WorldWideScience

Sample records for carbonate phosphate organic

  1. Quantum mechanical calculation of aqueuous uranium complexes: carbonate, phosphate, organic and biomolecular species

    Directory of Open Access Journals (Sweden)

    Jha Prashant

    2009-08-01

    Full Text Available Abstract Background Quantum mechanical calculations were performed on a variety of uranium species representing U(VI, U(V, U(IV, U-carbonates, U-phosphates, U-oxalates, U-catecholates, U-phosphodiesters, U-phosphorylated N-acetyl-glucosamine (NAG, and U-2-Keto-3-doxyoctanoate (KDO with explicit solvation by H2O molecules. These models represent major U species in natural waters and complexes on bacterial surfaces. The model results are compared to observed EXAFS, IR, Raman and NMR spectra. Results Agreement between experiment and theory is acceptable in most cases, and the reasons for discrepancies are discussed. Calculated Gibbs free energies are used to constrain which configurations are most likely to be stable under circumneutral pH conditions. Reduction of U(VI to U(IV is examined for the U-carbonate and U-catechol complexes. Conclusion Results on the potential energy differences between U(V- and U(IV-carbonate complexes suggest that the cause of slower disproportionation in this system is electrostatic repulsion between UO2 [CO3]35- ions that must approach one another to form U(VI and U(IV rather than a change in thermodynamic stability. Calculations on U-catechol species are consistent with the observation that UO22+ can oxidize catechol and form quinone-like species. In addition, outer-sphere complexation is predicted to be the most stable for U-catechol interactions based on calculated energies and comparison to 13C NMR spectra. Outer-sphere complexes (i.e., ion pairs bridged by water molecules are predicted to be comparable in Gibbs free energy to inner-sphere complexes for a model carboxylic acid. Complexation of uranyl to phosphorus-containing groups in extracellular polymeric substances is predicted to favor phosphonate groups, such as that found in phosphorylated NAG, rather than phosphodiesters, such as those in nucleic acids.

  2. Removal of organic wastes containing tributyl phosphate

    International Nuclear Information System (INIS)

    Drobnik, S.

    TBP in dodecane and kerosene is one of the waste solutions from the reprocessing of spent nuclear fuels by the Purex process. The following methods were investigated for removing the organic solvents: adsorption on suitable solids, extraction, reaction with neutral salts, and saponification with acids or alkalis. Results showed that the best method of TBP removal is saponification with alkali hydroxides, either with dibutyl phosphate or with ortho-phosphate

  3. Phosphorus release from phosphate rock and iron phosphate by low-molecular-weight organic acids.

    Science.gov (United States)

    Xu, Ren-kou; Zhu, Yong-guan; Chittleborough, David

    2004-01-01

    Low-molecular-weight(LMW) organic acids widely exist in soils, particularly in the rhizosphere. A series of batch experiments were carried out to investigate the phosphorus release from rock phosphate and iron phosphate by low-molecular-weight organic acids. Results showed that citric acid had the highest capacity to solubilize P from both rock and iron phosphate. P solubilization from rock phosphate and iron phosphate resulted in net proton consumption. P release from rock phosphate was positively correlated with the pKa values. P release from iron phosphate was positively correlated with Fe-organic acid stability constants except for aromatic acids, but was notcorrelated with pKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearly. Addition of phenolic compounds further increased the P release from iron phosphate. Initial solution pH had much more substantial effect on P release from rock phosphate than from iron phosphate.

  4. Method of decomposing treatment for radioactive organic phosphate wastes

    International Nuclear Information System (INIS)

    Uki, Kazuo; Ichihashi, Toshio; Hasegawa, Akira; Sato, Tatsuaki

    1985-01-01

    Purpose: To decompose the organic phosphoric-acid ester wastes containing radioactive material, which is produced from spent fuel reprocessing facilities, into inorganic materials using a simple device, under moderate conditions and at high decomposing ratio. Method: Radioactive organic phosphate wates are oxidatively decomposed by H 2 O 2 in an aqueous phosphoric-acid solution of metal phosphate salts. Copper phosphates are used as the metal phosphate salts and the decomposed solution of the radioactive organic phosphate wastes is used as the aqueous solution of the copper phosphate. The temperature used for the oxidizing decomposition ranges from 80 to 100 0 C. (Ikeda, J.)

  5. Phosphate-rich sedimentary rocks: significance for organic facies and petroleum exploration

    Energy Technology Data Exchange (ETDEWEB)

    Waples, D W

    1982-03-01

    Phosphorus-bearing rocks and sediments can be divided into two genetically distinct classes: phosphatic shales or limestones and phosphorites. Phosphatic shales are primary sediments in which phosphate nodules or micronodules have formed diagenetically by precipitation of calcium phosphates derived mainly from organic phosphorus. The nodules form in reducing environments at shallow depths within the sediments, where loss of phosphate by diffusion to the overlying water column is minimized. Highly biogenic sediments containing large amounts of organic matter and some fine clastic debris provide ideal environments for the formation of phosphate nodules. Phosphorites, in contrast, represent concentrated accumulations of reworked phosphate nodules which originated in phosphatic shales or limestones. Currents, wave action, recrystallization, and erosion and resedimentation are important mechanisms in the concentration process. Phosphatic shales and limestones may become excellent oil source rocks if thermal maturity is achieved. They are useful facies indicators for anoxic or nearly anoxic depositional environments, and are often associated with restricted basins, or, during certain geologic periods, with broad shelves developed during transgressions. Phosphorites, in contrast, are often correlated with sea-level regressions or uplifts. They are modest source rocks because of their low organic carbon contents and the fact that they were reworked under oxidizing conditions. Nevertheless, because phosphorites are derived from, and often grade into, phosphatic shales, they also are of potential utility in the search for oil source beds.

  6. Determining Inorganic and Organic Carbon.

    Science.gov (United States)

    Koistinen, Jaana; Sjöblom, Mervi; Spilling, Kristian

    2017-11-21

    Carbon is the element which makes up the major fraction of lipids and carbohydrates, which could be used for making biofuel. It is therefore important to provide enough carbon and also follow the flow into particulate organic carbon and potential loss to dissolved organic forms of carbon. Here we present methods for determining dissolved inorganic carbon, dissolved organic carbon, and particulate organic carbon.

  7. Polarographic behaviour of uranium (VI) in tributyl phosphate organic solutions

    International Nuclear Information System (INIS)

    Degueldre, C.A.; Meklati, M.

    1984-01-01

    U(VI) determination by D.C. and differential pulse polarography was studied in the organic solutions derived from tributyl phosphate - diluent extracts (after separation from nitric acid media) along with a selected aprotic solvent (i.e.: propylene carbonate and N,N-dimethylacetamide). Miscibility of the TBP-diluent (e.g. cyclohexane, n-hexane, kerosene, n-dodecane) phase with nitric acid as supporting electrolyte, either by addition or already present in the extract was larger in DMA than in PC. In the DMA organic mixture, U(VI) exhibited a DPP peak due to a one electron step, with Esub(p)=-0.4 V (position connected with H 2 O and HNO 3 concentrations). This peak which was proportionnel to the U(VI) concentration from 5x10 -6 to 10 -3 M can be used to determinate directly hexavalent uranium in the industrial organic extraction phases TBP-diluent. (orig.)

  8. Hyperpolarised Organic Phosphates as NMR Reporters of Compartmental pH

    DEFF Research Database (Denmark)

    Jensen, Pernille Rose; Meier, Sebastian

    2016-01-01

    Organic phosphate metabolites contain functional groups withpKa values near the physiologic pH range, yielding pH-dependet 13C chemical shift changes of adjacent quaternary carbon sites.Whenformed in defined cellular compartmentsfrom exogenoushyperpolarised13Csubstrates,metabolites thuscanyieldlo......Organic phosphate metabolites contain functional groups withpKa values near the physiologic pH range, yielding pH-dependet 13C chemical shift changes of adjacent quaternary carbon sites.Whenformed in defined cellular compartmentsfrom exogenoushyperpolarised13Csubstrates...

  9. Chemical activation of gasification carbon residue for phosphate removal

    Science.gov (United States)

    Kilpimaa, Sari; Runtti, Hanna; Lassi, Ulla; Kuokkanen, Toivo

    2012-05-01

    Recycling of waste materials provides an economical and environmentally significant method to reduce the amount of waste. Bioash formed in the gasification process possesses a notable amount of unburned carbon and therefore it can be called a carbon residue. After chemical activation carbon residue could be use to replace activated carbon for example in wastewater purification processes. The effect of chemical activation process variables such as chemical agents and contact time in the chemical activation process were investigated. This study also explored the effectiveness of the chemically activated carbon residue for the removal of phosphate from an aqueous solution. The experimental adsorption study was performed in a batch reactor and the influence of adsorption time, initial phosphate concentration and pH was studied. Due to the carbon residue's low cost and high adsorption capacity, this type of waste has the potential to be utilised for the cost-effective removal of phosphate from wastewaters. Potential adsorbents could be prepared from these carbonaceous by-products and used as an adsorbent for phosphate removal.

  10. Investigation of the benzotriazole as addictive for carbon steel phosphating

    International Nuclear Information System (INIS)

    Annies, V.; Cunha, M.T.; Rodrigues, P.R.P.; Banczek, E.P.; Terada, M.

    2010-01-01

    This work studied the viability of substitution of sodium nitrite (NaNO 2 ) for benzotriazole (BTAH) in the zinc phosphate bath (PZn+NaNO 2 ) for phosphating of carbon steel (SAE 1010). The characterization of the samples was carried out by Scanning Electron Microscopy, Optical Microscopy and X-ray diffraction. The chemical composition was evaluated by Energy Dispersive Spectroscopy. The corrosion behavior of the samples was investigated by Open Circuit Potential, Electrochemical Impedance Spectroscopy and Anodic Potentiodynamic Polarization Curves in a 0.5 mol L -1 NaCl electrolyte. The experimental results showed that the phosphate layer obtained in the solution with benzotriazole (PZn+BTAH) presented better corrosion resistance properties than that obtained in sodium nitrite. The results demonstrated that the sodium nitrite NaNO 2 can be replaced by benzotriazole (BTAH) in zinc phosphate baths. (author)

  11. Phosphate binding therapy in dialysis patients: focus on lanthanum carbonate

    Directory of Open Access Journals (Sweden)

    Ismail A Mohammed

    2008-11-01

    Full Text Available Ismail A Mohammed, Alastair J HutchisonManchester Institute of Nephrology and Transplantation, Manchester Royal Infirmary, Oxford Road, Manchester, UKAbstract: Hyperphosphatemia is an inevitable consequence of end stage chronic kidney disease and is present in the majority of dialysis patients. Recent observational data has associated hyperphosphatemia with increased cardiovascular mortality among dialysis patients. Dietary restriction of phosphate and current dialysis prescription practices are not enough to maintain serum phosphate levels within the recommended range so that the majority of dialysis patients require oral phosphate binders. Unfortunately, conventional phosphate binders are not reliably effective and are associated with a range of limitations and side effects. Aluminium-containing agents are highly efficient but no longer widely used because of well established and proven toxicity. Calcium based salts are inexpensive, effective and most widely used but there is now concern about their association with hypercalcemia and vascular calcification. Sevelamer hydrochloride is associated with fewer adverse effects, but a large pill burden and high cost are limiting factors to its wider use. In addition, the efficacy of sevelamer as a monotherapy in lowering phosphate to target levels in severe hyperphosphatemia remains debatable. Lanthanum carbonate is a promising new non-aluminium, calcium-free phosphate binder. Preclinical and clinical studies have demonstrated a good safety profile, and it appears well tolerated and effective in reducing phosphate levels in dialysis patients. Its identified adverse events are apparently mild to moderate in severity and mostly GI related. It appears to be effective as a monotherapy, with a reduced pill burden, but like sevelamer, it is significantly more expensive than calcium-based binders. Data on its safety profile over 6 years of treatment are now available.Keywords: hyperphosphatemia, lanthanum

  12. Biomineralization of carbonate and phosphate by moderately halophilic bacteria

    NARCIS (Netherlands)

    Sánchez-Román, Mónica; Rivadeneyra, Maria A.; Vasconcelos, Crisogono; McKenzie, Judith A.

    We investigated the precipitation of carbonate and phosphate minerals by 19 species of moderately halophilic bacteria using media with variable Mg 2+/Ca2+ ratios. The precipitated minerals were calcite, magnesium (Mg) calcite, and struvite (MgNH4PO4· 6H2O) in variable proportions depending on the

  13. Competitive sorption between glyphosphate and inorganic phosphate on clay minerals and low organic matter soils

    International Nuclear Information System (INIS)

    Dion, H.M.; Hill, H.H.Jr.; Washington State Univ., Pullmann, WA; Harsh, J.B.; Washington State Univ., Pullmann, WA

    2001-01-01

    Inorganic phosphate may influence the adsorption of glyphosate to soil surface sites. It has been postulated that glyphosphate sorption is dominated by the phosphoric acid moiety, therefore, inorganic phosphate could compete with glyphosate for surface sorption sites. Sorption of glyphosate is examined in low organic carbon systems where clay minerals dominate the available adsorption sites using 32 P-labeled phosphate and 14 C-labeled glyphosate to track sorption. Glyphosate sorption was found to be strongly dependent on phosphate additions. Isotherms were generally of the L type, which is consistent with a limited number of surface sites. Most sorption on whole soils could be accounted for by sorption observed on model clays of the same mineral type as found in the soils. (author)

  14. Application of Potential Phosphate-Solubilizing Bacteria and Organic Acids on Phosphate Solubilization from Phosphate Rock in Aerobic Rice

    Directory of Open Access Journals (Sweden)

    Qurban Ali Panhwar

    2013-01-01

    Full Text Available A study was conducted at Universiti Putra Malaysia to determine the effect of phosphate-solubilizing bacteria (PSB and organic acids (oxalic & malic on phosphate (P solubilization from phosphate rock (PR and growth of aerobic rice. Four rates of each organic acid (0, 10, 20, and 30 mM, and PSB strain (Bacillus sp. were applied to aerobic rice. Total bacterial populations, amount of P solubilization, P uptake, soil pH, and root morphology were determined. The results of the study showed significantly high P solubilization in PSB with organic acid treatments. Among the two organic acids, oxalic acid was found more effective compared to malic acid. Application of oxalic acid at 20 mM along with PSB16 significantly increased soluble soil P (28.39 mg kg−1, plant P uptake (0.78 P pot−1, and plant biomass (33.26 mg. Addition of organic acids with PSB and PR had no influence on soil pH during the planting period. A higher bacterial population was found in rhizosphere (8.78 log10 cfu g−1 compared to the nonrhizosphere and endosphere regions. The application of organic acids along with PSB enhanced soluble P in the soil solution, improved root growth, and increased plant biomass of aerobic rice seedlings without affecting soil pH.

  15. Phosphate and organic fertilizer recovery from black water

    NARCIS (Netherlands)

    Tervahauta, T.H.

    2014-01-01

    In this thesis the integration of treatment systems for black and grey water was investigated to improve resource recovery within source-separated sanitation concepts. Special focus was set on phosphate and organic fertilizer recovery from vacuum collected black water. Currently, the soil

  16. 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

  17. Application of phosphating techniques to aluminium and carbon steel surfaces using nitro guanidine as oxidizing agent

    International Nuclear Information System (INIS)

    Briseno M, S.A.

    1995-01-01

    Phosphate coatings are inorganic crystalline deposits laid down uniformly on properly prepared surfaces by a chemical reaction with the treated base metal. The reaction consists in dissolving some surface metal by acid attack and then causing surface neutralization of the phosphate solution with consequent precipitation of the phosphate coating. Phosphate coatings do not provide appreciable corrosion protection in themselves. They are useful mainly as a base for paints, ensuring good adherence of paint to steel and decreasing the tendency for corrosion to under cut the paint film at scratches or other defects. In this work firstly were realized phosphate on standard carbon steel, employing technical of cold phosphate (at 40 Centigrade degrees and with a treatment time of 30 minutes) and hot phosphate (at 88 Centigrade degrees and with a treatment time of 15 minutes), where with this last were obtained the best results. Both methods used phosphate solutions of Zn/Mn and using as catalyst Nitro guanidine. Aluminium surfaces were phosphate used solutions of Cr and as catalyst Sodium bi fluoride. The phosphating on this surface were realized at temperature of 50 Centigrade degrees and with a treatment time of 10 minutes. In this work were obtained a new phosphate coatings on steel surfaces, these coatings were realized with a phosphate solution manufactured with the precipitates gathered during the hot phosphating on carbon steel. These coatings show excellent physical characteristics and of corrosion resistance. Were determined the physical testings of the coatings phosphate obtained on carbon steel and aluminium surfaces. These testing were: roughness, thickness, microhardness and adhesion. The best results were showed in carbon steel phosphate with precipitated solutions. The technical of analysis for activation with thermic neutrons was used to determine the phosphate coatings composition. Finally, corrosion testings were realized by means of two methods

  18. Capacitive, deionization with carbon aerogel electrodes: Carbonate, sulfate, and phosphate

    International Nuclear Information System (INIS)

    Farmer, J.C.; Fix, D.V.; Mack, G.V.; Pekala, R.W.; Poco, J.F.

    1995-01-01

    A process for the capacitive deionization (CDI) of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Unlike ion exchange, one of the more conventional deionization processes, no chemicals are required for regeneration of the system. Electricity is used instead. Water with various anions and cations is pumped through the electrochemical cell. After polarization, ions are electrostatically removed from the water and held in the electric double layers formed at the surfaces of electrodes. The water leaving the cell is purified, as desired. The effects of cell voltage on the electrosorption capacities for Na 2 SO 4 , Na 3 PO 4 , and Na 2 CO 3 have been investigated and are reported here. Results for NaCl and NaNO 3 have been reported previously. Possible applications for CDI are as a replacement for ion exchange processes which remove heavy metals and radioisotopes from process and waste water in various industries, as well as to remove inorganic ions from feedwater for fossil and nuclear power plants

  19. Pore-Water Carbonate and Phosphate As Predictors of Arsenate Toxicity in Soil.

    Science.gov (United States)

    Lamb, Dane T; Kader, Mohammed; Wang, Liang; Choppala, Girish; Rahman, Mohammad Mahmudur; Megharaj, Mallavarapu; Naidu, Ravi

    2016-12-06

    Phytotoxicity of inorganic contaminants is influenced by the presence of competing ions at the site of uptake. In this study, interaction of soil pore-water constituents with arsenate toxicity was investigated in cucumber (Cucumis sativa L) using 10 contrasting soils. Arsenate phytotoxicity was shown to be related to soluble carbonate and phosphate. The data indicated that dissolved phosphate and carbonate had an antagonistic impact on arsenate toxicity to cucumber. To predict arsenate phytotoxicity in soils with a diverse range of soil solution properties, both carbonate and phosphate were required. The relationship between arsenic and pore-water toxicity parameters was established initially using multiple regression. In addition, based on the relationship with carbonate and phosphate we successively applied a terrestrial biotic ligand-like model (BLM) including carbonate and phosphate. Estimated effective concentrations from the BLM-like parametrization were strongly correlated to measured arsenate values in pore-water (R 2 = 0.76, P soils.

  20. Organic electrochemistry and carbon electrodes

    International Nuclear Information System (INIS)

    Weinberg, N.

    1983-01-01

    Carbons are often used in organic electrosynthesis and are critical as anodes or cathodes to certain reactions. Too often the surface properties of carbons have been left uncharacterized in relation to the reaction; however, these physical and chemical properties of carbons are important to the nature of the products, and the selectivity. Examples presented include the Kolbe reaction, the oxidation of aromatics in presence of carboxylate salts, electrofluorination of organics, acetamidation of aromatics, the hydrodimerization of formaldehyde and the oxidation of carbon fibers. These reactions apparently involve special surface characteristics: structure, surface area, stabilized surface sites, and the presence or absence of significant ''oxide'' functionality

  1. Phosphate incorporation in organic compounds in roots of maize

    International Nuclear Information System (INIS)

    Michalik, I.; Ivanko, S.

    1976-01-01

    32 P incorporation and metabolism was investigated for short exposure times of 1 sec, 10 sec and 1, 10, 30 and 120 min. By stepwise extraction with a methanol-chloroform-formic acid-water mixture, various fractions of P compounds were obtained. Low-molecular acid-soluble P compounds were separated by one-dimensional paper chromatography. Of the total amount of 32 P absorbed by the roots of maize in the form of phosphate ions during the short incubation time of 1 sec, more than 33% was incorporated into organic compounds. With increasing incubation time, the proportion of 32 P in low-molecular organic compounds increased with the decreasing proportion of inorganic phosphorus. In the 1 sec, exposure incorporation was found in 3 low-molecular organic compounds only, namely ATP, ADP and diphosphoglyceric acid. The 32 P incorporation into ATP and ADP, in contrast with incorporation into diphosphoglyceric acid, increased markedly with increased exposure time. (author)

  2. Biological phosphate removal using a degradable carbon source produced by hydrothermal treatment of excess sludge

    Directory of Open Access Journals (Sweden)

    L. H. Haraguchi

    2006-03-01

    Full Text Available The possibility of reusing excess sludge treated by hydrothermal reaction for the purpose of improving the efficiency of the enhanced biological phosphate removal (EBPR process was investigated. Excess sludge from a fish-processing industry located in Japan was treated in high-temperature and high-pressure water, at a reaction temperature ranging from 200 to 400ºC, a pressure of 1.8 to 30MPa and a constant reaction time of 7 min. For the conditions tested, the results showed that when the reaction temperature was increased the content of readily biodegradable substrate in the total COD Cr increased. In addition, the amount of some volatile fatty acids (VFAs produced by the hydrothermal reaction increased as reaction temperature increased. From the phosphate release tests under anaerobic conditions, it was possible to demonstrate that not only the VFAs, but also the readily and slowly biodegradable substrates are used as potential carbon source by the phosphate-accumulating organisms (PAOs.

  3. Comparative efficiency of high (trip super phosphate) and low (rock phosphate) grade p nutrition source enriched with organic amendment in maize crop

    International Nuclear Information System (INIS)

    Sabah, N.U.; Sarwar, G.; Tahir, M.A.

    2016-01-01

    Pakistan falls under arid to semi-arid climate and therefore, Pakistani soils are sufferer of phosphorus deficiency. Costly phosphatic commercial fertilizers and their unavailability at the time of crop demand is the burning issue in Pakistan. Under such circumstances, use of locally available rock phosphate (RP) grasps the interest of researchers now a day. Pakistan has blessed with considerable quantity of cheaper low grade RP in Abbottabad and Hazara districts of KPK province. Due to this scenario, a pot experiment was carried out to evaluate growth efficiency of maize crop by adding organic manure fortified with RP in comparison with TSP in normal soil (pHs= 8.15, ECe= 1.28 dSm-1, SAR = 4.77 mmol L-1, saturation percentage = 29% and sandy clay loam texture). The study was comprised of 7 treatments replicated three times including: T1 = Control (0 P); T2 = Recommended NK + organic material; T3 = Recommended NK + RRP; T4 = Recommended NK + RRP + OM; T5 = Recommended NK + TSP; T6 = Recommended NK + TSP + OM and T7 = N + K + TSP + 0.5 Organic manure. It was concluded that integrated use of organic amendment with RP (Local Hazara Red Rock Phosphate) and TSP proved superior as compared to their sole use on maize crop growth. A significant increase in available P concentration of the growth medium was observed due to addition of organic material along with TSP as a source of P. Addition of organic material also enhanced the soil carbon level as compared to control. It can be concluded that rock phosphate (RP) could be an effective and economic substitution for TSP when it is integrated with suitable organic amendment with specific size. (author)

  4. The Changes of P-fractions and Solubility of Phosphate Rock in Ultisol Treated by Organic Matter and Phosphate Rock

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    Heru Bagus Pulunggono

    2012-09-01

    Full Text Available Phosphorus (P is one of the essential elements for plant, however, its availability is mostly very low in acid soils. It is well documented that application of phosphate rock and organic matter are able to change the level of availability of P-form in acid soils. The objective of the research were to evaluate the changes of P-fractions ( resin-P, NaHCO3-Pi, and NaHCO3-Po and phosphate rock dissolution which were induced by application of organic matter (Imperata cylindrica, Pueraria javanica, dan Colopogonium mucunoides and phosphate rock in Utisol Lampung. The experiment was designed in a completely randomized design with three factors and three replications. The first factor was the types of organic matter (I. cylindrica, P. javanica, and C. mucunoides, the second factor was the rate of organic matter (0, 2.5, and 5%, and the third factor was the rate of phosphate rock (0, 40, and 80 mg P kg-1. The results showed that in the rate of 0 and 1% organic matter, the type of organic matter did not affect P-fraction of NaHCO3-Pi, but in the rate of 2.5 and 5%, NaHCO3-Pi due to application of P. javanica, and C. mucunoides higher than due to application of I. cylindrica. However, the increasing rate of organic matter increased NaHCO3-Pi. Then, P-fraction of Resin-Pi was affected by the type of organic matter, the rate of organic matter, and the rate of phosphate rock, respectively. P-fraction of resin-Pi due to application of P. javanica, and C. mucunoides was higher than due to application of I. cylindrica, but the effect of P. javanica, and C. mucunoides was not different. Increasing the rate of organic matter and phosphate rock increased P-fraction of resin-Pi and NaHCO3-Pi, but P-fraction of NaHCO3-Po was not affected by all treatments. Meanwhile, dissolution of phosphate rock was affected by the kind of organic matter and soil reaction. In the rate of 5% organic matter, dissolution of phosphate rock by application of I. cylindrica (70% was higher

  5. Investigation of Organic Matters and their Roles in Deposition and Phosphate Mineralization in the Kuh-e-Sefid Deposit, Ramhormoz

    Directory of Open Access Journals (Sweden)

    Houshang Pourkaseb

    2017-07-01

    Full Text Available Introduction It has been recently stated that phosphorite deposits are in fact marine biogenic materials, due to bacterial activity producing bio-apatite. In addition, Phosphorites contain 15–20 wt.% P2O5 (Tzifas et al., 2014. In this deposit, phosphate mineralization has occurred as phosphorite lenses with Eocene age within the Pabdeh Formation, with thickness up to 1.5 meters and width of 15 meters and its hosted rock is black shale. According to the presence of indices of fossils such as Globorotalia, Hantkenina, its age can be attributed to the middle Eocene. The Pabdeh formation is a very rich organic matter in addition to the presence of phosphate (Damiri, 2011. The formation due to planktonic foraminifera rich in organic matter is like the hydrocarbon source rock (Daneshian et al., 2012. In marine basins where upwelling and productivity are limited, phosphates may develop outside of microbial cells and also within bacterial cellular structures, formed by slow bacterial assimilation of phosphorus from assaying organic matter in areas of restricted sedimentation (O’Brine et al., 1981. It is therefore suggested that the upwelling currents did that in the recycling of phosphorus from dead organisms such as fishes and other marine vertebrates. The aim of this study is investigation of organic matter’s species and their roles in deposition and phosphate mineralization in the Kuh-e-Sefid phosphate deposit using XRD, FTIR and Rock-Eval pyrolysis. Materials and methods In field observations, 12 samples were selected and they were taken from units of phosphate and shale host rock in the Kuh-e-Sefid phosphate ore deposit. Ten cross sections were studied by conventional microscopic methods. Rock-Eval analysis was used in order to determine the organic carbon in the geology Department of the Shahid Chamran University of Ahvaz. The Phosphorite samples were determined by XRD at the Kansaran Binaloud Company in the Science and Technology campus in

  6. Phosphate incorporation in organic compounds in roots of maize

    Energy Technology Data Exchange (ETDEWEB)

    Michalik, I; Ivanko, S [Vysoka Skola Polnohospodarska, Nitra (Czechoslovakia)

    1976-01-01

    /sup 32/P incorporation and metabolism was investigated for short exposure times of 1 sec, 10 sec and 1, 10, 30 and 120 min. By stepwise extraction with a methanol-chloroform-formic acid-water mixture, various fractions of P compounds were obtained. Low-molecular acid-soluble P compounds were separated by one-dimensional paper chromatography. Of the total amount of /sup 32/P absorbed by the roots of maize in the form of phosphate ions during the short incubation time of 1 sec, more than 33% was incorporated into organic compounds. With increasing incubation time, the proportion of /sup 32/P in low-molecular organic compounds increased with the decreasing proportion of inorganic phosphorus. In the 1 sec, exposure incorporation was found in 3 low-molecular organic compounds only, namely ATP, ADP and diphosphoglyceric acid. The /sup 32/P incorporation into ATP and ADP, in contrast with incorporation into diphosphoglyceric acid, increased markedly with increased exposure time.

  7. Characterisation of Phosphate Accumulating Organisms and Techniques for Polyphosphate Detection: A Review

    Directory of Open Access Journals (Sweden)

    Cédric Tarayre

    2016-05-01

    Full Text Available Phosphate minerals have long been used for the production of phosphorus-based chemicals used in many economic sectors. However, these resources are not renewable and the natural phosphate stocks are decreasing. In this context, the research of new phosphate sources has become necessary. Many types of wastes contain non-negligible phosphate concentrations, such as wastewater. In wastewater treatment plants, phosphorus is eliminated by physicochemical and/or biological techniques. In this latter case, a specific microbiota, phosphate accumulating organisms (PAOs, accumulates phosphate as polyphosphate. This molecule can be considered as an alternative phosphate source, and is directly extracted from wastewater generated by human activities. This review focuses on the techniques which can be applied to enrich and try to isolate these PAOs, and to detect the presence of polyphosphate in microbial cells.

