of physical and chemical properties.

    Science.gov (United States)

    Suresh, Arumuganainar; Choi, Hong Lim

    2011-10-01

    Swine waste land application has increased due to organic fertilization, but excess application in an arable system can cause environmental risk. Therefore, in situ characterizations of such resources are important prior to application. To explore this, 41 swine slurry samples were collected from Korea, and wide differences were observed in the physico-biochemical properties. However, significant (Phydrometer, EC meter, drying oven and pH meter were found useful to estimate Mn, Fe, Ca, K, Al, Na, N and 5-day biochemical oxygen demands (BOD₅) at improved R² values of 0.83, 0.82, 0.77, 0.75, 0.67, 0.47, 0.88 and 0.70, respectively. The results from this study suggest that multiple property regressions can facilitate the prediction of micronutrients and organic matter much better than a single property regression for livestock waste. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Mercury transformations in resuspended contaminated sediment controlled by redox conditions, chemical speciation and sources of organic matter

    Science.gov (United States)

    Zhu, Wei; Song, Yu; Adediran, Gbotemi A.; Jiang, Tao; Reis, Ana T.; Pereira, Eduarda; Skyllberg, Ulf; Björn, Erik

    2018-01-01

    Mercury (Hg) contaminated sediments can be significant sources of Hg in aquatic ecosystems and, through re-emission processes, to the atmosphere. Transformation and release of Hg may be enhanced by various sediment perturbation processes, and controlling biogeochemical factors largely remain unclear. We investigated how rates of Hg transformations in pulp-fiber enriched sediment contaminated by Hg from chlor-alkali industry were controlled by (i) transient redox-changes in sulfur and iron chemistry, (ii) the chemical speciation and solubility of Hg, and (iii) the sources and characteristics of organic matter (OM). Sediment-bottom water microcosm systems were exposed to four combinations of air and nitrogen gas for a total time of 24 h. The treatments were: 24 h N2, 0.5 h air + 23.5 h N2, 4 h air + 20 h N2 and 24 h of air exposure. As a result of these treatments, microcosms spanned a wide range of redox potential, as reflected by the dissolved sulfide concentration range of ≤0.3-97 μM. Four different chemical species of inorganic divalent Hg (HgII) and methyl mercury (MeHg), enriched in different Hg isotope tracers, were added to the microcosms: 201Hg(NO3)2(aq), 202HgII adsorbed to OM (202HgII-OM(ads)), 198HgII as microcrystalline metacinnabar (β-198HgS(s)) and Me204HgCl(aq). Microcosm systems were composed of bottom water mixed with sediment taken at 0-2, 0-5 and 0-10 cm depth intervals. The composition of OM varied with sediment depth such that compared to deeper sediment, the 0-2 cm depth-interval had a 2-fold higher contribution of labile OM originating from algal and terrestrial inputs, serving as metabolic electron-donors for microorganisms. The potential methylation rate constant (kmeth) of Hg tracers and net formation of ambient MeHg (MeHg/THg molar ratio) increased up to 50% and 400%, respectively at intermediate oxidative conditions, likely because of an observed 2-fold increase in sulfate concentration stimulating the activity of sulfate reducing

  5. Gradual and stepwise pyrolyses of insoluble organic matter from the Murchison meteorite revealing chemical structure and isotopic distribution

    Science.gov (United States)

    Okumura, Fumiaki; Mimura, Koichi

    2011-11-01

    To study the detailed structural and isotopic heterogeneity of the insoluble organic matter (IOM) of the Murchison meteorite, we performed two types of pyrolytic experiments: gradual pyrolysis and stepwise pyrolysis. The pyrolysates from the IOM contained 5 specific organic groups: aliphatic hydrocarbons, aromatic hydrocarbons, sulfur-bearing compounds, nitrogen-bearing compounds, and oxygen-bearing compounds. The release temperatures and the compositions of these pyrolysates demonstrated that the IOM is composed of a thermally unstable part and a thermally stable part. The thermally unstable part mainly served as the linkage and substituent portion that bound the thermally stable part, which was dispersed throughout the IOM. The linkage and substituent portion consisted of aliphatic hydrocarbons from C 4 to C 8, aromatic hydrocarbons with up to 6 rings, sulfo and thiol groups (the main reservoirs of sulfur in the IOM), and carboxyl and hydroxyl groups (the main reservoirs of oxygen). However, the thermally stable part was composed of polycyclic aromatic hydrocarbons (PAHs) containing nitrogen heterocycles in the IOM. Isotopic data showed that the aliphatic and aromatic hydrocarbons in the linkage and substituent portion were rich in D and 13C, while the thermally stable part was deficient in D and 13C. The structural and isotopic features suggested that the IOM was formed by mixing sulfur- and oxygen-bearing compounds rich in D and 13C (e.g., polar compounds in the interstellar medium (ISM)) and nitrogen-bearing PAHs deficient in D and 13C (e.g., polymerized compounds in the ISM).

  6. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces

    KAUST Repository

    Chassé , Alexander W.; Ohno, Tsutomu; Higgins, Steven R.; Amirbahman, Aria; Yildirim, Nadir; Parr, Thomas B.

    2015-01-01

    © 2015 American Chemical Society. The adsorption of dissolved organic matter (DOM) to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Although equilibrium studies have described some of the factors controlling this process, the molecular-scale description of the adsorption process has been more limited. Chemical force spectroscopy revealed differing adhesion strengths of DOM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The DOM was characterized using ultrahigh-resolution negative ion mode electrospray ionization Fourier Transform ion cyclotron resonance mass spectrometry. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of DOM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the DOM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups result in the most stable bond to the mineral surface. We conceptualize these results using a layer-by-layer "onion" model of organic matter stabilization on soil mineral surfaces.

  7. Chemical Force Spectroscopy Evidence Supporting the Layer-by-Layer Model of Organic Matter Binding to Iron (oxy)Hydroxide Mineral Surfaces

    KAUST Repository

    Chassé, Alexander W.

    2015-08-18

    © 2015 American Chemical Society. The adsorption of dissolved organic matter (DOM) to metal (oxy)hydroxide mineral surfaces is a critical step for C sequestration in soils. Although equilibrium studies have described some of the factors controlling this process, the molecular-scale description of the adsorption process has been more limited. Chemical force spectroscopy revealed differing adhesion strengths of DOM extracted from three soils and a reference peat soil material to an iron (oxy)hydroxide mineral surface. The DOM was characterized using ultrahigh-resolution negative ion mode electrospray ionization Fourier Transform ion cyclotron resonance mass spectrometry. The results indicate that carboxyl-rich aromatic and N-containing aliphatic molecules of DOM are correlated with high adhesion forces. Increasing molecular mass was shown to decrease the adhesion force between the mineral surface and the DOM. Kendrick mass defect analysis suggests that mechanisms involving two carboxyl groups result in the most stable bond to the mineral surface. We conceptualize these results using a layer-by-layer "onion" model of organic matter stabilization on soil mineral surfaces.

  8. The destruction of organic matter

    CERN Document Server

    Gorsuch, T T

    1970-01-01

    International Series of Monographs in Analytical Chemistry, Volume 39: The Destruction of Organic Matter focuses on the identification of trace elements in organic compounds. The monograph first offers information on the processes involved in the determination of trace elements in organic matters, as well as the methods not involving complete destruction of these elements. The text surveys the sources of errors in the processes responsible in pinpointing elements in organic compounds. These processes include sampling, disruption of the samples, manipulation, and measurements. The book

  9. Correlation between Soil Organic Matter, Total Organic Matter and ...

    African Journals Online (AJOL)

    A total of four sites distributed in different soils of Kelantan State, Malaysia was identified for the study. Soils were collected by depth interval of 0-10cm, 10-20cm and 20-30cm. The correlation of soil organic matter (SOM) content, total organic carbon (TOC) content, water content and soils texture for industrial area at ...

  10. Chemical composition and speciation of particulate organic matter from modern residential small-scale wood combustion appliances.

    Science.gov (United States)

    Czech, Hendryk; Miersch, Toni; Orasche, Jürgen; Abbaszade, Gülcin; Sippula, Olli; Tissari, Jarkko; Michalke, Bernhard; Schnelle-Kreis, Jürgen; Streibel, Thorsten; Jokiniemi, Jorma; Zimmermann, Ralf

    2018-01-15

    Combustion technologies of small-scale wood combustion appliances are continuously developed decrease emissions of various pollutants and increase energy conversion. One strategy to reduce emissions is the implementation of air staging technology in secondary air supply, which became an established technique for modern wood combustion appliances. On that account, emissions from a modern masonry heater fuelled with three types of common logwood (beech, birch and spruce) and a modern pellet boiler fuelled with commercial softwood pellets were investigated, which refer to representative combustion appliances in northern Europe In particular, emphasis was put on the organic constituents of PM2.5, including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs) and phenolic species, by targeted and non-targeted mass spectrometric analysis techniques. Compared to conventional wood stoves and pellet boilers, organic emissions from the modern appliances were reduced by at least one order of magnitude, but to a different extent for single species. Hence, characteristic ratios of emission constituents and emission profiles for wood combustion identification and speciation do not hold for this type of advanced combustion technology. Additionally, an overall substantial reduction of typical wood combustion markers, such as phenolic species and anhydrous sugars, were observed. Finally, it was found that slow ignition of log woods changes the distribution of characteristic resin acids and phytosterols as well as their thermal alteration products, which are used as markers for specific wood types. Our results should be considered for wood combustion identification in positive matrix factorisation or chemical mass balance in northern Europe. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Feed and organic matter

    DEFF Research Database (Denmark)

    Dalsgaard, Anne Johanne Tang

    2011-01-01

    impact on the receiving water body by reducing dissolved oxygen concentrations and increasing sedimentation. Within aquaculture systems, a high organic load may affect fish health and performance directly (e.g., gill disease) as well as indirectly (proliferation of pathogenic bacteria and parasites......, reduction of dissolved oxygen concentrations, etc.). In recirculating aquaculture systems (RAS), a high organic load caused by limited water exchange may affect biofilter performance by favouring heterotrophic bacteria at the expense of autotrophic, nitrifying bacteria. Organic waste in RAS primarily...... originates from undigested feed, but also metabolic losses, mucus, dead tissue, feed waste and intake water may contribute. The nutrient composition of the feed affects the quantity and composition of the organic (undigested) waste, and including for example plant protein ingredients may affect...

  12. Repeated applications of compost and manure mainly affect the size and chemical nature of particulate organic matter in a loamy soil after 8 years

    Science.gov (United States)

    Peltre, Clement; Dignac, Marie-France; Doublet, Jeremy; Plante, Alain; Houot, Sabine

    2013-04-01

    Land application of exogenous organic matter (EOM) of residual origin can help to maintain or increase soil organic carbon (SOC) stocks. However, it remains necessary to quantify and predict the soil C accumulation and to determine under which form the C accumulates. Changes to the chemical composition of soil organic matter (SOM) after repeated applications of composts and farmyard manure were investigated in a field experiment (Qualiagro experiment, Ile-de-France) after 8 years of applications of green waste and sludge compost (GWS), municipal solid waste compost (MSW), biowaste compost (BIOW) or farmyard manure (FYM). The soil was fractionated into particulate organic matter >50 µm (POM), a heavy fraction >50 µm and a 0-50 µm fraction demineralized with hydrofluoric acid (HF). Repeated EOM applications significantly increased total SOC stocks, the C amount in the POM fraction and to a less extent in the 0-50 µm fraction compared to the reference treatment. Compost applications accumulated C preferentially under the form of coarse organic matter of size >50 µm, whereas the FYM accumulated similar C proportions of size >50 µm and 0-50 µm, which was attributed to the presence in the FYM of a fraction of labile C stimulating microbial activity and producing humified by-products together with a fraction of stabilized C directly alimenting the humified fraction of SOC. Pyrolysis-GC/MS and DRIFT spectroscopy revealed enrichment in lignin in the POM fractions of amended soils with GWS, BIOW and FYM. In the soil receiving MSW compost, the pyrolysate of the POM fraction revealed the presence of plastics originating from the MSW compost. A lower C mineralization during laboratory incubation was found for the POM fractions of amended soils compared with the POM from reference soil. This feature was related to a lower ratio of (furfural+acetic acid) / pyrole pyrolysis products in POM of amended vs. reference plots, indicating a higher degree of recalcitrance.. The POM

  13. Generation of dissolved organic matter and byproducts from activated sludge during contact with sodium hypochlorite and its implications to on-line chemical cleaning in MBR.

    Science.gov (United States)

    Cai, Weiwei; Liu, Jiaqi; Zhang, Xiangru; Ng, Wun Jern; Liu, Yu

    2016-11-01

    On-line chemical cleaning of membranes with sodium hypochlorite (NaClO) has been commonly employed for maintaining a constant permeability of membrane bioreactor (MBR) due to its simple and efficient operation. However, activated sludge is inevitably exposed to NaClO during this cleaning process. In spite of the broad applications of on-line chemical cleaning in MBR such as chemical cleaning-in-place (CIP) and chemical enhanced backwash (CEB), little information is currently available for the release of emerging dissolved organic matter (DOM) and byproducts from this prevalent practice. Therefore, in this study, activated sludge suspended in a phosphate buffered saline solution was exposed to different doses of NaClO in order to determine the generation of potential DOM and byproducts. The results showed the occurrence of significant DOM release (up to 24.7 mg/L as dissolved organic carbon) after exposure to NaClO for 30 min. The dominant components of the released DOM were characterized to be humic acid-like as well as protein-like substances by using an excitation-emission matrix fluorescence spectrophotometer. Furthermore, after the contact of activated sludge with NaClO, 19 kinds of chlorinated and brominated byproducts were identified by ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, eight of which were confirmed and characterized with standard compounds. Many byproducts were found to be halogenated aromatic compounds, including halopyrroles and halo(hydro)benzoquinones, which had been reported to be significantly more toxic than the halogenated aliphatic ones. Consequently, this study offers new insights into the practice of on-line chemical cleaning, and opens up a window to re-examine the current operation of MBR by looking into the generation of micropollutants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Chemical characteristics and source apportionment of fine particulate organic carbon in Hong Kong during high particulate matter episodes in winter 2003

    Science.gov (United States)

    Li, Yun-Chun; Yu, Jian Zhen; Ho, Steven Sai Hang; Schauer, James J.; Yuan, Zibing; Lau, Alexis K. H.; Louie, Peter K. K.

    2013-02-01

    PM2.5 samples were collected at six general stations and one roadside station in Hong Kong in two periods of high particulate matter (PM) in 2003 (27 October-4 November and 30 November-13 December). The highest PM2.5 reached 216 μg m- 3 during the first high PM period and 113 μg m- 3 during the second high PM period. Analysis of synoptic weather conditions identified individual sampling days under dominant influence of one of three types of air masses, that is, local, regional and long-range transported (LRT) air masses. Roadside samples were discussed separately due to heavy influences from vehicular emissions. This research examines source apportionment of fine organic carbon (OC) and contribution of secondary organic aerosol on high PM days under different synoptic conditions. Six primary OC (POC) sources (vehicle exhaust, biomass burning, cooking, cigarette smoke, vegetative detritus, and coal combustion) were identified on the basis of characteristic organic tracers. Individual POC source contributions were estimated using chemical mass balance model. In the roadside and the local samples, OC was dominated by the primary sources, accounting for more than 74% of OC. In the samples influenced by regional and LRT air masses, secondary OC (SOC), which was approximated to be the difference between the total measured OC and the apportioned POC, contributed more than 54% of fine OC. SOC was highly correlated with water-soluble organic carbon and sulfate, consistent with its secondary nature.

  15. Molecular characterization of macrophyte-derived dissolved organic matters and their implications for lakes

    Science.gov (United States)

    Chemical properties of whole organic matter (OM) and its dissolved organic matter (DOM) fraction from six dominant macrophytes in Lake Dianchi were comparatively characterized, and their environmental implications were discussed. Significant differences in chemical composition of the OM samples were...

  16. Chemical characteristics of dissolved organic matter (DOM) in relation to heavy metal concentrations in soil water from boreal peatlands after clear-cut harvesting

    Science.gov (United States)

    Kiikkilä, O.; Nieminen, T.; Starr, M.; Ukonmaanaho, L.

    2012-04-01

    Boreal peatlands form an important terrestrial carbon reserve and are a major source of dissolved organic matter (DOM) to surface waters, particularly when disturbed through forestry practices such as draining or timber harvesting. Heavy metals show a strong affinity to organic matter and so, along with DOM, heavy metals can be mobilized and transported from the soil to surface waters and sediments where they may become toxic to aquatic organisms and pass up the food chain. The complexation of heavy metals with DOM can be expected to be related and determined by the chemical characteristics of DOM and oxidation/reducing conditions in the peat. We extracted interstitial water from peat samples and determined the concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and Al, Cu, Zn and Fe in various fractions of DOM isolated by adsorption properties (XAD-8 fractionation) and molecular-weight (ultrafiltration). The peat samples were taken from 0-30 and 30-50 cm depth in drained peatland catchments two years after whole-tree or stem-only clear-cut harvesting (Scots pine or Norway spruce) had been carried out. The samples from the upper layer had been subject to alternating saturation/aeration conditions while the deeper layer had been continuously under the water table. The fractionation of DOC and DON according to both adsorption properties and molecular-weight fractions clearly differed between the upper and lower peat layers. While the hydrophobic acid fraction contained proportionally more DOC and DON than the hydrophilic acid fraction in the upper peat layer the results were vice versa in the lower peat layer. High-molecular-weight compounds (> 100 kDa) were proportionally more abundant in the upper and low-molecular-weight compounds (< 1 kDa) in the lower peat layer. These differences are assumed to reflect differences in the aerobic/ anaerobic conditions and degree of decomposition between the two layers. The concentrations of Zn, Al

  17. Differential chemical fractionation of dissolved organic matter during sorption by Fe mineral phases in a tropical soil from the Luquillo Critical Zone Observatory

    Science.gov (United States)

    Plante, A. F.; Coward, E.; Ohno, T.; Thompson, A.

    2017-12-01

    Fe-bearing mineral phases contribute substantially to adsorption and stabilization of soil organic matter (SOM), due largely to their high specific surface area (SSA) and reactivity. While the importance of adsorption onto mineral surfaces has been well-elucidated, selectivity of various mineral and organic phases remains poorly understood. The goals of this work were to: 1) quantify the contributions of Fe-minerals of varying crystallinity to dissolved organic matter (DOM) sorption, and 2) characterize the molecular fractionation of DOM induced by reactions at the mineral interface, using a highly-weathered Oxisol from the Luquillo Critical Zone Observatory (LCZO). Three selective dissolution experiments targeting Fe-mineral phases were followed by specific surface area (SSA) analysis of the residues and characterization of extracted DOM by high resolution mass spectrometry (FT-ICR-MS). Fe-depleted extraction residue samples, untreated control soil samples, and Fe-enriched ferrihydrite-coated soil samples were then subjected to a batch sorption experiment with litter-derived DOM. Results of selective dissolution experiments indicated that a substantial proportion of soil SSA was derived from extracted Fe-bearing phases, and FT-ICR-MS analysis of extracted DOM revealed distinct chemical signatures. Sorbed C concentrations were well correlated with Fe contents induced by treatments, and thus SSA. Molecular characterization of the DOM post-sorption indicated that poorly crystalline Fe phases preferentially adsorbed highly unsaturated aromatic compounds, and higher-crystallinity Fe phases were associated with more aliphatic compounds. These findings suggests that molecular fractionation via organomineral complexation may act as a physicochemical filter of DOM released to the critical zone.

  18. Radionuclide - Soil Organic Matter Interactions

    DEFF Research Database (Denmark)

    Carlsen, Lars

    1985-01-01

    Interactions between soil organic matter, i.e. humic and fulvic acids, and radionuclides of primary interest to shallow land burial of low activity solid waste have been reviewed and to some extent studied experimentally. The radionuclides considered in the present study comprise cesium, strontium...

  19. POM Pulses: Characterizing the Physical and Chemical Properties of Particulate Organic Matter (POM) Mobilized by Large Storm Events and its Influence on Receiving Fluvial Systems

    Science.gov (United States)

    Johnson, E. R.; Rowland, R. D.; Protokowicz, J.; Inamdar, S. P.; Kan, J.; Vargas, R.

    2016-12-01

    Extreme storm events have tremendous erosive energy which is capable of mobilizing vast amounts of material from watershed sources into fluvial systems. This complex mixture of sediment and particulate organic matter (POM) is a nutrient source, and has the potential to impact downstream water quality. The impact of POM on receiving aquatic systems can vary not only by the total amount exported but also by the various sources involved and the particle sizes of POM. This study examines the composition of POM in potential sources and within-event POM by: (1) determining the amount and quality of dissolved organic matter (DOM) that can be leached from coarse, medium and fine particle classes; (2) assessing the C and N content and isotopic character of within-event POM; and (3) coupling physical and chemical properties to evaluate storm event POM influence on stream water. Storm event POM samples and source sediments were collected from a forested headwater catchment (second order stream) in the Piedmont region of Maryland. Samples were sieved into three particle classes - coarse (2mm-1mm), medium (1mm-250µm) and fine (solid state event and source material. Future work will include examination of microbial communities associated with POM particle size classes. Physical size class separation of within-event POM exhibited differences in C:N ratios, δ15N composition, and extracted DOM lability. Smaller size classes exhibited lower C:N ratios, more enriched δ15N and more recalcitrant properties in leached DOM. Source material had varying C:N ratios and contributions to leached DOM. These results indicate that both source and size class strongly influence the POM contribution to fluvial systems during large storm events.

  20. Organic matter in the universe

    CERN Document Server

    Kwok, Sun

    2012-01-01

    Authored by an experienced writer and a well-known researcher of stellar evolution, interstellar matter and spectroscopy, this unique treatise on the formation and observation of organic compounds in space includes a spectroscopy refresher, as well as links to geological findings and finishes with the outlook for future astronomical facilities and solar system exploration missions. A whole section on laboratory simulations includes the Miller-Urey experiment and the ultraviolet photolysis of ices.

  1. Seasonal changes in the chemical quality and biodegradability of dissolved organic matter exported from soils to streams in coastal temperate rainforest watersheds

    Science.gov (United States)

    Jason B. Fellman; Eran Hood; David V. D' Amore; Richard T. Edwards; Dan White

    2009-01-01

    The composition and biodegradability of streamwater dissolved organic matter (DOM) varies with source material and degree of transformation. We combined PARAFAC modeling of fluorescence excitation-emission spectroscopy and biodegradable dissolved organic carbon (BDOC) incubations to investigate seasonal changes in the lability of DOM along a soil-stream continuum in...

  2. Modification of chemical and conformational properties of natural organic matter by click chemistry as revealed by ESI-Orbitrap mass spectrometry.

    Science.gov (United States)

    Nebbioso, Antonio; Piccolo, Alessandro

    2015-11-01

    A click reaction is reported here for the first time as a useful technique to control the conformational stability of natural organic matter (NOM) suprastructures. Click conjugates were successfully formed between a previously butynylated NOM hydrophobic fraction and a hydrophilic polyethylene glycol (PEG)-amino chain. The click products were shown by size exclusion chromatography (HPSEC) hyphenated with Orbitrap mass spectrometry (MS) in electrospray ionization (ESI) (+), while precursors were visible in ESI (-). Despite their increase in molecular weight, HPSEC elution of click conjugates occurred after that of precursors, thus showing their departure from the NOM supramolecular association. This indicates that the click-conjugated NOM molecules were varied in their hydrophilic and cationic character and lost the capacity to accommodate in the original hydrophobic suprastructures. The most abundant product had the C16H30O5N4 formula, a click conjugate of butanoic acid, while other products were short-chained (C4-C8) linear unsaturated and hydroxylated carboxylic acids. Tandem MS revealed formation of triazole rings in clicked conjugates and their two fragmentations at the ester and the C-N alkyl-aryl bonds. The behavior of NOM molecules modified by click chemistry confirms that hydrophobicity and ionic charge of humic molecules play a pivotal role in stabilizing intermolecular forces in NOM. Moreover, the versatility of the click reaction may become useful to decorate NOM molecules with a variety of substrates, in order to alter NOM conformational and chemical properties and diversify its applications in the environment.

  3. Chemical and biochemical properties of Stagnic Albeluvisols organic matter as result of long-term agricultural management and native forest ecosystem

    Science.gov (United States)

    Astover, Alar; Kõlli, Raimo; Wojciech Szajdak, Lech

    2010-05-01

    Soil organic matter (SOM) is considered to be as the most important factor in soil forming, development and continuous functioning. Sequestrated into SOM organic carbon concentrations, pools and residence time in soil, as well acting intensity of interconnected with SOM edaphon are soil type specific or characteristic to certain soil types. In depending on soil moisture regime, calcareousness and clay content for each soil type certain soil organic carbon (SOC) retaining capacity and its vertical distribution pattern are characteristic. However, land use change (crop rotation, continuous cropping, no-tillage, melioration, rewetting) has greatest influence mainly on fabric of epipedon and biological functions of soil cover. Stagnic Albeluvisols are largely distributed at Tartu County. They form here more than half from arable soils. The establishment of long-term field trial and forest research area in these regions for biochemical analysis of Stagnic Albeluvisols' organic matter is in all respects justified. In 1989, an international long-term experiment on the organic nitrogen or IOSDV (Internationale Organische Stickstoffdauerdiingungsversuche) with three-field crop rotation (potato - spring wheat - spring barley) was started at Eerika near Tartu (58° 22.5' N; 26° 39.8' E) on Stagnic Albeluvisol. The main aims of this study were to determine the long-term effects of cropping systems on physico-chemical properties of soils and their productivity. The design of this field experiment is similar to other European network of IOSDV experiments. Before the establishment of this experiment in 1989 it was in set-aside state (5-6 years) as field-grass fallow. It was used as arable land in condition of state farm during 1957-83. Average agrochemical characteristics of the plough horizon of soil in the year of establishment were the following: humus content 17.1 g kg-1, total nitrogen content 0.9 g kg-1, C:N ratio 11 and pHKCl 6.3. DL soluble phosphorus content was 44 mg

  4. Organic matters: investigating the sources, transport, and fate of organic matter in Fanno Creek, Oregon

    Science.gov (United States)

    Sobieszczyk, Steven; Keith, Mackenzie K.; Goldman, Jami H.; Rounds, Stewart A.

    2015-01-01

    The term organic matter refers to the remnants of all living material. This can include fallen leaves, yard waste, animal waste, downed timber, or the remains of any other plant and animal life. Organic matter is abundant both on land and in water. Investigating organic matter is necessary for understanding the fate and transport of carbon (a major constituent of organic matter).

  5. Changes in soil physical and chemical properties following organic matter removal and compaction: 20-year response of the aspen Lake-States Long Term Soil Productivity installations

    Science.gov (United States)

    Robert A. Slesak; Brian J. Palik; Anthony W. D' Amato; Valerie J. Kurth

    2017-01-01

    Soil functions that control plant resource availability can be altered by management activities such as increased organic matter (OM) removal and soil compaction during forest harvesting. The Long Term Soil Productivity study was established to evaluate how these practices influence soil and site productivity using experimental treatments that span a range of forest...

  6. Differences in chemical composition of soil organic matter in natural ecosystems from different climatic regions: a pyrolysis-GC/MS study

    NARCIS (Netherlands)

    Vancampenhout, K.; Wouters, K.; Vos, de B.; Buurman, P.; Swennen, R.; Deckers, J.

    2009-01-01

    Soil organic matter (SOM) is a key factor in ecosystem dynamics. A better understanding of the global relationship between environmental characteristics, ecosystems and SOM chemistry is vital in order to assess its specific influence on carbon cycles. This study compared the composition of extracted

  7. Relationship between chemical structure of soil organic matter and intra-aggregate pore structure: evidence from X-ray computed micro-tomography

    Science.gov (United States)

    Kravchenko, Alexandra; Grandy, Stuart A.

    2014-05-01

    Understanding chemical structure of soil organic matter (SOM) and factors that affect it are vital for gaining understanding of mechanisms of C sequestration by soil. Physical protection of C by adsorption to mineral particles and physical disconnection between C sources and microbial decomposers is now regarded as the key component of soil C sequestration. Both of the processes are greatly influenced by micro-scale structure and distribution of soil pores. However, because SOM chemical structure is typically studied in disturbed (ground and sieved) soil samples the experimental evidence of the relationships between soil pore structure and chemical structure of SOM are still scarce. Our study takes advantage of the X-ray computed micro-tomography (µ-CT) tools that enable non-destructive analysis of pore structure in intact soil samples. The objective of this study is to examine the relationship between SOM chemical structure and pore-characteristics in intact soil macro-aggregates from two contrasting long-term land uses. The two studied land use treatments are a conventionally tilled corn-soybean-wheat rotation treatment and a native succession vegetation treatment removed from agricultural use >20 years ago. The study is located in southwest Michigan, USA, on sandy-loam Typic Hapludalfs. For this study we used soil macro-aggregates 4-6 mm in size collected at 0-15 cm depth. The aggregate size was selected so as both to enable high resolution of µ-CT and to provide sufficient amount of soil for C measurements. X-ray µ-CT scanning was conducted at APS Argonne at a scanning resolution of 14 µm. Two scanned aggregates (1 per treatment) were used in this preliminary study. Each aggregate was cut into 7 "geo-referenced" sections. Analyses of pore characteristics in each section were conducted using 3DMA and ImageJ image analysis tools. SOM chemistry was analyzed using pyrolysis/gas chromatography-mass spectroscopy. Results demonstrated that the relationships

  8. Agriculture Organic Matter and Chicken Manure

    Directory of Open Access Journals (Sweden)

    Süleyman Taban

    2013-11-01

    Full Text Available Undo ubtedly organic matter content of soils is one of theim portant factor for high quality and abundant crop production. In addition to improve the physical properties ofsoil, organic matter contributest ocrop production viabeing energy source formicro-organisms in soiland contained plantnutrients. Fiftypercent of theagri cultures oil contains 1-2 % organicmatter in Turkey.In addition to being a sourceof organic matter, organic poultry manurefertilizer isricherthan other organic fertilizerse specially nitrogen content. It is possible to eliminate poultry manure based salt stress and disease factors with composting process in proper conditions.

  9. Organic matter in central California radiation fogs.

    Science.gov (United States)

    Herckes, Pierre; Lee, Taehyoung; Trenary, Laurie; Kang, Gongunn; Chang, Hui; Collett, Jeffrey L

    2002-11-15

    Organic matter was studied in radiation fogs in the San Joaquin Valley of California during the California Regional Particulate Air Quality Study (CRPAQS). Total organic carbon (TOC) concentrations ranged from 2 to 40 ppm of C. While most organic carbon was found in solution as dissolved organic carbon (DOC), 23% on average was not dissolved inside the fog drops. We observe a clear variation of organic matter concentration with droplet size. TOC concentrations in small fog drops (fogwater, consistent with the enrichment of the organic matter in smaller fog drops with lower terminal settling velocities.

  10. (Tropical) soil organic matter modelling: problems and prospects

    NARCIS (Netherlands)

    Keulen, van H.

    2001-01-01

    Soil organic matter plays an important role in many physical, chemical and biological processes. However, the quantitative relations between the mineral and organic components of the soil and the relations with the vegetation are poorly understood. In such situations, the use of models is an

  11. Organic matter and soil moisture content and double cropping with organic matter sourceplants

    OpenAIRE

    John Bako Baon; Aris Wibawa

    2005-01-01

    Double cropping of coffee with organic matter source plants is thought to increase organic matter content of soil. This study examined the effect of double cropping of coffee and organic matter source plants on soil organic matter content and yield of coffee plants. Arabica coffee trees in Andungsari Experimental Station (Bondowoso district), 1400 m asl. and climate type C; and Robusta coffee trees in Sumberasin Experimental Station (Malang district), 550 m asl. and climate type C, were used ...

  12. Cycling downwards - dissolved organic matter in soils

    NARCIS (Netherlands)

    Kaiser, K.; Kalbitz, K.

    2012-01-01

    Dissolved organic matter has been recognized as mobile, thus crucial to translocation of metals, pollutants but also of nutrients in soil. We present a conceptual model of the vertical movement of dissolved organic matter with soil water, which deviates from the view of a chromatographic stripping

  13. Podzolisation and soil organic matter dynamics

    NARCIS (Netherlands)

    Buurman, P.; Jongmans, A.G.

    2005-01-01

    Present models of podzolisation emphasize the mobilization and precipitation of dissolved organic matter. together with Al(-silicates) and Fe. Such models cannot explain the dominance of pellet-like organic matter in most boreal podzols and in well-drained podzols outside the boreal zone, and the

  14. When Organization Fails: Why Authority Matters

    DEFF Research Database (Denmark)

    Blaschke, Steffen

    2015-01-01

    Review of: James R. Taylor and Elizabeth J. Van Every / When Organization Fails: Why Authority Matters. (New York: Routledge, 2014. 220 pp. ISBN: 978 0415741668)......Review of: James R. Taylor and Elizabeth J. Van Every / When Organization Fails: Why Authority Matters. (New York: Routledge, 2014. 220 pp. ISBN: 978 0415741668)...

  15. The Influence of Land-Use Change on Soil and Dissolved Organic Matter Age, Lability, and Chemical Characteristics in Brazilian Oxisols

    Science.gov (United States)

    James, J. N.; Harrison, R. B.; Gross, C. D.; Dwivedi, P.; Myers, T.; Butman, D. E.

    2017-12-01

    Recent advances in freshwater research indicate that the age of carbon exported from major rivers globally increases with greater human disturbance in the watershed. This implies that human land-use can release old, previously mineral-associated C into solution with subsequent export to groundwater and ultimately freshwater systems where terrestrial organic matter is either mineralized to CO2, stored in aquatic sediments, or exported to the ocean. It is important to understand the mechanisms that cause the release of mineral-bound soil organic matter (SOM) into solution in response to human disturbance and land-use change. To better characterize the response of the total soil organic matter (SOM) pool to disturbance, this study examines the interactions between dissolved and bulk soil pools in response to conversion of Brazilian Cerrado (savannah forest) to Eucalyptus plantations. Water-extractable organic matter (WEOM) was obtained from soil samples down to 150 cm at 4 sites in Sao Paulo State, Brazil. These WEOM samples were characterized using fluorescence and NMR spectroscopy, incubated to assess biolability, and carbon-dated. Simultaneously, bulk mineral soil samples were analyzed for microbial biomass, carbon content and age, and characterized using Fourier Transform Infrared Spectroscopy. FTIR spectra of SOM were obtained by washing subsamples with sodium hypochlorite and subtracting the subsequent mineral matrix spectra from bulk soil spectra. Preliminary results show that microbial biomass decreases much more quickly with depth than WEOM, suggesting that C released into solution from deeper horizons may be less likely to be intercepted, and thus preferentially leached to groundwater. Native Cerrado forests had substantially more roots compared to Eucalyptus, and also released substantially larger quantities of WEOM from their O horizons. Furthermore, the age of WEOM released under Eucalyptus forest was more similar in age to bulk SOM, while Cerrado forest

  16. Distribution of chemical compartments of soil organic matter and c stocks of a cambisol from south Brazil as affected by Pinus afforestation

    Directory of Open Access Journals (Sweden)

    Henrique Cesar Almeida

    2012-01-01

    Full Text Available Distribution and stocks of soil organic matter (SOM compartments after Pinus monoculture introduction in a native pasture area of a Cambisol, Santa Catarina, Brazil, were investigated. Pinus introduction increased soil acidity, content of exchangeable Al+3 and diminished soil nutrients. Nevertheless, soil C stock increased in all humic fractions of the 0-5 cm layer after Pinus afforestation. In the subsurface, the vegetation change only promoted SOM redistribution from the NaOH-extractable humic substances to a less hydrophobic humin fraction. Under Pinus, soil organo-mineral interactions were relevant up to a 15 cm depth, while in pasture environment, this mechanism occurred mainly in the surface layer.

  17. Mapping Soil Organic Matter with Hyperspectral Imaging

    Science.gov (United States)

    Moni, Christophe; Burud, Ingunn; Flø, Andreas; Rasse, Daniel

    2014-05-01

    Soil organic matter (SOM) plays a central role for both food security and the global environment. Soil organic matter is the 'glue' that binds soil particles together, leading to positive effects on soil water and nutrient availability for plant growth and helping to counteract the effects of erosion, runoff, compaction and crusting. Hyperspectral measurements of samples of soil profiles have been conducted with the aim of mapping soil organic matter on a macroscopic scale (millimeters and centimeters). Two soil profiles have been selected from the same experimental site, one from a plot amended with biochar and another one from a control plot, with the specific objective to quantify and map the distribution of biochar in the amended profile. The soil profiles were of size (30 x 10 x 10) cm3 and were scanned with two pushbroomtype hyperspectral cameras, one which is sensitive in the visible wavelength region (400 - 1000 nm) and one in the near infrared region (1000 - 2500 nm). The images from the two detectors were merged together into one full dataset covering the whole wavelength region. Layers of 15 mm were removed from the 10 cm high sample such that a total of 7 hyperspectral images were obtained from the samples. Each layer was analyzed with multivariate statistical techniques in order to map the different components in the soil profile. Moreover, a 3-dimensional visalization of the components through the depth of the sample was also obtained by combining the hyperspectral images from all the layers. Mid-infrared spectroscopy of selected samples of the measured soil profiles was conducted in order to correlate the chemical constituents with the hyperspectral results. The results show that hyperspectral imaging is a fast, non-destructive technique, well suited to characterize soil profiles on a macroscopic scale and hence to map elements and different organic matter quality present in a complete pedon. As such, we were able to map and quantify biochar in our

  18. Characterization and distribution of organic matter using specific physico-chemical methods: A case study of the southeast Adriatic continental and shelf slope (Albania)

    Science.gov (United States)

    Plavšić, Marta; Strmečki, Slađana; Dautović, Jelena; Vojvodić, Vjeročka; Olujić, Goran; Ćosović, Božena

    2012-05-01

    In May 2009, we characterized the organic matter in the area where Albanian shelf riverine plume waters enter the Southern Adriatic Pit region. Due to stable weather and hydrological conditions at the time of sampling a longitudinal thermal front was present around the Albanian shelf break. Our measurements point to the input of inorganic nutrients, including phosphorus (average P-PO4 concentration was 0.71 μg/L) and nitrogen (average as total inorganic nitrogen (TIN) concentration was 25.33 μg/L) due to the intrusion of Levantine Intermediate Water (LIW) through the Otranto Strait. The input of LIW brings high salinity (˜38.7) water that is poor in organic matter content. Low concentrations of dissolved organic carbon (DOC) (0.7 mg C/L) and particulate organic carbon (POC) (0.06 mg C/L), surface active substances (SAS) (in the range from 0.025 to 0.078 mg/L equiv. Triton-X-100) and copper complexing capacity (CuCC) (24 nmol Cu2+/L) were measured in the area. All the values for DOC, POC, SAS and CuCC were significantly lower in the Albanian coastal waters than in the North Adriatic. The measurable influence of the inflowing Albanian rivers was observed from the inverse dependance of the DOC concentrations and salinity data. The Albanian rivers contribute to the elevated nutrient concentrations especially those of silicate, which displayed concentrations up to 380 μg/L in the shallowest coastal station.

  19. Investigating Photosensitized Properties of Natural Organic Matter and Effluent Organic Matter

    KAUST Repository

    Niu, Xi-Zhi

    2013-05-01

    The photosensitized processes significantly enhance photolysis of various chemicals in the aqueous system with dissolved organic matter (DOM) as sensitizer. The excitation of chromophores on the DOM molecule further generates reactive species as triplet states DOM, singlet oxygen, hydroxyl radical, carbonate radical etc. We investigated the photosensitization properties of Beaufort Fulvic Acid, Suwannee River Fulvic Acid, South Platte River Fulvic Acid, and Jeddah wastewater treatment plant effluent organic matter with a sunlight simulator. DOM photochemical properties were characterized by observing their performances in 3DOM*, singlet oxygen, hydroxyl radical production with indirect probing protocols. Sensitized degradation of 0.1 μM and 0.02 μM 2, 4, 6- Trimethylphenol exhibited higher pseudo-first-order rate constant than that of 10 μM. Pre-irradiated DOMs were found to be depressed in photochemical properties. Photolysis of 5 different contaminants: ibuprofen, bisphenol A, acetaminophen, cimetidine, and caffeine were found to be enhanced in the presence of sensitizers. The possible reaction pathways were revealed. Long time irradiance induced change in contaminants degradation kinetics in some DOM solutions, which was proposed to be due to the irradiation initiated indirect transformation of DOMs. Key Words: Photolysis Dissolved Organic Matter, Triplet State DOM, Singlet Oxygen, Hydroxyl Radical, Contaminants Degradation.

  20. LOSS OF ORGANIC CHEMICALS IN SOIL: PURE COMPOUND TREATABILITY STUDIES

    Science.gov (United States)

    Comprehensive screening data on the treatability of 32 organic chemicals in soil were developed. Of the evaluated chemicals, 22 were phenolic compounds. Aerobic batch laboratory microcosm experiments were conducted using two soils: an acidic clay soil with <1% organic matter and ...

  1. Lowering temperature to increase chemical oxidation efficiency: the effect of temperature on permanganate oxidation rates of five types of well defined organic matter, two natural soils, and three pure phase products.

    Science.gov (United States)

    de Weert, J P A; Keijzer, T J S; van Gaans, P F M

    2014-12-01

    In situ chemical oxidation (ISCO) is a soil remediation technique to remove organic pollutants from soil and groundwater with oxidants, like KMnO4. However, also natural organic compounds in soils are being oxidized, which makes the technique less efficient. Laboratory experiments were performed to investigate the influence of temperature on this efficiency, through its effect on the relative oxidation rates - by permanganate - of natural organic compounds and organic pollutants at 16 and 15°C. Specific types of organic matter used were cellulose, oak wood, anthracite, reed - and forest peat, in addition to two natural soils. Dense Non-Aqueous Phase Liquid-tetrachloroethene (DNAPL-PCE), DNAPL trichloroethene (DNAPL-TCE) and a mixture of DNAPL-PCE, -TCE and -hexachlorobutadiene were tested as pollutants. Compared to 16°C, oxidation was slower at 5°C for the specific types of organic matter and the natural soils, with exception of anthracite, which was unreactive. The oxidation rate of DNAPL TCE was lower at 5°C too. However, at this temperature oxidation was fast, implying that no competitive loss to natural organic compounds will be expected in field applications by lowering temperature. Oxidation of DNAPL-PCE and PCE in the mixture proceeded at equal rates at both temperatures, due to the dissolution rate as limiting factor. These results show that applying permanganate ISCO to DNAPL contamination at lower temperatures will limit the oxidation of natural organic matter, without substantially affecting the oxidation rate of the contaminant. This will make such remediation more effective and sustainable in view of protecting natural soil quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. A Novel Type of Oil—generating Organic Matter —Crystal—enclosed Organic Matter

    Institute of Scientific and Technical Information of China (English)

    周中毅; 裴存民; 等

    1992-01-01

    The comparative study of organic matter in carbonate rocks and argillaceous rocks from the same horizon indicates that the organic thermal maturities of carbonate rocks are much lower than those of argillaceous rocks .Ana extensive analysis of extracted and inclused organic matter from the same sample shows that inclused organic matter is different from extracted organic matter,and the thermal maturity of the former is usually lower than that of the latter in terms of biomarker structural parameters.It seems that carbonate mineras could preserve organic matter and retard organic maturation.The inclused organic matter,abundant in most carbonate rocks,will be released from minerals and transformed into oil and gas during the high-thermal maturity stage.

  3. [Effects of forest regeneration patterns on the quantity and chemical structure of soil solution dissolved organic matter in a subtropical forest.

    Science.gov (United States)

    Yuan, Xiao Chun; Lin, Wei Sheng; Pu, Xiao Ting; Yang, Zhi Rong; Zheng, Wei; Chen, Yue Min; Yang, Yu Sheng

    2016-06-01

    Using the negative pressure sampling method, the concentrations and spectral characte-ristics of dissolved organic matter (DOM) of soil solution were studied at 0-15, 15-30, 30-60 cm layers in Castanopsis carlesii forest (BF), human-assisted naturally regenerated C. carlesii forest (RF), C. carlesii plantation (CP) in evergreen broad-leaved forests in Sanming City, Fujian Pro-vince. The results showed that the overall trend of dissolved organic carbon (DOC) concentrations in soil solution was RF>CP>BF, and the concentration of dissolved organic nitrogen (DON) was highest in C. carlesii plantation. The concentrations of DOC and DON in surface soil (0-15 cm) were all significantly higher than in the subsurface (30-60 cm). The aromatic index (AI) was in the order of RF>CP>BF, and as a whole, the highest AI was observed in the surface soil. Higher fluorescence intensity and a short wave absorption peak (320 nm) were observed in C. carlesii plantation, suggesting the surface soil of C. carlesii plantation was rich in decomposed substance content, while the degree of humification was lower. A medium wave absorption peak (380 nm) was observed in human-assisted naturally regenerated C. carlesii forest, indicating the degree of humification was higher which would contribute to the storage of soil fertility. In addition, DOM characte-ristics in 30-60 cm soil solution were almost unaffected by forest regeneration patterns.

  4. Applicability of FTIR-spectroscopy for characterizing waste organic matter

    International Nuclear Information System (INIS)

    Smidt, E.

    2001-12-01

    State and development of waste organic matter were characterized by means of FTIR-spectroscopy. Due to the interaction of infrared light with matter energy is absorbed by chemical functional groups. Chemical preparation steps are not necessary and therefore this method offers a more holistic information about the material. The first part of experiments was focussed on spectra of different waste materials representing various stages of decomposition. Due to characteristics in the fingerprint- region the identity of wastes is provable. Heights of significant bands in the spectrum were measured and relative absorbances were calculated. Changes of relative absorbances indicate the development of organic matter during decomposition. Organic matter of waste samples was compared to organic matter originating from natural analogous processes (peat, soil). The second part of experiments concentrated on a composting process for a period of 260 days. Spectral characteristics of the samples were compared to their chemical, physical and biological data. The change of relative absorbances was reflected by conventional parameters. According to the development of the entire sample humic acids underwent a change as well. For practical use the method offers several possibilities: monitoring of a process, comparison of different processes, quality control of products originating from waste materials and the proof of their identity. (author)

  5. Mechanistic modelling of the vertical soil organic matter profile

    NARCIS (Netherlands)

    Braakhekke, M.C.

    2014-01-01

    Soil organic matter (SOM) constitutes a large global pool of carbon that may play a considerable role for future climate. The vertical distribution of SOM in the profile may be important due to depth-dependence of physical, chemical, and biological conditions, and links to physical processes

  6. Predicting degradability of organic chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Finizio, A; Vighi, M [Milan Univ. (Italy). Ist. di Entomologia Agraria

    1992-05-01

    Degradability, particularly biodegradability, is one of the most important factors governing the persistence of pollutants in the environment and consequently influencing their behavior and toxicity in aquatic and terrestrial ecosystems. The need for reliable persistence data in order to assess the environmental fate and hazard of chemicals by means of predictive approaches, is evident. Biodegradability tests are requested by the EEC directive on new chemicals. Neverthless, degradation tests are not easy to carry out and data on existing chemicals are very scarce. Therefore, assessing the fate of chemicals in the environment from the simple study of their structure would be a useful tool. Rates of degradation are a function of the rates of a series of processes. Correlation between degradation rates and structural parameters are will be facilitated if one of the processes is rate determining. This review is a survey of studies dealing with relationships between structure and biodegradation of organic chemicals, to identify the value and limitations of this approach.

  7. Non disturbing characterization and quantification of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electro-spray and atmospheric pressure chemical ionization modes

    International Nuclear Information System (INIS)

    Huclier-Markai, S.; Landesman, C.; Grambow, B.; Rogniaux, H.; Monteau, F.; Vinsot, A.

    2010-01-01

    Document available in extended abstract form only. The Callovo-Oxfordian formation (COx) rock may contain up to 1% w/w of organic Carbon. Most of the Organic Matter (OM) is attached to the mineral particles whereas a small portion is present as Dissolved Organic Matter (DOM) in the pore water. In environmental studies, Natural Organic Matter (NOM) plays a key role on the bioavailability and the toxicity of metallic compounds. It is necessary to know the structure of any organic substance in order to assess which chemical and biological reactions occur under environmentally relevant conditions. The 150 Myears solid-bound organic matter of the COx (kerogen) has been already investigated in several studies and originates from a mixture of marine and terrestrial sources. In addition to this, the CCl 4 soluble organic fraction (bitumen) has been already characterized by liquid and gas chromatography coupled to mass spectrometry. It allows proportion and distribution of biological markers to be determined as polar compounds with aromatic and saturated hydrocarbons. DOM was extracted from a crushed clay rock of the COx formation with a high rock/water ratio of about 1500 g/L. Part of the OM from the COx is known to be sensitive to air oxidation which can significantly modify the nature of the bitumen by an overall shift towards lower molecular weight compounds. Therefore, the characteristics of the DOM must be determined in in-situ like conditions if one wants to assess the mobility of DOM in the clay pore space and to evaluate the mobility of heavy metals/ radionuclides. Due to their high binding capacity with metal ions and their colloidal sizes in natural waters, these macromolecules, through complexation reactions, might either enhance the mobility of trace elements, or reduce their migration rates by sorption processes in relation with their size and that of the porous medium. Consequently, the characterization of DOM in anoxic pore water samples from the COx

  8. Organic carbon organic matter and bulk density relationships in arid ...

    African Journals Online (AJOL)

    Soil organic matter (SOM) and soil organic carbon (SOC) constitute usually a small portion of soil, but they are one of the most important components of ecosystems. Bulk density (dB or BD) value is necessary to convert organic carbon (OC) content per unit area. Relationships between SOM, SOC and BD were established ...

  9. Biological activity during co-composting of sludge issued from the OMW evaporation ponds with poultry manure-Physico-chemical characterization of the processed organic matter.

    Science.gov (United States)

    Hachicha, Salma; Sellami, Fatma; Cegarra, Juan; Hachicha, Ridha; Drira, Noureddine; Medhioub, Khaled; Ammar, Emna

    2009-02-15

    Olive mill sludge (OMS), a by-product resulting from natural evaporation of olive oil processing effluent, poses a major environmental threat. A current cost-effective practice of OMS management is composting. A mixture of OMS (60%) with poultry manure (PM) was successfully composted for 210 days. During the process, effluents of olive oil mill and confectionary were used to keep moisture at optimal level (40-60%). Biological indicators reflecting stability of the compost (microbial biota respiration and enumeration, and germination index) were analysed for the assessment of the product quality. The composted mixture showed a high microbial activity with a succession of microbial populations depending on the temperature reached during the biodegradation. The pathogen content from PM decreased with composting as did phytotoxic compounds. Phenols and lipids were reduced, respectively, by 40% and 84% while germination index increased with composting progress. Fourier transform infrared (FTIR) spectroscopic analysis revealed that the final compost improved the aromatic content compared to the starting materials, with a decrease in aliphatic groups and a reduction in the easily assimilated components by the microflora acting during the biological process. The final compost was characterized by relatively high organic matter content (26.21%), a low C/N ratio (16.21), an alkaline pH (8.32), a relatively high electrical conductivity (9.21mS/cm) and a high level of nutrients. The germination index for Lepidium sativum L. was 87.71% after 210 days of composting, showing that the final compost was not phytotoxic.

  10. Accuracy of two optical chlorophyll meters in predicting chemical composition and in vitro ruminal organic matter degradability of Brachiaria hybrid, Megathyrsus maximus, and Paspalum atratum

    Directory of Open Access Journals (Sweden)

    Martin P. Hughes

    2017-03-01

    Full Text Available The objective of this study was to determine the accuracy and reliability of 2 optical chlorophyll meters: FieldScout CM 1,000 NDVI and Yara N-Tester, in predicting neutral detergent fibre (NDF, acid detergent fibre (ADF, acid detergent lignin (ADL, acid detergent insoluble nitrogen (ADIN and in vitro ruminal organic matter degradability (IVOMD of 3 tropical grasses. Optical chlorophyll measurements were taken at 3 stages (4, 8 and 12 weeks of regrowth in Brachiaria hybrid, and Megathyrsus maximus and at 6 and 12 weeks of regrowth in Paspalum atratum (cv. Ubon. Optical chlorophyll measurements showed the highest correlation (r = 0.57 to 0.85 with NDF concentration. The FieldScout CM 1,000 NDVI was better than the Yara N-Tester in predicting NDF (R2 = 0.70 and ADF (R2 = 0.79 concentrations in Brachiaria hybrid and NDF (R2 = 0.79 in M. maximus. Similarly, FieldScout CM 1,000 NDVI produced better estimates of 24 h IVOMD (IVOMD24h in Brachiaria hybrid (R2 = 0.81 and IVOMD48h in Brachiaria hybrid (R2 = 0.65 and M. maximus (R2 = 0.75. However, these prediction models had relatively low concordance correlation coefficients, i.e., CCC >0.90, but random errors were the main source of bias. It was, therefore, concluded that both optical chlorophyll meters were poor and unreliable predictors of ADIN and ADL concentrations. Overall, the FieldScout CM 1,000 NDVI shows potential to produce useful estimates of IVOMD24h and ADF in Brachiaria hybrid and IVOMD48h and NDF concentrations in M. maximus.

  11. Temperature sensitivity of respiration scales with organic matter recalcitrance

    Science.gov (United States)

    Craine, J. M.; Fierer, N.; McLauchlan, K. K.

    2010-12-01

    Microbial decomposition of soil organic matter is a key process in determining the carbon sequestration potential of ecosystems and carbon fluxes to the atmosphere. Since microbial decomposition is highly sensitive to short-term changes in temperature, predicting the temperature sensitivity of microbial decomposition is critical to predicting future atmospheric carbon dioxide concentrations and feedbacks to anthropogenic warming. Fundamental principles of enzyme kinetics, embodied in the carbon-quality temperature hypothesis, predict that the temperature sensitivity of microbial decomposition should increase with increasing biochemical recalcitrance of a substrate. To test the generality of this principle, we measured the temperature sensitivity of microbial respiration of soil organic matter with serial short-term temperature manipulations over 365 days for 28 North American soils. When joined with data from similar studies that represent a wide variety of contrasts, we show that the temperature sensitivity of organic matter decomposition scales with biochemical recalcitrance. With physico-chemical protection likely an important covariate for relating plant and soil organic matter decomposition scalars, biochemically recalcitrant organic matter is highly susceptible to short-term increases in temperature, a key link in predicting the effects of warming on carbon cycling.

  12. Chemical and biological characterization of urban particulate matter

    International Nuclear Information System (INIS)

    Agurell, E.; Alsberg, T.; Assefaz-Redda, Y.

    1990-11-01

    Airborne particulate matter has been collected on glass fiber filter by high volume sampling in the Goeteborg urban area. The samples were, after extraction with respect to organic components, tested for biological effect in the Salmonella mutagenicity assay, affinity to the cytosol TCDD receptor and toxicity towards a mammalian cell system and analysed chemically for selected polycyclic aromatic compounds. A series of samples collected simultaneously at a street level location and a rooftop site showed that most parameters associated with the organic compounds adsorbed to airborne particulate matter has similar concentrations at the two levels. The differences observed for the mutagenic effect in different strains and conditions showed that the rooftop samples had a different composition compared to the street samples indicating that atmospheric transformations have occurred. Chemical fractionation of representative samples showed that the distribution of mutagenic activity among different fractions is dissimilar to the distribution obtained in the fractionation of both gasoline and diesel engine exhaust particles. Partial least squares regression analysis showed qualitatively that diesel exhaust is a major source of airborne particulate mutagenic activity and source apportionment with chemical mass balance and multilinear regression corroborated this quantitatively. The multilinear regression analysis gave the result that the airborne activity in Salmonella TA90-S9 originated to 54±4% from diesel exhaust and to 26±3% from gasoline exhaust. The contribution is more equal for the activity measured with TA98+S9. The usefulness of short-term bioassays as an addition to chemical analysis of airborne particulate matter depends on whether only polycylic aromatic hydrocarbons (PAH) are major carcinogens, as has been suggested in the literature, or whether also other polycyclic aromatic compound (PAC) are of importance. (au)

  13. Effect of organic fertilizers derived dissolved organic matter on pesticide sorption and leaching

    Energy Technology Data Exchange (ETDEWEB)

    Li Kun [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Xing Baoshan [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States) and Northeast Institute of Geography and Agro-ecology, CAS, Harbin 150040 (China)]. E-mail: bx@pssci.umass.edu; Torello, William A. [Department of Plant, Soil, and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States)

    2005-03-01

    Incorporation of organic fertilizers/amendments has been, and continues to be, a popular strategy for golf course turfgrass management. Dissolved organic matter (DOM) derived from these organic materials may, however, facilitate organic chemical movement through soils. A batch equilibrium technique was used to evaluate the effects of organic fertilizer-derived DOM on sorption of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in USGA (United States Golf Association) sand, a mixed soil (70% USGA sand and 30% native soil) and a silt loam soil (Typic Fragiochrept). DOM was extracted from two commercial organic fertilizers. Column leaching experiments were also performed using USGA sand. Sorption experiments showed that sorption capacity was significantly reduced with increasing DOM concentration in solution for all three chemicals. Column experimental results were consistent with batch equilibrium data. These results suggest that organic fertilizer-derived DOM might lead to enhanced transport of applied chemicals in turf soils. - Dissolved organic matter could result in enhanced transport of chemicals applied to turf.

  14. Effect of organic fertilizers derived dissolved organic matter on pesticide sorption and leaching

    International Nuclear Information System (INIS)

    Li Kun; Xing Baoshan; Torello, William A.

    2005-01-01

    Incorporation of organic fertilizers/amendments has been, and continues to be, a popular strategy for golf course turfgrass management. Dissolved organic matter (DOM) derived from these organic materials may, however, facilitate organic chemical movement through soils. A batch equilibrium technique was used to evaluate the effects of organic fertilizer-derived DOM on sorption of three organic chemicals (2,4-D, naphthalene and chlorpyrifos) in USGA (United States Golf Association) sand, a mixed soil (70% USGA sand and 30% native soil) and a silt loam soil (Typic Fragiochrept). DOM was extracted from two commercial organic fertilizers. Column leaching experiments were also performed using USGA sand. Sorption experiments showed that sorption capacity was significantly reduced with increasing DOM concentration in solution for all three chemicals. Column experimental results were consistent with batch equilibrium data. These results suggest that organic fertilizer-derived DOM might lead to enhanced transport of applied chemicals in turf soils. - Dissolved organic matter could result in enhanced transport of chemicals applied to turf

  15. Physico-Chemical Properties of Kaolin-Organic Acid

    Directory of Open Access Journals (Sweden)

    Yeo S.W.

    2017-01-01

    Full Text Available Soil with more than 20% of organic content is classified as organic soil in Malaysia. Contents of organic soil consist of different types of organic and inorganic matter. Each type of organic matter has its own characteristic and its effect on the properties of the soil is different. Hence, a good understanding on the effect of specific organic and inorganic matter on the physico-chemical characteristic of organic soils can serve as a guide for predicting the properties of organic soils. The main objective is to unveil the effect of organic acid on the physico-chemical properties of soil. Artificial organic soil (kaolin mixed with organic acid was utilized in order to minimize the geochemical variability of studied soil. The organic acid which consists of humic acid and fulvic acid was extracted from highly humificated plant–based compost. The effect of organic acid on the physico-chemical properties of soil was determined by varying the concentration of organic acid. The specific gravity, Atterberg limits, pH, bulk chemical composition and the functional group of kaolin-organic acid were determined. It was found that the plasticity index, specific gravity and pH value were decreased with lowered concentration of organic acid. However, the liquid limits and plastic limits were found to be increased with the concentration decrement of organic acid. The analysis of XRF on the bulk chemical composition and analysis of FTIR spectra on the functional group of artificial organic soils with different concentration have confirmed little geochemical variability between samples.

  16. Can Biochar Protect Labile Organic Matter Against Mineralization in Soil?

    Institute of Scientific and Technical Information of China (English)

    Giovanna B.MELAS; Oriol ORTIZ; Josep M.ALACA(N)IZ

    2017-01-01

    Biochar could help to stabilize soil organic (SOM) matter,thus sequestering carbon (C) into the soil.The aim of this work was to determine an easy method i) to estimate the effects of the addition of biochar and nutrients on the organic matter (SOM)mineralization in an artificial soil,proposed by the Organization for Economic Co-operation and Development (OECD),amended with glucose and ii) to measure the amount of labile organic matter (glucose) that can be sorbed and thus be partially protected in the same soil,amended or not amended with biochar.A factorial experiment was designed to check the effects of three single factors (biochar,nutrients,and glucose) and their interactions on whole SOM mineralization.Soil samples were inoculated with a microbial inoculum and preincubated to ensure that their biological activities were not limited by a small amount of microbial biomass,and then they were incubated in the dark at 21 ℃ for 619 d.Periodical measurements of C mineralized to carbon dioxide (CO2) were carried out throughout the 619-d incubation to allow the mineralization of both active and slow organic matter pools.The amount of sorbed glucose was calculated as the difference between the total and remaining amounts of glucose added in a soil extract.Two different models,the Freundlich and Langmuir models,were selected to assess the equilibrium isotherms of glucose sorption.The CO2-C release strongly depended on the presence of nutrients only when no biochar was added to the soil.The mineralization of organic matter in the soil amended with both biochar and glucose was equal to the sum of the mineralization of the two C sources separately.Furthermore,a significant amount of glucose can be sorbed on the biochar-amended soil,suggesting the involvement of physico-chemical mechanisms in labile organic matter protection.

  17. Soil architecture and distribution of organic matter

    NARCIS (Netherlands)

    Kooistra, M.J.; Noordwijk, van M.

    1996-01-01

    The biological component of soil structure varies greatly in quality and quantity, occurs on different scales, and varies throughout the year. It is far less predictable than the physical part and human impact. The occurrence and distribution of organic matter depends on several processes, related

  18. Organic matter loading affects lodgepole pine seedling growth.

    Science.gov (United States)

    Wei, Xiaohua; Li, Qinglin; Waterhouse, M J; Armleder, H M

    2012-06-01

    Organic matter plays important roles in returning nutrients to the soil, maintaining forest productivity and creating habitats in forest ecosystems. Forest biomass is in increasing demand for energy production, and organic matter has been considered as a potential supply. Thus, an important management question is how much organic matter should be retained after forest harvesting to maintain forest productivity. To address this question, an experimental trial was established in 1996 to evaluate the responses of lodgepole pine seedling growth to organic matter loading treatments. Four organic matter loading treatments were randomly assigned to each of four homogeneous pine sites: removal of all organic matter on the forest floor, organic matter loading quantity similar to whole-tree-harvesting residuals left on site, organic matter loading quantity similar to stem-only-harvesting residuals, and organic matter loading quantity more similar to what would be found in disease- or insect-killed stands. Our 10-year data showed that height and diameter had 29 and 35 % increase, respectively, comparing the treatment with the most organic matter loading to the treatment with the least organic matter loading. The positive response of seedling growth to organic matter loading may be associated with nutrients and/or microclimate change caused by organic matter, and requires further study. The dynamic response of seedling growth to organic matter loading treatments highlights the importance of long-term studies. Implications of those results on organic matter management are discussed in the context of forest productivity sustainability.

  19. Chemical Composition of Fine Particulate Matter and Life Expectancy

    Science.gov (United States)

    Dominici, Francesca; Wang, Yun; Correia, Andrew W.; Ezzati, Majid; Pope, C. Arden; Dockery, Douglas W.

    2016-01-01

    Background In a previous study, we provided evidence that a decline in fine particulate matter (PM2.5) air pollution during the period between 2000 and 2007 was associated with increased life expectancy in 545 counties in the United States. In this article, we investigated which chemical constituents of PM2.5 were the main drivers of the observed association. Methods We estimated associations between temporal changes in seven major components of PM2.5 (ammonium, sulfate, nitrate, elemental carbon matter, organic carbon matter, sodium, and silicon) and temporal changes in life expectancy in 95 counties between 2002 and 2007. We included US counties that had adequate chemical components of PM2.5 mass data across all seasons. We fitted single pollutant and multiple pollutant linear models, controlling for available socioeconomic, demographic, and smoking variables and stratifying by urban and nonurban counties. Results In multiple pollutant models, we found that: (1) a reduction in sulfate was associated with an increase in life expectancy; and (2) reductions in ammonium and sodium ion were associated with increases in life expectancy in nonurban counties only. Conclusions Our findings suggest that recent reductions in long-term exposure to sulfate, ammonium, and sodium ion between 2002 and 2007 are associated with improved public health. PMID:25906366

  20. Lability of Secondary Organic Particulate Matter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; Giles, Mary K.; Zaveri, Rahul A.; Bertram, Allan K.; Martin, Scot T.

    2016-10-24

    Accurate simulations of the consenctrations of atmospheric organic particulate matter (PM) are needed for predicting energy flow in the Earth’s climate system. In the past, simulations of organic PM widely assume equilibrium partitioning of semivolatile organic compounds (SVOCs) between the PM and surrounding vapor. Herein, we test this assumption by measuring evaporation rates and associated vapor mass concentration of organic films representative of atmospheric PM. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH), indicating equilibrium partitioning above a transition RH but not below. In contrast for films representing biogenic PM, no threshold was observed, indicating equilibrium partitioning at all RHs. The results suggest that the mass lability of atmospheric organic PM can differ in consequential ways among Earth’s natural biomes, polluted regions, and regions of land-use change, and these differences need to be considered when simulating atmospheric organic PM.

  1. Microwaves in organic chemistry and organic chemical

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2005-01-01

    Full Text Available The usual way of applying heat to a chemical reaction is the use of a Bunsen burner, an oil or some other type of bath, or an electric heater. In inorganic chemistry, microwave technology has been used since the late 1970s while it has been implemented in organic chemistry since the mid-1980s. Microwave heating has been used in the food industry for almost fifty years. The shorter reaction times and expanded reaction range that is offered by microwave technology are suited to the increased demands in industry. For example, there is a requirement in the pharmaceutical industry for a higher number of a novel chemical entities to be produced, which requires chemists to employ a number of resources to reduce time for the production of compounds. Also, microwaves are used in the food industry, as well as in the pyrolysis of waste materials, sample preparation, the solvent extraction of natural products and the hydrolysis of proteins and peptides.

  2. Sorption of polycyclic aromatic hydrocarbons on particulate organic matters

    International Nuclear Information System (INIS)

    Guo Xueyan; Luo Lei; Ma Yibing; Zhang Shuzhen

    2010-01-01

    Particulate organic matter (POM) is a key organic matter fraction which can influence soil fertility. Its interactions with hydrophobic organic pollutants (HOCs) have not been characterized and the mechanisms of retention of HOCs by POM remain unclear. In the present study, sorption behaviors of polycyclic aromatic hydrocarbons (PAHs) naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) by POMs separated from different soils were examined and the POMs were characterized by elemental analysis, solid state 13 C NMR, and Fourier transform infrared spectroscopy (FT-IR). The results indicated that POMs were mainly composed of aliphatic components with high polarity. The different original POMs showed similar chemical composition and configuration. Sorption behaviors of PAHs indicated that there was no significant difference in sorption capacity among the POMs. Sorption of NAP and PHE by POMs displayed a nonlinear isotherm, while sorption of PYR yielded a linear isotherm. No significant hysteresis and ionic strength effect were observed for PAH desorption from the POMs.

  3. A linear solvation energy relationship model of organic chemical partitioning to dissolved organic carbon.

    Science.gov (United States)

    Kipka, Undine; Di Toro, Dominic M

    2011-09-01

    Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in environmental risk assessment. To date, the association of a contaminant to particulate organic matter is considered in many multimedia transport models, but the effect of dissolved organic matter is typically ignored due to a lack of either reliable models or experimental data. The partition coefficient to dissolved organic carbon (K(DOC)) may be used to estimate the fraction of a contaminant that is associated with dissolved organic matter. Models relating K(DOC) to the octanol-water partition coefficient (K(OW)) have not been successful for many types of dissolved organic carbon in the environment. Instead, linear solvation energy relationships are proposed to model the association of chemicals with dissolved organic matter. However, more chemically diverse K(DOC) data are needed to produce a more robust model. For humic acid dissolved organic carbon, the linear solvation energy relationship predicts log K(DOC) with a root mean square error of 0.43. Copyright © 2011 SETAC.

  4. Age heterogeneity of soil organic matter

    International Nuclear Information System (INIS)

    Rethemeyer, J.; Grootes, P.M.; Bruhn, F.; Andersen, N.; Nadeau, M.J.; Kramer, C.; Gleixner, G.

    2004-01-01

    Accelerator mass spectrometry (AMS) radiocarbon measurements were used to investigate the heterogeneity of organic matter in soils of agricultural long-term trial sites in Germany and Great Britain. The strong age heterogeneity of the soil organic matter (SOM) is reflected by highly variable 14 C values of different organic components, ranging from modern (>100 pMC) to 7% modern carbon (pMC). At the field experiment in Halle (Germany), located in a heavily industrialized area, an increase of 14 C content with increasing depth was observed even though the input of modern plant debris should be highest in the topsoil. This is attributed to a significant contribution of old carbon (of up to 50% in the topsoil) to SOM. As a test to exclude the old carbon contamination, more specific SOM fractions were extracted. However, even a phospholipid fraction representing viable microbial biomass that is supposed to be short-lived in SOM, shows a strong influence of old, refractory carbon, when radiocarbon dated. In contrast, 14 C data of other field trials distant from industrial areas indicate that there inputs of old carbon to the soil are lower or even absent. Such locations are more favorable to study SOM stabilization and to quantify turnover of organic carbon in soils

  5. Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    Arndt Schimmelmann; Maria Mastalerz

    2010-03-30

    Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.

  6. Organic chemicals in the environment

    International Nuclear Information System (INIS)

    Anderson, T.A.; Beauchamp, J.J.; Walton, B.T.

    1991-01-01

    Disappearance of 15 volatile and semivolatile organic compounds was determined in a mixture added to two different soil types using experimental procedures to distinguish abiotic losses from biological degradation over a 7-d period. Losses due to volatilization were quantified and mass balances were calculated for each compound. The compounds (methyl ethyl ketone; tetrahydrofuran; chlorobenzene; benzene; chloroform; carbon tetrachloride; p-xylene; 1,2-dichlorobenzene; cis-1,4-dich-loro-2-butene; 1,2,3-trichloropropane; 2-chloronaphthalene; ethylene dibromide; hexachlorobenzene; nitrobenzene; and toluene) were applied to the soil in a mixture such that the concentration of each chemical was 100 mg/kg soil (dry wt.). Apparent half-lives for the 15 organic compounds ranged from 14 C-toluene, were unsuccessful. Nonreversible sorption and preanalysis storage conditions were considered as contributors to this inability to achieve a mass balance. On the basis of these results, the authors strongly advise positive accounting for all test compounds and degradation products at the conclusion of studies involving volatile and semivolatile compounds

  7. Clay-associated organic matter in kaolinitic and smectitic soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.

    2002-01-01

    The primary source of soil organic matter is plant debris of all kinds, such as dead roots, leaves and branches that enter into the soil and are then biologically decomposed at variable rates. Organic matter has many different important functions on a local and global scale. Soil organic matter is

  8. Repeated application of organic waste affects soil organic matter composition

    DEFF Research Database (Denmark)

    Peltre, Clément; Gregorich, Edward G.; Bruun, Sander

    2017-01-01

    Land application of organic waste is an important alternative to landfilling and incineration because it helps restore soil fertility and has environmental and agronomic benefits. These benefits may be related to the biochemical composition of the waste, which can result in the accumulation...... of different types of carbon compounds in soil. The objective of this study was to identify and characterise changes in soil organic matter (SOM) composition after repeated applications of organic waste. Soil from the CRUCIAL field experiment in Denmark was sampled after 12 years of annual application...... that there was accumulation in soil of different C compounds for the different types of applied organic waste, which appeared to be related to the degree to which microbial activity was stimulated and the type of microbial communities applied with the wastes or associated with the decomposition of applied wastes...

  9. Lead sequestration and species redistribution during soil organic matter decomposition

    Science.gov (United States)

    Schroth, A.W.; Bostick, B.C.; Kaste, J.M.; Friedland, A.J.

    2008-01-01

    The turnover of soil organic matter (SOM) maintains a dynamic chemical environment in the forest floor that can impact metal speciation on relatively short timescales. Here we measure the speciation of Pb in controlled and natural organic (O) soil horizons to quantify changes in metal partitioning during SOM decomposition in different forest litters. We provide a link between the sequestration of pollutant Pb in O-horizons, estimated by forest floor Pb inventories, and speciation using synchrotron-based X-ray fluorescence and X-ray absorption spectroscopy. When Pb was introduced to fresh forest Oi samples, it adsorbed primarily to SOM surfaces, but as decomposition progressed over two years in controlled experiments, up to 60% of the Pb was redistributed to pedogenic birnessite and ferrihydrite surfaces. In addition, a significant fraction of pollutant Pb in natural soil profiles was associated with similar mineral phases (???20-35%) and SOM (???65-80%). Conifer forests have at least 2-fold higher Pb burdens in the forest floor relative to deciduous forests due to more efficient atmospheric scavenging and slower organic matter turnover. We demonstrate that pedogenic minerals play an important role in surface soil Pb sequestration, particularly in deciduous forests, and should be considered in any assessment of pollutant Pb mobility. ?? 2008 American Chemical Society.

  10. Micro-Scale Characteristics of Insoluble Organic Matter in Chondrites: A Coordinated TEM, STXM and SIMS Study

    Science.gov (United States)

    Nittler, L. R.; Alexander, C. M. O'd.; Cody, G. D.; de Gregorio, B. T.; Kilcoyne, A. L. D.; Stroud, R. M.; Tiwari, A.

    2009-03-01

    A coordinated study of meteoritic insoluble organic matter reveals that hollow organic globules are chemically similar to other IOM, but abundances and sizes of globules vary between meteorites. IOM is sensitive to electron and X-ray induced beam damage.

  11. Compound-specific C- and H-isotope compositions of enclosed organic matter in carbonate rocks: Implications for source identification of sedimentary organic matter and paleoenvironmental reconstruction

    International Nuclear Information System (INIS)

    Xiong Yongqiang; Wang Yanmei; Wang Yongquan; Xu Shiping

    2007-01-01

    The Bohai Bay Basin is one of the most important oil-producing provinces in China. Molecular organic geochemical characteristics of Lower Paleozoic source rocks in this area have been investigated by analyzing chemical and isotopic compositions of solvent extracts and acid-released organic matter from the Lower Paleozoic carbonate rocks in the Jiyang Sub-basin of the Bohai Bay Basin. The results indicate that enclosed organic matter in carbonate rocks has not been recognizably altered by post-depositional processes. Two end-member compositions are suggested for early organic matter trapped in the Lower Paleozoic carbonate rocks: (1) a source dominated by aquatic organisms and deposited in a relatively deep marine environment and (2) a relatively high saline, evaporative marine depositional environment. In contrast, chemical and isotopic compositions of solvent extracts from these Lower Paleozoic carbonate rocks are relatively complicated, not only inheriting original characteristics of their precursors, but also overprinted by various post-depositional alterations, such as thermal maturation, biodegradation and mixing. Therefore, the integration of both organic matter characteristics can provide more useful information on the origin of organic matter present in carbonate rocks and the environments of their deposition

  12. Compound-specific C- and H-isotope compositions of enclosed organic matter in carbonate rocks: Implications for source identification of sedimentary organic matter and paleoenvironmental reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Xiong Yongqiang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)], E-mail: xiongyq@gig.ac.cn; Wang Yanmei; Wang Yongquan; Xu Shiping [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2007-11-15

    The Bohai Bay Basin is one of the most important oil-producing provinces in China. Molecular organic geochemical characteristics of Lower Paleozoic source rocks in this area have been investigated by analyzing chemical and isotopic compositions of solvent extracts and acid-released organic matter from the Lower Paleozoic carbonate rocks in the Jiyang Sub-basin of the Bohai Bay Basin. The results indicate that enclosed organic matter in carbonate rocks has not been recognizably altered by post-depositional processes. Two end-member compositions are suggested for early organic matter trapped in the Lower Paleozoic carbonate rocks: (1) a source dominated by aquatic organisms and deposited in a relatively deep marine environment and (2) a relatively high saline, evaporative marine depositional environment. In contrast, chemical and isotopic compositions of solvent extracts from these Lower Paleozoic carbonate rocks are relatively complicated, not only inheriting original characteristics of their precursors, but also overprinted by various post-depositional alterations, such as thermal maturation, biodegradation and mixing. Therefore, the integration of both organic matter characteristics can provide more useful information on the origin of organic matter present in carbonate rocks and the environments of their deposition.

  13. A new method for identifying the types of organic matter

    International Nuclear Information System (INIS)

    Tong Chunhan; Li Guodong

    1991-01-01

    A new method for dividing the types of organic matter according to V and Ni contents in soluble organic matter determined by NAA is introduced. The research site was an oil-gas field in northeastern China. The type of organic matter is an important parameter in evaluating an oil or a gas field. The conventional organic geochemistry methods will meet unsurmountable difficulties when the maturity of organic matter is high. The method described in this paper can solve the problem. (author) 4 refs.; 1 fig.; 2 tabs

  14. Interactions of diuron with dissolved organic matter from organic amendments.

    Science.gov (United States)

    Thevenot, Mathieu; Dousset, Sylvie; Hertkorn, Norbert; Schmitt-Kopplin, Philippe; Andreux, Francis

    2009-07-01

    Diuron is frequently detected in some drinking water reservoirs under the Burgundy vineyards, where organic amendments are applied. The environmental effect of these amendments on pesticide transport is ambiguous: on the one hand it could enhance their retention by increasing soil organic carbon content; on the other hand, dissolved organic matter (DOM) could facilitate their transport. Elutions were performed using columns packed with glass beads in order to investigate DOM-diuron interactions, and the possible co-transport of diuron and DOM. Four organic amendments (A, B, C and D) were tested; C and D were sampled at fresh (F) and mature (M) stages. An increase in diuron leaching was observed only for A and D(F) amendments (up to 16% compared to the DOM-free blank samples), suggesting a DOM effect on diuron transport. These results could be explained by the higher DOM leaching for A and D(F) compared to B, C(F), C(M) and D(M) increasing diuron-DOM interactions. These interactions seem to be related to the aromatic and aliphatic content of the DOM, determining formation of hydrogen and non-covalent bonds. The degree of organic matter maturity does not seem to have any effect with amendment C, while a reduction in diuron leaching is observed between D(F) and D(M). After equilibrium dialysis measurement of diuron-DOM complexes, it appeared that less than 3% of the diuron applied corresponded to complexes with a molecular weight >1000 Da. Complexes <1000 Da could also take part in this facilitated transport.

  15. Calculation of baryon chemical potential and strangeness chemical potential in resonance matter

    International Nuclear Information System (INIS)

    Fu Yuanyong; Hu Shouyang; Lu Zhongdao

    2006-01-01

    Based on the high energy heavy-ion collisions statistical model, the baryon chemical potential and strangeness chemical potential are calculated for resonance matter with net baryon density and net strangeness density under given temperature. Furthermore, the relationship between net baryon density, net strangeness density and baryon chemical potential, strangeness chemical potential are analyzed. The results show that baryon chemical potential and strangeness chemical potential increase with net baryon density and net strangeness density increasing, the change of net baryon density affects baryon chemical potential and strangeness chemical potential more strongly than the change of net strangeness density. (authors)

  16. Use of carbon-14 in soil organic matter studies

    International Nuclear Information System (INIS)

    Vimal, O.P.; Kamath, M.B.

    1974-01-01

    Despite a great deal of research work on various aspects of soil organic matter, there are many gaps in the knowledge of the process of humus formation. These limitations arise mainly from the complex and heterogenous nature of soil humus substances, analytical problems in separating the fresh and decomposable materials from the old stabilized true humus substances and the lack of a clear understanding of the chemical structure of the humic acid molecule. During recent years, the use of carbon-14 has helped to trace within soil, transformation of a number of metabolites upto the point where they turn into humus. These studies have changed the concepts of the formation and stability of soil humus substances, their colloidal chemical properties and the uptake of organomolecules by plant roots. The present paper presents a synoptic view of the use of radiocarbon in studying the kinetics of humification, nature of precursors in humic acid formation, turnover of soil organic matter and the direct effects of humus substances on plant growth. (author)

  17. Nitrogen and carbon isotopes in soil with special reference to the diagnosis of organic matter

    International Nuclear Information System (INIS)

    Wada, Eitaro; Nakamura, Koichi.

    1980-01-01

    Distributions of nitrogen and carbon isotopes in terrestrial ecosystems are described based on available data and our recent findings for soil organic matters. Major processes regulating N-isotope and C-isotope ratios in biogenic substances are discussed. The biological di-nitrogen fixation and the precipitation are major sources which lower the delta 15 N value for forested soil organic matters. Denitrification enhances delta 15 N value for soil in cultivated fields. An addition of chemical fertilizer lowers 15 N content in soils. The permiation of soil water is an important factor controlling vertical profiles of delta 15 N in soil systems. Among soil organic matters, non-hydrolizable fraction seems to give unique low delta 15 N value, suggesting the utility of delta 15 N analysis in studying the nature of the fractions. delta 13 C of soil organic matter is significantly lower than that for marine sediments. delta 13 C for soil humus varies with respect to chemical forms as well as an age of soil organic matters. The variation is large in paddy fields. It is, thus, probable that delta 13 C is an useful parameter in studying the early epidiagenesis of soil organic matters. Based on the known delta 15 N-delta 13 C relationships, a two-source mixing model has been applied to assess sources of organic matters in coastal sediment. (author)

  18. In Situ Mapping of the Organic Matter in Carbonaceous Chondrites and Mineral Relationships

    Science.gov (United States)

    Clemett, Simon J.; Messenger, S.; Thomas-Keprta, K. L.; Ross, D. K.

    2012-01-01

    Carbonaceous chondrite organic matter represents a fossil record of reactions that occurred in a range of physically, spatially and temporally distinct environments, from the interstellar medium to asteroid parent bodies. While bulk chemical analysis has provided a detailed view of the nature and diversity of this organic matter, almost nothing is known about its spatial distribution and mineralogical relationships. Such information is nevertheless critical to deciphering its formation processes and evolutionary history.

  19. Analytic study of organic matters in Lodeve uranium ore

    International Nuclear Information System (INIS)

    Campuzano, E.J.

    1981-01-01

    Exploitation of uranium in the Permian basin of Lodeve is difficult because of simultaneous extraction of organic matters which are found, in small proportion, in ammonium diuranate and a supplementary purification is required. Available information on natural organic matters are briefly reviewed. Natural organic matters contained in the Lodeve uranium ore processing fluid is separated and fractionated. Physicochemical properties of ligands in each fraction are studied. The existence of bonds between these ligands and dissolved uranium is experimentally demonstrated [fr

  20. Organic speciation of size-segregated atmospheric particulate matter

    Science.gov (United States)

    Tremblay, Raphael

    Particle size and composition are key factors controlling the impacts of particulate matter (PM) on human health and the environment. A comprehensive method to characterize size-segregated PM organic content was developed, and evaluated during two field campaigns. Size-segregated particles were collected using a cascade impactor (Micro-Orifice Uniform Deposit Impactor) and a PM2.5 large volume sampler. A series of alkanes and polycyclic aromatic hydrocarbons (PAHs) were solvent extracted and quantified using a gas chromatograph coupled with a mass spectrometer (GC/MS). Large volume injections were performed using a programmable temperature vaporization (PTV) inlet to lower detection limits. The developed analysis method was evaluated during the 2001 and 2002 Intercomparison Exercise Program on Organic Contaminants in PM2.5 Air Particulate Matter led by the US National Institute of Standards and Technology (NIST). Ambient samples were collected in May 2002 as part of the Tampa Bay Regional Atmospheric Chemistry Experiment (BRACE) in Florida, USA and in July and August 2004 as part of the New England Air Quality Study - Intercontinental Transport and Chemical Transformation (NEAQS - ITCT) in New Hampshire, USA. Morphology of the collected particles was studied using scanning electron microscopy (SEM). Smaller particles (one micrometer or less) appeared to consist of solid cores surrounded by a liquid layer which is consistent with combustion particles and also possibly with particles formed and/or coated by secondary material like sulfate, nitrate and secondary organic aerosols. Source apportionment studies demonstrated the importance of stationary sources on the organic particulate matter observed at these two rural sites. Coal burning and biomass burning were found to be responsible for a large part of the observed PAHs during the field campaigns. Most of the measured PAHs were concentrated in particles smaller than one micrometer and linked to combustion sources

  1. Organic matter dynamics and N mineralization in grassland soils

    OpenAIRE

    Hassink, J.

    1995-01-01


    The aims of this study are i) to improve our understanding of the interactions between soil texturelsoil structure, soil organic matter, soil biota and mineralization in grassland soils, ii) to develop a procedure that yields soil organic matter fractions that can be determined directly and can be used in soil organic matter models, iii) to develop a model that predicts the long-term dynamics of soil organic matter, iv) to develop a simple model that can be used by farmers and advi...

  2. Thallium and Silver binding to dissolved organic matter

    Science.gov (United States)

    Benedetti, M. F.; Martin, L.; Simonucci, C.; Viollier, E.

    2017-12-01

    Silver (Ag) and thallium (Tl) are potential contaminants at the vicinity of mining sites and are harmful pollutants. Silver can be found in mine but also as released by the dissolution of Silver nanoparticles, a major new emerging contaminant. Tl is both lithophilic and calcophilic elements and found in sulphur ores (associated with lead, zinc, antimony…) or in rocks containing K-feldspar. Speciation of Ag and Tl is poorly known mainly due to their low concentrations in aquatic environments. Review of Ag and Tl geochemistry clearly shows a lack of quantitative information about interactions with natural organic matter. Organic ligands could play an important role in Ag or Tl bioavailability, chemical reactivity (adsorption or photo oxidation inhibition or catalysis) and hence geochemical transfers. Based on equilibrium between two solutions that are separated by a selectively permeable membrane, the so-called "Donnan membrane technique" (DMT) provides a measure of free ion concentrations. Analytes measurements are performed by HR-ICP-MS Element 2 (Thermo Scientific). Experimental setup allows the Donnan equilibrium to be reached after 100 and 120 hours for Tl. Experiments performed with purified natural organic matter allow calculating complexation constants in multiple pH conditions. With this work, we contribute new data and interpretations to an active debate on Ag and Tl geochemical modeling. In conclusion, this work brings a new view on risk assessment for mining activities.

  3. Photobiogeochemistry of organic matter. Principles and practices in water environments

    Energy Technology Data Exchange (ETDEWEB)

    Mostofa, Khan M.G. [Chinese Academy of Sciences, Guiyang, Guizhou (China). Inst. of Geochemistry; Yoshioka, Takahito [Kyoto Univ. (Japan). Field Science Education; Mottaleb, M. Abdul [Northwest Missouri State Univ., MO (United States). Dept. of Chemistry and Physics; Vione, Davide (eds.) [Turin Univ. (Italy). Dipt. di Chimica Analitica

    2013-03-01

    Gives a comprehensive account of photo and biological processes of key biogeochemical functions and their interrelations in the aquatic environment. Discusses essential issues refering to the aquatic environment. Designed as a study text for students. Photoinduced processes, caused by natural sunlight, are key functions for sustaining all living organisms through production and transformation of organic matter (OM) in the biosphere. Production of hydrogen peroxide (H2O2) from OM is a primary step of photoinduced processes, because H2O2 acts as strong reductant and oxidant. It is potentially important in many aquatic reactions, also in association with photosynthesis. Allochthonous and autochthonous dissolved organic matter (DOM) can be involved into several photoinduced or biological processes. DOM subsequently undergoes several physical, chemical, photoinduced and biological processes, which can be affected by global warming. This book is uniquely structured to overview some vital issues, such as: DOM; H2O2 and ROOH; HO x; Degradation of DOM; CDOM, FDOM; Photosynthesis; Chlorophyll; Metal complexation, and Global warming, as well as their mutual interrelationships, based on updated scientific results''.

  4. Complexation of lead by organic matter in Luanda Bay, Angola.

    Science.gov (United States)

    Leitão, Anabela; Santos, Ana Maria; Boaventura, Rui A R

    2015-10-01

    Speciation is defined as the distribution of an element among different chemical species. Although the relation between speciation and bioavailability is complex, the metal present as free hydrated ion, or as weak complexes able to dissociate, is usually more bioavailable than the metal incorporated in strong complexes or adsorbed on colloidal or particulate matter. Among the analytical techniques currently available, anodic stripping voltammetry (ASV) has been one of the most used in the identification and quantification of several heavy metal species in aquatic systems. This work concerns the speciation study of lead, in original (natural, non-filtered) and filtered water samples and in suspensions of particulate matter and sediments from Luanda Bay (Angola). Complexes of lead with organics were identified and quantified by differential pulse anodic stripping voltammetry technique. Each sample was progressively titrated with a Pb(II) standard solution until complete saturation of the organic ligands. After each addition of Pb(II), the intensity, potential and peak width of the voltammetric signal were measured. The results obtained in this work show that more than 95 % of the lead in the aquatic environment is bound in inert organic complexes, considering all samples from different sampling sites. In sediment samples, the lead is totally (100 %) complexed with ligands adsorbed on the particles surface. Two kinds of dominant lead complexes, very strong (logK >11) and strong to moderately strong (8< logK <11), were found, revealing the lead affinity for the stronger ligands.

  5. Origin and fate of organic matter in sandy soils along a primary vegetation succession

    NARCIS (Netherlands)

    Nierop, K.

    1999-01-01

    Until now little is known about the role vegetation plays in the organic matter formation, particularly at the molecular level. Most ecosystems have a long history, which is unknown or too complex to find distinct relations between vegetation and the chemical composition of soil organic

  6. Carbon and nitrogen molecular composition of soil organic matter fractions resistant to oxidation

    Science.gov (United States)

    Katherine Heckman; Dorisel Torres; Christopher Swanston; Johannes Lehmann

    2017-01-01

    The methods used to isolate and characterise pyrogenic organic carbon (PyC) from soils vary widely, and there is little agreement in the literature as to which method truly isolates the most chemically recalcitrant (inferred from oxidative resistance) and persistent (inferred from radiocarbon abundance) fraction of soil organic matter. In addition, the roles of fire,...

  7. Transuranium elements in organic chemical forms

    International Nuclear Information System (INIS)

    Sakanoue, Masanobu; Yamamoto, Masayoshi

    1987-01-01

    It is very important to achive an understanding what role organic matter plays in the behavior of transuranium elements in the environment. This paper reports the studies on characteristics of fallout Pu and Am in soil closely related to soil organic matter, and interaction of humic acid and Am (III) in aqueous solution. From the results obtained, it was suggested that the humic acids had strong interaction with transuranium elements, but such soluble complexes were removed soon from the solution by coagulation and sorption on soil. (author)

  8. Organic Matter Quality and Partitioning of Polychlorinated Biphenyls

    National Research Council Canada - National Science Library

    Brannon, James

    1997-01-01

    ...). Equilibrium partitioning of neutral organic chemicals between the organic carbon fraction of bedded sediments and the interstitial water of the sediments provides the theoretical basis for the most...

  9. Changes in River Organic Matter Through Time.

    Science.gov (United States)

    Hudson, N.; Baker, A.; Ward, D.

    2006-12-01

    Samples of river water from central England were collected during the summer base-flow period. They were analysed for BOD and filtered at 1.2μm and 0.1μm increments to obtain i) the colloidal and dissolved, and ii) dissolved filter sterilized fractions. Each filtered fraction was plated up for microbiological cell counts and the agar plates and water samples were stored under a range of environmental conditions (4° C dark, 11° C light/ dark, 11° C dark, and 20° C dark) for 26 days. Absorbance, fluorescence, pH, conductivity and total organic carbon (TOC) were measured and colony forming units (CFU) counted on days 1, 2, 3, 4, 5, 12, 19 and 26. The fluorescence intensity was recorded for 5 commonly studied regions: protein like fluorescence, indicative of microbial activity, represented by the fluorescent amino acids tyrosine and tryptophan (which has two clear fluorescence regions) and humic and fulvic acids derived from the break down of terrestrial and aquatic plant material. Humic and fulvic-like fluorescence increased in all samples under all storage conditions suggesting that peaks A and C probably include a microbial element, either a product of the living community or as dead cell material in all fraction sizes including bacterial activity associated with algal growth. It may also occur as a result of changing water chemistry causing a change in molecular conformation, and resulting fluorescence, as an increase in pH was also observed in these samples. This work illustrates the dynamic character of river organic matter within a timescale and under conditions that are representative of the natural system.

  10. Natural organic matters removal efficiency by coagulation

    Science.gov (United States)

    Sapingi, Mohd Sharizal Mohd; Pishal, Munirah; Murshed, Mohamad Fared

    2017-10-01

    The presence of Natural Organic Matter (NOM) in surface water results in unwanted characteristics in terms of color, odor, and taste. NOM content reaction with free chlorine in treated water lowers the water quality further. Chlorine is added for disinfection and produces undesirable disinfection by-products (DPBs). DBPs in drinking water are carcinogenic to consumers and may promote cancerous cell development in the human body. This study was performed to compare the coagulant efficiency of aluminum sulfate (Alum) and ferric chloride (FeCl3) on NOM removal (as in UV254 absorbance) and turbidity removal under three pH conditions (pH 6, pH 7, and sample actual pH). The three sampling points for these studies were Jalan Baru River, Kerian River, and Redac Pond. Additional sampling points, such as Lubuk Buntar and a tubewell located in the Civil Engineering School, were included to observe differences in characteristics. DOC, UV absorbance, and full wavelength were tested, after which samples treated with alum were also tested to further analyze the NOM content. Based on UV254 absorbance and DOC data, specific UV value was calculated to obtain vital synopsis of the characteristics of NOM content, as well as coagulation efficiency.

  11. The evolution of organic matter in space.

    Science.gov (United States)

    Ehrenfreund, Pascale; Spaans, Marco; Holm, Nils G

    2011-02-13

    Carbon, and molecules made from it, have already been observed in the early Universe. During cosmic time, many galaxies undergo intense periods of star formation, during which heavy elements like carbon, oxygen, nitrogen, silicon and iron are produced. Also, many complex molecules, from carbon monoxide to polycyclic aromatic hydrocarbons, are detected in these systems, like they are for our own Galaxy. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly high number of molecules that are used in contemporary biochemistry on the Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites and interplanetary dust particles. Large quantities of extra-terrestrial material were delivered via comets and asteroids to young planetary surfaces during the heavy bombardment phase. Monitoring the formation and evolution of organic matter in space is crucial in order to determine the prebiotic reservoirs available to the early Earth. It is equally important to reveal abiotic routes to prebiotic molecules in the Earth environments. Materials from both carbon sources (extra-terrestrial and endogenous) may have contributed to biochemical pathways on the Earth leading to life's origin. The research avenues discussed also guide us to extend our knowledge to other habitable worlds.

  12. The Relationship Between Dissolved Organic Matter Composition and Organic Matter Optical Properties in Freshwaters

    Science.gov (United States)

    Aiken, G.; Spencer, R. G.; Butler, K.

    2010-12-01

    Dissolved organic matter (DOM) chemistry and flux are potentially useful, albeit, underutilized, indicators of watershed characteristics, climate influences on watershed hydrology and soils, and changes associated with resource management. Source materials, watershed geochemistry, oxidative processes and hydrology exert strong influences on the nature and reactivity of DOM in aquatic systems. The molecules that comprise DOM, in turn, control a number of environmental processes important for ecosystem function including light penetration and photochemistry, microbial activity, mineral dissolution/precipitation, and the transport and reactivity of hydrophobic compounds and metals (e.g. Hg). In particular, aromatic molecules derived from higher plants exert strong controls on aquatic photochemistry, and on the transport and biogeochemistry of metals. Assessment of DOM composition and transport, therefore, can provide a basis for understanding watershed processes and biogeochemistry of rivers and streams. Here we present results of multi-year studies designed to assess the seasonal and spatial variability of DOM quantity and quality for 57 North American Rivers. DOM concentrations and composition, based on DOM fractionation on XAD resins, ultraviolet (UV)/visible absorption and fluorescence spectroscopic analyses, and specific compound analyses, varied greatly both between sites and seasonally within a given site. DOM in these rivers exhibited a wide range of concentration (4000 µM C* L-1) and specific ultra-violet absorbance at 254 nm (SUVA254) (0.6 to 5 L *mg C-1 *m-1), an optical measurement that is an indicator of aromatic carbon content. In almost all systems, UV absorbance measured at specific wavelengths (e.g. 254 nm) correlated strongly with DOM and hydrophobic organic acid (HPOA) content (aquatic humic substances). The relationships between dissolved organic carbon (DOC) concentration and absorbance for the range of systems were quite variable due to

  13. Organic Matter Dynamics in Soils Regenerating from Degraded ...

    African Journals Online (AJOL)

    The area of secondary forest (SF) regenerating from degraded abandoned rubber (Hevea brasiliensis) plantation is increasing in the rainforest zone of south southern Nigeria; however, the build-up of soil organic matter following abandonment is not well understood. This study examined the build-up of soil organic matter in ...

  14. Seasonal distribution of organic matter in mangrove environment of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.

    Water and sediments were studied for the distribution of suspended matter, organic carbon and nitrogen Suspended matter ranged from 3-373 mg.l-1 while particulate organic carbon (POC) from 0.03-9.94 mg.l-1 POC value showed significant correlation...

  15. Organic matter dynamics and N mineralization in grassland soils

    NARCIS (Netherlands)

    Hassink, J.

    1995-01-01


    The aims of this study are i) to improve our understanding of the interactions between soil texturelsoil structure, soil organic matter, soil biota and mineralization in grassland soils, ii) to develop a procedure that yields soil organic matter fractions that can be determined directly

  16. Mineral surface–organic matter interactions: basics and applications

    International Nuclear Information System (INIS)

    Valdrè, G; Moro, D; Ulian, G

    2012-01-01

    The ability to control the binding of biological and organic molecules to a crystal surface is central in several fields; for example, in biotechnology, catalysis, molecular microarrays, biosensors preparation and environmental sciences. The nano-morphology and nanostructure at the surface may have physico-chemical properties that are very different from those of the underlying mineral substrate. Recent developments in scanning probe microscopy (SPM) have widened the spectrum of possible investigations that can be performed at the nanometric level on the surface of minerals. They range from the study of physical properties such as surface potential, electric field topological determination, Brønsted–Lowry site distributions, to chemical and spectroscopic analysis in air, in liquid or in gaseous environments. After an introduction to SPM modes of operation and new SPM-based technological developments, we will present recent examples of applications in the study of interactions between organic matter and mineral surface and report on the advances in knowledge that have been made by the use of scanning probe microscopy.

  17. Methods for Determining Organic Matter and Colour in Water

    Directory of Open Access Journals (Sweden)

    Ramunė Albrektienė

    2011-02-01

    Full Text Available The article examines different methods for determining organic matter and colour in water. Most of organic compounds in water have a humic substance. These substances frequently form complexes with iron. Humic matter gives water a yellow-brownish colour. Water filtration through conventional sand filters does not remove colour and organic compounds, and therefore complicated water treatment methods shall be applied. The methods utilized for organic matter determination in water included research on total organic carbon, permanganate index and the bichromate number of UV absorption of 254 nm wave length. The obtained results showed the greatest dependence between water colour and permanganate index. However, UV adsorption could be used for organic matter determination during the operation of a water treatment plant and the start-up of plants as easy and fast methods.Article in Lithuanian

  18. Quantifying the degradation of organic matter in marine sediments: A review and synthesis

    Science.gov (United States)

    Arndt, Sandra; Jørgensen, B. B.; LaRowe, D. E.; Middelburg, J. J.; Pancost, R. D.; Regnier, P.

    2013-08-01

    Quantifying the rates of biogeochemical processes in marine sediments is essential for understanding global element cycles and climate change. Because organic matter degradation is the engine behind benthic dynamics, deciphering the impact that various forces have on this process is central to determining the evolution of the Earth system. Therefore, recent developments in the quantitative modeling of organic matter degradation in marine sediments are critically reviewed. The first part of the review synthesizes the main chemical, biological and physical factors that control organic matter degradation in sediments while the second part provides a general review of the mathematical formulations used to model these processes and the third part evaluates their application over different spatial and temporal scales. Key transport mechanisms in sedimentary environments are summarized and the mathematical formulation of the organic matter degradation rate law is described in detail. The roles of enzyme kinetics, bioenergetics, temperature and biomass growth in particular are highlighted. Alternative model approaches that quantify the degradation rate constant are also critically compared. In the third part of the review, the capability of different model approaches to extrapolate organic matter degradation rates over a broad range of temporal and spatial scales is assessed. In addition, the structure, functions and parameterization of more than 250 published models of organic matter degradation in marine sediments are analyzed. The large range of published model parameters illustrates the complex nature of organic matter dynamics, and, thus, the limited transferability of these parameters from one site to another. Compiled model parameters do not reveal a statistically significant correlation with single environmental characteristics such as water depth, deposition rate or organic matter flux. The lack of a generic framework that allows for model parameters to be

  19. POLAR ORGANIC CHEMICAL INTEGRATIVE SAMPLING ...

    Science.gov (United States)

    The purpose of the research presented in this paper is two-fold: (1) to demonstrate the 4 coupling of two state-of-the-art techniques: a time-weighted polar organic integrative sampler (POCIS) and micro-liquid chromatography-electrospray/ion trap mass spectrometry (u-LC-6 ES/ITMS); and (2) the assessment of these methodologies in a real-world environment -wastewater effluent - for detecting six drugs (four prescription and two illicit). In the effluent from three wastewater treatment plants (WWTP), azithromycin was detected at concentrations ranging from 15ng/L to 66ng/L, equivalent to the total annual release of 0.4 -4 kg into the receiving waters. Detected and confirmed in the effluent from two WWTPs were two illicit drugs methamphetamine and methylenedioxymethamphetamine (MDMA), at 2ng/L and 0.5ng/L, respectively. While the ecotoxicological significance of drugs in environmental matrices, particularly water, has not been closely examined, it can only be surmised that these substances have the potential to adversely affect biota that are continuously exposed to them even at very low levels. The potential for chronic affects on human health is also unknown, but of increasing concern due to the multi use character of water, particularly in densely populated arid areas. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality

  20. The chemical composition and in vitro dry matter digestibility of ...

    African Journals Online (AJOL)

    Leendert Snynan

    Crop residues in the summer rainfall area of South Africa fulfill a strategic role in the fodder flow program ... This value is high when compared with in vitro organic matter digestibility values reported for wheat straw. (38.9%) ... Sunflower-cob residues seem to be a forage with a high energy value that might be suitable for use.

  1. Natural organic matter to enhance electrokinetic transport of PAH

    Energy Technology Data Exchange (ETDEWEB)

    Suer, P.; Joensson, S.; Allard, B. [Man-Technology-Environment Research Centre, Oerebro Univ. (Sweden)

    2001-07-01

    The remediation of contaminated soil can be enhanced with natural organic matter (NOM) as a complexing agent for pollutants. NOM has both hydrophobic and acidic properties, so that it is charged and thus subject to electroremediation. At the same time many contaminants have a high affinity for organic matter. Organic matter was produced in situ in an electric field or added in solute form. The resulting dissolved organic matter was transported towards the cathode, probably by cationic colloids. Produced dissolved organic matter included high molecular weight molecules near the cathode, at the site of pH buffering. Pyrene and phenanthrene were likewise transported towards the cathode. Movement was small but distinctive in 2-day experiments. Clay influence the soil/water distribution of the PAH but no effect on the total transport could be discerned. The presence of solid organic matter in the soil removed all PAH from the water phase, even though the concentration of organic matter in the water phase was high as well. (orig.)

  2. Pinus afforestation in South Brazilian highlands: soil chemical attributes and organic matter composition Florestamento com Pinus em solos de altitude do Sul do Brasil: atributos químicos e matéria orgânica do solo

    Directory of Open Access Journals (Sweden)

    Deborah Pinheiro Dick

    2011-04-01

    Full Text Available In the last three decades, exotic tree species are being introduced in the natural pastures of the highlands located at the northeastern part of Rio Grande do Sul State (RS, Brazil. This alteration of land use may impart drastic changes in the soil attributes. In this context, this work aimed to evaluate the impact of Pinus taeda afforestation on soil chemical attributes and organic matter (SOM composition in Leptosols from Campos de Cima da Serra, RS. Soil samples under eight year old (Pi8 and 30 year old (Pi30 Pinus plantations and under native pasture (NP were studied. Contents of exchangeable cations and of micronutrients and soil pH were determined. The SOM composition was investigated by means of elemental analyses and FTIR spectroscopy. The soil under pasture had a higher content of nutrients and of SOM in comparison to Pinus soils, reflecting the higher input and decomposition rate of the below ground added residue in the grassland environment. The SOM in pasture soils showed a higher content of carbohydrate and of structures derived from microbial metabolism. Besides the depletion of nutrients and of SOM, Pinus afforestation affected the SOM quality: following afforestation, the proportion of chemically recalcitrant structures and of carboxylic groups increased, whereas N-containing groups decreased.Nas três últimas décadas, o cultivo de espécies exóticas vem sendo introduzido nas áreas de pastagem de solos de altitude localizados na região nordeste do Estado do rio Grande do Sul. Essa alteração de uso do solo pode causar mudanças drásticas nos atributos do solo. Avaliou-se o impacto do florestamento com Pinus Taeda nos atributos químicos e na composição da matéria orgânica (MOS de Neossolos Litólicos dos Campos de Cima da Serra, RS. Foram estudadas amostras de solo sob plantação de Pinus há oito (Pi8 e há 30 anos (Pi30 e sob pastagem natural (NP, sendo determinados os teores de cátions trocáveis e de

  3. Biologically Active Organic Matter in Soils of European Russia

    Science.gov (United States)

    Semenov, V. M.; Kogut, B. M.; Zinyakova, N. B.; Masyutenko, N. P.; Malyukova, L. S.; Lebedeva, T. N.; Tulina, A. S.

    2018-04-01

    Experimental and literature data on the contents and stocks of active organic matter in 200 soil samples from the forest-tundra, southern-taiga, deciduous-forest, forest-steppe, dry-steppe, semidesert, and subtropical zones have been generalized. Natural lands, agrocenoses, treatments of long-term field experiments (bare fallow, unfertilized and fertilized crop rotations, perennial plantations), and different layers of soil profile are presented. Sphagnum peat and humus-peat soil in the tundra and forest-tundra zones are characterized by a very high content of active organic matter (300-600 mg C/100 g). Among the zonal soils, the content of active organic matter increases from the medium (75-150 mg C/100 g) to the high (150-300 mg C/100 g) level when going from soddy-podzolic soil to gray forest and dark-gray forest soils and then to leached chernozem. In the series from typical chernozem to ordinary and southern chernozem and chestnut and brown semidesert soils, a decrease in the content of active organic matter to the low (35-75 mg C/100 g) and very low (organic matter. Most arable soils are mainly characterized by low or very low contents of active organic matter. In the upper layers of soils, active organic matter makes up 1.2-11.1% of total Corg. The profile distribution of active organic matter in the studied soils coincides with that of Corg: their contents appreciably decrease with depth, except for brown semidesert soil. The stocks of active organic matter vary from 0.4 to 5.4 t/ha in the layer of 0-20 cm and from 1.0 to 12.4/ha in the layer of 0-50 cm of different soil types.

  4. Missing links in the root-soil organic matter continuum

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Sarah L. [Argonne National Laboratory (ANL); Iversen, Colleen M [ORNL

    2009-01-01

    The soil environment remains one of the most complex and poorly understood research frontiers in ecology. Soil organic matter (SOM), which spans a continuum from fresh detritus to highly processed, mineral-associated organic matter, is the foundation of sustainable terrestrial ecosystems. Heterogeneous SOM pools are fueled by inputs from living and dead plants, driven by the activity of micro- and mesofauna, and are shaped by a multitude of abiotic factors. The specialization required to measure unseen processes that occur on a wide range of spatial and temporal scales has led to the partitioning of soil ecology research across several disciplines. In the organized oral session 'Missing links in the root-soil organic matter continuum' at the annual Ecological Society of America meeting in Albuquerque, NM, USA, we joined the call for greater communication and collaboration among ecologists who work at the root-soil interface (e.g. Coleman, 2008). Our goal was to bridge the gap between scientific disciplines and to synthesize disconnected pieces of knowledge from root-centric and soil-centric studies into an integrated understanding of belowground ecosystem processes. We focused this report around three compelling themes that arose from the session: (1) the influence of the rhizosphere on SOM cycling, (2) the role of soil heterotrophs in driving the transformation of root detritus to SOM, and (3) the controlling influence of the soil environment on SOM dynamics. We conclude with a discussion of new approaches for gathering data to bridge gaps in the root-SOM continuum and to inform the next generation of ecosystem models. Although leaf litter has often been considered to be the main source of organic inputs to soil, Ann Russell synthesized a convincing body of work demonstrating that roots, rather than surface residues, control the accumulation of SOM in a variety of ecosystems. Living roots, which are chemically diverse and highly dynamic, also influence a

  5. Aqueous organic chemistry in the atmosphere: sources and chemical processing of organic aerosols.

    Science.gov (United States)

    McNeill, V Faye

    2015-02-03

    Over the past decade, it has become clear that aqueous chemical processes occurring in cloud droplets and wet atmospheric particles are an important source of organic atmospheric particulate matter. Reactions of water-soluble volatile (or semivolatile) organic gases (VOCs or SVOCs) in these aqueous media lead to the formation of highly oxidized organic particulate matter (secondary organic aerosol; SOA) and key tracer species, such as organosulfates. These processes are often driven by a combination of anthropogenic and biogenic emissions, and therefore their accurate representation in models is important for effective air quality management. Despite considerable progress, mechanistic understanding of some key aqueous processes is still lacking, and these pathways are incompletely represented in 3D atmospheric chemistry and air quality models. In this article, the concepts, historical context, and current state of the science of aqueous pathways of SOA formation are discussed.

  6. Including chemical-related impact categories in LCA on printed matter does it matter?

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred; Hansen, Morten Søes; Hauschild, Michael Zwicky

    2004-01-01

    global warming, acidification and nutrification. The studies focus on energy consumption including the emissions and impact categories related to energy. The chemical-related impact categories comprising ecotoxicity and human toxicity are not included at all or only to a limited degree. In this paper we...... include these chemical-related impact categories by making use of some of the newest knowledge about emissions from the production at the printing industry combined with knowledge about the composition of the printing materials used during the production of offset printed matter. This paper is based...... printed matter produced on a fictitious sheet feed offset printing industry in Europe has been identified and shown in Figure 1 (light bars). „Ï The effect of including the chemical related impact categories is substantial as shown in Figure 1, e.g. the importance of paper is reduced from 67% to 31...

  7. Molecular simulation of a model of dissolved organic matter.

    Science.gov (United States)

    Sutton, Rebecca; Sposito, Garrison; Diallo, Mamadou S; Schulten, Hans-Rolf

    2005-08-01

    A series of atomistic simulations was performed to assess the ability of the Schulten dissolved organic matter (DOM) molecule, a well-established model humic molecule, to reproduce the physical and chemical behavior of natural humic substances. The unhydrated DOM molecule had a bulk density value appropriate to humic matter, but its Hildebrand solubility parameter was lower than the range of current experimental estimates. Under hydrated conditions, the DOM molecule went through conformational adjustments that resulted in disruption of intramolecular hydrogen bonds (H-bonds), although few water molecules penetrated the organic interior. The radius of gyration of the hydrated DOM molecule was similar to those measured for aquatic humic substances. To simulate humic materials under aqueous conditions with varying pH levels, carboxyl groups were deprotonated, and hydrated Na+ or Ca2+ were added to balance the resulting negative charge. Because of intrusion of the cation hydrates, the model metal-humic structures were more porous, had greater solvent-accessible surface areas, and formed more H-bonds with water than the protonated, hydrated DOM molecule. Relative to Na+, Ca2+ was both more strongly bound to carboxylate groups and more fully hydrated. This difference was attributed to the higher charge of the divalent cation. The Ca-DOM hydrate, however, featured fewer H-bonds than the Na-DOM hydrate, perhaps because of the reduced orientational freedom of organic moieties and water molecules imposed by Ca2+. The present work is, to our knowledge, the first rigorous computational exploration regarding the behavior of a model humic molecule under a range of physical conditions typical of soil and water systems.

  8. Spectral band selection for classification of soil organic matter content

    Science.gov (United States)

    Henderson, Tracey L.; Szilagyi, Andrea; Baumgardner, Marion F.; Chen, Chih-Chien Thomas; Landgrebe, David A.

    1989-01-01

    This paper describes the spectral-band-selection (SBS) algorithm of Chen and Landgrebe (1987, 1988, and 1989) and uses the algorithm to classify the organic matter content in the earth's surface soil. The effectiveness of the algorithm was evaluated comparing the results of classification of the soil organic matter using SBS bands with those obtained using Landsat MSS bands and TM bands, showing that the algorithm was successful in finding important spectral bands for classification of organic matter content. Using the calculated bands, the probabilities of correct classification for climate-stratified data were found to range from 0.910 to 0.980.

  9. Elucidating Adsorptive Fractions of Natural Organic Matter on Carbon Nanotubes.

    Science.gov (United States)

    Ateia, Mohamed; Apul, Onur G; Shimizu, Yuta; Muflihah, Astri; Yoshimura, Chihiro; Karanfil, Tanju

    2017-06-20

    Natural organic matter (NOM) is a heterogeneous mixture of organic compounds that is omnipresent in natural waters. To date, the understanding of the adsorption of NOM components by carbon nanotubes (CNTs) is limited because of the limited number of comprehensive studies in the literature examining the adsorption of NOM by CNTs. In this study, 11 standard NOM samples from various sources were characterized, and their adsorption behaviors on four different CNTs were examined side-by-side using total organic carbon, fluorescence, UV-visible spectroscopy, and high-performance size-exclusion chromatography (HPSEC) analysis. Adsorption was influenced by the chemical properties of the NOM, including aromaticity, degree of oxidation, and carboxylic acidity. Fluorescence excitation-emission matrix (EEM) analysis showed preferential adsorption of decomposed and terrestrial-derived NOM compared to freshly produced and microbial-derived NOM. HPSEC analysis revealed preferential adsorption of fractions in the molecular weight range of 0.5-2 kDa for humic acids but in the molecular weight range of 1-3 kDa for all fulvic acids and reverse-osmosis isolates. However, the smallest characterized fraction (MW < 0.4 kDa) in all samples did not adsorb on the CNTs.

  10. Sorptive stabilization of organic matter by amorphous Al hydroxide

    NARCIS (Netherlands)

    Schneider, M.P.W.; Scheel, T.; Mikutta, R.; van Hees, P.; Kaiser, K.; Kalbitz, K.

    2010-01-01

    Amorphous Al hydroxides (am-Al(OH)(3)) strongly sorb and by this means likely protect dissolved organic matter (OM) against microbial decay in soils. We carried out batch sorption experiments (pH 4.5; 40 mg organic C L-1) with OM extracted from organic horizons under a Norway spruce and a European

  11. Investigation of the organic matter in inactive nuclear tank liquids

    International Nuclear Information System (INIS)

    Schenley, R.L.; Griest, W.H.

    1990-08-01

    Environmental Protection Agency (EPA) methodology for regulatory organics fails to account for the organic matter that is suggested by total organic carbon (TOC) analysis in the Oak Ridge National Laboratory (ORNL) inactive nuclear waste-tank liquids and sludges. Identification and measurement of the total organics are needed to select appropriate waste treatment technologies. An initial investigation was made of the nature of the organics in several waste-tank liquids. This report details the analysis of ORNL wastes

  12. Mitigation of algal organic matter released from Chaetoceros affinis and Hymenomonas by in situ generated ferrate

    KAUST Repository

    Deka, Bhaskar Jyoti; Jeong, Sanghyun; AlizadehTabatabai, S.Assiyeh; An, Alicia Kyoungjin

    2018-01-01

    This study demonstrates the application of in situ ferrate (Fe(VI)) for the efficient removal of dissolved algal organic matter (AOM) from seawater. Sodium hypochlorite (NaOCl) and ferric (Fe(III)) were used to produce in situ Fe(VI) by wet chemical

  13. Organic matter of subsoil horizons under broadleaved forest: Highly processed or labile and plant-derived?

    NARCIS (Netherlands)

    Vancampenhout, K.; Vos, de B.; Wouters, K.; Swennen, R.; Buurman, P.