  8. Strontium and magnesium substituted dicalcium phosphate dehydrate coating for carbon/carbon composites prepared by pulsed electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shou-jie, E-mail: jlliushoujie@126.com; Li, He-jun, E-mail: lihejun@nwpu.edu.cn; Zhang, Lei-lei, E-mail: zhangleilei@nwpu.edu.cn; Feng, Lei, E-mail: fengleijinan@163.com; Yao, Pei, E-mail: 1113923884@qq.com

    2015-12-30

    Graphical abstract: The potentiodynamic polarization curve shows that the SM-DCPD coating can dramatically enhance the corrosion potential (E{sub corr}) value and meanwhile decrease the corrosion current density (I{sub corr}) of C/C composites. - Highlights: • Strontium and magnesium substituted dicalcium phosphate dehydrate coatings for carbon/carbon composites were synthesized by pulsed eletrodeposition. • Strontium and magnesium substituted dicalcium phosphate dehydrate coated carbon/carbon composites exhibited excellent bioactivity in vivo. • Strontium and magnesium substituted dicalcium phosphate dehydrate coated carbon/carbon composites showed lower corrosion rate with the comparison to pure carbon/carbon composites. - Abstract: Trace elements substituted apatite coatings have received a lot of interest recently as they have many benefits. In this work, strontium and magnesium substituted DCPD (SM-DCPD) coatings were deposited on carbon/carbon (C/C) composites by pulsed electrodeposition method. The morphology, microstructure, corrosion resistance and in vitro bioactivity of the SM-DCPD coatings are analyzed. The results show that the SM-DCPD coatings exhibit a flake-like morphology with dense and uniform structure. The SM-DCPD coatings could induce the formation of apatite layers on their surface in simulated body fluid. The electrochemical test indicates that the SM-DCPD coatings can evidently decrease the corrosion rate of the C/C composites in simulated body fluid. The SM-DCPD has potential application as the bioactive coatings.

  9. Wet-Oxidation of Spent Organic Waste Tri-butyl Phosphate/Diluents

    International Nuclear Information System (INIS)

    El-Dessouky, M.I.; Abed El-Aziz, M.M.; El-Mossalamy, E.H.; Aly, H.F.

    1999-01-01

    Tri-Butyl Phosphate was used in reprocessing of spent nuclear fuel in the purex process. The amount of uranium retained in the organic phase depends on the type of TBP/Diluent. Destruction of spent TBP is of high interest in waste management. In the present work, oxidative degradation of TBP diluted with kerosene, carbon tetrachloride, benzene and toluene using potassium permanganate as oxidant was carried out to produce stable inorganic dry particle residue which is then immobilized in different matrices. The different factors affecting the destruction of spent waste was investigated. The up take and decontamination factor for both 152 and 154 Eu and 181 Hf and the analysis of the final product have been studied

  10. Developing porous carbon with dihydrogen phosphate groups as sulfur host for high performance lithium sulfur batteries

    Science.gov (United States)

    Cui, Yanhui; Zhang, Qi; Wu, Junwei; Liang, Xiao; Baker, Andrew P.; Qu, Deyang; Zhang, Hui; Zhang, Huayu; Zhang, Xinhe

    2018-02-01

    Carbon matrix (CM) derived from biomass is low cost and easily mass produced, showing great potential as sulfur host for lithium sulfur batteries. In this paper we report on a dihydrogen phosphate modified CM (PCM-650) prepared from luffa sponge (luffa acutangula) by phosphoric acid treatment. The phosphoric acid not only increases the surface area of the PCM-650, but also introduces dihydrogen phosphate onto PCM-650 (2.28 at% P). Sulfur impregnated (63.6 wt%) PCM-650/S, in comparison with samples with less dihydrogen phosphate LPCM-650/S, shows a significant performance improvement. XPS analysis is conducted for sulfur at different stages, including sulfur (undischarged), polysulfides (discharge to 2.1 V) and short chain sulfides (discharge to 1.7 V). The results consistently show chemical shifts for S2p in PCM-650, suggesting an enhanced adsorption effect. Furthermore, density functional theory (DFT) calculations is used to clarify the molecular binding: carbon/sulfur (0.86 eV), carbon/Li2S (0.3 eV), CH3-O-PO3H2/sulfur (1.24 eV), and CH3-O-PO3H2/Li2S (1.81 eV). It shows that dihydrogen phosphate group can significantly enhance the binding with sulfur and sulfide, consistent with XPS results. Consequently a CM functionalised with dihydrogen phosphate shows great potential as the sulfur host in a Li-S battery.

  11. Characterization of the denitrifying fraction of phosphate accumulating organisms in biological phosphate removal

    DEFF Research Database (Denmark)

    Meinhold, Jens; Filipe, Carlos D.M.; Daigger, Glen T.

    1999-01-01

    fractions of PAO are performed and compared. This study extends on previously reported results (Kerrn-Jespersen and Henze, 1993) in that the pH was controlled to around pH 7 to assure that phosphate precipitation was minimal, and in the measurement of PHB and PHV. With regards to the latter, the paper also...

  12. Assessment of phosphate binding by sevelamer carbonate powder for oral suspension mixed in foods.

    Science.gov (United States)

    Hanus, Martin; Zhorov, Eugene; Brommage, Deborah; Plone, Melissa; Holmes-Farley, Stephen Randall

    2012-01-01

    This study investigated mixing sevelamer carbonate powder with foods and beverages other than water. Food samples, including applesauce, oatmeal, chicken, protein powder, scrambled eggs, ginger ale, and diet ginger ale, were subjected to an in vitro assay, and the difference in the amount of phosphate bound between samples pre-exposed to foods and samples where the drug was exposed to foods concurrently was determined Under these assay conditions, pre-exposure to sevelamer carbonate powder had no effect on the ability to bind phosphate. Clinical testing is needed to further evaluate this finding.

  13. The Use of Ameliorant Fe3+ and Rock Phosphates in Peat Soil at Several Water Condition on the P Content of Plants Rice and Carbon Emission

    Directory of Open Access Journals (Sweden)

    Nelvia

    2009-09-01

    Full Text Available The addition of ameliorant Fe3+ and rock phosphates containing high Fe cation can reduce effect of toxic organic acids, increase peat stability through formation of complex compounds and reduce carbon emission. The research was conducted in the laboratory and green house of the Departement of Soil Science, Faculty of Agriculture, Bogor Agriculture University. Peat samples with hemic degree of decomposition were taken from Riau. Rock phosphates were taken from the rock phosphates of PT. Petrokimia Gresik, Christmas Island phosphates, and Huinan China and FeCl3.6H2O was used as the other Fe3+ source. The aims of the research were to study (a the effect of the applications of ameliorant Fe3+ and rock phosphates on the P content of plants dan (b the effect of the application ameliorant Fe3+ and the contribution of Fe cation in rock phosphates in the decrease of carbon emission. The results showed that the P content of plants rice increased 58 – 286% with the applications of ameliorant Fe3+ and rock phosphates. The estimation of carbon loss through CO2 and CH4 emissions from peats if planted continuously with rice was around 2.5, 2.2 and 2.6 Mg of C ha-1 year-1 respectively in field capacity condition, two times of field capacity condition, and 5 cm of saturated condition. The application of ameliorant Fe3+ and rock phosphates containing high Fe cation increased the stability of peats and reduced the carbon loss around 1.7 Mg of C ha-1 year-1 (64% in 5 cm of saturated condition, 1.3 Mg of C ha-1 year-1 (58% in two times of field capacity condition, and 1.0 Mg of C ha-1 year-1 (41% in field capacity condition.

  14. From energy-rich phosphate compounds to warfare agents: A review on the chemistry of organic phosphate compounds

    Directory of Open Access Journals (Sweden)

    Luciano Albino Giusti

    2008-12-01

    Full Text Available The chemistry of the phosphorus-oxygen bond is widely used in biological systems in many processes, such as energy transduction and the storage, transmission and expression of genetic information, which are essential to living beings in relation to a wide variety of functions. Compounds containing this bond have been designed for many purposes, ranging from agricultural defense systems, in order to increase food production, to nerve agents, for complaining use in warfare. In this review, features related to the chemistry of organic phosphate compounds are discussed, with particular emphasis on the role of phosphate compounds in biochemical events and in nerve agents. To this aim, the energy-rich phosphate compounds are focused, particularly the mode of their use as energy currency in cells. Historical and recent studies carried out by research groups have tried to elucidate the mechanism of action of enzymes responsible for energy transduction through the use of biochemical studies, enzyme models, and artificial enzymes. Finally, recent studies on the detoxification of nerve agents based on phosphorous esters are presented, and on the utilization of chromogenic and fluorogenic chemosensors for the detection of these phosphate species.

  15. Organic carbon content of tropical zooplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.

    In the Zuari and Mandovi estuaries variations in organic carbon of zooplankton are 26.4-38.8 and 24-39.9% of dry weight respectively. Maximum carbon content of estuarine zooplankton is observed in November. Organic carbon in nearshore and oceanic...

  16. Effects of Inulin and Sodium Carbonate in Phosphate-Free Restructured Poultry Steaks

    Science.gov (United States)

    Öztürk, B.; Serdaroğlu, M.

    2017-09-01

    Recently inorganic phosphates used in meat product formulations have caused negative impact on consumers due to their potential health risks. Therefore, utilization of natural ingredients as phosphate replacers has come into prominence as a novel research topic to meet consumer demands for clean-label trends. In this study, we objected to investigate the effects of inulin utilization either in the powder or gelled form, alone or in combination with sodium carbonate on quality of phosphate-free restructured chicken steaks. Total moisture, protein, lipid and ash values of the trial groups were in the range of 71.54-75.46%, 22.60-24.31%, 0.94-1.70% and 1.45-2.13%, respectively. pH of the samples was between 6.18-6.39, significant increments were recorded in samples containing inulin with sodium carbonate. L*, a* and b* values were recorded as 78.92-81.05, 1.76-3.05 and 10.80-11.94, respectively, where use of gelled inulin resulted in changes of L* and a* values. Utilization of inulin in combination with sodium carbonate decreased cook loss and enhanced product yield. Sensory scores in control group with phosphate showed a similar pattern to sensory scores in groups with inulin and sodium carbonate. During storage, purge loss and lipid oxidation rate were similar in control and inulin + sodium carbonate samples. The results showed that use of inulin in combination with sodium carbonate provided equivalent physical, chemical and sensory quality to phosphates in restructured chicken steaks.

  17. Analysis of trehalose-6-phosphate control over carbon allocation and growth in plants

    NARCIS (Netherlands)

    Aghdasi, M.

    2007-01-01

    Trehalose is the non-reducing alpha-alpha-1, 1-linked glucose disaccharide. The biosynthesic precursor of trehalose, trehalose-6-phosphate (T6P), is essential for plant development, growth, carbon utilization and alters photosynthetic capacity but its mode of action is not underestood. This thesis

  18. 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 ...

  19. Aminopropyl-functionalized mesoporous carbon (APTMS-CMK-3) as effective phosphate adsorbent

    Science.gov (United States)

    Yang, Yanju; Wang, Juanjuan; Qian, Xiaoqing; Shan, Yuhua; Zhang, Haipeng

    2018-01-01

    Excess phosphate discharge into water bodies can lead to severe eutrophication. Adsorption has been considered as one of the most effective approaches for phosphate removal and recovery. A new aminopropyl-functionalized mesoporous carbon CMK-3 (denoted as APTMS-CMK-3) was prepared and the materials were used as adsorbents for the removal of phosphate in water. The structure, functional groups and surface charge of the materials were characterized by X-ray powder diffraction, transmission electron microscope, N2 adsorption-desorption, elemental analysis, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and zeta potential measurements. The effects of contact time, initial phosphate concentration, solution pH, coexisting anions and dissolved humic acid were studied. The adsorption capacity of APTMS-CMK-3 was 38.09 mg g-1 at the equilibrium concentration of 49.06 mg L-1, and the adsorption data were well fitted with the Freundlich model. As for the reuse of APTMS-CMK-3, a relatively stable adsorption performance was observed after five adsorption-desorption cycles. Therefore, the way of grafting aminopropyl groups on the CMK-3 efficiently enhanced the capability for phosphate adsorption, indicating that it could be used as potential adsorbents for the removal of phosphate in water.

  20. Removal of phosphate from water by activated carbon fiber loaded with lanthanum oxide

    International Nuclear Information System (INIS)

    Zhang Ling; Wan Lihua; Chang Ning; Liu Jianyong; Duan Chao; Zhou Qi; Li Xiangling; Wang Xinze

    2011-01-01

    Phosphate removal from wastewater is very important for the prevention of eutrophication. Adsorption of phosphate from water was investigated using activated carbon fiber loaded with lanthanum oxide (ACF-La) as a novel adsorbent. The effects of variables (La/ACF mass ratio, impregnation time, activation time, and activation temperature) have been studied by the single-factor method. Response surface methodology (RSM), based on three-variable-three-level Box-Behnken design (BBD), was employed to assess the individual and collective effects of the main independent parameters on the phosphate removal. The optimal conditions within the range studied for preparing ACF-La were found as follows: La/ACF mass ratio of 11.78%, activation time of 2.5 h and activation temperature at 650 ° C , respectively. The phosphate removal using the ACF-La prepared under the optimal conditions was up to 97.6% even when the phosphate concentration in water was 30 mg P/L, indicating that ACF-La may be an effective adsorbent. The results from Fourier transform infrared (FT-IR) spectroscopy and change of pH values associated with the adsorption process revealed that the probable mechanism of phosphate ions onto ACF-La was not only ion exchange and coulomb interaction, but also a result of Lewis acid-base interaction due to La-O coordination bonding.

  1. Electrochemically assisted co-deposition of calcium phosphate/collagen coatings on carbon/carbon composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xueni [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Hu Tao [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Li Hejun, E-mail: lihejun@nwpu.edu.cn [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Chen Mengdi; Cao Sheng; Zhang Leilei [C/C Composites Technology Research Center, State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an, Shaanxi 710072 (China); Hou Xianghui [Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2011-02-01

    Calcium phosphate (CaP)/collagen coatings were prepared on the surface of carbon/carbon (C/C) composites by electrochemically assisted co-deposition technique. The effects of collagen concentration in the electrolyte on morphology, structure and composition of the coatings were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The adhesive strength of the coatings was also evaluated by scratch tests and tensile bond tests. It was demonstrated that the coatings of three-dimensional collagen network structure was formed on the C/C composites from the electrolyte containing collagen. The surface of the collagen network was covered by uniform CaP aggregates. The coatings were actually composites of CaP and collagen. Hydroxyapatite (HA) was a favorable composition in the coatings with the increase of the collagen concentration in the electrolyte. The formed collagen network increased the cohesive and adhesive strength of the coatings. The adhesive strength between the coatings and substrates increased as the collagen concentration in the electrolyte increased. The coatings prepared at the collagen concentration of 500 mg/L in the electrolyte were not scraped off until the applied load reached 32.0 {+-} 2.2 N and the average tensile adhesive strength of the coatings was 4.83 {+-} 0.71 MPa. After C/C coated with composite coatings (500 mg/L) being immersed in a 10{sup -3} M Ca (OH){sub 2} solution at 30-33 deg. C for 96 h, nano-structured HA/collagen coatings similar to the natural human bone were obtained on the C/C.

  2. Changes of Phosphate Solubilizing Bacteria Population on Paddy Field with Intensive Farming became Sustainable Organic Farming System

    Directory of Open Access Journals (Sweden)

    Dermiyati

    2009-05-01

    Full Text Available The research aimed to study the change of population of phosphate solubilizing microorganisms according to the application time of bokashi which were applied continously on organic paddy rice fields since years of 2000 up to 2006. The research was conducted in a Randomized Completely Block Design in four replicates. The treatments were without bokashi (control; with intensively application of NPK fertilizers, bokashi application for 3 planting seasons (12 t ha-1, bokashi application for 4 planting seasons (16 t ha-1, bokashi application for 7 planting seasons (28 t ha-1, and bokashi application for 9 planting seasons (36 t ha-1. The results showed that the population of phosphate solubilizing microorganisms were not affected by continously applied of bokashi and did not have correlations to organic carbon, total nitrogen, ratio C/N, soil pH, and soil water content. However, the phosphate solubilizing microorganisms had played a role in the availability of the soil available-P which were shown by increasing of paddy yields year by year, although the contribution of soil phosphorus from bokashi is a relatively low. Yet, the bokashi application on the organic paddy fields did not increase the soil availble-P because most of the P which was absorbed by the plants coming from residual P fertilizers either from bokashi or SP-36 which were intensevely given before.

  3. Evaluation of biocidal efficacy of copper alloy coatings in comparison with solid metal surfaces: generation of organic copper phosphate nanoflowers.

    Science.gov (United States)

    Gutierrez, H; Portman, T; Pershin, V; Ringuette, M

    2013-03-01

    To analyse the biocidal efficacy of thermal sprayed copper surfaces. Copper alloy sheet metals containing >60% copper have been shown to exhibit potent biocidal activity. Surface biocidal activity was assessed by epifluorescence microscopy. After 2-h exposure at 20 °C in phosphate-buffered saline (PBS), contact killing of Gram-negative Escherichia coli and Gram-positive Staphylococcus epidermidis by brass sheet metal and phosphor bronze was 3-4-times higher than that by stainless steel. SEM observations revealed that the surface membranes of both bacterial strains were slightly more irregular when exposed to brass sheet metal than stainless steel. However, when exposed to phosphor bronze coating, E. coli were 3-4 times larger with irregular membrane morphology. In addition, the majority of the cells were associated with spherical carbon-copper-phosphate crystalline nanostructures characteristic of nanoflowers. The membranes of many of the S. epidermidis exhibited blebbing, and a small subset was also associated with nanoflowers. Our data indicate that increasing the surface roughness of copper alloys had a pronounced impact on the membrane integrity of Gram-positive and, to a lesser degree, Gram-negative bacteria. In the presence of PBS, carbon-copper-phosphate-containing nanoflowers were formed, likely nucleated by components derived from killed bacteria. The intimate association of the bacteria with the nanoflowers and phosphor bronze coating likely contributed to their nonreversible adhesion. Thermal spraying of copper alloys provides a strategy for the rapid coating of three-dimensional organic and inorganic surfaces with biocidal copper alloys. Our study demonstrates that the macroscale surface roughness generated by the thermal spray process enhances the biocidal activity of copper alloys compared with the nanoscale surface roughness of copper sheet metals. Moreover, the coating surface topography provides conditions for the rapid formation of organic copper

  4. Some observations on phosphate based corrosion inhibitors in preventing carbon steel corrosion

    International Nuclear Information System (INIS)

    Anupkumar, B.; Satpathy, K.K.

    2000-01-01

    Among the various types of phosphonic acid based inhibitors assayed, namely HEDP, ATMP and a commercial corrosion inhibitor (code named Betz), it was found that Betz has the maximum amount of organic phosphate followed by HEDP and ATMP. The corrosion rate studies show that Betz gives the highest inhibition efficiency followed by HEDP and ATMP. This shows that organic phosphate plays a significant role in corrosion protection. However, it was observed that due to synergestic effect, HEDP in the presence of Zn 2+ gave a better corrosion protection than Betz. The results are discussed in the light of available literature. (author)

  5. Deposition and benthic mineralization of organic carbon

    DEFF Research Database (Denmark)

    Nordi, Gunnvor A.; Glud, Ronnie N.; Simonsen, Knud

    2018-01-01

    Seasonal variations in sedimentation and benthic mineralization of organic carbon (OC) were investigated in a Faroese fjord. Deposited particulate organic carbon (POC) was mainly of marine origin, with terrestrial material only accounting for b1%. On an annual basis the POC export fromthe euphotic...

  6. Organic carbon isotope systematics of coastal marshes

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Lubberts, R.K.; Van de Plassche, O.

    1997-01-01

    Measurements of nitrogen, organic carbon and delta(13)C are presented for Spartina-dominated marsh sediments from a mineral marsh in SW Netherlands and from a peaty marsh in Massachusetts, U.S.A. delta(13)C Of organic carbon in the peaty marsh sediments is similar to that of Spartina material,

  7. Acidity controls on dissolved organic carbon mobility in organic soils

    Czech Academy of Sciences Publication Activity Database

    Evans, Ch. D.; Jones, T.; Burden, A.; Ostle, N.; Zielinski, P.; Cooper, M.; Peacock, M.; Clark, J.; Oulehle, Filip; Cooper, D.; Freeman, Ch.

    2012-01-01

    Roč. 18, č. 11 (2012), s. 3317-3331 ISSN 1354-1013 Institutional support: RVO:67179843 Keywords : acidity * dissolved organic carbon * organic soil * peat * podzol * soil carbon * sulphur Subject RIV: EH - Ecology, Behaviour Impact factor: 6.910, year: 2012

  8. Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

    Science.gov (United States)

    Schobben, Martin; van de Velde, Sebastiaan; Gliwa, Jana; Leda, Lucyna; Korn, Dieter; Struck, Ulrich; Vinzenz Ullmann, Clemens; Hairapetian, Vachik; Ghaderi, Abbas; Korte, Christoph; Newton, Robert J.; Poulton, Simon W.; Wignall, Paul B.

    2017-11-01

    Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian-Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub-)sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the observed signal of carbon

  9. Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

    Directory of Open Access Journals (Sweden)

    M. Schobben

    2017-11-01

    Full Text Available Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian–Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub-sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the

  10. Effect of calcium carbonate on hardening, physicochemical properties, and in vitro degradation of injectable calcium phosphate cements.

    NARCIS (Netherlands)

    Sariibrahimoglu, K.; Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Yubao, L.; Jansen, J.A.

    2012-01-01

    The main disadvantage of apatitic calcium phosphate cements (CPCs) is their slow degradation rate, which limits complete bone regeneration. Carbonate (CO(3)(2)(-)) is the common constituent of bone and it can be used to improve the degradability of the apatitic calcium phosphate ceramics. This study

  11. Selective removal of phosphate for analysis of organic acids in complex samples.

    Science.gov (United States)

    Deshmukh, Sandeep; Frolov, Andrej; Marcillo, Andrea; Birkemeyer, Claudia

    2015-04-03

    Accurate quantitation of compounds in samples of biological origin is often hampered by matrix interferences one of which occurs in GC-MS analysis from the presence of highly abundant phosphate. Consequently, high concentrations of phosphate need to be removed before sample analysis. Within this context, we screened 17 anion exchange solid-phase extraction (SPE) materials for selective phosphate removal using different protocols to meet the challenge of simultaneous recovery of six common organic acids in aqueous samples prior to derivatization for GC-MS analysis. Up to 75% recovery was achieved for the most organic acids, only the low pKa tartaric and citric acids were badly recovered. Compared to the traditional approach of phosphate removal by precipitation, SPE had a broader compatibility with common detection methods and performed more selectively among the organic acids under investigation. Based on the results of this study, it is recommended that phosphate removal strategies during the analysis of biologically relevant small molecular weight organic acids consider the respective pKa of the anticipated analytes and the detection method of choice. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Mobility of organic carbon from incineration residues

    International Nuclear Information System (INIS)

    Ecke, Holger; Svensson, Malin

    2008-01-01

    Dissolved organic carbon (DOC) may affect the transport of pollutants from incineration residues when landfilled or used in geotechnical construction. The leaching of dissolved organic carbon (DOC) from municipal solid waste incineration (MSWI) bottom ash and air pollution control residue (APC) from the incineration of waste wood was investigated. Factors affecting the mobility of DOC were studied in a reduced 2 6-1 experimental design. Controlled factors were treatment with ultrasonic radiation, full carbonation (addition of CO 2 until the pH was stable for 2.5 h), liquid-to-solid (L/S) ratio, pH, leaching temperature and time. Full carbonation, pH and the L/S ratio were the main factors controlling the mobility of DOC in the bottom ash. Approximately 60 weight-% of the total organic carbon (TOC) in the bottom ash was available for leaching in aqueous solutions. The L/S ratio and pH mainly controlled the mobilization of DOC from the APC residue. About 93 weight-% of TOC in the APC residue was, however, not mobilized at all, which might be due to a high content of elemental carbon. Using the European standard EN 13 137 for determination of total organic carbon (TOC) in MSWI residues is inappropriate. The results might be biased due to elemental carbon. It is recommended to develop a TOC method distinguishing between organic and elemental carbon

  13. Reduction of phosphate ores by carbon: Part I. Process variables for design of rotary kiln system

    Science.gov (United States)

    Mu, Jacob; Leder, Frederic; Park, Won C.; Hard, Robert A.; Megy, Joseph; Reiss, Howard

    1986-12-01

    Feasibility is established for the reduction of phosphate ores in a rotary kiln, avoiding electric submerged arc furnace technology. This represents a totally new approach to phosphoric acid. Reduction rates of phosphate ore-silica mixtures by carbon in the temperature range of 1100 to 1500 °C under several CO partial pressures in nitrogen were measured in thermogravimetric analyzers. Parameters such as carbon and silica contents, particle and pellet sizes, and gas flow rate were also evaluated with various domestic and foreign phosphate ores. Furthermore, a variety of carbon sources such as subbituminous coals, bituminous coals, anthracite, petroleum coke, and metallurgical coke were tested as reducing agents. Thermodynamic considerations elucidate the temperature dependence of overall conversion as well as the role of excess silica in establishing equilibrium pressure. These findings provide the background for analysis of the kinetics of conversion in Part II of this work. These studies, in conjunction with a previously published work, indicate the importance of intergranular melt phases in the kinetics of otherwise solid state reactions.

  14. Complexation/encapsulation of green tea polyphenols in mixed calcium carbonate and phosphate micro-particles.

    Science.gov (United States)

    Elabbadi, Amal; Jeckelmann, Nicolas; Haefliger, Olivier P; Ouali, Lahoussine

    2011-01-01

    We used a double-jet mixer to encapsulate water-soluble polyphenols, green tea extract (GTE), with calcium-based inorganic materials. The device mixed calcium chloride solutions with a solution of carbonate and phosphate in the presence of a GTE solution, and formed micro-particles which capture the GTE molecules. The micro-particles were analysed by liquid chromatography coupled to tandem mass spectroscopy to determine the encapsulation yield and loading of the different GTE components. We established correlations between (1) the efficiency of the GTE encapsulation and the composition of the mixed anion solutions and (2) the protonation degree of the ions and the molar ratio of calcium cations and carbonate/phosphate anions. An optimal and reproducible GTE loading of about 40% with an encapsulation yield of 65% was observed for a carbonate/phosphate molar composition of 4 : 1. In addition, our experimental results showed that the process is selective and favours the encapsulation of gallated species which form stronger complexes with calcium cations.

  15. Utilization of Glyphosate as Phosphate Source: Biochemistry and Genetics of Bacterial Carbon-Phosphorus Lyase

    Science.gov (United States)

    Zechel, David L.; Jochimsen, Bjarne

    2014-01-01

    SUMMARY After several decades of use of glyphosate, the active ingredient in weed killers such as Roundup, in fields, forests, and gardens, the biochemical pathway of transformation of glyphosate phosphorus to a useful phosphorus source for microorganisms has been disclosed. Glyphosate is a member of a large group of chemicals, phosphonic acids or phosphonates, which are characterized by a carbon-phosphorus bond. This is in contrast to the general phosphorus compounds utilized and metabolized by microorganisms. Here phosphorus is found as phosphoric acid or phosphate ion, phosphoric acid esters, or phosphoric acid anhydrides. The latter compounds contain phosphorus that is bound only to oxygen. Hydrolytic, oxidative, and radical-based mechanisms for carbon-phosphorus bond cleavage have been described. This review deals with the radical-based mechanism employed by the carbon-phosphorus lyase of the carbon-phosphorus lyase pathway, which involves reactions for activation of phosphonate, carbon-phosphorus bond cleavage, and further chemical transformation before a useful phosphate ion is generated in a series of seven or eight enzyme-catalyzed reactions. The phn genes, encoding the enzymes for this pathway, are widespread among bacterial species. The processes are described with emphasis on glyphosate as a substrate. Additionally, the catabolism of glyphosate is intimately connected with that of aminomethylphosphonate, which is also treated in this review. Results of physiological and genetic analyses are combined with those of bioinformatics analyses. PMID:24600043

  16. Supported phosphate and carbonate salts for heterogeneous catalysis of triglycerides to fatty acid methyl esters

    Science.gov (United States)

    Britton, Stephanie Lynne

    Fatty acid methyl esters made from vegetable oil, or biodiesel, have been identified as a substitute for diesel derived from crude oil. Biodiesel is currently made using a homogeneous base catalyst to perform the transesterification of triglycerides with methanol to generate fatty acid methyl esters (FAME). The use of a homogeneous catalyst necessitates additional purification of the product and byproducts before sale, and the catalyst is consumed and discarded. The development of a heterogeneous basic catalyst for the production of FAME is desirable. Tribasic phosphate salts and dibasic carbonate salts are active for the production of FAME but generally operate as homogeneous catalysts. Supporting these phosphate and carbonate salts on mesoporous MCM-41, microporous silica gel, and nonporous a-alumina proved successful to greater or lesser degrees depending on the identity of the support and pretreatment of the support. Although these salts were supported and were active for the production of FAME from canola oil, they proved to be operating as homogeneous catalysts due to leaching of the active species off the surface of the support. Further investigation of the active species present in the tribasic phosphate catalysts identified the active support as orthophosphate, and NMR studies revealed the phosphorus to be present as orthophosphate and diphosphate in varying proportions in each catalyst. Evaluation of the acid-washing support pretreatment process revealed that the exposure of the support to acid plays a large role in the development of activity on the surface of the catalyst, but manipulation of these parameters did not prevent leaching of the active site off the surface of the catalyst. Alternate methods of support pretreatment were no more effective in preventing leaching. Tribasic phosphate supported on silica gel is not effective as a heterogeneous catalyst for FAME production from triglycerides because of the lack of stability of the phosphate on the

  17. The effect of organic ligands on the crystallinity of calcium phosphate

    Science.gov (United States)

    van der Houwen, Jacqueline A. M.; Cressey, Gordon; Cressey, Barbara A.; Valsami-Jones, Eugenia

    2003-03-01

    Calcium phosphate phases precipitated under critical supersaturation were identified and studied in detail using X-ray powder diffraction, electron probe microanalysis, infrared spectroscopy (IR) and transmission electron microscopy. These synthetic calcium phosphates formed by spontaneous precipitation at pH 7, 25°C and 0.1 M ionic strength (NaCl as the background electrolyte). The combination of several methods allowed detailed characterisation of the calcium phosphates. The purpose of the work was to assess the influence of carboxylate ligands, specifically acetate and citrate, on the quality of the calcium phosphate precipitate. All precipitates were identified as non-stoichiometric, calcium-deficient hydroxylapatites (HAPs), containing carbonate, HPO 42-, sodium and chloride impurities. No other phases were found to be present in any of the precipitates. The presence of citrate resulted in a decrease in crystal size and a higher degree of apatite lattice imperfection in the precipitated HAP. Furthermore, IR spectroscopy showed a higher amount of carbonate present in that HAP, compared with the ones formed in the control and acetate experiments. An additional absorption band, in the infrared spectrum of the HAP formed in the presence of citrate, was observed at 1570 cm -1; this is interpreted as carboxyl groups bound to HAP.