    2012-01-01

    Between 30 and 63% of the soil organic matter (SOM) is stored below 30 cm, making subsoil-SOM an important source and sink in the global carbon cycle. Nevertheless, detailed information on the composition of subsoil-SOM remains scarce. This study aims to evaluate the chemical composition of SOM in

  14. Global effects of agriculture on fluvial dissolved organic matter

    DEFF Research Database (Denmark)

    Graeber, Daniel; Boëchat, Iola; Encina, Francisco

    2015-01-01

    Agricultural land covers approximately 40% of Earth’s land surface and affects hydromorphological, biogeochemical and ecological characteristics of fluvial networks. In the northern temperate region, agriculture also strongly affects the amount and molecular composition of dissolved organic matter...

  15. Soil organic matter dynamics and the global carbon cycle

    International Nuclear Information System (INIS)

    Post, W.M.; Emanuel, W.R.; King, A.W.

    1992-01-01

    The large size and potentially long residence time of the soil organic matter pool make it an important component of the global carbon cycle. Net terrestrial primary production of about 60 Pg C·yr -1 is, over a several-year period of time, balanced by an equivalent flux of litter production and subsequent decomposition of detritus and soil organic matter. We will review many of the major factors that influence soil organic matter dynamics that need to be explicitly considered in development of global estimates of carbon turnover in the world's soils. We will also discuss current decomposition models that are general enough to be used to develop a representation of global soil organic matter dynamics

  16. Behaviour of organic matters in uranium ore processing

    International Nuclear Information System (INIS)

    Wu Sanmin

    1991-01-01

    The oxidation-reduction behaviour of organic matters in the course of oxidation roasting, acid leaching and alkali leaching, the regeneration of humic acid and the consumption of reagents are described. The mineralogical characteristics of the organic matter samples were studied. The results show that its organic matter rich in volatile carbon and with the shorter evolutionary process and lower association is easily oxidized with higher consumption of oxidant during its acid leaching; it is easily oxidized with forming humic acid during alkali leaching; and pretreating it by oxidation roasting is beneficial to the oxidation of uranium. On the contrary, the organic matter rich in fixed carbon, and with longer evolutionary process and higher association is difficultly oxidized with lower consumption of oxidant during its acid leaching; it is difficult to regenerate humic acid for it during alkali leaching; and the uranium can be easily reduced and the leaching performance of uranium can be lowered

  17. Composition of structural fragments and the mineralization rate of organic matter in zonal soils

    Science.gov (United States)

    Larionova, A. A.; Zolotareva, B. N.; Kolyagin, Yu. G.; Kvitkina, A. K.; Kaganov, V. V.; Kudeyarov, V. N.

    2015-10-01

    Comparative analysis of the climatic characteristics and the recalcitrance against decomposition of organic matter in the zonal soil series of European Russia, from peat surface-gley tundra soil to brown semidesert soil, has assessed the relationships between the period of biological activity, the content of chemically stable functional groups, and the mineralization of humus. The stability of organic matter has been determined from the ratio of functional groups using the solid-state 13C NMR spectroscopy of soil samples and the direct measurements of organic matter mineralization from CO2 emission. A statistically significant correlation has been found between the period of biological activity and the humification indices: the CHA/CFA ratio, the aromaticity, and the alkyl/ O-alkyl ratio in organic matter. The closest correlation has been observed between the period of biological activity and the alkyl/ O-alkyl ratio; therefore, this parameter can be an important indicator of the soil humus status. A poor correlation between the mineralization rate and the content of chemically stable functional groups in soil organic matter has been revealed for the studied soil series. At the same time, the lowest rate of carbon mineralization has been observed in southern chernozem characterized by the maximum content of aromatic groups (21% Corg) and surface-gley peat tundra soil, where an extremely high content of unsubstituted CH2 and CH3 alkyl groups (41% Corg) has been noted.

  18. Molybdenum isotope fractionation during adsorption to organic matter

    Science.gov (United States)

    King, Elizabeth K.; Perakis, Steven; Pett-Ridge, Julie C.

    2018-01-01

    Organic matter is of emerging interest as a control on molybdenum (Mo) biogeochemistry, and information on isotope fractionation during adsorption to organic matter can improve interpretations of Mo isotope variations in natural settings. Molybdenum isotope fractionation was investigated during adsorption onto insolubilized humic acid (IHA), a surrogate for organic matter, as a function of time (2–170 h) and pH (2–7). For the time series experiment performed at pH 4.2, the average Mo isotope fractionation between the solution and the IHA (Δ98Mosolution-IHA) was 1.39‰ (± 0.16‰, 2σ, based on 98Mo/95Mo relative to the NIST 3134 standard) at steady state. For the pH series experiment, Mo adsorption decreased as pH increased from 2.0 to 6.9, and the Δ98Mosolution-IHA increased from 0.82‰ to 1.79‰. We also evaluated natural Mo isotope patterns in precipitation, foliage, organic horizon, surface mineral soil, and bedrock from 12 forested sites in the Oregon Coast Range. The average Mo isotope offset observed between precipitation and organic (O) horizon soil was 2.1‰, with light Mo isotopes adsorbing preferentially to organic matter. Fractionation during adsorption to organic matter is similar in magnitude and direction to prior observations of Mo fractionation during adsorption to Fe- and Mn- (oxyhydr)oxides. Our finding that organic matter influences Mo isotope composition has important implications for the role of organic matter as a driver of trace metal retention and isotopic fractionation.

  19. SNC Meteorites, Organic Matter and a New Look at Viking

    Science.gov (United States)

    Warmflash, David M.; Clemett, Simon J.; McKay, David S.

    2001-01-01

    experiment, a solution containing C-14 labeled organic compounds was injected into soil samples. The detection of radioactivity in the overhead space would indicate that one or more of the substrates had been chemically converted into a carbon-containing gas. To serve as a control, some samples were heated enough to destroy most known terrestrial microbes so that an indication for life would be a positive response from unheated samples and a negative response from heated samples. On Mars, the LR results had met minimum criteria for a biological interpretation but due to the GC-MS results, the LR responses were later attributed to putative soil inorganic oxidants. Since the time of Viking, studies have been carried out with the objective of determining an oxidant or combination of oxidants that might exist on Mars and have produced the observed kinetics of the LR response. To date, no such agent has been found that produces all aspects of the LR results on Mars. While the above considerations in no way imply the existence of life forms at the two Viking landing sites, inorganic and biological explanations for the Viking LR data should now be considered equally plausible until more complete studies of the Martian surface are carried out. Therefore, in light of the SNC meteorites data and their implications for the possibility of organic matter near or on the Martian surface the Viking biology experiments should thus be seen, not as failures for their inability to provide unambiguous evidence for or against Martian life, but as a foundation for the development of future life-detection instruments. Additional information is contained in the original extended abstract.

  20. Organic Matter in Space (IAU S251)

    Science.gov (United States)

    Kwok, Sun; Sanford, Scott

    2009-01-01

    Preface; From the local organising committee; Organising committee; Conference participants; Opening address of Symposium 251 C. Cesarsky; Session I. Observations of organic compounds beyond the Solar System William Irvine, Ewine van Dishoeck, Yvonne Pendleton and Hans Olofsson; Session II. Organic compounds within the Solar System Scott Sandford, Ernst Zinner and Dale Cruikshank; Session III. Laboratory analogues of organic compounds in space Max Bernstein and Thomas Henning; Banquet speech; Author index; Object index.

  1. Toward an experimental synthesis of the chondritic insoluble organic matter

    Science.gov (United States)

    Biron, Kasia; Derenne, Sylvie; Robert, FrançOis; Rouzaud, Jean-NoëL.

    2015-08-01

    Based on the statistical model proposed for the molecular structure of the insoluble organic matter (IOM) isolated from the Murchison meteorite, it was recently proposed that, in the solar T-Tauri disk regions where (photo)dissociation of gaseous molecules takes place, aromatics result from the cyclization/aromatization of short aliphatics. This hypothesis is tested in this study, with n-alkanes being submitted to high-frequency discharge at low pressure. The contamination issue was eliminated using deuterated precursor. IOM was formed and studied using solid-state nuclear magnetic resonance, pyrolysis coupled to gas chromatography and mass spectrometry, RuO4 oxidation, and high-resolution transmission electron microscopy. It exhibits numerous similarities at the molecular level with the hydrocarbon backbone of the natural IOM, reinforcing the idea that the initial precursors of the IOM were originally chains in the gas. Moreover, a fine comparison between the chemical structure of several meteorite IOM suggests either that (i) the meteorite IOMs share a common precursor standing for the synthetic IOM or that (ii) the slight differences between the meteorite IOMs reflect differences in their environment at the time of their formation i.e., related to plasma temperature that, in turn, dictates the dissociation-recombination rates of organic fragments.

  2. Using thermal analysis to evaluate the fire effects on organic matter content of Andisols

    Directory of Open Access Journals (Sweden)

    J. Neris

    2013-09-01

    Full Text Available Soil organic compounds play a relevant role in aggregate stability and thus, in the susceptibility of soils to erosion. Thermal analysis (N2 and air and chemical oxidation techniques (dichromate and permanganate oxidation were used to evaluate the effects of a forest fire on the organic matter of Andisols. Both thermal analysis and chemical methods showed a decrease in the organic matter content and an increase in the recalcitrance of the remaining organic compounds in the burned zones. Thermal analysis indicated an increase in the thermal stability of the organic compounds of fire-affected soils and a lower content of both labile and recalcitrant pools as a consequence of the fire. However, this decrease was relatively higher in the labile pool and lower in the recalcitrant one, indicative of an increase in the recalcitrance of the remaining organic compounds. Apparently, black carbon did not burn under our experimental conditions. Under N2, the results showed a lower labile and a higher recalcitrant and refractory contents in burned and some unburned soils, possibly due to the lower decomposition rate under N2 flux. Thermal analysis using O2 and the chemical techniques showed a positive relation, but noticeable differences in the total amount of the labile pool. Thermal analysis methods provide direct quantitative information useful to characterize the soil organic matter quality and to evaluate the effects of fire on soils.

  3. The Effect of paper mill waste and sewage sludge amendments on soil organic matter

    Science.gov (United States)

    Méndez, Ana; Barriga, Sandra; Guerrero, Francisca; Gascó, Gabriel

    2013-04-01

    In general, Mediterranean soils have low organic matter content, due to the climate characteristics of this region and inadequate land management. Traditionally, organic wastes such as manure are used as amendment in order to improve the soil quality, increasing soil fertility by the accumulation of nitrogen, phosphorus and other plant nutrients in the soil. In the last decade, other anthropogenic organic wastes such as sewage sludge or paper waste materials have been studied as soil amendments to improve physical, chemical and biological properties of soils. The objective of the present work was to study the influence of waste from a paper mill and sewage sludge amendments on soil organic matter. For this reason, soil organic matter evolution was studied using thermogravimetric analysis (TGA), the derivative (dTG) and differential thermal analysis (DTA). Thermal analytical techniques have the advantage of using full samples without pre-treatments and have been extensively used to study the evolution of organic matter in soils, to evaluate composting process or to study the evolution of organic matter of growing media.

  4. Decomposition of litter and soil organic matter - Can we distinguish a mechanism for soil organic matter buildup ?

    International Nuclear Information System (INIS)

    Berg, B.; Johansson, M.B.; McClaugherty, C.; Virzo de Santo, A.; Ekbohm, G.

    1995-01-01

    This synthesis paper presents a model for estimating the buildup of soil organic matter in various types of coniferous forests. The knowledge used was obtained from a well-studied forest with good litterfall data, decomposition information and validation measurements of the soil organic matter layer. By constructing a simple model for litterfall, and the information on maximum decomposition levels for litter, we could estimate the annual increase in soil organic matter and extend this to encompass stand age. The validation measurement and the estimated amount of soil organic matter differed by about 8 or 26% over a 120-yr period, depending on the litterfall model. The estimated increased storage of soil organic matter as a consequence of climate change was found to be drastic. We thus found that the soil organic matter layer would grow about four times as fast as a result of the needle component only. This estimate was based on a comparison between latitudes with a difference of 17 degrees. 35 refs, 7 figs, 3 tabs

  5. Geological factors of the isotopic distribution of carbon of organic matter in sedimentary rocks

    International Nuclear Information System (INIS)

    Maass, J.

    1981-01-01

    The isotope ratio of carbon of fossile organic matter can be regarded as a definite criterion of its genetic origin. As the biofacial character of organic matter, especially the chemical composition (H/C-ratio), decisively influences the mode and quantity of the potential hydrocarbon production, isotopic analysis is an essential method for the prognostic evaluation of sedimentary basins with regard to their oil and gas perspectives. The genetic relations to the parent substance continue in the bituminization and coalification products and make it possible to apply the isotopic analysis of carbon to prospection work for hydrocarbons. (author)

  6. Organic Matter Quality and its Influence on Carbon Turnover and Stabilization in Northern Peatlands

    Science.gov (United States)

    Turetsky, M. R.; Wieder, R. K.

    2002-12-01

    Peatlands cover 3-5 % of the world's ice-free land area, but store about 33 % of global terrestrial soil carbon. Peat accumulation in northern regions generally is controlled by slow decomposition, which may be limited by cold temperatures and water-logging. Poor organic matter quality also may limit decay, and microbial activity in peatlands likely is regulated by the availability of labile carbon and/or nutrients. Conversely, carbon in recalcitrant soil structures may be chemically protected from microbial decay, particularly in peatlands where carbon can be buried in anaerobic soils. Soil organic matter quality is controlled by plant litter chemical composition and the susceptibility of organic compounds to decomposition through time. There are a number of techniques available for characterizing organic quality, ranging from chemical proximate or elemental analysis to more qualitative methods such as nuclear magenetic resonance, pyrolysis/mass spectroscopy, and Fourier transform infrared spectroscopy. We generally have relied on proximate analysis for quantitative determination of several organic fractions (i.e., water-soluble carbohydrates, soluble nonpolars, water-soluble phenolics, holocellulose, and acid insoluble material). Our approaches to studying organic matter quality in relation to C turnover in peatlands include 1) 14C labelling of peatland vegetation along a latitudinal gradient in North America, allowing us to follow the fate of 14C tracer in belowground organic fractions under varying climates, 2) litter bag studies focusing on the role of individual moss species in litter quality and organic matter decomposition, and 3) laboratory incubations of peat to explore relationships between organic matter quality and decay. These studies suggest that proximate organic fractions vary in lability, but that turnover of organic matter is influenced both by plant species and climate. Across boreal peatlands, measures of soil recalcitrance such as acid

  7. Seafloor ecosystem functioning: the importance of organic matter priming

    NARCIS (Netherlands)

    Van Nugteren, P.; Moodley, L.; Brummer, G.J.; Heip, C.H.R.; Herman, P.M.J.; Middelburg, J.J.

    2009-01-01

    Organic matter (OM) remineralization may be considered a key function of the benthic compartment of marine ecosystems and in this study we investigated if the input of labile organic carbon alters mineralization of indigenous sediment OM (OM priming). Using 13C-enriched diatoms as labile tracer

  8. Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

    Science.gov (United States)

    Campbell, Brian

    2010-01-01

    Copper fungicides and bactericides are often used in tomato cultivation and can cause toxic Cu levels in soils. In order to combat this, organic matter can be applied to induce chelation reactions and form a soluble complex by which much of the Cu can leach out of the soil profile or be taken up safely by plants. Organic acids such as citric,…

  9. Microbial bioavailability regulates organic matter preservation in marine sediments

    NARCIS (Netherlands)

    Koho, K. A.; Nierop, K. G. J.; Moodley, L.; Middelburg, J. J.; Pozzato, L.; Soetaert, K.; van der Plicht, J.; Reichart, G-J.; Herndl, G.

    2013-01-01

    Burial of organic matter (OM) plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism

  10. Tritium in organic matter around Krsko Nuclear Power Plant

    International Nuclear Information System (INIS)

    Kristof, Romana; Zorko, Benjamin; Kozar Logar, Jasmina; Kosenina, Suzana

    2017-01-01

    The aim of the research was to obtain first results of tritium in the organic matter of environmental samples in the vicinity of Krsko NPP. The emphasis was on the layout of suitable sampling network of crops and fruits in nearby agricultural area. Method for determination of tritium in organic matter in the form of Tissue Free Water Tritium (TFWT) and Organically Bound Tritium (OBT) has been implemented. Capabilities of the methods were tested on real environmental samples and its findings were compared to modeled activities of tritium from atmospheric releases and literature based results of TFWT and OBT. (author)

  11. Computing chemical organizations in biological networks.

    Science.gov (United States)

    Centler, Florian; Kaleta, Christoph; di Fenizio, Pietro Speroni; Dittrich, Peter

    2008-07-15

    Novel techniques are required to analyze computational models of intracellular processes as they increase steadily in size and complexity. The theory of chemical organizations has recently been introduced as such a technique that links the topology of biochemical reaction network models to their dynamical repertoire. The network is decomposed into algebraically closed and self-maintaining subnetworks called organizations. They form a hierarchy representing all feasible system states including all steady states. We present three algorithms to compute the hierarchy of organizations for network models provided in SBML format. Two of them compute the complete organization hierarchy, while the third one uses heuristics to obtain a subset of all organizations for large models. While the constructive approach computes the hierarchy starting from the smallest organization in a bottom-up fashion, the flux-based approach employs self-maintaining flux distributions to determine organizations. A runtime comparison on 16 different network models of natural systems showed that none of the two exhaustive algorithms is superior in all cases. Studying a 'genome-scale' network model with 762 species and 1193 reactions, we demonstrate how the organization hierarchy helps to uncover the model structure and allows to evaluate the model's quality, for example by detecting components and subsystems of the model whose maintenance is not explained by the model. All data and a Java implementation that plugs into the Systems Biology Workbench is available from http://www.minet.uni-jena.de/csb/prj/ot/tools.

  12. Transplanting an organization: how does culture matter.

    Science.gov (United States)

    Munich, Richard L

    2011-01-01

    Cultural differences are often cited as a major obstacle to the successful transition/integration into new situations of organizations. In this contribution, the author details the changing cultural factors impacting the operation and move of the Menninger Clinic from autonomous status to an affiliation with and first year of operation in the Baylor College of Medicine and Methodist Hospital Health Care System. Both functional and dysfunctional consequences are outlined, and specific examples illustrate how the organization's leadership and staff struggled to adapt during this complicated process. Based on the experience within the Clinic, general recommendations for managing such an acculturation are provided.

  13. Response of organic matter quality in permafrost soils to warming

    Science.gov (United States)

    Plaza, C.; Pegoraro, E.; Schuur, E.

    2016-12-01

    Global warming is predicted to thaw large quantities of the perennially frozen organic matter stored in northern permafrost soils. Upon thaw, this organic matter will be exposed to lateral export to water bodies and to microbial decomposition, which may exacerbate climate change by releasing significant amounts of greenhouse gases. To gain an insight into these processes, we investigated how the quality of permafrost soil organic matter responded to five years of warming. In particular, we sampled control and experimentally warmed soils in 2009 and 2013 from an experiment established in 2008 in a moist acidic tundra ecosystem in Healy, Alaska. We examined surface organic (0 to 15 cm), deep organic (15 to 35 cm), and mineral soil layers (35 to 55 cm) separately by means of stable isotope analysis (δ13C and δ15N) and solid-state 13C nuclear magnetic resonance. Compared to the control, the experimental warming did not affect the isotopic and molecular composition of soil organic matter across the depth profile. However, we did find significant changes with time. In particular, in the surface organic layer, δ13C decreased and alkyl/O-alkyl ratio increased from 2009 to 2013, which indicated variations in soil organic sources (e.g., changes in vegetation) and accelerated decomposition. In the deep organic layer, we found a slight increase in δ15N with time. In the mineral layer, δ13C values decreased slightly, whereas alkyl C/O-alkyl ratio increased, suggesting a preferential loss of relatively more degraded organic matter fractions probably by lateral transport by water flowing through the soil. Acknowledgements: This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 654132. Web site: http://vulcan.comule.com

  14. Organic matter decomposition in simulated aquaculture ponds

    NARCIS (Netherlands)

    Torres Beristain, B.

    2005-01-01

    Different kinds of organic and inorganic compounds (e.g. formulated food, manures, fertilizers) are added to aquaculture ponds to increase fish production. However, a large part of these inputs are not utilized by the fish and are decomposed inside the pond. The microbiological decomposition of the

  15. Insights into the nature of cometary organic matter from terrestrial analogues

    Science.gov (United States)

    Court, Richard W.; Sephton, Mark A.

    2012-04-01

    The nature of cometary organic matter is of great interest to investigations involving the formation and distribution of organic matter relevant to the origin of life. We have used pyrolysis-Fourier transform infrared (FTIR) spectroscopy to investigate the chemical effects of the irradiation of naturally occurring bitumens, and to relate their products of pyrolysis to their parent assemblages. The information acquired has then been applied to the complex organic matter present in cometary nuclei and comae. Amalgamating the FTIR data presented here with data from published studies enables the inference of other comprehensive trends within hydrocarbon mixtures as they are progressively irradiated in a cometary environment, namely the polymerization of lower molecular weight compounds; an increased abundance of polycyclic aromatic hydrocarbon structures; enrichment in 13C; reduction in atomic H/C ratio; elevation of atomic O/C ratio and increase in the temperature required for thermal degradation. The dark carbonaceous surface of a cometary nucleus will display extreme levels of these features, relative to the nucleus interior, while material in the coma will reflect the degree of irradiation experienced by its source location in the nucleus. Cometary comae with high methane/water ratios indicate a nucleus enriched in methane, favouring the formation of complex organic matter via radiation-induced polymerization of simple precursors. In contrast, production of complex organic matter is hindered in a nucleus possessing a low methane/water ration, with the complex organic matter that does form possessing more oxygen-containing species, such as alcohol, carbonyl and carboxylic acid functional groups, resulting from reactions with hydroxyl radicals formed by the radiolysis of the more abundant water. These insights into the properties of complex cometary organic matter should be of particular interest to both remote observation and space missions involving in situ

  16. Laboratory Calibration Studies in Support of ORGANICS on the International Space Station: Evolution of Organic Matter in Space

    Science.gov (United States)

    Ruiterkamp, R.; Ehrenfreund, P.; Halasinski, T.; Salama, F.; Foing, B.; Schmidt, W.

    2002-01-01

    This paper describes the scientific overview and current status of ORGANICS an exposure experiment performed on the International Space Station (ISS) to study the evolution of organic matter in space (PI: P. Ehrenfreund), with supporting laboratory experiments performed at NASA Ames. ORGANICS investigates the chemical evolution of samples submitted to long-duration exposure to space environment in near-Earth orbit. This experiment will provide information on the nature, evolution, and survival of carbon species in the interstellar medium (ISM) and in solar system targets.

  17. Freshwater processing of terrestrial dissolved organic matter: What governs lability?

    Science.gov (United States)

    D'Andrilli, J.; Smith, H. J.; Junker, J. R.; Scholl, E. A.; Foreman, C. M.

    2016-12-01

    Aquatic and terrestrial ecosystems are linked through the transfer of energy and materials. Allochthonous organic matter (OM) is central to freshwater ecosystem function, influencing local food webs, trophic state, and nutrient availability. In order to understand the nature and fate of OM from inland headwaters to the open ocean, it is imperative to understand the links between OM lability and ecosystem function. Thus, biological, chemical, and physical factors need to be evaluated together to inform our understanding of environmental lability. We performed a laboratory processing experiment on naturally occurring OM leachates from riparian leaves, grasses, and pine needles. Measures of water chemistry, OM optical and molecular characterization, bacterial abundances, microbial assemblage composition, respiration, and C:N:P were integrated to discern the nature and fate of labile and recalcitrant OM in a freshwater stream. Peak processing of all OM sources in the stream water occurred after two days, with spikes in bacterial cell abundances, respiration rates, microbial assemblage shifts, and maximum C utilization. Respiration rates and microbial assemblages were dependent on the degree of lability of the OM molecular composition. Within the first few days, no differences in respiration rates were observed between leachate sources, however, beyond day five, the rates diverged with C processing efficiency correlated with OM lability. Originally comprised of amino acid-like, labile fluorescent species, the inoculated stream water OM became more recalcitrant after 16 days, indicating humification processing over time. Our study highlights the importance of interdisciplinary approaches for understanding the processing and fate of OM in aquatic ecosystems.

  18. Mercury reduction and complexation by natural organic matter

    International Nuclear Information System (INIS)

    Gu, Baohua; Bian, Yongrong; Miller, Carrie L.; Dong, Wenming; Jiang, Xin; Liang, Liyuan

    2011-01-01

    Mercuric Hg(II) species form complexes with natural dissolved organic matter (DOM) such as humic acid (HA), and this binding is known to affect the chemical and biological transformation and cycling of mercury in aquatic environments. Dissolved elemental mercury, Hg(0), is also widely observed in sediments and water. However, reactions between Hg(0) and DOM have rarely been studied in anoxic environments. Here, under anoxic dark conditions we show strong interactions between reduced HA and Hg(0) through thiol-ligand induced oxidative complexation with an estimated binding capacity of about 3.5 umol Hg(0)/g HA and a partitioning coefficient greater than 10 6 mL/g. We further demonstrate that Hg(II) can be effectively reduced to Hg(0) in the presence of as little as 0.2 mg/L reduced HA, whereas production of purgeable Hg(0) is inhibited by complexation as HA concentration increases. This dual role played by DOM in the reduction and complexation of mercury is likely widespread in anoxic sediments and water and can be expected to significantly influence the mercury species transformations and biological uptake that leads to the formation of toxic methylmercury.

  19. Natural organic matter and the event horizon of mass spectrometry.

    Science.gov (United States)

    Hertkorn, N; Frommberger, M; Witt, M; Koch, B P; Schmitt-Kopplin, Ph; Perdue, E M

    2008-12-01

    Soils, sediments, freshwaters, and marine waters contain natural organic matter (NOM), an exceedingly complex mixture of organic compounds that collectively exhibit a nearly continuous range of properties (size-reactivity continuum). NOM is composed mainly of carbon, hydrogen, and oxygen, with minor contributions from heteroatoms such as nitrogen, sulfur, and phosphorus. Suwannee River fulvic acid (SuwFA) is a fraction of NOM that is relatively depleted in heteroatoms. Ultrahigh resolution Fourier transform ion cyclotron (FTICR) mass spectra of SuwFA reveal several thousand molecular formulas, corresponding in turn to several hundred thousand distinct chemical environments of carbon even without accountancy of isomers. The mass difference deltam among adjoining C,H,O-molecules between and within clusters of nominal mass is inversely related to molecular dissimilarity: any decrease of deltam imposes an ever growing mandatory difference in molecular composition. Molecular formulas that are expected for likely biochemical precursor molecules are notably absent from these spectra, indicating that SuwFA is the product of diagenetic reactions that have altered the major components of biomass beyond the point of recognition. The degree of complexity of SuwFA can be brought into sharp focus through comparison with the theoretical limits of chemical complexity, as constrained and quantized by the fundamentals of chemical binding. The theoretical C,H,O-compositional space denotes the isomer-filtered complement of the entire, very vast space of molecular structures composed solely of carbon, hydrogen, and oxygen. The molecular formulas within SuwFA occupy a sizable proportion of the theoretical C,H,O-compositional space. A 100 percent coverage of the theoretically feasible C,H,O-compositional space by SuwFA molecules is attained throughout a sizable range of mass and H/C and O/C elemental ratios. The substantial differences between (and complementarity of) the SuwFA molecular

  20. Securing decommissioning funds. Why organization matters?

    International Nuclear Information System (INIS)

    Tchapga, F.

    2005-01-01

    Full text: Securing decommissioning funds requires that the financial resources set aside for the purpose of decommissioning be managed prudently. Decommissioning of nuclear power plant is prescribed by National Atomic Laws or by other nuclear legislation. It is a mandatory operation. The operators of nuclear power plants set money aside for that purpose. This is known as 'Decommissioning reserve fund'. Decommissioning implies costs very distant in time. Thus, it is obvious, from an economic point of view, that the funds set aside should be managed. As decommissioning is mandatory, the funds accumulated should be secured. In others words, they should be available when needed. Availability of funds is influenced by endogenous and exogenous factors. Endogenous factors are a matter of design of the reserve funds. They include the management of the funds, its monitoring and control... Availability of funds is influenced by these factors, depending on the rules to which the behaviour of the manager of the funds is subjected. In contrast, exogenous factors deal with the energy context. These factors are mainly the electricity sector organisation and/or the overall economic situation. They are decisive factors of the economic performance of the reserve fund for a given design. Therefore, the requirement of availability of funds, when needed, is a matter of compatibility between the design of the decommissioning funds and the electricity context. Put differently, reserve fund's design need to be consistent with the electricity context's features in respect of the availability of funds. Current reserve funds were designed in a context of monopoly regime. In this context, availability of decommissioning funds was not questionable. At least, as far as the design of the reserve funds is concerned. This is because nuclear generator didn't confront any competition pressure. Electricity prices were set trough rate base mechanism, and all the business risks were borne by the

  1. Detection of organic matter in interstellar grains.

    Science.gov (United States)

    Pendleton, Y J

    1997-06-01

    Star formation and the subsequent evolution of planetary systems occurs in dense molecular clouds, which are comprised, in part, of interstellar dust grains gathered from the diffuse interstellar medium (DISM). Radio observations of the interstellar medium reveal the presence of organic molecules in the gas phase and infrared observational studies provide details concerning the solid-state features in dust grains. In particular, a series of absorption bands have been observed near 3.4 microns (approximately 2940 cm-1) towards bright infrared objects which are seen through large column densities of interstellar dust. Comparisons of organic residues, produced under a variety of laboratory conditions, to the diffuse interstellar medium observations have shown that aliphatic hydrocarbon grains are responsible for the spectral absorption features observed near 3.4 microns (approximately 2940 cm-1). These hydrocarbons appear to carry the -CH2- and -CH3 functional groups in the abundance ratio CH2/CH3 approximately 2.5, and the amount of carbon tied up in this component is greater than 4% of the cosmic carbon available. On a galactic scale, the strength of the 3.4 microns band does not scale linearly with visual extinction, but instead increases more rapidly for objects near the Galactic Center. A similar trend is noted in the strength of the Si-O absorption band near 9.7 microns. The similar behavior of the C-H and Si-O stretching bands suggests that these two components may be coupled, perhaps in the form of grains with silicate cores and refractory organic mantles. The ubiquity of the hydrocarbon features seen in the near infrared near 3.4 microns throughout out Galaxy and in other galaxies demonstrates the widespread availability of such material for incorporation into the many newly forming planetary systems. The similarity of the 3.4 microns features in any organic material with aliphatic hydrocarbons underscores the need for complete astronomical observational

  2. Effects of effluent organic matter characteristics on the removal of bulk organic matter and selected pharmaceutically active compounds during managed aquifer recharge: Column study

    KAUST Repository

    Maeng, Sungkyu; Sharma, Saroj K.; Abel, Chol D T; Magic-Knezev, Aleksandra; Song, Kyungguen; Amy, Gary L.

    2012-01-01

    Soil column experiments were conducted to investigate the effects of effluent organic matter (EfOM) characteristics on the removal of bulk organic matter (OM) and pharmaceutically active compounds (PhACs) during managed aquifer recharge (MAR

  3. Origins and bioavailability of dissolved organic matter in groundwater

    Science.gov (United States)

    Shen, Yuan; Chapelle, Francis H.; Strom, Eric W.; Benner, Ronald

    2015-01-01

    Dissolved organic matter (DOM) in groundwater influences water quality and fuels microbial metabolism, but its origins, bioavailability and chemical composition are poorly understood. The origins and concentrations of dissolved organic carbon (DOC) and bioavailable DOM were monitored during a long-term (2-year) study of groundwater in a fractured-rock aquifer in the Carolina slate belt. Surface precipitation was significantly correlated with groundwater concentrations of DOC, bioavailable DOM and chromophoric DOM, indicating strong hydrological connections between surface and ground waters. The physicochemical and biological processes shaping the concentrations and compositions of DOM during its passage through the soil column to the saturated zone are conceptualized in the regional chromatography model. The model provides a framework for linking hydrology with the processes affecting the transformation, remineralization and microbial production of DOM during passage through the soil column. Lignin-derived phenols were relatively depleted in groundwater DOM indicating substantial removal in the unsaturated zone, and optical properties of chromophoric DOM indicated lower molecular weight DOM in groundwater relative to surface water. The prevalence of glycine, γ-aminobutyric acid, and d-enantiomers of amino acids indicated the DOM was highly diagenetically altered. Bioassay experiments were used to establish DOC-normalized yields of amino acids as molecular indicators of DOM bioavailability in groundwater. A relatively small fraction (8 ± 4 %) of DOC in groundwater was bioavailable. The relatively high yields of specific d-enantiomers of amino acids indicated a substantial fraction (15–34 %) of groundwater DOC was of bacterial origin.

  4. Separating the effects of organic matter-mineral interactions and organic matter chemistry on the sorption of diuron and phenanthrene.

    Science.gov (United States)

    Ahangar, Ahmad Gholamalizadeh; Smernik, Ronald J; Kookana, Rai S; Chittleborough, David J

    2008-06-01

    Even though it is well established that soil C content is the primary determinant of the sorption affinity of soils for non-ionic compounds, it is also clear that organic carbon-normalized sorption coefficients (K(OC)) vary considerably between soils. Two factors that may contribute to K(OC) variability are variations in organic matter chemistry between soils and interactions between organic matter and soil minerals. Here, we quantify these effects for two non-ionic sorbates-diuron and phenanthrene. The effect of organic matter-mineral interactions were evaluated by comparing K(OC) for demineralized (HF-treated) soils, with K(OC) for the corresponding whole soils. For diuron and phenanthrene, average ratios of K(OC) of the HF-treated soils to K(OC) of the whole soils were 2.5 and 2.3, respectively, indicating a substantial depression of K(OC) due to the presence of minerals in the whole soils. The effect of organic matter chemistry was determined by correlating K(OC) against distributions of C types determined using solid-state (13)C NMR spectroscopy. For diuron, K(OC) was positively correlated with aryl C and negatively correlated with O-alkyl C, for both whole and HF-treated soils, whereas for phenanthrene, these correlations were only present for the HF-treated soils. We suggest that the lack of a clear effect of organic matter chemistry on whole soil K(OC) for phenanthrene is due to an over-riding influence of organic matter-mineral interactions in this case. This hypothesis is supported by a correlation between the increase in K(OC) on HF-treatment and the soil clay content for phenanthrene, but not for diuron.

  5. TMVOC, simulator for multiple volatile organic chemicals

    International Nuclear Information System (INIS)

    Pruess, Karsten; Battistelli, Alfredo

    2003-01-01

    TMVOC is a numerical simulator for three-phase non-isothermal flow of water, soil gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous media. It is an extension of the TOUGH2 general-purpose simulation program developed at the Lawrence Berkeley National Laboratory. TMVOC is designed for applications to contamination problems that involve hydrocarbon fuel or organic solvent spills in saturated and unsaturated zones. It can model contaminant behavior under ''natural'' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. TMVOC is upwards compatible with T2VOC (Falta et al., 1995) and can be initialized from T2VOC-style initial conditions. The main enhancements in TMVOC relative to T2VOC are as follows: a multicomponent mixture of volatile organic chemicals can be modeled; any and all combinations of the three phases water-oil-gas are treated; several non-condensible gases may be present; diffusion is treated in all phases in a manner that is fully coupled with phase partitioning. This paper gives a brief summary of the methodology used in TMVOC as well as highlighting some implementation issues. Simulation of a NAPL spill and subsequent remediation is discussed for a 2-D vertical section of a saturated-unsaturated flow problem

  6. Assessment of the unidentified organic matter fraction in fogwater using fluorescence spectroscopy

    Science.gov (United States)

    Valsaraj, K.; Birdwell, J.

    2010-07-01

    Dissolved organic matter (DOM) in fogwaters from southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix (EEM) fluorescence spectroscopy. The results demonstrate that fluorescence spectroscopy can be used to obtain a qualitative assessment of the large fraction of fogwater organic carbon (~40 - 80% by weight) that cannot be identified in terms of specific chemical compounds. The method has the principle advantage that it can be applied at natural abundance concentrations, thus eliminating the need for large sample volumes required to isolate DOM for characterization by other spectroscopic (NMR, FTIR) and chemical (elemental) analyses. It was anticipated that the fogwater organic matter fluorescence spectra would resemble those of surface and rain waters, containing peaks indicative of both humic substances and fluorescent amino acids. Humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices had values comparable to other natural waters. Biological character (intensity of tyrosine and tryptophan peaks) was found to increase with organic carbon concentration. Fogwater organic matter appears to contain a mixture of terrestrially- and microbially-derived material. The fluorescence results show that most of the unidentified fogwater organic carbon can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems.

  7. Assessing the stability of soil organic matter by fractionation and 13C isotope techniques

    Science.gov (United States)

    Larionova, A. A.; Zolotareva, B. N.; Kvitkina, A. K.; Evdokimov, I. V.; Bykhovets, S. S.; Stulin, A. F.; Kuzyakov, Ya. V.; Kudeyarov, V. N.

    2015-02-01

    Carbon pools of different stabilities have been separated from the soil organic matter of agrochernozem and agrogray soil samples. The work has been based on the studies of the natural abundance of the carbon isotope composition by C3-C4 transition using the biokinetic, size-density, and chemical fractionation (6 M HCl hydrolysis) methods. The most stable pools with the minimum content of new carbon have been identified by particle-size and chemical fractionation. The content of carbon in the fine fractions has been found to be close to that in the nonhydrolyzable residue. This pool makes up 65 and 48% of Corg in the agrochernozems and agrogray soils, respectively. The combination of the biokinetic approach with particle-size fractionation or 6 M HCl hydrolysis has allowed assessing the size of the medium-stable organic carbon pool with a turnover time of several years to several decades. The organic matter pool with this turnover rate is usually identified from the variation in the 13C abundance by C3-C4 transition. In the agrochernozems and agrogray soils, the medium-stable carbon pool makes up 35 and 46% of Corg, respectively. The isotope indication may be replaced by a nonisotope method to significantly expand the study of the inert and mediumstable organic matter pools in the geographical aspect, but this requires a comparative analysis of particle-size and chemical fractionation data for all Russian soils.

  8. Relationship between Mineral and Organic Matter in Shales: The Case of Shahejie Formation, Dongying Sag, China

    Directory of Open Access Journals (Sweden)

    Xiang Zeng

    2018-05-01

    Full Text Available Types of organic matter and mineral associations and microstructures of shales can reflect the depositional mechanism and sedimentary environment. Therefore, analysis of organic matter and mineral associations is a prerequisite for research on fine-grained sedimentary rocks. Shales from the Eocene Shahejie Formation in the Dongying Sag of China were selected to classify their lithofacies and to investigate the characteristics of their organic matter and mineral associations. This analysis identified six lithofacies (e.g., laminated shales and massive mudstones; in all the lithofacies, clay minerals exhibit a positive correlation with detrital minerals, thus indicating that they were derived from the same source. The comprehensive analysis of mineral and organic matter associations reveals that detrital minerals were deposited with low-hydrogen index (HI OM. The deposition of detrital minerals was mainly a physical process. Clay minerals can undergo deposition in one of two ways due to their surface charge: they can either aggregate with high-HI OM via chemical deposition, thus forming organic-rich laminae, or they can be deposited together with low-HI OM via physical deposition, thus forming clay-rich laminae or a massive matrix. Carbonate minerals, which often coexist with high-HI OM, are biological sediments. The analysis of the sedimentary characteristics of these organic matter and mineral associations indicates that the sedimentary processes differ between various lithofacies: e.g., the discontinuous laminated shale represents the product of biophysical processes. Differences in depositional mechanisms are also present in each sub-member. Therefore, it is important to analyze the properties of minerals and organic matter, as well as their associations, to more deeply understand the classification of lithofacies and the depositional processes of shales and mudstones.

  9. Stabilization of ancient organic matter in deep buried paleosols

    Science.gov (United States)

    Marin-Spiotta, E.; Chaopricha, N. T.; Mueller, C.; Diefendorf, A. F.; Plante, A. F.; Grandy, S.; Mason, J. A.

    2012-12-01

    Buried soils representing ancient surface horizons can contain large organic carbon reservoirs that may interact with the atmosphere if exposed by erosion, road construction, or strip mining. Paleosols in long-term depositional sites provide a unique opportunity for studying the importance of different mechanisms on the persistence of organic matter (OM) over millennial time-scales. We report on the chemistry and bioavailability of OM stored in the Brady soil, a deeply buried (7 m) paleosol in loess deposits of southwestern Nebraska, USA. The Brady Soil developed 9,000-13,500 years ago during a time of warming and drying. The Brady soil represents a dark brown horizon enriched in C relative to loess immediately above and below. Spanning much of the central Great Plains, this buried soil contains large C stocks due to the thickness of its A horizon (0.5 to 1 m) and wide geographic extent. Our research provides a unique perspective on long-term OM stabilization in deep soils using multiple analytical approaches. Soils were collected from the Brady soil A horizon (at 7 m depth) and modern surface A horizons (0-15 cm) at two sites for comparison. Soils were separated by density fractionation using 1.85 g ml-1 sodium polytungstate into: free particulate organic matter (fPOM) and aggregate-occluded (oPOM) of two size classes (large: >20 μm, and small: separated into sand, silt, and clay size fractions. The distribution and age of C among density and particle-size fractions differed between surface and Brady soils. We isolated the source of the characteristic dark coloring of the Brady soil to the oPOM-small fraction, which also contained 20% of the total organic C pool in the Brady soil. The oPOM-small fraction and the bulk soil in the middle of the Brady A horizon had 14C ages of 10,500-12,400 cal yr BP, within the time that the soil was actively forming at the land surface. Surface soils showed modern ages. Lipid analyses of the Brady soil indicate a predominance of

  10. Energy Transformations of Soil Organic Matter in a Changing World

    Science.gov (United States)

    Herrmann, A. M.; Coucheney, E.; Grice, S. M.; Ritz, K.; Harris, J.

    2011-12-01

    The role of soils in governing the terrestrial carbon balance is acknowledged as being important but remains poorly understood within the context of climate change. Soils exchange energy with their surroundings and are therefore open systems thermodynamically, but little is known how energy transformations of decomposition processes are affected by temperature. Soil organic matter and the soil biomass can be conceptualised as analogous to the 'fuel' and 'biological engine' of the earth, respectively, and are pivotal in driving the belowground carbon cycle. Thermodynamic principles of soil organic matter decomposition were evaluated by means of isothermal microcalorimetry (TAM Air, TA Instruments, Sollentuna Sweden: (i) Mineral forest soils from the Flakaliden long-term nitrogen fertilisation experiment (Sweden) were amended with a range of different substrates representing structurally simple to complex, ecologically pertinent organic matter and heat signatures were determined at temperatures between 5 and 25°C. (ii) Thermodynamic and resource-use efficiencies of the biomass were determined in arable soils which received contrasting long-term management regimes with respect to organic matter and nitrogen since 1956. The work showed that (i) structurally labile components have higher activation energy and temperature dependence than structurally more complex organic components. This is, however, in contrast to the thermodynamic argument which suggests the opposite that reactions metabolising structurally complex, aromatic components have higher temperature dependence than reactions metabolising structurally more labile components. (ii) Microbial communities exposed to long-term stress by heavy metal and low pH were less thermodynamic efficient and showed a decrease in resource-use efficiency in comparison with conventional input regimes. Differences in efficiencies were mirrored in both the phenotypic and functional profiles of the communities. We will present our

  11. Influence of organic matter on the solubility of ThO2 and geochemical modeling

    International Nuclear Information System (INIS)

    Liu Dejun; Luo Tian; Maes, N.; Bruggeman, C.

    2014-01-01

    Thorium (IV) is widely considered in laboratory experiments as a suitable chemical analogue for long-lived tetravalent actinides. Th (IV) is redox-insensitive, as an analogue for U (IV) to study the influence of natural organic matter on the solubility. The solubility of crystalline ThO 2 (cr) has been measured under geochemical conditions representative for the Boom Clay using Real Boom Clay Water containing organic matter to assess its influence on the ThO 2 (cr) solubility. For the purpose of comparison, Aldrich Humic Acid was also investigated. Solubility measurements of ThO 2 (cr) were approached from under-saturation in an anaerobic glove box with a controlled Ar0.4%CO 2 atmosphere. Th concentration is determined after 30000 MWCO, 300000 MWCO, and 0.45 μm filtration to distinguish solid (0.45 μm), larger colloids (300000 MWCO), and small dissolved species(30000 MWCO). X-ray diffraction was carried out to investigate the transformation of ThO 2 (cr) phase during the contact with Boom Clay Water. In Synthetic Boom Clay Water (without organic matter) the concentrations of Th (IV) are 5 × l0 -ll mol/L, 4 × lO -10 mol/L, and 8 × lO -8 mol/L after 30000 MWCO, 300000 MWCO, and 0. 45 μm filtration, respectively. It indicated the existence of inorganic colloids in solution. The increase of the total Th solution concentration with increasing organic matter concentration revealed a complexation-like interaction between Th and organic matter. All the experimental data could be modeled by Tipping humic ion-binding model VI using a combination of solubility calculations and complexation reactions between Th (IV) and organic matter functional groups. Similar to the investigation of Eu 3+ solubility, the affinity of organic matter for Th was higher for Aldrich humic acid compared to Boom Clay organic matter. However, Boom Clay organic matter with different size had the similar complexation affinity with Th (IV). (authors)

  12. Vertical transport of organic matter in the various oceanic areas

    International Nuclear Information System (INIS)

    Handa, Nobuhiko; Hayakawa, Kazuhide

    1993-01-01

    Organic matter produced by the photosynthesis of the phytoplankton is removed from the euphotic layer to the underlying waters by sinking of the particles consisting of both marine snow and fecal pellet. Phytoplankton bloom always enhances the vertical flux of organic matter from the subsurface to deep waters. Turbidity current is another factor to govern the vertical flux of organic carbon especially in the continental shelf to its slope areas. However, no information are available to distinguish the organic materials from these two sources. Stable carbon isotope ratio and fatty acid composition give most promising informations to diagnose the physiological state of the phytoplankton which is one of the source of the organic materials of the sinking particle, because of the extensive variations of the δ 13 C of the phytoplankton cellular organic matter and fatty acid composition due to the phytoplankton growth rate (O'Leary, 1981; Morris et al., 1985). Δ 14 C of the organic matter of the sinking particle will provide an information as to how much organic materials are derived from the phytoplankton growing in the surface and subsurface waters and/or from the resuspended particles of the surface sediment in the continental shelf and its slope areas. Recently we analyzed various samples of the sinking particles collected from the coastal areas of the Antarctica and off Hokkaido, Japan for fatty acids and found that ratios as biomarker to diagnose these growth phases of the phytoplankton growing in the surface to subsurface waters. Thus, we intend to report here these data obtained. (J.P.N.)

  13. Elimination kinetic model for organic chemicals in earthworms.

    NARCIS (Netherlands)

    Dimitrova, N.; Dimitrov, S.; Georgieva, D.; van Gestel, C.A.M.; Hankard, P.; Spurgeon, D.J.; Li, H.; Mekenyan, O.

    2010-01-01

    Mechanistic understanding of bioaccumulation in different organisms and environments should take into account the influence of organism and chemical depending factors on the uptake and elimination kinetics of chemicals. Lipophilicity, metabolism, sorption (bioavailability) and biodegradation of

  14. Selective depletion of organic matter in mottled podzol horizons

    NARCIS (Netherlands)

    Buurman, P.; Schellekens, J.; Fritze, H.; Nierop, K.G.J.

    2007-01-01

    Abstract: Some well-drained podzols on quartz sands in the Netherlands and neighbouring Belgium and Germany show mottling in all horizons due to selective removal of organic matter. Phospholipid analysis and morphology of the mottles suggests that this removal is due to activity of fungi.

  15. Selective depletion of organic matter in mottled podzol horizons

    NARCIS (Netherlands)

    Buurman, P.; Schellekens, J.F.P.; Fritze, H.; Nierop, K.G.J.

    2007-01-01

    Some well-drained podzols on quartz sands in the Netherlands and neighbouring Belgium and Germany show mottling in all horizons due to selective removal of organic matter. Phospholipid analysis and morphology of the mottles suggests that this removal is due to a combination of bacteria, fungi, and

  16. Fluorescent dissolved organic matter in the continental shelf waters ...

    Indian Academy of Sciences (India)

    Fluorescent dissolved organic matter (FDOM) of southwestern Bay of Bengal surface water during southwest monsoon consisted five fluorophores, three humic-like and two protein-like. The humification index (HIX) and humic fluorophores, viz., visible (C), marine (M) and UV (A) humic-likes indicated, better than ...

  17. Lyophilization and Reconstitution of Reverse Osmosis Concentrated Natural Organic Matter

    Science.gov (United States)

    Disinfection by-product (DBP) research can be complicated by difficulties in shipping large water quantities and changing natural organic matter (NOM) characteristics over time. To overcome these issues, it is advantageous to have a reliable method for concentrating and preservin...

  18. Natural organic matter (NOM) in South African waters: NOM ...

    African Journals Online (AJOL)

    In order to remove natural organic matter (NOM) from water in a water treatment train, the composition of the NOM in the source water must be taken into account, especially as it may not necessarily be uniform since the composition is dependent on the local environment. The main thrust of this study was to ascertain ...

  19. Light fraction of soil organic matter under different management ...

    African Journals Online (AJOL)

    A study on light fraction organic matter was carried out on the soil from three different management systems namely; Gmelina arborea, Tectona grandis and Leucaena leucocephala plantations in the University of Agriculture, Abeokuta Nigeria. Soil samples were collected in each of the three management site at five auger ...

  20. Soil organic matter reduces the sorption of arsenate and phosphate

    NARCIS (Netherlands)

    Verbeeck, M.; Hiemstra, T.; Thiry, Y.; Smolders, E.

    2017-01-01

    The arsenate (AsO4) and phosphate (PO4) mobility in aerobic soil is affected by soil organic matter (OM). This study was set up to quantify the interaction between OM and AsO4 with an observational, experimental and computational approach. The adsorption of

  1. Degradation Mechanisms of Colloidal Organic Matter in Biofilm Reactors

    DEFF Research Database (Denmark)

    Larsen, Tove; Harremoës, Poul

    1994-01-01

    -diffusible organic matter in a biofilm reactor. DH depends on the combined volumetric and surface hydraulic loading rate, Q2/(AV). In full-scale wastewater treatment plants, the degradation mechanism presented in this paper can explain important differences between the performance of trickling filters and RBC...

  2. Reactivity of Organic Matter and other Reductants in Aquifer Sediments

    NARCIS (Netherlands)

    Hartog, N.

    2003-01-01

    The molecular composition and the carbon isotope signature of sedimentary organic matter (SOM) and indicate that SOM is predominantly derived from higher land plants in sediments of both terrestrial as marine origins. The reactivity of SOM in the aquifer sediments studied is determined by the extent

  3. Non-pharmacological modulation of cerebral white matter organization

    DEFF Research Database (Denmark)

    Kristensen, Tina D; Mandl, Rene C W; Jepsen, Jens R M

    2018-01-01

    OBJECTIVE: Neuroplasticity is a well-described phenomenon, but effects of non-pharmacological interventions on white matter (WM) are unclear. Here we review associations between active non-pharmacological interventions and WM organization in healthy subjects and in psychiatric patients. METHOD...

  4. Effect of four herbicides on microbial population, soil organic matter ...

    African Journals Online (AJOL)

    The effect of four herbicides (atrazine, primeextra, paraquat and glyphosate) on soil microbial population, soil organic matter and dehydrogenase activity was assessed over a period of six weeks. Soil samples from cassava farms were treated with herbicides at company recommended rates. Soil dehydrogenase activity was ...

  5. SOMPROF: A vertically explicit soil organic matter model

    NARCIS (Netherlands)

    Braakhekke, M.C.; Beer, M.; Hoosbeek, M.R.; Kruijt, B.; Kabat, P.

    2011-01-01

    Most current soil organic matter (SOM) models represent the soil as a bulk without specification of the vertical distribution of SOM in the soil profile. However, the vertical SOM profile may be of great importance for soil carbon cycling, both on short (hours to years) time scale, due to

  6. Degradation of riverine dissolved organic matter by seawater bacteria

    NARCIS (Netherlands)

    Rochelle-Newall, E.J.; Pizay, M-D.; Middelburg, J.J.; Boschker, H.T.S.; Gattuso, J.P.

    2004-01-01

    The functional response of a seawater bacterial community transplanted into freshwater dissolved organic matter (DOM) was investigated together with the response of natural populations of bacteria to size-fractioned natural source water. Seawater bacteria were incubated over a period of 8 d in

  7. Organic richness and organic matter quality studies of source rocks ...

    African Journals Online (AJOL)

    The hydrocarbon potential of the Upper Cretaceous units (Maastrichtian Mamu Formation) exposed at Imiegba and environs of the Benin Flank, Western Anambra Basin was assessed by Total Organic Carbon (TOC) and Rock-Eval Pyrolysis Analyses. The investigated sections of the Mamu Formation consist of dark grey to ...

  8. Unraveling the size-dependent optical properties of dissolved organic matter

    DEFF Research Database (Denmark)

    Wünsch, Urban; Stedmon, Colin; Tranvik, Lars

    2018-01-01

    The size-dependent optical properties of dissolved organic matter (DOM) from four Swedish lakes were investigated using High Performance Size Exclusion Chromatography (HPSEC) in conjunction with online characterization of absorbance (240–600 nm) and fluorescence (excitation: 275 nm, emission: 300....... This study demonstrates the potential for HPSEC and novel mathematical approaches to provide unprecedented insights into the relationship between optical and chemical properties of DOM in aquatic systems...

  9. Soil erosion and organic matter loss by using fallout 137Cs as tracer in Miyun reservoir valley

    International Nuclear Information System (INIS)

    Hua Luo; Zhang Zhigang; Li Junbo; Feng Yan; Zhao Hong; Yin Xunxiao; Zhu Fengyun

    2005-01-01

    Miyun reservoir is one of the important water sources for Beijing, the water quality of the reservoir is directly influenced by soil erosion. Based on measuring the 137 Cs concentrations, organic content in the soil of selected sampling sites, the authors investigated the relationship between the quality of soil erosion and organic matters. According to classificatory standards of soil erosion, the intensity of erosion in Miyun reservoir valley is light and moderate, but in some parts erosion is serious. The land use model has dramatic influence on distribution of organic matters in the soil. Unreasonable human activities could cause serious increase of organic matter runoff and soil erosion intensity. Distributions of organic matters were increased in the following order: bush land > forestry > orchard > farmland. Organic matters in the upper course were higher than in the circumference of reservoir. The simulated model suggests that there is a cubic relation between the contents of organic matters and 137 Cs concentrations (r 2 =0.9). The math model in the single sights can forecast soil erosion and changes of concentrations of organic matters in the soils, so that the chemical analysis and measurements are simplified. (authors)

  10. Speciation and Distribution of Trace Metals and Organic Matter in Marine Lake as In Situ Laboratory

    Science.gov (United States)

    Mlakar, M.; Fiket, Ž.; Cuculić, V.; Cukrov, N.; Geček, S.

    2016-02-01

    Marine lakes are unique, isolated marine systems, also recognized as in situ "laboratories" in which geochemical processes on a different scale compared to the open sea, can be observed. Impact of organic matter cycling on distribution of trace metals in the marine lake Mir, located on Dugi Otok Island, in the central part of the eastern Adriatic Sea, was investigated. Intense spatial and seasonal variations of physico-chemical parameters and organic matter concentrations in the water column of the Lake are governed predominantly by natural processes. Enhanced oxygen consumption in the Lake during summer season, high organic carbon concentrations and low redox potential result in occasional occurrence of anoxic conditions in the bottom layers. Speciation modelling showed that dissolved trace metals Cu, Pb and Zn, are mostly bound to organic matter, while Cd, Co and Ni are present predominantly as free ions and inorganic complexes. Trace metals removal from the water column and their retention in the sediment was found to depend on the nature of the relationship between specific metal and high proportion of organic matter (up to 9%) and inorganic phases, Fe-oxyhydroxydes or biogenic calcite. Surrounding karstic background, with occasional occurrences of red soil characterize deposited sediments as coarse grained and carbonate rich, whose elemental composition is affected by bathymetry of the basin and overall biological production.

  11. Roles of epi-anecic taxa of earthworms in the organic matter recycling

    Science.gov (United States)

    Hoeffner, Kevin; Monard, Cécile; Santonja, Mathieu; Pérès, Guénola; Cluzeau, Daniel

    2017-04-01

    Given their impact on soil functioning and their interactions with soil organisms, earthworms contribute to the recycling of organic matter and participate significantly in the numerous ecosystem services provided by soils. Most studies on the role of earthworms in organic matter recycling were conducted at the level of the four functional groups (epigeic, epi-anecic, anecic strict and endogeic), but their effects at taxa level remain largely unknown. Still, within a functional group, anatomic and physiologic earthworm taxa traits are different, which should impact organic matter recycling. This study aims at determining, under controlled conditions, epi-anecic taxa differences in (i) leaf litter mass loss, (ii) assimilation and (iii) impact on microorganisms communities implied in organic matter degradation. In seperate microcosms, we chose 4 epi anecic taxa (Lumbricus rubellus, Lumbricus festivus, Lumbricus centralis and Lumbricus terrestris). Each taxon was exposed separately to leaves of three different plants (Holcus lanatus, Lolium perenne and Corylus avellana). In the same microcosm, leaves of each plant was both placed on the surface and buried 10cm deep. The experiment lasted 10 days for half of the samples and 20 days for the second half. Microorganisms communities were analysed using TRFLP in each earthworm taxon burrow walls at 20 days. We observed differences between epi-anecic taxa depending on species of plant and the duration of the experiment. Results are discussed taking into account physical and chemical properties of these 3 trophic resources (e.g. C/N ratio, phenolic compounds, percentage of lignin and cellulose...).

  12. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    Science.gov (United States)

    Chromophoric dissolved organic (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organic matter...

  13. Organic and Inorganic Matter in Louisiana Coastal Waters: Vermilion, Atchafalaya, Terrebonne, Barataria, and Mississippi Regions.

    Science.gov (United States)

    Chromophoric dissolved organic matter (CDOM) spectral absorption, dissolved organic carbon (DOC) concentration, and the particulate fraction of inorganic (PIM) and organic matter (POM) were measured in Louisiana coastal waters at Vermilion, Atchafalaya, Terrebonne, Barataria, and...

  14. Organic matter and the geotechnical properties of submarine sediments

    Science.gov (United States)

    Keller, George H.

    1982-09-01

    Continental slope deposits off Peru and Oregon where coastal upwelling is a pronounced oceanographic process possess significant concentrations of organic carbon. Geotechnical properties are altered to varying degrees by the organic matter. Organic matter absorbs water and causes clay-size particles to aggregate forming an open fabric. This causes unusually high water contents and plasticity and exceptionally low wet bulk densities. Some of these deposits show notable increases in shear strength, sensitivity and degree of apparent overconsolidation. Owing to the unique geotechnical properties, sediment stability characteristics are considered to be poor in situations of excess pore pressures. Failure appears to take the form of a fluidized flow somewhat similar to the quick clays of Scandinavia.

  15. Application of Remote Sensing for Mapping Soil Organic Matter Content

    Directory of Open Access Journals (Sweden)

    Bangun Muljo Sukojo

    2010-10-01

    Full Text Available Information organic content is important in monitoring and managing the environment as well as doing agricultural production activities. This research tried to map soil organic content in Malang using remote sensing technology. The research uses 6 bands of data captured by Landsat TM (Thematic Mapper satellite (band 1, 2, 3, 4, 5, 7. The research focuses on pixels having Normalized Difference Soil Index (NDSI more than 0.3. Ground-truth data were collected by analysing organic content of soil samples using Black-Walkey method. The result of analysis shows that digital number of original satellite image can be used to predict soil organic matter content. The implementation of regression equation in predicting soil organic content shows that 63.18% of research area contains of organic in a moderate category.

  16. Modeling the role of microplastics in Bioaccumulation of organic chemicals to marine aquatic organisms. Critical Review

    NARCIS (Netherlands)

    Koelmans, A.A.

    2015-01-01

    It has been shown that ingestion of microplastics may increase bioaccumulation of organic chemicals by aquatic organisms. This paper critically reviews the literature on the effects of plastic ingestion on the bioaccumulation of organic chemicals, emphasizing quantitative approaches and mechanistic

  17. Stabilization of organic matter in the raised-bed soils of tidal swamplands is influenced by the types and the amounts of organic matter application

    Directory of Open Access Journals (Sweden)

    A R Saidy

    2015-03-01

    Full Text Available Farmers in tidal swamplands annually added organic matter (OM onto the raised beds to maintain organic matter contents and thereby maintain soil productivity of the raised beds. This experiment aimed to study the influence of the types and the amounts of OM on the stabilization of organic matter in the raised-bed soils. Four types of OM: rice straw, eceng gondok (Eichornia crassipes, purun tikus  (Eleocharis dulcis and mixed  rice straw-eceng gondok were added to a 27-year raised bed soil with 4 different rates: 0, 0.5, 1.0 and 2.0  of maximum sorption capacity (Qmax, and the OM stabilization was quantified after 10 weeks of OM addition.  Results of this study showed with the exception of rice straw, OM addition to soil resulted in increases in the mineralization of soil OM thereby inducing priming effect. Addition of rice straw at rate of 0.5 of Qmax resulted in stabilization of 46% added OM, while only 30% and 37% of added OM was stabilized when OM was added to soils at rates of 1.0 and 2.0 Qmax, respectively.  This study showed that the stabilization of OM in raised bed soils were influenced by the chemical composition of OM and the amount of added OM.

  18. Stabilization of organic matter in the raised-bed soils of tidal swamplands is influenced by the types and the amounts of organic matter application

    Directory of Open Access Journals (Sweden)

    A R Saidy

    2015-05-01

    Full Text Available Farmers in tidal swamplands annually added organic matter (OM onto the raised beds to maintain organic matter contents and thereby maintain soil productivity of the raised beds. This experiment aimed to study the influence of the types and the amounts of OM on the stabilization of organic matter in the raised-bed soils. Four types of OM: rice straw, eceng gondok (Eichornia crassipes, purun tikus  (Eleocharis dulcis and mixed  rice straw-eceng gondok were added to a 27-year raised bed soil with 4 different rates: 0, 0.5, 1.0 and 2.0  of maximum sorption capacity (Qmax, and the OM stabilization was quantified after 10 weeks of OM addition.  Results of this study showed with the exception of rice straw, OM addition to soil resulted in increases in the mineralization of soil OM thereby inducing priming effect. Addition of rice straw at rate of 0.5 of Qmax resulted in stabilization of 46% added OM, while only 30% and 37% of added OM was stabilized when OM was added to soils at rates of 1.0 and 2.0 Qmax, respectively.  This study showed that the stabilization of OM in raised bed soils were influenced by the chemical composition of OM and the amount of added OM.

  19. Soil organic matter on citrus plantation in Eastern Spain

    Science.gov (United States)

    Cerdà, Artemi; Pereira, Paulo; Novara, Agata; Prosdocimi, Massimo

    2015-04-01

    Citrus plantations in Eastern Spain are the main crop and Valencia region is the largest world exporter. The traditional plantation are located on flood irrigated areas and the new plantation are located on slopes were drip irrigation is the source of the wetting. It has been demonstrate that the citrus plantations contribute to high erosion rates on slopes (Cerdà et al., 2009b) as it is usual on agriculture land (Cerdà et al., 2009a), but when organic farming is present the soil erosion is much lower (Cerdà and Jurgensen, 2008; Cerdà et al., 2009; Cerdà and Jurgensen, 2011). This is a worldwide phenomenon (Wu et al., 2007; Wu et al., 2011; Xu et al., 2010; Xu et al., 2012a; Xu et al., 2012b), which are a key factor of the high erosion rates in rural areas (García Orenes et al., 2009: García Orenes et al., 20010; García Orenes et al., 2012; Haregewyn et al., 2013; Zhao et al., 2013). The key factor of the contrasted response of soils to the rain in citrus is the organic matter cover. This is why the Soil Erosion and Degradation Research Team developed a survey to determine the soil erosion rates on citrus orchards under different managements. A hundred of samples were collected in a citrus plantation on slope under conventional management (Chemical management), one on organic farming, one on traditional flood irrigated organic farming and one on traditional chemical flooding farm. The organic farming soils were treated with 10000 Kg ha-1 of manure yearly. The results show that the mean soil organic matter content was 1.24 %, 3.54%, 5,43% and 2.1% respectively, which show a clear impact of organic farming in the recovery of the soil organic matter. meanwhile the on the slopes and the flood-irrigated soils are Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and PREVENTING AND REMEDIATING DEGRADATION OF SOILS IN EUROPE THROUGH LAND CARE (RECARE)FP7- ENV-2013- supported this research. References Cerdà, A., Flanagan, D.C., le Bissonnais

  20. Long-term citrus organic farming strategy results in soil organic matter recovery

    Science.gov (United States)

    Novara, Agata; Pereira, Paulo; Barone, Ettore; Giménez Morera, Antonio; Keesstra, Saskia; Gristina, Luciano; Jordán, Antonio; Parras-Alcantara, Luis; Cerdà, Artemi

    2017-04-01

    .: The significance of soils and soil science towards realization of the United Nations Sustainable Development Goals, SOIL, 2, 111-128, doi:10.5194/soil-2-111-2016, 2016. Keesstra, S.D., Geissen, V., van Schaik, L., Mosse., K., Piiranen, S., 2012. Soil as a filter for groundwater quality. Current Opinions in Environmental Sustainability 4, 507-516. doi:10.1016/j.cosust.2012.10.007 Laudicina, V. A., A. Novara, V. Barbera, M. Egli, and L. Badalucco. 2015. Long-Term Tillage and Cropping System Effects on Chemical and Biochemical Characteristics of Soil Organic Matter in a Mediterranean Semiarid Environment. Land Degradation and Development 26 (1): 45-53. doi:10.1002/ldr.2293. Mol, G., Keesstra, S.D., 2012. Editorial: Soil science in a changing world. Current Opinions in Environmental Sustainability 4: 473-477. Novara, A., L. Gristina, M. B. Bodì, and A. Cerdà. 2011. The Impact of Fire on Redistribution of Soil Organic Matter on a Mediterranean Hillslope Under Maquia Vegetation Type. Land Degradation and Development 22 (6): 530-536. doi:10.1002/ldr.1027. Parras-Alcántara, L., B. Lozano-García, E. C. Brevik, and A. Cerdá. 2015. Soil Organic Carbon Stocks Assessment in Mediterranean Natural Areas: A Comparison of Entire Soil Profiles and Soil Control Sections. Journal of Environmental Management 155: 219-228. doi:10.1016/j.jenvman.2015.03.039. Parras-Alcántara, L., B. Lozano-García, S. Keesstra, A. Cerdà, and E. C. Brevik. 2016. Long-Term Effects of Soil Management on Ecosystem Services and Soil Loss Estimation in Olive Grove Top Soils. Science of the Total Environment. doi:10.1016/j.scitotenv.2016.07.016.

  1. The method for determination of parameters of the phenomenological continual model of soil organic matter transformation

    Directory of Open Access Journals (Sweden)

    S. I. Bartsev

    2015-06-01

    Full Text Available A possible method for experimental determination of parameters of the previously proposed continual mathematical model of soil organic matter transformation is theoretically considered in this paper. The previously proposed by the authors continual model of soil organic matter transformation, based on using the rate of matter transformation as a continual scale of its recalcitrance, describes the transformation process phenomenologically without going into detail of microbiological mechanisms of transformation. Thereby simplicity of the model is achieved. The model is represented in form of one differential equation in first­order partial derivatives, which has an analytical solution in elementary functions. The model equation contains a small number of empirical parameters which generally characterize environmental conditions where the matter transformation process occurs and initial properties of the plant litter. Given the values of these parameters, it is possible to calculate dynamics of soil organic matter stocks and its distribution over transformation rate. In the present study, possible approaches for determination of the model parameters are considered and a simple method of their experimental measurement is proposed. An experiment of an incubation of chemically homogeneous samples in soil and multiple sequential measurement of the sample mass loss with time is proposed. An equation of time dynamics of mass loss of incubated homogeneous sample is derived from the basic assumption of the presented soil organic matter transformation model. Thus, fitting by the least squares method the parameters of sample mass loss curve calculated according the proposed mass loss dynamics equation allows to determine the parameters of the general equation of soil organic transformation model.

  2. Characteristics and Biodegradability of Wastewater Organic Matter in Municipal Wastewater Treatment Plants Collecting Domestic Wastewater and Industrial Discharge

    Directory of Open Access Journals (Sweden)

    Yun-Young Choi

    2017-06-01

    Full Text Available Municipal wastewater treatment plants (WWTPs in Korea collect and treat not only domestic wastewater, but also discharge from industrial complexes. However, some industrial discharges contain a large amount of non-biodegradable organic matter, which cannot be treated properly in a conventional biological WWTP. This study aimed to investigate the characteristics and biodegradability of the wastewater organic matter contained in the industrial discharges and to examine the fate of the industrial discharges in a biological WWTP. In contrast to most previous studies targeting a specific group of organic compounds or traditional water quality indices, such as biological oxygen demand (BOD and chemical oxygen demand (COD, this study was purposed to quantify and characterize the biodegradable and nonbiodegradable fractions of the wastewater organic matter. Chemical oxygen demand (COD fractionation tests and fluorescence spectroscopy revealed that the industrial discharge from dyeing or pulp mill factories contained more non-biodegradable soluble organic matter than did the domestic wastewater. Statistical analysis on the WWTPs’ monitoring data indicated that the industrial discharge containing non-biodegradable soluble organic matter was not treated effectively in a biological WWTP, but was escaping from the system. Thus, industrial discharge that contained non-biodegradable soluble organic matter was a major factor in the decrease in biodegradability of the discharge, affecting the ultimate fate of wastewater organic matter in a biological WWTP. Further application of COD fractionation and fluorescence spectroscopy to wastewaters, with various industrial discharges, will help scientists and engineers to better design and operate a biological WWTP, by understanding the fate of wastewater organic matter.

  3. Nitrogen isotopic composition of macromolecular organic matter in interplanetary dust particles

    Science.gov (United States)

    Aléon, Jérôme; Robert, François; Chaussidon, Marc; Marty, Bernard

    2003-10-01

    Nitrogen concentrations and isotopic compositions were measured by ion microprobe scanning imaging in two interplanetary dust particles L2021 K1 and L2036 E22, in which imaging of D/H and C/H ratios has previously evidenced the presence of D-rich macromolecular organic components. High nitrogen concentrations of 10-20 wt% and δ 15N values up to +400‰ are observed in these D-rich macromolecular components. The previous study of D/H and C/H ratios has revealed three different D-rich macromolecular phases. The one previously ascribed to macromolecular organic matter akin the insoluble organic matter (IOM) from carbonaceous chondrites is enriched in nitrogen by one order of magnitude compared to the carbonaceous chondrite IOM, although its isotopic composition is still similar to what is known from Renazzo (δ 15N = +208‰). The correlation observed in macromolecular organic material between the D- and 15N-excesses suggests that the latter originate probably from chemical reactions typical of the cold interstellar medium. These interstellar materials preserved to some extent in IDPs are therefore macromolecular organic components with various aliphaticity and aromaticity. They are heavily N-heterosubstituted as shown by their high nitrogen concentrations >10 wt%. They have high D/H ratios >10 -3 and δ 15N values ≥ +400‰. In L2021 K1 a mixture is observed at the micron scale between interstellar and chondritic-like organic phases. This indicates that some IDPs contain organic materials processed at various heliocentric distances in a turbulent nebula. Comparison with observation in comets suggests that these molecules may be cometary macromolecules. A correlation is observed between the D/H ratios and δ 15N values of macromolecular organic matter from IDPs, meteorites, the Earth and of major nebular reservoirs. This suggests that most macromolecular organic matter in the inner solar system was probably issued from interstellar precursors and further processed

  4. Rare earth elements and neodymium isotopes in sedimentary organic matter

    Science.gov (United States)

    Freslon, Nicolas; Bayon, Germain; Toucanne, Samuel; Bermell, Sylvain; Bollinger, Claire; Chéron, Sandrine; Etoubleau, Joel; Germain, Yoan; Khripounoff, Alexis; Ponzevera, Emmanuel; Rouget, Marie-Laure

    2014-09-01

    We report rare earth element (REE) and neodymium (Nd) isotope data for the organic fraction of sediments collected from various depositional environments, i.e. rivers (n = 25), estuaries (n = 18), open-ocean settings (n = 15), and cold seeps (n = 12). Sedimentary organic matter (SOM) was extracted using a mixed hydrogen peroxide/nitric acid solution (20%-H2O2-0.02 M-HNO3), after removal of carbonate and oxy-hydroxide phases with dilute hydrochloric acid (0.25 M-HCl). A series of experimental tests indicate that extraction of sedimentary organic compounds using H2O2 may be complicated occasionally by partial dissolution of sulphide minerals and residual carbonates. However, this contamination is expected to be minor for REE because measured concentrations in H2O2 leachates are about two-orders of magnitude higher than in the above mentioned phases. The mean REE concentrations determined in the H2O2 leachates for samples from rivers, estuaries, coastal seas and open-ocean settings yield relatively similar levels, with ΣREE = 109 ± 86 ppm (mean ± s; n = 58). The organic fractions leached from cold seep sediments display even higher concentration levels (285 ± 150 ppm; mean ± s; n = 12). The H2O2 leachates for most sediments exhibit remarkably similar shale-normalized REE patterns, all characterized by a mid-REE enrichment compared to the other REE. This suggests that the distribution of REE in leached sedimentary organic phases is controlled primarily by biogeochemical processes, rather than by the composition of the source from which they derive (e.g. pore, river or sea-water). The Nd isotopic compositions for organic phases leached from river sediments are very similar to those for the corresponding detrital fractions. In contrast, the SOM extracted from marine sediments display εNd values that typically range between the εNd signatures for terrestrial organic matter (inferred from the analysis of the sedimentary detrital fractions) and marine organic matter

  5. Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands.

    Science.gov (United States)

    Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro

    2013-10-15

    The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Distribution of transformed organic matter in structural units of loamy sandy soddy-podzolic soil

    Science.gov (United States)

    Kogut, B. M.; Yashin, M. A.; Semenov, V. M.; Avdeeva, T. N.; Markina, L. G.; Lukin, S. M.; Tarasov, S. I.

    2016-01-01

    The effect of land use types and fertilizing systems on the structural and aggregate composition of loamy sandy soddy-podzolic soil and the quantitative parameters of soil organic matter has been studied. The contribution of soil aggregates 2-1 mm in size to the total Corg reserve in the humus horizon is higher than the contributions of other aggregates by 1.3-4.2 times. Reliable correlations have been revealed between the contents of total (Corg), labile (Clab), and active (C0) organic matter in the soil. The proportion of C0 is 44-70% of Clab extractable by neutral sodium pyrophosphate solution. The contributions of each of the 2-1, 0.5-0.25, and fractions to the total C0 reserve are 14-21%; the contributions of each of the other fractions are 4-12%. The chemically labile and biologically active components of humic substances reflect the quality changes of soil organic matter under agrogenic impacts. A conceptual scheme has been proposed for the subdivision of soil organic matter into the active, slow (intermediate), and passive pools. In the humus horizon of loamy sandy soddy-podzolic soil, the active, slow, and passive pools contain 6-11, 34-65, and 26-94% of the total Corg, respectively.

  7. Investigation of vertical distribution and morphology of indigenous organic matter at Sleeping Bear site, Michigan

    Science.gov (United States)

    West, C. C.; Lyon, W. G.; Ross, D. L.; Pennington, L. K.

    1994-11-01

    This study evaluates the nature and origin of particulate organic carbon and organic coatings on aquifer sands upgradient from a fuel spill site near the Sleeping Bear Dunes National Lakeshore in Michigan. The distribution of carbon was found to be highly complex due to the occurrence of high organic carbon horizons, bounded above and below by high carbonate sediments. The organic coatings on the sands were examined using white light and fluorescence microscopy and by scanning electron microscopy. Core samples were analyzed for organic and inorganic carbon, solution pH, humic/fulvic acid ratios, and insoluble organic matter content (that is, humin) as a function of depth from the ground surface. The organic geochemistry of the soil profile at this site was found to be significantly influenced by the carbonates producing a sharp boundary of precipitated organic matter. This boundary was followed by coatings of predominantly fulvic acid salts on mineral grains deeper in the soil column. The coatings extended into the aquifer. The existence of native organic films on sand grains is well documented in the soils literature. The study reported here was greatly aided by this information and provides the framework for future studies concerning the influence of carbon distribution, chemical identity, and morphology on contaminant fate and transport processes.

  8. Using soil organic matter fractions as indicators of soil physical quality

    DEFF Research Database (Denmark)

    Pulido Moncada, Mansonia A.; Lozano, Z; Delgado, M

    2018-01-01

    The objective of this study was to evaluate the use of chemical and physical fractions of soil organic matter (SOM), rather than SOM per se, as indicators of soil physical quality (SPQ) based on their effect on aggregate stability (AS). Chemically extracted humic and fulvic acids (HA and FA) were...... used as chemical fractions, and heavy and light fractions (HF and LF) obtained by density separation as physical fractions. The analyses were conducted on medium-textured soils from tropical and temperate regions under cropland and pasture. Results show that soil organic carbon (SOC), SOM fractions...... and AS appear to be affected by land use regardless of the origin of the soils. A general separation of structurally stable and unstable soils between samples of large and small SOC content, respectively, was observed. SOM fractions did not show a better relationship with AS than SOC per se. In both...

  9. Global chemical composition of ambient fine particulate matter for exposure assessment.

    Science.gov (United States)

    Philip, Sajeev; Martin, Randall V; van Donkelaar, Aaron; Lo, Jason Wai-Ho; Wang, Yuxuan; Chen, Dan; Zhang, Lin; Kasibhatla, Prasad S; Wang, Siwen; Zhang, Qiang; Lu, Zifeng; Streets, David G; Bittman, Shabtai; Macdonald, Douglas J

    2014-11-18

    Epidemiologic and health impact studies are inhibited by the paucity of global, long-term measurements of the chemical composition of fine particulate matter. We inferred PM2.5 chemical composition at 0.1° × 0.1° spatial resolution for 2004-2008 by combining aerosol optical depth retrieved from the MODIS and MISR satellite instruments, with coincident profile and composition information from the GEOS-Chem global chemical transport model. Evaluation of the satellite-model PM2.5 composition data set with North American in situ measurements indicated significant spatial agreement for secondary inorganic aerosol, particulate organic mass, black carbon, mineral dust, and sea salt. We found that global population-weighted PM2.5 concentrations were dominated by particulate organic mass (11.9 ± 7.3 μg/m(3)), secondary inorganic aerosol (11.1 ± 5.0 μg/m(3)), and mineral dust (11.1 ± 7.9 μg/m(3)). Secondary inorganic PM2.5 concentrations exceeded 30 μg/m(3) over East China. Sensitivity simulations suggested that population-weighted ambient PM2.5 from biofuel burning (11 μg/m(3)) could be almost as large as from fossil fuel combustion sources (17 μg/m(3)). These estimates offer information about global population exposure to the chemical components and sources of PM2.5.

  10. Chloroacetic acids - Degradation intermediates of organic matter in forest soil

    Czech Academy of Sciences Publication Activity Database

    Matucha, Miroslav; Gryndler, Milan; Schröder, P.; Forczek, Sándor; Uhlířová, H.; Fuksová, Květoslava; Rohlenová, Jana

    2007-01-01

    Roč. 39, č. 1 (2007), s. 382-385 ISSN 0038-0717 R&D Projects: GA ČR GA522/02/0874; GA ČR GA526/05/0636 Institutional research plan: CEZ:AV0Z50380511 Keywords : trichloroacetic acid * dichloroacetic acid * chlorination * soil organic matter Subject RIV: EF - Botanics Impact factor: 2.580, year: 2007

  11. Peatland Organic Matter Chemistry Trends Over a Global Latitudinal Gradient

    Science.gov (United States)

    Verbeke, B. A.; Hodgkins, S. B.; Carson, M. A.; Lamit, L. J.; Lilleskov, E.; Chanton, J.

    2017-12-01

    Peatlands contain a significant amount of the global soil carbon, and the climate feedback of carbon cycling within these peatland systems is still relatively unknown. Organic matter composition of peatlands plays a major role in determining carbon storage, and while high latitude peatlands seem to be the most sensitive to climate change, a global picture of peat organic matter chemistry is required to improve predictions and models of greenhouse gas emissions fueled by peatland decomposition. The objective of this research is to test the hypothesis that carbohydrate content of peatlands near the equator will be lower than high latitude peatlands, while aromatic content will be higher. As a part of the Global Peatland Microbiome Project (GPMP), around 2000 samples of peat from 10 to 70 cm across a latitudinal gradient of 79 N to 53 S were measured with Fourier transform infrared spectroscopy (FTIR) to examine the organic matter functional groups of peat. Carbohydrate and aromatic content, as determined by FTIR, are useful proxies of decomposition potential and recalcitrance, respectively. We found a highly significant relationship between carbohydrate and aromatic content, latitude, and depth. Carbohydrate content of high latitude sites were significantly greater than at sites near the equator, in contrast to aromatic content which showed the opposite trend. It is also clear that carbohydrate content decreases with depth while aromatic content increases with depth. Higher carbohydrate content at higher latitudes indicates a greater potential for lability and resultant mineralization to form the greenhouse gases, carbon dioxide and methane, whereas the composition of low latitude peatlands is consistent with their apparent stability. We speculate that the combination of low carbohydrates and high aromatics at warmer locations near the equator could foreshadow the organic matter composition of high latitude peat transitioning to a more recalcitrant form with a

  12. Proceedings of the Regional Colloquium on Soil Organic Matter Studies

    International Nuclear Information System (INIS)

    Cerri, C.C.; Athie, D.; Sodrzeieski, D.

    1982-01-01

    Isotope techniques are applied to soil organic matter studies, with special emphasis to decomposition studies. The effect of N fertilizers on the development of wheat and soybean crops is studied, as well as N-fixation. 14 C and 15 N are used as tracers; 13 C/ 12 C ratios are determined in humic horizons of soils. The influence of carbon sources addition on the degradation of the pesticide carbaril in soils is evaluated. (M.A.) [pt

  13. Production of Dissolved Organic Matter During Doliolid Feeding

    Science.gov (United States)

    Castellane, N. J.; Paffenhofer, G. A.; Stubbins, A.

    2016-02-01

    The biological carbon pump (BCP) draws carbon dioxide out of the atmosphere and buries it at the seafloor. The efficiency of the BCP is determined in part by the sinking rates of particulate organic carbon (POC) from ocean surface waters. Zooplankton can package POC into fecal pellets with higher sinking rates than their food source (e.g. phytoplankton), increasing the efficiency of the BCP. However, dissolved organic carbon (DOC) is also produced as zooplankton ingest and egest food, reducing the efficiency of BCP. The pelagic tunicate Dolioletta gegenbauri (doliolid) is a gelatinous zooplankton found at high concentrations in shelf waters, including our study site: the South Atlantic Bight. Doliolids are efficient grazers capable of stripping large quantities of phytoplankton from the water column. To determine the balance between pellet formation and DOC production during feeding, doliolids (6-7 mm gonozooids) were placed in natural seawater amended with a live phytoplankton food source and incubated on a plankton wheel. Dissolved organic matter (DOM) released directly to the water as well as the water soluble fraction of pellet organic matter were quantified and optically characterized. Colored dissolved organic matter (CDOM) absorbance and fluorescence spectra revealed that doliolid feeding produces DOM with optical properties that are commonly indicative of newly produced, highly biolabile DOM of microbial origin. Based upon these optical characteristics, doliolid-produced DOM is expected to be highly bio-labile in the environment and therefore rapidly degraded by surface ocean microbes shunting phytoplankton-derived organic carbon out of the BCP and back to dissolved inorganic carbon.

  14. Sea cucumbers reduce chromophoric dissolved organic matter in aquaculture tanks.

    Science.gov (United States)

    Sadeghi-Nassaj, Seyed Mohammad; Catalá, Teresa S; Álvarez, Pedro A; Reche, Isabel

    2018-01-01

    Mono-specific aquaculture effluents contain high concentrations of nutrients and organic matter, which affect negatively the water quality of the recipient ecosystems. A fundamental feature of water quality is its transparency. The fraction of dissolved organic matter that absorbs light is named chromophoric dissolved organic matter (CDOM). A sustainable alternative to mono-specific aquaculture is the multitrophic aquaculture that includes species trophically complementary named "extractive" species that uptake the waste byproducts. Sea cucumbers are recognized as efficient extractive species due to the consumption of particulate organic matter (POM). However, the effects of sea cucumbers on CDOM are still unknown. During more than one year, we monitored CDOM in two big-volume tanks with different trophic structure. One of the tanks (-holothurian) only contained around 810 individuals of Anemonia sulcata , whereas the other tank (+holothurian) also included 90 individuals of Holothuria tubulosa and Holothuria forskali . We routinely analyzed CDOM absorption spectra and determined quantitative (absorption coefficients at 325 nm) and qualitative (spectral slopes) optical parameters in the inlet waters, within the tanks, and in their corresponding effluents. To confirm the time-series results, we also performed three experiments. Each experiment consisted of two treatments: +holothurians (+H) and -holothurians (-H). We set up three +H tanks with 80 individuals of A. sulcata and 10 individuals of H. tubulosa in each tank and four -H tanks that contained only 80 individuals of A. sulcata . In the time-series, absorption coefficients at 325 nm ( a 325 ) and spectral slopes from 275 to 295 nm ( S 275-295 ) were significantly lower in the effluent of the +holothurian tank (average: 0.33 m -1 and 16 µm -1 , respectively) than in the effluent of the -holothurian tank (average: 0.69 m -1 and 34 µm -1 , respectively), the former being similar to those found in the inlet

  15. Integrated evaluation of soil quality after the incorporation of organic matter and microorganisms

    Directory of Open Access Journals (Sweden)

    Valarini Pedro J.

    2002-01-01

    Full Text Available The soil quality was evaluated following the addition of organic matter and microorganisms to a clay loam soil collected in Aranjuez (Madrid under controlled conditions of temperature and moisture, and over a period of three months. The following treatments were carried out: soil (control; soil + 50 t/ha of animal manure (E50; soil + 50 t/ha of animal manure + 30l/ha of effective microorganisms (E50EM; soil + 30 t/ha of combination of various green crop residues and weeds (RC30 and soil + 30 t/ha of combination of various green crop residues and weeds + 30l/ha of effective microorganisms (RC30EM. The soil samples were taken before and after the incubation and analysed using physical, chemical and microbiological parameters. A significant increase in the production of polysaccharides and alkaline phosphatase and esterase enzymes in the treatments E50EM and RC30EM was observed, being in direct correlation with the humification of the organic matter, with the water retention at field capacity, and with the cationic exchange capacity (CEC. It can be concluded that the incorporation of microorganisms EM potentialized the soil biological activity and improved physico-chemical soil properties, contributing to a quick humification of fresh organic matter. Those findings were proved by microbiological activities of exopolysaccharides by alcaline phosphatase and esterase enzymes, which can be used as earlier and integral soil health indicators.

  16. Iron oxides and quality of organic matter in sugarcane harvesting systems

    Directory of Open Access Journals (Sweden)

    Diogo Mazza Barbieri

    2014-08-01

    Full Text Available Improvements in working conditions, sustainable production, and competitiveness have led to substantial changes in sugarcane harvesting systems. Such changes have altered a number of soil properties, including iron oxides and organic matter, as well as some chemical properties, such as the maximum P adsorption capacity of the soil. The aim of this study was to characterize the relationship between iron oxides and the quality of organic matter in sugarcane harvesting systems. For that purpose, two 1 ha plots in mechanically and manually harvested fields were used to obtain soil samples from the 0.00-0.25 m soil layer at 126 different points. The mineralogical, chemical, and physical results were subjected to descriptive statistical analyses, such as the mean comparison test, as well as to multivariate statistical and principal component analyses. Multivariate tests allowed soil properties to be classified in two different groups according to the harvesting method: manual harvest with the burning of residual cane, and mechanical harvest without burning. The mechanical harvesting system was found to enhance pedoenvironmental conditions, leading to changes in the crystallinity of iron oxides, an increase in the humification of organic matter, and a relative decrease in phosphorus adsorption in this area compared to the manual harvesting system.

  17. Assessment of soil properties by organic matter and EM-microorganism incorporation

    Directory of Open Access Journals (Sweden)

    Valarini P. J.

    2003-01-01

    Full Text Available Properties of a claim loam soil, collected in Aranjuez (Madrid and enriched with organic matter and microorganisms, were evaluated under controlled temperature and moisture conditions, over a period of three months. The following treatments were carried out: soil (control; soil + 50 t ha-1 of animal manure (E50; soil + 50 t ha-1 of animal manure + 30 L ha-1 of effective microorganisms (E50EM; soil + 30 t ha-1 of the combination of various green crop residues and weeds (RC30 and soil + 30 t ha-1 of the combination of various green crop residues and weeds + 30 L ha-1 of effective microorganisms (RC30EM. Soil samples were taken before and after incubation and their physical, chemical, and microbiological parameters analyzed. Significant increase was observed in the production of exopolysaccharides and basic phosphatase and esterase enzyme activities in the treatments E50EM and RC30EM, in correlation with the humification of organic matter, water retention at field capacity, and the cationic exchange capacity (CEC of the same treatments. The conclusion was drawn that the incorporation of a mixture of effective microorganisms (EM intensified the biological soil activity and improved physical and chemical soil properties, contributing to a quick humification of fresh organic matter. These findings were illustrated by the microbiological activities of exopolysaccharides and by alkaline phosphatase and esterase enzymes, which can be used as early and integrated soil health indicators.

  18. A GCM study of organic matter in marine aerosol and its potential contribution to cloud drop activation

    Directory of Open Access Journals (Sweden)

    G. J. Roelofs

    2008-02-01

    Full Text Available With the global aerosol-climate model ECHAM5-HAM we investigate the potential influence of organic aerosol originating from the ocean on aerosol mass and chemical composition and the droplet concentration and size of marine clouds. We present sensitivity simulations in which the uptake of organic matter in the marine aerosol is prescribed for each aerosol mode with varying organic mass and mixing state, and with a geographical distribution and seasonality similar to the oceanic emission of dimethyl sulfide. Measurements of aerosol mass, aerosol chemical composition and cloud drop effective radius are used to assess the representativity of the model initializations. Good agreement with the measurements is obtained when organic matter is added to the Aitken, accumulation and coarse modes simultaneously. Representing marine organics in the model leads to higher cloud drop number concentrations and thus smaller cloud drop effective radii, and this improves the agreement with measurements. The mixing state of the organics and the other aerosol matter, i.e. internal or external depending on the formation process of aerosol organics, is an important factor for this. We estimate that globally about 75 Tg C yr−1 of organic matter from marine origin enters the aerosol phase, with comparable contributions from primary emissions and secondary organic aerosol formation.

  19. Influence of chlorothalonil on the removal of organic matter in horizontal subsurface flow constructed wetlands.

    Science.gov (United States)

    Casas-Zapata, Juan C; Ríos, Karina; Florville-Alejandre, Tomás R; Morató, Jordi; Peñuela, Gustavo

    2013-01-01

    This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.

  20. Soil Quality of Restinga Forest: Organic Matter and Aluminum Saturation

    Science.gov (United States)

    Rodrigues Almeida Filho, Jasse; Casagrande, José Carlos; Martins Bonilha, Rodolfo; Soares, Marcio Roberto; Silva, Luiz Gabriel; Colato, Alexandre

    2013-04-01

    The restinga vegetation (sand coastal plain vegetation) consists of a mosaic of plant communities, which are defined by the characteristics of the substrates, resulting from the type and age of the depositional processes. This mosaic complex of vegetation types comprises restinga forest in advanced (high restinga) and medium regeneration stages (low restinga), each with particular differentiating vegetation characteristics. Of all ecosystems of the Atlantic Forest, restinga is the most fragile and susceptible to anthropic disturbances. The purpose of this study was evaluating the organic matter and aluminum saturation effects on soil quality index (SQI). Two locations were studied: State Park of the Serra do Mar, Picinguaba, in the city of Ubatuba (23°20' e 23°22' S / 44°48' e 44°52' W), and State Park of Cardoso Island in the city of Cananéia (25°03'05" e 25°18'18" S / 47°53'48" e 48° 05'42" W). The soil samples were collect at a depth of 0-10 cm, where concentrate 70% of vegetation root system. Was studied an additive model to evaluate soil quality index. The shallow root system development occurs due to low calcium levels, whose disability limits their development, but also can reflect on delay, restriction or even in the failure of the development vegetation. The organic matter is kept in the soil restinga ecosystem by high acidity, which reduces the decomposition of soil organic matter, which is very poor in nutrients. The base saturation, less than 10, was low due to low amounts of Na, K, Ca and Mg, indicating low nutritional reserve into the soil, due to very high rainfall and sandy texture, resulting in high saturation values for aluminum. Considering the critical threshold to 3% organic matter and for aluminum saturation to 40%, the IQS ranged from 0.95 to 0.1 as increased aluminum saturation and decreased the soil organic matter, indicating the main limitation to the growth of plants in this type of soil, when deforested.

  1. Terrestrial dissolved organic matter distribution in the North Sea.

    Science.gov (United States)

    Painter, Stuart C; Lapworth, Dan J; Woodward, E Malcolm S; Kroeger, Silke; Evans, Chris D; Mayor, Daniel J; Sanders, Richard J

    2018-07-15

    The flow of terrestrial carbon to rivers and inland waters is a major term in the global carbon cycle. The organic fraction of this flux may be buried, remineralized or ultimately stored in the deep ocean. The latter can only occur if terrestrial organic carbon can pass through the coastal and estuarine filter, a process of unknown efficiency. Here, data are presented on the spatial distribution of terrestrial fluorescent and chromophoric dissolved organic matter (FDOM and CDOM, respectively) throughout the North Sea, which receives organic matter from multiple distinct sources. We use FDOM and CDOM as proxies for terrestrial dissolved organic matter (tDOM) to test the hypothesis that tDOM is quantitatively transferred through the North Sea to the open North Atlantic Ocean. Excitation emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) revealed a single terrestrial humic-like class of compounds whose distribution was restricted to the coastal margins and, via an inverse salinity relationship, to major riverine inputs. Two distinct sources of fluorescent humic-like material were observed associated with the combined outflows of the Rhine, Weser and Elbe rivers in the south-eastern North Sea and the Baltic Sea outflow to the eastern central North Sea. The flux of tDOM from the North Sea to the Atlantic Ocean appears insignificant, although tDOM export may occur through Norwegian coastal waters unsampled in our study. Our analysis suggests that the bulk of tDOM exported from the Northwest European and Scandinavian landmasses is buried or remineralized internally, with potential losses to the atmosphere. This interpretation implies that the residence time in estuarine and coastal systems exerts an important control over the fate of tDOM and needs to be considered when evaluating the role of terrestrial carbon losses in the global carbon cycle. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  2. Soil organic matter regulates molybdenum storage and mobility in forests

    Science.gov (United States)

    Marks, Jade A; Perakis, Steven; King, Elizabeth K.; Pett-Ridge, Julie

    2015-01-01

    The trace element molybdenum (Mo) is essential to a suite of nitrogen (N) cycling processes in ecosystems, but there is limited information on its distribution within soils and relationship to plant and bedrock pools. We examined soil, bedrock, and plant Mo variation across 24 forests spanning wide soil pH gradients on both basaltic and sedimentary lithologies in the Oregon Coast Range. We found that the oxidizable organic fraction of surface mineral soil accounted for an average of 33 %of bulk soil Mo across all sites, followed by 1.4 % associated with reducible Fe, Al, and Mn-oxides, and 1.4 % in exchangeable ion form. Exchangeable Mo was greatest at low pH, and its positive correlation with soil carbon (C) suggests organic matter as the source of readily exchangeable Mo. Molybdenum accumulation integrated over soil profiles to 1 m depth (τMoNb) increased with soil C, indicating that soil organic matter regulates long-term Mo retention and loss from soil. Foliar Mo concentrations displayed no relationship with bulk soil Mo, and were not correlated with organic horizon Mo or soil extractable Mo, suggesting active plant regulation of Mo uptake and/or poor fidelity of extractable pools to bioavailability. We estimate from precipitation sampling that atmospheric deposition supplies, on average, over 10 times more Mo annually than does litterfall to soil. In contrast, bedrock lithology had negligible effects on foliar and soil Mo concentrations and on Mo distribution among soil fractions. We conclude that atmospheric inputs may be a significant source of Mo to forest ecosystems, and that strong Mo retention by soil organic matter limits ecosystem Mo loss via dissolution and leaching pathways.

  3. Leaching of organic acids from macromolecular organic matter by non-supercritical CO2

    Science.gov (United States)

    Sauer, P.; Glombitza, C.; Kallmeyer, J.

    2012-04-01

    The storage of CO2 in underground reservoirs is discussed controversly in the scientific literature. The worldwide search for suitable storage formations also considers coal-bearing strata. CO2 is already injected into seams for enhanced recovery of coal bed methane. However, the effects of increased CO2 concentration, especially on organic matter rich formations, are rarely investigated. The injected CO2 will dissolve in the pore water, causing a decrease in pH and resulting in acidic formation waters. Huge amounts of low molecular weight organic acids (LMWOAs) are chemically bound to the macromolecular matrix of sedimentary organic matter and may be liberated by hydrolysis, which is enhanced by the acidic porewater. Recent investigations outlined the importance of LMWOAs as a feedstock for microbial life in the subsurface [1]. Therefore, injection of CO2 into coal formations may result in enhanced nutrient supply for subsurface microbes. To investigate the effect of high concentrations of dissolved CO2 on the release of LMWOAs from coal we developed an inexpensive high-pressure high temperature system that allows manipulating the partial pressure of dissolved gases at pressures and temperatures up to 60 MPa and 120° C, respectively. In a reservoir vessel, gases are added to saturate the extraction medium to the desired level. Inside the extraction vessel hangs a flexible and inert PVDF sleeve (polyvinylidene fluoride, almost impermeable for gases), holding the sample and separating it from the pressure fluid. The flexibility of the sleeve allows for subsampling without loss of pressure. Coal samples from the DEBITS-1 well, Waikato Basin, NZ (R0 = 0.29, TOC = 30%). were extracted at 90° C and 5 MPa, either with pure or CO2-saturated water. Subsamples were taken at different time points during the extraction. The extracted LMWOAs such as formate, acetate and oxalate were analysed by ion chromatography. Yields of LMWOAs were higher with pure water than with CO2

  4. Test procedure for determining organic matter content in soils : UV-VIS method.

    Science.gov (United States)

    2010-11-01

    The Texas Department of Transportation has been having problems with organic matter in soils that they : stabilize for use as subgrade layers in road construction. The organic matter reduces the effectiveness of : common soil additives (lime/cement) ...

  5. SOIL NITROGEN TRANSFORMATIONS AND ROLE OF LIGHT FRACTION ORGANIC MATTER IN FOREST SOILS

    Science.gov (United States)

    Depletion of soil organic matter through cultivation may alter substrate availability for microbes, altering the dynamic balance between nitrogen (N) immobilization and mineralization. Soil light fraction (LF) organic matter is an active pool that decreases upon cultivation, and...

  6. Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter.

    Science.gov (United States)

    Liu, Chia-Chuan; Kar, Sandeep; Jean, Jiin-Shuh; Wang, Chung-Ho; Lee, Yao-Chang; Sracek, Ondra; Li, Zhaohui; Bundschuh, Jochen; Yang, Huai-Jen; Chen, Chien-Yen

    2013-11-15

    The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ(18)O-rich fluids may be associated with silicate and carbonate mineral released through water-rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of organic matter among the mud volcanoes being examined. Because arsenate concentration in the mud fluids was found to be independent from geochemical factors, it was considered that organic matter may induce arsenic mobilization through an adsorption/desorption mechanism with humic substances under reducing conditions. Organic matter therefore plays a significant role in the mobility of arsenic in mud volcanoes. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Optimizing Hollow Fibre Nanofiltration for Organic Matter Rich Lake Water

    Directory of Open Access Journals (Sweden)

    Alexander Keucken

    2016-09-01

    Full Text Available Over the years, various technologies have been utilized for Natural Organic Matter (NOM removal with varying degrees of success. Conventional treatment methods comprising of coagulation, flocculation, sedimentation, or filtration are widely used to remove NOM. An alternative to these conventional methods is to use spiral wound membranes. These membranes tend to remove too much hardness whilst being ineffective in disinfection. They also have a low tolerance to chlorine and thus, have limited chemical cleaning options. In this study, we investigated how an alternative and new innovative filtration concept, based on capillary NF membranes from modified polyethersulfone (PES, may be used to treat soft but humus-rich surface waters. Comprehensive performance tests, with a fully automated membrane pilot equipped with a full-scale sized test module (40 m2 membrane surface, were conducted at WTP Görvälnverket, which is operated by the water utility Norrvatten, providing drinking water from Mälaren (SUVA = 2.7–3.3, TOC = 7.0–10.0 mg·L−1 for about 500,000 people in the northern part of the Swedish capital of Stockholm. The removal of both UV and DOC was modeled using a solution diffusion approach. The optimized parameters allow deducing optimal operation conditions with respect to energy, water consumption, and permeate water quality. Optimal cross flow velocity was determined to be 0.75 m·s−1 at 80% recovery and a flux of 12–18 L·m−2·h−1. Under these conditions, 80% of the UV, 75% of the Humic Substances (MW = 600 and 70% of TOC were removed (from 8 to below 2 mg·L−1. A higher cross flow velocity led to marginal improvement (+2% while both higher and lower membrane fluxes degraded permeate water quality. Apparent optimized diffusion coefficients for UV and TOC were around 1.2–2.4 × 10−10·m2·s−1 and were similar to values found in the literature. Due to their higher diffusion coefficients and higher permeability

  8. Peat decomposability in managed organic soils in relation to land use, organic matter composition and temperature

    Directory of Open Access Journals (Sweden)

    C. Bader

    2018-02-01

    Full Text Available Organic soils comprise a large yet fragile carbon (C store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM, typically increasing in the order forest < grassland < cropland. However, there is also large variation in decomposition due to differences in hydrological conditions, climate and specific management. Here we studied the role of SOM composition on peat decomposability in a variety of differently managed drained organic soils. We collected a total of 560 samples from 21 organic cropland, grassland and forest soils in Switzerland, monitored their CO2 emission rates in lab incubation experiments over 6 months at two temperatures (10 and 20 °C and related them to various soil characteristics, including bulk density, pH, soil organic carbon (SOC content and elemental ratios (C / N, H / C and O / C. CO2 release ranged from 6 to 195 mg CO2-C g−1 SOC at 10 °C and from 12 to 423 mg g−1 at 20 °C. This variation occurring under controlled conditions suggests that besides soil water regime, weather and management, SOM composition may be an underestimated factor that determines CO2 fluxes measured in field experiments. However, correlations between the investigated chemical SOM characteristics and CO2 emissions were weak. The latter also did not show a dependence on land-use type, although peat under forest was decomposed the least. High CO2 emissions in some topsoils were probably related to the accrual of labile crop residues. A comparison with published CO2 rates from incubated mineral soils indicated no difference in SOM decomposability between these soil classes, suggesting that accumulation of recent, labile plant materials that presumably account for most of the evolved CO2 is not systematically different between mineral and organic soils. In our data set, temperature sensitivity of decomposition (Q10 on average 2.57

  9. Role of organic matter in uranium mineralisation in Vempalle dolostone; Cuddapah basin, India

    International Nuclear Information System (INIS)

    Goswami, Sukanta; Bhagat, Sangeeta; Zakaulla, Syed; Kumar, Suresh; Rai, A.K.

    2017-01-01

    Dolostone of Vempalle Formation near Tummalapalle hosts large uranium deposit (>100,000 tonnes with an average grade of 0.045% U_3O_8). It is a unique type of uranium deposit because carbonate formations have been considered to be among the least uraniferous of all the rocks of the Earth's crust due to mobility of uranium in aqueous fluid in the presence of carbonate and bicarbonate ions. Vempalle dolostone hosts syn-sedimentary uranium mineralization in the form of discrete uranium phases (pitchblende and coffinite) associated with collophane, and adsorbed uranium in organic matter. The organic matter has played dual role of concentrating uranium from solution and also chemically reducing it to pitchhblende and coffinite. (author)

  10. Effects of Organic Matter and Clay Content in Soil on Pesticide Adsorption Processes

    Directory of Open Access Journals (Sweden)

    Rada Đurović

    2009-01-01

    Full Text Available The effect of organic matter and clay content on the adsorption of atrazine, acetochlor, clomazone, pendimethalin and oxyfluorfen in soil samples was studied. In order to determine whether and to what degree different soil properties affect the process of determinationof selected pesticides, three soils with different clay and organic matter contents were used. An optimized liquid-solid extraction procedure followed by SPME measurement was applied to analyse the selected pesticides in soil samples. Detection and quantificationwere done by gas chromatography-mass spectrometry (GC/MS. Relative standard deviation (RSD values for multiple analyses of soil samples fortified at 30 μg/kg of each pesticide were below 19%. Limits of detection (LODs for all compounds studied were less than 2 μg/kg. The results indicate that soils with different physico-chemical properties have different effects on the adsorption of most pesticides, especially at higher concentration levels.

  11. Organic matter and soil structure in the Everglades Agricultural Area

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Alan L. [Univ. of Florida, Gainesville, FL (United States); Hanlon, Edward A. [Univ. of Florida, Gainesville, FL (United States)

    2013-01-01

    This publication pertains to management of organic soils (Histosols) in the Everglades Agricultural Area (EAA). These former wetland soils are a major resource for efficient agricultural production and are important globally for their high organic matter content. Recognition of global warming has led to considerable interest in soils as a repository for carbon. Soils rich in organic matter essentially sequester or retain carbon in the profile and can contribute directly to keeping that sequestered carbon from entering the atmosphere. Identification and utilization of management practices that minimize the loss of carbon from organic soils to the atmosphere can minimize effects on global warming and increase the longevity of subsiding Histosols for agricultural use. Understanding and predicting how these muck soils will respond to current and changing land uses will help to manage soil carbon. The objectives of this document are to: a. Discuss organic soil oxidation relative to storing or releasing carbon and nitrogen b. Evaluate effects of cultivation (compare structure for sugarcane vs. uncultivated soil) Based upon the findings from the land-use comparison (sugarcane or uncultivated), organic carbon was higher with cultivation in the lower depths. There is considerable potential for minimum tillage and residue management to further enhance carbon sequestration in the sugarcane system. Carbon sequestration is improved and soil subsidence is slowed with sugarcane production, and both of these are positive outcomes. Taking action to increase or maintain carbon sequestration appears to be appropriate but may introduce some risk to farming operations. Additional management methods are needed to reduce this risk. For both the longevity of these organic soils and from a global perspective, slowing subsidence through BMP implementation makes sense. Since these BMPs also have considerable societal benefit, it remains to be seen if society will help to offset a part or all

  12. Fluorescent dissolved organic matter in the continental shelf waters ...

    Indian Academy of Sciences (India)

    Ocean and receives a large freshwater influx ca. 1600 km3 yr ... oceanic surface area of 1.13%, this influx consti- ... the Bay. The export flux of total organic carbon ..... Cycles 20. GB2006. Benner R 2002 Chemical composition and reactivity;.

  13. Experimental Evidence for Abiotic Sulfurization of Marine Dissolved Organic Matter

    Directory of Open Access Journals (Sweden)

    Anika M. Pohlabeln

    2017-11-01

    Full Text Available Dissolved organic sulfur (DOS is the largest pool of organic sulfur in the oceans, and as such it is an important component of the global sulfur cycle. DOS in the ocean is resistant against microbial degradation and turns over on a millennium time scale. However, sources and mechanisms behind its stability are largely unknown. Here, we hypothesize that in sulfate-reducing sediments sulfur is abiotically incorporated into dissolved organic matter (DOM and released to the ocean. We exposed natural seawater and the filtrate of a plankton culture to sulfidic conditions. Already after 1-h at 20°C, DOS concentrations had increased 4-fold in these experiments, and 14-fold after 4 weeks at 50°C, indicating that organic matter does not need long residence times in natural sulfidic environments to be affected by sulfurization. Molecular analysis via ultrahigh-resolution mass spectrometry showed that sulfur was covalently and unselectively bound to DOM. Experimentally produced and natural DOS from sediments were highly similar on a molecular and structural level. By combining our data with published benthic DOC fluxes we estimate that 30–200 Tg DOS are annually transported from anaerobic and sulfate reducing sediments to the oceans. Uncertainties in this first speculative assessment are large. However, this first attempt illustrates that benthic DOS flux is potentially one order of magnitude larger than that via rivers indicating that this could balance the estimated global net removal of refractory DOS.

  14. White matter microstructural organization and gait stability in older adults

    Directory of Open Access Journals (Sweden)

    Sjoerd M. Bruijn

    2014-06-01

    Full Text Available Understanding age-related decline in gait stability and the role of alterations in brain structure is crucial. Here, we studied the relationship between white matter microstructural organization using Diffusion Tensor Imaging (DTI and advanced gait stability measures in 15 healthy young adults (range 18-30 years and 25 healthy older adults (range 62-82 years.Among the different gait stability measures, only stride time and the maximum Lyapunov exponent (which quantifies how well participants are able to attenuate small perturbations were found to decline with age. White matter microstructural organization (FA was lower throughout the brain in older adults. We found a strong correlation between FA in the left anterior thalamic radiation and left corticospinal tract on the one hand, and step width and safety margin (indicative of how close participants are to falling over on the other. These findings suggest that white matter FA in tracts connecting subcortical and prefrontal areas is associated with the implementation of an effective stabilization strategy during gait.

  15. The global distribution and dynamics of chromophoric dissolved organic matter.

    Science.gov (United States)

    Nelson, Norman B; Siegel, David A

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) is a ubiquitous component of the open ocean dissolved matter pool, and is important owing to its influence on the optical properties of the water column, its role in photochemistry and photobiology, and its utility as a tracer of deep ocean biogeochemical processes and circulation. In this review, we discuss the global distribution and dynamics of CDOM in the ocean, concentrating on developments in the past 10 years and restricting our discussion to open ocean and deep ocean (below the main thermocline) environments. CDOM has been demonstrated to exert primary control on ocean color by its absorption of light energy, which matches or exceeds that of phytoplankton pigments in most cases. This has important implications for assessing the ocean biosphere via ocean color-based remote sensing and the evaluation of ocean photochemical and photobiological processes. The general distribution of CDOM in the global ocean is controlled by a balance between production (primarily microbial remineralization of organic matter) and photolysis, with vertical ventilation circulation playing an important role in transporting CDOM to and from intermediate water masses. Significant decadal-scale fluctuations in the abundance of global surface ocean CDOM have been observed using remote sensing, indicating a potentially important role for CDOM in ocean-climate connections through its impact on photochemistry and photobiology.

  16. Characterization of insoluble organic matter in primitive meteorites by microRaman spectroscopy

    Science.gov (United States)

    Busemann, Henner; Alexander, M. O'd.; Nittler, Larry R.

    2007-08-01

    We have analyzed the chemically and isotopically well-characterized insoluble organic matter (IOM) extracted from 51 unequilibrated chondrites (8 CR, 9 CM, 1 CI, 3 ungrouped C, 9 CO, 9 CV, 10 ordinary, 1 CB and 1 E chondrites) using confocal imaging Raman spectroscopy. The average Raman properties of the IOM, as parameterized by the peak characteristics of the so-called D and G bands, which originate from aromatic C rings, show systematic trends that are correlated with meteorite (sub-) classification and IOM chemical compositions. Processes that affect the Raman and chemical properties of the IOM, such as thermal metamorphism experienced on the parent bodies, terrestrial weathering and amorphization due to irradiation in space, have been identified. We established separate sequences of metamorphism for ordinary, CO, oxidized, and reduced CV chondrites. Several spectra from the most primitive chondrites reveal the presence of organic matter that has been amorphized. This amorphization, usually the result of sputtering processes or UV or particle irradiation, could have occurred during the formation of the organic material in interstellar or protoplanetary ices or, less likely, on the surface of the parent bodies or during the transport of the meteorites to Earth. D band widths and peak metamorphic temperatures are strongly correlated, allowing for a straightforward estimation of these temperatures.

  17. The molecular structure of the insoluble organic matter isolated from Murchison carbonaceous chondrite.

    Science.gov (United States)

    Robert, F.; Derenne, S.

    2009-04-01

    During these last 10 years, our group has characterized the various molecular moieties of the insoluble organic matter (IOM) isolated from carbonaceous meteorites with the aim of reconstructing its overall molecular structure. Indeed, a precise knowledge of the structure of an organic macromolecule contains irreplaceable information that traces its mechanisms of synthesis and its conditions of formation. Such a modelled structure will be presented. Carbonaceous chondrites contain up to 3 wt % of carbon that is under the form of soluble and insoluble fractions. The IOM, which constitutes more than 75 wt% of the bulk organic matter, was isolated from the bulk rock through successive acid dissolutions. The chemical structure of the isolated IOM has been studied by both (1) destructive and (2) non destructive methods. Methods include thermal and chemical degradations followed by GC/MS, spectroscopic techniques (nuclear magnetic resonance, Fourier transform infra red spectroscopy; X-ray absorption near-edge spectroscopy, electron paramagnetic resonance) along with high resolution transmission electron microscopy. Although each technique alone cannot provide definite information on the chemical structure of such a complex material, the combination of the results can be used to reconstruct the molecular structure of the IOM. The proposed structure accounts for all these measured parameters. The details of this structure reveal information of the conditions of its formation in space and allow to discuss the mechanisms of organo-synthesis in the cosmochemical context of the formation of the solar system.

  18. Mass spectral chemical fingerprints reveal the molecular dependence of exhaust particulate matters on engine speeds.

    Science.gov (United States)

    Li, Yi; Zhang, Hua; Zhao, Zongshan; Tian, Yong; Liu, Kun; Jie, Feifan; Zhu, Liang; Chen, Huanwen

    2018-05-01

    Particulate matters (PMs) emitted by automobile exhaust contribute to a significant fraction of the global PMs. Extractive atmospheric pressure chemical ionization mass spectrometry (EAPCI-MS) was developed to explore the molecular dependence of PMs collected from exhaust gases produced at different vehicle engine speeds. The mass spectral fingerprints of the organic compounds embedded in differentially sized PMs (e.g., 0.22-0.45, 0.45-1.00, 1.00-2.00, 2.00-3.00, 3.00-5.00, and 5.00-10.00μm) generated at different engine speeds (e.g., 1000, 1500, 2000, 2500, and 3000r/min) were chemically profiled in the mass range of mass to charge ratio (m/z) 50-800. Organic compounds, including alcohols, aldehydes, and esters, were detected in all the PMs tested, with varied concentration levels for each individual PM sample. At relatively low engine speeds (≤1500r/min), the total amount of organic species embedded in PMs of 0.22-1.00μm was greater than in PMs of other sizes, while more organic species were found in PMs of 5.00-10.00μm at high engine speeds (≥3000r/min), indicating that the organic compounds distributed in different sizes of PMs strongly correlated with the engine speed. The experimental data showed that the EAPCI-MS technique enables molecular characterization of PMs in exhaust, revealing the chemical dependence of PMs on the engine speeds (i.e., the combustion conditions) of automobiles. Copyright © 2017. Published by Elsevier B.V.