  18. Radiocarbon in marine dissolved organic carbon (DOC)

    NARCIS (Netherlands)

    Clercq, M. le; Plicht, J. van der; Meijer, H.A.J.; Baar, H.J.W. de

    Dissolved Organic Carbon (DOC) plays an important role in the ecology and carbon cycle in the ocean. Analytical problems with concentration and isotope ratio measurements have hindered its study. We have constructed a new analytical method based on supercritical oxidation for the determination of

  19. Organic carbon spiralling in stream ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Newbold, J D; Mulholland, P J; Elwood, J W; O' Neill, R V

    1982-01-01

    The term spiralling has been used to describe the combined processes of cycling and longitudinal transport in streams. As a measure or organic carbon spiralling, we introduced organic carbon turnover length, S, defined as the average or expected downstream distance travelled by a carbon atom between its entry or fixation in the stream and its oxidation. Using a simple model for organic carbon dynamics in a stream, we show that S is closely related to fisher and Likens' ecosystem efficiency. Unlike efficiency, however, S is independent of the length of the study reach, and values of S determined in streams of differing lengths can be compared. Using data from three different streams, we found the relationship between S and efficiency to agree closely with the model prediction. Hypotheses of stream functioning are discussed in the context of organic carbeon spiralling theory.

  20. Performance of flexible capacitors based on polypyrrole/carbon fiber electrochemically prepared from various phosphate electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wei; Han, Gaoyi, E-mail: han_gaoyis@sxu.edu.cn; Chang, Yunzhen; Li, Miaoyu; Xiao, Yaoming, E-mail: ymxiao@sxu.edu.cn; Zhou, Haihan; Zhang, Ying; Li, Yanping

    2016-11-30

    Highlights: • PPy/CFs have been fabricated by electrodepositing polypyrrole on carbon fibers. • The electrolytes in deposition solution have effect on PPy/CFs’ capacitive behavior. • Cells of PPy/CFs obtained from NaH{sub 2}PO{sub 4} electrolyte has good stability in PVA/H{sub 3}PO{sub 4}. - Abstract: In order to investigate the influence of electrolytes in electro-deposition solution on the capacitive properties of polypyrrole (PPy), we have chosen phosphoric acid, phosphate, hydrogen phosphate and dihydrogen phosphate as electrolyte in deposition solution respectively and electrochemically deposited PPy on carbon fibers (CFs) via galvanostatic method. The morphologies of the PPy/CFs samples have been characterized by scanning electron microscope. The specific capacitance of PPy/CFs samples has been evaluated in different electrolytes through three-electrode test system. The assembled flexible capacitors by using PPy/CFs as electrodes and H{sub 3}PO{sub 4}/polyvinyl alcohol as gel electrolyte have been systematically measured by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. The results show that the electrochemical capacitors based on PPy/CFs prepared from deposition solution containing NaH{sub 2}PO{sub 4}·2H{sub 2}O electrolyte exhibit higher specific capacitance, flexibility and excellent stability (retaining 96.8% of initial capacitance after 13,000 cycles), and that three cells connected in series can power a light-emitting diode.

  1. Positive feedback between acidification and organic phosphate mineralization in the rhizosphere of maize (Zea mays L.).

    NARCIS (Netherlands)

    Ding, X.; Fu, L.; Liu, C.; Chen, F.; Hoffland, E.; Shen, J.; Zhang, F.; Feng, G.

    2011-01-01

    Abstract To test the hypothesis that rhizosphere acidification would enhance the hydrolyzation of organic phosphates by increasing phosphatase activity. A Petri dish experiment with sterile agar and a pot experiment with a low P soil were used. In the Petri dish experiment, roots of each plant were

  2. Fabrication of carbonate apatite block based on internal dissolution-precipitation reaction of dicalcium phosphate and calcium carbonate.

    Science.gov (United States)

    Daitou, Fumikazu; Maruta, Michito; Kawachi, Giichiro; Tsuru, Kanji; Matsuya, Shigeki; Terada, Yoshihiro; Ishikawa, Kunio

    2010-05-01

    In this study, we investigated a novel method for fabrication of carbonate apatite block without ionic movement between precursor and solution by using precursor that includes all constituent ions of carbonate apatite. A powder mixture prepared from dicalcium phosphate anhydrous and calcite at appropriate Ca/P ratios (1.5, 1.67, and 1.8) was used as starting material. For preparation of specimens, the slurry made from the powder mixture and distilled water was packed in a split stainless steel mold and heat - treated, ranging from 60 degrees C to 100 degrees C up to 48 hours at 100% humidity. It appeared that carbonate apatite could be obtained above 70 degrees C and monophasic carbonate apatite could be obtained from the powder mixture at Ca/P ratio of 1.67. Carbonate content of the specimen was about 5-7%. Diametral tensile strength of the carbonate apatite blocks slightly decreased with increasing treatment temperature. The decrease in diametral tensile strength is thought to be related to the crystal size of the carbonate apatite formed.

  3. Physicochemical characteristics and sorption capacities of heavy metal ions of activated carbons derived by activation with different alkyl phosphate triesters

    Science.gov (United States)

    Wang, Jing; Liu, Hai; Yang, Shaokun; Zhang, Jian; Zhang, Chenglu; Wu, Haiming

    2014-10-01

    Five alkyl phosphate triesters (APTEs), including trimethyl phosphate (TMP), triethyl phosphate (TEP), triisopropyl phosphate (TPP), tributyl phosphate (TBP) and trioctyl phosphate (TOP), were used as activating agents for preparing activated carbons (AC-APTEs) with high surface acidity and metal ion sorption capacity. N2 adsorption/desorption isotherms, surface morphologies, elemental compositions, results of Boehm's titration and sorption capacities of heavy metal ions of the carbons were investigated. AC-APTEs contained much more acidic groups and exhibited much less surface area (phosphoric acid activation. For the AC-APTEs, AC-TOP had the highest surface area (488 m2/g), AC-TMP showed the highest yield (41.1%), and AC-TBP possessed the highest acidic groups (2.695 mmol/g), oxygen content (47.0%) and metal ion sorption capacities (40.1 mg/g for Ni(II) and 53.5 mg/g for Cd(II)). For the carbons, AC-APTEs showed much larger Ni(II) and Cd(II) sorption capacities than AC-PPA, except AC-TPP. The differences of the carbons in the physicochemical and sorption properties suggested surface chemistry of the carbons was the main factor influencing their sorption capacities whereas the pore structure played a secondary role.

  4. Worldwide organic soil carbon and nitrogen data

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-09-01

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

  5. Organic Carbon Storage in China's Urban Areas

    Science.gov (United States)

    Zhao, Shuqing; Zhu, Chao; Zhou, Decheng; Huang, Dian; Werner, Jeremy

    2013-01-01

    China has been experiencing rapid urbanization in parallel with its economic boom over the past three decades. To date, the organic carbon storage in China's urban areas has not been quantified. Here, using data compiled from literature review and statistical yearbooks, we estimated that total carbon storage in China's urban areas was 577±60 Tg C (1 Tg  = 1012 g) in 2006. Soil was the largest contributor to total carbon storage (56%), followed by buildings (36%), and vegetation (7%), while carbon storage in humans was relatively small (1%). The carbon density in China's urban areas was 17.1±1.8 kg C m−2, about two times the national average of all lands. The most sensitive variable in estimating urban carbon storage was urban area. Examining urban carbon storages over a wide range of spatial extents in China and in the United States, we found a strong linear relationship between total urban carbon storage and total urban area, with a specific urban carbon storage of 16 Tg C for every 1,000 km2 urban area. This value might be useful for estimating urban carbon storage at regional to global scales. Our results also showed that the fraction of carbon storage in urban green spaces was still much lower in China relative to western countries, suggesting a great potential to mitigate climate change through urban greening and green spaces management in China. PMID:23991014

  6. [Organic carbon and carbon mineralization characteristics in nature forestry soil].

    Science.gov (United States)

    Yang, Tian; Dai, Wei; An, Xiao-Juan; Pang, Huan; Zou, Jian-Mei; Zhang, Rui

    2014-03-01

    Through field investigation and indoor analysis, the organic carbon content and organic carbon mineralization characteristics of six kinds of natural forest soil were studied, including the pine forests, evergreen broad-leaved forest, deciduous broad-leaved forest, mixed needle leaf and Korean pine and Chinese pine forest. The results showed that the organic carbon content in the forest soil showed trends of gradual decrease with the increase of soil depth; Double exponential equation fitted well with the organic carbon mineralization process in natural forest soil, accurately reflecting the mineralization reaction characteristics of the natural forest soil. Natural forest soil in each layer had the same mineralization reaction trend, but different intensity. Among them, the reaction intensity in the 0-10 cm soil of the Korean pine forest was the highest, and the intensities of mineralization reaction in its lower layers were also significantly higher than those in the same layers of other natural forest soil; comparison of soil mineralization characteristics of the deciduous broad-leaved forest and coniferous and broad-leaved mixed forest found that the differences of litter species had a relatively strong impact on the active organic carbon content in soil, leading to different characteristics of mineralization reaction.

  7. Nanoparticle-based, organic receptor coupled fluorescent chemosensors for the determination of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Navneet, E-mail: navneetkaur@pu.ac.in [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Kaur, Simanpreet; Kaur, Amanpreet [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Saluja, Preeti; Sharma, Hemant [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India); Saini, Anu; Dhariwal, Nisha [Centre for Nanoscience and Nanotechnology (UIEAST), Panjab University, Chandigarh 160014 (India); Singh, Ajnesh; Singh, Narinder [Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001 (India)

    2014-01-15

    The sensors have been developed using silver nanoparticles coated with organic ligands and are fully characterized with spectroscopic methods. The energy-dispersive X-ray (EDX) analysis revealed the presence of organic receptors on the surface of metal nanoparticles. These chemosensors were tested against a range of biological and environmentally relevant cations in the HEPES buffered DMSO/H{sub 2}O (8:2, v/v) solvent system. The fluorescence intensity of these chemosensors was quenched upon coordination with open shell metal ions such as Cu{sup 2+}/Fe{sup 3+}. Anion recognition properties of the corresponding metal complexes have been studied and the original fluorescence intensity of sensors was restored upon addition of phosphate (0–20 µM). Thus, a highly selective chemosensor has been devised for the micromolar estimation of phosphate in semi-aqueous medium. -- Highlights: • The silver nanoparticles have been decorated with organic receptors for chemosensor applications. • The sensor properties are developed for the estimation of phosphate anion. • Thus the sensor relies on the cation displacement assay. • The phosphate sensing event displays the “ON–OFF–ON” mode of switching in sensor.

  8. Ion chromatographic determination of Di-n-butyl phosphate in degraded organic solvent

    International Nuclear Information System (INIS)

    Velavendan, P.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

    2011-01-01

    In the present work a method for the determination of Di-n-butyl phosphate in organic streams using Ion Chromatography technique is developed and described here. The method involves the separation of Di-n-butyl phosphate (DBP) from 30% TBP-NPH (Tri-n-butylphosphate diluted in Normal Paraffin Hydrocarbon) and uranium/nitric acid matrix by an extraction of DBP in alkaline medium and subsequent ion-exchange separation in ion chromatography column followed by suppressed conductivity detection. Direct determination of DBP in lean/loaded organic solvent will lead to in accurate determination of DBP due to organic interference. DBP is quantified to lower limit of 1 ppm with 3% RSD. The results obtained with ion chromatographic technique are compared with those obtained by standard gas chromatographic technique. The developed method is much faster and total analysis can be completed within two hours. (author)

  9. Effect of carbonate and phosphate ratios on the transformation of calcium orthophosphates

    Energy Technology Data Exchange (ETDEWEB)

    Eliassi, Mohammad Daoud, E-mail: eliassi2007@gmail.com [Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Zhao, Wei [State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling 712100 (China); Tan, Wen Feng, E-mail: wenfeng.tan@hotmail.com [Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China)

    2014-07-01

    Graphical abstract: Complexes among phosphate, carbonate and calcium have been prepared via a facile hydrothermal route. The synthesized product at the low (0.15) and the high (1.8) molar ratio of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} is calcium phosphate hydrate and hydroxylapatite (HAp), respectively. Molar ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} are effective on the reduction of carbonate activity during the crystallization of HAp. - Highlights: • Formation of different complexes from CO{sub 3}{sup 2−}, PO{sub 4}{sup 3−} and Ca{sup 2+} solutions at 60 °C. • Molar ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2} cause changes in phase and size of synthesized products. • Addition of PO{sub 4}{sup 3} inhibited the activity of CO{sub 3}{sup 2−} during bound with Ca{sup 2+}. • The phase transformation was completed, when CO{sub 3}{sup 2−} peaks disappeared in FTIR. • PO{sub 4}{sup 3−}, CO{sub 3}{sup 2−} and Ca{sup 2+} distributed heterogeneously on the surface of precipitation. - Abstract: Complexes among phosphate, carbonate and calcium have been synthesized by a designed hydrothermal method. Effects of carbonate and phosphate ratios on the transformation of calcium-orthophosphates were investigated. With X-ray diffraction measurement the synthesized product at the low (0.15) and the high (1.8) molar ratio of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} is calcium phosphate hydrate at pH 9.0, and hydroxylapatite (HAp) at pH 8.0, respectively. Fourier transform infrared spectroscopy of product at the high ratio (1.8) of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} shows that the CO{sub 3}{sup 2−} peaks disappear, and the strong peaks at 1412 and 1460 cm{sup −1} are assigned to the vibrations of PO{sub 4}{sup 3−} in HAp. {sup 31}P nuclear magnetic resonance spectra of products at the low (0.15–0.6) to the high (1.2–1.8) ratios of PO{sub 4}{sup 3−}/CO{sub 3}{sup 2−} are obtained at 2.9 and 2.7 ppm, respectively. Molar ratios of PO

  10. Temperature dependence of photodegradation of dissolved organic matter to dissolved inorganic carbon and particulate organic carbon

    Czech Academy of Sciences Publication Activity Database

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

    2015-01-01

    Roč. 10, č. 6 (2015), e0128884 E-ISSN 1932-6203 R&D Projects: GA ČR(CZ) GAP503/12/0781; GA ČR(CZ) GA15-09721S Institutional support: RVO:60077344 Keywords : dissolved organic carbon * particulate organic carbon * photodegradation * temperature Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.057, year: 2015

  11. Dissolution and storage stability of nanostructured calcium carbonates and phosphates for nutrition

    Energy Technology Data Exchange (ETDEWEB)

    Posavec, Lidija; Knijnenburg, Jesper T. N., E-mail: jesper.knijnenburg@alumni.ethz.ch; Hilty, Florentine M. [ETH Zurich, Human Nutrition Laboratory, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology (Switzerland); Krumeich, Frank; Pratsinis, Sotiris E. [ETH Zurich, Particle Technology Laboratory, Institute of Process Engineering, Department of Mechanical and Process Engineering (Switzerland); Zimmermann, Michael B. [ETH Zurich, Human Nutrition Laboratory, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology (Switzerland)

    2016-10-15

    Rapid calcium (Ca) dissolution from nanostructured Ca phosphate and carbonate (CaCO{sub 3}) powders may allow them to be absorbed in much higher fraction in humans. Nanosized Ca phosphate and CaCO{sub 3} made by flame-assisted spray pyrolysis were characterized by nitrogen adsorption, X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy. As-prepared nanopowders contained both CaCO{sub 3} and CaO, but storing them under ambient conditions over 130 days resulted in a complete transformation into CaCO{sub 3}, with an increase in both crystal and particle sizes. The small particle size could be stabilized against such aging by cation (Mg, Zn, Sr) and anion (P) doping, with P and Mg being most effective. Calcium phosphate nanopowders made at Ca:P ≤ 1.5 were XRD amorphous and contained γ-Ca{sub 2}P{sub 2}O{sub 7} with increasing hydroxyapatite content at higher Ca:P. Aging of powders with Ca:P = 1.0 and 1.5 for over 500 days gradually increased particle size (but less than for CaCO{sub 3}) without a change in phase composition or crystallinity. In 0.01 M H{sub 3}PO{sub 4} calcium phosphate nanopowders dissolved ≈4 times more Ca than micronsized compounds and about twice more Ca than CaCO{sub 3} nanopowders, confirming that nanosizing and/or amorphous structuring sharply increases Ca powder dissolution. Because higher Ca solubility in vitro generally leads to greater absorption in vivo, these novel FASP-made Ca nanostructured compounds may prove useful for nutrition applications, including supplementation and/or food fortification.

  12. Dissolution and storage stability of nanostructured calcium carbonates and phosphates for nutrition

    Science.gov (United States)

    Posavec, Lidija; Knijnenburg, Jesper T. N.; Hilty, Florentine M.; Krumeich, Frank; Pratsinis, Sotiris E.; Zimmermann, Michael B.

    2016-10-01

    Rapid calcium (Ca) dissolution from nanostructured Ca phosphate and carbonate (CaCO3) powders may allow them to be absorbed in much higher fraction in humans. Nanosized Ca phosphate and CaCO3 made by flame-assisted spray pyrolysis were characterized by nitrogen adsorption, X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy. As-prepared nanopowders contained both CaCO3 and CaO, but storing them under ambient conditions over 130 days resulted in a complete transformation into CaCO3, with an increase in both crystal and particle sizes. The small particle size could be stabilized against such aging by cation (Mg, Zn, Sr) and anion (P) doping, with P and Mg being most effective. Calcium phosphate nanopowders made at Ca:P ≤ 1.5 were XRD amorphous and contained γ-Ca2P2O7 with increasing hydroxyapatite content at higher Ca:P. Aging of powders with Ca:P = 1.0 and 1.5 for over 500 days gradually increased particle size (but less than for CaCO3) without a change in phase composition or crystallinity. In 0.01 M H3PO4 calcium phosphate nanopowders dissolved ≈4 times more Ca than micronsized compounds and about twice more Ca than CaCO3 nanopowders, confirming that nanosizing and/or amorphous structuring sharply increases Ca powder dissolution. Because higher Ca solubility in vitro generally leads to greater absorption in vivo, these novel FASP-made Ca nanostructured compounds may prove useful for nutrition applications, including supplementation and/or food fortification.

  13. Dissolution and storage stability of nanostructured calcium carbonates and phosphates for nutrition

    International Nuclear Information System (INIS)

    Posavec, Lidija; Knijnenburg, Jesper T. N.; Hilty, Florentine M.; Krumeich, Frank; Pratsinis, Sotiris E.; Zimmermann, Michael B.

    2016-01-01

    Rapid calcium (Ca) dissolution from nanostructured Ca phosphate and carbonate (CaCO 3 ) powders may allow them to be absorbed in much higher fraction in humans. Nanosized Ca phosphate and CaCO 3 made by flame-assisted spray pyrolysis were characterized by nitrogen adsorption, X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy. As-prepared nanopowders contained both CaCO 3 and CaO, but storing them under ambient conditions over 130 days resulted in a complete transformation into CaCO 3 , with an increase in both crystal and particle sizes. The small particle size could be stabilized against such aging by cation (Mg, Zn, Sr) and anion (P) doping, with P and Mg being most effective. Calcium phosphate nanopowders made at Ca:P ≤ 1.5 were XRD amorphous and contained γ-Ca 2 P 2 O 7 with increasing hydroxyapatite content at higher Ca:P. Aging of powders with Ca:P = 1.0 and 1.5 for over 500 days gradually increased particle size (but less than for CaCO 3 ) without a change in phase composition or crystallinity. In 0.01 M H 3 PO 4 calcium phosphate nanopowders dissolved ≈4 times more Ca than micronsized compounds and about twice more Ca than CaCO 3 nanopowders, confirming that nanosizing and/or amorphous structuring sharply increases Ca powder dissolution. Because higher Ca solubility in vitro generally leads to greater absorption in vivo, these novel FASP-made Ca nanostructured compounds may prove useful for nutrition applications, including supplementation and/or food fortification.

  14. Effect of altitude on oxygen binding by hemoglobin and on organic phosphate levels

    Science.gov (United States)

    Lenfant, Claude; Torrance, John; English, Eugenia; Finch, Clement A.; Reynafarje, Cesar; Ramos, Jose; Faura, Jose

    1968-01-01

    The relationship between oxygen dissociation and 2,3-diphosphoglycerate (2,3-DPG) in the red cell has been studied in subjects moving from low to high altitude and vice versa. Within 24 hr following the change in altitude there was a change in hemoglobin affinity for oxygen; this modification therefore represents an important rapid adaptive mechanism to anoxia. A parallel change occurred in the organic phosphate content of the red cell. While this study does not provide direct evidence of a cause-effect relationship, the data strongly suggest that with anoxia, the observed rise in organic phosphate content of the red cell is responsible for increased availability of oxygen to tissues. Images PMID:5725278

  15. Organic resources and earthworms affect phosphorus availability to sorghum after phosphate rock addition in semi-arid West Africa

    NARCIS (Netherlands)

    Ouédraogo, E.; Brussaard, L.; Mando, A.; Stroosnijder, L.

    2005-01-01

    A field experiment was laid out in Burkina Faso (West Africa) on an Eutric Cambisol to investigate the interaction of organic resource quality and phosphate rock on crop yield and to assess the contribution of earthworms (Millsonia inermis Michaelsen) to P availability after phosphate rock

  16. Fertilization increases paddy soil organic carbon density*

    Science.gov (United States)

    Wang, Shao-xian; Liang, Xin-qiang; Luo, Qi-xiang; Fan, Fang; Chen, Ying-xu; Li, Zu-zhang; Sun, Huo-xi; Dai, Tian-fang; Wan, Jun-nan; Li, Xiao-jun

    2012-01-01

    Field experiments provide an opportunity to study the effects of fertilization on soil organic carbon (SOC) sequestration. We sampled soils from a long-term (25 years) paddy experiment in subtropical China. The experiment included eight treatments: (1) check, (2) PK, (3) NP, (4) NK, (5) NPK, (6) 7F:3M (N, P, K inorganic fertilizers+30% organic N), (7) 5F:5M (N, P, K inorganic fertilizers+50% organic N), (8) 3F:7M (N, P, K inorganic fertilizers+70% organic N). Fertilization increased SOC content in the plow layers compared to the non-fertilized check treatment. The SOC density in the top 100 cm of soil ranged from 73.12 to 91.36 Mg/ha. The SOC densities of all fertilizer treatments were greater than that of the check. Those treatments that combined inorganic fertilizers and organic amendments had greater SOC densities than those receiving only inorganic fertilizers. The SOC density was closely correlated to the sum of the soil carbon converted from organic amendments and rice residues. Carbon sequestration in paddy soils could be achieved by balanced and combined fertilization. Fertilization combining both inorganic fertilizers and organic amendments is an effective sustainable practice to sequestrate SOC. PMID:22467369

  17. Fertilization increases paddy soil organic carbon density.

    Science.gov (United States)

    Wang, Shao-xian; Liang, Xin-qiang; Luo, Qi-xiang; Fan, Fang; Chen, Ying-xu; Li, Zu-zhang; Sun, Huo-xi; Dai, Tian-fang; Wan, Jun-nan; Li, Xiao-jun

    2012-04-01

    Field experiments provide an opportunity to study the effects of fertilization on soil organic carbon (SOC) sequestration. We sampled soils from a long-term (25 years) paddy experiment in subtropical China. The experiment included eight treatments: (1) check, (2) PK, (3) NP, (4) NK, (5) NPK, (6) 7F:3M (N, P, K inorganic fertilizers+30% organic N), (7) 5F:5M (N, P, K inorganic fertilizers+50% organic N), (8) 3F:7M (N, P, K inorganic fertilizers+70% organic N). Fertilization increased SOC content in the plow layers compared to the non-fertilized check treatment. The SOC density in the top 100 cm of soil ranged from 73.12 to 91.36 Mg/ha. The SOC densities of all fertilizer treatments were greater than that of the check. Those treatments that combined inorganic fertilizers and organic amendments had greater SOC densities than those receiving only inorganic fertilizers. The SOC density was closely correlated to the sum of the soil carbon converted from organic amendments and rice residues. Carbon sequestration in paddy soils could be achieved by balanced and combined fertilization. Fertilization combining both inorganic fertilizers and organic amendments is an effective sustainable practice to sequestrate SOC.

  18. Relationship between Organic Carbon Runoff to River and Land Cover

    Science.gov (United States)

    Kim, G. S.; Lee, S. G.; Lim, C. H.; Lee, W.; Yoo, S.; Kim, S. J.; Heo, S.; Lee, W. K.

    2017-12-01

    Carbon is an important unit in understanding the ecosystem and energy circulation. Each ecosystem, land, water, and atmosphere, is interconnected through the exchange of energy and organic carbon. In the rivers, primary producers utilize the organic carbon from the land. Understanding the organic carbon uptake into the river is important for understanding the mechanism of river ecosystems. The main organic carbon source of the river is land. However, it is difficult to observe the amount of organic carbon runoff to the river. Therefore, an indirect method should be used to estimate the amount of organic carbon runoff to the river. The organic carbon inflow is caused by the runoff of organic carbon dissolved in water or the inflow of organic carbon particles by soil loss. Therefore, the hydrological model was used to estimate organic carbon runoff through the flow of water. The land cover correlates with soil respiration, soil loss, and so on, and the organic carbon runoff coefficient will be estimated to the river by land cover. Using the organic carbon concentration from water quality data observed at each point in the river, we estimate the amount of organic carbon released from the land. The reason is that the runoff from the watershed converges into the rivers in the watershed, the watershed simulation is conducted based on the water quality data observation point. This defines a watershed that affects organic carbon observation sites. The flow rate of each watershed is calculated by the SWAT (Soil and Water Assessment Tool), and the total organic carbon runoff is calculated by using flow rate and organic carbon concentration. This is compared with the factors related to the amount of organic carbon such as land cover, soil loss, and soil organic carbon, and spatial analysis is carried out to estimate the organic carbon runoff coefficient per land cover.

  19. Zirconium-based metal organic frameworks: Highly selective adsorbents for removal of phosphate from water and urine

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Kun-Yi Andrew, E-mail: linky@nchu.edu.tw [Department of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung, Taiwan (China); Chen, Shen-Yi [Department of Environmental Engineering, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung, Taiwan (China); Jochems, Andrew P. [New Mexico Bureau of Geology & Mineral Resources and New Mexico Institute of Mining & Technology, Socorro, NM (United States)

    2015-06-15

    Phosphate is one of the most concerning compounds in wastewater streams and a main nutrient that causes eutrophication. To eliminate the phosphate pollution, Metal Organic Frameworks (MOFs) are proposed in this study as adsorbents to remove phosphate from water. The zirconium-based MOF, UiO-66, was selected as representative MOF given its exceptional stability in water. To investigate the effect of an amine functional group, UiO-66-NH2 was also prepared using an amine-substituted ligand. The adsorption kinetics and isotherm reveal that UiO-66-NH2 exhibited higher adsorption capacities than UiO-66 possibly due to the amine group. However, the interaction between phosphate and zirconium sites of UiO MOFs might be the primary factor accounting for the phosphate adsorption to UiO MOFs. UiO MOFs also exhibited a high selectivity towards phosphate over other anions such as bromate, nitrite and nitrate. Furthermore, UiO MOFs were found to adsorb phosphate and to completely remove diluted phosphate in urine. We also found that UiO MOFs could be easily regenerated and re-used for phosphate adsorption. These findings suggest that UiO MOFs can be effective and selective adsorbents to remove phosphate from water as well as urine. - Highlights: • UiO-66 as the first type of MOFs was used to remove phosphate from water and urine. • The amine group in UiO MOFs was found to enhance the phosphate adsorption. • UiO-66 exhibited a high adsorption selectivity towards phosphate over other anions. • UiO-66 could be easily regenerated and re-used with 85% regeneration efficiency.

  20. Calcium carbonate phosphate binding ion exchange filtration and accelerated denitrification improve public health standards and combat eutrophication in aquatic ecosystems.

    Science.gov (United States)

    Yanamadala, Vijay

    2005-01-01

    Cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. The process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. Especially in Madrona Marsh, one of the last remaining vernal marshes in the greater Los Angeles area, California, cultural eutrophication has become a major problem. In this study, calcium carbonate was found to be an excellent phosphate binder, reducing up to 70% of the phosphates in a given sample of water, and it posed relatively negligent ecological repercussions. This study involved the testing of this principle in both the laboratory and the real ecosystem. A calcium carbonate lacing procedure was first carried out to determine its efficacy in Madrona Marsh. Through this, ammonia was found to interfere with the solubility of calcium carbonate and therefore to be a hindrance to the reduction of phosphate. Therefore, various approaches for reduction of ammonia were tested, including aeration, use of fiber growth media, and plants, mainly Caulerpa verticellata, chosen for it hardiness, primarily in an attempt to increase population of Nitrobacter and Nitrosomonas. All were successful in moderately reducing ammonia levels. In addition, soil sampling, sediment analysis, microscopic plant analysis, microorganism and macroinvertebrate identification, and rate law formulations were conducted. The effect of phosphate and ammonia reduction on the populations of enterobacteria was also an important focus of this experiment. Varying concentrations of phosphate, ammonia, and calcium carbonate in conjunction with phosphate were tested in Madrona Marsh to determine their effects on the populations of enteropathogens on nonspecific blood agar, MacConkey agar, and

  1. Unusual carbon partitioning during phosphate deficiency in celery, a mannitol-synthesizing species

    Energy Technology Data Exchange (ETDEWEB)

    Tyson, R.H.; Loescher, W.H. (Washington State Univ., Pullman (USA))

    1989-04-01

    Mannitol and sucrose are the main photosynthetic products and translocated carbon compounds in celery (Apium graveolens L.). Carbon partitioning was studied in greenhouse-grown celery plants supplied with a nutrient solution containing or lacking phosphate (P). P-deficient plants developed new leaves at about the same rate as control plants, but showed greatly reduced growth of leaves and petioles; root growth was apparently unaffected. P-deficient leaves contained less mannitol and more sucrose than control leaves. Starch content increased with P-deficiency only in mature (the most photosynthetically-active) leaves, and then amounted to less than 10 mg/g fresh weight. Similarly, when {sup 14}CO{sub 2} was supplied to intact plants, P-deficient leaves contained less label in mannitol and more in sucrose than did control leaves; labeling of starch changed little. The P-status of celery leaves apparently affects the partitioning of carbon between mannitol and sucrose more than it affects starch accumulation. This is in marked contrast to the large increase in starch content commonly observed during P-deficiency in species that produce and translocate predominantly sucrose.