  19. Mid-infrared study of the molecular structure variability of insoluble organic matter from primitive chondrites

    Science.gov (United States)

    Orthous-Daunay, F.-R.; Quirico, E.; Beck, P.; Brissaud, O.; Dartois, E.; Pino, T.; Schmitt, B.

    2013-03-01

    Insoluble Organic Matter (IOM) found in primitive meteorites was formed in the Early Solar System and subsequently processed on the parent asteroids. The location, temporal sequence and processes of formation of this IOM are still a matter of debate. In particular, there is no consensus on the actual effect of post-accretional aqueous alteration processes on the chemical composition and structure of IOM. In the most primitive chondrites (types 1 and 2), these alterations have so far been either neglected or generically assigned to oxidation processes induced by fluid circulation. A series of IOM samples extracted from 14 chondrites with extensively documented post-accretional histories have been studied by infrared spectroscopy. Aqueous alteration shows no detectable effect on the chemical composition and structure of IOM within or across chondrite classes. Indeed, the most effective post-accretional process appears to be a high-temperature short-duration heating event and concerns essentially type 2 chondrites. In any case, post-accretional processes cannot account for all the chemical and structural variations of IOM. Chondrites from the CI, CR and CM classes accreted IOM precursors with moderately variable compositions, suggesting a chemical heterogeneity of the protosolar disk. The 3.4 μm band, and possibly its overtones and combinations in the near-infrared range, appear to be tracer(s) of the chemical class and possibly of surface heating processes triggered by impacts.

  20. Visualising the equilibrium distribution and mobility of organic contaminants in soil using the chemical partitioning space.

    Science.gov (United States)

    Wong, Fiona; Wania, Frank

    2011-06-01

    Assessing the behaviour of organic chemicals in soil is a complex task as it is governed by the physical chemical properties of the chemicals, the characteristics of the soil as well as the ambient conditions of the environment. The chemical partitioning space, defined by the air-water partition coefficient (K(AW)) and the soil organic carbon-water partition coefficient (K(OC)), was employed to visualize the equilibrium distribution of organic contaminants between the air-filled pores, the pore water and the solid phases of the bulk soil and the relative importance of the three transport processes removing contaminants from soil (evaporation, leaching and particle erosion). The partitioning properties of twenty neutral organic chemicals (i.e. herbicides, pharmaceuticals, polychlorinated biphenyls and volatile chemicals) were estimated using poly-parameter linear free energy relationships and superimposed onto these maps. This allows instantaneous estimation of the equilibrium phase distribution and mobility of neutral organic chemicals in soil. Although there is a link between the major phase and the dominant transport process, such that chemicals found in air-filled pore space are subject to evaporation, those in water-filled pore space undergo leaching and those in the sorbed phase are associated with particle erosion, the partitioning coefficient thresholds for distribution and mobility can often deviate by many orders of magnitude. In particular, even a small fraction of chemical in pore water or pore air allows for evaporation and leaching to dominate over solid phase transport. Multiple maps that represent soils that differ in the amount and type of soil organic matter, water saturation, temperature, depth of surface soil horizon, and mineral matters were evaluated.

  1. Study on the effect of organic fertilizers on soil organic matter and enzyme activities of soil in forest nursery

    Directory of Open Access Journals (Sweden)

    Piaszczyk Wojciech

    2017-09-01

    Full Text Available The aim of the study was to assess the effects of organic fertilization on selected chemical properties of the soil and the activity of dehydrogenase and β-glucosidase in the soil of forest nursery. The main goal was to evaluate the role of organic fertilizers in carbon storage in the forest nursery soil. Sample plots were located in northern Poland in the Polanów Forest District on a forest nursery. Soil samples were collected from horizon 0–20 cm for laboratory analyzes. In soil samples pH, soil texture, and organic carbon, nitrogen, base cation contents, dehydrogenase activity and β-glucosidase activity were determined. The obtained results were used to evaluate the carbon storage. The results confirm the beneficial effect of the applied organic fertilizer on chemical properties of the soils under study and their biological activity. The applied organic fertilizers had an impact on increased accumulation of soil organic matter. In the soils investigated, there was an increase in the activity of such enzymes as dehydrogenases and β-glucosidase.

  2. Changes in soil organic matter compositrion after introduction of riparian vegetation on shores of hydroelectric reservoires (Southeast of Brazil)

    NARCIS (Netherlands)

    Alcantara, de F.A.; Buurman, P.; Curi, N.; Furtini Neto, A.E.; Lagen, van B.; Meijer, E.M.

    2004-01-01

    This work is part of a research program with the general objective of evaluating soil sustainability in areas surrounding hydroelectric reservoirs, which have been planted with riparian forest. The specific aims were: (i) to assess if and how the soil organic matter (SOM) chemical composition has

  3. Soil organic matter chemistry changes upon secondary succession in Imperata Grasslands , Indonesia: A pyrolysis - GC/MS study

    NARCIS (Netherlands)

    Yassir, I.; Buurman, P.

    2012-01-01

    The chemical composition of soil organic matter (SOM) following secondary succession in Imperata grassland was investigated by Pyrolysis-Gas Chromatography/Mass Spectrometry (GC/MS). We studied 46 samples from different stages of succession using plots that last burned 3 and 9 years previously,

  4. Degradation of mangrove tissues by arboreal termites (Nasutitermes acajutlae) and their role in the mangrove C cycle (Puerto Rico): Chemical characterization and organic matter provenance using bulk δ13C, C/N, alkaline CuO oxidation-GC/MS, and solid-state 13C NMR

    Science.gov (United States)

    Vane, Christopher H.; Kim, Alexander W.; Moss-Hayes, Vicky; Snape, Colin E.; Diaz, Miguel Castro; Khan, Nicole S.; Engelhart, Simon E.; Horton, Benjamin P.

    2013-08-01

    Arboreal termites are wood decaying organisms that play an important role in the first stages of C cycling in mangrove systems. The chemical composition of Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa leaf, stem, and pneumatophore tissues as well as associated sediments was compared to that of nests of the termite Nasutitermes acajutlae. Nests gave δ13C values of -26.1 to -27.2‰ (±0.1) and C/N of 43.3 (±2.0) to 98.6 (±16.2) which were similar to all stem and pneumatophores but distinct from mangrove leaves or sediments. Organic matter processed by termites yielded lignin phenol concentrations (Λ, lambda) that were 2-4 times higher than stem or pneumatophores and 10-20 times higher than that of leaves or sediments, suggesting that the nests were more resistant to biodegradation than the mangrove vegetation source. 13C NMR revealed that polysaccharide content of mangrove tissues (50-69% C) was higher than that of the nests (46-51% C). Conversely, lignin accounted for 16.2-19.6% C of nest material, a threefold increase relative to living mangrove tissues; a similar increase in aromatic methoxyl content was also observed in the nests. Lipids (aliphatic and paraffinic moieties) were also important but rather variable chemical components of all three mangrove species, representing between 13.5 and 28.3% of the C content. Termite nests contained 3.14 Mg C ha-1 which represents approximately 2% of above ground C storage in mangroves, a value that is likely to increase upon burial due to their refractory chemical composition.

  5. Complete and Partial Photo-oxidation of Dissolved Organic Matter Draining Permafrost Soils.

    Science.gov (United States)

    Ward, Collin P; Cory, Rose M

    2016-04-05

    Photochemical degradation of dissolved organic matter (DOM) to carbon dioxide (CO2) and partially oxidized compounds is an important component of the carbon cycle in the Arctic. Thawing permafrost soils will change the chemical composition of DOM exported to arctic surface waters, but the molecular controls on DOM photodegradation remain poorly understood, making it difficult to predict how inputs of thawing permafrost DOM may alter its photodegradation. To address this knowledge gap, we quantified the susceptibility of DOM draining the shallow organic mat and the deeper permafrost layer of arctic soils to complete and partial photo-oxidation and investigated changes in the chemical composition of each DOM source following sunlight exposure. Permafrost and organic mat DOM had similar lability to photomineralization despite substantial differences in initial chemical composition. Concurrent losses of carboxyl moieties and shifts in chemical composition during photodegradation indicated that photodecarboxylation could account for 40-90% of DOM photomineralized to CO2. Permafrost DOM had a higher susceptibility to partial photo-oxidation compared to organic mat DOM, potentially due to a lower abundance of phenolic moieties with antioxidant properties. These results suggest that photodegradation will likely continue to be an important control on DOM fate in arctic freshwaters as the climate warms and permafrost soils thaw.

  6. Fracionamento químico e físico da matéria orgânica de um argissolo vermelho sob diferentes sistemas de uso Physical and chemical fractionation of organic matter of an alfisol under different use systems

    Directory of Open Access Journals (Sweden)

    Daiane Carvalho dos Santos

    2013-05-01

    Full Text Available Objetivou-se com este estudo avaliar o carbono orgânico total e as frações físicas e químicas da matéria orgânica (MO do solo em um Argissolo Vermelho Eutrófico arênico, submetido a diferentes sistemas de uso. Os sistemas de uso do solo avaliados foram: florestamento homogêneo de Eucalyptus grandis (EUC, sistema agrossilvipastoril na faixa (ASP e campo nativo (CN, nas camadas de 0,000-0,025m e de 0,025-0,075m. A fração grosseira (CFG e o carbono associado aos minerais (CAM foram obtidos por meio de fracionamento físico granulométrico. As frações leve livre (FLL, leve oclusa (FLO e pesada (FP foram obtidas por meio de fracionamento físico densimétrico. As frações não húmicas (NH, ácido fúlvico (AF, ácido húmico (AH e humina (HU foram obtidas por meio de fracionamento químico. O sistema EUC promoveu maiores estoques de carbono orgânico total, CFG, FLL e FLO e na fração AF nas camadas avaliadas. Na camada superficial, os mecanismos de proteção da MO por recalcitrância molecular e estabilização química estão sobrepondo a estabilidade decorrente da oclusão em agregados. Com a dificuldade de formar agregados, devido a matrizes arenosas desse solo, o carbono jovem que entra no sistema é decomposto pelos microrganismos, entrando em um estágio mais avançado de decomposição e, nesse caso, formando associações com as partículas silte e argila, mesmo em solos em que o percentual de argila é baixo. Através do fracionamento químico, observou-se que a maior parte da MO do solo encontra-se armazenada na forma de HU.The objective of this study was to evaluate the total organic carbon and the physical and chemical fractions of organic matter in an Alfisol under different use systems. The land use systems evaluated was homogeneous forestry of Eucalyptus grandis, agrosilvopastoral system and native grassland, in layers from 0.000-0.025 and 0.025-0.075m depth. The coarse fraction (CFG and the carbon associated

  7. Molecular building blocks and their architecture in biologically/environmentally compatible soft matter chemical machinery.

    Science.gov (United States)

    Toyota, Taro; Banno, Taisuke; Nitta, Sachiko; Takinoue, Masahiro; Nomoto, Tomonori; Natsume, Yuno; Matsumura, Shuichi; Fujinami, Masanori

    2014-01-01

    This review briefly summarizes recent developments in the construction of biologically/environmentally compatible chemical machinery composed of soft matter. Since environmental and living systems are open systems, chemical machinery must continuously fulfill its functions not only through the influx and generation of molecules but also via the degradation and dissipation of molecules. If the degradation or dissipation of soft matter molecular building blocks and biomaterial molecules/polymers can be achieved, soft matter particles composed of them can be used to realize chemical machinery such as selfpropelled droplets, drug delivery carriers, tissue regeneration scaffolds, protocell models, cell-/tissuemarkers, and molecular computing systems.

  8. Highly Viscous States Affect the Browning of Atmospheric Organic Particulate Matter.

    Science.gov (United States)

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; Bateman, Adam P; Zhang, Yue; Gong, Zhaoheng; Bertram, Allan K; Martin, Scot T

    2018-02-28

    Initially transparent organic particulate matter (PM) can become shades of light-absorbing brown via atmospheric particle-phase chemical reactions. The production of nitrogen-containing compounds is one important pathway for browning. Semisolid or solid physical states of organic PM might, however, have sufficiently slow diffusion of reactant molecules to inhibit browning reactions. Herein, organic PM of secondary organic material (SOM) derived from toluene, a common SOM precursor in anthropogenically affected environments, was exposed to ammonia at different values of relative humidity (RH). The production of light-absorbing organonitrogen imines from ammonia exposure, detected by mass spectrometry and ultraviolet-visible spectrophotometry, was kinetically inhibited for RH atmospheric brown carbon production and associated influences on energy balance.

  9. From Solute, Fluidic and Particulate Precursors to Complex Organizations of Matter.

    Science.gov (United States)

    Rao, Ashit; Cölfen, Helmut

    2018-03-24

    The organization of matter from its constitutive units recruits intermediate states with distinctive degrees of self-association and molecular order. Existing as clusters, droplets, gels as well as amorphous and crystalline nanoparticles, these precursor forms have fundamental contributions towards the composition and structure of inorganic and organic architectures. In this personal account, we show that the transitions from atoms, molecules or ionic species to superstructures of higher order are intertwined with the interfaces and interactions of precursor and intermediate states. Structural organizations distributed across different length scales are explained by the multistep nature of nucleation and crystallization, which can be guided towards functional hybrid materials by the strategic application of additives, templates and reaction environments. Thus, the non-classical pathways for material formation and growth offer conceptual frameworks for elucidating, inducing and directing fascinating material organizations of biogenic and synthetic origins. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Dissolved Organic Matter (DOM) Export from Watersheds to Coastal Oceans

    Science.gov (United States)

    Chen, R. F.; Gardner, G. B.; Peri, F.

    2016-02-01

    Dissolved organic matter (DOM) from terrestrial plants and soils is transported by surface waters and groundwaters to coastal ocean waters. Along the way, photochemical and biological degradation can remove DOM, and in situ processes such as phytoplankton leaching and sediment sources can add to the DOM in the river water. Wetlands, especially coastal wetlands can add significant amounts of DOM that is carried by rivers and is exported through estuaries to coastal systems. We will present observational data from a variety of coastal systems (San Francisco Bay, Boston Harbor, Chesapeake Bay, Hudson River, the Mississippi River, and a small salt marsh in the Gulf of Mexico). High resolution measurements of chromophoric dissolved organic matter (CDOM) can be correlated with dissolved organic carbon (DOC) so can be used to estimate DOC in specific systems and seasons. Gradients in CDOM/DOC combined with water fluxes can be used to estimate DOC fluxes from a variety of coastal watersheds to coastal systems. Influences of land use, system size, residence time, DOM quality, and photochemical and biological degradation will be discussed. The significance of coastal wetlands in the land-to-ocean export of DOC will be emphasized.

  11. Formation and Stability of Microbially Derived Soil Organic Matter

    Science.gov (United States)

    Waldrop, M. P.; Creamer, C.; Foster, A. L.; Lawrence, C. R.; Mcfarland, J. W.; Schulz, M. S.

    2017-12-01

    Soil carbon is vital to soil health, food security, and climate change mitigation, but the underlying mechanisms controlling the stabilization and destabilization of soil carbon are still poorly understood. There has been a conceptual paradigm shift in how soil organic matter is formed which now emphasizes the importance of microbial activity to build stable (i.e. long-lived) and mineral-associated soil organic matter. In this conceptual model, the consumption of plant carbon by microorganisms, followed by subsequent turnover of microbial bodies closely associated with mineral particles, produces a layering of amino acid and lipid residues on the surfaces of soil minerals that remains protected from destabilization by mineral-association and aggregation processes. We tested this new model by examining how isotopically labeled plant and microbial C differ in their fundamental stabilization and destabilization processes on soil minerals through a soil profile. We used a combination of laboratory and field-based approaches to bridge multiple spatial scales, and used soil depth as well as synthetic minerals to create gradients of soil mineralogy. We used Raman microscopy as a tool to probe organic matter association with mineral surfaces, as it allows for the simultaneous quantification and identification of living microbes, carbon, minerals, and isotopes through time. As expected, we found that the type of minerals present had a strong influence on the amount of C retained, but the stabilization of new C critically depends on growth, death, and turnover of microbial cells. Additionally, the destabilization of microbial residue C on mineral surfaces was little affected by flushes of DOC relative to wet-dry cycles alone. We believe this new insight into microbial mechanisms of C stabilization in soils will eventually lead to new avenues for measuring and modeling SOM dynamics in soils, and aid in the management of soil C to mediate global challenges.

  12. Mercury dilution by autochthonous organic matter in a fertilized mangrove wetland.

    Science.gov (United States)

    Machado, Wilson; Sanders, Christian J; Santos, Isaac R; Sanders, Luciana M; Silva-Filho, Emmanoel V; Luiz-Silva, Wanilson

    2016-06-01

    A dated sediment core from a highly-fertilized mangrove wetland located in Cubatão (SE Brazil) presented a negative correlation between mercury (Hg) and organic carbon contents. This is an unusual result for a metal with well-known affinity to organic matter. A dilution of Hg concentrations by autochthonous organic matter explained this observation, as revealed by carbon stable isotopes signatures (δ(13)C). Mercury dilution by the predominant mangrove-derived organic matter counterbalanced the positive influences of algal-derived organic matter and clay contents on Hg levels, suggesting that deleterious effects of Hg may be attenuated. Considering the current paradigm on the positive effect of organic matter on Hg concentrations in coastal sediments and the expected increase in mangrove organic matter burial due to natural and anthropogenic stimulations of primary production, predictions on the influences of organic matter on Hg accumulation in mangrove wetlands deserve caution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Global contamination trends of persistent organic chemicals

    National Research Council Canada - National Science Library

    Loganathan, Bommanna G; Lam, Paul K. S

    2012-01-01

    "Composed by a diverse group of experts, this reference covers the history, present status, and projected future trends of environmental contamination from highly toxic synthetic chemical pollutants...

  14. Persistence of soil organic matter as an ecosystem property

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M.W.; Torn, M. S.; Abiven, S.; Dittmar, T.; Guggenberger, G.; Janssens, I.A.; Kleber, M.; Kögel-Knabner, I.; Lehmann, J.; Manning, D.A.C.; Nannipieri, P.; Rasse, D.P.; Weiner, S.; Trumbore, S.E.

    2011-08-15

    Globally, soil organic matter (SOM) contains more than three times as much carbon as either the atmosphere or terrestrial vegetation. Yet it remains largely unknown why some SOM persists for millennia whereas other SOM decomposes readily—and this limits our ability to predict how soils will respond to climate change. Recent analytical and experimental advances have demonstrated that molecular structure alone does not control SOM stability: in fact, environmental and biological controls predominate. Here we propose ways to include this understanding in a new generation of experiments and soil carbon models, thereby improving predictions of the SOM response to global warming.

  15. Aquatic Organic Matter Fluorescence - from phenomenon to application

    Science.gov (United States)

    Reynolds, Darren

    2014-05-01

    The use of fluorescence to quantify and characterise aquatic organic matter in river, ocean, ground water and drinking and waste waters has come along way since its discovery as a phenomenon in the early 20th century. For example, there are over 100 papers published each year in international peer reviewed journals, an order of magnitude increase since a decade ago (see Figure taken from ISI database from 1989 to 2007 for publications in the fields of river water and waste water). Since then it has been extensively used as a research tool since the 1990's by scientists and is currently used for a wide variety of applications within a number of sectors. Universities, organisations and companies that research into aquatic organic matter have either recently readily use appropriate fluorescence based techniques and instrumentation. In industry and government, the technology is being taken up by environmental regulators and water and wastewater companies. This keynote presentation will give an overview of aquatic organic matter fluorescence from its conception as a phenomenon through to its current use in a variety of emerging applications within the sectors concerned with understanding, managing and monitoring the aquatic environment. About the Speaker Darren Reynolds pioneered the use of fluorescence spectroscopy for the analysis of wastewaters in the 1990's. He currently leads a research group within the Centre for Research in Biosciences and sits on the Scientific Advisory Board for the Institute of Bio-Sensing Technology at the University of the West of England, Bristol. He is a multidisciplinary scientist concerned with the development of technology platforms for applications in the fields of environment/agri-food and health. His current research interests include the development of optical technologies and techniques for environmental and biological sensing and bio-prospecting applications. He is currently involved in the development and use of synthetic biology

  16. Controlled experimental soil organic matter modification for study of organic pollutant interactions in soil

    International Nuclear Information System (INIS)

    Ahmed, Ashour A.; Kühn, Oliver; Leinweber, Peter

    2012-01-01

    Interactions of organic pollutants with soil organic matter can be studied by adsorption of the pollutants on well-characterized soil samples with constant mineralogy but different organic matter compositions. Therefore, the objectives of the current study are establishing a set of different, well-characterized soil samples by systematic modifications of their organic matter content and molecular composition and prove these modifications by advanced complementary analytical techniques. Modifications were done by off-line pyrolysis and removal/addition of hot-water extracted organic fraction (HWE) from/to the original soil sample. Both pyrolysis-field ionization mass spectrometry (Py-FIMS) and synchrotron-based C- and N- X-ray absorption near-edge structure spectroscopy (XANES) were applied to investigate the composition of the soil organic matter. These complementary analytical methods in addition to elemental analysis agreed in showing the following order of organic matter contents: pyrolyzed soil < soil residue < original soil < soil + 3 HWE < soil + 6 HWE < HWE. The addition of HWE to the soil sample increases the relative proportions of carbohydrates, N-containing heterocyclic compounds and peptides, and decreases the relative proportions of phenols, lignin monomers and dimers, and lipids. The most abundant organic compound classes in the pyrolyzed sample are aromatics, aliphatic nitriles, aldehydes, five- and six-membered N-containing heterocyclic compounds, and aliphatic carboxylic acids. It can be expected that removal or addition of HWE, that mimic biomass inputs to soil or soil amendments, change the binding capacity for organic pollutants less intensively than heat impact, e.g. from vegetation burning. It will be possible to interpret kinetic data on the pollutants adsorption by these original and modified soil samples on the basis of the bond- and element-specific speciation data through C-XANES and N-XANES and the molecular-level characterization

  17. Structure and organic matter under different soil management conditions in the center of Argentina

    International Nuclear Information System (INIS)

    Bricchi, E.

    2004-01-01

    In Central Argentina, Cordoba Province, as in different parts of the world, the equilibrium state of soil under natural condition has been modified by both the replacement of natural vegetation and by tillage. With time, these two disturbing factors have led to a new soil state whose main characteristic is an important decrease of chemical, physical and biological soil functions. The degree of these changes is directly related to soil resistance according to soil genesis. The soil organic matter and the structure of the superficial profile of soil are suitable indicators mainly for physical functions. Recently, it became necessary to look for a combination of technologies leading to an energy input throughout conservation tillage systems, soil covering and agro-chemicals which tend to improve soil quality in order to obtain a sustainable production. The removal of natural vegetation and tillage systems have caused the following effects on the first centimetres of soils: A 77 to 80% loss of organic matter during a period of about 80 years. Changes in the water stable aggregates distribution. A 77% loss of large aggregates and a 55% gain of fine aggregates. Our results would indicate that the disturbance level was higher to the natural resistance of soil. The organic carbon content in the first centimetres of soil is increased when all crop stubble remains on the field and conservationist tillage is applied. Conservation tillages are more efficient in the lower position of relief, meaning the beginning of a change of organic matter tendency that would possibly tend to new equilibrium state. On the other hand, the percentage of water stable aggregates would also be increased as consequence of a higher organic carbon content

  18. Photochemical Reactions of Particulate Organic Matter: Deciphering the Role of Direct and Indirect Processes

    Science.gov (United States)

    Carrasquillo, A. J.; Gelfond, C. E.; Kocar, B. D.

    2016-12-01

    Photochemical reactions of natural organic matter (NOM) represent potentially important pathways for biologically recalcitrant material to be chemically altered in aquatic systems. Irradiation can alter the physical state of organic matter by facilitating the cycling between the particulate (POM) and dissolved (DOM) pools, however, a molecular level understanding of this chemically dynamic system is currently lacking. Photochemical reactions of a target molecule proceed by the direct absorption of a photon, or through reaction with a second photolytically generated species (i.e. the hydroxyl radical, singlet oxygen, excited triplet state NOM, hydrogen peroxide, etc.). Here, we isolate the major direct and indirect photochemical reactions of a lignocellulose-rich POM material (Phragmites australis) to determine their relative importance in changing the the chemical structure of the parent POM, and in the production of DOM. We measured POM molecular structure using a combination of NMR and FTIR for bulk analyses and scanning transmission x-ray microscopy (STXM) for spatially resolved chemistry, while the chemical composition of photo-produced DOM was measured using ultra-high resolution mass spectrometry. Results are discussed in the context of the differences in chemical composition of both NOM pools resulting from the isolated photochemical pathways. All treatments result in an increase in DOM with reaction time, indicating that the larger POM matrix is likely fragmenting into smaller more soluble species. Spectroscopic measurements, on the other hand, point to functionalization reactions which increase the abundance of alcohol, acid, and carbonyl moieties in both carbon pools. This unique dataset provides new insight into how photochemical reactions alter the chemical composition of NOM while highlighting the relative importance of indirect pathways.

  19. Linking geochemical processes in mud volcanoes with arsenic mobilization driven by organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chia-Chuan; Kar, Sandeep [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Jean, Jiin-Shuh, E-mail: jiinshuh@mail.ncku.edu.tw [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Wang, Chung-Ho [Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan (China); Lee, Yao-Chang [National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan (China); Sracek, Ondra [OPV s.r.o. (Groundwater Protection Ltd.), Bělohorská 31, 169 00 Praha 6 (Czech Republic); Department of Geology, Faculty of Science, Palacký University, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Li, Zhaohui [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Department of Geosciences, University of Wisconsin – Parkside, Kenosha, WI 53144 (United States); Bundschuh, Jochen [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Faculty of Engineering and Surveying and National Centre for Engineering in Agriculture, The University of Southern Queensland, Toowoomba (Australia); Yang, Huai-Jen [Department of Earth Sciences, National Cheng Kung University, Tainan, Taiwan (China); Chen, Chien-Yen [Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi 621, Taiwan (China)

    2013-11-15

    Highlights: ► Study represents geochemical characteristics and their spatial variability among six mud volcanoes of southern Taiwan. ► Anoxic mud volcanic fluids containing high NaCl imply connate water as the possible source. ► δ{sup 18}O-rich fluids is associated with silicate and carbonate mineral released through water–rock interaction. ► High As content in mud and its sequential extraction showed mostly adsorbed As on organic and sulphidic phases. ► Organic matter specially humic acid showed redox dependence and it may play an important role in binding and mobility of arsenic. -- Abstract: The present study deals with geochemical characterization of mud fluids and sediments collected from Kunshuiping (KSP), Liyushan (LYS), Wushanting (WST), Sinyangnyuhu (SYNH), Hsiaokunshui (HKS) and Yenshuikeng (YSK) mud volcanoes in southwestern Taiwan. Chemical constituents (cations, anions, trace elements, organic carbon, humic acid, and stable isotopes) in both fluids and mud were analyzed to investigate the geochemical processes and spatial variability among the mud volcanoes under consideration. Analytical results suggested that the anoxic mud volcanic fluids are highly saline, implying connate water as the probable source. The isotopic signature indicated that δ{sup 18}O-rich fluids may be associated with silicate and carbonate mineral released through water–rock interaction, along with dehydration of clay minerals. Considerable amounts of arsenic in mud irrespective of fluid composition suggested possible release through biogeochemical processes in the subsurface environment. Sequential extraction of As from the mud indicated that As was mostly present in organic and sulphidic phases, and adsorbed on amorphous Mn oxyhydroxides. Volcanic mud and fluids are rich in organic matter (in terms of organic carbon), and the presence of humic acid in mud has implications for the binding of arsenic. Functional groups of humic acid also showed variable sources of

  20. The Physics of Life. Part I: The Animate Organism as an Active Condensed Matter Body

    OpenAIRE

    Kukuruznyak , Dmitry ,

    2017-01-01

    Nonequilibrium "active agents" establish bonds with each other and create a quickly evolving condensed state known as active matter. Recently, active matter composed of motile self-organizing biopolymers demonstrated a biotic-like motion similar to cytoplasmic streaming. It was suggested that the active matter could produce cells. However, active matter physics cannot yet define an " organism " and thus make a satisfactory connection to biology. This paper describes an organism made of active...

  1. Accretion and Preservation of Organic Matter in Carbonaceous Chondrites as Revealed by NanoSIMS Imaging.

    Science.gov (United States)

    Remusat, L.; Guan, Y.; Eiler, J.

    2008-12-01

    Carbonaceous chondrites are the most primitive known meteorites. Their parent bodies accreted several discrete components of the early solar system: CAIs, other silicates, oxides, sulfides, ice, organics, and noble gases. Radioactive decay of short live radionucleides quickly heated these parent bodies and drove thermal metamorphism and aqueous alteration of their constituents. Despite this post-acretionary modification, at least some components of the organic matter in the carbaceous chondrites retained distinctive isotopic and molecular properties that may relate to their pre-acretionary origins in the protosolar nebula or in the molecular cloud that gave birth to it [1]. These processes that gave rise to early solar-system organic matter and the extent to which it was modified by parent body processes are still a matter of debate [2]. We have acquired NanoSIMS images of matrices of several CI, CM, CR and CV chondrites to document, in- situ, the distribution of organics and their textural and chemical relationships to co-existing inorganic components. Importantly, we performed these analyses on essentially unmodified fragments of matrix material pressed into indium, rather than on extracts, which have been the focus of most previous work on meteoritic organic matter. Specifically, we simultaneously collected H, D, 12C, 18O, 26CN, 28Si and 32S with a spatial resolution of 200 nm. Inorganic constituents of the imaged domains were determined by SEM imaging and EDS analysis. We identify two textural classes of organic constituents: diffuse organic matter and organic particles ~ 1 micron in diameter. The particles are common and do not exhibit any textural association with any inorganic matrix constituent. This distribution is consistent with previous observations by fluorescence optical microscopy [3]. These organic particles are likely primarily composed of insoluble organic matter (IOM) that grew prior to accretion as pure organic particules and was preserved in

  2. Can particulate organic matter reveal emerging changes in soil organic carbon?

    DEFF Research Database (Denmark)

    Simonsson, Magnus; Kirchmann, Holger; Magid, Jakob

    2014-01-01

    different cropping systems, N fertilizer applications, and organic amendments, we found that C and N in the fine to medium sand fraction (0.063-0.600 mm, "Fraction B") showed considerably larger relative errors according to ANOVA (RMSE was 11-20% of the mean), slightly lower values of the F statistic......This study assessed whether particulate organic matter (POM) in sand fractions, isolated by wet sieving after treatment with Na hexametaphosphate, can be a sensitive indicator of incipient changes in the content and composition of soil organic matter. In five long-term field experiments including......, and slightly less contrast between treatments than total organic C and N (RMSE 3-9% of the mean). Imprecision in laboratory procedures only explained part of the increase in RMSE for C and N in Fraction B compared with total C and N; within-field spatial variability most likely had a greater influence...

  3. [Vermicomposting of different organic materials and three-dimensional excitation emission matrix fluorescence spectroscopic characterization of their dissolved organic matter].

    Science.gov (United States)

    Yang, Wei; Wang, Dong-sheng; Liu, Man-qiang; Hu, Feng; Li, Hui-xin; Huang, Zhong-yang; Chang, Yi-jun; Jiao, Jia-guo

    2015-10-01

    In this experiment, different proportions of the cattle manure, tea-leaf, herb and mushroom residues, were used as food for earthworm (Eisenia fetida) to study the growth of the earth-worm. Then the characteristics and transformation of nutrient content and three-dimensional excitation emission matrix fluorescence (3DEEM) of dissolved organic matter (DOM) during vermistabilization were investigated by means of chemical and spectroscopic methods. The result showed that the mixture of different ratios of cattle manure with herb residue, and cattle manure with tea-leaf were conducive to the growth of earthworm, while the materials compounded with mushroom residue inhibited the growth of earthworm. With the increasing time of verimcomposting, the pH in vermicompost tended to be circumneutral and weakly acidic, and there were increases in electrical conductivity, and the contents of total nitrogen, total phosphorus, available nitrogen, and available phosphorus, while the total potassium and available potassium increased first and then decreased, and the organic matter content decreased. 3DEEM and fluorescence regional integration results indicated that, the fluorescence of protein-like fluorescence peaks declined significantly, while the intensity of humic-like fluorescence peak increased significantly in DOM. Vermicomposting process might change the compositions of DOM with elevated concentrations of humic acid and fulvic acid in the organics. In all, this study suggested the suitability of 3DEEM for monitoring the organics transformation and assessing the maturity in the vermicomposting.

  4. Sea cucumbers reduce chromophoric dissolved organic matter in aquaculture tanks

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Sadeghi-Nassaj

    2018-02-01

    Full Text Available Background Mono-specific aquaculture effluents contain high concentrations of nutrients and organic matter, which affect negatively the water quality of the recipient ecosystems. A fundamental feature of water quality is its transparency. The fraction of dissolved organic matter that absorbs light is named chromophoric dissolved organic matter (CDOM. A sustainable alternative to mono-specific aquaculture is the multitrophic aquaculture that includes species trophically complementary named “extractive” species that uptake the waste byproducts. Sea cucumbers are recognized as efficient extractive species due to the consumption of particulate organic matter (POM. However, the effects of sea cucumbers on CDOM are still unknown. Methods During more than one year, we monitored CDOM in two big-volume tanks with different trophic structure. One of the tanks (−holothurian only contained around 810 individuals of Anemonia sulcata, whereas the other tank (+holothurian also included 90 individuals of Holothuria tubulosa and Holothuria forskali. We routinely analyzed CDOM absorption spectra and determined quantitative (absorption coefficients at 325 nm and qualitative (spectral slopes optical parameters in the inlet waters, within the tanks, and in their corresponding effluents. To confirm the time-series results, we also performed three experiments. Each experiment consisted of two treatments: +holothurians (+H and –holothurians (−H. We set up three +H tanks with 80 individuals of A. sulcata and 10 individuals of H. tubulosa in each tank and four –H tanks that contained only 80 individuals of A. sulcata. Results In the time-series, absorption coefficients at 325 nm (a325 and spectral slopes from 275 to 295 nm (S275−295 were significantly lower in the effluent of the +holothurian tank (average: 0.33 m−1 and 16 µm−1, respectively than in the effluent of the −holothurian tank (average: 0.69 m−1 and 34 µm−1, respectively, the former

  5. The Preservation and Detection of Organic Matter within Jarosite

    Science.gov (United States)

    Lewis, J. M. T.; Eigenbrode, J. L.; McAdam, A.; Andrejkovicova, S. C.; Knudson, C. A.; Wong, G. M.; Millan, M.; Freissinet, C.; Szopa, C.; Li, X.; Bower, D. M.

    2017-12-01

    Since its arrival at Mt. Sharp in 2014 the Mars Science Laboratory Curiosity rover has been examining the mountain's lower stratigraphy, which shows a progression from clay-bearing to sulfate-bearing strata. Clay minerals are known to be effective long-term preservers of organic matter [1], but it is important to also consider the potential for Martian sulfate minerals to host organic molecules. The Sample Analysis at Mars (SAM) instrument suite on board the rover uses pyrolysis to liberate organic fragments from sampled materials [2]. However, the surface of Mars hosts widespread oxychlorine phases, which thermally decompose to release oxygen and chlorine that can degrade and destroy organic signals [3]. Francois et al. (2016) demonstrated that synthetic magnesium sulfate can incorporate phthalic acid and protect it from oxychlorine phases during pyrolysis [4]. Magnesium sulfate as well as calcium sulfate and jarosite have all been observed by instruments on the rover. The addition of organic standards to the starting materials in jarosite synthesis reactions has conclusively demonstrated that jarosite can incorporate organic molecules. The samples were analyzed by SAM-like evolved gas analysis (EGA) and gas chromatography-mass spectrometry (GC-MS) and the influence of perchlorates assessed. Jarosite has been observed by multiple missions to the Martian surface and from orbit, thus the probability of future organic detection missions encountering the mineral is high. Samples from this study were examined by laser desorption/ionization mass spectrometry and Raman spectroscopy, which will be utilized by the ExoMars rover and Mars 2020 rover respectively. The data inform the sampling and analysis strategies for sulfate-rich regions of Mars for present and future organic-detection missions. [1] Farmer & Des Marais (1999) JGR: Planets 104, [2] Mahaffy et al., (2012) Space Science Reviews 170 [3] Glavin et al., (2013) JGR: Planets 118 [4] Francois et al., (2016) JGR

  6. Production of fluorescent dissolved organic matter in Arctic Ocean sediments

    Science.gov (United States)

    Chen, Meilian; Kim, Ji-Hoon; Nam, Seung-Il; Niessen, Frank; Hong, Wei-Li; Kang, Moo-Hee; Hur, Jin

    2016-12-01

    Little is known about the production of fluorescent dissolved organic matter (FDOM) in the anoxic oceanic sediments. In this study, sediment pore waters were sampled from four different sites in the Chukchi-East Siberian Seas area to examine the bulk dissolved organic carbon (DOC) and their optical properties. The production of FDOM, coupled with the increase of nutrients, was observed above the sulfate-methane-transition-zone (SMTZ). The presence of FDOM was concurrent with sulfate reduction and increased alkalinity (R2 > 0.96, p  0.95, p CDOM and FDOM to the overlying water column, unearthing a channel of generally bio-refractory and pre-aged DOM to the oceans.

  7. Literature review of organic matter transport from marshes

    Science.gov (United States)

    Dow, D. D.

    1982-01-01

    A conceptual model for estimating a transport coefficient for the movement of nonliving organic matter from wetlands to the adjacent embayments was developed in a manner that makes it compatible with the Earth Resources Laboratory's Productive Capacity Model. The model, which envisages detritus movement from wetland pixels to the nearest land-water boundary followed by movement within the water column from tidal creeks to the adjacent embayment, can be transposed to deal with only the interaction between tidal water and the marsh or to estimate the transport from embayments to the adjacent coastal waters. The outwelling hypothesis postulated wetlands as supporting coastal fisheries either by exporting nutrients, such as inorganic nitrogen, which stimulated the plankton-based grazing food chain in the water column, or through the export of dissolved and particulate organic carbon which provided a benthic, detritus-based food web which provides the food source for the grazing food chain in a more indirect fashion.

  8. Morphological Study of Insoluble Organic Matter Residues from Primitive

    Science.gov (United States)

    Changela, H. G.; Stroud, R. M.; Peeters, Z.; Nittler, L. R.; Alexander, C. M. O'D.; DeGregorio, B. T.; Cody, G. D.

    2012-01-01

    Insoluble organic matter (IOM) constitutes a major proportion, 70-99%, of the total organic carbon found in primitive chondrites [1, 2]. One characteristic morphological component of IOM is nanoglobules [3, 4]. Some nanoglobules exhibit large N-15 and D enrichments relative to solar values, indicating that they likely originated in the ISM or the outskirts of the protoplanetary disk [3]. A recent study of samples from the Tagish Lake meteorite with varying levels of hydrothermal alteration suggest that nanoglobule abundance decreases with increasing hydrothermal alteration [5]. The aim of this study is to further document the morphologies of IOM from a range of primitive chondrites in order to determine any correlation of morphology with petrographic grade and chondrite class that could constrain the formation and/or alteration mechanisms.

  9. Coarse Particulate Organic Matter: Storage, Transport, and Retention

    Energy Technology Data Exchange (ETDEWEB)

    Tiegs, Scott [Oakland University, Rochester, MI; Lamberti, Gary A. [University of Notre Dame, IN; Entrekin, Sally A. [University of Central Arkansas; Griffiths, Natalie A. [ORNL

    2017-08-01

    Coarse particulate organic matter, or CPOM, is a basal energy and nutrient resource in many stream ecosystems and is provided by inputs from the riparian zone, incoming tributaries, and to a lesser extent from in-stream production. The ability of a stream to retain CPOM or slow its transport is critical to its consumption and assimilation by stream biota. In this chapter, we describe basic exercises to measure (1) the amount of CPOM in the streambed and (2) the retention of CPOM from standardized particle releases. We further describe advanced exercises that (1) experimentally enhance the retentiveness of a stream reach and (2) measure organic carbon transport and turnover (i.e., spiraling) in the channel.

  10. Coarse Particulate Organic Matter: Storage, Transport, and Retention

    Energy Technology Data Exchange (ETDEWEB)

    Tiegs, Scott [Oakland University, Rochester, MI; Lamberti, Gary A. [University of Notre Dame, IN; Entrekin, Sally A. [University of Central Arkansas; Griffiths, Natalie A. [ORNL

    2017-06-01

    Coarse particulate organic matter, or CPOM, is a basal energy and nutrient resource in many stream ecosystems and is provided by inputs from the riparian zone, incoming tributaries, and to a lesser extent from in-stream production. The ability of a stream to retain CPOM or slow its transport is critical to its consumption and assimilation by stream biota. In this chapter, we describe basic exercises to measure (1) the amount of CPOM in the streambed and (2) the retention of CPOM from standardized particle releases. We further describe advanced exercises that (1) experimentally enhance the retentiveness of a stream reach and (2) measure organic carbon transport and turnover (i.e., spiraling) in the channel.

  11. Extractability of water-soluble soil organic matter as monitored by spectroscopic and chromatographic analyses.

    Science.gov (United States)

    Nkhili, Ezzhora; Guyot, Ghislain; Vassal, Nathalie; Richard, Claire

    2012-07-01

    Cold and hot water processes have been intensively used to recover soil organic matter, but the effect of extraction conditions on the composition of the extracts were not well investigated. Our objective was to optimize the extraction conditions (time and temperature) to increase the extracted carbon efficiency while minimizing the possible alteration of water extractable organic matter of soil (WEOM). WEOM were extracted at 20°C, 60°C, or 80°C for 24 h, 10-60 min, and 20 min, respectively. The different processes were compared in terms of pH of suspensions, yield of organic carbon, spectroscopic properties (ultraviolet-visible absorption and fluorescence), and by chromatographic analyses. For extraction at 60°C, the time 30 min was optimal in terms of yield of organic carbon extracted and concentration of absorbing and fluorescent species. The comparison of WEOM 20°C, 24 h; 60°C, 30 min; and 80°C, 20 min highlighted significant differences. The content of total organic carbon, the value of specific ultraviolet absorbance (SUVA(254)), the absorbance ratio at 254 and 365 nm (E (2)/E (3)), and the humification index varied in the order: WEOM (20°C, 24 h) < WEOM (80°C, 20 min) < WEOM (60°C, 30 min). The three WEOM contained common fluorophores associated with simple aromatic structures and/or fulvic-like and common peaks of distinct polarity as detected by ultra performance liquid chromatography. For the soil chosen, extraction at 60°C for 30 min is the best procedure for enrichment in organic chemicals and minimal alteration of the organic matter.

  12. Investigation of water-soluble organic matter extracted from shales during leaching experiments

    Science.gov (United States)

    Zhu, Yaling; Vieth-Hillebrand, Andrea; Wilke, Franziska D. H.; Horsfield, Brian

    2017-04-01

    The huge volumes and unknown composition of flowback and produced waters cause major public concerns about the environmental and social compatibility of hydraulic fracturing and the exploitation of gas from unconventional reservoirs. Flowback and produced waters contain not only residues of fracking additives but also chemical species that are dissolved from the shales themselves during fluid-rock interaction. Knowledge of the composition, size and structure of dissolved organic carbon (DOC) as well as the main controls on the release of DOC are a prerequisite for a better understanding of these interactions and its effects on composition of flowback and produced water. Black shales from four different geological settings and covering a maturity range Ro = 0.3-2.6% were extracted with deionized water. The DOC yields were found to decrease rapidly with increasing diagenesis and remain low throughout catagenesis. Four DOC fractions have been qualitatively and quantitatively characterized using size-exclusion chromatography. The concentrations of individual low molecular weight organic acids (LMWOA) decrease with increasing maturity of the samples except for acetate extracted from the overmature Posidonia shale, which was influenced by hydrothermal brines. The oxygen content of the shale organic matter also shows a significant influence on the release of organic acids, which is indicated by the positive trend between oxygen index (OI) and the concentrations of formate and acetate. Based on our experiments, both the properties of the organic matter source and the thermal maturation progress of the shale organic matter significantly influence the amount and quality of extracted organic compounds during the leaching experiments.

  13. Analysis of the organic matter which are present in solid organic wastes from urban areas

    International Nuclear Information System (INIS)

    Canellas, Luciano Pasqualoto; Santos, Gabriel de Araujo; Amarai Sobrinho, Nelson Moura Brasil do; Mazur, Nelson; Moraes, Anselmo Alpande

    1997-01-01

    This study analyses the organic matter which are present in the solid wastes from the Rio de Janeiro city - Brazil. The humic acids were extracted and purified. After the purification, the humic acids were dried by lyophilization. Visible UV, infrared and NMR spectra were obtained for the humic acids extracted

  14. Preservation of organic matter in nontronite against iron redox cycling.

    Science.gov (United States)

    Zeng, Q.

    2015-12-01

    It is generally believed that clay minerals can protect organic matter from degradation in redox active environments, but both biotic and abiotic factors can influence the redox process and thus potentially change the clay-organic associations. However, the specific mechanisms involved in this process remain poorly understood. In this study, a model organic compound, 12-Aminolauric acid (ALA) was selected to intercalate into the structural interlayer of nontronite (an iron-rich smectite, NAu-2) to form an ALA-intercalated NAu-2 composite (ALA-NAu-2). Shawanella putrefaciens CN32 and sodium dithionite were used to reduce structural Fe(III) to Fe(II) in NAu-2 and ALA-NAu-2. The bioreduced ALA-NAu-2 was subsequently re-oxidized by air. The rates and extents of bioreduction and air re-oxidation were determined with wet chemistry methods. ALA release from ALA-NAu-2 via redox process was monitored. Mineralogical changes after iron redox cycle were investigated with X-ray diffraction, infrared spectroscopy, and scanning and transmission electron microscopy. At the beginning stage of bioreduction, S. putrefaciens CN32 reduced Fe(III) from the edges of nontronite and preferentially reduced and dissolved small and poorly crystalline particles, and released ALA, resulting a positive correlation between ALA release and iron reduction extent (80%). Because bacteria are the principal agent for mediating redox process in natural environments, our results demonstrated that the structural interlayer of smectite can serve as a potential shelter to protect organic matter from oxidation.

  15. Organic matter turnover in subsoils: current knowledge and future challenges

    Science.gov (United States)

    Marschner, Bernd

    2014-05-01

    In the past, carbon flux measurements and modelling have mostly considered the topsoil where C-concentrations, root densities and microbial activities are generally highest. However, depending on climate zone and land use, this soil compartment contains only 30-50% of the C-stocks of the first meter. If the deeper subsoil down to 3 m is also considered, the contribution of topsoil carbon stocks to total soil C-pools is only 20-40%. Another distinct property of subsoil organic matter is its high apparent 14C age. The 14C age of bulk soil organic matter below 30 cm depth generally increases continuously indicating mean residence times of several 103 to 104 years. Large pool size and high radiocarbon age suggest that subsoil OM has accumulated at very low rates over very long time periods and therefore appears to be very stable. In this review, several hypotheses for explaining why subsoil SOM is so seemingly old and inert are presented. These questions are being addressed in a recently granted German research unit consisting of 9 subprojects from all soil science disciplines using field measurements of C-fluxes, 14C analyses and conducting field and lab experiments.

  16. Use of native aquatic macrophytes in the reduction of organic matter from dairy effluents.

    Science.gov (United States)

    Queiroz, Rita de Cássia Souza de; Andrade, Rodrigo Santos; Dantas, Isadora Rosário; Ribeiro, Vinícius de Souza; Neto, Luciano Brito Rodrigues; Almeida Neto, José Adolfo de

    2017-08-03

    Considering the diversity and the unexplored potential of regional aquatic flora, this study aimed to identify and analyze the potential of native aquatic macrophytes to reduce the organic matter of dairy wastewater (DW) using experimental constructed wetlands. The dairy wastewater (DW) had an average chemical oxygen demand (COD) of 7414.63 mg/L and then was diluted to 3133.16 mg/L (D1) and to 2506.53 mg/L (D2). Total solids, COD, temperature, and pH analyses were performed, and the biochemical oxygen demand (BOD) was estimated from the COD values. The best performance in the reduction of the organic matter was observed for Polygonum sp. (87.5% COD and 79.6% BOD) and Eichhornia paniculata (90% COD and 83.7% BOD) at dilution D1, on the 8th day of the experiment. However, the highest total solids removal was observed for Polygonum sp. (32.2%), on the 4th day, at dilution D2. The total solid (TS) concentration has also increased starting from the 8th day of the experiment was observed which may have been due to the development of mosquito larvae and their mechanical removal by sieving, thus changing the steady state of the experimental systems. The macrophytes Polygonum sp. and E. paniculata were considered suitable for the reduction of organic matter of DW using constructed wetlands.

  17. Influence of humified organic matter on copper behavior in acid polluted soils

    International Nuclear Information System (INIS)

    Fernandez-Calvino, D.; Soler-Rovira, P.; Polo, A.; Arias-Estevez, M.; Plaza, C.

    2010-01-01

    The main purpose of this work was to identify the role of soil humic acids (HAs) in controlling the behavior of Cu(II) in vineyard soils by exploring the relationship between the chemical and binding properties of HA fractions and those of soil as a whole. The study was conducted on soils with a sandy loam texture, pH 4.3-5.0, a carbon content of 12.4-41.0 g kg -1 and Cu concentrations from 11 to 666 mg kg -1 . The metal complexing capacity of HA extracts obtained from the soils ranged from 0.69 to 1.02 mol kg -1 , and the stability constants for the metal ion-HA complexes formed, log K, from 5.07 to 5.36. Organic matter-quality related characteristics had little influence on Cu adsorption in acid soils, especially if compared with pH, the degree of Cu saturation and the amount of soil organic matter. - The effect of organic matter quality on Cu adsorption in acid soils was low compared with other soil characteristics such as pH or degree of Cu saturation.

  18. Organic matter composition of soil macropore surfaces under different agricultural management practices

    Science.gov (United States)

    Glæsner, Nadia; Leue, Marin; Magid, Jacob; Gerke, Horst H.

    2016-04-01

    Understanding the heterogeneous nature of soil, i.e. properties and processes occurring specifically at local scales is essential for best managing our soil resources for agricultural production. Examination of intact soil structures in order to obtain an increased understanding of how soil systems operate from small to large scale represents a large gap within soil science research. Dissolved chemicals, nutrients and particles are transported through the disturbed plow layer of agricultural soil, where after flow through the lower soil layers occur by preferential flow via macropores. Rapid movement of water through macropores limit the contact between the preferentially moving water and the surrounding soil matrix, therefore contact and exchange of solutes in the water is largely restricted to the surface area of the macropores. Organomineral complex coated surfaces control sorption and exchange properties of solutes, as well as availability of essential nutrients to plant roots and to the preferentially flowing water. DRIFT (Diffuse Reflectance infrared Fourier Transform) Mapping has been developed to examine composition of organic matter coated macropores. In this study macropore surfaces structures will be determined for organic matter composition using DRIFT from a long-term field experiment on waste application to agricultural soil (CRUCIAL, close to Copenhagen, Denmark). Parcels with 5 treatments; accelerated household waste, accelerated sewage sludge, accelerated cattle manure, NPK and unfertilized, will be examined in order to study whether agricultural management have an impact on the organic matter composition of intact structures.

  19. Simultaneous removal of organic matter and salt ions from saline wastewater in bioelectrochemical systems

    KAUST Repository

    Kim, Younggy

    2013-01-01

    A new bioelectrochemical system is proposed for simultaneous removal of salinity and organic matter. In this process, exoelectrogenic microorganisms oxidize organic matter and transfer electrons to the anode, hydrogen is evolved at the cathode by supplying additional voltage, and salt is removed from the wastewater due to the electric potential generated and the use of two ion-exchange membranes. Salinity removal (initial conductivity ~40mS/cm) increased from 21 to 84% by increasing the substrate (sodium acetate) from 2 to 8g/L. A total of 72-94% of the chemical oxygen demand was degraded in the anode and cathode chambers, with 1-4% left in the anode chamber and the balance lost through the anion-exchange membrane into the concentrate waste chamber. The maximum hydrogen production rate was 3.6m3-H2/m3-electrolyte per day at an applied potential of 1.2V. The Coulombic efficiency was ~100%, while the cathode recovery varied from 57 to 100%, depending on the extent of methanogenesis. Exoelectrogenic microbes generated high current densities (7.8mA/cm2) at ≤36g/L of total dissolved solids, but >41g/L eliminated current. These results provide a new method for achieving simultaneous removal of salinity and organic matter from a saline wastewater with H2 production. © 2012 Elsevier B.V.

  20. CO2 Losses from Terrestrial Organic Matter through Photodegradation

    Science.gov (United States)

    Rutledge, S.; Campbell, D. I.; Baldocchi, D. D.; Schipper, L. A.

    2010-12-01

    Net ecosystem exchange (NEE) is the sum of CO2 uptake by plants and CO2 losses from both living plants and dead organic matter. In all but a few ecosystem scale studies on terrestrial carbon cycling, losses of CO2 from dead organic matter are assumed to be the result of microbial respiration alone. Here we provide evidence for an alternative, previously largely underestimated mechanism for ecosystem-scale CO2 emissions. The process of photodegradation, the direct breakdown of organic matter by solar radiation, was found to contribute substantially to the ecosystem scale CO2 losses at both a bare peatland in New Zealand, and a summer-dead grassland in California. Comparisons of daytime eddy covariance (EC) data with data collected at the same time using an opaque chamber and the CO2 soil gradient technique, or with night-time EC data collected during similar moisture and temperature conditions were used to quantify the direct effect of exposure of organic matter to solar radiation. At a daily scale, photodegradation contributed up to 62% and 92% of summer mid-day CO2 fluxes at the de-vegetated peatland and at the grassland during the dry season, respectively. Irradiance-induced CO2 losses were estimated to be 19% of the total annual CO2 loss at the peatland, and almost 60% of the dry season CO2 loss at the grassland. Small-scale measurements using a transparent chamber confirmed that CO2 emissions from air-dried peat and grass occurred within seconds of exposure to light when microbial activity was inhibited. Our findings imply that photodegradation could be important for many ecosystems with exposed soil organic matter, litter and/or standing dead material. Potentially affected ecosystems include sparsely vegetated arid and semi-arid ecosystems (e.g. shrublands, savannahs and other grasslands), bare burnt areas, agricultural sites after harvest or cultivation (especially if crop residues are left on the surface), deciduous forests after leaf fall, or ecosystems

  1. Determination of organic products resulting of chemical and radiochemical decompositions of bitumen. Applications to embedded bitumens

    International Nuclear Information System (INIS)

    Walczak, I.

    2000-01-01

    Bitumen can be used for embedding most of wastes because of its high impermeability and its relatively low reactivity with of chemicals. Bituminization is one of selected solutions in agreement with nuclear safety, waste compatibility and economic criteria. Bitumen, during storage, undergoes an auto-irradiation due to embedded radio-elements. During this stage,drums are not airtight then oxygen is present. In disposal configuration, water, which is a potential vector of radioactivity and organic matter, is an other hazard factor liable to deteriorate the containment characteristics of bitumen wastes. The generation of water-soluble organic complexing agents can affect the integrity of the wasteform due to an increase of the radionuclides solubility. The first aim of this work is the quantitative and qualitative characterisation of soluble organic matter in bitumen leachates. Different leaching solutions were tested (various pH, ionic strength, ratio S/V). When the pH of the leaching solutions increases, the total organic carbon released increases as well. Identified molecules are aromatics like naphthalene, oxidised compounds like alcohols, linear carbonyls, aromatics, glycols and nitrogen compounds. For the cement equilibrated solution (pH 13.5), the effect of ionic strength becomes significative and influences the release of soluble organic matter. This soluble organic matter can be bio-degraded if microorganisms can growth. The second aim of this work is to study the effect of radio-oxidative ageing on the bitumen confinement properties. During radio-oxidation, the chemical properties of bitumen are modified. The μ-IRTF analysis shows the formation of hydroxyl compounds and aromatic acids. The formation of these polar groups does not influence in our study the water uptake. However the organic matter release increases significantly with the irradiation dose. (author)

  2. A Prototype Sensor for In Situ Sensing of Fine Particulate Matter and Volatile Organic Compounds.

    Science.gov (United States)

    Ng, Chee-Loon; Kai, Fuu-Ming; Tee, Ming-Hui; Tan, Nicholas; Hemond, Harold F

    2018-01-18

    Air pollution exposure causes seven million deaths per year, according to the World Health Organization. Possessing knowledge of air quality and sources of air pollution is crucial for managing air pollution and providing early warning so that a swift counteractive response can be carried out. An optical prototype sensor (AtmOptic) capable of scattering and absorbance measurements has been developed to target in situ sensing of fine particulate matter (PM2.5) and volatile organic compounds (VOCs). For particulate matter testing, a test chamber was constructed and the emission of PM2.5 from incense burning inside the chamber was measured using the AtmOptic. The weight of PM2.5 particles was collected and measured with a filter to determine their concentration and the sensor signal-to-concentration correlation. The results of the AtmOptic were also compared and found to trend well with the Dylos DC 1100 Pro air quality monitor. The absorbance spectrum of VOCs emitted from various laboratory chemicals and household products as well as a two chemical mixtures were recorded. The quantification was demonstrated, using toluene as an example, by calibrating the AtmOptic with compressed gas standards containing VOCs at different concentrations. The results demonstrated the sensor capabilities in measuring PM2.5 and volatile organic compounds.

  3. A Prototype Sensor for In Situ Sensing of Fine Particulate Matter and Volatile Organic Compounds

    Directory of Open Access Journals (Sweden)

    Chee-Loon Ng

    2018-01-01

    Full Text Available Air pollution exposure causes seven million deaths per year, according to the World Health Organization. Possessing knowledge of air quality and sources of air pollution is crucial for managing air pollution and providing early warning so that a swift counteractive response can be carried out. An optical prototype sensor (AtmOptic capable of scattering and absorbance measurements has been developed to target in situ sensing of fine particulate matter (PM2.5 and volatile organic compounds (VOCs. For particulate matter testing, a test chamber was constructed and the emission of PM2.5 from incense burning inside the chamber was measured using the AtmOptic. The weight of PM2.5 particles was collected and measured with a filter to determine their concentration and the sensor signal-to-concentration correlation. The results of the AtmOptic were also compared and found to trend well with the Dylos DC 1100 Pro air quality monitor. The absorbance spectrum of VOCs emitted from various laboratory chemicals and household products as well as a two chemical mixtures were recorded. The quantification was demonstrated, using toluene as an example, by calibrating the AtmOptic with compressed gas standards containing VOCs at different concentrations. The results demonstrated the sensor capabilities in measuring PM2.5 and volatile organic compounds.

  4. Source and composition of surface water dissolved organic matter (DOM) and the effect of flood events on the organic matter cycling

    Science.gov (United States)

    Bondar-Kunze, Elisabeth; Welti, Nina; Tritthart, Michael; Baker, Andrew; Pinay, Gilles; Hein, Thomas

    2014-05-01

    Floodplains are often simultaneously affected by land use change, river regulation and loss of hydrological dynamics which alter the surface water connectivity between floodplain and river main channel. These alterations can have significant impacts on the sources of organic matter and their degradation and thus, the carbon cycling of riverine landscapes. Although floodplains are known to be important sources of dissolved organic matter (DOM) within watersheds, reduced hydrological connectivity impair their role. The key questions of our research were to determine i) to what extent the degree of connection between the Danube River and its floodplain controlled the DOM composition with its backwater systems, and ii) what were the effects of the DOM changes on carbon cycling in floodplains during two flood events with different magnitude? In this study we report on the variations in DOM spectrophotometric properties of surface waters in different connected floodplain areas and during two flood events of different magnitude in a section of the Alluvial Zone National Park of the Danube River downstream Vienna, Austria. Two backwater floodplain systems were studied, one backwater system mostly disconnected from the fluvial dynamics except during high flood events (Lower Lobau) and the second one, recently restored and connected even during mean flow conditions (Orth). Fluorescence excitation-emission matrix (EEM) spectrophotometry and water chemical analyses were applied to investigate the DOM dynamics. In both backwater systems 15 sites were sampled monthly for two years and every second day during a flood event.

  5. Linking groundwater dissolved organic matter to sedimentary organic matter from a fluvio-lacustrine aquifer at Jianghan Plain, China by EEM-PARAFAC and hydrochemical analyses.

    Science.gov (United States)

    Huang, Shuang-bing; Wang, Yan-xin; Ma, Teng; Tong, Lei; Wang, Yan-yan; Liu, Chang-rong; Zhao, Long

    2015-10-01

    The sources of dissolved organic matter (DOM) in groundwater are important to groundwater chemistry and quality. This study examined similarities in the nature of DOM and investigated the link between groundwater DOM (GDOM) and sedimentary organic matter (SOM) from a lacustrine-alluvial aquifer at Jianghan Plain. Sediment, groundwater and surface water samples were employed for SOM extraction, optical and/or chemical characterization, and subsequent fluorescence excitation-emission matrix (EEM) and parallel factor analyses (PARAFAC). Spectroscopic properties of bulk DOM pools showed that indices indicative of GDOM (e.g., biological source properties, humification level, aromaticity and molecule mobility) varied within the ranges of those of two extracted end-members of SOM: humic-like materials and microbe-associated materials. The coexistence of PARAFAC compositions and the sustaining internal relationship between GDOM and extracted SOM indicate a similar source. The results from principal component analyses with selected spectroscopic indices showed that GDOM exhibited a transition trend regarding its nature: from refractory high-humification DOM to intermediate humification DOM and then to microbe-associated DOM, with decreasing molecular weight. Correlations of spectroscopic indices with physicochemical parameters of the groundwater suggested that GDOM was released from SOM and was modified by microbial diagenetic processes. The current study demonstrated the associations of GDOM with SOM from a spectroscopic viewpoint and provided new evidence supporting SOM as the source of GDOM. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Impact of organic-mineral matter interactions on thermal reaction pathways for coal model compounds

    Energy Technology Data Exchange (ETDEWEB)

    Buchanan, A.C. III; Britt, P.F.; Struss, J.A. [Oak Ridge National Lab., TN (United States). Chemical and Analytical Sciences Div.

    1995-07-01

    Coal is a complex, heterogeneous solid that includes interdispersed mineral matter. However, knowledge of organic-mineral matter interactions is embryonic, and the impact of these interactions on coal pyrolysis and liquefaction is incomplete. Clay minerals, for example, are known to be effective catalysts for organic reactions. Furthermore, clays such as montmorillonite have been proposed to be key catalysts in the thermal alteration of lignin into vitrinite during the coalification process. Recent studies by Hatcher and coworkers on the evolution of coalified woods using microscopy and NMR have led them to propose selective, acid-catalyzed, solid state reaction chemistry to account for retained structural integrity in the wood. However, the chemical feasibility of such reactions in relevant solids is difficult to demonstrate. The authors have begun a model compound study to gain a better molecular level understanding of the effects in the solid state of organic-mineral matter interactions relevant to both coal formation and processing. To satisfy the need for model compounds that remain nonvolatile solids at temperatures ranging to 450 C, model compounds are employed that are chemically bound to the surface of a fumed silica (Si-O-C{sub aryl}linkage). The organic structures currently under investigation are phenethyl phenyl ether (C{sub 6}H{sub 5}CH{sub 2}CH{sub 2}OC{sub 6}H{sub 5}) derivatives, which serve as models for {beta}-alkyl aryl ether units that are present in lignin and lignitic coals. The solid-state chemistry of these materials at 200--450 C in the presence of interdispersed acid catalysts such as small particle size silica-aluminas and montmorillonite clay will be reported. Initial focus will be on defining the potential impact of these interactions on coal pyrolysis and liquefaction.

  7. Understanding dissolved organic matter reactivity in a global context: tribute to Dr. George Aiken's many contributions

    Science.gov (United States)

    McKnight, Diane

    2017-04-01

    As Dr. George Aiken emphasized throughout his distinguished research career, the diversity of sources of dissolved organic material (DOM) is associated with a diversity of dissolved organic compounds with a range of chemistries and reactivities that are present in the natural environment. From a limnological perspective, dissolved organic matter (DOM) can originate from allochthonous sources on the landscape which drains into a lake, river, wetland, coastal region, or other aquatic ecosystem, or from autochthonous sources within the given aquatic ecosystem. In many landscapes, the precursor organic materials that contribute to the DOM of the associated aquatic ecosystem can be derived from diverse sources, e.g. terrestrial plants, plant litter, organic material in different soil horizons, and the products of microbial growth and decay. Yet, through his focus on the underlying chemical processes a clear, chemically robust foundation for understanding DOM reactivity has emerged from Aiken's research. These processes include the enhancement in solubility due to ionized carboxylic acid functional groups and the reactions of organic sulfur groups with mercury. This approach has advanced understand of carbon cycling in the lakes of the Mars-like barren landscapes of the McMurdo Dry Valleys in Antarctica and the rivers draining the warming tundra of the Arctic.

  8. 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.

  9. Sorption of organic chemicals at biogeochemical interfaces - calorimetric measurements

    Science.gov (United States)

    Krüger, J.; Lang, F.; Siemens, J.; Kaupenjohann, M.

    2009-04-01

    Biogeochemical interfaces in soil act as sorbents for organic chemicals, thereby controlling the degradation and mobility of these substances in terrestrial environments. Physicochemical properties of the organic chemicals and the sorbent determine sorptive interactions. We hypothesize that the sorption of hydrophobic organic chemicals ("R-determined" chemicals) is an entropy-driven partitioning process between the bulk aqueous phase and biogeochemical interface and that the attachment of more polar organic chemicals ("F-determined" chemicals) to mineral surfaces is due to electrostatic interactions and ligand exchange involving functional groups. In order to determine thermodynamic parameters of sorbate/sorbent interactions calorimetric titration experiments have been conducted at 20˚ C using a Nanocalorimeter (TAM III, Thermometric). Solutions of different organic substances ("R-determined" chemicals: phenanthrene, bisphenol A, "F-determined" chemicals: MCPA, bentazone) with concentrations of 100 mol l-1 were added to suspensions of pure minerals (goethite, muscovite, and kaolinite and to polygalacturonic acid (PGA) as model substance for biofilms in soil. Specific surface, porosity, N and C content, particle size and point of zero charge of the mineral were analyzed to characterize the sorbents. The obtained heat quantities for the initial injection of the organic chemicals to the goethite were 55 and 71 J for bisphenol A and phenanthrene ("R-determined representatives") and 92 and 105 J for MCPA and bentazone ("F-determined" representatives). Further experiments with muscovite, kaolinite and PGA are in progress to determine G and H of the adsorption process.

  10. Limitations in Using Chemical Oxidative Potential to Understand Oxidative Stress from Particulate Matter

    Science.gov (United States)

    Chan, A. W. H.; Wang, S.; Wang, X.; Kohl, L.; Chow, C. W.

    2017-12-01

    Particulate matter (PM) in the atmosphere is known to cause adverse cardiorespiratory health effects. It has been suggested that the ability of PM to generate oxidative stress leads to a proinflammatory response. In this work, we study the biological relevance of using a chemical oxidative potential (OP) assay to evaluate proinflammatory response in airway epithelial cells. Here we study the OPs of laboratory secondary organic aerosol (SOA) and metal mixtures, ambient PM from India, ash from the 2016 Alberta wildfires, and diesel exhaust particles. We use SOA derived from naphthalene and from monoterpenes as model systems for SOA. We measure OP using the dithiothreitol (DTT) assay, and cytosolic reactive oxygen species (ROS) production in BEAS-2B cell culture was measured using CellROX assay. We found that both SOA and copper show high OPs individually, but the OP of the combined SOA/copper mixture, which is more atmospherically relevant, was lower than either of the individual OPs. The reduced activity is attributed to chelation between metals and organic compounds using proton nuclear magnetic resonance. There is reasonable association between DTT activity and cellular ROS production within each particle type, but weak association across different particle types, suggesting that particle composition plays an important role in distinguishing between antioxidant consumption and ROS production. Our results highlight that while oxidative potential is a useful metric of PM's ability to generate oxidative stress, the chemical composition and cellular environment should be considered in understanding health impacts of PM.

  11. Iron traps terrestrially derived dissolved organic matter at redox interfaces

    Science.gov (United States)

    Riedel, Thomas; Zak, Dominik; Biester, Harald; Dittmar, Thorsten

    2013-01-01

    Reactive iron and organic carbon are intimately associated in soils and sediments. However, to date, the organic compounds involved are uncharacterized on the molecular level. At redox interfaces in peatlands, where the biogeochemical cycles of iron and dissolved organic matter (DOM) are coupled, this issue can readily be studied. We found that precipitation of iron hydroxides at the oxic surface layer of two rewetted fens removed a large fraction of DOM via coagulation. On aeration of anoxic fen pore waters, >90% of dissolved iron and 27 ± 7% (mean ± SD) of dissolved organic carbon were rapidly (within 24 h) removed. Using ultra-high-resolution MS, we show that vascular plant-derived aromatic and pyrogenic compounds were preferentially retained, whereas the majority of carboxyl-rich aliphatic acids remained in solution. We propose that redox interfaces, which are ubiquitous in marine and terrestrial settings, are selective yet intermediate barriers that limit the flux of land-derived DOM to oceanic waters. PMID:23733946

  12. Hydrogen and carbon isotopes of petroleum and related organic matter

    International Nuclear Information System (INIS)

    Yeh, H.W.; Epstein, S.

    1981-01-01

    D/H and 13 C/ 12 C ratios were measured for 114 petroleum samples and for several samples of related organic matter. DeltaD of crude oil ranges from -85 to -181 per thousand except for one distillate (-250 per thousand) from the Kenai gas field; delta 13 C of crude oil ranges from -23.3 to -32.5 per thousand. Variation in deltaD and delta 13 C values of compound-grouped fractions of a crude oil is small, 3 and 1.1 per thousand, respectively, and the difference in deltaD and delta 13 C between oil and coeval wax is slight. Gas fractions are 53 to 70 and 22.6 to 23.2 per thousand depleted in D and 13 C, respectively, relative to the coexisting oil fractions. The deltaD and delta 13 C values of the crude oils appear to be largely determined by the isotopic compositions of their organic precursors. The contribution of terrestrial organic debris to the organic precursors of most marine crude oils may be significant. (author)

  13. Humification and nonhumification pathways of the organic matter stabilization in soil: A review

    Science.gov (United States)

    Semenov, V. M.; Tulina, A. S.; Semenova, N. A.; Ivannikova, L. A.

    2013-04-01

    Polymeric and supramolecular models of humic substances (HSs) are considered. It has been noted that the HSs in natural objects can simultaneously occur in the forms of macromolecular polymers and supramolecularly organized monomers; macromolecular polymers of HSs can have some properties of suprastructures or be associated into aggregates, and covalent bonds can be formed between the monomers of supramolecules. Mineral particles of soil act as catalysts in chemical reactions between individual compounds, sorbents of biomolecules, and a surface for self-assembling HSs. It is supposed that the combination of such physicochemical processes and phenomena in soil as cementation, charring, incrustation, occlusion, sedimentation, sorption, coagulation, flocculation, encapsulation, complexation, and intercalation, as well as the entrapment of macroorganic, particulate, and soluble organic substances in micropores, can be as important for the stabilization of organic matter as the interactions between biomolecules with the formation of HSs.

  14. Chromophoric Dissolved Organic Matter in Southwestern Greenland Lakes

    Science.gov (United States)

    Osburn, C. L.; Giles, M. E.; Underwood, G. J. C.

    2014-12-01

    Dissolved organic matter (DOM) is an important property of Arctic lake ecosystems, originating from allochthonous inputs from catchments and autochthonous production by plankton in the water column. Little is known about the quality of DOM in Arctic lakes that lack substantial inputs from catchments and such lakes are abundant in southwestern Greenland. Colored dissolved organic matter (CDOM), the fraction that absorbs ultraviolet (UV) and visible light, is the controlling factor for the optical properties of many surface waters and as well informs on the quality of DOM. We examined the quality of CDOM in 21 lakes in southwestern Greenland, from the ice sheet to the coast, as part of a larger study examining the role of DOM in regulating microbial communities in these lakes. DOM was size fractioned and absorbance and fluorescence was measured on each size fraction, as well as on bulk DOM. The specific ultraviolet absorbance (SUVA) at 254 nm (SUVA254), computed by normalizing absorption (a254) to dissolved organic carbon (DOC) concentration, provided an estimate of the aromatic carbon content of DOM. SUVA values were generally CDOM fluorescence was used to determine the relative abundance of allochthonous and autochthonous DOM in all size fractions. Younger lakes near the ice sheet and lakes near the coast had lower amounts of CDOM and appeared more microbial in quality. However, lakes centrally located between the ice sheet and the coast had the highest CDOM concentrations and exhibited strong humic fluorescence. Overall distinct differences in CDOM quality were observed between lake locations and among DOM size fractions.

  15. Organic matter loss from cultivated peat soils in Sweden

    Science.gov (United States)

    Berglund, Örjan; Berglund, Kerstin

    2015-04-01

    The degradation of drained peat soils in agricultural use is an underestimated source of loss of organic matter. Oxidation (biological degradation) of agricultural peat soils causes a loss of organic matter (OM) of 11 - 22 t ha-1 y-1 causing a CO2 emission of 20 - 40 t ha-1 y-1. Together with the associated N2O emissions from mineralized N this totals in the EU to about 98.5 Mton CO2 eq per year. Peat soils are very prone to climate change and it is expected that at the end of this century these values are doubled. The degradation products pollute surface waters. Wind erosion of peat soils in arable agriculture can cause losses of 3 - 30 t ha-1 y-1 peat also causing air pollution (fine organic particles). Subsidence rates are 1 - 2 cm per year which leads to deteriorating drainage effect and make peat soils below sea or inland water levels prone to flooding. Flooding agricultural peat soils is in many cases not possible without high costs, high GHG emissions and severe water pollution. Moreover sometimes cultural and historic landscapes are lost and meadow birds areas are lost. In areas where the possibility to regulate the water table is limited the mitigation options are either to increase biomass production that can be used as bioenergy to substitute some fossil fuel, try to slow down the break-down of the peat by different amendments that inhibit microbial activity, or permanent flooding. The negative effects of wind erosion can be mitigated by reducing wind speed or different ways to protect the soil by crops or fiber sheets. In a newly started project in Sweden a typical peat soil with and without amendment of foundry sand is cropped with reed canary grass, tall fescue and timothy to investigate the yield and greenhouse gas emissions from the different crops and how the sand effect the trafficability and GHG emissions.

  16. Photochemical Reactivity of Dissolved Organic Matter in Boreal Lakes

    Science.gov (United States)

    Gu, Y.; Vuorio, K.; Tiirola, M.; Perämäki, S.; Vahatalo, A.

    2016-12-01

    Boreal lakes are rich in dissolved organic matter (DOM) that terrestrially derived from forest soil and wetland, yet little is known about potential for photochemical transformation of aquatic DOM in boreal lakes. Transformation of chromophoric dissolved organic matter (CDOM) can decrease water color and enhance microbial mineralization, affecting primary production and respiration, which both affect the CO2 balance of the lakes. We used laboratory solar radiation exposure experiments with lake water samples collected from 54 lakes located in Finland and Sweden, representing different catchment composition and watershed location to assess photochemical reactivity of DOM. The pH of water samples ranged from 5.4 to 8.3, and the concentrations of dissolved iron (Fe) were between samples received simulated solar radiation corresponding to a daily dose of sunlight, and photomineralization of dissolved organic carbon (DOC) to dissolved inorganic carbon (DIC) was measured for determination of spectral apparent quantum yields (AQY). During irradiation, photobleaching decreased the absorption coefficients of CDOM at 330 nm between 4.9 and 79 m-1 by 0.5 to 11 m-1. Irradiation generated DIC from 2.8 to 79 μmol C L-1. The AQY at 330 nm ranged between 31 and 273 ×10-6 mol C mol photons-1 h-1, which was correlated positively with concentration of dissolved Fe, and negatively with pH. Further statistical analyze indicated that the interaction between pH and Fe may explain much of the photochemical reactivity of DOM in the examined lakes, and land cover concerns main catchment areas also can have impact on the photoreaction process. This study may suggest how environmental conditions regulate DOM photomineralization in boreal lakes.

  17. Quality of fresh organic matter affects priming of soil organic matter and substrate utilization patterns of microbes

    Science.gov (United States)

    Wang, Hui; Boutton, Thomas W.; Xu, Wenhua; Hu, Guoqing; Jiang, Ping; Bai, Edith

    2015-05-01

    Changes in biogeochemical cycles and the climate system due to human activities are expected to change the quantity and quality of plant litter inputs to soils. How changing quality of fresh organic matter (FOM) might influence the priming effect (PE) on soil organic matter (SOM) mineralization is still under debate. Here we determined the PE induced by two 13C-labeled FOMs with contrasting nutritional quality (leaf vs. stalk of Zea mays L.). Soils from two different forest types yielded consistent results: soils amended with leaf tissue switched faster from negative PE to positive PE due to greater microbial growth compared to soils amended with stalks. However, after 16 d of incubation, soils amended with stalks had a higher PE than those amended with leaf. Phospholipid fatty acid (PLFA) results suggested that microbial demand for carbon and other nutrients was one of the major determinants of the PE observed. Therefore, consideration of both microbial demands for nutrients and FOM supply simultaneously is essential to understand the underlying mechanisms of PE. Our study provided evidence that changes in FOM quality could affect microbial utilization of substrate and PE on SOM mineralization, which may exacerbate global warming problems under future climate change.

  18. Exploring the Contribution of Primary Marine Organic Matter to the Arctic Boundary Layer

    Science.gov (United States)

    Collins, D. B.; Chang, R. Y. W.; Boyer, M.; Abbatt, J.

    2016-12-01

    The ocean is a significant source of aerosol to the atmosphere, and contributes significantly to the aerosol population especially in remote locations. Both primary and secondary processes connect the ocean to ambient aerosol loadings, but the extent to which the ocean is a source of organic material to the atmosphere is a current topic of scientific debate. The contribution of primary marine aerosol to atmospheric organic matter may have an influence on the water uptake properties and chemical reactivity of primary marine aerosol particles, influencing their climate-relevant properties. In this study, we characterize the contribution of primary marine aerosol to the arctic marine boundary layer using coincident quantitative measurements of freshly-produced sea spray aerosol and ambient marine aerosol to the arctic boundary layer during an expedition aboard the CCGS Amundsen. Sea spray production experiments were conducted during the cruise using a tank fitted with a plunging waterfall apparatus, a technique which has been recently shown to closely mimic the aerosol production behavior of controlled breaking waves. Comparison of the chemical composition of sea spray particles generated from water samples in various locations throughout the Canadian Archipelago will be presented. A tracer analysis of specific compounds known to be important contributors to primary marine organic material are tracked using GC/MS, along with those known to be tracers of biological aerosol and other organic matter sources. Size-segregated trends in tracer concentrations and ratios with inorganic components will be discussed in the context of understanding the contribution of primary organics to the Arctic atmosphere and in comparison with other sources of organic material observed during the ship-board campaign.

  19. Chemical composition and in vitro dry matter digestibility of Moringa ...

    African Journals Online (AJOL)

    The effect of caecal inoculum of rabbit on in vitro gas production and dry matter digestibility of Moringa oleifera, Azadirachta indica and Aspilia africana leaf meals at different levels of 0%, 15% and 30%. Leave samples were analyzed for crude protein (CP), lignin (ADL), acid (ADF) and neutral (NDF) detergent fibres.

  20. Storage and turnover of organic matter in soil

    Energy Technology Data Exchange (ETDEWEB)

    Torn, M.S.; Swanston, C.W.; Castanha, C.; Trumbore, S.E.

    2008-07-15

    Historically, attention on soil organic matter (SOM) has focused on the central role that it plays in ecosystem fertility and soil properties, but in the past two decades the role of soil organic carbon in moderating atmospheric CO{sub 2} concentrations has emerged as a critical research area. This chapter will focus on the storage and turnover of natural organic matter in soil (SOM), in the context of the global carbon cycle. Organic matter in soils is the largest carbon reservoir in rapid exchange with atmospheric CO{sub 2}, and is thus important as a potential source and sink of greenhouse gases over time scales of human concern (Fischlin and Gyalistras 1997). SOM is also an important human resource under active management in agricultural and range lands worldwide. Questions driving present research on the soil C cycle include: Are soils now acting as a net source or sink of carbon to the atmosphere? What role will soils play as a natural modulator or amplifier of climatic warming? How is C stabilized and sequestered, and what are effective management techniques to foster these processes? Answering these questions will require a mechanistic understanding of how and where C is stored in soils. The quantity and composition of organic matter in soil reflect the long-term balance between plant carbon inputs and microbial decomposition, as well as other loss processes such as fire, erosion, and leaching. The processes driving soil carbon storage and turnover are complex and involve influences at molecular to global scales. Moreover, the relative importance of these processes varies according to the temporal and spatial scales being considered; a process that is important at the regional scale may not be critical at the pedon scale. At the regional scale, SOM cycling is influenced by factors such as climate and parent material, which affect plant productivity and soil development. More locally, factors such as plant tissue quality and soil mineralogy affect

  1. 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.

  2. Organic Matter in Extraterrestrial Water-Bearing Salt Crystals

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Kebukwa, Y.; Fries, M.; Steele, A.

    2017-01-01

    Introduction: Direct samples of early Solar System fluids are present in two thermally-metamorphosed ordinary chondrite regolith breccias (Monahans (1998) [H5] and Zag [H3-6]), which were found to contain brine-bearing halite (NaCl) crystals that have been added to the regolith of an S-type asteroid following asteroidal metamorphism [1, 2]. The brine-bearing halite grains were proposed to be formed on an icy C-type asteroids (possibly Ceres), and transferred to an S-type asteroid via cryovolcanic event(s) [3]. A unique aspect of these halites is that they contain abundant organic rich solid inclusions hosted within the halites alongside the water inclusions. Methods: We analyzed in detail the compositions of the organic solids and the amino acid content of the halite crystals with two-step laser desorption/laser ionization mass spectrometry (L(sup 2) MS), Raman spectroscopy, X-ray absorption near edge structure (XANES), nanoscale secondary ion mass spectrometry (NanoSIMS), and ultra-performance liquid chromatography fluorescence detection and quadrupole time of flight hybrid mass spectrometry (UPLC-FD/QToF-MS). Results and Discussion: The L(sup 2) MS results show signatures of low-mass polyaromatic hydro-carbons (PAHs) indicated by sequences of peaks separated by 14 atomic mass units (amu) due to successive addition of methylene (CH2) groups to the PAH skeletons [4]. Raman spectra of the micron-sized solid inclusions of the halites indicate the presence of abundant and highly variable organic matter that include a mixture of short-chain aliphatic compounds and macromolecular carbon. C-XANES analysis identified C-rich areas with peaks at 285.0 eV (aromatic C=C) and 286.6 eV (vinyl-keto C=O). However, there is no 1s-sigma* exciton peak (291.7 eV) that is indicative of the development of graphene structure [5], which suggests the organics were synthesized cold. Na-noSIMS analyses show C-rich and N-rich areas that exhibit similar isotopic values with that of the IOM in

  3. Transformation of organic matters in animal wastes during composting

    International Nuclear Information System (INIS)

    Wang, Ke; He, Chao; You, Shijie; Liu, Weijie; Wang, Wei; Zhang, Ruijun; Qi, Huanhuan; Ren, Nanqi

    2015-01-01

    Highlights: • Transformation of swine, cow and chicken manures during composting was compared. • Evolution of organics was analyzed by element analysis, FTIR, "1"3C NMR and Py/GC/MS. • Microbial utilization capacity on various substrates in the manures was evaluated. • Spatial difference of degradation rate inside the manure particle was investigated. - Abstract: The transformation of organic matters in swine, cow and chicken manures was compared and evaluated using elemental analysis, FTIR, "1"3C NMR, pyrolysis/GC/MS, Biolog and multiple fluorochrome over 60 days composting. The results revealed that cow manure exhibited the greatest C/N and aromaticity, whereas chicken manure exhibited the highest nitrogen and sulfur contents. O-alkyl-C was predominant carbon structure in the three manures. Alkyl-C and carboxyl-C were decomposed dramatically in initial 10 days, and mineralization of O-alkyl-C dominated the curing stage. During pyrolysis of chicken, cow, and swine manures, the majority products were fatty acids, phenols and cholestene derivatives, respectively, however, phenols and cholestene derivatives were strongly reduced in the mature manures. Furthermore, microorganisms in the raw cow, chicken and swine manure demonstrated the highest degradation capabilities for carbohydrates, lipids and amino acids, respectively. Spatial differences in the contents of solid organics in the manure particles were negligible through detection by multiple staining methods during composting.

  4. Sources, Ages, and Alteration of Organic Matter in Estuaries.

    Science.gov (United States)

    Canuel, Elizabeth A; Hardison, Amber K

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

  5. Transformation of organic matters in animal wastes during composting

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ke, E-mail: hitwk@sina.com [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); He, Chao [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141 (Singapore); You, Shijie, E-mail: sjyou@hit.edu.cn [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); Liu, Weijie [School of Life Science, The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, Jiangsu Normal University, Xuzhou 221116, Jiangsu Province (China); Wang, Wei; Zhang, Ruijun [School of Municipal and Environmental Engineering, State Key Laboratory of Urban Water Resource and Environment (SKLUWER), Harbin Institute of Technology, 73 Huanghe road, Harbin, Heilongjiang 150090 (China); Qi, Huanhuan; Ren, Nanqi [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141 (Singapore)

    2015-12-30

    Highlights: • Transformation of swine, cow and chicken manures during composting was compared. • Evolution of organics was analyzed by element analysis, FTIR, {sup 13}C NMR and Py/GC/MS. • Microbial utilization capacity on various substrates in the manures was evaluated. • Spatial difference of degradation rate inside the manure particle was investigated. - Abstract: The transformation of organic matters in swine, cow and chicken manures was compared and evaluated using elemental analysis, FTIR, {sup 13}C NMR, pyrolysis/GC/MS, Biolog and multiple fluorochrome over 60 days composting. The results revealed that cow manure exhibited the greatest C/N and aromaticity, whereas chicken manure exhibited the highest nitrogen and sulfur contents. O-alkyl-C was predominant carbon structure in the three manures. Alkyl-C and carboxyl-C were decomposed dramatically in initial 10 days, and mineralization of O-alkyl-C dominated the curing stage. During pyrolysis of chicken, cow, and swine manures, the majority products were fatty acids, phenols and cholestene derivatives, respectively, however, phenols and cholestene derivatives were strongly reduced in the mature manures. Furthermore, microorganisms in the raw cow, chicken and swine manure demonstrated the highest degradation capabilities for carbohydrates, lipids and amino acids, respectively. Spatial differences in the contents of solid organics in the manure particles were negligible through detection by multiple staining methods during composting.

  6. Acid-base properties of Baltic Sea dissolved organic matter

    Science.gov (United States)

    Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

    2017-09-01

    Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

  7. [Evolution of Dissolved Organic Matter Properties in a Constructed Wetland of Xiao River, Hebei].

    Science.gov (United States)

    Ma, Li-na; Zhang, Hui; Tan, Wen-bing; Yu, Min-da; Huang, Zhi-gang; Gao, Ru-tai; Xi, Bei-dou; He, Xiao-song

    2016-01-01

    The evolution of water DOC and COD, and the source, chemical structure, humification degree and redox of dissolved organic matter (DOM) in a constructed wetland of Xiao River, Hebei, was investigated by 3D excitation--emission matrix fluorescence spectroscopy coupled with ultraviolet spectroscopy and chemical reduction, in order to explore the geochemical processes and environmental effects of DOM. Although DOC contributes at least 60% to COD, its decrease in the constructed wetland is mainly caused by the more extensive degradation of elements N, H, S, and P than C in DOM, and 65% is contributed from the former. DOM is mainly consisted of microbial products based on proxies f470/520 and BIX, indicating that DOM in water is apparently affected by microbial degradation. The result based on PARAFAC model shows that DOM in the constructed wetland contains protein-like and humus-like components, and Fulvic- and humic-like components are relatively easier to degrade than protein-like components. Fulvic- and humic-like components undergo similar decomposition in the constructed wetland. A common source of chromophoric dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM) exists; both CDOM and FDOM are mainly composed of a humus-like material and do not exhibit selective degradation in the constructed wetland. The proxies E2 /E3, A240-400, r(A, C) and HIX in water have no changes after flowing into the constructed wetland, implying that the humification degree of DOM in water is hardly affected by wet constructed wetland. However, the constructed wetland environment is not only beneficial in forming the reduced state of DOM, but also facilitates the reduction of ferric. It can also improve the capability of DOM to function as an electron shuttle. This result may be related to the condition that the aromatic carbon of DOM can be stabilized well in the constructed wetland.

  8. New monoaromatic steroids in organic matter of the apocatagenesis zone

    Science.gov (United States)

    Kashirtsev, V. A.; Fomin, A. N.; Shevchenko, N. P.; Dolzhenko, K. V.

    2016-08-01

    According to the materials of geochemical study in the core of the ultradeep hole SV-27 of aromatic fractions of bitumoids of the Vilyui syneclise (East Siberia) by the method of chromatography-mass spectrometry, starting from the depth of >5000 m, four diastereomers of previously unknown hydrocarbons, which become predominant in the fraction at a depth of ˜6500 m, were distinguished. Similar hydrocarbons were found in organic matter of Upper Paleozoic rocks of the Kharaulakh anticlinorium in the Verkhoyansk folded area. According to the intense molecular ion m/z 366 and the character of the basic fragmental ions (m/z 238, 309, and 323), the major structure of the compounds studied was determined as 17-desmethyl-23-methylmonoaromatic steroid C27. The absence of such steroids in oil of the Vilyui syneclise shows that deep micro-oils did not participate in the formation of oil fringes of gas condensate deposits of the region.

  9. Leachate pretreatment for enhancing organic matter conversion in landfill bioreactor

    International Nuclear Information System (INIS)

    He Pinjing; Qu Xian; Shao Liming; Li Guojian; Lee Duujong

    2007-01-01

    Direct recycling of leachate from refuse of high food waste content was shown to ineffectively stabilize the refuse. This work aims at evaluating the effects of three pretreatments of leachate on the refuse stabilization efficiency were investigated. Pretreatment of leachate using an anaerobic upflow filtration bioreactor (UFB) or a well-decomposed waste layer could reduce the COD and provide methanogens, both were beneficial to establish early methanogenesis status. Using an aerobic sequential batch reactor (SBR) to pretreat the leachate could reduce its COD to 1000 mg l -1 , but the fully developed methanogenesis phase would be built up in a later stage. The organic matters in the effluent leachate inhibited both the hydrolysis/acidogenesis and the methanogenesis steps in the refuse. With the dilution and acid neutralization effects by the recycled leachate, a favorable methanogenetic environment could be produced from the column's top, which moved downward along, and finally made the breakthrough of the column

  10. Effect of organic matter on 125I diffusion in bentonite

    International Nuclear Information System (INIS)

    Tao Wu; Qing Zheng

    2015-01-01

    Through-diffusion method was conducted to investigate the diffusion behavior of 125 I in bentonite in present of organic matter, such as polyaminopolycarboxylate EDTA, oxalic acid, hydrazine and humic acid HA. The effective diffusion coefficient D e value and rock capacity factor α were (2.32.6) × 10 -11 m 2 /s and 0.040-0.052, respectively. The small difference showed that iodine was preferentially associated with silicoaluminate mineral as an inorganic form. In present of HA, the D a value of 125 I was almost two orders of magnitude higher than that of HA and humic substances HS. The D e and α derived from the experiments were used to simulate its diffusion in the designed bentonite obstacle of high-level radioactive waste repository and the results showed that 125 I can be transported from 30 to 50 cm thickness of bentonite to the far-field of repository in several years. (author)

  11. Inner filter correction of dissolved organic matter fluorescence

    DEFF Research Database (Denmark)

    Kothawala, D.N.,; Murphy, K.R.; Stedmon, Colin

    2013-01-01

    The fluorescence of dissolved organic matter (DOM) is suppressed by a phenomenon of self-quenching known as the inner filter effect (IFE). Despite widespread use of fluorescence to characterize DOM in surface waters, the advantages and constraints of IFE correction are poorly defined. We assessed...... the effectiveness of a commonly used absorbance-based approach (ABA), and a recently proposed controlled dilution approach (CDA) to correct for IFE. Linearity between corrected fluorescence and total absorbance (ATotal; the sum of absorbance at excitation and emission wavelengths) across the full excitation......-emission matrix (EEM) in dilution series of four samples indicated both ABA and CDA were effective to an absorbance of at least 1.5 in a 1 cm cell, regardless of wavelength positioning. In regions of the EEMs where signal to background noise (S/N) was low, CDA correction resulted in more variability than ABA...

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

    DEFF Research Database (Denmark)

    Petersen, Søren O; Sommer, Sven G.

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

  13. Dynamics of chemical equilibrium of hadronic matter close to Tc

    International Nuclear Information System (INIS)

    Noronha-Hostler, J.; Beitel, M.; Greiner, C.; Shovkovy, I.

    2010-01-01

    Quick chemical equilibration times of hadrons (specifically, pp-bar, KK-bar, ΛΛ-bar, and ΩΩ-bar pairs) within a hadron gas are explained dynamically using Hagedorn states, which drive particles into equilibrium close to the critical temperature. Within this scheme, we use master equations and derive various analytical estimates for the chemical equilibration times. We compare our model to recent lattice results and find that for both T c =176 MeV and T c =196 MeV, the hadrons can reach chemical equilibrium almost immediately, well before the chemical freeze-out temperatures found in thermal fits for a hadron gas without Hagedorn states. Furthermore, the ratios p/π, K/π, Λ/π, and Ω/π match experimental values well in our dynamical scenario.

  14. Molecular characterization of dissolved organic matter (DOM): a critical review.

    Science.gov (United States)

    Nebbioso, Antonio; Piccolo, Alessandro

    2013-01-01

    Advances in water chemistry in the last decade have improved our knowledge about the genesis, composition, and structure of dissolved organic matter, and its effect on the environment. Improvements in analytical technology, for example Fourier-transform ion cyclotron (FT-ICR) mass spectrometry (MS), homo and hetero-correlated multidimensional nuclear magnetic resonance (NMR) spectroscopy, and excitation emission matrix fluorimetry (EEMF) with parallel factor (PARAFAC) analysis for UV-fluorescence spectroscopy have resulted in these advances. Improved purification methods, for example ultrafiltration and reverse osmosis, have enabled facile desalting and concentration of freshly collected DOM samples, thereby complementing the analytical process. Although its molecular weight (MW) remains undefined, DOM is described as a complex mixture of low-MW substances and larger-MW biomolecules, for example proteins, polysaccharides, and exocellular macromolecules. There is a general consensus that marine DOM originates from terrestrial and marine sources. A combination of diagenetic and microbial processes contributes to its origin, resulting in refractory organic matter which acts as carbon sink in the ocean. Ocean DOM is derived partially from humified products of plants decay dissolved in fresh water and transported to the ocean, and partially from proteinaceous and polysaccharide material from phytoplankton metabolism, which undergoes in-situ microbial processes, becoming refractory. Some of the DOM interacts with radiation and is, therefore, defined as chromophoric DOM (CDOM). CDOM is classified as terrestrial, marine, anthropogenic, or mixed, depending on its origin. Terrestrial CDOM reaches the oceans via estuaries, whereas autochthonous CDOM is formed in sea water by microbial activity; anthropogenic CDOM is a result of human activity. CDOM also affects the quality of water, by shielding it from solar radiation, and constitutes a carbon sink pool. Evidence in support

  15. Biochar effect on the mineralization of soil organic matter

    Directory of Open Access Journals (Sweden)

    Sander Bruun

    2012-05-01

    Full Text Available The objective of this work was to verify whether the addition of biochar to the soil affects the degradation of litter and of soil organic matter (SOM. In order to investigate the effect of biochar on the mineralization of barley straw, soil was incubated with 14C-labelled barley straw with or without unlabelled biochar. To investigate the effect of straw on the mineralization of biochar, soil was incubated with 14C-labelled biochar with or without straw. In addition, to investigate the effect of biochar on old SOM, a soil labelled by applying labelled straw 40 years ago was incubated with different levels of biochar. All experiments had a control treatment, without any soil amendment. The effect of biochar on the straw mineralization was small and nonsignificant. Without biochar, 48±0.2% of the straw carbon was mineralized within the 451 days of the experiment. In comparison, 45±1.6% of C was mineralized after biochar addition of 1.5 g kg-1. In the SOM-labelled soil, the organic matter mineralized more slowly with the increasing doses of biochar. Biochar addition at 7.7 g kg-1 reduced SOM mineralization from 6.6 to 6.3%, during the experimental period. The addition of 15.5 g kg-1 of biochar reduced the mineralized SOM to 5.7%. There is no evidence of increased degradation of either litter or SOM due to biochar addition; consequently, there is no evidence of decreased stability of SOM.

  16. Effect of organic matter amendment, arsenic amendment and water management regime on rice grain arsenic species

    International Nuclear Information System (INIS)

    Norton, Gareth J.; Adomako, Eureka E.; Deacon, Claire M.; Carey, Anne-Marie; Price, Adam H.; Meharg, Andrew A.

    2013-01-01

    Arsenic accumulation in rice grain has been identified as a major problem in some regions of Asia. A study was conducted to investigate the effect of increased organic matter in the soil on the release of arsenic into soil pore water and accumulation of arsenic species within rice grain. It was observed that high concentrations of soil arsenic and organic matter caused a reduction in plant growth and delayed flowering time. Total grain arsenic accumulation was higher in the plants grown in high soil arsenic in combination with high organic matter, with an increase in the percentage of organic arsenic species observed. The results indicate that the application of organic matter should be done with caution in paddy soils which have high soil arsenic, as this may lead to an increase in accumulation of arsenic within rice grains. Results also confirm that flooding conditions substantially increase grain arsenic. -- Highlights: ► High soil arsenic and organic matter caused a reduction in plant growth. ► A delayed flowering time was observed in high arsenic and organic matter soil. ► Total grain arsenic increased in high arsenic and organic matter soil. ► Percentage organic arsenic in the grain altered in arsenic and organic matter soil. -- The addition of high amounts of organic matter to soils led to an increase in total rice grain arsenic, as well as alteration in the percentage arsenic species in the rice grains

  17. Effects of organic matter and ageing on the bioaccessibility of arsenic

    International Nuclear Information System (INIS)

    Meunier, Louise; Koch, Iris; Reimer, Kenneth J.

    2011-01-01

    Arsenic-contaminated soils may pose a risk to human health. Redevelopment of contaminated sites may involve amending soils with organic matter, which potentially increases arsenic bioaccessibility. The effects of ageing on arsenic-contaminated soils mixed with peat moss were evaluated in a simulated ageing period representing two years, during which arsenic bioaccessibility was periodically measured. Significant increases (p = 0.032) in bioaccessibility were observed for 15 of 31 samples tested, particularly in comparison with samples originally containing >30% bioaccessible arsenic in soils naturally rich in organic matter (>25%). Samples where percent arsenic bioaccessibility was unchanged with age were generally poor in organic matter (average 7.7%) and contained both arsenopyrite and pentavalent arsenic forms that remained unaffected by the organic matter amendments. Results suggest that the addition of organic matter may lead to increases in arsenic bioaccessibility, which warrants caution in the evaluation of risks associated with redevelopment of arsenic-contaminated land. - Highlights: → Adding organic matter to contaminated soils may increase arsenic bioaccessibility. → Ageing soils with >25% organic matter can lead to increased arsenic bioaccessibility. → No changes in arsenic bioaccessibility for soils poor in organic matter (mean 7.7%). → No changes in arsenic bioaccessibility for samples containing arsenopyrite. → Organic matter in soil may favour oxidation of trivalent arsenic to pentavalent form. - Adding organic carbon may increase arsenic bioaccessibility, especially in samples originally containing >30% bioaccessible arsenic in organic carbon-rich soils (>25%).

  18. The chemical composition and in vitro dry matter digestibility of ...

    African Journals Online (AJOL)

    The mean IVDMD of maize residues obtained by means of a whole plant maize harvester was found to be relatively high (IVDMD = 55.6±7.0%) while the crude protein (CP) (46±10 g/kg dry matter (DM)) and phosphorus (P) (1.2±0.5 g/kg DM) concentrations were below the maintenance requirement for dry gestating beef ...

  19. ORGANIC MATTER AND CRUDE PROTEIN DEGRADATION SYNCHRONY IN DIETS SELECTED BY RANGE GOATS.

    Directory of Open Access Journals (Sweden)

    Rafael Ramírez Orduña

    2010-09-01

    Full Text Available The study was carried out with the aim to asses the synchrony of organic matter and crude protein degradation in the rumen of diets selected by range goats through two years. Five esophageal cannulated adult male goats were used to collect extrusa samples during summer (August 9–13 and autumn (November 29 –December 3 of 2006, winter (February 20 – 24, spring (April 29 –May 5, summer (September 10–15 and autumn (December 4–8 of 2007 and winter (February 20 – 25 and spring (May 9 –13 of 2008. Extrusa samples were subjected to chemical analysis to determine organic matter (OM, crude protein (CP in situ and in vitro true digestibility of dry matter. OM and CP intake were estimated by total fecal collection. Effective extent of degradation of the OM and CP was calculated hourly and total 24 hours. From the hourly quantity of OM and CP degraded, a synchrony index of CP to OM was calculated, and from the total 24 hours degradation, degraded organic matter intake and crude protein intake were also estimated. Sampling date was the main effect that determined the variation of diet OM and CP degradation parameters. Degraded crude protein intake as a proportion of degraded OM was affected by sampling date and was correlated to rainfall. During winter of the first year degraded crude protein intake was below the requirements for maintenance or to promote growth for range goats weighing 40 kg. Even though, synchrony index between OM and CP degradation was affected by sampling date goats maintained a high synchrony index throughout the years.

  20. Selective Leaching of Dissolved Organic Matter From Alpine Permafrost Soils on the Qinghai-Tibetan Plateau

    Science.gov (United States)

    Wang, Yinghui; Xu, Yunping; Spencer, Robert G. M.; Zito, Phoebe; Kellerman, Anne; Podgorski, David; Xiao, Wenjie; Wei, Dandan; Rashid, Harunur; Yang, Yuanhe

    2018-03-01

    Ongoing global temperature rise has caused significant thaw and degradation of permafrost soils on the Qinghai-Tibetan Plateau (QTP). Leaching of organic matter from permafrost soils to aquatic systems is highly complex and difficult to reproduce in a laboratory setting. We collected samples from natural seeps of active and permafrost layers in an alpine swamp meadow on the QTP to shed light on the composition of mobilized dissolved organic matter (DOM) by combining optical measurements, ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry, radiocarbon (14C), and solid-state 13C nuclear magnetic resonance spectroscopy. Our results show that even though the active layer soils contain large amounts of proteins and carbohydrates, there is a selective release of aromatic components, whereas in the deep permafrost layer, carbohydrate and protein components are preferentially leached during the thawing process. Given these different chemical characteristics of mobilized DOM, we hypothesize that photomineralization contributes significantly to the loss of DOM that is leached from the seasonally thawed surface layer. However, with continued warming, biodegradation will become more important since biolabile materials such as protein and carbohydrate are preferentially released from deep-layer permafrost soils. This transition in DOM leachate source and associated chemical composition has ramifications for downstream fluvial networks on the QTP particularly in terms of processing of carbon and associated fluxes.

  1. Using organic matter to increase soil fertility in Burundi: potentials and limitations

    Science.gov (United States)

    Kaboneka, Salvator

    2015-04-01

    Agriculture production in Burundi is dominated by small scale farmers (0.5 ha/household) who have only very limited access to mineral inputs. In the past, farmers have relied on fallow practices combined with farm yard manures to maintain and improve soil fertility. However, due to the high population growth and high population density (370/km²), fallow practices are nowadays no longer feasible, animal manures cannot be produced in sufficient quantities to maintain soil productivity and food insecurity has become a quasi permanent reality. Most Burundian soils are characterized by 1:1 types of clay minerals (kaolinite) and are acidic in nature. Such soils are of very low cation exchange capacity (CEC). To compare the effect of % clays and % organic matter (% C), correlations tests have been conducted between the two parameters and the CEC. It was found that in high altitude kaolinitic and acidic soils, CEC was highly correlated to % C and less correlated to % clay, suggesting that organic matter could play an important role in improving fertility and productivity of these soils. Based on these findings, additional studies have been conducted to evaluate the fertilizer and soil amendment values of animal manures (cattle, goat, chicken), and leguminous (Calliandra calothyrsus, Gliricidia sepium, Senna simea, Senna spectabilis) and non-leguminous (Tithonia diversifolia) foliar biomass. It was observed that chicken manure significantly reduces Al3+ levels in acidic soils, while Tithonia diversifolia outperforms in nutrient releases compared to the commonly known leguminous agroforestry shrubs and trees indicated above. Although the above mentioned organic sources can contribute to the soil nutrients supply, the quantities potentially available on farm are generally small. The only solution is to supplement these organic sources with other organic sources (compost, organic household waste), chemical fertilizers and mineral amendments (lime) to achieve Integrated Soil

  2. 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.

  3. Riverine organic matter composition and fluxes to Hudson Bay

    Science.gov (United States)

    Kuzyk, Z. Z. A.; Macdonald, R. W.; Goni, M. A.; Godin, P.; Stern, G. A.

    2016-12-01

    With warming in northern regions, many changes including permafrost degradation, vegetation alteration, and wildfire incidence will impact the carbon cycle. Organic carbon (OC) carried by river runoff to northern oceans has the potential to provide integrated evidence of these impacts. Here, concentrations of dissolved (DOC) and particulate (POC) OC are used to estimate terrestrial OC transport in 17 major rivers draining varied vegetative and permafrost conditions into Hudson Bay and compositional data (lignin and 14C) to infer OC sources. Hudson Bay lies just south of the Arctic Circle in Canada and is surrounded by a large drainage basin (3.9 × 106 km2) dominated by permafrost. Analysis of POC and DOC in the 17 rivers indicates that DOC dominates the total OC load. The southern rivers dominate. The Nelson and Churchill Rivers to the southwest are particularly important suppliers of OC partly because of large drainage basins but also perhaps because of impacts by hydroelectric development, as suggested by a 14C age of DOC in the Churchill River of 2800 years. Higher DOC and POC concentrations in the southern rivers, which have substantive areas only partially covered by permafrost, compared to northern rivers draining areas with complete permafrost cover, implies that warming - and hence permafrost thawing - will lead to progressively higher DOC and POC loads for these rivers. Lignin composition in the organic matter (S/V and C/V ratios) reveals mixed sources of OC consistent with the dominant vegetation in the river basins. This vegetation is organized by latitude with southern regions below the tree line enriched by woody gymnosperm sources (boreal forest) and northern regions enriched with organic matter from non-woody angiosperms (flowering shrubs, tundra). Acid/Aldehyde composition together with Δ14C data for selected DOC samples suggest that most of the lignin has undergone oxidative degradation, particularly the DOC component. However, high Δ14C ages

  4. Organic and chemical manure of the bean (Phaseolus vulgaris) in alluvial soils of intermediate climate

    International Nuclear Information System (INIS)

    Tamayo V, Alvaro; Munoz A, Rodrigo

    1997-01-01

    With the purpose to evaluate the effect on bean production ICA CITARA variety, four sources of organic matter (hen manure, pig manure, cow manure, and earthworm manure) in four doses 280,500 y 1.000 kg/ha with the same doses of chemical fertilization, were evaluated the experiment was carried out at Tulio Ospina Research Center, located at Bello (Antioquia) of medium climate with 1.320 m.s.n.m. This was established using an alluvial soil (Tropofluvent), frenk, with low contents of organic, matter (2,2%), phosphorus (10 ppm), and potassium (0,10 meq/l00 g). the results, after six consecutive harvests on the same plots, showed highly significative differences among treatments. The highest yield (1.836 kg/ha) was obtained when to the chemical fertilization (300 kg of 10-30-10) was added with 250 kg/ha of hen manure, followed by the application of 100 kg/ha, of cow manure (1.812 kg/ha). Chemical fertilization without organic matter produced 1.640 kg/ha of bean, which was very similar to the addition of 1.000 kg/ha of cow manure and earthworm manure with yields of 1.688 kg/ha and 1.635 kg/ha respectively

  5. Evolution of organic matter in Orgueil, Murchison and Renazzo during parent body aqueous alteration: In situ investigations

    Science.gov (United States)

    Le Guillou, Corentin; Bernard, Sylvain; Brearley, Adrian J.; Remusat, Laurent

    2014-04-01

    Chondrites accreted the oldest solid materials in the solar system including dust processed in the protoplanetary disk and diverse organic compounds. After accretion, asteroidal alteration may have impacted organic particles in various ways. To constrain these processes, we conducted a comprehensive study of organics disseminated within the matrices of the three carbonaceous chondrite falls, Renazzo (CR2), Murchison (CM2) and Orgueil (CI). By combining synchrotron-based STXM and TEM analyses on FIB sections of samples previously characterized by NanoSIMS, we investigated the influence of aqueous alteration on the morphology, isotopic signature, molecular structure, spatial distribution, and mineralogical environment of the organic matter within the matrices. Two different populations of materials are distinguishable: sub-micrometric individual grains, likely dominated by insoluble compounds and diffuse organic matter, finely interspersed within phyllosilicates and/or (amorphous) nanocarbonates at the nanometer scale. We suggest that this latter component, which is depleted in aromatics and enriched in carboxylic functional groups, may be dominated by soluble compounds. Organic matter in Renazzo (CR) mainly consists of chemically-homogeneous individual grains surrounded by amorphous and nanocrystalline phyllosilicates. Evidence of connectivity between organic grains and fractures indicates that redistribution has occurred: some areas containing diffuse organic matter can be observed. This diffuse organic component is more abundant in Murchison (CM) and Orgueil (CI). This is interpreted as resulting from fluid transport at the micrometer scale and encapsulation within recrystallized alteration phases. In contrast to Renazzo, organic grains in Murchison and Orgueil display strong chemical heterogeneities, likely related to chemical evolution during aqueous alteration. The observations suggest that the altering fluid was a brine with elevated concentrations of both

  6. Synthesis of refractory organic matter in the ionized gas phase of the solar nebula.

    Science.gov (United States)

    Kuga, Maïa; Marty, Bernard; Marrocchi, Yves; Tissandier, Laurent

    2015-06-09

    In the nascent solar system, primitive organic matter was a major contributor of volatile elements to planetary bodies, and could have played a key role in the development of the biosphere. However, the origin of primitive organics is poorly understood. Most scenarios advocate cold synthesis in the interstellar medium or in the outer solar system. Here, we report the synthesis of solid organics under ionizing conditions in a plasma setup from gas mixtures (H2(O)-CO-N2-noble gases) reminiscent of the protosolar nebula composition. Ionization of the gas phase was achieved at temperatures up to 1,000 K. Synthesized solid compounds share chemical and structural features with chondritic organics, and noble gases trapped during the experiments reproduce the elemental and isotopic fractionations observed in primitive organics. These results strongly suggest that both the formation of chondritic refractory organics and the trapping of noble gases took place simultaneously in the ionized areas of the protoplanetary disk, via photon- and/or electron-driven reactions and processing. Thus, synthesis of primitive organics might not have required a cold environment and could have occurred anywhere the disk is ionized, including in its warm regions. This scenario also supports N2 photodissociation as the cause of the large nitrogen isotopic range in the solar system.

  7. Turnover of intra- and extra-aggregate organic matter at the silt-size scale

    Science.gov (United States)

    I. Virto; C. Moni; C. Swanston; C. Chenu

    2010-01-01

    Temperate silty soils are especially sensitive to organic matter losses associated to some agricultural management systems. Long-term preservation of organic C in these soils has been demonstrated to occur mainly in the silt- and clay-size fractions, although our knowledge about the mechanisms through which it happens remains unclear. Although organic matter in such...

  8. Relating hygroscopicity and composition of organic aerosol particulate matter

    CERN Document Server

    Duplissy, J; Prevot, A S H; Barmpadimos, I; Jimenez, J L; Gysel, M; Worsnop, D R; Aiken, A C; Tritscher, T; Canagaratna, M R; Collins, D R; Alfarra, M R; Metzger, A; Tomlinson, J; DeCarlo, P F; Weingartner, E; Baltensperger, U

    2011-01-01

    A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f(44)). m/z 44 is due mostly to the ion fragment CO(2)(+) for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfrau-joch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation b...

  9. Dissolved organic matter in sea spray: a transfer study from marine surface water to aerosols

    Science.gov (United States)

    Schmitt-Kopplin, P.; Liger-Belair, G.; Koch, B. P.; Flerus, R.; Kattner, G.; Harir, M.; Kanawati, B.; Lucio, M.; Tziotis, D.; Hertkorn, N.; Gebefügi, I.

    2012-04-01

    Atmospheric aerosols impose direct and indirect effects on the climate system, for example, by absorption of radiation in relation to cloud droplets size, on chemical and organic composition and cloud dynamics. The first step in the formation of Organic primary aerosols, i.e. the transfer of dissolved organic matter from the marine surface into the atmosphere, was studied. We present a molecular level description of this phenomenon using the high resolution analytical tools of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR). Our experiments confirm the chemoselective transfer of natural organic molecules, especially of aliphatic compounds from the surface water into the atmosphere via bubble bursting processes. Transfer from marine surface water to the atmosphere involves a chemical gradient governed by the physicochemical properties of the involved molecules when comparing elemental compositions and differentiating CHO, CHNO, CHOS and CHNOS bearing compounds. Typical chemical fingerprints of compounds enriched in the aerosol phase were CHO and CHOS molecular series, smaller molecules of higher aliphaticity and lower oxygen content, and typical surfactants. A non-targeted metabolomics analysis demonstrated that many of these molecules corresponded to homologous series of oxo-, hydroxy-, methoxy-, branched fatty acids and mono-, di- and tricarboxylic acids as well as monoterpenes and sugars. These surface active biomolecules were preferentially transferred from surface water into the atmosphere via bubble bursting processes to form a significant fraction of primary organic aerosols. This way of sea spray production leaves a selective biological signature of the surface water in the corresponding aerosol that may be transported into higher altitudes up to the lower atmosphere, thus contributing to the formation of secondary organic aerosol on a global scale or transported laterally with

  10. From bioavailability science to regulation of organic chemicals

    NARCIS (Netherlands)

    Ortega-Calvo, J.J.; Harmsen, J.; Parsons, J.R.; Semple, K.T.; Aitkin, M.D.; Ajao, C.; Eadsforth, C.; Galay-Burgos, M.; Naidu, R.; Oliver, R.; Peijnenburg, W.J.G.M.; Römbke, J.; Streck, G.; Versonnen, B.