  2. Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction.

    Science.gov (United States)

    Combes, C; Bareille, R; Rey, C

    2006-11-01

    The feasibility of making calcium carbonate-calcium phosphate (CaCO(3)-CaP) mixed cements, comprising at least 40% (w/w) CaCO(3) in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline CaCO(3) phases with metastable amorphous or crystalline CaP powders in aqueous medium. The cements set within at most 1 h at 37 degrees C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the metastable CaP phase with part or almost all of the metastable CaCO(3) phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO(3) with a higher solubility than that of the apatite formed in the well-developed CaP cements might be of interest to increase resorption rates in biomedical cement and favors its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO(3)-CaP mixed cement compositions.

  3. Input related microbial carbon dynamic of soil organic matter in particle size fractions

    Science.gov (United States)

    Gude, A.; Kandeler, E.; Gleixner, G.

    2012-04-01

    This paper investigated the flow of carbon into different groups of soil microorganisms isolated from different particle size fractions. Two agricultural sites of contrasting organic matter input were compared. Both soils had been submitted to vegetation change from C3 (Rye/Wheat) to C4 (Maize) plants, 25 and 45 years ago. Soil carbon was separated into one fast-degrading particulate organic matter fraction (POM) and one slow-degrading organo-mineral fraction (OMF). The structure of the soil microbial community were investigated using phospholipid fatty acids (PLFA), and turnover of single PLFAs was calculated from the changes in their 13C content. Soil enzyme activities involved in the degradation of carbohydrates was determined using fluorogenic MUF (methyl-umbelliferryl phosphate) substrates. We found that fresh organic matter input drives soil organic matter dynamic. Higher annual input of fresh organic matter resulted in a higher amount of fungal biomass in the POM-fraction and shorter mean residence times. Fungal activity therefore seems essential for the decomposition and incorporation of organic matter input into the soil. As a consequence, limited litter input changed especially the fungal community favouring arbuscular mycorrhizal fungi. Altogether, supply and availability of fresh plant carbon changed the distribution of microbial biomass, the microbial community structure and enzyme activities and resulted in different priming of soil organic matter. Most interestingly we found that only at low input the OMF fraction had significantly higher calculated MRT for Gram-positive and Gram-negative bacteria suggesting high recycling of soil carbon or the use of other carbon sources. But on average all microbial groups had nearly similar carbon uptake rates in all fractions and both soils, which contrasted the turnover times of bulk carbon. Hereby the microbial carbon turnover was always faster than the soil organic carbon turnover and higher carbon input

  4. Effect of pH and phosphate on calcium carbonate polymorphs precipitated at near-freezing temperature

    NARCIS (Netherlands)

    Hu, Yu-Bin; Wolthers, Mariëtte; Wolf-Gladrow, Dieter A.; Nehrke, Gernot

    2015-01-01

    The effects of pH and phosphate on the precipitation of calcium carbonate polymorphs from aqueous solution were investigated. Experiments were carried out at near-freezing temperature and two different pH conditions (pH 13.4 and 9.0). At each pH condition, solutions having different concentrations

  5. Dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate-hydrogen peroxide

    International Nuclear Information System (INIS)

    Kanekar, A.S.; Pathak, P.N.; Mohapatra, P.K.; Manchanda, V.K.

    2009-01-01

    Direct dissolution of uranium dioxide in supercritical carbon dioxide modified with tri-n-butyl phosphate (TBP) has been attempted. The effects of TBP concentration and pressure on the extraction of uranium have been studied. Addition of hydrogen peroxide in the modifier enhances the dissolution/extraction of uranium. (author)

  6. Hydrocortisone and Vitamin D3 stimulation of 32Psub(i)-phosphate accumulation by organ-cultured chick embryo duodenum

    International Nuclear Information System (INIS)

    Corradino, R.A.

    1979-01-01

    Either vitamin D 3 (or 1 α,25-(OH) 2 -D 3 ) or hydrocortisone (HC) stimulated phosphate accumulation by organ-cultured embryonic chick duodenum. In combination, these two steroids stimulated phosphate uptake synergistically. Phosphate accumulation appeared to be independent of other vitamin D 3 -stimulated processes: CaBP concentration, cAMP concentration, or alkaline phosphataseactivity. L-phenylalanine, a reported alkaline phosphate inhibitor, when added to the culture medium progressively inhibited either D 3 - or HC-stimulated phosphate uptake subsequent to culture, but did not inhibit the synergistic action under these conditions L-phenylalanine had no consistent effect on alkaline phosphotase activity but unexpectedly, greatly inhibited vitamin D 3 - stimulated CaBP concentration, but only in the absence of HC. Some limited suggestion of an intestinal phosphoprotein sensitve to either vitamin D 3 or HC was observed. (orig.) [de

  7. Organic carbon dynamics in mangrove ecosystems: a review

    NARCIS (Netherlands)

    Kristensen, E.; Bouillon, S.; Dittmar, T.; Marchand, C.

    2008-01-01

    Our current knowledge on production, composition, transport, pathways and transformations of organic carbon in tropical mangrove environments is reviewed and discussed. Organic carbon entering mangrove foodwebs is either produced autochthonously or imported by tides and/or rivers. Mangrove litter

  8. Method for obtaining more precise measures of excreted organic carbon

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    A new method for concentrating and measuring excreted organic carbon by lyophilization and scintillation counting is efficient, improves measurable radioactivity, and increases precision for estimates of organic carbon excreted by phytoplankton and macrophytes

  9. Distribution of organic carbon in sediments from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; Mascarenhas, A.; PrakashBabu, C.

    Many earlier studies on the distribution of organic carbon in the Arabian Sea, sediments have projected contradictory opinions on the factors favouring accumulation and preservation of organic carbon in the Arabian Sea. An attempt is made...

  10. Effects of Jerusalem Artichoke Powder and Sodium Carbonate as Phosphate Replacers on the Quality Characteristics of Emulsified Chicken Meatballs.

    Science.gov (United States)

    Öztürk, Burcu; Serdaroğlu, Meltem

    2018-02-01

    Today incorporation of natural ingredients as inorganic phosphate replacers has come into prominence as a novel research topic due to health concerns about phosphates. In this study, we aimed to investigate the quality of emulsified chicken meatballs produced with Jerusalem artichoke powder (JAP), either alone or in combination with sodium carbonate (SC) as sodium tripolyphosphate (STPP) replacers. The results showed that naturally dried JAP showed favorable technological properties in terms of water-oil binding and gelling. Emulsion batters formulated with JAP-SC mixture showed lower jelly and fat separation, higher water-holding capacity and higher emulsion stability than control samples with STPP. In final product, incorporation of JAP-SC mixture increased moisture and reduced lipid and energy values, and kept the pH value similar to control. Added JAP lead to increments in b* values whereas decreases L* values. Cook yield was similar to control in phosphate-free samples formulated with JAP-SC mix. Either low or medium ratios of JAP in combination with SC managed to protect most of the sensory parameters, while sensory scores tend to decrease in samples containing high levels of JAP. Addition of JAP to formulations presented samples that have equivalent behavior to phosphates in terms of lipid oxidation. In conclusion, our study confirms that utilization of JAP in combination with SC had promising effects as phosphate replacers by presenting natural solutions and providing equivalent quality to standard phosphate containing products.

  11. The Path of Carbon in Photosynthesis XIX. The Identification of Sucrose Phosphate in Sugar Beet Leaves

    Science.gov (United States)

    Buchanan, J. G.

    1952-09-01

    The recognition and characterization of a sucrose phosphate as an intermediate in sucrose by synthesis by green plants is described. A tentative structure for this phosphate is proposed and its mode of formation suggested.

  12. Application of phosphating techniques to aluminium and carbon steel surfaces using nitro guanidine as oxidizing agent.; Aplicacion de tecnicas de fosfatacion sobre acero al carbon y aluminio, utilizando como agente oxidante la nitroguanidina.

    Energy Technology Data Exchange (ETDEWEB)

    Briseno M, S A

    1995-10-01

    Phosphate coatings are inorganic crystalline deposits laid down uniformly on properly prepared surfaces by a chemical reaction with the treated base metal. The reaction consists in dissolving some surface metal by acid attack and then causing surface neutralization of the phosphate solution with consequent precipitation of the phosphate coating. Phosphate coatings do not provide appreciable corrosion protection in themselves. They are useful mainly as a base for paints, ensuring good adherence of paint to steel and decreasing the tendency for corrosion to under cut the paint film at scratches or other defects. We deposited phosphate on standard carbon steel, employing techniques of cold phosphate (at 40 Centigrade degrees and with a treatment time of 30 minutes) and hot phosphate (at 88 Centigrade degrees and with a treatment time of 15 minutes), where the latter gave the best results. Both methods used phosphate solutions of Zn/Mn and the catalyst Nitro guanidine. Aluminium surfaces of phosphate were used solutions of Cr and as catalyst Sodium bi fluoride. The phosphating on this surface we deposited at temperature of 50 degrees C with a treatment time of 10 minutes. We obtained a new phosphate coating on steel surfaces, these coatings were realized with a phosphate solution manufactured with the precipitates gathered during the hot phosphating on carbon steel. These coatings show excellent physical characteristics of corrosion resistance. The physical testings of the coatings phosphate obtained on carbon steel and aluminium surfaces. These testing were: roughness, thickness, microhardness and adhesion. The best results were showed in carbon steel phosphate with precipitated solutions. Activation analysis with thermic neutrons was used to determine the phosphate coatings composition. Finally, corrosion testings were realized by means of two methods; electrochemical and by weight loss methods (gravimetric). (Abstract Truncated)

  13. Gas chromatographic determination of Di-n-butyl phosphate in radioactive lean organic solvent of FBTR carbide fuel reprocessing

    International Nuclear Information System (INIS)

    Velavendan, P.; Ganesh, S.; Pandey, N.K.; Kamachi Mudali, U.; Natarajan, R.

    2011-01-01

    In the present work Di-n- butyl phosphate (DBP) a degraded product of Tri-n-butyl phosphate (TBP) formed by acid hydrolysis and radiolysis in the PUREX process was analyzed. Lean organic streams of different fuel burn-up FBTR carbide fuel reprocessing solution was determined by standard Gas Chromatographic technique. The method involves the conversion of non-volatile Di-n-butyl phosphate into volatile and stable derivatives by the action of diazomethane and then determined by Gas Chromatograph (GC). A calibration graph was made for DBP concentration range of 200-2000 ppm with correlation coefficient of 0.99587 and RSD 1.2 %. (author)

  14. Urban tree effects on soil organic carbon.

    Directory of Open Access Journals (Sweden)

    Jill L Edmondson

    Full Text Available Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ∼75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C∶N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

  15. Initial pH of medium affects organic acids production but do not affect phosphate solubilization.

    Science.gov (United States)

    Marra, Leandro M; de Oliveira-Longatti, Silvia M; Soares, Cláudio R F S; de Lima, José M; Olivares, Fabio L; Moreira, Fatima M S

    2015-06-01

    The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.

  16. Stocks of organic carbon in Estonian soils

    Directory of Open Access Journals (Sweden)

    Kõlli, Raimo

    2009-06-01

    Full Text Available The soil organic carbon (SOC stocks (Mg ha–1 ofautomorphic mineral (9 soil groups, hydromorphic mineral (7, and lowland organic soils (4 are given for the soil cover or solum layer as a whole and also for its epipedon (topsoil layer. The SOC stocks for forest, arable lands, and grasslands and for the entire Estonian soil cover were calculated on the basis of the mean SOC stock and distribution area of the respective soil type. In the Estonian soil cover (42 400 km2, a total of 593.8 ± 36.9 Tg of SOC is retained, with 64.9% (385.3 ± 27.5 Tg in the epipedon layer (O, H, and A horizons and 35.1% in the subsoil (B and E horizons. The pedo-ecological regularities of SOC retention in soils are analysed against the background of the Estonian soil ordination net.

  17. myo-Inositol-1-phosphate synthase is required for polar auxin transport and organ development

    KAUST Repository

    Chen, Hao

    2010-06-01

    myo-Inositol-1-phosphate synthase is a conserved enzyme that catalyzes the first committed and rate-limiting step in inositol biosynthesis. Despite its wide occurrence in all eukaryotes, the role of myo-inositol-1-phosphate synthase and de novo inositol biosynthesis in cell signaling and organism development has been unclear. In this study, we isolated loss-of-function mutants in the Arabidopsis MIPS1 gene from different ecotypes. It was found that all mips1 mutants are defective in embryogenesis, cotyledon venation patterning, root growth, and root cap development. The mutant roots are also agravitropic and have reduced basipetal auxin transport. mips1 mutants have significantly reduced levels of major phosphatidylinositols and exhibit much slower rates of endocytosis. Treatment with brefeldin A induces slower PIN2 protein aggregation in mips1, indicating altered PIN2 trafficking. Our results demonstrate that MIPS1 is critical for maintaining phosphatidylinositol levels and affects pattern formation in plants likely through regulation of auxin distribution. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Surface Properties of PAN-based Carbon Fibers Modified by Electrochemical Oxidization in Organic Electrolyte Systems

    Directory of Open Access Journals (Sweden)

    WU Bo

    2016-09-01

    Full Text Available PAN-based carbon fibers were modified by electrochemical oxidization using fatty alcohol polyoxyethylene ether phosphate (O3P, triethanolamine (TEOA and fatty alcohol polyoxyethylene ether ammonium phosphate (O3PNH4 as organic electrolyte respectively. Titration analysis, single fiber fracture strength measurement and field emission scanning electron microscopy (FE-SEM were used to evaluate the content of acidic functional group on the surface, mechanical properties and surface morphology of carbon fiber. The optimum process of electrochemical treatment obtained is at 50℃ for 2min and O3PNH4 (5%, mass fraction as the electrolyte with current density of 2A/g. In addition, the surface properties of modified carbon fibers were characterized by X-ray photoelectron spectroscopy (XPS and single fiber contact angle test. The results show that the hydrophilic acidic functional groups on the surface of carbon fiber which can enhance the surface energy are increased by the electrochemical oxidation using O3PNH4 as electrolyte, almost without any weakening to the mechanical properties of carbon fiber.

  19. Phosphate adsorption and precipitation on calcite under calco-carbonic equilibrium condition.

    Science.gov (United States)

    Li, Zhenxuan; Sun, Xiaowen; Huang, Lidong; Liu, Dagang; Yu, Luji; Wu, Hongsheng; Wei, Dongyang

    2017-09-01

    Phosphate (PO 4 3- ) removal on calcite often entails two processes: adsorption and precipitation. Separating these two processes is of great importance for assessment of PO 4 3- stability after removal. Thus, this study was aimed at finding a critical range of conditions for separating these two processes in calco-carbonic equilibrium, by adjusting PO 4 3- concentration, reaction time and pH. PO 4 3- removal kinetic results showed that: (I) At pH7.7, PO 4 3- removal was mainly by adsorption at initial PO 4 3- concentration ≤2.2 mg L -1 and reaction time ≤24 h, with dominant precipitation occurring at initial PO 4 3- concentration ≥3 mg L -1 after 24 h reaction; (II) At pH8.3, adsorption was the key removal process at initial PO 4 3- concentration ≤7.5 mg L -1 and reaction time ≤24 h, whereas precipitation was observed at initial PO 4 3- concentration of 10 mg L -1 after 24 h reaction, (III) At pH 9.1 and 10.1, PO 4 3- removal mechanism was mainly by adsorption at initial PO 4 3- concentration ≤10 mg L -1 within 24 h reaction. Based on the kinetic results, it is suggested that PO 4 3- precipitation will occur after 24 h reaction when saturation index of amorphous calcium phosphate is between 1.97 and 2.19. Besides, increasing PO 4 3- concentration does not cause a continuous decline of PO 4 3- removal percentage. Moreover, experimental removal data deviated largely from the theoretical adsorption value by CD-MUSIC model. These indicate occurrence of precipitation which is in agreement with the kinetic result. Therefore our study will provide fundamental reference information for better understanding of phosphorous stabilization after removal by calcite. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The Porcupine Bank Canyon coral mounds: oceanographic and topographic steering of deep-water carbonate mound development and associated phosphatic deposition

    Science.gov (United States)

    Mazzini, A.; Akhmetzhanov, A.; Monteys, X.; Ivanov, M.

    2012-06-01

    The head of a canyon system extending along the western Porcupine Bank (west of Ireland) and which accommodates a large field of giant carbonate mounds was investigated during two cruises (INSS 2000 and TTR-13). Multibeam and sidescan sonar data (600-1,150 m water depth) suggest that the pre-existing seabed topography acts as a significant factor controlling mound distribution and shape. The mounds are concentrated along the edges of the canyon or are associated with a complex fault system traced around the canyon head, comprising escarpments up to 60 m high and several km long. The sampling for geochemical and petrographic analysis of numerous types of authigenic deposits was guided by sidescan sonar and video recordings. Calcite-cemented biogenic rubble was observed at the top and on the flanks of the carbonate mounds, being associated with both living and dead corals ( Lophelia pertusa, Madrepora oculata and occasional Desmophyllum cristagalli). This can plausibly be explained by dissolution of coral debris facilitated by strong currents along the mound tops and flanks. In turn, the dissolved carbon is recycled and precipitated as interstitial micrite. Calcite, dolomite and phosphatic hardgrounds were identified in samples from the escarpment framing the eastern part of the survey area. The laterally extensive phosphatic hardgrounds represent a novel discovery in the region, supplying hard substrata for the establishment of new coral colonies. Based on existing knowledge of regional oceanographic conditions, complemented with new CTD measurements, it is suggested that water column stratification, enhanced bottom currents, and upwelling facilitate the deposition of organic matter, followed by phosphatisation leading to the formation of phosphate-glauconite deposits. The occurrence of strong bottom currents was confirmed by means of video observations combined with acoustic and sampling data, providing circumstantial evidence of fine- to medium-grained sand

  1. Two-step carbon coating of lithium vanadium phosphate as high-rate cathode for lithium-ion batteries

    Science.gov (United States)

    Kuang, Quan; Zhao, Yanming

    2012-10-01

    Carbon-coated Li3V2(PO4)3 was firstly prepared at 850 °C via two-step reaction method combined sol-gel and conventional solid-state synthesis by using VPO4/carbon as an intermediate. Two different carbon sources, citric acid and glucose as carbon additives in sequence, ultimately deduced double carbon-coated Li3V2(PO4)3 as a high-rate cathode material. The Li3V2(PO4)3/carbon with 4.39% residual carbon has a splendid electronic conductivity of 4.76×10-2 S cm-1. Even in the voltage window of 2.5-4.8 V, the Li3V2(PO4)3/carbon cathode can retain outstanding rate ability (170.4 mAh g-1 at 1.2 C, 101.9 mAh g-1 at 17 C), and no degradation is found after 120 C current rate. These phenomena show that the two-step carbon-coated Li3V2(PO4)3 can act as a fast charge-discharge cathode material for high-power Li-ion batteries. Furthermore, it's believed that this synthesize method can be easily transplanted to prepare other lithiated vanadium-based phosphates.

  2. Effects of Sucroferric Oxyhydroxide Compared to Lanthanum Carbonate and Sevelamer Carbonate on Phosphate Homeostasis and Vascular Calcifications in a Rat Model of Chronic Kidney Failure

    Directory of Open Access Journals (Sweden)

    Olivier Phan

    2015-01-01

    Full Text Available Elevated serum phosphorus, calcium, and fibroblast growth factor 23 (FGF23 levels are associated with cardiovascular disease in chronic renal disease. This study evaluated the effects of sucroferric oxyhydroxide (PA21, a new iron-based phosphate binder, versus lanthanum carbonate (La and sevelamer carbonate (Se, on serum FGF23, phosphorus, calcium, and intact parathyroid hormone (iPTH concentrations, and the development of vascular calcification in adenine-induced chronic renal failure (CRF rats. After induction of CRF, renal function was significantly impaired in all groups: uremic rats developed severe hyperphosphatemia, and serum iPTH increased significantly. All uremic rats (except controls then received phosphate binders for 4 weeks. Hyperphosphatemia and increased serum iPTH were controlled to a similar extent in all phosphate binder-treatment groups. Only sucroferric oxyhydroxide was associated with significantly decreased FGF23. Vascular calcifications of the thoracic aorta were decreased by all three phosphate binders. Calcifications were better prevented at the superior part of the thoracic and abdominal aorta in the PA21 treated rats. In adenine-induced CRF rats, sucroferric oxyhydroxide was as effective as La and Se in controlling hyperphosphatemia, secondary hyperparathyroidism, and vascular calcifications. The role of FGF23 in calcification remains to be confirmed.

  3. Calcification mechanism and bony bonding studies of calcium carbonate and composite aluminosilicate/calcium phosphate applied as biomaterials by using radioactivation methods

    International Nuclear Information System (INIS)

    Oudadesse, H.; Derrien, A.C.; Lucas-Girot, A.; Martin, S.; Cathelieau, G.

    2007-01-01

    Bony grafts are used as a filling biomaterial for defective bone. The introduction of new range of synthetic materials offers to surgeons additional possibilities to avoid virus transmission risks by using natural grafts in bony surgery. In this work, two materials, synthetic calcium carbonate and composite aluminosilicate/calcium phosphate were synthesized by an original method and experimented 'in vivo' as biomaterials for bony filling. Extracted biopsies were studied by several physico chemical and biological methods. The aim was to evaluate the kinetic resorption and bioconsolidation of these materials. We focused on the bioconsolidation between implant and bone by realising cartographies from the implant to the bone and on the calcification mechanism by determination of the origin of Ca and Sr responsible of the neo-formed bone. Neutron activation analysis (NAA), radiotracers 45 Ca* and 85 Sr* and proton-induced X-ray emission (PIXE) were used. Concerning the synthetic calcium carbonate, results show that twelve months after implantation, the mineral composition of implant becomes similar to that of the mature bone. The neoformed bone is composed with Ca and Sr coming from the organism when the Ca and Sr of the implant were progressively eliminated. Concerning the composite geopolymer/calcium phosphate, PIXE and histological studies reveal the intimate links between the bone and the implant starting with the first month after implantation. (author)

  4. 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.

  5. "Fabrication of arbitrarily shaped carbonate apatite foam based on the interlocking process of dicalcium hydrogen phosphate dihydrate".

    Science.gov (United States)

    Sugiura, Yuki; Tsuru, Kanji; Ishikawa, Kunio

    2017-08-01

    Carbonate apatite (CO 3 Ap) foam with an interconnected porous structure is highly attractive as a scaffold for bone replacement. In this study, arbitrarily shaped CO 3 Ap foam was formed from α-tricalcium phosphate (α-TCP) foam granules via a two-step process involving treatment with acidic calcium phosphate solution followed by hydrothermal treatment with NaHCO 3 . The treatment with acidic calcium phosphate solution, which is key to fabricating arbitrarily shaped CO 3 Ap foam, enables dicalcium hydrogen phosphate dihydrate (DCPD) crystals to form on the α-TCP foam granules. The generated DCPD crystals cause the α-TCP granules to interlock with each other, inducing an α-TCP/DCPD foam. The interlocking structure containing DCPD crystals can survive hydrothermal treatment with NaHCO 3 . The arbitrarily shaped CO 3 Ap foam was fabricated from the α-TCP/DCPD foam via hydrothermal treatment at 200 °C for 24 h in the presence of a large amount of NaHCO 3 .

  6. Organic acids production by rhizosphere microorganisms isolated from a Typic Melanudands and its effects on the inorganic phosphates solubilization

    Directory of Open Access Journals (Sweden)

    Eduardo José Serna Posso

    2017-04-01

    Full Text Available It has been established that organic acid secretion by rhizosphere microorganisms is one of the mechanisms to solubilize the phosphorus (P attached to insoluble mineral compounds in soil. This action is an important biotechnological alternative, especially in those soils where high fixation of this nutrient occurs, a very common situation in the tropics. This research evaluated the ability performed by five bacterial and five fungal isolates from Typic Melanudands soil to produce organic acids and generate available phosphorus from insoluble P sources. Given these concerns, the selected microorganisms were replicated for 7 days in liquid medium Pikovskaya (PVK modified sources tricalcium phosphate (P-Ca, aluminum phosphate (P-Al and iron phosphate (P-Fe. The results indicated that phosphorus availability in the media, correlates positively with the organic acids production in each of the sources used (P-Ca (0.63, P-Al (0.67 and P-Fe (0.63. In turn, the chemical processes linked to the phosphates solubilization (e.g., Ca availability affected the development of the microorganisms tested. Both, fungi and bacteria varied in their ability production and type of metabolized organic acids, the most frequent were as follows: citric and gluconic acid.

  7. Long-term progress prediction for the carbon steel corrosion in diluted artificial seawater with and without zinc / sodium carbonate mixed phosphate

    International Nuclear Information System (INIS)

    Fujii, Kazumi; Ishioka, Shinichi; Iwanami, Masaru; Kaneko, Tetsuji; Tanaka, Norihiko; Kawaharada, Yoshiyuki; Yokoyama, Yutaka; Umehara, Ryuji; Kato, Chiaki; Ueno, Fumiyoshi; Fukaya, Yuichi; Kumaga, Katsuhiko

    2017-01-01

    The Fukushima Daiichi Nuclear Power Plants (1F) were damaged by an unprecedented severe accident in the great east Japan earthquake on 11th, March, 2011, and seawater and fresh water were injected as an emergency countermeasure for the core cooling. The primary containment vessels (PCVs), made of carbon steel, were exposed to seawater and fresh water, and have had the possibility of corrosion. The PCVs of 1F are the most important equipment for the core cooling and removal of the fuel debris, the structural integrity of the PCV must be maintained until decommissioning. Therefore, evaluation of PCV carbon steel corrosion behavior is important, as well as evaluation of corrosion inhibitors as one of the corrosion protection methods. In this study, long-term immersion corrosion tests for up to 10000 hours were performed in diluted artificial seawater simulating 1F with and without zinc / sodium carbonate mixed phosphate. Based on the long-term immersion corrosion test results, diagnosis method of the reduction in plate thickness of the nuclear vessel was examined. The validity of the existing corrosion progress models following parabolic rate law was confirmed. The corrosion progress models were also applicable to the corrosion inhibited condition adding zinc / sodium carbonate mixed phosphate. It was found that the corrosion rate of carbon steel drastically fell down by adding this corrosion inhibitor. (author)

  8. Erosion of soil organic carbon: implications for carbon sequestration

    Science.gov (United States)

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.; McPherson, B.J.; Sundquist, E.T.

    2009-01-01

    Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

  9. Isotopic fractionation between organic carbon and carbonate carbon in Precambrian banded ironstone series from Brazil

    International Nuclear Information System (INIS)

    Schidlowski, M.; Eichmann, R.; Fiebiger, W.

    1976-01-01

    37 delta 13 Csub(org) and 9 delta 13 Csub(carb) values furnished by argillaceous and carbonate sediments from the Rio das Velhas and Minas Series (Minas Gerais, Brazil) have yielded means of -24.3 +- 3.9 promille [PDB] and -0.9 +- 1.4 promille [PDB], respectively. These results, obtained from a major sedimentary banded ironstone province with an age between 2 and 3 x 10 9 yr, support previous assumptions that isotopic fractionation between inorganic and organic carbon in Precambrian sediments is about the same as in Phanerozoic rocks. This is consistent with a theoretically expected constancy of the kinetic fractionation factor governing biological carbon fixation and, likewise, with a photosynthetic pedigree of the reduced carbon fraction of Precambrian rocks. (orig.) [de

  10. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP Synthesized from Porous Foraminifera Carbonate Macrospheres

    Directory of Open Access Journals (Sweden)

    Joshua Chou

    2013-12-01

    Full Text Available Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.

  11. Could a secular increase in organic burial explain the rise of oxygen? Insights from a geological carbon cycle model constrained by the carbon isotope record

    Science.gov (United States)

    Krissansen-Totton, J.; Kipp, M.; Catling, D. C.

    2017-12-01

    The stable isotopes of carbon in marine sedimentary rock provide a window into the evolution of the Earth system. Conventionally, a relatively constant carbon isotope ratio in marine sedimentary rocks has been interpreted as implying constant organic carbon burial relative to total carbon burial. Because organic carbon burial corresponds to net oxygen production from photosynthesis, it follows that secular changes in the oxygen source flux cannot explain the dramatic rise of oxygen over Earth history. Instead, secular declines in oxygen sink fluxes are often invoked as causes for the rise of oxygen. However, constant fractional organic burial is difficult to reconcile with tentative evidence for low phosphate concentrations in the Archean ocean, which would imply lower marine productivity and—all else being equal—less organic carbon burial than today. The conventional interpretation of the carbon isotope record rests on the untested assumption that the isotopic ratio of carbon inputs into the ocean reflect mantle isotopic values throughout Earth history. In practice, differing rates of carbonate and organic weathering will allow for changes in isotopic inputs, as suggested by [1] and [2]. However, these inputs can not vary freely because large changes in isotopic inputs would induce secular trends in carbon reservoirs, which are not observed in the isotope record. We apply a geological carbon cycle model to all Earth history, tracking carbon isotopes in crustal, mantle, and ocean reservoirs. Our model is constrained by the carbon isotope record such that we can determine the extent to which large changes in organic burial are permitted. We find both constant organic burial and 3-5 fold increases in organic burial since 4.0 Ga can be reconciled with the carbon isotope record. Changes in the oxygen source flux thus need to be reconsidered as a possible contributor to Earth's oxygenation. [1] L. A. Derry, Organic carbon cycling and the lithosphere, in Treatise on

  12. Phosphate tuned copper electrodeposition and promoted formic acid selectivity for carbon dioxide reduction

    DEFF Research Database (Denmark)

    Zhao, Jian; Sun, Libo; Canepa, Silvia

    2017-01-01

    Fabrication of catalytically active electrodes by electrodeposition is attractive due to its in situ nature, easy controllability, and large-scale operation capability. Most recently, modifying the electrodes with phosphate ligands through electrodepositing electrode materials has shown promising...