    2015-01-01

    The bioavailability of organic chemicals in soil and sediment is an important area of scientific investigation for environmental scientists, although this area of study remains only partially recognized by regulators and industries working in the environmental sector. Regulators have recently

  11. The sorption characteristics of mercury as affected by organic matter content and/or soil properties

    Science.gov (United States)

    Šípková, Adéla; Šillerová, Hana; Száková, Jiřina

    2014-05-01

    The determination and description of the mercury sorption extend on soil is significant for potential environmental toxic effects. The aim of this study was to assess the effectiveness of mercury sorption at different soil samples and vermicomposts. Mercury interactions with soil organic matter were studied using three soils with different physical-chemical properties - fluvisol, cambisol, and chernozem. Moreover, three different vermicomposts based on various bio-waste materials with high organic matter content were prepared in special fermentors. First was a digestate, second was represented by a mixture of bio-waste from housing estate and woodchips, and third was a garden bio-waste. In the case of vermicompost, the fractionation of organic matter was executed primarily using the resin SuperliteTM DAX-8. Therefore, the representation of individual fractions (humic acid, fulvic acid, hydrophilic compounds, and hydrophobic neutral organic matter) was known. The kinetics of mercury sorption onto materials of interest was studied by static sorption experiments. Samples were exposed to the solution with known Hg concentration of 12 mg kg-1 for the time from 10 minutes to 24 hours. Mercury content in the solutions was measured by the inductively coupled plasma mass spectrometry (ICP-MS). Based on this data, the optimum conditions for following sorption experiments were chosen. Subsequently, the batch sorption tests for all soil types and vermicomposts were performed in solution containing variable mercury concentrations between 1 and 12 mg kg-1. Equilibrium concentration values measured in the solution after sorption and calculated mercury content per kilogram of the soil or the vermi-compost were plotted. Two basic models of sorption isotherm - Langmuir and Freundlich, were used for the evaluation of the mercury sorption properties. The results showed that the best sorption properties from studied soil were identified in chernozem with highest cation exchange

  12. Study of Organic Matter in Soils of the Amazon Region Employing Laser Induced Fluorescence Spectroscopy

    Science.gov (United States)

    Tadini, Amanda Maria; Nicolodelli, Gustavo; Mounier, Stéphane; Montes, Célia Regina; Marcondes Bastos Pereira Milori, Débora

    2014-05-01

    In the face of climate change and increasing CO2 levels in the atmosphere, the global carbon cycle, soil organic carbon (SOC) sequestration, and the role of different world biomes as potential sources and sinks of carbon are receiving increasing attention. Carbon quantification is an important environmental indicator, but the structure of organic matter is also important because is related to carbon stability. The synthesis of soil organic matter (SOM), as presented in soils of forest vegetation, can be originated from condensation polymeric polyphenols and quinones that are responsible for controlling the main physical-chemical properties of soils. These systems are present in humic substances, representing the major fluorophore of SOM[1-3]. Abiotic factors, such as soil texture, use and occupation of soil, can influence on the process of SOM formation, molecular structure and in its humification index[4]. Laser Induced Fluorescence Spectroscopy (LIFS) have become a promising technique for assessing humification index of SOM (HLIFS). In this context, the aim of this study was to analyze the humification index of the SOM in the region of Barcelos (Amazon) employing LIFS. The study area was the region of Barcelos, close the river Demeni. The whose vegetation distribution in this area, is two biomes the Dense Ombrophylous Forest (DPQD) and Campinarana (DPQT), with areas of edaphic contacts between these two phytophysiognomies, which ranged from Open field (FDE) to closed Depression (DPQ). Preliminary results showed that the area closed Depression (DPQ) there was a continuous gradient of humification with increasing soil depth. A similar behavior was verified for area Forest (DPQD), where the highest values of HLIFS were obtained between the four points analyzed, indicating the magnitude of the molecular recalcitrance this organic matter in this area. The results obtained for area Campinarana (DPQT) and Open field (FDE) showed an opposite behavior. These points there

  13. Evaluation of the production, composition and aluminum and iron complexation of algogenic organic matter

    Czech Academy of Sciences Publication Activity Database

    Pivokonský, Martin; Klouček, Ondřej; Pivokonská, Lenka

    2006-01-01

    Roč. 40, č. 16 (2006), s. 3045-3052 ISSN 0043-1354 R&D Projects: GA AV ČR KJB200600501 Institutional research plan: CEZ:AV0Z20600510 Keywords : affinity chromatography * algogenic organic matter * aluminum and iron coagulants * extracellular organic matter * molecular weight fractionation * intracellular organic matter Subject RIV: BK - Fluid Dynamics Impact factor: 2.459, year: 2006

  14. Chromophoric dissolved organic matter export from U.S. rivers

    Science.gov (United States)

    Spencer, Robert G. M.; Aiken, George R.; Dornblaser, Mark M.; Butler, Kenna D.; Holmes, R. Max; Fiske, Greg; Mann, Paul J.; Stubbins, Aron

    2013-04-01

    Chromophoric dissolved organic matter (CDOM) fluxes and yields from 15 major U.S. rivers draining an assortment of terrestrial biomes are presented. A robust relationship between CDOM and dissolved organic carbon (DOC) loads is established (e.g., a350 versus DOC; r2 = 0.96, p CDOM yields are also correlated to watershed percent wetland (e.g. a350; r2 = 0.81, p CDOM export from ungauged watersheds. A large variation in CDOM yields was found across the rivers. The two rivers in the north-eastern U.S. (Androscoggin and Penobscot), the Edisto draining into the South Atlantic Bight, and some rivers draining into the Gulf of Mexico (Atchafalaya and Mobile) exhibit the highest CDOM yields, linked to extensive wetlands in these watersheds. If the Edisto CDOM yield is representative of other rivers draining into the South Atlantic Bight, this would result in a CDOM load equivalent to that of the Mississippi from a region of approximately 10% of the Mississippi watershed, indicating the importance of certain regions with respect to the role of terrigenous CDOM in ocean color budgets.

  15. The influence of soluble organic matter on shale reservoir characterization

    Directory of Open Access Journals (Sweden)

    Lei Pan

    2016-06-01

    Full Text Available Shale with a maturity within the “oil window” contains a certain amount of residual soluble organic matter (SOM. This SOM have an important influence on characterization of shale reservoir. In this study, two shale samples were collected from the Upper Permian Dalong Formation in the northwestern boundary of Sichuan Basin. Their geochemistry, mineral composition, and pore structure (surface area and pore volume were investigated before and after removing the SOM by means of extraction via dichloromethane or trichloromethane. The results show that the TOC, S1, S2, and IH of the extracted samples decrease significantly, but the mineral composition has no evident change as compared with their raw samples. Thus, we can infer that the original pore structure is thought to be unaffected from the extraction. The SOM occupies pore volume and hinders pores connectivity. The extraction greatly increases the surface area and pore volume of the samples. The residual SOM in the shale samples occur mainly in the micropores and smaller mesopores, and their occupied pore size range seems being constrained by the maturity. For the lower mature shale samples, the SOM is mainly hosted in organic pores that are less than 5 nm in size. For the middle mature shale samples, the micropores and some mesopores ranging between 2 and 20 nm in size are the main storage space for the SOM.

  16. Chromophoric dissolved organic matter export from U.S. rivers

    Science.gov (United States)

    Spencer, Robert G. M.; Aiken, George R.; Dornblaser, Mark M.; Butler, Kenna D.; Holmes, R. Max; Fiske, Greg; Mann, Paul J.; Stubbins, Aron

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) fluxes and yields from 15 major U.S. rivers draining an assortment of terrestrial biomes are presented. A robust relationship between CDOM and dissolved organic carbon (DOC) loads is established (e.g., a350 versus DOC; r2 = 0.96, p CDOM yields are also correlated to watershed percent wetland (e.g. a350; r2 = 0.81, p CDOM export from ungauged watersheds. A large variation in CDOM yields was found across the rivers. The two rivers in the north-eastern U.S. (Androscoggin and Penobscot), the Edisto draining into the South Atlantic Bight, and some rivers draining into the Gulf of Mexico (Atchafalaya and Mobile) exhibit the highest CDOM yields, linked to extensive wetlands in these watersheds. If the Edisto CDOM yield is representative of other rivers draining into the South Atlantic Bight, this would result in a CDOM load equivalent to that of the Mississippi from a region of approximately 10% of the Mississippi watershed, indicating the importance of certain regions with respect to the role of terrigenous CDOM in ocean color budgets.

  17. Characterization of dissolved organic matter in fogwater by excitation-emission matrix fluorescence spectroscopy

    Science.gov (United States)

    Birdwell, J.E.; Valsaraj, K.T.

    2010-01-01

    Dissolved organic matter (DOM) present in fogwater samples collected in southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix fluorescence spectroscopy. The goal of the study was to illustrate the utility of fluorescence for obtaining information on the large fraction of organic carbon in fogwaters (typically >40% by weight) that defies characterization in terms of specific chemical compounds without the difficulty inherent in obtaining sufficient fogwater volume to isolate DOM for assessment using other spectroscopic and chemical analyses. Based on the findings of previous studies using other characterization methods, it was anticipated that the unidentified organic carbon fraction would have characteristic peaks associated with humic substances and fluorescent amino acids. Both humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices for the fogwater had similar values to those of soil and sediment porewater. Greater biological character was observed in samples with higher organic carbon concentrations. Fogwaters are shown to contain a mixture of terrestrially- and microbially-derived fluorescent organic material, which is expected to be derived from an array of different sources, such as suspended soil and dust particles, biogenic emissions and organic substances generated by atmospheric processes. The fluorescence results indicate that much of the unidentified organic carbon present in fogwater can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems, though it should be noted that fluorescent signatures representative of DOM produced by atmospheric processing of organic aerosols may be contributing to or masked by humic-like fluorophores. ?? 2010.

  18. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge base compost

    International Nuclear Information System (INIS)

    Molina, M. J.; Ingelmo, F.; Soriano, M. D.; Gallardo, A.; Lapena, L.

    2009-01-01

    The agricultural use of anaerobically digested sewage sludge (ADSS) as stable, mature compost implies knowing its total content in heavy metals and their bioavailability. since the chemical form of the metal in the sewage sludge-based compost depends on the effect of stabilization and maturation of the organic material during composting, the objective of this work was to examine the relationships between the changes in the organic matter content and humus fractions, and the bioavailability of heavy metals in a mixture of ADSS and wood chips (70:30 on wet basis) with an initial C/N ratio of 30.4, during its aerobic batch composting at 30 degree centigrade of external temperature in an open type lab-scale reactor with-out lixiviation. (Author)

  19. Influence of organic matter transformations on the bioavailability of heavy metals in a sludge base compost

    Energy Technology Data Exchange (ETDEWEB)

    Molina, M. J.; Ingelmo, F.; Soriano, M. D.; Gallardo, A.; Lapena, L.

    2009-07-01

    The agricultural use of anaerobically digested sewage sludge (ADSS) as stable, mature compost implies knowing its total content in heavy metals and their bioavailability. since the chemical form of the metal in the sewage sludge-based compost depends on the effect of stabilization and maturation of the organic material during composting, the objective of this work was to examine the relationships between the changes in the organic matter content and humus fractions, and the bioavailability of heavy metals in a mixture of ADSS and wood chips (70:30 on wet basis) with an initial C/N ratio of 30.4, during its aerobic batch composting at 30 degree centigrade of external temperature in an open type lab-scale reactor with-out lixiviation. (Author)

  20. Physico-chemical properties of radionuclides emitted as particulate matter

    DEFF Research Database (Denmark)

    Andersson, Kasper Grann

    2016-01-01

    This paper presents work done to improve the representation in European decision support tools of physico-chemical forms of radiocontaminants released to the atmosphere from a major nuclear power plant accident. The task is to accommodate those types of scenarios where fuel particles are at play....

  1. Organic and inorganic speciation of particulate matter formed during different combustion phases in an improved cookstove.

    Science.gov (United States)

    Leavey, Anna; Patel, Sameer; Martinez, Raul; Mitroo, Dhruv; Fortenberry, Claire; Walker, Michael; Williams, Brent; Biswas, Pratim

    2017-10-01

    Residential solid fuel combustion in cookstoves has established health impacts including bladder and lung cancers, cataracts, low birth weight, and pneumonia. The chemical composition of particulate matter (PM) from 4 commonly-used solid fuels (coal, dung, ambient/dry applewood, and oakwood pellets), emitted from a gasifier cookstove, as well as propane, were examined. Temporal changes between the different cookstove burn-phases were also explored. Normalized concentrations of non-refractory PM 1 , total organics, chloride, ammonium, nitrate, sulfate, and 41 particle-phase polycyclic aromatic hydrocarbons (PAHs) were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Thermal desorption Aerosol Gas chromatograph (TAG), respectively. Coal demonstrated the highest fraction of organic matter in its particulate emission composition (98%), followed by dung (94%). Coal and dung also demonstrated the highest numbers and concentrations of PAHs. While dry applewood emitted ten times lower organic matter compared to ambient applewood, a higher fraction of these organics was composed of PAHs, especially the more toxic ones such as benzo(a)pyrene (9.63ng/L versus 0.04ng/L), and benzo(b)fluoranthene (31.32ng/L versus 0.19ng/L). Data from the AMS demonstrated no clear trends for any of the combustion fuels over the different combustion phases unlike the previously reported trends observed for the physical characteristics. Of the solid fuels, pellets demonstrated the lowest emissions. Emissions from propane were below the quantification limit of the instruments. This work highlights the benefits of incorporating additional metrics into the cookstove evaluation process, thus enriching the existing PM data inventory. Copyright © 2017. Published by Elsevier Inc.

  2. Insights in groundwater organic matter from Liquid Chromatography-Organic Carbon Detection

    Science.gov (United States)

    Rutlidge, H.; Oudone, P.; McDonough, L.; Andersen, M. S.; Baker, A.; Meredith, K.; O'Carroll, D. M.

    2017-12-01

    Understanding the processes that control the concentration and characteristics of organic matter in groundwater has important implications for the terrestrial global carbon budget. Liquid Chromatography - Organic Carbon Detection (LC-OCD) is a size-exclusion based chromatography technique that separates the organic carbon into molecular weight size fractions of biopolymers, humic substances, building blocks (degradation products of humic substances), low molecular weight acids and low molecular weight neutrals. Groundwater and surface water samples were collected from a range of locations in Australia representing different surface soil, land cover, recharge type and hydrological properties. At one site hyporheic zone samples were also collected from beneath a stream. The results showed a general decrease in the aromaticity and molecular weight indices going from surface water, hyporheic downwelling and groundwater samples. The aquifer substrate also affected the organic composition. For example, groundwater samples collected from a zone of fractured rock showed a relative decrease in the proportion of humic substances, suggestive of sorption or degradation of humic substances. This work demonstrates the potential for using LC-OCD in elucidating the processes that control the concentration and characteristics of organic matter in groundwater.

  3. Metal-organic frameworks for the removal of toxic industrial chemicals and chemical warfare agents.

    Science.gov (United States)

    Bobbitt, N Scott; Mendonca, Matthew L; Howarth, Ashlee J; Islamoglu, Timur; Hupp, Joseph T; Farha, Omar K; Snurr, Randall Q

    2017-06-06

    Owing to the vast diversity of linkers, nodes, and topologies, metal-organic frameworks can be tailored for specific tasks, such as chemical separations or catalysis. Accordingly, these materials have attracted significant interest for capture and/or detoxification of toxic industrial chemicals and chemical warfare agents. In this paper, we review recent experimental and computational work pertaining to the capture of several industrially-relevant toxic chemicals, including NH 3 , SO 2 , NO 2 , H 2 S, and some volatile organic compounds, with particular emphasis on the challenging issue of designing materials that selectively adsorb these chemicals in the presence of water. We also examine recent research on the capture and catalytic degradation of chemical warfare agents such as sarin and sulfur mustard using metal-organic frameworks.

  4. Physico-chemical properties of indigenous micro organism ...

    African Journals Online (AJOL)

    Paddy husk (PH) and corn stalks (CS) residues are managed through burning. Besides contributing to environmental pollution, burning causes loss of vegetation cover, erosion, run off and loss of organic matter. In order to minimize this problem, a study was conducted to manage PH and CS residues through composting ...

  5. Organic matter in constructed soils from a coal mining area in southern Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Dick, Deborah P.; Avila, Leticia G. [Universidade Federal do Rio Grande do Sul, Inst. de Quimica, Porto Alegre, RS (Brazil); Knicker, Heike [Technische Universitaet Muenchen, Lehrstuhl fuer Bodenkunde, Freising-Weihenstephan (Germany); Inda, Alberto V. Jr.; Giasson, Elvio; Bissani, Carlos A. [Universidade Federal do Rio Grande do Sul, Dept. de Ciencia do Solo, Porto Alegre, RS (Brazil)

    2006-11-15

    In southern Brazil, the landscape restoration after the exhaustion of open cast coal mines involves the filling of mine cavities with both pedogenic and geological material. The objective of this work was to determine the content and chemical composition of the organic matter of two constructed soils (24 years and 2 years) in a coal mining area in southern Brazil. An undisturbed Acrisol and geological material from three sites were also sampled. Samples were analyzed for carbon and nitrogen contents by dry combustion and for chemical composition of the organic matter by {sup 13} C NMR CPMAS and FTIR spectroscopies. Prior to the spectroscopic analyses, the samples were treated with 10% (m/m) hydrofluoric acid solution, which lead to a carbon enrichment in the sample of 2-46 times. The three coal samples were mainly composed of aromatic C (46-63%) and alkyl C (10-28%), and differed largely in the carbon content (18-312 g kg{sup -1}). The C/N ratio of 27 and the proportions of O-alkyl C (26%) and aromatic C (29%) found in the native soil (18 g C kg{sup -1} soil) suggest a coal contamination of the native site. The proportions of O/N-alkyl C (15-17%), alkyl C (22-23%) and aromatic C (39-41%) observed in the organic matter of the A1 horizon of the two constructed soils were intermediate to those of the coal samples and the native soil. In the younger constructed soil the proportion of O/N-alkyl diminished and that of aromatic C increased with depth, whereas in the older constructed soil this trend was less evident. Our results show that, during the 24 years after site reconstruction, the input of vegetation residues diluted the proportion of recalcitrant organic matter. The aromaticity index calculated from the FTIR data (I{sub 1620} /I{sub 2920}) correlated positively with the aryl C/alkyl C ratio, obtained from the NMR data, evidencing the applicability of the FTIR index for geological and coal contaminated samples. (Author)

  6. Formation of mercury sulfide from Hg(II)−thiolate complexes in natural organic matter

    Science.gov (United States)

    Alain Manceau,; Cyprien Lemouchi,; Mironel Enescu,; Anne-Claire Gaillot,; Martine Lanson,; Valerie Magnin,; Pieter Glatzel,; Poulin, Brett; Ryan, Joseph N.; Aiken, George R.; Isabelle Gautier-Lunea,; Kathryn L. Nagy,

    2015-01-01

    Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol-bound mercury with biogenic sulfide, but not in oxic environments. We present experimental evidence that mercury sulfide forms from thiol-bound mercury alone in aqueous dark systems in contact with air. The maximum amount of nanoparticulate mercury sulfide relative to thiol-bound mercury obtained by reacting dissolved mercury and soil organic matter matches that detected in the organic horizon of a contaminated soil situated downstream from Oak Ridge, TN, in the United States. The nearly identical ratios of the two forms of mercury in field and experimental systems suggest a common reaction mechanism for nucleating the mineral. We identified a chemical reaction mechanism that is thermodynamically favorable in which thiol-bound mercury polymerizes to mercury–sulfur clusters. The clusters form by elimination of sulfur from the thiol complexes via breaking of mercury–sulfur bonds as in an alkylation reaction. Addition of sulfide is not required. This nucleation mechanism provides one explanation for how mercury may be immobilized, and eventually sequestered, in oxygenated surface environments.

  7. Organic Matter Responses to Radiation under Lunar Conditions

    Science.gov (United States)

    Matthewman, Richard; Crawford, Ian A.; Jones, Adrian P.; Joy, Katherine H.

    2016-01-01

    Abstract Large bodies, such as the Moon, that have remained relatively unaltered for long periods of time have the potential to preserve a record of organic chemical processes from early in the history of the Solar System. A record of volatiles and impactors may be preserved in buried lunar regolith layers that have been capped by protective lava flows. Of particular interest is the possible preservation of prebiotic organic materials delivered by ejected fragments of other bodies, including those originating from the surface of early Earth. Lava flow layers would shield the underlying regolith and any carbon-bearing materials within them from most of the effects of space weathering, but the encapsulated organic materials would still be subject to irradiation before they were buried by regolith formation and capped with lava. We have performed a study to simulate the effects of solar radiation on a variety of organic materials mixed with lunar and meteorite analog substrates. A fluence of ∼3 × 1013 protons cm−2 at 4–13 MeV, intended to be representative of solar energetic particles, has little detectable effect on low-molecular-weight (≤C30) hydrocarbon structures that can be used to indicate biological activity (biomarkers) or the high-molecular-weight hydrocarbon polymer poly(styrene-co-divinylbenzene), and has little apparent effect on a selection of amino acids (≤C9). Inevitably, more lengthy durations of exposure to solar energetic particles may have more deleterious effects, and rapid burial and encapsulation will always be more favorable to organic preservation. Our data indicate that biomarker compounds that may be used to infer biological activity on their parent planet can be relatively resistant to the effects of radiation and may have a high preservation potential in paleoregolith layers on the Moon. Key Words: Radiation—Moon—Regolith—Amino acids—Biomarkers. Astrobiology 16, 900–912. PMID:27870583

  8. Optimal voxel size for measuring global gray and white matter proton metabolite concentrations using chemical shift imaging

    DEFF Research Database (Denmark)

    Hanson, Lars Peter Grüner; Adalsteinsson, E; Pfefferbaum, A

    2000-01-01

    Quantification of gray and white matter levels of spectroscopically visible metabolites can provide important insights into brain development and pathological conditions. Chemical shift imaging offers a gain in efficiency for estimation of global gray and white matter metabolite concentrations co...

  9. On the chemical reaction of matter with antimatter.

    Science.gov (United States)

    Lodi Rizzini, Evandro; Venturelli, Luca; Zurlo, Nicola

    2007-06-04

    A chemical reaction between the building block antiatomic nucleus, the antiproton (p or H- in chemical notation), and the hydrogen molecular ion (H2+) has been observed by the ATHENA collaboration at CERN. The charged pair interact via the long-range Coulomb force in the environment of a Penning trap which is purpose-built to observe antiproton interactions. The net result of the very low energy collision of the pair is the creation of an antiproton-proton bound state, known as protonium (Pn), together with the liberation of a hydrogen atom. The Pn is formed in a highly excited, metastable, state with a lifetime against annihilation of around 1 micros. Effects are observed related to the temperature of the H2+ prior to the interaction, and this is discussed herein.

  10. Influence of natural mobile organic matter on europium retention on Bure clay rock

    International Nuclear Information System (INIS)

    Vu-Do, Laurence

    2013-01-01

    Bure clay rock (CR) was chosen as host rock for the French high and intermediate level long lived radioactive waste repository. This choice is mostly explained by the retention ability of the Callovo-Oxfordian rock (COx). Bure clay rock contains natural organic matter (OM) that could have an influence on radionuclide retention. The aim of this work is to assess the influence of natural mobile OM on the retention of Eu on clay rock. Eu was chosen as a chemical model for trivalent actinides contained in vitrified waste. Three organic molecules were studied: suberic, sorbic and tiglic acids, small organic acids identified in COx pore water. All the experiments were carried out in an environment recreating COx water (pH=7.5; I=0.1 mol/L; PCO 2 =10 -2 bar).Clay rock sample characterization showed that the sample used in this work was similar to those previously extracted from the area of interest and that it was necessary to maintain pH at 7.5 to avoid altering the clay rock. The Eu-OM system study indicated that organic acids had no influence on Eu speciation in COx water. The Eu-CR system experimental study confirmed that retention implied sorption on CR (C(Eu)≤6.10 -6 mol/L) and precipitation in COx water (C(Eu)≥6.10 -6 mol/L). Distribution coefficient Rd (quantifying sorption) was estimated at 170 ± 30 L/g. This high value is consistent with literature values obtained on clay rocks. The ternary Eu-OM-CR system study showed a slight increase of sorption in the presence of organic matter. This synergistic effect is very satisfactory in terms of storage security: the presence of small organic acids in clay rock does not question retention properties with respect to europium and trivalent actinides. (author)

  11. Bacteria and fluorescent organic matter: processing and production.

    Science.gov (United States)

    Fox, B. G.; Thorn, R. M. S.; Reynolds, D. M.

    2017-12-01

    There is a need for a greater understanding of the importance of aquatic organic matter (OM) within global biogeochemical cycling. This need has prompted characterisation of OM using fluorescence spectroscopy. The origin, transformation and fate of fluorescent organic matter (FOM) is not fully understood within freshwater systems. This work demonstrates the importance of microbial processing in the creation and transformation of FOM, highlighting the dynamics of microbial-FOM interactions, using a model system. The FOM signature of different bacterial species common to surface freshwaters were analysed using a non-fluorescent media; Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa. By undertaking bacterial growth curves, alongside fluorescence spectroscopy, we have been able to determine FOM development in relation to population growth. Within this, we have identified that FOM peaks are associated with different species and driven by bacterial processes, such as cell multiplication or as metabolic by-products. The intracellular and extracellular fluorescence signature of each species has also been analysed to better understand how the microbial community structure may impact the FOM signal in aquatic systems. For example, Peak T develops within the growth curves of all the cultured species and has been identified as both intracellular and extracellular FOM. Whilst Peak T has been termed `microbially-derived' previously, other fluorescence peaks associated with terrestrial high molecular weight compounds, e.g. Peak C, have also been shown to be produced by bacteria throughout growth stages. Additionally, the notion that cell lysis is responsible for the presence of larger FOM compounds was also explored. Our work highlights the capacity of bacteria to not only utilise and process OM but to actively be a source of both labile and recalcitrant OM in situ. The bacteria fluorescence signatures seen are complex with comparable fluorescence peaks to those

  12. Molecular Determinants of Dissolved Organic Matter Reactivity in Lake Water

    Directory of Open Access Journals (Sweden)

    Alina Mostovaya

    2017-12-01

    Full Text Available Lakes in the boreal region have been recognized as the biogeochemical hotspots, yet many questions regarding the regulators of organic matter processing in these systems remain open. Molecular composition can be an important determinant of dissolved organic matter (DOM fate in freshwater systems, but many aspects of this relationship remain unclear due to the complexity of DOM and its interactions in the natural environment. Here, we combine ultrahigh resolution mass spectrometry (FT-ICR-MS with kinetic modeling of decay of >1,300 individual DOM molecular formulae identified by mass spectrometry, to evaluate the role of specific molecular characteristics in decomposition of lake water DOM. Our data is derived from a 4 months microbial decomposition experiment, carried out on water from three Swedish lakes, with the set-up including natural lake water, as well as the lake water pretreated with UV light. The relative decay rate of every molecular formula was estimated by fitting a single exponential model to the change in FT-ICR-MS signal intensities over decomposition time. We found a continuous range of exponential decay coefficients (kexp within different groups of compounds and show that for highly unsaturated and phenolic compounds the distribution of kexp was shifted toward the lowest values. Contrary to this general trend, plant-derived polyphenols and polycondensed aromatics were on average more reactive than compounds with an intermediate aromaticity. The decay rate of aromatic compounds increased with increasing nominal oxidation state of carbon, and molecular mass in some cases showed an inverse relationship with kexp in the UV-manipulated treatment. Further, we observe an increase in formulae-specific kexp as a result of the UV pretreatment. General trends in reactivity identified among major compound groups emphasize the importance of the intrinsic controllers of lake water DOM decay. However, we additionally indicate that each

  13. Dynamics of allochthonous organic matter in a tropical Brazilian headstream

    Directory of Open Access Journals (Sweden)

    José Francisco Gonçalves Júnior

    2006-11-01

    Full Text Available The species composition of the riparian vegetation and the seasonal contribution of input and storage of fine and coarse particulate organic matter were assessed in a 3rd order stretch. Fourteen tree species in the riparian zone were identified, with 3 species contributing with 68% of total litter input: Miconia chartacea Triana (43%, Miconia cyathanthera Triana (16% and Erythroxylum pelletarianum St. Hil (9%. The allochthonous input of coarse particulate organic matter (CPOM was composed mainly by leaves (over 50%. Species composition and the contribution of each plant species biomass for vertical, lateral and soil inputs and benthic stocks varied along the study period. The maximum values found in September, November and December coincided with the beginning of the rainy season. There were no differences between the allochthonous vertical and lateral inputs of CPOM to the stream. Differently to other studies, this result was probably due to the peculiar composition of stream’s riparian vegetation at Serra do Cipó.Foram determinadas as espécies que compõem a vegetação ripária e avaliada a variação sazonal da entrada e o estoque de matéria orgânica particulada grossa (MOPG em um trecho de 3ª ordem. Três espécies dentre 14 identificadas foram as mais abundantes na região ripária: Miconia chartacea Triana (43%, Miconia cyathanthera Triana (16% and Erythroxylum pelletarianum St. Hil (9%. A matéria orgânica particulada alóctone foi composta principalmente por folhas (acima de 50% Foi observado que MOPG e MOPF no estoque bêntico aumentou de julho a dezembro de 2001, sendo mais elevado em setembro, novembro e dezembro com o início da estação chuvosa. A composição de espécies e a biomassa de cada espécie no aporte de matéria orgânica vertical, lateral, no solo e estoque bêntico variaram ao longo do período estudado. Não foram encontradas diferenças significativas entre os aportes de matéria orgânica vertical, lateral

  14. Measuring organic matter in Everglades wetlands and the Everglades Agricultural Area

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Alan L. [Univ. of Florida, Gainesville, FL (United States); Hanlon, Edward A. [Univ. of Florida, Gainesville, FL (United States)

    2015-01-01

    Here, organic matter is a complex material that represents the long-term decay products from plants and other organisms in the soil. When organic matter is allowed to build up in a soil, the soil color at the surface usually turns a darker color, often with a red or brown hue. Typically in Florida mineral soils, organic matter content is quite low, within the range of 1 to 5%. However, in some soils that remain flooded for most of the year, organic matter can build up with time and actually become the soil. Such is the case for the organic soils, or histosols, found in southern Florida. These organic soils comprise much of the Water Conservation Areas, Everglades National Park (ENP), Big Cypress Basin, and the Everglades Agricultural Area (EAA). It is important to document organic matter accumulation in the Everglades to gauge the effectiveness of wetland creation and succession. For the EAA, the drained soils lose organic matter due to oxidation, so measurement of the organic matter content of these soils over the course of time indicates the oxidation potential and mineral incorporation from bedrock. Due to the wide diversity of soil types and methods of measuring soil organic matter, there is a need to devise a more universal method applicable to many types of histosols in south Florida. The intent of this publication is: 1.To describe a simple laboratory method for determining the organic matter content of the organic soils of southern Florida and demonstrate the importance of using this new procedure for improved accuracy and precision; 2.To utilize this updated laboratory procedure for field sites across Everglades wetlands and the EAA; and 3. To recommend this procedure be used by growers, state and federal agencies, and university and agency researchers dealing with the management of organic soils in southern Florida. Growers can use this improvement to organic matter measurement to keep lab testing costs low while getting a better, more quantitative

  15. Advanced characterization of dissolved organic matter released by bloom-forming marine algae

    KAUST Repository

    Rehman, Zahid Ur

    2017-06-01

    Algal organic matter (AOM), produced by marine phytoplankton during bloom periods, may adversely affect the performance of membrane processes in seawater desalination. The polysaccharide fraction of AOM has been related to (bio)fouling in micro-filtration and ultrafiltration, and reverse osmosis membranes. However, so far, the chemical structure of the polysaccharides released by bloom-forming algae is not well understood. In this study, dissolved fraction of AOM produced by three algal species (Chaetoceros affinis, Nitzschia epithemoides and Hymenomonas spp.) was characterized using liquid chromatography–organic carbon detection (LC-OCD) and fluorescence spectroscopy. Chemical structure of polysaccharides isolated from the AOM solutions at stationary phase was analyzed using proton nuclear magnetic resonance (H-NMR). The results showed that production and composition of dissolved AOM varied depending on algal species and their growth stage. AOM was mainly composed of biopolymers (BP; i.e., polysaccharides and proteins [PN]), but some refractory substances were also present.H-NMR spectra confirmed the predominance of carbohydrates in all samples. Furthermore, similar fingerprints were observed for polysaccharides of two diatom species, which differed considerably from that of coccolithophores. Based on the findings of this study,H-NMR could be used as a method for analyzing chemical profiles of algal polysaccharides to enhance the understanding of their impact on membrane fouling.

  16. Bismuth solubility through binding by various organic compounds and naturally occurring soil organic matter.

    Science.gov (United States)

    Murata, Tomoyoshi

    2010-01-01

    The present study was performed to examine the effects of soluble organic matter and pH on the solubility of Bi in relation to inference with the behavior of metallic Bi dispersed in soil and water environments using EDTA, citric acid, tartaric acid, L-cysteine, soil humic acids (HA), and dissolved organic matter (DOM) derived from the soil organic horizon. The solubility of Bi by citric acid, tartaric acid, L-cysteine, HA, and DOM showed pH dependence, while that by EDTA did not. Bi solubility by HA seemed to be related to the distribution of pKa (acid dissociation constant) values of acidic functional groups in their molecules. That is, HA extracted at pH 3.2 solubilized Bi preferentially in the acidic range, while HA extracted at pH 8.4 showed preferential solubilization at neutral and alkaline pH. This was related to the dissociation characteristics of functional groups, their binding capacity with Bi, and precipitation of Bi carbonate or hydroxides. In addition to the dissociation characteristics of functional groups, the unique structural configuration of the HA could also contribute to Bi-HA complex formation. The solubility of Bi by naturally occurring DOM derived from the soil organic horizon (Oi) and its pH dependence were different from those associated with HA and varied among tree species.

  17. Cosorption study of organic pollutants and dissolved organic matter in a soil

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Cespedes, F. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain); Fernandez-Perez, M. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain)]. E-mail: mfernand@ual.es; Villafranca-Sanchez, M. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain); Gonzalez-Pradas, E. [Department of Inorganic Chemistry, University of Almeria, La Canada de San Urbano s/n, 04120 Almeria (Spain)

    2006-08-15

    In this study we have evaluated the effects of dissolved organic matter (DOM) on sorption of imidacloprid, 3,4-dichloroaniline (3,4-DCA) and 4-bromoaniline (4-BA) on a typical calcareous soil (Luvic Xerosol) from south-eastern Spain. Two different types of DOM were used, that is to say, dissolved natural organic matter extracts from a commercial peat (DNOM) and a high-purity tannic acid (TA) solution. The experiments were carried out in a 0.01 M CaCl{sub 2} aqueous medium at 25 deg. C. The results indicated that the presence of both DNOM and TA, over a concentration range of 15-100 mg L{sup -1}, produced an increase in the amount of 3,4-DCA and 4-BA sorbed and a decrease in the amount of imidacloprid retained on the soil studied. A modified distribution coefficient, K {sub doc}, has been proposed as a safer parameter for soil sorption predictions of organic pollutants and it could be of help to model the fate of these in the environment. - Cosorption of organic pollutants and DOM.

  18. Cosorption study of organic pollutants and dissolved organic matter in a soil

    International Nuclear Information System (INIS)

    Flores-Cespedes, F.; Fernandez-Perez, M.; Villafranca-Sanchez, M.; Gonzalez-Pradas, E.

    2006-01-01

    In this study we have evaluated the effects of dissolved organic matter (DOM) on sorption of imidacloprid, 3,4-dichloroaniline (3,4-DCA) and 4-bromoaniline (4-BA) on a typical calcareous soil (Luvic Xerosol) from south-eastern Spain. Two different types of DOM were used, that is to say, dissolved natural organic matter extracts from a commercial peat (DNOM) and a high-purity tannic acid (TA) solution. The experiments were carried out in a 0.01 M CaCl 2 aqueous medium at 25 deg. C. The results indicated that the presence of both DNOM and TA, over a concentration range of 15-100 mg L -1 , produced an increase in the amount of 3,4-DCA and 4-BA sorbed and a decrease in the amount of imidacloprid retained on the soil studied. A modified distribution coefficient, K doc , has been proposed as a safer parameter for soil sorption predictions of organic pollutants and it could be of help to model the fate of these in the environment. - Cosorption of organic pollutants and DOM

  19. Membrane-Organized Chemical Photoredox Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, James K.

    2014-09-18

    This project has three interrelated goals relevant to solar water photolysis, which are to develop: (1) vesicle-organized assemblies for H2 photoproduction that utilize pyrylium and structurally related compounds as combined photosensitizers and cyclic electroneutral transmembrane electron carriers; (2) transmembrane redox systems whose reaction rates can be modulated by light; and (3) homogeneous catalysts for water oxidation. . In area (1), initial efforts to photogenerate H2 from vectorially-organized vesicles containing occluded colloidal Pt and commonly available pyrylium ions as transmembrane redox mediators were unsuccessful. New pyrylium compounds with significantly lower reduction potentials have been synthesized to address this problem, their apparent redox potentials in functioning systems have been now evaluated by using a series of occluded viologens, and H2 photoproduction has been demonstrated in continuous illumination experiments. In area (2), spirooxazine-quinone dyads have been synthesized and their capacity to function as redox mediators across bilayer membranes has been evaluated through continuous photolysis and transient spectrophotometric measurements. Photoisomerization of the spiro moiety to the ring-open mero form caused net quantum yields to decrease significantly, providing a basis for photoregulation of transmembrane redox. Research on water oxidation (area 3) has been directed at understanding mechanisms of catalysis by cis,cis-[(bpy)2Ru(OH2)]2O4+ and related polyimine complexes. Using a variety of physical techniques, we have: (i) identified the redox state of the complex ion that is catalytically active; (ii) shown using 18O isotopic labeling that there are two reaction pathways, both of which involve participation of solvent H2O; and (iii) detected and characterized by EPR and resonance Raman spectroscopies new species which may be key intermediates in the catalytic cycle.

  20. Occupational chemical exposures in artificial organic fiber industries

    Energy Technology Data Exchange (ETDEWEB)

    Guirguis, S S; Cohen, M B

    1984-05-01

    This review discusses artificial organic fibers that are produced from materials of natural origin such as rayons, cellulose triacetates and proteins; or made from polymerised chemicals such as polyamides, polyesters, polyvinyls, modacrylics, carbon fibers, polyolefins, polyurethane and polytetrafluoroethylene. Chemicals involved include monomers, solvents, flame retardants, pigments and other additives. Occupational exposure to chemicals in the production stages are discussed and also the potential health hazards involved are reviewed. Current exposure levels, engineering controls and work practices for some of the chemicals used in the Ontario artificial fiber industry are discussed. Recommendations are made for areas that need further study and/or investigation.

  1. Organic management and cover crop species steer soil microbial community structure and functionality along with soil organic matter properties

    NARCIS (Netherlands)

    Martínez-García, Laura B.; Korthals, Gerard; Brussaard, Lijbert; Jørgensen, Helene Bracht; Deyn, de Gerlinde B.

    2018-01-01

    It is well recognized that organic soil management stimulates bacterial biomass and activity and that including cover crops in the rotation increases soil organic matter (SOM). Yet, to date the relative impact of different cover crop species and organic vs. non-organic soil management on soil

  2. PHYS: Division of Physical Chemistry 258 - Properties and Origins of Cometary and Asteroidal Organic Matter Delivered to the Early Earth

    Science.gov (United States)

    Messenger, Scott; Nguyen, Ann

    2017-01-01

    Comets and asteroids may have contributed much of the Earth's water and organic matter. The Earth accretes approximately 4x10(exp 7) Kg of dust and meteorites from these sources every year. The least altered meteorites contain complex assemblages of organic compounds and abundant hydrated minerals. These carbonaceous chondrite meteorites probably derive from asteroids that underwent hydrothermal processing within the first few million years after their accretion. Meteorite organics show isotopic and chemical signatures of low-T ion-molecule and grain-surface chemistry and photolysis of icy grains that occurred in cold molecular clouds and the outer protoplanetary disk. These signatures have been overprinted by aqueously mediated chemistry in asteroid parent bodies, forming amino acids and other prebiotic molecules. Comets are much richer in organic matter but it is less well characterized. Comet dust collected in the stratosphere shows larger H and N isotopic anomalies than most meteorites, suggesting better preservation of primordial organics. Rosetta studies of comet 67P coma dust find complex organic matter that may be related to the macromolecular material that dominates the organic inventory of primitive meteorites. The exogenous organic material accreting on Earth throughout its history is made up of thousands of molecular species formed in diverse processes ranging from circumstellar outflows to chemistry at near absolute zero in dark cloud cores and the formative environment within minor planets. NASA and JAXA are currently flying sample return missions to primitive, potentially organic-rich asteroids. The OSIRIS-REx and Hayabusa2 missions will map their target asteroids, Bennu and Ryugu, in detail and return regolith samples to Earth. Laboratory analyses of these pristine asteroid samples will provide unprecedented views of asteroidal organic matter relatively free of terrestrial contamination within well determined geological context. Studies of

  3. Spatiotemporal Characterization of Chromophoric Dissolved Organic Matter (CDOM) and CDOM-DOC Relationships for Highly Polluted Rivers

    OpenAIRE

    Sijia Li; Jiquan Zhang; Guangyi Mu; Hanyu Ju; Rui Wang; Danjun Li; Ali Hassan Shabbir

    2016-01-01

    Spectral characteristics of CDOM (Chromophoric dissolved organic matter) in water columns are a key parameter for bio-optical modeling. Knowledge of CDOM optical properties and spatial discrepancy based on the relationship between water quality and spectral parameters in the Yinma River watershed with in situ data collected from highly polluted waters are exhibited in this study. Based on the comprehensive index method, the riverine waters showed serious contamination; especially the chemical...

  4. Removal of trace organic chemical contaminants by a membrane bioreactor.

    Science.gov (United States)

    Trinh, T; van den Akker, B; Stuetz, R M; Coleman, H M; Le-Clech, P; Khan, S J

    2012-01-01

    Emerging wastewater treatment processes such as membrane bioreactors (MBRs) have attracted a significant amount of interest internationally due to their ability to produce high quality effluent suitable for water recycling. It is therefore important that their efficiency in removing hazardous trace organic contaminants be assessed. Accordingly, this study investigated the removal of trace organic chemical contaminants through a full-scale, package MBR in New South Wales, Australia. This study was unique in the context of MBR research because it characterised the removal of 48 trace organic chemical contaminants, which included steroidal hormones, xenoestrogens, pesticides, caffeine, pharmaceuticals and personal care products (PPCPs). Results showed that the removal of most trace organic chemical contaminants through the MBR was high (above 90%). However, amitriptyline, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, omeprazole, sulphamethoxazole and trimethoprim were only partially removed through the MBR with the removal efficiencies of 24-68%. These are potential indicators for assessing MBR performance as these chemicals are usually sensitive to changes in the treatment systems. The trace organic chemical contaminants detected in the MBR permeate were 1 to 6 orders of magnitude lower than guideline values reported in the Australian Guidelines for Water Recycling. The outcomes of this study enhanced our understanding of the levels and removal of trace organic contaminants by MBRs.

  5. Study of the interactions between organic matter and transuranic elements

    International Nuclear Information System (INIS)

    Moulin, V.; Billon, A.; Theyssier, M.; Dellis, T.

    1991-01-01

    The study of the occurrence of humic substances present in natural waters and their physico-chemical properties, in particular their complexing behaviour, constitutes the main objectives of this research programme. In the first part, the report presents the description of the selected aquifer (representative of a granitic geological formation: Fanay-Augeres), the method for the collection and concentration of the humic substances (a sorption technique) and their characterization by different physico-chemical techniques (elementary and mineral composition, spectroscopic properties, size, proton capacity, datation). The results show that Fanay-Augeres humic substances (considered as site-specific humic substances) represent 41% of the total organic carbon (TOC) present in the aquifer (2ppm) and have properties similar to other aquatic humic substances. The second part describes the study of the interactions occurring between these humic substances and trivalent cations (Eu and Am). Two different analytical methods have been developed to perform these investigations: spectrophotometry and size-exclusion chromatography. Interaction constants and complexing capacities have been determined and compared with literature data. Fanay-Augeres humic substances present complexing for trivalent actinides which agrees with published data. Further developments needed in complexation studies are described. 10 figs.; 15 tabs.; 39 refs

  6. Anthropogenic inputs of dissolved organic matter in New York Harbor

    Science.gov (United States)

    Gardner, G. B.; Chen, R. F.; Olavasen, J.; Peri, F.

    2016-02-01

    The Hudson River flows into the Atlantic Ocean through a highly urbanized region which includes New York City to the east and Newark, New Jersey to the west. As a result, the export of Dissolved Organic Carbon (DOC) from the Hudson to the Atlantic Ocean includes a significant anthropogenic component. A series of high resolution studies of the DOC dynamics of this system were conducted between 2003 and 2010. These included both the Hudson and adjacent large waterways (East River, Newark Bay, Kill Van Kull and Arthur Kill) using coastal research vessels and smaller tributaries (Hackensack, Pasaic and Raritan rivers) using a 25' boat. In both cases measurements were made using towed instrument packages which could be cycled from near surface to near bottom depths with horizontal resolution of approximately 20 to 200 meters depending on depth and deployment strategy. Sensors on the instrument packages included a CTD to provide depth and salinity information and a chromophoric dissolved organic matter(CDOM) fluorometer to measure the fluorescent fraction of the DOC. Discrete samples allowed calibration of the fluorometer and the CDOM data to be related to DOC. The combined data set from these cruises identified multiple scales of source and transport processes for DOC within the Hudson River/New York Harbor region. The Hudson carries a substantial amount of natural DOC from its 230 km inland stretch. Additional sources exist in fringing salt marshes adjacent to the Hackensack and Raritan rivers. However the lower Hudson/New Harbor region receives a large input of DOC from multiple publically owned treatment works (POTW) discharges. The high resolution surveys allowed us to elucidate the distribution of these sources and the manner in which they are rapidly mixed to create the total export. We estimate that anthropogenic sources account for up to 2.5 times the DOC flux contributed by natural processes.

  7. Dissolved Organic Matter Land-Ocean Linkages in the Arctic

    Science.gov (United States)

    Mann, P. J.; Spencer, R. M.; Hernes, P. J.; Tank, S. E.; Striegl, R.; Dyda, R. Y.; Peterson, B. J.; McClelland, J. W.; Holmes, R. M.

    2012-04-01

    Rivers draining into the Arctic Ocean exhibit high concentrations of terrigenous dissolved organic carbon (DOC), and recent studies indicate that DOC export is changing due to climatic warming and alteration in permafrost condition. The fate of exported DOC in the Arctic Ocean is important for understanding the regional carbon cycle and remains a point of discussion in the literature. As part of the NSF funded Arctic Great Rivers Observatory (Arctic-GRO) project, samples were collected for DOC, chromophoric and fluorescent dissolved organic matter (CDOM & FDOM) and lignin phenols from the Ob', Yenisey, Lena, Kolyma, Mackenzie and Yukon rivers in 2009 - 2010. DOC and lignin concentrations were elevated during the spring freshet and measurements related to DOC composition indicated an increasing contribution from terrestrial vascular plant sources at this time of year (e.g. lignin carbon-normalized yield, CDOM spectral slope, SUVA254, humic-like fluorescence). CDOM absorption was found to correlate strongly with both DOC (r2=0.83) and lignin concentration (r2=0.92) across the major arctic rivers. Lignin composition was also successfully modeled using FDOM measurements decomposed using PARAFAC analysis. Utilizing these relationships we modeled loads for DOC and lignin export from high-resolution CDOM measurements (daily across the freshet) to derive improved flux estimates, particularly from the dynamic spring discharge maxima period when the majority of DOC and lignin export occurs. The new load estimates for DOC and lignin are higher than previous evaluations, emphasizing that if these are more representative of current arctic riverine export, terrigenous DOC is transiting through the Arctic Ocean at a faster rate than previously thought. It is apparent that higher resolution sampling of arctic rivers is exceptionally valuable with respect to deriving accurate fluxes and we highlight the potential of CDOM in this role for future studies and the applicability of in

  8. Organic matter and salinity modify cadmium soil (phyto)availability.

    Science.gov (United States)

    Filipović, Lana; Romić, Marija; Romić, Davor; Filipović, Vilim; Ondrašek, Gabrijel

    2018-01-01

    Although Cd availability depends on its total concentration in soil, it is ultimately defined by the processes which control its mobility, transformations and soil solution speciation. Cd mobility between different soil fractions can be significantly affected by certain pedovariables such as soil organic matter (SOM; over formation of metal-organic complexes) and/or soil salinity (over formation of metal-inorganic complexes). Phytoavailable Cd fraction may be described as the proportion of the available Cd in soil which is actually accessible by roots and available for plant uptake. Therefore, in a greenhouse pot experiment Cd availability was observed in the rhizosphere of faba bean exposed to different levels of SOM, NaCl salinity (50 and 100mM) and Cd contamination (5 and 10mgkg -1 ). Cd availability in soil does not linearly follow its total concentration. Still, increasing soil Cd concentration may lead to increased Cd phytoavailability if the proportion of Cd 2+ pool in soil solution is enhanced. Reduced Cd (phyto)availability by raised SOM was found, along with increased proportion of Cd-DOC complexes in soil solution. Data suggest decreased Cd soil (phyto)availability with the application of salts. NaCl salinity affected Cd speciation in soil solution by promoting the formation of CdCl n 2-n complexes. Results possibly suggest that increased Cd mobility in soil does not result in its increased availability if soil adsorption capacity for Cd has not been exceeded. Accordingly, chloro-complex possibly operated just as a Cd carrier between different soil fractions and resulted only in transfer between solid phases and not in increased (phyto)availability. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. The effects of organic matter-mineral interactions and organic matter chemistry on diuron sorption across a diverse range of soils.

    Science.gov (United States)

    Smernik, Ronald J; Kookana, Rai S

    2015-01-01

    Sorption of non-ionic organic compounds to soil is usually expressed as the carbon-normalized partition coefficient (KOC), because it is assumed that the main factor that influences the amount sorbed is the organic carbon content of the soil. However, KOC can vary by a factor of at least ten across a range of soils. We investigated two potential causes of variation in diuron KOC - organic matter-mineral interactions and organic matter chemistry - for a diverse set of 34 soils from Sri Lanka, representing a wide range of soil types. Treatment with hydrofluoric acid (HF-treatment) was used to concentrate soil organic matter. HF-treatment increased KOC for the majority of soils (average factor 2.4). We attribute this increase to the blocking of organic matter sorption sites in the whole soils by minerals. There was no significant correlation between KOC for the whole soils and KOC for the HF-treated soils, indicating that the importance of organic matter-mineral interactions varied greatly amongst these soils. There was as much variation in KOC across the HF-treated soils as there was across the whole soils, indicating that the nature of soil organic matter is also an important contributor to KOC variability. Organic matter chemistry, determined by solid-state (13)C nuclear magnetic resonance (NMR) spectroscopy, was correlated with KOC for the HF-treated soils. In particular, KOC increased with the aromatic C content (R=0.64, p=1×10(-6)), and decreased with O-alkyl C (R=-0.32, p=0.03) and alkyl C (R=-0.41, p=0.004) content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Passive sampler for dissolved organic matter in freshwater environments.

    Science.gov (United States)

    Lam, Buuan; Simpson, André J

    2006-12-15

    A passive sampler for the isolation of dissolved organic matter (DOM) from freshwater environments is described. The sampler consists of a molecular weight selective membrane (1000 kDa) and an anion exchange resin (diethylaminoethylcellulose (DEAE-cellulose)). NMR indicates the samplers isolate DOM that is nearly indistinguishable from that isolated using the batch DEAE-cellulose procedure. In a comparative study DOM isolated from Lake Ontario cost approximately 0.30 dollars/mg to isolate using the passive samplers while DOM isolated using the traditional batch procedure cost approximately 8-10 dollars/mg. The samplers have been shown to be effective in a range of freshwater environments including a large inland lake (Lake Ontario), fast flowing tributary, and wetland. Large amounts (gram quantities of DOM) can be easily isolated by increasing the size or number of samplers deployed. Samplers are easy to construct, negate the need for pressure filtering, and also permit a range of temporal and spatial experiments that would be very difficult or impossible to perform using conventional approaches. For example, DOM can be monitored on a regular basis at numerous different locations, or samplers could be set at different depths in large lakes. Furthermore, they could potentially be deployed into hard to reach environments such as wells, groundwater aquifers, etc., and as they are easy to use, they can be mailed to colleagues or included with expeditions going to difficult to reach places such as the Arctic and Antarctic.

  11. Interaction of uranium and organic matter in unaniferous sediments

    Energy Technology Data Exchange (ETDEWEB)

    Rouzaud, J N; Oberlin, A; Trichet, J

    1980-01-01

    Conventional transmission electron microscopy (lattice fringes and dark field techniques) was used for determining the structure and microtexture of some Precambrian organic matter. The samples came from Cluff (Saskatchewan, Canada) and Oklo (Gabon) and contain uranium with organo-metallic bonding (uranium was shown to be present by energy dispersive X-ray analysis carried out in the CTEM). Despite their algal origin, these materials show a high oxygen content. This strong degree of oxidation inhibits the parallel molecular orientation usually produced in carbonaceous products as coalification progresses. Progressive heat-treatment to 3000/sup 0/C produces microporous carbon (50 to 100A). It is, however, partially transformed into graphite in a manner similar to anthracites and non-graphitizable carbons heat-treated under pressure (5 kbars). It is favored by pore flattening, due to pressure, which introduces a long-range, preferred orientation parallel to the flattening plane. Conversely, it is partially prevented by cross-linking due to oxygen. Comparison with materials of higher plant origin (e.g. from Arlit, Niger) suggests a possible mechanism of uranium fixation.

  12. Sorption-desorption dynamics of radiocaesium in organic matter soils

    International Nuclear Information System (INIS)

    Valcke, E.; Cremers, A.

    1994-01-01

    A systematic study has been carried out on the radiocaesium sorption properties of 25 soils (forest, peat) covering organic matter (OM) contents in the range of 10-97%. Predictions are made for radiocaesium partitioning between micaceous Frayed Edge Sites (FES) and regular exchange sites (RES) on the basis of specific radiocaesium interception potentials of the soil and overall exchange capacity. It is shown that for soils with a very high OM content (>80%), significant fractions are present in a readily reversible form in the OM phase. In soils of low-medium OM content (<40%), only a very minor fraction is present in the OM exchange complex. Experimental findings, based on a desorption screening with a variety of desorption agents are in agreement with these predictions. On the basis of a study of sorption kinetics, some additional tools are available for identifying problem soils. In cases of very high OM content, radiocaesium adsorption is completed within hours demonstrating the involvement of the OM sites. In soils for which interception occurs in the FES, sorption continues to proceed for periods of 2-3 weeks. In conclusion, some examples are presented on radiocaesium desorption using ion exchangers as radiocaesium sinks in promoting desorption. For a peaty soil, near quantitative desorption is accomplished. For forest soils with OM contents in a range of 10-40%, fixation levels of 30-50% are demonstrated

  13. Peat decomposability in managed organic soils in relation to land use, organic matter composition and temperature

    Science.gov (United States)

    Bader, Cédric; Müller, Moritz; Schulin, Rainer; Leifeld, Jens

    2018-02-01

    Organic soils comprise a large yet fragile carbon (C) store in the global C cycle. Drainage, necessary for agriculture and forestry, triggers rapid decomposition of soil organic matter (SOM), typically increasing in the order forest accrual of labile crop residues. A comparison with published CO2 rates from incubated mineral soils indicated no difference in SOM decomposability between these soil classes, suggesting that accumulation of recent, labile plant materials that presumably account for most of the evolved CO2 is not systematically different between mineral and organic soils. In our data set, temperature sensitivity of decomposition (Q10 on average 2.57 ± 0.05) was the same for all land uses but lowest below 60 cm in croplands and grasslands. This, in turn, indicates a relative accumulation of recalcitrant peat in topsoils.

  14. Distribution of some organic components in two forest soils profiles with evidence of soil organic matter leaching.

    Science.gov (United States)

    Álvarez-Romero, Marta; Papa, Stefania; Lozano-García, Beatriz; Parras-Alcántara, Luis; Coppola, Elio

    2015-04-01

    Soil stores organic carbon more often than we can find in living vegetation and atmosphere together. This reservoir is not inert, but it is constantly in a dynamic phase of inputs and losses. Soil organic carbon mainly depends on land cover, environment conditions and soil properties. After soil deposition, the organic residues of different origin and nature, the Soil Organic Matter (SOM) can be seen involved in two different processes during the pedogenesis: mineralization and humification. The transport process along profile happens under certain conditions such as deposition of high organic residues amount on the top soil, high porosity of the soil caused by sand or skeleton particles, that determine a water strong infiltrating capacity, also, extreme temperatures can slow or stop the mineralization and/or humification process in one intermediate step of the degradation process releasing organic metabolites with high or medium solubility and high loads of water percolating in relation to intense rainfall. The transport process along soil profile can take many forms that can end in the formation of Bh horizons (h means accumulation of SOM in depth). The forest cover nature influence to the quantity and quality of the organic materials deposited with marked differences between coniferous and deciduous especially in relation to resistance to degradation. Two soils in the Campania region, located in Lago Laceno (Avellino - Italy) with different forest cover (Pinus sp. and Fagus sp.) and that meets the requirements of the place and pedological formation suitable for the formation and accumulation of SOM in depth (Bh horizon) were studied. The different soil C fractions were determinated and were assessed (Ciavatta C. et al. 1990; Dell'Abate M.T. et al. 2002) for each soil profile the Total Extractable Lipids (TEL). Furthermore, the lignin were considered as a major component of soil organic matter (SOM), influencing its pool-size and its turnover, due to the high

  15. Spatial arrangement of organic compounds on a model mineral surface: implications for soil organic matter stabilization.

    Science.gov (United States)

    Petridis, Loukas; Ambaye, Haile; Jagadamma, Sindhu; Kilbey, S Michael; Lokitz, Bradley S; Lauter, Valeria; Mayes, Melanie A

    2014-01-01

    The complexity of the mineral-organic carbon interface may influence the extent of stabilization of organic carbon compounds in soils, which is important for global climate futures. The nanoscale structure of a model interface was examined here by depositing films of organic carbon compounds of contrasting chemical character, hydrophilic glucose and amphiphilic stearic acid, onto a soil mineral analogue (Al2O3). Neutron reflectometry, a technique which provides depth-sensitive insight into the organization of the thin films, indicates that glucose molecules reside in a layer between Al2O3 and stearic acid, a result that was verified by water contact angle measurements. Molecular dynamics simulations reveal the thermodynamic driving force behind glucose partitioning on the mineral interface: The entropic penalty of confining the less mobile glucose on the mineral surface is lower than for stearic acid. The fundamental information obtained here helps rationalize how complex arrangements of organic carbon on soil mineral surfaces may arise.