  13. Volatile organic carbon/air separation test using gas membranes

    International Nuclear Information System (INIS)

    King, C.V.; Kaschemekat, J.

    1993-08-01

    An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed

  14. Accumulation of organic carbon in northwestern Arabian sea sediments

    International Nuclear Information System (INIS)

    Khan, A.A.

    1999-01-01

    In this study accumulation of organic carbon in marine sediments of northwestern Arabian sea has been discussed. This paper presents the geochemical analysis of Organic carbon content and accumulation, delta 13 stable carbon isotope and Ba/Al. The primary objective was to investigate the high resolution information about the variations in paleoproductivity and source of organic matter in sediments below an upwelling area. Undisturbed sediments (Piston core NIOP-486) of late Pleistocene time were collected during Netherlands Indian Ocean Program (NIOP-1992-93). The core NIOP-486 was raised from a depth of 2077 meters near the Owen Ridge. This core records deposition history of last 200,000 years and includes 4 warm and 3 cold periods. The distribution of organic carbon content in studied core shows a pronounced cyclicity during glacial and interglacial stages. Organic carbon accumulation trends show that high sedimentation rates in glacial stages results in rapid burial and hence increase organic carbon accumulation. Paleoproductivity indicator Ba/Al has been used to compare with the organic carbon content and is correlated with the warm and cold periods variations in monsoons upwelling intensity. Generally, low paleoproductivity is found in glacial stages. The organic carbon content and accumulation, in sediments however seems to differ from the paleoproductivity trends shown by Ba/Al in glacial sediments of stage 6. Delta 13 C.org isotope results of the core NIOP-486 confirm that organic matter in sediments is predominantly marine (-20 to -23% ). (author)

  15. Effect of Azolla Based - Organic Fertilizer, Rock Phosphate and Rice Hull Ash on Rice Yield and Chemical Properties of Alfisols

    Directory of Open Access Journals (Sweden)

    Sudadi

    2014-07-01

    Full Text Available The application of chemical fertilizer for long time may adverse soil environment. Organic agriculture, for example combination use of azolla based-organic fertilizer, phosphate rock and rice hull ash, was one of ways that able to recover it. Research was conducted in Sukosari, Jumantono, Karanganyar while soi chemical properties analysis was analysed in Soil Chemistry and Fertility Laboratory, Fac. of Agriculture, Sebelas Maret University April to November 2013. Research design used was RAKL with 5 treatments, each repeated 5 times. The treatments applied were P0 (control, P1 ( azola inoculum dosage 250 g/m2 + phosphate rock + rice hull ash equal to 150 kg/ha KCl, P2 (azola inoculum dosage 500 g/m2 + phosphate rock equal to 150kg/ha, SP-36 + rice hull ash equal to 100 kg/ha KCl, P3 (manure dosage of 5 ton/ha,P4 (Urea 250 kg/ha + SP-36 150 kg/ha + KCl 100 kg/ha. Data analysed statistically by F test (Fisher test with level of confident 95% followed by DMRT (Duncan Multiple Range Test if any significant differences. The result showed that the treatment combination of azolla, phosphate rock and rice hull ash increase soil organic matter content, cation exchange capacity, available-P and exchangeable-K as well as rice yield ( (at harvest-dry grain weight and milled-dry grain weight.

  16. Phosphorus sorption on marine carbonate sediment: phosphonate as model organic compounds.

    Science.gov (United States)

    Huang, Xiao-Lan; Zhang, Jia-Zhong

    2011-11-01

    Organophosphonate, characterized by the presence of a stable, covalent, carbon to phosphorus (C-P) bond, is a group of synthetic or biogenic organophosphorus compounds. The fate of these organic phosphorus compounds in the environment is not well studied. This study presents the first investigation on the sorption of phosphorus (P) in the presence of two model phosphonate compounds, 2-aminothylphosphonoic acid (2-AEP) and phosphonoformic acid (PFA), on marine carbonate sediments. In contrast to other organic P compounds, no significant inorganic phosphate exchange was observed in seawater. P was found to adsorb on the sediment only in the presence of PFA, not 2-AEP. This indicated that sorption of P from phosphonate on marine sediment was compound specific. Compared with inorganic phosphate sorption on the same sediments, P sorption from organic phosphorus is much less in the marine environment. Further study is needed to understand the potential role of the organophosphonate compounds in biogeochemical cycle of phosphorus in the environment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. The EIS investigation of powder polyester coatings on phosphated low carbon steel: The effect of NaNO2 in the phosphating bath

    International Nuclear Information System (INIS)

    Jegdic, B.V.; Bajat, J.B.; Popic, J.P.; Stevanovic, S.I.; Miskovic-Stankovic, V.B.

    2011-01-01

    Highlights: → The effect of NaNO 2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO 2 . → EIS results and microscopic examinations correlate well with adhesion measurements. - Abstract: The effect of different type of iron-phosphate coatings on corrosion stability and adhesion characteristic of top powder polyester coating on steel was investigated. Iron-phosphate coatings were deposited on steel in the novel phosphating bath with or without NaNO 2 as an accelerator. The corrosion stability of the powder polyester coating was evaluated by electrochemical impedance spectroscopy (EIS), adhesion by pull-off and NMP test, while surface morphology of phosphate coatings were investigated by atomic force microscopy (AFM). The adhesion and corrosion stability of powder polyester coatings were improved with pretreatment based on iron-phosphate coating deposited from NaNO 2 -free bath.

  18. Mangrove litter production and organic carbon pools in the ...

    African Journals Online (AJOL)

    Mngazana Estuary is an important source of mangrove litter and POC for the adjacent marine environment, possibly sustaining nearshore food webs. Keywords: Dissolved organic carbon, harvesting, litter production, mangroves, particulate organic carbon, Rhizophora mucronata, South Africa African Journal of Aquatic ...

  19. State-Space Estimation of Soil Organic Carbon Stock

    Science.gov (United States)

    Ogunwole, Joshua O.; Timm, Luis C.; Obidike-Ugwu, Evelyn O.; Gabriels, Donald M.

    2014-04-01

    Understanding soil spatial variability and identifying soil parameters most determinant to soil organic carbon stock is pivotal to precision in ecological modelling, prediction, estimation and management of soil within a landscape. This study investigates and describes field soil variability and its structural pattern for agricultural management decisions. The main aim was to relate variation in soil organic carbon stock to soil properties and to estimate soil organic carbon stock from the soil properties. A transect sampling of 100 points at 3 m intervals was carried out. Soils were sampled and analyzed for soil organic carbon and other selected soil properties along with determination of dry aggregate and water-stable aggregate fractions. Principal component analysis, geostatistics, and state-space analysis were conducted on the analyzed soil properties. The first three principal components explained 53.2% of the total variation; Principal Component 1 was dominated by soil exchange complex and dry sieved macroaggregates clusters. Exponential semivariogram model described the structure of soil organic carbon stock with a strong dependence indicating that soil organic carbon values were correlated up to 10.8m.Neighbouring values of soil organic carbon stock, all waterstable aggregate fractions, and dithionite and pyrophosphate iron gave reliable estimate of soil organic carbon stock by state-space.

  20. Dilution limits dissolved organic carbon utilization in the deep ocean

    NARCIS (Netherlands)

    Arrieta, J.M.; Mayol, E.; Hansman, R.L.; Herndl, G.J.; Dittmar, T.; Duarte, C.M.

    2015-01-01

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An

  1. Organic carbon accumulation in Brazilian mangal sediments

    Science.gov (United States)

    Sanders, Christian J.; Smoak, Joseph M.; Sanders, Luciana M.; Sathy Naidu, A.; Patchineelam, Sambasiva R.

    2010-12-01

    This study reviews the organic carbon (OC) accumulation rates in mangrove forests, margins and intertidal mudflats in geographically distinct areas along the Brazilian coastline (Northeastern to Southern). Our initial results indicate that the mangrove forests in the Northeastern region of Brazil are accumulating more OC (353 g/m 2/y) than in the Southeastern areas (192 g/m 2/y) being that the sediment accumulation rates, 2.8 and 2.5 mm/y, and OC content ˜7.1% and ˜5.8% (dry sediment weight) were contributing factors to the discrepancies between the forests. The intertidal mudflats on the other hand showed substantially greater OC accumulation rates, sedimentation rates and content 1129 g/m 2/y and 234 g/m 2/y; 7.3 and 3.4 mm/y; 10.3% and ˜2.7% (OC of dry sediment weight content), respectively, in the Northeastern compared to the Southeastern region. Mangrove forests in the South-Southeastern regions of Brazil may be more susceptible to the rising sea level, as they are geographically constricted by the vast mountain ranges along the coastline.

  2. Inferring absorbing organic carbon content from AERONET data

    Directory of Open Access Journals (Sweden)

    A. Arola

    2011-01-01

    Full Text Available Black carbon, light-absorbing organic carbon (often called "brown carbon" and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated the amount of light–absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon levels in biomass burning regions of South America and Africa are relatively high (about 15–20 mg m−2 during biomass burning season, while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30–35 mg m−2 during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by the global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while the opposite is true in urban areas in India and China.

  3. Inferring absorbing organic carbon content from AERONET data

    Science.gov (United States)

    Arola, A.; Schuster, G.; Myhre, G.; Kazadzis, S.; Dey, S.; Tripathi, S. N.

    2011-01-01

    Black carbon, light-absorbing organic carbon (often called "brown carbon") and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated the amount of light-absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon) levels in biomass burning regions of South America and Africa are relatively high (about 15-20 mg m-2 during biomass burning season), while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30-35 mg m-2 during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by the global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while the opposite is true in urban areas in India and China.

  4. Anthropogenic Forcing of Carbonate and Organic Carbon Preservation in Marine Sediments.

    Science.gov (United States)

    Keil, Richard

    2017-01-03

    Carbon preservation in marine sediments, supplemented by that in large lakes, is the primary mechanism that moves carbon from the active surficial carbon cycle to the slower geologic carbon cycle. Preservation rates are low relative to the rates at which carbon moves between surface pools, which has led to the preservation term largely being ignored when evaluating anthropogenic forcing of the global carbon cycle. However, a variety of anthropogenic drivers-including ocean warming, deoxygenation, and acidification, as well as human-induced changes in sediment delivery to the ocean and mixing and irrigation of continental margin sediments-all work to decrease the already small carbon preservation term. These drivers affect the cycling of both carbonate and organic carbon in the ocean. The overall effect of anthropogenic forcing in the modern ocean is to decrease delivery of carbon to sediments, increase sedimentary dissolution and remineralization, and subsequently decrease overall carbon preservation.

  5. Maize source leaf adaptation to nitrogen deficiency affects not only nitrogen and carbon metabolism but also control of phosphate homeostasis.

    Science.gov (United States)

    Schlüter, Urte; Mascher, Martin; Colmsee, Christian; Scholz, Uwe; Bräutigam, Andrea; Fahnenstich, Holger; Sonnewald, Uwe

    2012-11-01

    Crop plant development is strongly dependent on the availability of nitrogen (N) in the soil and the efficiency of N utilization for biomass production and yield. However, knowledge about molecular responses to N deprivation derives mainly from the study of model species. In this article, the metabolic adaptation of source leaves to low N was analyzed in maize (Zea mays) seedlings by parallel measurements of transcriptome and metabolome profiling. Inbred lines A188 and B73 were cultivated under sufficient (15 mM) or limiting (0.15 mM) nitrate supply for up to 30 d. Limited availability of N caused strong shifts in the metabolite profile of leaves. The transcriptome was less affected by the N stress but showed strong genotype- and age-dependent patterns. N starvation initiated the selective down-regulation of processes involved in nitrate reduction and amino acid assimilation; ammonium assimilation-related transcripts, on the other hand, were not influenced. Carbon assimilation-related transcripts were characterized by high transcriptional coordination and general down-regulation under low-N conditions. N deprivation caused a slight accumulation of starch but also directed increased amounts of carbohydrates into the cell wall and secondary metabolites. The decrease in N availability also resulted in accumulation of phosphate and strong down-regulation of genes usually involved in phosphate starvation response, underlining the great importance of phosphate homeostasis control under stress conditions.

  6. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

    International Nuclear Information System (INIS)

    He, Fupo; Ren, Weiwei; Tian, Xiumei; Liu, Wei; Wu, Shanghua; Chen, Xiaoming

    2016-01-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

  7. Comparative study on in vivo response of porous calcium carbonate composite ceramic and biphasic calcium phosphate ceramic

    Energy Technology Data Exchange (ETDEWEB)

    He, Fupo, E-mail: fphebm@126.com [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Ren, Weiwei [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Tian, Xiumei [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China); Liu, Wei; Wu, Shanghua [School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Chen, Xiaoming, E-mail: xmchenw@126.com [Department of Biomedical Engineering, School of Basic Sciences, Guangzhou Medical University, Guangzhou 510182 (China)

    2016-07-01

    In a previous study, robust calcium carbonate composite ceramics (CC/PG) were prepared by using phosphate-based glass (PG) as an additive, which showed good cell response. In the present study the in vivo response of porous CC/PG was compared to that of porous biphasic calcium phosphate ceramics (BCP), using a rabbit femoral critical-size grafting model. The materials degradation and bone formation processes were evaluated by general observation, X-ray radiography, micro-computed tomography, and histological examination. The results demonstrated excellent biocompatibility and osteoconductivity, and progressive degradation of CC/PG and BCP. Although the in vitro degradation rate of CC/PG was distinctly faster than that of BCP, at 4 week post-implantation, the bone generation and material degradation of CC/PG were less than those of BCP. Nevertheless, at postoperative week 8, the increment of bone formation and material degradation of CC/PG was pronouncedly larger than that of BCP. These results show that CC/PG is a potential resorbable bone graft aside from the traditional synthetic ones. - Highlights: • A calcium carbonate composite ceramic (CC/PG) was acquired. • The in vivo response of CC/PG and biphasic calcium phosphate (BCP) was compared. • CC/PG showed faster in vitro degradation rate compared to BCP. • CC/PG showed less in vivo degradation and bone formation than BCP at week 4. • CC/PG had larger increment of degradation and bone formation than BCP at week 8.

  8. Organic chemistry of Murchison meteorite: Carbon isotopic fractionation

    Science.gov (United States)

    Yuen, G. U.; Blair, N. E.; Desmarais, D. J.; Cronin, J. R.; Chang, S.

    1986-01-01

    The carbon isotopic composition of individual organic compounds of meteoritic origin remains unknown, as most reported carbon isotopic ratios are for bulk carbon or solvent extractable fractions. The researchers managed to determine the carbon isotopic ratios for individual hydrocarbons and monocarboxylic acids isolated from a Murchison sample by a freeze-thaw-ultrasonication technique. The abundances of monocarboxylic acids and saturated hydrocarbons decreased with increasing carbon number and the acids are more abundant than the hydrocarbon with the same carbon number. For both classes of compounds, the C-13 to C-12 ratios decreased with increasing carbon number in a roughly parallel manner, and each carboxylic acid exhibits a higher isotopic number than the hydrocarbon containing the same number of carbon atoms. These trends are consistent with a kinetically controlled synthesis of higher homologues for lower ones.

  9. Carbon isotope ratios of organic matter in Bering Sea settling particles. Extremely high remineralization of organic carbon derived from diatoms

    International Nuclear Information System (INIS)

    Yasuda, Saki; Akagi, Tasuku; Naraoka, Hiroshi; Kitajima, Fumio; Takahashi, Kozo

    2016-01-01

    The carbon isotope ratios of organic carbon in settling particles collected in the highly-diatom-productive Bering Sea were determined. Wet decomposition was employed to oxidize relatively fresh organic matter. The amount of unoxidised organic carbon in the residue following wet decomposition was negligible. The δ 13 C of organic carbon in the settling particles showed a clear relationship against SiO 2 /CaCO 3 ratio of settling particles: approximately -26‰ and -19‰ at lower and higher SiO 2 /CaCO 3 ratios, respectively. The δ 13 C values were largely interpreted in terms of mixing of two major plankton sources. Both δ 13 C and compositional data can be explained consistently only by assuming that more than 98% of diatomaceous organic matter decays and that organic matter derived from carbonate-shelled plankton may remain much less remineralized. A greater amount of diatom-derived organic matter is discovered to be trapped with the increase of SiO 2 /CaCO 3 ratio of the settling particles. The ratio of organic carbon to inorganic carbon, known as the rain ratio, therefore, tends to increase proportionally with the SiO 2 /CaCO 3 ratio under an extremely diatom-productive condition. (author)

  10. Organic carbon input in shallow groundwater at Aspo, southeastern Sweden

    International Nuclear Information System (INIS)

    Wallin, B.

    1993-01-01

    The variation in carbon and oxygen isotopes in calcite fissure fillings and dissolved carbonate from shallow groundwaters has been examined at Aspo, southeastern Sweden. The shallow water lens is refilled by meteoric water and is considered as an open system. The σ 13 C-signatures of the dissolved carbonate fall within a narrow range of -15.8 to -17.4 per-thousand, indicative of organic an organic carbon source. The low σ 13 C-values suggest that input of soil-CO 2 is the dominating carbon source for the system. σ 13 C and σ 18 O-values in the calcite fissure fillings show a wide range in values with a possible two end-member mixing of early post glacial atmospheric CO 2 dominated system to a present day soil-CO 2 dominating carbon source

  11. Selection criteria for oxidation method in total organic carbon measurement.

    Science.gov (United States)

    Yoon, GeunSeok; Park, Sang-Min; Yang, Heuiwon; Tsang, Daniel C W; Alessi, Daniel S; Baek, Kitae

    2018-05-01

    During the measurement of total organic carbon (TOC), dissolved organic carbon is converted into CO 2 by using high temperature combustion (HTC) or wet chemical oxidation (WCO). However, the criteria for selecting the oxidation methods are not clear. In this study, the chemical structures of organic material were considered as a key factor to select the oxidation method used. Most non-degradable organic compounds showed a similar oxidation efficiency in both methods, including natural organic compounds, dyes, and pharmaceuticals, and thus both methods are appropriate to measure TOC in waters containing these compounds. However, only a fraction of the carbon in the halogenated compounds (perfluorooctanoic acid and trifluoroacetic acid) were oxidized using WCO, resulting in measured TOC values that are considerably lower than those determined by HTC. This result is likely due to the electronegativity of halogen elements which inhibits the approach of electron-rich sulfate radicals in the WCO, and the higher bond strength of carbon-halogen pairs as compared to carbon-hydrogen bonds, which results in a lower degree of oxidation of the compounds. Our results indicate that WCO could be used to oxidize most organic compounds, but may not be appropriate to quantify TOC in organic carbon pools that contain certain halogenated compounds. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Chloride pyrometallurgy of uranium ore. 1. Chlorination of phosphate ore using solid or gas chlorinating agent and carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1995-01-01

    A thermodynamical and pyrometallurgical study to recover uranium from the phosphate ores was undertaken using the chloride volatilization method. Iron was chlorinated with solid chlorinating agents such as NaCl and CaCl 2 in combination with activated carbon, which will be used for removing this element from the ore, but uranium was not. On the other hand, the chlorination using Cl 2 gas and activated carbon gave a good result at 1,223 K. Not only uranium but also iron, phosphorus, aluminum and silicon were found to form volatile chlorides which vaporized out of the ore, while calcium remained in the ore as non-volatile CaCl 2 . The chlorination condition was studied as functions of temperature, reaction time and carbon content. The volatilization ratio of uranium around 95% was obtained by heating the mixture of the ore and activated carbon (35 wt%) in a mixed gas flow of Cl 2 (200 ml/min) and N 2 (200 ml/min) at 1,223 K for 120 min. (author)

  13. Supercritical Water Oxidation Total Organic Carbon (TOC) Analysis

    Science.gov (United States)

    The work presented here is the evaluation of the modified wet‐oxidation method described as Supercritical Water Oxidation (SCWO) for the analysis of total organic carbon (TOC) in very difficult oil/gas produced water sample matrices.

  14. Organic carbon in Hanford single-shell tank waste

    International Nuclear Information System (INIS)

    Toth, J.J.; Willingham, C.E.; Heasler, P.G.; Whitney, P.D.

    1994-04-01

    Safety of Hanford single-shell tanks (SSTs) containing organic carbon is a concern because the carbon in the presence of oxidizers (NO 3 or NO 2 ) is combustible when sufficiently concentrated and exposed to elevated temperatures. A propagating chemical reaction could potentially occur at high temperature (above 200 C). The rapid increase in temperature and pressure within a tank might result in the release of radioactive waste constituents to the environment. The purpose of this study is to gather available laboratory information about the organic carbon waste inventories stored in the Hanford SSTs. Specifically, the major objectives of this investigation are: Review laboratory analytical data and measurements for SST composite core and supernatant samples for available organic data; Assess the correlation of organic carbon estimated utilizing the TRAC computer code compared to laboratory measurements; and From the laboratory analytical data, estimate the TOC content with confidence levels for each of the 149 SSTs

  15. Mini Total Organic Carbon Analyzer (miniTOCA)

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this development is to create a prototype hand-held, 1 to 2 liter size battery-powered Total Organic Carbon Analyzer (TOCA). The majority of...

  16. Development of a Soil Organic Carbon Baseline for Otjozondjupa, Namibia

    OpenAIRE

    Nijbroek, R.; Kempen, B.; Mutua, J.; Soderstrom, M.; Piikki, K.; Hengari, S.; Andreas, A.

    2017-01-01

    Land Degradation Neutrality (LDN) has been piloted in 14 countries and will be scaled up to over 120 countries. As a LDN pilot country, Namibia developed sub-national LDN baselines in Otjozondjupa Region. In addition to the three LDN indicators (soil organic carbon, land productivity and land cover change), Namibia also regards bush encroachment as an important form of land degradation. We collected 219 soil profiles and used Random Forest modelling to develop the soil organic carbon stock ba...

  17. Soil Organic Carbon in the Soil Scapes of Southeastern Tanzania

    OpenAIRE

    Rossi, Joni

    2009-01-01

    Soil organic carbon (SOC) is well known to maintain several functions. On the one hand, being the major component of soil organic matter (SOM),it is a determinant of soil physical and chemical properties, an important proxy for soil biological activity and a measure of soil productivity. Land use management that will enhance soil carbon (C) levels is therefore important for farmers and land use planners, particularly in semiarid and sub-humid Africa where severe soil degradation and desertifi...

  18. Organic carbon, nitrogen and phosphorus contents of some tea soils

    International Nuclear Information System (INIS)

    Ahmed, M.S.; Zamir, M.R.; Sanauallah, A.F.M.

    2005-01-01

    Soil samples were collected from Rungicherra Tea-Estate of Moulvibazar district, Bangladesh. Organic carbon, organic matter, total nitrogen and available phosphorus content of the collected soil of different topographic positions have been determined. The experimental data have been analyzed statistically and plotted against topography and soil depth. Organic carbon and organic matter content varied from 0.79 to 1.24% and 1.37 to 2.14%. respectively. Total nitrogen and available phosphorus content of these soils varied respectively from 0.095 to 0.13% and 2.31 to 4.02 ppm. (author)

  19. Effects of some organic materials on bicarbonate extractable phosphate content of soils having different pH

    Directory of Open Access Journals (Sweden)

    Nutullah Özdemir

    2016-10-01

    Full Text Available This study was carried out to determine the effects of rice husk compost (RC, town waste compost (TW and tobacco waste (TB on bicarbonate extractable phosphate content (P in soils having different pH levels under greenhouse conditions. Soil samples used in this study were taken from surfaces (0-20 cm of agricultural fields around Samsun, Northern Anatolia. The experiment was conducted according to split plot design with four doses of organic matterials (0, 2.5, 5.0 and 7.5, %. After a month of mixing organic matterials into soils, lettuce were grown in the medias. According to the results, RC, TW and TB applications into acidic (Tepecik, neutral (Kampüs and alkaline (Çetinkaya soils increased extractable P content. It was observed that effectiveness of organic matterials changed depend on soil reaction, type and dose of organic matterials. All organic wastes were more effective on increment of bicarbonate extractable phosphate content in neutral soil pH when compared the other soil pH levels.

  20. Investigation of the benzotriazole as addictive for carbon steel phosphating; Estudo da utilizacao do benzotriazol como aditivo para a fosfatizacao de aco carbono

    Energy Technology Data Exchange (ETDEWEB)

    Annies, V.; Cunha, M.T.; Rodrigues, P.R.P.; Banczek, E.P. [Universidade Estadual do Centro-Oeste, Guarapuava, PR (Brazil). Dept. de Quimica; Costa, I. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Terada, M. [Universidade de Sao Paulo (POLI/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    This work studied the viability of substitution of sodium nitrite (NaNO{sub 2}) for benzotriazole (BTAH) in the zinc phosphate bath (PZn+NaNO{sub 2}) for phosphating of carbon steel (SAE 1010). The characterization of the samples was carried out by Scanning Electron Microscopy, Optical Microscopy and X-ray diffraction. The chemical composition was evaluated by Energy Dispersive Spectroscopy. The corrosion behavior of the samples was investigated by Open Circuit Potential, Electrochemical Impedance Spectroscopy and Anodic Potentiodynamic Polarization Curves in a 0.5 mol L{sup -1} NaCl electrolyte. The experimental results showed that the phosphate layer obtained in the solution with benzotriazole (PZn+BTAH) presented better corrosion resistance properties than that obtained in sodium nitrite. The results demonstrated that the sodium nitrite NaNO{sub 2} can be replaced by benzotriazole (BTAH) in zinc phosphate baths. (author)

  1. Soil Organic Carbon assessment on two different forest management

    Science.gov (United States)

    Fernández Minguillón, Alex; Sauras Yera, Teresa; Vallejo Calzada, Ramón

    2017-04-01

    Soil Organic Carbon assessment on two different forest management. A.F. Minguillón1, T. Sauras1, V.R: Vallejo1. 1 Departamento de Biología Evolutiva, Ecología y Ciencias Ambientales, Universidad de Barcelona, Avenida Diagonal 643, 03080 Barcelona, Spain. Soils from arid and semiarid zones are characterized by a low organic matter content from scarce plant biomass and it has been proposed that these soils have a big capacity to carbon sequestration. According to IPCC ARS WG2 (2014) report and WG3 draft, increase carbon storage in terrestrial ecosystems has been identified such a potential tool for mitigation and adaptation to climate change. In ecological restoration context improve carbon sequestration is considered a management option with multiple benefits (win-win-win). Our work aims to analyze how the recently developed restoration techniques contributed to increases in terrestial ecosystem carbon storage. Two restoration techniques carried out in the last years have been evaluated. The study was carried out in 6 localities in Valencian Community (E Spain) and organic horizons of two different restoration techniques were evaluated; slash brush and thinning Aleppo pine stands. For each technique, carbon stock and its physical and chemical stability has been analysed. Preliminary results point out restoration zones acts as carbon sink due to (1) the relevant necromass input produced by slash brush increases C stock on the topsoil ;(2) Thinning increase carbon accumulation in vegetation.

  2. Methods of soil organic carbon determination in Brazilian savannah soils

    Directory of Open Access Journals (Sweden)

    Juliana Hiromi Sato

    2014-08-01

    Full Text Available Several methods exist for determining soil organic carbon, and each one has its own advantages and limitations. Consequently, a comparison of the experimental results obtained when these methods are employed is hampered, causing problems in the comparison of carbon stocks in soils. This study aimed at evaluating the analytical procedures used in the determination of carbon and their relationships with soil mineralogy and texture. Wet combustion methods, including Walkley-Black, Mebius and Colorimetric determination as well as dry combustion methods, such as Elemental and Gravimetric Analysis were used. Quantitative textural and mineralogical (kaolinite, goethite and gibbsite analyses were also carried out. The wet digestion methods underestimated the concentration of organic carbon, while the gravimetric method overestimated. Soil mineralogy interfered with the determination of carbon, with emphasis on the gravimetric method that was greatly influenced by gibbsite.

  3. Pathways of organic carbon oxidation in three continental margin sediments

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Jørgensen, Bo Barker; Fossing, Henrik

    1993-01-01

    We have combined several different methodologies to quantify rates of organic carbon mineralization by the various electron acceptors in sediments from the coast of Denmark and Norway. Rates of NH4+ and Sigma CO2 liberation sediment incubations were used with O2 penetration depths to conclude...... that O2 respiration accounted for only between 3.6-17.4% of the total organic carbon oxidation. Dentrification was limited to a narrow zone just below the depth of O2 penetration, and was not a major carbon oxidation pathway. The processes of Fe reduction, Mn reduction and sulfate reduction dominated...... organic carbon mineralization, but their relative significance varied depending on the sediment. Where high concentrations of Mn-oxide were found (3-4 wt% Mn), only Mn reduction occurred. With lower Mn oxide concentrations more typical of coastal sediments, Fe reduction and sulfate reduction were most...

  4. Incorporation of 14C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication

    International Nuclear Information System (INIS)

    Sikorska, M.; Gorzkowski, B.; Szumanska, G.; Smialek, M.

    1975-01-01

    Incorporation of 14 C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication was studied. In brains of rats tested on the 20, 30 and 60th minute of exposure to CO and immediately after removal from the chamber the enzyme activity showed no essential deviation from the control level. In the group of rats tested 1 hour after taking them out from the chamber increase of the enzyme activity was noticed, amounting to about 33% of the control value. The brains tested 24 hours after exposure showed the largest increase of the enzyme activity by about 94%. In the next time periods, 48 and 72 hours after intoxication, the enzyme activity was decreasing. The glycogen content in brains of control animals increased 3 hours after CO intoxication by about 69%. The increase of glycogen synthesis was expressed by increase of the total radioactivity, which amounted to 160% of the control value. (Z.M.)

  5. Stable isotope compositions of organic carbon and contents of ...

    African Journals Online (AJOL)

    The stable isotope compositions of organic carbon (OC), and contents of OC and nitrogen for four sediment cores recovered from lakes Makat (located in the Ngorongoro Crater), Ndutu and Masek (located in the Serengeti Plains) are used to document sources of organic matter (OM) and climatic changes in sub-arid ...

  6. Organic loss in drained wetland: managing the carbon footprint

    NARCIS (Netherlands)

    Durham, B.; van de Noort, R.; Martens, V.V.; Vorenhout, M.

    2012-01-01

    The recent installation of land drains at Star Carr, Yorkshire, UK, has been linked with loss of preservation quality in this important Mesolithic buried landscape, challenging the PARIS principle. Historically captured organic carbon, including organic artefacts, is being converted to soluble

  7. Microbial Contribution to Organic Carbon Sequestration in Mineral Soil

    Science.gov (United States)

    Soil productivity and sustainability are dependent on soil organic matter (SOM). Our understanding on how organic inputs to soil from microbial processes become converted to SOM is still limited. This study aims to understand how microbes affect carbon (C) sequestration and the formation of recalcit...

  8. Production of dissolved organic carbon in aquatic sediment suspensions

    NARCIS (Netherlands)

    Koelmans, A.A.; Prevo, L.

    2003-01-01

    In many water quality models production of dissolved organic carbon (DOC) is modelled as mineralisation from particulate organic matter (POM). In this paper it is argued that the DOC production from dessicated sediments by water turbulence may be of similar importance
    In many water quality

  9. Competition of a parathion-hydrolyzing Flavobacterium with bacteria from ditch water in carbon-, nitrate- and phosphate-limited continuous cultures

    NARCIS (Netherlands)

    Sprenger, W.; Dijkstra, A.; Zwart, G.; Van Agterveld, M.P.; Van Noort, P.C.M.; Parsons, J.R.

    2003-01-01

    The effect of competition for macroelements with bacteria from ditch water on the parathion-hydrolyzing Flavobacterium sp. ATCC 27551 (FB) was investigated within mixed continuous cultures under carbon-, nitrate- or phosphate-limited conditions. The high initial rate of parathion hydrolysis

  10. [Roles of soil dissolved organic carbon in carbon cycling of terrestrial ecosystems: a review].

    Science.gov (United States)

    Li, Ling; Qiu, Shao-Jun; Liu, Jing-Tao; Liu, Qing; Lu, Zhao-Hua

    2012-05-01

    Soil dissolved organic carbon (DOC) is an active fraction of soil organic carbon pool, playing an important role in the carbon cycling of terrestrial ecosystems. In view of the importance of the carbon cycling, this paper summarized the roles of soil DOC in the soil carbon sequestration and greenhouse gases emission, and in considering of our present ecological and environmental problems such as soil acidification and climate warming, discussed the effects of soil properties, environmental factors, and human activities on the soil DOC as well as the response mechanisms of the DOC. This review could be helpful to the further understanding of the importance of soil DOC in the carbon cycling of terrestrial ecosystems and the reduction of greenhouse gases emission.

  11. Organic carbon efflux from a deciduous forest catchment in Korea

    Directory of Open Access Journals (Sweden)

    S. J. Kim

    2010-04-01

    Full Text Available Soil infiltration and surface discharge of precipitation are critical processes that affect the efflux of Dissolved Organic Carbon (DOC and Particulate Organic Carbon (POC in forested catchments. Concentrations of DOC and POC can be very high in the soil surface in most forest ecosystems and their efflux may not be negligible particularly under the monsoon climate. In East Asia, however, there are little data available to evaluate the role of such processes in forest carbon budget. In this paper, we address two basic questions: (1 how does stream discharge respond to storm events in a forest catchment? and (2 how much DOC and POC are exported from the catchment particularly during the summer monsoon period? To answer these questions, we collected hydrological data (e.g., precipitation, soil moisture, runoff discharge, groundwater level and conducted hydrochemical analyses (including DOC, POC, and six tracers in a deciduous forest catchment in Gwangneung National Arboretum in west-central Korea. Based on the end-member mixing analysis of the six storm events during the summer monsoon in 2005, the surface discharge was estimated as 30 to 80% of the total runoff discharge. The stream discharge responded to precipitation within 12 h during these storm events. The annual efflux of DOC and POC from the catchment was estimated as 0.04 and 0.05 t C ha−1 yr−1, respectively. Approximately 70% of the annual organic carbon efflux occurred during the summer monsoon period. Overall, the annual efflux of organic carbon was estimated to be about 10% of the Net Ecosystem carbon Exchange (NEE obtained by eddy covariance measurement at the same site. Considering the current trends of increasing intensity and amount of summer rainfall and the large interannual variability in NEE, ignoring the organic carbon efflux from forest catchments would result in an inaccurate estimation of the carbon sink strength of forest ecosystems in the monsoon

  12. Modeling soil organic carbon with Quantile Regression: Dissecting predictors' effects on carbon stocks

    KAUST Repository

    Lombardo, Luigi; Saia, Sergio; Schillaci, Calogero; Mai, Paul Martin; Huser, Raphaë l

    2017-01-01

    Soil Organic Carbon (SOC) estimation is crucial to manage both natural and anthropic ecosystems and has recently been put under the magnifying glass after the Paris agreement 2016 due to its relationship with greenhouse gas. Statistical applications

  13. Stable carbon isotope composition of organic material and carbonate in sediment of a swamp and lakes in Honshu island, Japan

    International Nuclear Information System (INIS)

    Ishizuka, Toshio

    1978-01-01

    Recent sediments from a swamp and lakes in Honshu were analyzed for organic carbon and carbonate contents, and stable isotope ratios of carbon in the organic materials and carbonate. delta C 13 values of the carbonate tend to be distinctly larger than those of organic carbon in reducing condition as natural gas field, whereas in oxidizing SO 4 -reducing conditions, they are slightly larger than those of organic carbon within the limited range of a few per mil. Carbon isotopic compositions of organic carbon in sediment of the swamp, Obuchi-numa, were analyzed and compared with habitat analysis of associated fossil diatoms. deltaC 13 values of organic carbon in the sediment vary in correlation with the species abundance in habitat of the associated fossil diatoms, ranging from fresh-water (-0.0282) to coastal marine (-0.0236) via brackish. (auth.)

  14. Chemistry of organic carbon in soil with relationship to the global carbon cycle

    International Nuclear Information System (INIS)

    Post, W.M. III.

    1988-01-01

    Various ecosystem disturbances alter the balances between production of organic matter and its decomposition and therefore change the amount of carbon in soil. The most severe perturbation is conversion of natural vegetation to cultivated crops. Conversion of natural vegetation to cultivated crops results in a lowered input of slowly decomposing material which causes a reduction in overall carbon levels. Disruption of soil matrix structure by cultivation leads to lowered physical protection of organic matter resulting in an increased net mineralization rate of soil carbon. Climate change is another perturbation that affects the amount and composition of plant production, litter inputs, and decomposition regimes but does not affect soil structure directly. Nevertheless, large changes in soil carbon storage are probable with anticipated CO 2 induced climate change, particularly in northern latitudes where anticipated climate change will be greatest (MacCracken and Luther 1985) and large amounts of soil organic matter are found. It is impossible, given the current state of knowledge of soil organic matter processes and transformations to develop detailed process models of soil carbon dynamics. Largely phenomenological models appear to be developing into predictive tools for understanding the role of soil organic matter in the global carbon cycle. In particular, these models will be useful in quantifying soil carbon changes due to human land-use and to anticipated global climate and vegetation changes. 47 refs., 7 figs., 2 tabs

  15. Are Polyphosphates or Phosphate Esters Prebiotic Reagents?

    Science.gov (United States)

    Keefe, Anthony D.; Miller, Stanley L.

    1995-01-01

    It is widely held that there was a phosphate compound in prebiotic chemistry that played the role of adenosine triphosphate and that the first living organisms had ribose-phosphate in the backbone of their genetic material. However, there are no known efficient prebiotic synthesis of high-energy phosphates or phosphate esters. We review the occurrence of phosphates in nature, the efficiency of the volcanic synthesis of P4O10, the efficiency of polyphosphate synthesis by heating phosphate minerals under geological conditions, and the use of high-energy organic compounds such as cyanamide or hydrogen cyanide. These are shown to be inefficient processes especially when the hydrolysis of the polyphosphates is taken into account. For example, if a whole atmosphere of methane or carbon monoxide were converted to cyanide which somehow synthesized polyphosphates quantitatively, the polyphosphate concentration in the ocean would still have been insignificant. We also attempted to find more efficient high-energy polymerizing agents by spark discharge syntheses, but without success. There may still be undiscovered robust prebiotic syntheses of polyphosphates, or mechanisms for concentrating them, but we conclude that phosphate esters may not have been constituents of the first genetic material. Phosphoanhydrides are also unlikely as prebiotic energy sources.

  16. Managing oral phosphate binder medication expenditures within the Medicare bundled end-stage renal disease prospective payment system: economic implications for large U.S. dialysis organizations.

    Science.gov (United States)

    Park, Haesuk; Rascati, Karen L; Keith, Michael S

    2015-06-01

    From January 2016, payment for oral-only renal medications (including phosphate binders and cinacalcet) was expected to be included in the new Medicare bundled end-stage renal disease (ESRD) prospective payment system (PPS). The implementation of the ESRD PPS has generated concern within the nephrology community because of the potential for inadequate funding and the impact on patient quality of care. To estimate the potential economic impact of the new Medicare bundled ESRD PPS reimbursement from the perspective of a large dialysis organization in the United States. We developed an interactive budget impact model to evaluate the potential economic implications of Medicare payment changes to large dialysis organizations treating patients with ESRD who are receiving phosphate binders. In this analysis, we focused on the budget impact of the intended 2016 integration of oral renal drugs, specifically oral phosphate binders, into the PPS. We also utilized the model to explore the budgetary impact of a variety of potential shifts in phosphate binder market shares under the bundled PPS from 2013 to 2016. The base model predicts that phosphate binder costs will increase to $34.48 per dialysis session in 2016, with estimated U.S. total costs for phosphate binders of over $682 million. Based on these estimates, a projected Medicare PPS $33.44 reimbursement rate for coverage of all oral-only renal medications (i.e., phosphate binders and cinacalcet) would be insufficient to cover these costs. A potential renal drugs and services budget shortfall for large dialysis organizations of almost $346 million was projected. Our findings suggest that large dialysis organizations will be challenged to manage phosphate binder expenditures within the planned Medicare bundled rate structure. As a result, large dialysis organizations may have to make treatment choices in light of potential inadequate funding, which could have important implications for the quality of care for patients

  17. Erosion of organic carbon in the Arctic as a geological carbon dioxide sink.

    Science.gov (United States)

    Hilton, Robert G; Galy, Valier; Gaillardet, Jérôme; Dellinger, Mathieu; Bryant, Charlotte; O'Regan, Matt; Gröcke, Darren R; Coxall, Helen; Bouchez, Julien; Calmels, Damien

    2015-08-06

    Soils of the northern high latitudes store carbon over millennial timescales (thousands of years) and contain approximately double the carbon stock of the atmosphere. Warming and associated permafrost thaw can expose soil organic carbon and result in mineralization and carbon dioxide (CO2) release. However, some of this soil organic carbon may be eroded and transferred to rivers. If it escapes degradation during river transport and is buried in marine sediments, then it can contribute to a longer-term (more than ten thousand years), geological CO2 sink. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers at high latitudes remains poorly constrained. Here, we quantify the source of POC in the Mackenzie River, the main sediment supplier to the Arctic Ocean, and assess its flux and fate. We combine measurements of radiocarbon, stable carbon isotopes and element ratios to correct for rock-derived POC. Our samples reveal that the eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5,800 ± 800 years, much older than the POC in large tropical rivers. From the measured biospheric POC content and variability in annual sediment yield, we calculate a biospheric POC flux of 2.2(+1.3)(-0.9) teragrams of carbon per year from the Mackenzie River, which is three times the CO2 drawdown by silicate weathering in this basin. Offshore, we find evidence for efficient terrestrial organic carbon burial over the Holocene period, suggesting that erosion of organic carbon-rich, high-latitude soils may result in an important geological CO2 sink.

  18. Maximum organic carbon limits at different melter feed rates (U)

    International Nuclear Information System (INIS)

    Choi, A.S.

    1995-01-01

    This report documents the results of a study to assess the impact of varying melter feed rates on the maximum total organic carbon (TOC) limits allowable in the DWPF melter feed. Topics discussed include: carbon content; feed rate; feed composition; melter vapor space temperature; combustion and dilution air; off-gas surges; earlier work on maximum TOC; overview of models; and the results of the work completed

  19. Methodology guideline. Organization of conference neutral in carbon

    International Nuclear Information System (INIS)

    2007-01-01

    In the framework of the Climate Plan elaborated by the french government, the neutral carbon principle must be applied to conference organization and the international travels. This guide has two main functions: heighten to allow everybody to understand the climate change impacts and problems, and bring some recommendations and tools to implement a neutral carbon conference (transport, welcome, accommodation and meal). (A.L.B.)

  20. Characterization of activated carbon produced from urban organic waste

    Directory of Open Access Journals (Sweden)

    Abdul Gani Haji

    2013-10-01

    Full Text Available The difficulties to decompose organic waste can be handled naturally by pyrolisis so it can  decomposes quickly that produces charcoal as the product. This study aims to investigate the characteristics of activated carbon from urban organic waste. Charcoal results of pyrolysis of organic waste activated with KOH 1.0 M at a temperature of 700 and 800oC for 60 to 120 minutes. Characteristics of activated carbon were identified by Furrier Transform Infra Red (FTIR, Scanning Electron Microscopy (SEM, and X-Ray Diffraction (XRD. However, their quality is determined yield, moisture content, ash, fly substances, fixed carbon, and the power of adsorption of iodine and benzene. The identified functional groups on activated carbon, such as OH (3448,5-3436,9 cm-1, and C=O (1639,4 cm-1. In general, the degree and distance between the layers of active carbon crystallites produced activation in all treatments showed no significant difference. The pattern of activated carbon surface topography structure shows that the greater the pore formation in accordance with the temperature increase the more activation time needed. The yield of activated carbon obtained ranged from 72.04 to 82.75%. The results of characterization properties of activated carbon was obtained from 1.11 to 5.41% water, 13.68 to 17.27% substance fly, 20.36 to 26.59% ash, and 56.14 to 62.31% of fixed carbon . Absorption of activated carbon was good enough at 800oC and 120 minutes of activation time, that was equal to 409.52 mg/g of iodine and 14.03% of benzene. Activated carbon produced has less good quality, because only the water content and flying substances that meet the standards.Doi: 10.12777/ijse.5.2.89-94 [How to cite this article: Haji, A.G., Pari, G., Nazar, M., and Habibati.  (2013. Characterization of activated carbon produced from urban organic waste . International Journal of Science and Engineering, 5(2,89-94. Doi: 10.12777/ijse.5.2.89-94

  1. Cost effective tools for soil organic carbon monitoring

    Science.gov (United States)

    Shepherd, Keith; Aynekulu, Ermias

    2013-04-01

    There is increasing demand for data on soil properties at fine spatial resolution to support management and planning decisions. Measurement of soil organic carbon has attracted much interest because (i) soil organic carbon is widely cited as a useful indicator of soil condition and (ii) of the importance of soil carbon in the global carbon cycle and climate mitigation strategies. However in considering soil measurement designs there has been insufficient attention given to careful analysis of the specific decisions that the measurements are meant to support and on what measurements have high information value for decision-making. As a result, much measurement effort may be wasted or focused on the wrong variables. A cost-effective measurement is one that reduces risk in decisions and does not cost more than the societal returns to additional evidence. A key uncertainty in measuring soil carbon as a soil condition indicator is what constitutes a good or bad level of carbon on a given soil. A measure of soil organic carbon concentration may have limited value for informing management decisions without the additional information required to interpret it, and so expending further efforts on improving measurements to increase precision may then have no value to improving the decision. Measuring soil carbon stock changes for carbon trading purposes requires high levels of measurement precision but there is still large uncertainty on whether the costs of measurement exceed the benefits. Since the largest cost component in soil monitoring is often travel to the field and physically sampling soils, it is generally cost-effective to meet multiple objectives by analysing a number of properties on a soil sample. Diffuse reflectance infrared spectroscopy is playing a key role in allowing multiple soil properties to be determined rapidly and at low cost. The method provides estimation of multiple soil properties (e.g. soil carbon, texture and mineralogy) in one measurement

  2. Amorphous Ca-phosphate precursors for Ca-carbonate biominerals mediated by Chromohalobacter marismortui

    NARCIS (Netherlands)

    Rivadeneyra, María Angustias; Martín-Algarra, Agustín; Sánchez-Román, Mónica; Sánchez-Navas, Antonio; Martín-Ramos, José Daniel

    Although diverse microbial metabolisms are known to induce the precipitation of carbonate minerals, the mechanisms involved in the bacterial mediation, in particular nucleation, are still debated. The study of aragonite precipitation by Chromohalobacter marismortui during the early stages (3-7 days)

  3. Bone tissue engineering on amorphous carbonated apatite and crystalline octacalcium phosphate-coated titanium discs

    NARCIS (Netherlands)

    Dekker, Robert J.; de Bruijn, Joost Dick; Stigter, Martin; Barrère, F.; Layrolle, Pierre; van Blitterswijk, Clemens

    2005-01-01

    Poor fixation of bone replacement implants, e.g. the artificial hip, in implantation sites with inferior bone quality and quantity may be overcome by the use of implants coated with a cultured living bone equivalent. In this study, we tested, respectively, amorphous carbonated apatite (CA)- and

  4. Lithium iron phosphate/carbon nanocomposite film cathodes for high energy lithium ion batteries

    International Nuclear Information System (INIS)

    Liu, Yanyi; Liu, Dawei; Zhang, Qifeng; Yu, Danmei; Liu, Jun; Cao, Guozhong

    2011-01-01

    This paper reports sol-gel derived nanostructured LiFePO4/carbon nanocomposite film cathodes exhibiting enhanced electrochemical properties and cyclic stabilities. LiFePO4/carbon films were obtained by spreading sol on Pt coated Si wafer followed by ambient drying overnight and annealing/pyrolysis at elevated temperature in nitrogen. Uniform and crack-free LiFePO4/carbon nanocomposite films were readily obtained and showed olivine phase as determined by means of X-Ray Diffractometry. The electrochemical characterization revealed that, at a current density of 200 mA/g (1.2 C), the nanocomposite film cathodes demonstrated an initial lithium-ion intercalation capacity of 312 mAh/g, and 218 mAh/g after 20 cycles, exceeding the theoretical storage capacity of conventional LiFePO4 electrode. Such enhanced Li-ion intercalation performance could be attributed to the nanocomposite structure with fine crystallite size below 20 nm as well as the poor crystallinity which provides a partially open structure allowing easy mass transport and volume change associated with Li-ion intercalation. Moreover the surface defect introduced by carbon nanocoating could also effectively facilitate the charge transfer and phase transitions.

  5. Comparing carbon to carbon: Organic and inorganic carbon balances across nitrogen fertilization gradients in rainfed vs. irrigated Midwest US cropland

    Science.gov (United States)

    Hamilton, S. K.; McGill, B.

    2017-12-01

    The top meter of the earth's soil contains about twice the amount of carbon than the atmosphere. Agricultural management practices influence whether a cropland soil is a net carbon source or sink. These practices affect both organic and inorganic carbon cycling although the vast majority of studies examine the former. We will present results from several rarely-compared carbon fluxes: carbon dioxide emissions and sequestration from lime (calcium carbonate) weathering, dissolved gases emitted from groundwater-fed irrigation, dissolved organic carbon (DOC) leaching to groundwater, and soil organic matter storage. These were compared in a corn-soybean-wheat rotation under no-till management across a nitrogen fertilizer gradient where half of the replicated blocks are irrigated with groundwater. DOC and liming fluxes are also estimated from a complementary study in neighboring plots comparing a gradient of management practices from conventional to biologically-based annuals and perennials. These studies were conducted at the Kellogg Biological Station Long Term Ecological Research site in Michigan where previous work estimated that carbon dioxide emissions from liming accounted for about one quarter of the total global warming impact (GWI) from no-till systems—our work refines that figure. We will present a first time look at the GWI of gases dissolved in groundwater that are emitted when the water equilibrates with the atmosphere. We will explore whether nitrogen fertilizer and irrigation increase soil organic carbon sequestration by producing greater crop biomass and residues or if they enhance microbial activity, increasing decomposition of organic matter. These results are critical for more accurately estimating how intensive agricultural practices affect the carbon balance of cropping systems.

  6. Reinforcement of calcium phosphate cement with multi-walled carbon nanotubes and bovine serum albumin for injectable bone substitute applications

    NARCIS (Netherlands)

    Chew, K.K.; Low, K.L.; Zein, S.H.S.; McPhail, D.; Gerhardt, L.C.; Roether, J.A.; Boccaccini, A.R.

    2011-01-01

    This paper presents the development of novel alternative injectable calcium phosphate cement (CPC) composites for orthopaedic applications. The new CPC composites comprise ß-tri-calcium phosphate (ß-TCP) and di-calcium phosphate anhydrous (DCPA) mixed with bovine serum albumin (BSA) and incorporated

  7. Experimental and in silico investigations of organic phosphates and phosphonates sorption on polymer-ceramic monolithic materials and hydroxyapatite.

    Science.gov (United States)

    Pietrzyńska, Monika; Zembrzuska, Joanna; Tomczak, Rafał; Mikołajczyk, Jakub; Rusińska-Roszak, Danuta; Voelkel, Adam; Buchwald, Tomasz; Jampílek, Josef; Lukáč, Miloš; Devínsky, Ferdinand

    2016-10-10

    A method based on experimental and in silico evaluations for investigating interactions of organic phosphates and phosphonates with hydroxyapatite was developed. This quick and easy method is used for determination of differences among organophosphorus compounds of various structures in their mineral binding affinities. Empirical sorption evaluation was carried out using liquid chromatography with tandem mass spectrometry or UV-VIS spectroscopy. Raman spectroscopy was used to confirm sorption of organic phosphates and phosphonates on hydroxyapatite. Polymer-ceramic monolithic material and bulk hydroxyapatite were applied as sorbent materials. Furthermore, a Polymer-ceramic Monolithic In-Needle Extraction device was used to investigate both sorption and desorption steps. Binding energies were computed from the fully optimised structures utilising Density Functional Theory (DFT) at B3LYP/6-31+G(d,p) level. Potential pharmacologic and toxic effects of the tested compounds were estimated by the Prediction of the Activity Spectra of Substances using GeneXplain software. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Carbon-14 measurements and characterization of dissolved organic carbon in ground water

    International Nuclear Information System (INIS)

    Murphy, E.M.

    1987-01-01

    Carbon-14 was measured in the dissolved organic carbon (DOC) in ground water and compared with 14 C analyses of dissolved inorganic carbon (DIC). Two field sites were used for this study; the Stripa mine in central Sweden, and the Milk River Aquifer in southern Alberta, Canada. The Stripa mine consists of a Precambrian granite dominated by fracture flow, while the Milk River Aquifer is a Cretaceous sandstone aquifer characterized by porous flow. At both field sites, 14 C analyses of the DOC provide additional information on the ground-water age. Carbon-14 was measured on both the hydrophobic and hydrophilic organic fractions of the DOC. The organic compounds in the hydrophobic and hydrophilic fractions were also characterized. The DOC may originate from kerogen in the aquifer matrix, from soil organic matter in the recharge zone, of from a combination of these two sources. Carbon-14 analyses, along with characterization of the organics, were used to determine this origin. Carbon-14 analyses of the hydrophobic fraction in the Milk River Aquifer suggest a soil origin, while 14 C analyses of the hydrophilic fraction suggest an origin within the Cretaceous sediments (kerogen) or from the shale in contact with the aquifer

  9. [Soil organic carbon fractionation methods and their applications in farmland ecosystem research: a review].

    Science.gov (United States)

    Zhang, Guo; Cao, Zhi-ping; Hu, Chan-juan

    2011-07-01

    Soil organic carbon is of heterogeneity in components. The active components are sensitive to agricultural management, while the inert components play an important role in carbon fixation. Soil organic carbon fractionation mainly includes physical, chemical, and biological fractionations. Physical fractionation is to separate the organic carbon into active and inert components based on the density, particle size, and its spatial distribution; chemical fractionation is to separate the organic carbon into various components based on the solubility, hydrolizability, and chemical reactivity of organic carbon in a variety of extracting agents. In chemical fractionation, the dissolved organic carbon is bio-available, including organic acids, phenols, and carbohydrates, and the acid-hydrolyzed organic carbon can be divided into active and inert organic carbons. Simulated enzymatic oxidation by using KMnO4 can separate organic carbon into active and non-active carbon. Biological fractionation can differentiate microbial biomass carbon and potential mineralizable carbon. Under different farmland management practices, the chemical composition and pool capacity of soil organic carbon fractions will have different variations, giving different effects on soil quality. To identify the qualitative or quantitative relationships between soil organic carbon components and carbon deposition, we should strengthen the standardization study of various fractionation methods, explore the integrated application of different fractionation methods, and sum up the most appropriate organic carbon fractionation method or the appropriate combined fractionation methods for different farmland management practices.

  10. Speleothem records of acid sulphate deposition and organic carbon mobilisation

    Science.gov (United States)

    Wynn, Peter; Fairchild, Ian; Bourdin, Clement; Baldini, James; Muller, Wolfgang; Hartland, Adam; Bartlett, Rebecca

    2017-04-01

    Dramatic increases in measured surface water DOC in recent decades have been variously attributed to either temperature rise, or destabilisation of long-term soil carbon pools following sulphur peak emissions status. However, whilst both drivers of DOC dynamics are plausible, they remain difficult to test due to the restricted nature of the available records of riverine DOC flux (1978 to present), and the limited availability of SO2 emissions inventory data at the regional scale. Speleothems offer long term records of both sulphur and carbon. New techniques to extract sulphur concentrations and isotopes from speleothem calcite have enabled archives of pollution history and environmental acidification to be reconstructed. Due to the large dynamic range in sulphur isotopic values from end member sources (marine aerosol +21 ‰ to continental biogenic emissions -30 ‰) and limited environmental fractionation under oxidising conditions, sulphur isotopes form an ideal tracer of industrial pollution and environmental acidification in the palaeo-record. We couple this acidification history to the carbon record, using organic matter fluorescence and trace metals. Trace metal ratios and abundance can be used to infer the type and size of organic ligand and are therefore sensitive to changes in temperature as a driver of organic carbon processing and biodegradation. This allows fluorescent properties and ratios of trace metals in speleothem carbonate to be used to represent both the flux of organic carbon into the cave as well as the degradation pathway. Here we present some of the first results of this work, exploring sulphur acidification as a mechanistic control on carbon solubility and export throughout the twentieth century.

  11. Linking aboveground net primary productivity to soil carbon and dissolved organic carbon in complex terrain

    Science.gov (United States)

    F.S. Peterson; K. Lajtha

    2013-01-01

    Factors influencing soil organic matter (SOM) stabilization and dissolved organic carbon (DOC) content in complex terrain, where vegetation, climate, and topography vary over the scale of a few meters, are not well understood. We examined the spatial correlations of lidar and geographic information system-derived landscape topography, empirically measured soil...

  12. 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

  13. Yucca Mountain Area Saturated Zone Dissolved Organic Carbon Isotopic Data

    International Nuclear Information System (INIS)

    Thomas, James; Decker, David; Patterson, Gary; Peterman, Zell; Mihevc, Todd; Larsen, Jessica; Hershey, Ronald

    2007-01-01

    Groundwater samples in the Yucca Mountain area were collected for chemical and isotopic analyses and measurements of water temperature, pH, specific conductivity, and alkalinity were obtained at the well or spring at the time of sampling. For this project, groundwater samples were analyzed for major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC). The U.S. Geological Survey (USGS) performed all the fieldwork on this project including measurement of water chemistry field parameters and sample collection. The major ions dissolved in the groundwater, deuterium, oxygen-18, and carbon isotopes of dissolved inorganic carbon (DIC) were analyzed by the USGS. All preparation and processing of samples for DOC carbon isotopic analyses and geochemical modeling were performed by the Desert Research Institute (DRI). Analysis of the DOC carbon dioxide gas produced at DRI to obtain carbon-13 and carbon-14 values was conducted at the University of Arizona Accelerator Facility (a NSHE Yucca Mountain project QA qualified contract facility). The major-ion chemistry, deuterium, oxygen-18, and carbon isotopes of DIC were used in geochemical modeling (NETPATH) to determine groundwater sources, f ow paths, mixing, and ages. The carbon isotopes of DOC were used to calculate groundwater ages that are independent of DIC model corrected carbon-14 ages. The DIC model corrected carbon-14 calculated ages were used to evaluate groundwater travel times for mixtures of water including water beneath Yucca Mountain. When possible, groundwater travel times were calculated for groundwater flow from beneath Yucca Mountain to down gradient sample sites. DOC carbon-14 groundwater ages were also calculated for groundwaters in the Yucca Mountain area. When possible, groundwater travel times were estimated for groundwater flow from beneath Yucca Mountain to down gradient groundwater sample sites using the DOC calculated

  14. Mineralogy and geochemistry of phosphate minerals and brannerite from the Proterozoic Carbon Leader Reef gold and uranium placer deposit, Witwatersrand, South Africa

    International Nuclear Information System (INIS)

    Oberthuer, T.

    1987-01-01

    Yttrium-phosphate, the most common phosphate phase, is closely associated with detrital uraninite. It is assumed having formed by the reaction of mobile phosphate with Y and HREE liberated from the lattice of detrital uraninite, during diagenesis and/or metamorphism of the sediments. Authigenic brannerite (UTi 2-3 O 6-8 ) is well-defined microscopically and geochemically. Textural relationships indicate that both titanium migrated to uraninite, forming brannerite, and mobile uranium caused the 'branneritization' of rutile/leucoxene. Microprobe analyses demonstrate that brannerite from the Carbon Leader Reef displays a distinct and small variation of UO 2 /TiO 2 ratios, which lie close to the theoretical value of 1.117 for UTi 3 O 8 , in contrast to uraniferous leucoxene/brannerite from other Witwatersrand-type deposits, the latter showing a wide scatter of UO 2 /TiO 2 ratios. (orig./HP)

  15. Organic carbon production, mineralization and preservation on the Peruvian margin

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Lomnitz, U.; Montes, I.; Treude, T.; Gier, J.; Hensen, C.; Dengler, M.; Stolpovsky, K.; Bryant, L. D.; Wallmann, K.