  16. Micropore characteristics of organic matter pools in cemented and non-cemented podzolic horizons

    NARCIS (Netherlands)

    Catoni, M.; D'amico, M.E.; Mittelmeijer-Hazeleger, M.C.; Rothenberg, G.; Bonifacio, E.

    2014-01-01

    In Podzols, organic matter (OM) is stabilized mainly by interaction with minerals, as a direct consequence of pedogenic processes. Metal-organic associations strongly affect OM surface features, particularly microporosity. Cemented ortstein horizons (CM) may form during podzolization, accompanied by

  17. Changes in functional organization and white matter integrity in the connectome in Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Sule Tinaz

    2017-01-01

    Our results suggest that despite subtle white matter connectivity changes, the overall structural organization of the PD connectome remains robust at relatively early disease stages. However, there is a breakdown in the functional modular organization of the PD connectome.

  18. Factors influencing the characteristics and distribution or surface organic matter in the Pacific-Atlantic connection

    Science.gov (United States)

    Barrera, Facundo; Lara, Rubén J.; Krock, Bernd; Garzón-Cardona, John Edison; Fabro, Elena; Koch, Boris P.

    2017-11-01

    The present work reports the first data set on particulate organic carbon (POC) and nitrogen (PON), and the high-resolution modelling of their stable isotope variability in the Patagonian Cold Estuarine System (PCES), with focus on particulate organic matter (POM) origin and distribution in dependence on physical, chemical and biological parameters. POC, PON, stable carbon (δ13C) and nitrogen isotopes (δ15N), dissolved organic nitrogen, phaeopigments, diatom, dinoflagellate and heterotrophic bacteria (HB) abundance are reported for 17 stations in different waters masses in the southern end of the Argentine shelf in late summer 2012. Most parameters denote clear differences between Beagle - Magellan Water (BMW), Subantarctic Shelf Water (SSW) and Subantarctic Water (SAW). POC and PON decreased from maxima in BMW to intermediate values in SSW and minima in SAW. There was a highly significant correlation among POC, PON and fluorescence indicators of diagenetic maturity of dissolved humic matter. This, together with the inverse correlations of salinity with POC and PON, and the wide range of C:N ratios indicate that POM in the study area is partly derived from terrestrial runoff, superimposed by autochthonous components from plankton of different life stages. HB abundance was significantly correlated with POC and dissolved organic matter (DOM), likely reflecting a resource control of HB and a significant contribution of bacterial biomass to POM in the nanoparticle fraction. The direct relationship between HB and dissolved humics suggests bacterial uptake of DOM fractions otherwise considered refractory. POM complexity was reflected in a wide variation of δ13C, despite the narrow temperature range of this region. The variability of stable isotopes of POC could be accounted for by a model with a degree of detail hitherto not reported in the literature. A multiple regression including C:N ratio, ammonium and the quotient between log abundance of diatoms

  19. Characterization of Natural Organic Matter in Alluvial Aquifer Sediments: Approaches and Implications for Reactivity

    Science.gov (United States)

    Fox, P. M.; Nico, P. S.; Hao, Z.; Gilbert, B.; Tfaily, M. M.; Devadoss, J.

    2015-12-01

    Sediment-associated natural organic matter (NOM) is an extremely complex assemblage of organic molecules with a wide range of sizes, functional groups, and structures, which is intricately associated with mineral particles. The chemical nature of NOM may control its' reactivity towards metals, minerals, enzymes, and bacteria. Organic carbon concentrations in subsurface sediments are typically much lower than in surface soils, posing a distinct challenge for characterization. In this study, we investigated NOM associated with shallow alluvial aquifer sediments in a floodplain of the Colorado River. Total organic carbon (TOC) contents in these subsurface sediments are typically around 0.1%, but can range from 0.03% up to approximately 1.5%. Even at the typical TOC values of 0.1%, the mass of sediment-associated OC is approximately 5000 times higher than the mass of dissolved OC, representing a large pool of carbon that may potentially be mobilized or degraded under changing environmental conditions. Sediment-associated OC is much older than both the depositional age of the alluvial sediments and dissolved OC in the groundwater, indicating that the vast majority of NOM was sequestered by the sediment long before it was deposited in the floodplain. We have characterized the sediment-bound NOM from two locations within the floodplain with differing physical and geochemical properties. One location has relatively low organic carbon (mineral association across different biogeochemical regimes and assess the potential reactivity of various NOM pools.

  20. Comparative toxicity of ten organic chemicals to four earthworm species

    Energy Technology Data Exchange (ETDEWEB)

    Neuhauser, E.F.; Durkin, P.R.; Malecki, M.R.; Anatra, M.

    1986-01-01

    Ten organic chemicals were tested for toxicity to four earthworm species: Allolobophora tuberculata, Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus, using the European Economic Community's (EEC) earthworm artificial soil and contact testing procedure. The phenols were the most toxic chemicals tested, followed by the amine, substituted benzenes, halogenated aliphatic hydrocarbon, polycyclic aromatic hydrocarbon and phthalate as the least toxic chemical tested. Correlations among species within each type of test for a given chemical were extremely high, suggesting that the selection of earthworm test species does not markedly affect the assessment of a chemical's toxicity. The correlation between the two tests was low for all test species. The contact test LC50 for a given chemical cannot be directly correlated to an artificial soil test LC50 for the same earthworm species.

  1. Increased nitrogen availability counteracts climatic change feedback from increased temperature on boreal forest soil organic matter degradation

    Science.gov (United States)

    Erhagen, Bjorn; Nilsson, Mats; Oquist, Mats; Ilstedt, Ulrik; Sparrman, Tobias; Schleucher, Jurgen

    2014-05-01

    Over the last century, the greenhouse gas concentrations in the atmosphere have increased dramatically, greatly exceeding pre-industrial levels that had prevailed for the preceding 420 000 years. At the same time the annual anthropogenic contribution to the global terrestrial nitrogen cycle has increased and currently exceeds natural inputs. Both temperature and nitrogen levels have profound effects on the global carbon cycle including the rate of organic matter decomposition, which is the most important biogeochemical process that returns CO2 to the atmosphere. Here we show for the first time that increasing the availability of nitrogen not only directly affects the rate of organic matter decomposition but also significantly affects its temperature dependence. We incubated litter and soil organic matter from a long-term (40 years) nitrogen fertilization experiment in a boreal Scots pine (Pinus silvestris L.) forest at different temperatures and determined the temperature dependence of the decomposition of the sample's organic matter in each case. Nitrogen fertilization did not affect the temperature sensitivity (Q10) of the decomposition of fresh plant litter but strongly reduced that for humus soil organic matter. The Q10 response of the 0-3 cm soil layer decreased from 2.5±0.35 to an average of 1.9±0.21 over all nitrogen treatments, and from 2.2±0.19 to 1.6±0.16 in response to the most intense nitrogen fertilization treatment in the 4-7 cm soil layer. Long-term nitrogen additions also significantly affected the organic chemical composition (as determined by 13C CP-MAS NMR spectroscopy) of the soil organic matter. These changes in chemical composition contributed significantly (p<0.05) to the reduced Q10 response. These new insights into the relationship between nitrogen availability and the temperature sensitivity of organic matter decomposition will be important for understanding and predicting how increases in global temperature and rising anthropogenic

  2. The effect of gamma irradiation on the digestibility of organic matter of poultry excreta (In vitro)

    International Nuclear Information System (INIS)

    Al-Masri, M.R.

    1993-07-01

    The changes in the digestibility of dry matter and organic matter by enzyme (in vitro) for two types of the excreta of laying hens were studied. In type I, excreta were dried at 170-180 C for 10 minutes whereas in type II dried at 55-60 C for several days. Each type was divided into two parts, the first stored for 3 months with the control. The second part was irradiated by gamma irradiation at 100 KGy and stored for 3 months with the control. The results indicated that there was significant (0.05) difference in the digestibility of dry matter and organic matter and the percentage of crude fibre between samples and the control for the types I and II before and after storage. The dry matter digestibility for types I and II increased by 7%, and the organic matter digestibility increased by 17% for type I and by 11% for type II before and after storage. The increase in the digestibility of dry matter and organic matter is attributed to the decrease in crude fibre obtained by irradiation. The storage of excreta after drying has no effects on the rate of increase in the digestibility of dry matter and organic matter due to irradiation in both types (I and II). (author). 19 refs., 5 figs., 4 tabs

  3. Colored dissolved organic matter in shallow estuaries: the effect of source on quantification

    OpenAIRE

    W. K. Oestreich; N. K. Ganju; J. W. Pohlman; S. E. Suttles

    2015-01-01

    Light availability is of primary importance to the ecological function of shallow estuaries. For example, benthic primary production by submerged aquatic vegetation is contingent upon light penetration to the seabed. A major component that attenuates light in estuaries is colored dissolved organic matter (CDOM). CDOM is often measured via a proxy, fluorescing dissolved organic matter (fDOM...

  4. Processes controlling the production of aromatic water-soluble organic matter during litter decomposition

    NARCIS (Netherlands)

    Klotzbücher, T.; Kaiser, K.; Filley, T.R.; Kalbitz, K.

    2013-01-01

    Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a

  5. Bioavailability and export of dissolved organic matter from a tropical river during base- and stormflow conditions

    Science.gov (United States)

    Tracy N. Wiegner; Randee L. Tubal; Richard A. MacKenzie

    2009-01-01

    Concentrations, bioavailability, and export of dissolved organic matter (DOM), particulate organic matter (POM), and nutrients from the Wailuku River, Hawai'i, U.S.A., were examined under base- and stormflow conditions. During storms, DOM and POM concentrations increased approximately by factors of 2 and 11, respectively, whereas NO3...

  6. Differential recycling of coral and algal dissolved organic matter via the sponge loop

    NARCIS (Netherlands)

    Rix, L.; de Goeij, J.M.; van Oevelen, D.; Struck, U.; Al-Horani, F.A.; Wild, C.; Naumann, M.S.

    Corals and macroalgae release large quantities of dissolved organic matter (DOM), one of the largest sources of organic matter produced on coral reefs. By rapidly taking up DOM and transforming it into particulate detritus, coral reef sponges are proposed to play a key role in transferring the

  7. Organic Matter Decomposition following Harvesting and Site Preparation of a Forested Wetland

    Science.gov (United States)

    Carl C. Trettin; M. Davidian; M.F. Jurgensen; R. Lea

    1996-01-01

    Organic matter accumulation is an important process that affects ecosystem function in many northern wetlands. The cotton strip assay (CSA)was used to measure the effect of harvesting and two different site preparation treatments, bedding and trenching, on organic matter decomposition in a forested wetland. A Latin square experimental design was used to determine the...

  8. The role of aquatic fungi in transformations of organic matter mediated by nutrients

    Science.gov (United States)

    Cynthia J. Tant; Amy D. Rosemond; Andrew S. Mehring; Kevin A. Kuehn; John M. Davis

    2015-01-01

    1. We assessed the key role of aquatic fungi in modifying coarse particulate organic matter (CPOM) by affecting its breakdown rate, nutrient concentration and conversion to fine particulate organic matter (FPOM). Overall, we hypothesised that fungal-mediated conditioning and breakdown of CPOM would be accelerated when nutrient concentrations are increased and tested...

  9. Occurrence and abundance of carbohydrates and amino compounds in sequentially extracted labile soil organic matter fractions.

    Science.gov (United States)

    This study aimed to investigate the content of carbohydrates and amino compounds in three labile fraction of soil organic matter (SOM). Soil samples were collected from two agricultural fields in southern Italy and the light fraction (LF), the 500–53-µm particulate organic matter (POM) and the mobil...

  10. Organic matter distribution in the continental shelf sediments, off Kochi, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.

    (average 3.8%) than those towards Azhikode (average 1.97%). The sand predominant offshore relict sediments contain very low organic matter values (average 0.71%). The high organic matter content in the inner shelf is mainly controlled by the fine texture...

  11. Effect of selective removal of organic matter and iron oxides on the ...

    African Journals Online (AJOL)

    The effect of selective removal of organic matter and amorphous and crystalline iron oxides on N2-BET specific surface areas of some soil clays was evaluated. Clay fractions from 10 kaolinitic tropical soils were successively treated to remove organic matter by oxidation with Na hypochlorite, amorphous Fe oxide with acid ...

  12. Characteristics of dissolved organic matter following 20 years of peatland restoration

    NARCIS (Netherlands)

    Höll, B.S.; Fiedler, S.; Jungkunst, H.F.; Kalbitz, K.; Freibauer, A.; Drösler, M.; Stahr, K.

    2009-01-01

    The changes in the amounts and composition of dissolved organic matter (DOM) following long-term peat restoration are unknown, although this fraction of soil organic matter affects many processes in such ecosystems. We addressed this lack of knowledge by investigating a peatland in south-west

  13. Mean residence time of soil organic matter associated with kaolinite and smectite

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.; Plicht, van der J.; Wattel, J.T.; Breemen, van N.

    2003-01-01

    To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the C-14 activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in

  14. Mean residence time of soil organic matter associated with kaolinite and smectite

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.; Plicht, J. van der; Wattel, E.; Breemen, N. van

    To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the C-14 activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in

  15. FACTORS INFLUENCING PHOTOREACTIONS OF DISSOLVED ORGANIC MATTER IN A COASTAL RIVER OF THE SOUTHEASTERN UNITED STATES

    Science.gov (United States)

    Photoreactions of dissolved organic matter can affect the oxidizing capacity, nutrient dynamics, trace gas exchange, and color of surface waters. This study focuses on factors that affect the photoreactions of the colored dissolved organic matter (CDOM) in the Satilla River, a co...

  16. Urban infrastructure influences dissolved organic matter quality and bacterial metabolism in an urban stream network

    Science.gov (United States)

    Urban streams are degraded by a suite of factors, including burial beneath urban infrastructure (i.e., roads, parking lots) that eliminates light and reduces direct organic matter inputs to streams, with likely consequences for organic matter metabolism by microbes and carbon lim...

  17. Dependence of 210Po activity on organic matter in the reverine environs of coastal Kerala

    International Nuclear Information System (INIS)

    Narayana, Y.; Venunathan, N.

    2011-01-01

    This paper deals with the distribution of 210 Po in the river bank soil samples of three major rivers namely Bharathapuzha, Periyar and Kallada river of Kerala. The dependence of 210 Po activity on organic matter content in the samples was also studied. The soil samples were collected and analyzed for 210 Po radionuclide using standard radiochemical analytical method. Activity of 210 Po increases with increase in organic matter content in samples. Along the Bharathapuzha river bank the 210 Po activity ranges from 2.96 to 12.48 Bq kg -1 with mean 5.62 Bq kg -1 . The organic matter percentage in the samples ranges from 0.4 to 2.8 and a good correlation with correlation coefficient 0.9 was found between activity and organic matter percentage. In the Periyar river environs 210 Po activity ranges from 3.47 to 13.39 Bq kg -1 with mean value 9.27 Bq kg -1 . Organic matter percentage in these samples ranges from 1.20 to 4.10 and the correlation coefficient between 210 Po activity and organic matter percentage was found to be 0.8 In the Kallada river bank soil samples 210 Po activity ranges from 4.46 to 6.45 Bq kg -1 . The organic matter percentage ranges from 1.4 to 3. The correlation coefficient between 210 Po activity and organic matter percentage in the samples was found to be 0.9. (author)

  18. Soil Organic Matter and Soil Productivity: Searching for the Missing Link

    Science.gov (United States)

    Felipe G. Sanchez

    1998-01-01

    Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

  19. Stabilization of dissolved organic matter by aluminium: A toxic effect or stabilization through precipitation?

    NARCIS (Netherlands)

    Scheel, T.; Jansen, B.; van Wijk, A.J.; Verstraten, J.M.; Kalbitz, K.

    2008-01-01

    Carbon mineralization in acidic forest soils can be retarded by large concentrations of aluminium (Al). However, it is still unclear whether Al reduces C mineralization by direct toxicity to microorganisms or by decreased bioavailability of organic matter (OM) because dissolved organic matter (DOM)

  20. Impact of organic carbon and nutrients mobilized during chemical oxidation on subsequent bioremediation of a diesel-contaminated soil

    NARCIS (Netherlands)

    Sutton, N.B.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Remediation with in situ chemical oxidation (ISCO) impacts soil organic matter (SOM) and the microbial community, with deleterious effects on the latter being a major hurdle to coupling ISCO with in situ bioremediation (ISB). We investigate treatment of a diesel-contaminated soil with Fenton’s

  1. Cosorption study of organic pollutants and dissolved organic matter in a soil.

    Science.gov (United States)

    Flores-Céspedes, F; Fernández-Pérez, M; Villafranca-Sánchez, M; González-Pradas, E

    2006-08-01

    In this study we have evaluated the effects of dissolved organic matter (DOM) on sorption of imidacloprid, 3,4-dichloroaniline (3,4-DCA) and 4-bromoaniline (4-BA) on a typical calcareous soil (Luvic Xerosol) from south-eastern Spain. Two different types of DOM were used, that is to say, dissolved natural organic matter extracts from a commercial peat (DNOM) and a high-purity tannic acid (TA) solution. The experiments were carried out in a 0.01 M CaCl2 aqueous medium at 25 degrees C. The results indicated that the presence of both DNOM and TA, over a concentration range of 15-100 mg L(-1), produced an increase in the amount of 3,4-DCA and 4-BA sorbed and a decrease in the amount of imidacloprid retained on the soil studied. A modified distribution coefficient, K(doc), has been proposed as a safer parameter for soil sorption predictions of organic pollutants and it could be of help to model the fate of these in the environment.

  2. CQESTR Simulation of Soil Organic Matter Dynamics in Long-term Agricultural Experiments across USA

    Science.gov (United States)

    Gollany, H.; Liang, Y.; Albrecht, S.; Rickman, R.; Follett, R.; Wilhelm, W.; Novak, J.

    2009-04-01

    Soil organic matter (SOM) has important chemical (supplies nutrients, buffers and adsorbs harmful chemical compounds), biological (supports the growth of microorganisms and micro fauna), and physical (improves soil structure and soil tilth, stores water, and reduces surface crusting, water runoff) functions. The loss of 20 to 50% of soil organic carbon (SOC) from USA soils after converting native prairie or forest to production agriculture is well documented. Sustainable management practices for SOC is critical for maintaining soil productivity and responsible utilization of crop residues. As crop residues are targeted for additional uses (e.g., cellulosic ethanol feedstock) developing C models that predict change in SOM over time with change in management becomes increasingly important. CQESTR, pronounced "sequester," is a process-based C balance model that relates organic residue additions, crop management and soil tillage to SOM accretion or loss. The model works on daily time-steps and can perform long-term (100-year) simulations. Soil organic matter change is computed by maintaining a soil C budget for additions, such as crop residue or added amendments like manure, and organic C losses through microbial decomposition. Our objective was to simulate SOM changes in agricultural soils under a range of soil parent materials, climate and management systems using the CQESTR model. Long-term experiments (e.g. Champaign, IL, >100 yrs; Columbia, MO, >100 yrs; Lincoln, NE, 20 yrs) under various tillage practices, organic amendments, crop rotations, and crop residue removal treatments were selected for their documented history of the long-term effects of management practice on SOM dynamics. Simulated and observed values from the sites were significantly related (r2 = 94%, P management issue. CQESTR successfully simulated a substantial decline in SOM with 90% of crop residue removal for 50 years under various rotations at Columbia, MO and Champaign, IL. An increase in SOM

  3. Metal Speciation in Landfill Leachates with a Focus on the Influence of Organic Matter

    Energy Technology Data Exchange (ETDEWEB)

    F Claret; C Tournassat; C Crouzet; E Gaucher; T Schäfer; G Braibant; D Guyonnet

    2011-12-31

    This study characterizes the heavy-metal content in leachates collected from eight landfills in France. In order to identify heavy metal occurrence in the different size fractions of leachates, a cascade filtration protocol was applied directly in the field, under a nitrogen gas atmosphere to avoid metal oxidation. The results of analyses performed on the leachates suggest that most of the metals are concentrated in the <30 kDa fraction, while lead, copper and cadmium show an association with larger particles. Initial speciation calculations, without considering metal association with organic matter, suggest that leachate concentrations in lead, copper, nickel and zinc are super-saturated with respect to sulphur phases. Speciation calculations that account for metal complexation with organic matter, considered as fulvic acids based on C1(s) NEXAFS spectroscopy, show that this mechanism is not sufficient to explain such deviation from equilibrium conditions. It is therefore hypothesized that the deviation results also from the influence of biological activity on the kinetics of mineral phase precipitation and dissolution, thus providing a dynamic system. The results of chemical analyses of sampled fluids are compared with speciation calculations and some implications for the assessment of metal mobility and natural attenuation in a context of landfill risk assessment are discussed.

  4. Abatements of reduced sulphur compounds, colour, and organic matter from indigo dyeing effluents by electrocoagulation.

    Science.gov (United States)

    Tünay, Olcay; Simşeker, Merve; Kabdaşli, Isik; Olmez-Hanci, Tugba

    2014-08-01

    In the present study, the treatability of indigo dyeing effluents by the electrocoagulation (EC) process using stainless steel electrodes was experimentally investigated. The samples used were concentrated with main pollutant parameters of chemical oxygen demand (COD) (1000-1100 mg/L), reduced sulphur species (over 2000 mg SO2-(3)/L), and colour (0.12-0.13 1/cm). The study focused on the effect of main operation parameters on the EC process performance in terms of abatement of reduced sulphur compounds as well as decolourization and organic matter reduction. Results indicated that the performance of EC proved to be high providing total oxidation of the reduced sulphur compounds, almost complete decolourization, and COD removal up to 90%. Increasing applied current density from 22.5 to 45 mA/cm2 appreciably improved abatement of the reduced sulphur compounds for Sample I, but a further increase in the applied current density to 67.5 mA/cm2 did not accelerate the conversion rate to sulphate. The process performance was adversely affected by increasing initial concentration of the reduced sulphur compounds. Decolourization and organic matter removal efficiency enhanced with increasing applied current density. The main removal mechanism of the reduced sulphur compounds by EC was explained as conversion to sulphate via oxidation. Conversion rate to sulphate fitted pseudo-first-order kinetics very well.

  5. Soil texture analysis revisited: Removal of organic matter matters more than ever

    Science.gov (United States)

    Schjønning, Per; Watts, Christopher W.; Christensen, Bent T.; Munkholm, Lars J.

    2017-01-01

    Exact estimates of soil clay (<2 μm) and silt (2–20 μm) contents are crucial as these size fractions impact key soil functions, and as pedotransfer concepts based on clay and silt contents are becoming increasingly abundant. We examined the effect of removing soil organic matter (SOM) by H2O2 before soil dispersion and determination of clay and silt. Soil samples with gradients in SOM were retrieved from three long-term field experiments each with uniform soil mineralogy and texture. For soils with less than 2 g C 100 g-1 minerals, clay estimates were little affected by SOM. Above this threshold, underestimation of clay increased dramatically with increasing SOM content. Silt contents were systematically overestimated when SOM was not removed; no lower SOM threshold was found for silt, but the overestimation was more pronounced for finer textured soils. When exact estimates of soil particles <20 μm are needed, SOM should always be removed before soil dispersion. PMID:28542416

  6. Mobility of the dissolved organic matter through intact boom clay cores

    International Nuclear Information System (INIS)

    Put, M.J.; Dierckx, A.; Aertsens, M.; Canniere, P. de

    1998-01-01

    Performance assessment studies are expected to predict the enhancement of the migration of trivalent lanthanides and actinides due to their complexation with organic matter, which play a role as a transport agent [1]. Therefore, the mobility of the dissolved organic matter in the interstitial boom clay water is studied. For the first time, the mobile fraction present in the clay water is concentrated and labelled with a radioisotope to study the mobility of the organic matter in clay and the interaction of the mobile with the non-mobile. The isotopes tested as label are 125 I and 14 C. The 125 I label proved to be unstable and hence discarded. The labelled organic matter is then diluted for migration experiments on boom clay cores under anaerobic conditions. The influence of the molecular size on its mobility is studied by the separation of the labelled organic matter in different size fractions. (orig.)

  7. Evidence of micropore filling for sorption of nonpolar organic contaminants by condensed organic matter.

    Science.gov (United States)

    Ran, Yong; Yang, Yu; Xing, Baoshan; Pignatello, Joseph J; Kwon, Seokjoo; Su, Wei; Zhou, Li

    2013-01-01

    Although microporosity and surface area of natural organic matter (NOM) are crucial for mechanistic evaluation of the sorption process for nonpolar organic contaminants (NOCs), they have been underestimated by the N adsorption technique. We investigated the CO-derived internal hydrophobic microporosity () and specific surface area (SSA) obtained on dry samples and related them to sorption behaviors of NOCs in water for a wide range of condensed NOM samples. The is obtained from the total CO-derived microporosity by subtracting out the contribution of the outer surfaces of minerals and NOM using N adsorption-derived parameters. The correlation between or CO-SSA and fractional organic carbon content () is very significant, demonstrating that much of the microporosity is associated with internal NOM matrices. The average and CO-SSA are, respectively, 75.1 μL g organic carbon (OC) and 185 m g OC from the correlation analysis. The rigid aliphatic carbon significantly contributes to the microporosity of the Pahokee peat. A strong linear correlation is demonstrated between / and the OC-normalized sorption capacity at the liquid or subcooled liquid-state water solubility calculated via the Freundlich equation for each of four NOCs (phenanthrene, naphthalene, 1,3,5-trichlorobenzene, and 1,2-dichlorobenzene). We concluded that micropore filling ("adsorption") contributes to NOC sorption by condensed NOM, but the exact contribution requires knowing the relationship between the dry-state, CO-determined microporosity and the wet-state, NOC-available microporosity of the organic matter. The findings offer new clues for explaining the nonideal sorption behaviors of NOCs. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  8. ES1406 COST Action: Soil fauna: Key to Soil Organic Matter Dynamicsand Fertility. How far have we got?

    DEFF Research Database (Denmark)

    Jiménez, Juan; Filser, Juliane; Barot, Sébastien

    Soil organic matter (SOM) is key to soil fertility, climate change mitigation, combatting land degradation, and the conservation of above- and below-ground biodiversity and associated ecosystem services like decomposition, nutrient cycling, carbon sequestration, detoxification and maintenance...... of soil physico-chemical properties. SOM dynamics represent the balance between the input of plant material (residues, root-derived materials) and the output through decomposition (OM mineralization) by organisms, erosion and leaching. Approximately 20% of global CO2 emissions, one third of global CH4...... emissions and two thirds of N2O emissions originate from soils. In many soils, most of the macro-aggregate structure is formed by the activities of soil invertebrates and roots, with important consequences for soil organic matter dynamics, carbon sequestration and water infiltration at several spatial...

  9. Dynamics of dissolved organic matter in fjord ecosystems: Contributions of terrestrial dissolved organic matter in the deep layer

    Science.gov (United States)

    Yamashita, Youhei; McCallister, S. Leigh; Koch, Boris P.; Gonsior, Michael; Jaffé, Rudolf

    2015-06-01

    Annually, rivers and inland water systems deliver a significant amount of terrestrial organic matter (OM) to the adjacent coastal ocean in both particulate and dissolved forms; however, the metabolic and biogeochemical transformations of OM during its seaward transport remains one of the least understood components of the global carbon cycle. This transfer of terrestrial carbon to marine ecosystems is crucial in maintaining trophic dynamics in coastal areas and critical in global carbon cycling. Although coastal regions have been proposed as important sinks for exported terrestrial materials, most of the global carbon cycling data, have not included fjords in their budgets. Here we present distributional patterns on the quantity and quality of dissolved OM in Fiordland National Park, New Zealand. Specifically, we describe carbon dynamics under diverse environmental settings based on dissolved organic carbon (DOC) depth profiles, oxygen concentrations, optical properties (fluorescence) and stable carbon isotopes. We illustrate a distinct change in the character of DOC in deep waters compared to surface and mid-depth waters. Our results suggest that, both, microbial reworking of terrestrially derived plant detritus and subsequent desorption of DOC from its particulate counterpart (as verified in a desorption experiment) are the main sources of the humic-like enriched DOC in the deep basins of the studied fjords. While it has been suggested that short transit times and protection of OM by mineral sorption may ultimately result in significant terrestrial carbon burial and preservation in fjords, our data suggests the existence of an additional source of terrestrial OM in the form of DOC generated in deep, fjord water.

  10. Sulfurization of Dissolved Organic Matter Increases Hg-Sulfide-Dissolved Organic Matter Bioavailability to a Hg-Methylating Bacterium.

    Science.gov (United States)

    Graham, Andrew M; Cameron-Burr, Keaton T; Hajic, Hayley A; Lee, Connie; Msekela, Deborah; Gilmour, Cynthia C

    2017-08-15

    Reactions of dissolved organic matter (DOM) with aqueous sulfide (termed sulfurization) in anoxic environments can substantially increase DOM's reduced sulfur functional group content. Sulfurization may affect DOM-trace metal interactions, including complexation and metal-containing particle precipitation, aggregation, and dissolution. Using a diverse suite of DOM samples, we found that susceptibility to additional sulfur incorporation via reaction with aqueous sulfide increased with increasing DOM aromatic-, carbonyl-, and carboxyl-C content. The role of DOM sulfurization in enhancing Hg bioavailability for microbial methylation was evaluated under conditions typical of Hg methylation environments (μM sulfide concentrations and low Hg-to-DOM molar ratios). Under the conditions of predicted metacinnabar supersaturation, microbial Hg methylation increased with increasing DOM sulfurization, likely reflecting either effective inhibition of metacinnabar growth and aggregation or the formation of Hg(II)-DOM thiol complexes with high bioavailability. Remarkably, Hg methylation efficiencies with the most sulfurized DOM samples were similar (>85% of total Hg methylated) to that observed in the presence of l-cysteine, a ligand facilitating rapid Hg(II) biouptake and methylation. This suggests that complexes of Hg(II) with DOM thiols have similar bioavailability to Hg(II) complexes with low-molecular-weight thiols. Overall, our results are a demonstration of the importance of DOM sulfurization to trace metal and metalloid (especially mercury) fate in the environment. DOM sulfurization likely represents another link between anthropogenic sulfate enrichment and MeHg production in the environment.

  11. Evolution of organic matter during composting of different organic wastes assessed by CPMAS 13C NMR spectroscopy

    International Nuclear Information System (INIS)

    Caricasole, P.; Provenzano, M.R.; Hatcher, P.G.; Senesi, N.

    2011-01-01

    In this paper, the evolution of organic matter (OM) during composting of different mixtures of various organic wastes was assessed by means of chemical analyses and CPMAS 13 C NMR spectroscopy measured during composting. The trends of temperatures and C/N ratios supported the correct evolution of the processes. The CPMAS 13 C NMR spectra of all composting substrates indicated a reduction in carbohydrates and an increase in aromatic, phenolic, carboxylic and carbonylic C which suggested a preference by microorganisms for easily degradable C molecules. The presence of hardly degradable pine needles in one of the substrates accounted for the lowest increase in alkyl C and the lowest reduction in carbohydrates and carboxyl C as opposite to another substrate characterized by the presence of a highly degradable material such as spent yeast from beer production, which showed the highest increase of the alkyl C/O-alkyl C ratio. The highest increase of COOH deriving by the oxidative degradation of cellulose was shown by a substrate composed by about 50% of plant residues. The smallest increases in alkyl C/O-alkyl C ratio and in polysaccharides were associated to the degradation of proteins and lipids which are major components of sewage sludge. Results obtained were related to the different composition of fresh organic substrates and provided evidence of different OM evolution patterns as a function of the initial substrate composition.

  12. Fluorescence quantum yields of natural organic matter and organic compounds: Implications for the fluorescence-based interpretation of organic matter composition

    DEFF Research Database (Denmark)

    Wünsch, Urban; Murphy, Kathleen R.; Stedmon, Colin

    2015-01-01

    to more than 200 modeled spectra (PARAFAC components) in the OpenFluor database. Apparent matches, based on spectral similarity, were subsequently evaluated using molar fluorescence and absorbance. Five organic compounds were potential matches with PARAFAC components from 16 studies; however, the ability......Absorbance and fluorescence spectroscopy are economical tools for tracing the supply, turnover and fate of dissolved organic matter (DOM). The colored and fluorescent fractions of DOM (CDOM and FDOM, respectively) are linked by the apparent fluorescence quantum yield (AQY) of DOM, which reflects...... the likelihood that chromophores emit fluorescence after absorbing light. Compared to the number of studies investigating CDOM and FDOM, few studies have systematically investigated AQY spectra for DOM, and linked them to fluorescence quantum yields (Φ) of organic compounds. To offer a standardized approach...

  13. Transport of organic contaminants in subsoil horizons and effects of dissolved organic matter related to organic waste recycling practices.

    Science.gov (United States)

    Chabauty, Florian; Pot, Valérie; Bourdat-Deschamps, Marjolaine; Bernet, Nathalie; Labat, Christophe; Benoit, Pierre

    2016-04-01

    Compost amendment on agricultural soil is a current practice to compensate the loss of organic matter. As a consequence, dissolved organic carbon concentration in soil leachates can be increased and potentially modify the transport of other solutes. This study aims to characterize the processes controlling the mobility of dissolved organic matter (DOM) in deep soil layers and their potential impacts on the leaching of organic contaminants (pesticides and pharmaceutical compounds) potentially present in cultivated soils receiving organic waste composts. We sampled undisturbed soil cores in the illuviated horizon (60-90 cm depth) of an Albeluvisol. Percolation experiments were made in presence and absence of DOM with two different pesticides, isoproturon and epoxiconazole, and two pharmaceutical compounds, ibuprofen and sulfamethoxazole. Two types of DOM were extracted from two different soil surface horizons: one sampled in a plot receiving a co-compost of green wastes and sewage sludge applied once every 2 years since 1998 and one sampled in an unamended plot. Results show that DOM behaved as a highly reactive solute, which was continuously generated within the soil columns during flow and increased after flow interruption. DOM significantly increased the mobility of bromide and all pollutants, but the effects differed according the hydrophobic and the ionic character of the molecules. However, no clear effects of the origin of DOM on the mobility of the different contaminants were observed.

  14. Transport and Fate of Volatile Organic Chemical in Soils

    DEFF Research Database (Denmark)

    Petersen, Lis Wollesen

    Recently much attention has been paid to the behavior of volatile organic chemicals (VOCs) in the environment. This is due to the fact that the environmental pollution with these hazardous chemicals has drastically increased during the last decades. The present study is limited to consider...... the transport and fate of VOCs in the gaseous phase, thus contributing to the overall understanding of VOCs behavior in soil, which eventually will facilitate future cleanup....

  15. Liming effects on the chemical composition of the organic surface layer of a mature Norway spruce stand (Picea abies [L.] Karst.)

    NARCIS (Netherlands)

    Rosenberg, W.; Nierop, K.G.J.; Knicker, H.; Jager, de P.A.; Kreutzer, K.; Weiá, T.

    2003-01-01

    The application of lime in a mature Norway spruce (Picea abies [L.] Karst.) forest in southern Germany induced major changes in the activity of soil organisms and root growth. Since this may influence the chemical compostion of the soil organic matter (SOM) of the organic surface layer, its

  16. Note on the chemical potential of decoupled matter in the Universe

    NARCIS (Netherlands)

    Nieuwenhuizen, T.M.; Pombo, C.

    2011-01-01

    Textbooks on cosmology exhibit a thermodynamic inconsistency for free streaming, decoupled matter. It is connected here to the chemical potential, which deviates from its equilibrium value μ = @kBT , where @ is the usual parameter of the Fermi-Dirac or Bose-Einstein distribution function.

  17. Controls of dissolved organic matter quality: Evidence from a large-scale boreal lake survey

    DEFF Research Database (Denmark)

    Kothawala, D.N.; Stedmon, Colin; Müller, R.A.

    2014-01-01

    Inland waters transport large amounts of dissolved organic matter (DOM) from terrestrial environments to the oceans, but DOM also reacts en route, with substantial water column losses by mineralization and sedimentation. For DOM transformations along the aquatic continuum, lakes play an important...... role as they retain waters in the landscape allowing for more time to alter DOM. We know DOM losses are significant at the global scale, yet little is known about how the reactivity of DOM varies across landscapes and climates. DOM reactivity is inherently linked to its chemical composition. We used...... analyzed in relation to lake chemistry, catchment, and climate characteristics. Land cover, particularly the percentage of water in the catchment, was a primary factor explaining variability in PARAFAC components. Likewise, lake water retention time influenced DOM quality. These results suggest...

  18. Microbial Electrolysis Cells for High Yield Hydrogen Gas Production from Organic Matter

    KAUST Repository

    Logan, Bruce E.

    2008-12-01

    The use of electrochemically active bacteria to break down organic matter, combined with the addition of a small voltage (>0.2 V in practice) in specially designed microbial electrolysis cells (MECs), can result in a high yield of hydrogen gas. While microbial electrolysis was invented only a few years ago, rapid developments have led to hydrogen yields approaching 100%, energy yields based on electrical energy input many times greater than that possible by water electrolysis, and increased gas production rates. MECs used to make hydrogen gas are similar in design to microbial fuel cells (MFCs) that produce electricity, but there are important differences in architecture and analytical methods used to evaluate performance. We review here the materials, architectures, performance, and energy efficiencies of these MEC systems that show promise as a method for renewable and sustainable energy production, and wastewater treatment. © 2008 American Chemical Society.

  19. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    Science.gov (United States)

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-01

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  20. Characterization of organic matter in lake sediments from Minnesota and Yellowstone National Park

    Science.gov (United States)

    Dean, Walter E.

    2006-01-01

    Samples of sediment from lakes in Minnesota and Yellowstone National Park (YNP) were analyzed for organic carbon (OC), hydrogen richness by Rock-Eval pyrolysis, and stable carbon- and nitrogen-isotope composition of bulk organic matter. Values of delta 13C of lake plankton tend to be around -28 to -32 parts per thousand (0/00). Organic matter with values of delta 13C in the high negative 20s overlap with those of organic matter derived from C3 higher terrestrial plants but are at least 10 0/00 more depleted in 13C than organic matter derived from C4 terrestrial plants. If the organic matter is produced mainly by photosynthetic plankton and is not oxidized in the water column, there may be a negative correlation between H-richness (Rock-Eval pyrolysis H-index) and delta 13C, with more H-rich, algal organic matter having lower values of delta 13C. However, if aquatic organic matter is oxidized in the water column, or if the organic matter is a mixture of terrestrial and aquatic organic matter, then there may be no correlation between H-richness and carbon-isotopic composition. Values of delta 13C lower than about -28 0/00 probably indicate a contribution of bacterial biomass produced in the hypolimnion by chemoautotrophy or methanotrophy. In highly eutrophic lakes in which large amounts of 13C-depleted organic matter is continually removed from the epilimnion by photosynthesis throughout the growing season, the entire carbon reservoir in the epilimnion may become severely 13C-enriched so that 13C-enriched photosynthetic organic matter may overprint 13C-depleted chemosynthetic bacterial organic matter produced in the hypolimnon. Most processes involved with the nitrogen cycle in lakes, such as production of ammonia and nitrate, tend to produce 15N-enriched values of delta 15N. Most Minnesota lake sediments are 15N-enriched. However, some of the more OC-rich sediments have delta 15N values close to zero (delta 15N of air), suggesting that organic matter production is

  1. Colored dissolved organic matter in Tampa Bay, Florida

    Science.gov (United States)

    Chen, Z.; Hu, C.; Conmy, R.N.; Muller-Karger, F.; Swarzenski, P.

    2007-01-01

    Absorption and fluorescence of colored dissolved organic matter (CDOM) and concentrations of dissolved organic carbon (DOC), chlorophyll and total suspended solids in Tampa Bay and its adjacent rivers were examined in June and October of 2004. Except in Old Tampa Bay (OTB), the spatial distribution of CDOM showed a conservative relationship with salinity in June, 2004 (aCDOM(400) = − 0.19 × salinity + 6.78, R2 = 0.98, n = 17, salinity range = 1.1–32.5) with little variations in absorption spectral slope and fluorescence efficiency. This indicates that CDOM distribution was dominated by mixing. In October, 2004, CDOM distribution was nonconservative with an average absorption coefficient (aCDOM(400), ∼ 7.76 m-1) about seven times higher than that in June (∼ 1.11 m-1). The nonconservative behavior was caused largely by CDOM removal at intermediate salinities (e.g., aCDOM(400) removal > 15% at salinity ∼ 13.0), which likely resulted from photobleaching due to stronger stratification. The spatial and seasonal distributions of CDOM in Tampa Bay showed that the two largest rivers, the Alafia River (AR) and Hillsborough River (HR) were dominant CDOM sources to most of the bay. In OTB, however, CDOM showed distinctive differences: lower absorption coefficient, higher absorption spectral slopes, and lower ratios of CDOM absorption to DOC and higher fluorescence efficiency. These differences may have stemmed from (1) changes in CDOM composition by more intensive photobleaching due to the longer residence time of water mass in OTB; (2) other sources of CDOM than the HR/AR inputs, such as local creeks, streams, groundwater, and/or bottom re-suspension. Average CDOM absorption in Tampa Bay at 443 nm, aCDOM(443), was about five times higher in June and about ten times higher in October than phytoplankton pigment absorption, aph(443), indicating that blue light attenuation in the water column was dominated by CDOM rather than by phytoplankton absorption throughout the

  2. Effects of exotic plantation forests on soil edaphon and organic matter fractions.

    Science.gov (United States)

    Xu, Gang; Liu, Yao; Long, Zhijian; Hu, Shanglian; Zhang, Yuanbin; Jiang, Hao

    2018-06-01

    There is uncertainty and limited knowledge regarding soil microbial properties and organic matter fractions of natural secondary forest accompanying chemical environmental changes of replacement by pure alien plantation forests in a hilly area of southwest of Sichuan province China. The aim of this study was to evaluate the impact of natural secondary forest (NSF) to pure Cryptomeria fortunei forest (CFF) and Cunninghamia lanceolata forest (CLF) on soil organic fractions and microbial communities. The results showed that the soil total phospholipid fatty acids (PLFAs), total bacteria and fungi, microbial carbon pool, organic recalcitrant carbon (C) and (N) fractions, soil microbial quotient and labile and recalcitrant C use efficiencies in each pure plantation were significantly decreased, but their microbial N pool, labile C and N pools, soil carbon dioxide efflux, soil respiratory quotient and recalcitrant N use efficiency were increased. An RDA analysis revealed that soil total PLFAs, total bacteria and fungi and total Gram-positive and Gram-negative bacteria were significantly associated with exchangeable Al 3+ , exchangeable acid, Al 3+ , available P and Mg 2+ and pH, which resulted into microbial functional changes of soil labile and recalcitrant substrate use efficiencies. Modified microbial C- and N-use efficiency due to forest conversion ultimately meets those of rapidly growing trees in plantation forests. Enlarged soil labile fractions and soil respiratory quotients in plantation forests would be a potential positive effect for C source in the future forest management. Altogether, pure plantation practices could provoke regulatory networks and functions of soil microbes and enzyme activities, consequently leading to differentiated utilization of soil organic matter fractions accompanying the change in environmental factors. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Influencing factors on δ(13C) of organic matter and carbonate in labke sediments on songnen plain

    International Nuclear Information System (INIS)

    Ou Wenjia; Zhang Chengjun

    2009-01-01

    Carbon isotopic compositions of organic matter and carbonate in surface sediments from lakes in Songnen Plain, northeast of China, were carried out.n-alkanes carbon distribution characteristics of the organic matter in lake sediments were also analyzed to identify the source of organic matter and sedimentary environment in these lakes. With the limnological characteristics of water and sediment, the influencing factors on isotopic composition in sedimentary organic matter and carbonate were discussed. The results showed that types of organic matter affected the carbon isotopic composition. 13 C of carbonate depleted by input of biologic organic matter and enriched by input of oil pollution. (authors)

  4. Poisoning of bubble propelled catalytic micromotors: the chemical environment matters.

    Science.gov (United States)

    Zhao, Guanjia; Sanchez, Samuel; Schmidt, Oliver G; Pumera, Martin

    2013-04-07

    Self-propelled catalytic microjets have attracted considerable attention in recent years and these devices have exhibited the ability to move in complex media. The mechanism of propulsion is via the Pt catalysed decomposition of H2O2 and it is understood that the Pt surface is highly susceptible to poisoning by sulphur-containing molecules. Here, we show that important extracellular thiols as well as basic organic molecules can significantly hamper the motion of catalytic microjet engines. This is due to two different mechanisms: (i) molecules such as dimethyl sulfoxide can quench the hydroxyl radicals produced at Pt surfaces and reduce the amount of oxygen gas generated and (ii) molecules containing -SH, -SSR, and -SCH3 moieties can poison the catalytically active platinum surface, inhibiting the motion of the jet engines. It is essential that the presence of such molecules in the environment be taken into consideration for future design and operation of catalytic microjet engines. We show this effect on catalytic micromotors prepared by both rolled-up and electrodeposition approaches, demonstrating that such poisoning is universal for Pt catalyzed micromotors. We believe that our findings will contribute significantly to this field to develop alternative systems or catalysts for self-propulsion when practical applications in the real environment are considered.

  5. Chemical equilibrium modeling of organic acids, pH, aluminum, and iron in Swedish surface waters.

    Science.gov (United States)

    Sjöstedt, Carin S; Gustafsson, Jon Petter; Köhler, Stephan J

    2010-11-15

    A consistent chemical equilibrium model that calculates pH from charge balance constraints and aluminum and iron speciation in the presence of natural organic matter is presented. The model requires input data for total aluminum, iron, organic carbon, fluoride, sulfate, and charge balance ANC. The model is calibrated to pH measurements (n = 322) by adjusting the fraction of active organic matter only, which results in an error of pH prediction on average below 0.2 pH units. The small systematic discrepancy between the analytical results for the monomeric aluminum fractionation and the model results is corrected for separately for two different fractionation techniques (n = 499) and validated on a large number (n = 3419) of geographically widely spread samples all over Sweden. The resulting average error for inorganic monomeric aluminum is around 1 µM. In its present form the model is the first internally consistent modeling approach for Sweden and may now be used as a tool for environmental quality management. Soil gibbsite with a log *Ks of 8.29 at 25°C together with a pH dependent loading function that uses molar Al/C ratios describes the amount of aluminum in solution in the presence of organic matter if the pH is roughly above 6.0.

  6. Source and Processes of Dissolved Organic Matter in a Bangladesh Groundwater

    Science.gov (United States)

    McKnight, D. M.; Simone, B. E.; Mladenov, N.; Zheng, Y.; Legg, T. M.; Nemergut, D.

    2010-12-01

    Arsenic contamination of groundwater is a global health crisis, especially in Bangladesh where an estimated 40 million people are at risk. The release of geogenic arsenic bound to sediments into groundwater is thought to be influenced by dissolved organic matter (DOM) through several biogeochemical processes. Abiotically, DOM can promote the release of sediment bound As through the formation of DOM-As complexes and competitive interactions between As and DOM for sorption sites on the sediment. Additionally, the labile portion of groundwater DOM can serve as an electron donor to support microbial growth and the more recalcitrant humic DOM may serve as an electron shuttle, facilitating the eventual reduction of ferric iron present as iron oxides in sediments and consequently the mobilization of sorbed As and organic material. The goal of this study is to understand the source of DOM in representative Bangladesh groundwaters and the DOM sorption processes that occur at depth. We report chemical characteristics of representative DOM from a surface water, a shallow low-As groundwater, mid-depth high-As groundwater from the Araihazar region of Bangladesh. The humic DOM from groundwater displayed a more terrestrial chemical signature, indicative of being derived from plant and soil precursor materials, while the surface water humic DOM had a more microbial signature, suggesting an anthropogenic influence. In terms of biogeochemical processes occurring in the groundwater system, there is evidence from a diverse set of chemical characteristics, ranging from 13C-NMR spectroscopy to the analysis of lignin phenols, for preferential sorption onto iron oxides influencing the chemistry and reactivity of humic DOM in high As groundwater in Bangladesh. Taken together, these results provide chemical evidence for anthropogenic influence and the importance of sorption reactions at depth controlling the water quality of high As groundwater in Bangladesh.

  7. A Robust Analysis Method For Δ13c Signal Of Bulk Organic Matter In Speleothems

    Science.gov (United States)

    Bian, F.; Blyth, A. J.; Smith, C.; Baker, A.

    2017-12-01

    Speleothems preserve organic matter that is derived from both the surface soil and cave environments. This organic matter can be used to understand paleoclimate and paleoenvironments. However, a stable and quick micro-analysis method to measure the δ13C signals from speleothem organic matter separate from the total δ13C remains absent. And speleothem organic geochemistry is still relatively unexplored compared to inorganic geochemistry. In this research, for the organic matter analysis, bulk homogeneous power samples were obtained from one large stalagmite. These were dissolved by phosphoric acid to produce the aqueous solution. Then, the processed solution was degassed through a rotational vacuum concentrator. A liquid chromatograph was coupled to IRMS to control the oxidization and the measurement of analytes. This method is demonstrated to be robust for the analysis of speleothem d13C organic matter analysis under different preparation and instrumental settings, with the low standard deviation ( 0.2‰), and low sample consumption (<25 mg). Considering the complexity of cave environments, this method will be useful in further investigations the δ13C of entrapped organic matter and environmental controls in other climatic and ecological contexts, including the determination of whether vegetation or soil microbial activity is the dominant control on speleothem d13C of organic matter.

  8. Redox chemistry and natural organic matter (NOM): Geochemists' dream, analytical chemists' nightmare

    Science.gov (United States)

    Macalady, Donald L.; Walton-Day, Katherine

    2011-01-01

    Natural organic matter (NOM) is an inherently complex mixture of polyfunctional organic molecules. Because of their universality and chemical reversibility, oxidation/reductions (redox) reactions of NOM have an especially interesting and important role in geochemistry. Variabilities in NOM composition and chemistry make studies of its redox chemistry particularly challenging, and details of NOM-mediated redox reactions are only partially understood. This is in large part due to the analytical difficulties associated with NOM characterization and the wide range of reagents and experimental systems used to study NOM redox reactions. This chapter provides a summary of the ongoing efforts to provide a coherent comprehension of aqueous redox chemistry involving NOM and of techniques for chemical characterization of NOM. It also describes some attempts to confirm the roles of different structural moieties in redox reactions. In addition, we discuss some of the operational parameters used to describe NOM redox capacities and redox states, and describe nomenclature of NOM redox chemistry. Several relatively facile experimental methods applicable to predictions of the NOM redox activity and redox states of NOM samples are discussed, with special attention to the proposed use of fluorescence spectroscopy to predict relevant redox characteristics of NOM samples.

  9. Fixation and reduction of uranium by natural organic matter: reaction mechanisms and kinetics

    International Nuclear Information System (INIS)

    Nakashima, S.; Perruchot, A.; Trichet, J.; Disnar, J.R.

    1987-01-01

    The reactivity of lignite towards soluble uranyl species in an aqueous medium is experimentally investigated as a function of temperature (between 20 0 C and 400 0 C). The fixation process starts near 45 0 C, with reduction beginning around 120 0 C. The fixation process leads to the formation of chemically and thermally stable organo-uranyl species. The reduction of free uranyl species is accompanied by a stoichiometric (2:1) liberation of protons into the medium. These protons originate from the organic matter which thus undergoes dehydrogenation. The general evolution of the carbonaceous residue in the course of this reaction shows that alcoholic and aliphatic hydrocarbon groups are responsible for the reduction. This chemical dehydrogenation could explain the low hydrogen content of natural organic materials associated with uraniferous deposits. The kinetics of the reduction step have been studied at 180 0 C, 190 0 C and 200 0 C. The kinetic parameters determined over this temperature range, and the extrapolation made to 20 0 C, show that reduction can be a crucial process in the geochemical behaviour of uranium especially in the thermal conditions in which sedimentary basins evolve [fr

  10. Composition and structure of natural organic matter through advanced nuclear magnetic resonance techniques

    Directory of Open Access Journals (Sweden)

    Dainan Zhang

    2017-02-01

    Full Text Available Abstract Natural organic matter (NOM plays important roles in biological, chemical, and physical processes within the terrestrial and aquatic ecosystem. Despite its importance, a clear and exhaustive knowledge on NOM chemistry still lacks. Aiming to prove that advanced solid-state 13C nuclear magnetic resonance (NMR techniques may contribute to fill such a gap, in this paper we reported relevant examples of its applicability to NOM components, such as biomass, deposition material, sediments, and kerogen samples. It is found that nonhydrolyzable organic carbons (NHC, chars, and polymethylene carbons are important in the investigated samples. The structure of each of the NHC fractions is similar to that of kerogens, highlighting the importance of selective preservation of NOM to the kerogen origin in the investigated aquatic ecosystems. Moreover, during the artificial maturation experiments of kerogen, the chemical and structural characteristics such as protonated aromatic, nonprotonated carbons, and aromatic cluster size play important roles in the origin and variation of nanoporosity during kerogen maturation. Graphical abstract NMR parameters of thermally stimulated kerogens

  11. Variabilidade espacial de atributos químicos do solo sob cafeeiro Conilon: relação com textura, matéria orgânica e relevo Spatial variability of soil chemical attributes in Conilon coffee plantation: relationships with soil texture, organic matter and relief

    Directory of Open Access Journals (Sweden)

    Diego Lang Burak

    2012-01-01

    Principal Component Analysis (PCA were used to describe the influence of topography. Spatial variability was more influenced by topography at lower depths. The PCA technique showed that attributes associated with soil reactions (pH, Ca, Mg, Al, V and m contributed to the first principal component (PC1 at the two studied depths. Only PC1 at the 0.0 - 0.1 m depth was, however, correlated to topography; higher altitudes and smaller slopes favored higher clay content and lower coarse sand proportion, thus resulting in increased retention of cations in the soil. The humic substances of organic matter have low influence on the variability of the chemical attributes, with the exception of Ca and Mg that are well related to humic acids in sites that are richer in sand. Homogeneous areas correlated with geomorphologic attributes was been describe for the K concentrations compared to other attributes at both depths. Thus, the use of spatial analysis for landscape stratification in homogeneous regions for the purpose of fertilizer management depends not only on topography, but on the chemical attributes evaluated and on sample depth.

  12. Preservation of labile organic matter in soils of drained thaw lakes in Northern Alaska

    Science.gov (United States)

    Mueller, Carsten W.; Rethemeyer, Janet; Kao-Kniffin, Jenny; Löppmann, Sebastian; Hinkel, Kenneth; Bockheim, James

    2014-05-01

    A large number of studies predict changing organic matter (OM) dynamics in arctic soils due to global warming. In contrast to rather slowly altering bulk soil properties, single soil organic matter (SOM) fractions can provide a more detailed picture of the dynamics of differently preserved SOM pools in climate sensitive arctic regions. By the study of the chemical composition of such distinctive SOM fractions using nuclear magnetic resonance spectroscopy (NMR) together with radiocarbon analyses it is possible to evaluate the stability of the major OM pools. Approximately 50-75% of Alaska's Arctic Coastal Plain is covered with thaw lakes and drained thaw lakes that follow a 5,000 yr cycle of development (between creation and final drainage), thus forming a natural soil chronosequence. The drained thaw lakes offer the possibility to study SOM dynamics affected by permafrost processes over millennial timescales. In April 2010 we sampled 16 soil cores (including the active and permanent layer) reaching from young drained lakes (0-50 years since drainage) to ancient drained lakes (3000-5500 years since drainage). Air dried soil samples from soil horizons of the active and permanent layer were subjected to density fractionation in order to differentiate particulate OM and mineral associated OM. The chemical composition of the SOM fractions was analyzed by 13C CPMAS NMR spectroscopy. For a soil core of a young and an ancient drained thaw lake basin we also analyzed the 14C content. For the studied soils we can show that up to over 25 kg OC per square meter are stored mostly as labile, easily degradable organic matter rich in carbohydrates. In contrast only 10 kg OC per square meter were sequestered as presumably more stable mineral associated OC dominated by aliphatic compounds. Comparable to soils of temperate regions, we found small POM (dating we could show the stabilization of younger more labile OM at greater depth in buried O horizons. Additionally the study of the

  13. Organic matter in primitive meteorites: a study of the hydrogen isotopic distribution in CM-type carbonaceous chondrites

    Science.gov (United States)

    Piani, L.; Yurimoto, H.; Remusat, L.; Gonzales, A.; Marty, B.

    2017-12-01

    Chondrite meteorites are fragments of rocks coming from small bodies of the asteroid belt and constitute witnesses of the volatile-rich reservoirs present in the inner protoplanetary disk. Among these meteorites, carbonaceous chondrites contain the largest quantity of water and organic matter and are one of the most probable candidates for the delivery of water and molecular origin of life to Earth. Organic matter in carbonaceous chondrites is intimately mixed with hydrated minerals challenging its in situ characterization and the determination of its H-isotope composition (Le Guillou et al., GCA 131, 2014). Organic matter occurs as soluble components (in water or organic solvents) and an insoluble macromolecule. The insoluble organic matter (IOM) is efficiently isolated after acid leaching of the chondrite minerals. IOM has thus been investigated by a large set of analytical techniques allowing its structural organization, chemical composition and isotopic composition to be determined at several scales (e.g. Derenne and Robert, MAPS 45, 2010). In the soluble counterpart (SOM), targeted studies have shown large ranges of D/H ratios in the different classes of soluble organic compounds (i.e. carboxylic acids, ketones and aldehydes, amino-acids etc.) (Remusat, Planetary Mineralogy 15, 2015 and references therein). This D/H distribution indicates a complex and probably multiple-stage synthesis of this organic compounds occurring at different stages of the disk evolution. Nevertheless, inventories of the known C-bearing species in carbonaceous chondrites (carbonates, SOM and IOM) show that about 40-50 % of the carbon is hidden within the matrix (Alexander et al., MAPS 50, 2015). In this study, we perform in situ hydrogen isotope analyses at the micrometer scale by secondary ion mass spectrometry to investigate the distribution of organic matter in primitive chondrites without the use of any chemical treatment. Correlated analyses of the D/H and C/H ratios allow us to

  14. Transformation of soil organic matter in a Japanese larch forest. Radiocarbon and stable carbon isotope compositions versus soil depth

    International Nuclear Information System (INIS)

    Liu Wei; Moriizumi, J