    2014-09-01

    Carbon cycling in Peruvian margin sediments (11° S and 12° S) was examined at 16 stations from 74 m on the inner shelf down to 1024 m water depth by means of in situ flux measurements, sedimentary geochemistry and modeling. Bottom water oxygen was below detection limit down to ca. 400 m and increased to 53 μM at the deepest station. Sediment accumulation rates and benthic dissolved inorganic carbon fluxes decreased rapidly with water depth. Particulate organic carbon (POC) content was lowest on the inner shelf and at the deep oxygenated stations (< 5%) and highest between 200 and 400 m in the oxygen minimum zone (OMZ, 15-20%). The organic carbon burial efficiency (CBE) was unexpectedly low on the inner shelf (< 20%) when compared to a global database, for reasons which may be linked to the frequent ventilation of the shelf by oceanographic anomalies. CBE at the deeper oxygenated sites was much higher than expected (max. 81%). Elsewhere, CBEs were mostly above the range expected for sediments underlying normal oxic bottom waters, with an average of 51 and 58% for the 11° S and 12° S transects, respectively. Organic carbon rain rates calculated from the benthic fluxes alluded to a very efficient mineralization of organic matter in the water column, with a Martin curve exponent typical of normal oxic waters (0.88 ± 0.09). Yet, mean POC burial rates were 2-5 times higher than the global average for continental margins. The observations at the Peruvian margin suggest that a lack of oxygen does not affect the degradation of organic matter in the water column but promotes the preservation of organic matter in marine sediments.

  16. Soil organic carbon dynamics jointly controlled by climate, carbon inputs, soil properties and soil carbon fractions.

    Science.gov (United States)

    Luo, Zhongkui; Feng, Wenting; Luo, Yiqi; Baldock, Jeff; Wang, Enli

    2017-10-01

    Soil organic carbon (SOC) dynamics are regulated by the complex interplay of climatic, edaphic and biotic conditions. However, the interrelation of SOC and these drivers and their potential connection networks are rarely assessed quantitatively. Using observations of SOC dynamics with detailed soil properties from 90 field trials at 28 sites under different agroecosystems across the Australian cropping regions, we investigated the direct and indirect effects of climate, soil properties, carbon (C) inputs and soil C pools (a total of 17 variables) on SOC change rate (r C , Mg C ha -1  yr -1 ). Among these variables, we found that the most influential variables on r C were the average C input amount and annual precipitation, and the total SOC stock at the beginning of the trials. Overall, C inputs (including C input amount and pasture frequency in the crop rotation system) accounted for 27% of the relative influence on r C , followed by climate 25% (including precipitation and temperature), soil C pools 24% (including pool size and composition) and soil properties (such as cation exchange capacity, clay content, bulk density) 24%. Path analysis identified a network of intercorrelations of climate, soil properties, C inputs and soil C pools in determining r C . The direct correlation of r C with climate was significantly weakened if removing the effects of soil properties and C pools, and vice versa. These results reveal the relative importance of climate, soil properties, C inputs and C pools and their complex interconnections in regulating SOC dynamics. Ignorance of the impact of changes in soil properties, C pool composition and C input (quantity and quality) on SOC dynamics is likely one of the main sources of uncertainty in SOC predictions from the process-based SOC models. © 2017 John Wiley & Sons Ltd.

  17. Mapping residual organics and carbonate at grain boundaries and in the amorphous interphase in mouse incisor enamel

    Directory of Open Access Journals (Sweden)

    Lyle M Gordon

    2015-03-01

    Full Text Available Dental enamel has evolved to resist the most grueling conditions of mechanical stress, fatigue, and wear. Adding insult to injury, it is exposed to the frequently corrosive environment of the oral cavity. While its hierarchical structure is unrivaled in its mechanical resilience, heterogeneity in the distribution of magnesium ions and the presence of Mg-substituted amorphous calcium phosphate (Mg-ACP as an intergranular phase have recently been shown to increase the susceptibility of mouse enamel to acid attack. Herein we investigate the distribution of two important constituents of enamel, residual organic matter and inorganic carbonate. We find that organics, carbonate, and possibly water show distinct distribution patterns in the mouse enamel crystallites, at simple grain boundaries, and in the amorphous interphase at multiple grain boundaries. This has implications for the resistance to acid corrosion, mechanical properties, and the mechanism by which enamel crystals grow during amelogenesis.

  18. Minerilization of carbon and nitrogen of organic residues from ...

    African Journals Online (AJOL)

    Minerilization of carbon and nitrogen of organic residues from selected plants in a tropical cropping system. O M Onuh, HA Okorie. Abstract. No Abstract. Journal of Agriculture and Food Sciences Vol. 3 (1) 2005 pp. 11-24. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  19. Estimation of organic carbon loss potential in north of Iran

    Science.gov (United States)

    Shahriari, A.; Khormali, F.; Kehl, M.; Welp, G.; Scholz, Ch.

    2009-04-01

    The development of sustainable agricultural systems requires techniques that accurately monitor changes in the amount, nature and breakdown rate of soil organic matter and can compare the rate of breakdown of different plant or animal residues under different management systems. In this research, the study area includes the southern alluvial and piedmont plains of Gorgan River extended from east to west direction in Golestan province, Iran. Samples from 10 soil series and were collected from cultivation depth (0-30 cm). Permanganate-oxidizable carbon (POC) an index of soil labile carbon, was used to show soil potential loss of organic carbon. In this index shows the maximum loss of OC in a given soil. Maximum loss of OC for each soil series was estimated through POC and bulk density (BD). The potential loss of OC were estimated between 1253263 and 2410813 g/ha Carbon. Stable organic constituents in the soil include humic substances and other organic macromolecules that are intrinsically resistant against microbial attack, or that are physically protected by adsorption on mineral surfaces or entrapment within clay and mineral aggregates. However, the (Clay + Silt)/OC ratio had a negative significant (p < 0.001) correlation with POC content, confirming the preserving effect of fine particle.

  20. Development of a Soil Organic Carbon Baseline for Otjozondjupa, Namibia

    NARCIS (Netherlands)

    Nijbroek, R.; Kempen, B.; Mutua, J.; Soderstrom, M.; Piikki, K.; Hengari, S.; Andreas, A.

    2017-01-01

    Land Degradation Neutrality (LDN) has been piloted in 14 countries and will be scaled up to over 120 countries. As a LDN pilot country, Namibia developed sub-national LDN baselines in Otjozondjupa Region. In addition to the three LDN indicators (soil organic carbon, land productivity and land cover

  1. Organic carbon in the sediments of Mandovi estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Alagarsamy, R.

    Total organic carbon (TOC) in surficial sediments in Mandovi Estuary, Goa, India varies widely from 0.1 to 3% (av. 1.05%). Highest values of TOC (2.4-3%) lie close to the mouth region and indicate no definite trend in its variation in the estuarine...

  2. Organic carbon stocks in the soils of Brazil

    NARCIS (Netherlands)

    Batjes, N.H.

    2005-01-01

    Soil organic carbon stocks to 1 m for Brazil, calculated using an updated Soil and Terrain (SOTER) database and simulation of phenoforms, are 65.9-67.5 Pg C, of which 65% is in the Amazonian region of Brazil. Other researchers have obtained similar gross results, despite very different spatial

  3. Evaluation of the soil organic carbon, nitrogen and available ...

    African Journals Online (AJOL)

    The result obtained indicates that the level of these chemical properties were generally low as compared to standard measures and parameter for ratings soil fertility in the Nigerian Savanna. Keywords: Status of organic carbon, total nitrogen, available phosphorus, top horizons, research farm. Bowen Journal of Agriculture ...

  4. Effects of organic nitrogen and carbon sources on mycelial growth ...

    African Journals Online (AJOL)

    Grifola umbellate is a famous and expensive Chinese herb medicine and the main medicinal component is polysaccharide mainly produced by its mycelia. Effects of organic nitrogen and carbon resources on mycelial growth and polysaccharides production of a medicinal mushroom, G. umbellate were studied in the ...

  5. Spatial distribution of soil organic carbon stocks in France

    Directory of Open Access Journals (Sweden)

    M. P. Martin

    2011-05-01

    Full Text Available Soil organic carbon plays a major role in the global carbon budget, and can act as a source or a sink of atmospheric carbon, thereby possibly influencing the course of climate change. Changes in soil organic carbon (SOC stocks are now taken into account in international negotiations regarding climate change. Consequently, developing sampling schemes and models for estimating the spatial distribution of SOC stocks is a priority. The French soil monitoring network has been established on a 16 km × 16 km grid and the first sampling campaign has recently been completed, providing around 2200 measurements of stocks of soil organic carbon, obtained through an in situ composite sampling, uniformly distributed over the French territory.

    We calibrated a boosted regression tree model on the observed stocks, modelling SOC stocks as a function of other variables such as climatic parameters, vegetation net primary productivity, soil properties and land use. The calibrated model was evaluated through cross-validation and eventually used for estimating SOC stocks for mainland France. Two other models were calibrated on forest and agricultural soils separately, in order to assess more precisely the influence of pedo-climatic variables on SOC for such soils.

    The boosted regression tree model showed good predictive ability, and enabled quantification of relationships between SOC stocks and pedo-climatic variables (plus their interactions over the French territory. These relationships strongly depended on the land use, and more specifically, differed between forest soils and cultivated soil. The total estimate of SOC stocks in France was 3.260 ± 0.872 PgC for the first 30 cm. It was compared to another estimate, based on the previously published European soil organic carbon and bulk density maps, of 5.303 PgC. We demonstrate that the present estimate might better represent the actual SOC stock distributions of France, and consequently that the

  6. Research and engineering assessment of biological solubilization of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, R.D.; McIlwain, M.E.; Losinski, S.J.; Taylor, D.D.

    1993-03-01

    This research and engineering assessment examined a microbial phosphate solubilization process as a method of recovering phosphate from phosphorus containing ore compared to the existing wet acid and electric arc methods. A total of 860 microbial isolates, collected from a range of natural environments were tested for their ability to solubilize phosphate from rock phosphate. A bacterium (Pseudomonas cepacia) was selected for extensive characterization and evaluation of the mechanism of phosphate solubilization and of process engineering parameters necessary to recover phosphate from rock phosphate. These studies found that concentration of hydrogen ion and production of organic acids arising from oxidation of the carbon source facilitated microbial solubilization of both pure chemical insoluble phosphate compounds and phosphate rock. Genetic studies found that phosphate solubilization was linked to an enzyme system (glucose dehydrogenase). Process-related studies found that a critical solids density of 1% by weight (ore to liquid) was necessary for optimal solubilization. An engineering analysis evaluated the cost and energy requirements for a 2 million ton per year sized plant, whose size was selected to be comparable to existing wet acid plants.

  7. A facile method to synthesize polypyrrole nanoparticles in the presence of natural organic phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Chao; Mo, Haodao [State Key Laboratory Breeding Base of Nonferrous Metals and Specific Materials Processing, College of Material Science and Engineering, Guilin University of Technology, Guilin 541004 (China); Zang, Limin, E-mail: D14S004@akita-pu.ac.jp [Department of Machine Intelligence and Systems Engineering, Faculty of Systems Engineering, Akita Prefectural University, Yurihonjo City, Akita 015-0055 (Japan); Qiu, Jianhui; Sakai, Eiichi; Wu, Xueli [Department of Machine Intelligence and Systems Engineering, Faculty of Systems Engineering, Akita Prefectural University, Yurihonjo City, Akita 015-0055 (Japan)

    2014-09-15

    The conductive polymers with unique nanostructures have attracted intense interest due to their potential application. Here the well-defined polypyrrole nanoparticles were facile fabricated via the facile chemical oxidative polymerization of pyrrole with high feeding ratio of phytic acid. Phytic acid is a renewable resource and a natural carbohydrate compound with a vast number of phosphate groups from plant which was used as the template and dopant for the nanostructured conductive polymer for the first time. The samples exhibit the well-defined nanoparticles observed by scanning electron microscope (SEM) and atomic force microscope (AFM). The PPy nanoparticles were achieved and outstanding electrical conductivity as high as 5263 S m{sup −1} was obtained with the feeding mass ratio of phytic acid: pyrrole=3:7. Furthermore, the polypyrrole nanoparticles were characterized with Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and electrical conductivity techniques.

  8. Latitudinal gradients in degradation of marine dissolved organic carbon.

    Directory of Open Access Journals (Sweden)

    Carol Arnosti

    Full Text Available Heterotrophic microbial communities cycle nearly half of net primary productivity in the ocean, and play a particularly important role in transformations of dissolved organic carbon (DOC. The specific means by which these communities mediate the transformations of organic carbon are largely unknown, since the vast majority of marine bacteria have not been isolated in culture, and most measurements of DOC degradation rates have focused on uptake and metabolism of either bulk DOC or of simple model compounds (e.g. specific amino acids or sugars. Genomic investigations provide information about the potential capabilities of organisms and communities but not the extent to which such potential is expressed. We tested directly the capabilities of heterotrophic microbial communities in surface ocean waters at 32 stations spanning latitudes from 76°S to 79°N to hydrolyze a range of high molecular weight organic substrates and thereby initiate organic matter degradation. These data demonstrate the existence of a latitudinal gradient in the range of complex substrates available to heterotrophic microbial communities, paralleling the global gradient in bacterial species richness. As changing climate increasingly affects the marine environment, changes in the spectrum of substrates accessible by microbial communities may lead to shifts in the location and rate at which marine DOC is respired. Since the inventory of DOC in the ocean is comparable in magnitude to the atmospheric CO(2 reservoir, such a change could profoundly affect the global carbon cycle.

  9. Organic carbon production, mineralisation and preservation on the Peruvian margin

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Lomnitz, U.; Montes, I.; Treude, T.; Liebetrau, V.; Gier, J.; Hensen, C.; Dengler, M.; Stolpovsky, K.; Bryant, L. D.; Wallmann, K.

    2015-03-01

    Carbon cycling in Peruvian margin sediments (11 and 12° S) was examined at 16 stations, from 74 m water depth on the middle shelf down to 1024 m, using a combination of in situ flux measurements, sedimentary geochemistry and modelling. Bottom water oxygen was below detection limit down to ca. 400 m and increased to 53 μM at the deepest station. Sediment accumulation rates decreased sharply seaward of the middle shelf and subsequently increased at the deep stations. The organic carbon burial efficiency (CBE) was unusually low on the middle shelf (60%) at the deep oxygenated sites. In line with other studies, CBE was elevated under oxygen-deficient waters in the mid-water oxygen minimum zone. Organic carbon rain rates calculated from the benthic fluxes alluded to efficient mineralisation of organic matter in the water column compared to other oxygen-deficient environments. The observations at the Peruvian margin suggest that a lack of oxygen does not greatly affect the degradation of organic matter in the water column but promotes the preservation of organic matter in sediments.

  10. Methodology guideline. Organization of conference neutral in carbon; Guide methodologique. Organisation de conference neutre en carbone

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    In the framework of the Climate Plan elaborated by the french government, the neutral carbon principle must be applied to conference organization and the international travels. This guide has two main functions: heighten to allow everybody to understand the climate change impacts and problems, and bring some recommendations and tools to implement a neutral carbon conference (transport, welcome, accommodation and meal). (A.L.B.)

  11. Latitudinal gradients in degradation of marine dissolved organic carbon

    DEFF Research Database (Denmark)

    Arnosti, Carol; Steen, Andrew; Ziervogel, Kai

    2011-01-01

    unknown, since the vast majority of marine bacteria have not been isolated in culture, and most measurements of DOC degradation rates have focused on uptake and metabolism of either bulk DOC or of simple model compounds (e.g. specific amino acids or sugars). Genomic investigations provide information......Heterotrophic microbial communities cycle nearly half of net primary productivity in the ocean, and play a particularly important role in transformations of dissolved organic carbon (DOC). The specific means by which these communities mediate the transformations of organic carbon are largely...... about the potential capabilities of organisms and communities but not the extent to which such potential is expressed. We tested directly the capabilities of heterotrophic microbial communities in surface ocean waters at 32 stations spanning latitudes from 76 ºS to 79 ºN to hydrolyze a range of high...

  12. A glassy carbon electrode modified with cerium phosphate nanotubes for the simultaneous determination of hydroquinone, catechol and resorcinol.

    Science.gov (United States)

    Li, Zhen; Yue, Yuhua; Hao, Yanjun; Feng, Shun; Zhou, Xianli

    2018-03-12

    A nafion film containing cerium phosphate nanotubes was pasted onto a glassy carbon electrode (GCE) to obtain a sensor for hydroquinone (HQ). The morphologies and components of the coating were characterized by transmission electron microscopy, scanning electron microscopy and energy-dispersive spectroscopy. Cyclic voltammetry and differential pulse voltammetry (DPV) showed the specific surface of the electrode to be significantly increased and the electron transfer rate to be accelerated. The modified GCE was applied to the determination of hydroquinone (HQ) via DPV. The oxidation current increases linearly in the 0.23 μM to 16 mM HQ concentration range which is as wide as five orders of magnitude. The limit of detection is 0.12 μM (based on a signal-to-noise ratio of 3), and the sensitivity is 1.41 μA·μM -1  cm -2 . The method was further applied to the simultaneous determination of HQ, catechol and resorcinol. The potentials for the three species are well separated (20, 134, and 572 mV vs SCE). Average recoveries from (spiked) real water samples are between 95.2 and 107.0%, with relative standard deviations of 0.9~2.7% (for n = 3) at three spiking levels. The method was validated by independent assays using HPLC. Graphical abstract ᅟ.

  13. Adsorption of phosphate from aqueous solution using iron-zirconium modified activated carbon nanofiber: Performance and mechanism.

    Science.gov (United States)

    Xiong, Weiping; Tong, Jing; Yang, Zhaohui; Zeng, Guangming; Zhou, Yaoyu; Wang, Dongbo; Song, Peipei; Xu, Rui; Zhang, Chen; Cheng, Min

    2017-05-01

    Phosphate (P) removal is significant for the prevention of eutrophication in natural waters. In this paper, a novel adsorbent for the removal of P from aqueous solution was synthesized by loading zirconium oxide and iron oxide onto activated carbon nanofiber (ACF-ZrFe) simultaneously. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that P adsorption was highly pH dependent and the optimum pH was found to be 4.0. The isotherm of adsorption could be well described by the Langmuir model and the maximum P adsorption capacity was estimated to be 26.3mgP/g at 25°C. The kinetic data were well fitted to the pseudo-second-order equation, indicating that chemical sorption was the rate-limiting step. Moreover, co-existing ions including sulfate (SO 4 2- ), chloride (Cl - ), nitrate (NO 3 - ) and fluoride (F - ) exhibited a distinct effect on P adsorption with the order of F - >NO 3 - >Cl - >SO 4 2- . Further investigations by FT-IR spectroscopy and pH variations associated with the adsorption process revealed that ligands exchange and electrostatic interactions were the dominant mechanisms for P adsorption. The findings reported in this work highlight the potential of using ACF-ZrFe as an effective adsorbent for the removal of P in natural waters. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Perfluorooctane sulfonate adsorption on powder activated carbon: Effect of phosphate (P) competition, pH, and temperature.

    Science.gov (United States)

    Qian, Jin; Shen, Mengmeng; Wang, Peifang; Wang, Chao; Li, Kun; Liu, Jingjing; Lu, Bianhe; Tian, Xin

    2017-09-01

    Powdered activated carbon (PAC), as an adsorbent, was applied to remove perfluorooctane sulfonate (PFOS) from aqueous solution. Laboratory batch experiments were performed to investigate the influences of phosphate (P) competition, temperature, and pH for PFOS adsorption onto PAC. The results showed that higher temperature favored PFOS adsorption in single and binary systems. The kinetic data fitted very well to the pseudo second-order kinetic model. Thermodynamically, the endothermic enthalpy of the PFOS adsorption in single and binary systems were 125.07 and 21.25 kJ mol -1 , respectively. The entropy of the PFOS adsorption in single and binary systems were 0.479 and 0.092 kJ mol -1  K -1 , respectively. And the Gibbs constants were negative. These results indicated that the adsorption processes were spontaneous. The adsorption isotherms of PFOS agreed well with the Langmuir model. In the single system, PFOS adsorption decreased with increased pH value. The difference in the amount of PFOS adsorption between the single and binary systems increased at higher pH. Frustrated total internal reflection (FTIR) demonstrated that P competition increased the hydrophilicity of the PAC and the electrostatic repulsion between PFOS and PAC, then the PFOS adsorption amount decreased. It also demonstrated that, at higher temperature, increased PFOS adsorption was mainly due to the higher diffusion rate of PFOS molecules and greater number of active sites opened on the PAC surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Carbon transfer from dissolved organic carbon to the cladoceran Bosmina: a mesocosm study

    Directory of Open Access Journals (Sweden)

    Tang Yali

    2017-01-01

    Full Text Available A mesocosm study illuminated possible transfer pathways for dissolved organic carbon from the water column to zooplankton. Organic carbon was added as 13C enriched glucose to 15 mesocosms filled with natural lake water. Stable isotope analysis and phospholipid fatty acids-based stable isotope probing were used to trace the incorporation of 13C into the cladoceran Bosmina and its potential food items. Glucose-C was shown to be assimilated into phytoplankton (including fungi and heterotrophic protists, bacteria and Bosmina, all of which became enriched with 13C during the experiment. The study suggests that bacteria play an important role in the transfer of glucose-C to Bosmina. Furthermore, osmotic algae, fungi and heterotrophic protists might also contribute to the isotopic signature changes observed in Bosmina. These findings help to clarify the contribution of dissolved organic carbon to zooplankton and its potential pathways.

  16. ORCHIDEE-SOM: modeling soil organic carbon (SOC) and dissolved organic carbon (DOC) dynamics along vertical soil profiles in Europe

    Science.gov (United States)

    Camino-Serrano, Marta; Guenet, Bertrand; Luyssaert, Sebastiaan; Ciais, Philippe; Bastrikov, Vladislav; De Vos, Bruno; Gielen, Bert; Gleixner, Gerd; Jornet-Puig, Albert; Kaiser, Klaus; Kothawala, Dolly; Lauerwald, Ronny; Peñuelas, Josep; Schrumpf, Marion; Vicca, Sara; Vuichard, Nicolas; Walmsley, David; Janssens, Ivan A.

    2018-03-01

    Current land surface models (LSMs) typically represent soils in a very simplistic way, assuming soil organic carbon (SOC) as a bulk, and thus impeding a correct representation of deep soil carbon dynamics. Moreover, LSMs generally neglect the production and export of dissolved organic carbon (DOC) from soils to rivers, leading to overestimations of the potential carbon sequestration on land. This common oversimplified processing of SOC in LSMs is partly responsible for the large uncertainty in the predictions of the soil carbon response to climate change. In this study, we present a new soil carbon module called ORCHIDEE-SOM, embedded within the land surface model ORCHIDEE, which is able to reproduce the DOC and SOC dynamics in a vertically discretized soil to 2 m. The model includes processes of biological production and consumption of SOC and DOC, DOC adsorption on and desorption from soil minerals, diffusion of SOC and DOC, and DOC transport with water through and out of the soils to rivers. We evaluated ORCHIDEE-SOM against observations of DOC concentrations and SOC stocks from four European sites with different vegetation covers: a coniferous forest, a deciduous forest, a grassland, and a cropland. The model was able to reproduce the SOC stocks along their vertical profiles at the four sites and the DOC concentrations within the range of measurements, with the exception of the DOC concentrations in the upper soil horizon at the coniferous forest. However, the model was not able to fully capture the temporal dynamics of DOC concentrations. Further model improvements should focus on a plant- and depth-dependent parameterization of the new input model parameters, such as the turnover times of DOC and the microbial carbon use efficiency. We suggest that this new soil module, when parameterized for global simulations, will improve the representation of the global carbon cycle in LSMs, thus helping to constrain the predictions of the future SOC response to global

  17. Soil organic carbon assessments in cropping systems using isotopic techniques

    Science.gov (United States)

    Martín De Dios Herrero, Juan; Cruz Colazo, Juan; Guzman, María Laura; Saenz, Claudio; Sager, Ricardo; Sakadevan, Karuppan

    2016-04-01

    Introduction of improved farming practices are important to address the challenges of agricultural production, food security, climate change and resource use efficiency. The integration of livestock with crops provides many benefits including: (1) resource conservation, (2) ecosystem services, (3) soil quality improvements, and (4) risk reduction through diversification of enterprises. Integrated crop livestock systems (ICLS) with the combination of no-tillage and pastures are useful practices to enhance soil organic carbon (SOC) compared with continuous cropping systems (CCS). In this study, the SOC and its fractions in two cropping systems namely (1) ICLS, and (2) CCS were evaluated in Southern Santa Fe Province in Argentina, and the use of delta carbon-13 technique and soil physical fractionation were evaluated to identify sources of SOC in these systems. Two farms inside the same soil cartographic unit and landscape position in the region were compared. The ICLS farm produces lucerne (Medicago sativa Merrill) and oat (Avena sativa L.) grazed by cattle alternatively with grain summer crops sequence of soybean (Glicine max L.) and corn (Zea mays L.), and the farm under continuous cropping system (CCS) produces soybean and corn in a continuous sequence. The soil in the area is predominantly a Typic Hapludoll. Soil samples from 0-5 and 0-20 cm depths (n=4) after the harvest of grain crops were collected in each system and analyzed for total organic carbon (SOC, 0-2000 μm), particulate organic carbon (POC, 50-100 μm) and mineral organic carbon (MOC, is probably due to the presence of deep roots under pastures in ICLS. Delta carbon-13 values for 0-5 cm were -22.9, -21.2 and -19.9 per mil for REF, ICLS and CCS, respectively (Pis explained by the presence of tree species with high lignin content in natural vegetation. Lignin has lower delta carbon-13 compared to cellulose (dominating in crops and pastures), which is present in greater proportion in plant residues of

  18. Comparison of carbon onions and carbon blacks as conductive additives for carbon supercapacitors in organic electrolytes

    Science.gov (United States)

    Jäckel, N.; Weingarth, D.; Zeiger, M.; Aslan, M.; Grobelsek, I.; Presser, V.

    2014-12-01

    This study investigates carbon onions (∼400 m2 g-1) as a conductive additive for supercapacitor electrodes of activated carbon and compares their performance with carbon black with high or low internal surface area. We provide a study of the electrical conductivity and electrochemical behavior between 2.5 and 20 mass% addition of each of these three additives to activated carbon. Structural characterization shows that the density of the resulting film electrodes depends on the degree of agglomeration and the amount of additive. Addition of low surface area carbon black (∼80 m2 g-1) enhances the power handling of carbon electrodes but significantly lowers the specific capacitance even when adding small amounts of carbon black. A much lower decrease in specific capacitance is observed for carbon onions and the best values are seen for carbon black with a high surface area (∼1390 m2 g-1). The overall performance benefits from the addition of any of the studied additives only at either high scan rates and/or electrolytes with high ion mobility. Normalization to the volume shows a severe decrease in volumetric capacitance and only at high current densities nearing 10 A g-1 we can see an improvement of the electrode capacitance.

  19. Aged riverine particulate organic carbon in four UK catchments

    International Nuclear Information System (INIS)

    Adams, Jessica L.; Tipping, Edward; Bryant, Charlotte L.; Helliwell, Rachel C.; Toberman, Hannah; Quinton, John

    2015-01-01

    The riverine transport of particulate organic matter (POM) is a significant flux in the carbon cycle, and affects macronutrients and contaminants. We used radiocarbon to characterise POM at 9 riverine sites of four UK catchments (Avon, Conwy, Dee, Ribble) over a one-year period. High-discharge samples were collected on three or four occasions at each site. Suspended particulate matter (SPM) was obtained by centrifugation, and the samples were analysed for carbon isotopes. Concentrations of SPM and SPM organic carbon (OC) contents were also determined, and were found to have a significant negative correlation. For the 7 rivers draining predominantly rural catchments, PO 14 C values, expressed as percent modern carbon absolute (pMC), varied little among samplings at each site, and there was no significant difference in the average values among the sites. The overall average PO 14 C value for the 7 sites of 91.2 pMC corresponded to an average age of 680 14 C years, but this value arises from the mixing of differently-aged components, and therefore significant amounts of organic matter older than the average value are present in the samples. Although topsoil erosion is probably the major source of the riverine POM, the average PO 14 C value is appreciably lower than topsoil values (which are typically 100 pMC). This is most likely explained by inputs of older subsoil OC from bank erosion, or the preferential loss of high- 14 C topsoil organic matter by mineralisation during riverine transport. The significantly lower average PO 14 C of samples from the River Calder (76.6 pMC), can be ascribed to components containing little or no radiocarbon, derived either from industrial sources or historical coal mining, and this effect is also seen in the River Ribble, downstream of its confluence with the Calder. At the global scale, the results significantly expand available information for PO 14 C in rivers draining catchments with low erosion rates. - Highlights:

  20. Aged riverine particulate organic carbon in four UK catchments

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Jessica L., E-mail: jesams@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster, LA1 4AP (United Kingdom); Tipping, Edward, E-mail: et@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster, LA1 4AP (United Kingdom); Bryant, Charlotte L., E-mail: charlotte.bryant@glasgow.ac.uk [NERC Radiocarbon Facility, East Kilbride G75 0QF, Scotland (United Kingdom); Helliwell, Rachel C., E-mail: rachel.helliwell@hutton.ac.uk [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH Scotland (United Kingdom); Toberman, Hannah, E-mail: hannahtoberman@hotmail.com [Centre for Ecology and Hydrology, Lancaster Environment Centre, Lancaster, LA1 4AP (United Kingdom); School of Environmental Sciences, University of Liverpool, Liverpool L69 3GP (United Kingdom); Quinton, John, E-mail: j.quinton@lancaster.ac.uk [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2015-12-01

    The riverine transport of particulate organic matter (POM) is a significant flux in the carbon cycle, and affects macronutrients and contaminants. We used radiocarbon to characterise POM at 9 riverine sites of four UK catchments (Avon, Conwy, Dee, Ribble) over a one-year period. High-discharge samples were collected on three or four occasions at each site. Suspended particulate matter (SPM) was obtained by centrifugation, and the samples were analysed for carbon isotopes. Concentrations of SPM and SPM organic carbon (OC) contents were also determined, and were found to have a significant negative correlation. For the 7 rivers draining predominantly rural catchments, PO{sup 14}C values, expressed as percent modern carbon absolute (pMC), varied little among samplings at each site, and there was no significant difference in the average values among the sites. The overall average PO{sup 14}C value for the 7 sites of 91.2 pMC corresponded to an average age of 680 {sup 14}C years, but this value arises from the mixing of differently-aged components, and therefore significant amounts of organic matter older than the average value are present in the samples. Although topsoil erosion is probably the major source of the riverine POM, the average PO{sup 14}C value is appreciably lower than topsoil values (which are typically 100 pMC). This is most likely explained by inputs of older subsoil OC from bank erosion, or the preferential loss of high-{sup 14}C topsoil organic matter by mineralisation during riverine transport. The significantly lower average PO{sup 14}C of samples from the River Calder (76.6 pMC), can be ascribed to components containing little or no radiocarbon, derived either from industrial sources or historical coal mining, and this effect is also seen in the River Ribble, downstream of its confluence with the Calder. At the global scale, the results significantly expand available information for PO{sup 14}C in rivers draining catchments with low erosion rates

  1. Novel synthesis of magnesium hydroxide nanoparticles modified with organic phosphate and their effect on the flammability of acrylonitrile-butadiene styrene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Attia, Nour F., E-mail: drnour2005@yahoo.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Goda, Emad S.; Nour, M.A. [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt); Sabaa, M.W. [Chemistry Department, Faculty of Science, Cairo University, NahdetMisr Street, Giza 12613 (Egypt); Hassan, M.A., E-mail: Mohamed_a_hassan@hotmail.com [Fire Protection Laboratory, Chemistry Division, National Institute of Standards, 136, Giza 12211 (Egypt)

    2015-11-15

    New and facile method for the synthesis and modification of magnesium hydroxide nanoparticles has been developed. The organic phosphate was used to facilitate the synthesis and wrapping of magnesium hydroxide nanoparticles with organic phosphate shell. The size of the nanoparticles wrapped with phosphate has an average diameter range from 46 to 125 nm. The preparation method has governed the nanoparticles diameter based on reaction time. Thermal stability and morphological properties of the new nanoparticles coated phosphates were investigated. The developed magnesium hydroxide nanoparticles-organic phosphate achieved a very good compatibility when dispersed in acrylonitrile-butadiene styrene polymer (ABS) produced dispersed nanocomposites. The flammability and thermal properties of the new polymer nanocomposites were studied. The rate of burning of the nanocomposites was reduced to 9.8 mm/min compared to 15, 21.9 and 42.5 mm/min for polymer-conventional magnesium hydroxide composite, polymer-conventional magnesium hydroxide-organic phosphate composite and virgin polymer, respectively. The peak heat release rate (PHRR) and total heat release (THR) of the new nanocomposites were recorded as 243.4 kW/m{sup 2} and 19.2 MJ/m{sup 2}, respectively, achieved 71% reduction for PHRR and 55% for THR. The synergism between magnesium hydroxide nanoparticles and organic phosphates shell was also studied. The developed nanoparticles suppressed the emission of toxic gases. The different materials were characterized using thermal gravimetric analysis, fourier transform infrared spectroscopy, transmission electron microscopy. The flammability properties were evaluated using UL94 horizontal method and cone calorimeter. The dispersion of magnesium hydroxide nanoparticles-organic phosphate in ABS was studied using scanning electron microscope. - Highlights: • Novel and facile nanoparticles synthesis and modification have developed. • Magnesium hydroxide nanoparticles size has

  2. 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.

  3. Retardation of volatile organic compounds in ground water in low organic carbon sediments

    International Nuclear Information System (INIS)

    Hoffman, F.

    1995-04-01

    It is postulated that adsorption onto aquifer matrix surfaces is only one of the processes that retard contaminants in ground water in unconsolidated sediments; others include hydrodynamic dispersion, abiotic/biotic degradation, matrix diffusion, partitioning to organic carbon, diffusion into and retention in dead-end pores, etc. This work aims at these processes in defining the K d of VOCs in sediments with low organic carbon content. Experiments performed include an initial column experiment for VOC (TCE and perchloroethylene(PCE)) retardation tests on geological materials, PCE and TCE data from LLNL sediments, and a preliminary multilayer sampler experiment. The VOC K d s in low organic carbon permeable aquifer materials are dependent on the VOC composition and independent of aquifer grain size, indicating that sorption was not operative and that the primary retarding factors are diffusion controlled. The program of future experiments is described

  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. An improved method for quantitatively measuring the sequences of total organic carbon and black carbon in marine sediment cores

    Science.gov (United States)

    Xu, Xiaoming; Zhu, Qing; Zhou, Qianzhi; Liu, Jinzhong; Yuan, Jianping; Wang, Jianghai

    2018-01-01

    Understanding global carbon cycle is critical to uncover the mechanisms of global warming and remediate its adverse effects on human activities. Organic carbon in marine sediments is an indispensable part of the global carbon reservoir in global carbon cycling. Evaluating such a reservoir calls for quantitative studies of marine carbon burial, which closely depend on quantifying total organic carbon and black carbon in marine sediment cores and subsequently on obtaining their high-resolution temporal sequences. However, the conventional methods for detecting the contents of total organic carbon or black carbon cannot resolve the following specific difficulties, i.e., (1) a very limited amount of each subsample versus the diverse analytical items, (2) a low and fluctuating recovery rate of total organic carbon or black carbon versus the reproducibility of carbon data, and (3) a large number of subsamples versus the rapid batch measurements. In this work, (i) adopting the customized disposable ceramic crucibles with the microporecontrolled ability, (ii) developing self-made or customized facilities for the procedures of acidification and chemothermal oxidization, and (iii) optimizing procedures and carbon-sulfur analyzer, we have built a novel Wang-Xu-Yuan method (the WXY method) for measuring the contents of total organic carbon or black carbon in marine sediment cores, which includes the procedures of pretreatment, weighing, acidification, chemothermal oxidation and quantification; and can fully meet the requirements of establishing their highresolution temporal sequences, whatever in the recovery, experimental efficiency, accuracy and reliability of the measurements, and homogeneity of samples. In particular, the usage of disposable ceramic crucibles leads to evidently simplify the experimental scenario, which further results in the very high recovery rates for total organic carbon and black carbon. This new technique may provide a significant support for

  6. Synthesis and characterization of carbonated hydroxyapatite and bioinspired polymer-calcium phosphate nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Yusufoglu, Yusuf [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Nature offers many exciting ideas and inspiration for the development of new materials and processes. The toughness of spider silk, the strength and lightweight of bone, and the adhesion abilities of the gecko's feet are some of the many examples of highperformance natural materials, which have attracted the interest of scientist to duplicate their properties in man-made materials. Materials found in nature combine many inspiring properties such as miniaturization, sophistication, hierarchical organization, hybridization, and adaptability. In all biological systems, whether very basic or highly complex, nature provides a multiplicity of materials, architectures, systems and functions. Generally, the architectural configurations and material characteristics are the important features that have been duplicated from nature for building synthetic structural composites.

  7. A study of organic acid production in contrasts between two phosphate solubilizing fungi: Penicillium oxalicum and Aspergillus niger

    Science.gov (United States)

    Li, Zhen; Bai, Tongshuo; Dai, Letian; Wang, Fuwei; Tao, Jinjin; Meng, Shiting; Hu, Yunxiao; Wang, Shimei; Hu, Shuijin

    2016-04-01

    Phosphate solubilizing fungi (PSF) have huge potentials in enhancing release of phosphorus from fertilizer. Two PSF (NJDL-03 and NJDL-12) were isolated and identified as Penicillium oxalicum and Aspergillus niger respectively in this study. The quantification and identification of organic acids were performed by HPLC. Total concentrations of organic acids secreted by NJDL-03 and NJDL-12 are ~4000 and ~10,000 mg/L with pH values of 3.6 and 2.4 respectively after five-days culture. Oxalic acid dominates acidity in the medium due to its high concentration and high acidity constant. The two fungi were also cultured for five days with the initial pH values of the medium varied from 6.5 to 1.5. The biomass reached the maximum when the initial pH values are 4.5 for NJDL-03 and 2.5 for NJDL-12. The organic acids for NJDL-12 reach the maximum at the initial pH = 5.5. However, the acids by NJDL-03 continue to decrease and proliferation of the fungus terminates at pH = 2.5. The citric acid production increases significantly for NJDL-12 at acidic environment, whereas formic and oxalic acids decrease sharply for both two fungi. This study shows that NJDL-12 has higher ability in acid production and has stronger adaptability to acidic environment than NJDL-03.

  8. on association of trialkyl phosphates

    International Nuclear Information System (INIS)

    Petkovic, D.M.; Maksimovic, Z.B.

    1976-01-01

    The association constants of tri-n-butyl (TBP), tri-n-propyl (TPP) and triethyl phosphate (TEP) with chloroform, carbon tetrachloride and benzene were determined by dielectric constant, proton magnetic resonance and vapor pressure measurements. Correlation of the trialkyl phosphate-chloroform association constants, using the Hammett equation, showed their increase with the number of carbon atoms in the aliphatic radicals. The change of trialkyl phosphate reactivity with temperature was used to determine the thermodynamic quantities. (author)

  9. Effect of pore size distribution on iron oxide coated granular activated carbons for phosphate adsorption – Importance of mesopores

    NARCIS (Netherlands)

    Suresh Kumar, P.; Prot, T.J.F.; Korving, Leon; Keesman, Karel J.; Dugulan, A.I.; van Loosdrecht, Mark C.M.; Witkamp, G.J.

    2017-01-01

    Adsorption is often suggested for to reach very low phosphate levels in municipal wastewater effluent and even to recover phosphate. Adsorbent performance is usually associated with surface area but the exact role of the pore size distribution (PSD) is unclear. Here, we show the effect of the PSD

  10. Organic-inorganic hybrid carbon dots for cell imaging

    Science.gov (United States)

    Liu, Huan; Zhang, Hongwen; Li, Jiayu; Tang, Yuying; Cao, Yu; Jiang, Yan

    2018-04-01

    In this paper, nitrogen-doped carbon dots (CDs) had been synthesized directly by one-step ultrasonic treatment under mild conditions. During the functionalization process, Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) was used as stabilizing and passivation agent, which lead to self-assembling of CDs in aqueous medium solution. OA-POSS was obtained via hydrolytic condensation of γ-aminopropyl triethoxy silane (APTES). The average size of CDs prepared was approximately 3.3 nm with distribution between 2.5 nm and 4.5 nm. The prepared organic-inorganic hybrid carbon dots have several characteristics such as photoluminescence emission wavelength, efficient cellular uptake, and good biocompatibility. The results indicate that OA-POSS can maintain the fluorescence properties of the carbon dots effectively, and reduced cytotoxicity provides the possibility for biomedical applications. More than 89% of the Hela cells were viable when incubated with 2 mg ml‑1 or lesser organic-inorganic hybrid carbon dots. Thus, it provides a potential for multicolor imaging with HeLa cells.

  11. Dilution limits dissolved organic carbon utilization in the deep ocean

    KAUST Repository

    Arrieta, Jesus

    2015-03-19

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

  12. Dilution limits dissolved organic carbon utilization in the deep ocean

    KAUST Repository

    Arrieta, J M; Mayol, Eva; Hansman, Roberta L.; Herndl, Gerhard J.; Dittmar, Thorsten; Duarte, Carlos M.

    2015-01-01

    Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

  13. The impact of biosolids application on organic carbon and carbon dioxide fluxes in soil.

    Science.gov (United States)

    Wijesekara, Hasintha; Bolan, Nanthi S; Thangavel, Ramesh; Seshadri, Balaji; Surapaneni, Aravind; Saint, Christopher; Hetherington, Chris; Matthews, Peter; Vithanage, Meththika

    2017-12-01

    A field study was conducted on two texturally different soils to determine the influences of biosolids application on selected soil chemical properties and carbon dioxide fluxes. Two sites, located in Manildra (clay loam) and Grenfell (sandy loam), in Australia, were treated at a single level of 70 Mg ha -1 biosolids. Soil samples were analyzed for SOC fractions, including total organic carbon (TOC), labile, and non-labile carbon contents. The natural abundances of soil δ 13 C and δ 15 N were measured as isotopic tracers to fingerprint carbon derived from biosolids. An automated soil respirometer was used to measure in-situ diurnal CO 2 fluxes, soil moisture, and temperature. Application of biosolids increased the surface (0-15 cm) soil TOC by > 45% at both sites, which was attributed to the direct contribution from residual carbon in the biosolids and also from the increased biomass production. At both sites application of biosolids increased the non-labile carbon fraction that is stable against microbial decomposition, which indicated the soil carbon sequestration potential of biosolids. Soils amended with biosolids showed depleted δ 13 C, and enriched δ 15 N indicating the accumulation of biosolids residual carbon in soils. The in-situ respirometer data demonstrated enhanced CO 2 fluxes at the sites treated with biosolids, indicating limited carbon sequestration potential. However, addition of biosolids on both the clay loam and sandy loam soils found to be effective in building SOC than reducing it. Soil temperature and CO 2 fluxes, indicating that temperature was more important for microbial degradation of carbon in biosolids than soil moisture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Pyroclastic Eruption Boosts Organic Carbon Fluxes Into Patagonian Fjords

    Science.gov (United States)

    Mohr, Christian H.; Korup, Oliver; Ulloa, Héctor; Iroumé, Andrés.

    2017-11-01

    Fjords and old-growth forests store large amounts of organic carbon. Yet the role of episodic disturbances, particularly volcanic eruptions, in mobilizing organic carbon in fjord landscapes covered by temperate rainforests remains poorly quantified. To this end, we estimated how much wood and soils were flushed to nearby fjords following the 2008 eruption of Chaitén volcano in south-central Chile, where pyroclastic sediments covered >12 km2 of pristine temperate rainforest. Field-based surveys of forest biomass, soil organic content, and dead wood transport reveal that the reworking of pyroclastic sediments delivered 66,500 + 14,600/-14,500 tC of large wood to two rivers entering the nearby Patagonian fjords in less than a decade. A similar volume of wood remains in dead tree stands and buried beneath pyroclastic deposits ( 79,900 + 21,100/-16,900 tC) or stored in active river channels (5,900-10,600 tC). We estimate that bank erosion mobilized 132,300+21,700/-30,600 tC of floodplain forest soil. Eroded and reworked forest soils have been accreting on coastal river deltas at >5 mm yr-1 since the eruption. While much of the large wood is transported out of the fjord by long-shore drift, the finer fraction from eroded forest soils is likely to be buried in the fjords. We conclude that the organic carbon fluxes boosted by rivers adjusting to high pyroclastic sediment loads may remain elevated for up to a decade and that Patagonian temperate rainforests disturbed by excessive loads of pyroclastic debris can be episodic short-lived carbon sources.

  15. Hidden cycle of dissolved organic carbon in the deep ocean.

    Science.gov (United States)

    Follett, Christopher L; Repeta, Daniel J; Rothman, Daniel H; Xu, Li; Santinelli, Chiara

    2014-11-25

    Marine dissolved organic carbon (DOC) is a large (660 Pg C) reactive carbon reservoir that mediates the oceanic microbial food web and interacts with climate on both short and long timescales. Carbon isotopic content provides information on the DOC source via δ(13)C and age via Δ(14)C. Bulk isotope measurements suggest a microbially sourced DOC reservoir with two distinct components of differing radiocarbon age. However, such measurements cannot determine internal dynamics and fluxes. Here we analyze serial oxidation experiments to quantify the isotopic diversity of DOC at an oligotrophic site in the central Pacific Ocean. Our results show diversity in both stable and radio isotopes at all depths, confirming DOC cycling hidden within bulk analyses. We confirm the presence of isotopically enriched, modern DOC cocycling with an isotopically depleted older fraction in the upper ocean. However, our results show that up to 30% of the deep DOC reservoir is modern and supported by a 1 Pg/y carbon flux, which is 10 times higher than inferred from bulk isotope measurements. Isotopically depleted material turns over at an apparent time scale of 30,000 y, which is far slower than indicated by bulk isotope measurements. These results are consistent with global DOC measurements and explain both the fluctuations in deep DOC concentration and the anomalous radiocarbon values of DOC in the Southern Ocean. Collectively these results provide an unprecedented view of the ways in which DOC moves through the marine carbon cycle.

  16. Spatial Patterns of Soil Organic Carbon in the United States

    Science.gov (United States)

    Bliss, N. B.

    2005-12-01

    The Department of the Interior (DOI) has jurisdiction influencing approximately 22 percent of the land area of the United States. The poster presents estimates of the current stocks of soil organic carbon (SOC) on all lands and Federal lands. The DOI lands have about 22 percent of the nation's SOC, so the average carbon intensity (8.66 kg C m-2) about matches the average for all lands (8.81 kg C m-2). However the carbon on DOI lands is not evenly distributed. Of the 17.76 Petagrams (1 Pg = 1015 grams) of SOC on DOI lands, 13.07 Pg (74 percent) are in Alaska, and 4.69 Pg (26 percent) are in the Conterminous U.S. The Alaska soils are wetter and colder than the national average, and the DOI lands in the conterminous U.S. are warmer and drier than the average. A set of SOC maps is shown, developed by intersecting the State Soil Geographic (STATSGO) database with data on federal lands from the National Atlas. With 22 percent of the nation's soil carbon, the DOI lands are important in a national accounting of greenhouse gas emission and sequestration. Future behavior of these lands is uncertain, but in scenarios of warming or drying, carbon released by respiration may exceed carbon captured by photosynthesis, resulting in a net release of carbon to the atmosphere. If warming stimulates a net release of greenhouse gases, this represents a positive feedback contributing to future global warming, a very unstable condition for the global climate system.

  17. Storage and release of organic carbon from glaciers and ice sheets

    Science.gov (United States)

    Hood, Eran; Battin, Tom J.; Fellman, Jason; O'Neel, Shad; Spencer, Robert G. M.

    2015-02-01

    Polar ice sheets and mountain glaciers, which cover roughly 11% of the Earth's land surface, store organic carbon from local and distant sources and then release it to downstream environments. Climate-driven changes to glacier runoff are expected to be larger than climate impacts on other components of the hydrological cycle, and may represent an important flux of organic carbon. A compilation of published data on dissolved organic carbon from glaciers across five continents reveals that mountain and polar glaciers represent a quantitatively important store of organic carbon. The Antarctic Ice Sheet is the repository of most of the roughly 6 petagrams (Pg) of organic carbon stored in glacier ice, but the annual release of glacier organic carbon is dominated by mountain glaciers in the case of dissolved organic carbon and the Greenland Ice Sheet in the case of particulate organic carbon. Climate change contributes to these fluxes: approximately 13% of the annual flux of glacier dissolved organic carbon is a result of glacier mass loss. These losses are expected to accelerate, leading to a cumulative loss of roughly 15 teragrams (Tg) of glacial dissolved organic carbon by 2050 due to climate change -- equivalent to about half of the annual flux of dissolved organic carbon from the Amazon River. Thus, glaciers constitute a key link between terrestrial and aquatic carbon fluxes, and will be of increasing importance in land-to-ocean fluxes of organic carbon in glacierized regions.

  18. Storage and release of organic carbon from glaciers and ice sheets

    Science.gov (United States)

    Hood, Eran; Battin, Tom J.; Fellman, Jason; O'Neel, Shad; Spencer, Robert G. M.

    2015-01-01

    Polar ice sheets and mountain glaciers, which cover roughly 11% of the Earth's land surface, store organic carbon from local and distant sources and then release it to downstream environments. Climate-driven changes to glacier runoff are expected to be larger than climate impacts on other components of the hydrological cycle, and may represent an important flux of organic carbon. A compilation of published data on dissolved organic carbon from glaciers across five continents reveals that mountain and polar glaciers represent a quantitatively important store of organic carbon. The Antarctic Ice Sheet is the repository of most of the roughly 6 petagrams (Pg) of organic carbon stored in glacier ice, but the annual release of glacier organic carbon is dominated by mountain glaciers in the case of dissolved organic carbon and the Greenland Ice Sheet in the case of particulate organic carbon. Climate change contributes to these fluxes: approximately 13% of the annual flux of glacier dissolved organic carbon is a result of glacier mass loss. These losses are expected to accelerate, leading to a cumulative loss of roughly 15 teragrams (Tg) of glacial dissolved organic carbon by 2050 due to climate change — equivalent to about half of the annual flux of dissolved organic carbon from the Amazon River. Thus, glaciers constitute a key link between terrestrial and aquatic carbon fluxes, and will be of increasing importance in land-to-ocean fluxes of organic carbon in glacierized regions.

  19. Aqueous adsorption and removal of organic contaminants by carbon nanotubes

    International Nuclear Information System (INIS)

    Yu, Jin-Gang; Zhao, Xiu-Hui; Yang, Hua; Chen, Xiao-Hong; Yang, Qiaoqin; Yu, Lin-Yan; Jiang, Jian-Hui; Chen, Xiao-Qing

    2014-01-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future. - Highlights: • We summarize the most recent research progress of CNTs for removal of organics. • Adsorption mechanisms between CNTs and organics were elucidated in detail. • The developing trends and prospects of CNTs for removal of organics were discussed

  20. Aqueous adsorption and removal of organic contaminants by carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Jin-Gang, E-mail: yujg@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Zhao, Xiu-Hui; Yang, Hua [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Chen, Xiao-Hong [Collaborative Innovation Center of Resource-conserving and Environment-friendly Society and Ecological Civilization, Changsha, Hunan 410083 (China); Yang, Qiaoqin [Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, SK S7N 5A9 (Canada); Yu, Lin-Yan [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China); Jiang, Jian-Hui [College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082 (China); Chen, Xiao-Qing, E-mail: xqchen@csu.edu.cn [College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan 410083 (China); Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education, Central South University, Changsha, Hunan 410083 (China)

    2014-06-01

    Organic contaminants have become one of the most serious environmental problems, and the removal of organic contaminants (e.g., dyes, pesticides, and pharmaceuticals/drugs) and common industrial organic wastes (e.g., phenols and aromatic amines) from aqueous solutions is of special concern because they are recalcitrant and persistent in the environment. In recent years, carbon nanotubes (CNTs) have been gradually applied to the removal of organic contaminants from wastewater through adsorption processes. This paper reviews recent progress (145 studies published from 2010 to 2013) in the application of CNTs and their composites for the removal of toxic organic pollutants from contaminated water. The paper discusses removal efficiencies and adsorption mechanisms as well as thermodynamics and reaction kinetics. CNTs are predicted to have considerable prospects for wider application to wastewater treatment in the future. - Highlights: • We summarize the most recent research progress of CNTs for removal of organics. • Adsorption mechanisms between CNTs and organics were elucidated in detail. • The developing trends and prospects of CNTs for removal of organics were discussed.

  1. Strontium hydroxyapatite and strontium carbonate as templates for the precipitation of calcium-phosphates in the absence and presence of fluoride

    Science.gov (United States)

    Sternitzke, Vanessa; Janousch, Markus; Heeb, Michèle B.; Hering, Janet G.; Johnson, C. Annette

    2014-06-01

    The heterogeneous precipitation of calcium-phosphates on calcium hydroxyapatite (Ca10(PO4)6(OH)2 or HAP) in the presence and absence of fluoride is important in the formation of bone and teeth, protection against tooth decay, dental and skeletal fluorosis and defluoridation of drinking water. Strontium hydroxyapatite (Sr10(PO4)6(OH)2 or SrHAP) and strontium carbonate (SrCO3) were used as calcium-free seed templates in precipitation experiments conducted with varying initial calcium-to-phosphate (Ca/P) or calcium-to-phosphate-to-fluoride (Ca/P/F) ratios. Suspensions of SrHAP or SrCO3 seed templates (which were calcium-limited for both templates and phosphate-limited in the case of SrCO3) were reacted at pH 7.3 (25 °C) over 3 days. The resulting solids were examined with Scanning Transmission Electron Microscopy (STEM), X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Near Edge Structure (XANES), and Extended X-ray Absorption Fine Structure spectroscopy (EXAFS). Calcium apatite was the predominant phase identified by all techniques independent of the added Ca/P ratios and of the presence of fluoride. It was not possible to make an unambiguous distinction between HAP and fluorapatite (Ca10(PO4)6F2, FAP). The apatite was calcium-deficient and probably contained some strontium.

  2. Validity of estimating the organic carbon content of basin sediment using color measurements

    International Nuclear Information System (INIS)

    Sasaki, Toshinori; Sugai, Toshihiko; Ogami, Takashi; Yanagida, Makoto; Yasue, Ken-ichi

    2010-01-01

    Psychometric lightness (L* value) measured by a colorimeter offers a rapid means of obtaining the organic carbon content of sediment. We measured peat and lacustrine sediments covering the past 300 ka - 106 samples for L* value and 197 samples for organic carbon content. L* values are highly correlated with organic carbon contents. Therefore, L* values are a convenient alternative to measuring organic carbon contents. (author)

  3. [Effects of different cultivation patterns on soil aggregates and organic carbon fractions].

    Science.gov (United States)

    Qiu, Xiao-Lei; Zong, Liang-Gang; Liu, Yi-Fan; Du, Xia-Fei; Luo, Min; Wang, Run-Chi

    2015-03-01

    Combined with the research in an organic farm in the past 10 years, differences of soil aggregates composition, distribution and organic carbon fractions between organic and conventional cultivation were studied by simultaneous sampling analysis. The results showed that the percentages of aggregates (> 1 mm, 1-0.5 mm, 0.5-0.25 mm and organic cultivation were 9.73%, 18.41%, 24.46% and 43.90%, respectively. The percentage of organic cultivation than that in conventional cultivation. Organic cultivation increased soil organic carbon (average of 17.95 g x kg(-1)) and total nitrogen contents (average of 1.51 g x kg(-1)). Among the same aggregates in organic cultivation, the average content of heavy organic carbon fraction was significantly higher than that in conventional cultivation. This fraction accumulated in organic carbon. In organic cultivation, the content of labile organic carbon in > 1 mm macro-aggregates was significantly higher than that in conventional cultivation, while no significant difference was found among the other aggregates, indicating that the labile organic carbon was enriched in > 1 mm macro-aggregates. Organic cultivation increased the amounts of organic carbon and its fractions, reduced tillage damage to aggregates, and enhanced the stability of organic carbon. Organic cultivation was therefore beneficial for soil carbon sequestration. The findings of this research may provide theoretical basis for further acceleration of the organic agriculture development.

  4. 2,3-diphosphoglycerate, nucleotide phosophate, and organic and inorganic phosphate levels during the early phases of diabetic ketoacidosis.

    Science.gov (United States)

    Kanter, Y; Gerson, J R; Bessman, A N

    1977-05-01

    The relation between serum and red blood cell (RBC) inorganic phosphate levels, RBC 2,3-diphosphoglycerate (2,3-DPG) levels, RBC nucleotide phosphate (Pn), and RBC total phosphate (Pt) levels were studied during the early phases of treatment and recovery from diabetic ketoacidosis (DKA). A steady drop in serum inorganic phosphate was found during the first 24 hours of insulin treatment and was most profound at 24 hours. No statistically significant changes (P less than 0.05) were found in red cell inorganic phosphate or nucleotide phosphate levels during the 24-hour study period. The levels of total red cell phosphate were lower in this group of patients than in nonacidotic diabetic subjects and decreased slightly after 24 hours of treatment. The red cell 2,3-DPG levels were low at the initiation of therapy and remained low during the 24-hour study period. Glucose, bicarbonate, lactate, and ketone levels fell in linear patterns with treatment. In view of the current evidence for the effects of low 2,3-DPG on oxygen delivery and the relation of low serum phosphate levels to RBC glycolysis and 2,3-DPG formation, this study reemphasizes the need for phosphate replacement during the early phases of treatment of DKA.

  5. Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials

    CERN Document Server

    Levitsky, Igor A; Karachevtsev, Victor A

    2012-01-01

    Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials describes physical, optical and spectroscopic properties of the emerging class of nanocomposites formed from carbon nanotubes (CNTs)  interfacing with organic and inorganic materials. The three main chapters detail novel trends in  photophysics related to the interaction of  light with various carbon nanotube composites from relatively simple CNT/small molecule assemblies to complex hybrids such as CNT/Si and CNT/DNA nanostructures.   The latest experimental results are followed up with detailed discussions and scientific and technological perspectives to provide a through coverage of major topics including: ·   Light harvesting, energy conversion, photoinduced charge separation  and transport  in CNT based nanohybrids · CNT/polymer composites exhibiting photoactuation; and ·         Optical  spectroscopy  and structure of CNT/DNA complexes. Including original data and a short review of recent research, Phot...

  6. Distribution of soil organic carbon in the conterminous United States

    Science.gov (United States)

    Bliss, Norman B.; Waltman, Sharon; West, Larry T.; Neale, Anne; Mehaffey, Megan; Hartemink, Alfred E.; McSweeney, Kevin M.

    2014-01-01

    The U.S. Soil Survey Geographic (SSURGO) database provides detailed soil mapping for most of the conterminous United States (CONUS). These data have been used to formulate estimates of soil carbon stocks, and have been useful for environmental models, including plant productivity models, hydrologic models, and ecological models for studies of greenhouse gas exchange. The data were compiled by the U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) from 1:24,000-scale or 1:12,000-scale maps. It was found that the total soil organic carbon stock in CONUS to 1 m depth is 57 Pg C and for the total profile is 73 Pg C, as estimated from SSURGO with data gaps filled from the 1:250,000-scale Digital General Soil Map. We explore the non-linear distribution of soil carbon on the landscape and with depth in the soil, and the implications for sampling strategies that result from the observed soil carbon variability.

  7. Organic carbon in glacial fjords of Chilean Patagonia

    Science.gov (United States)

    Pantoja, Silvio; Gutiérrez, Marcelo; Tapia, Fabián; Abarzúa, Leslie; Daneri, Giovanni; Reid, Brian; Díez, Beatriz

    2016-04-01

    The Southern Ice Field in Chilean Patagonia is the largest (13,000 km2) temperate ice mass in the Southern hemisphere, yearly transporting ca. 40 km3 of freshwater to fjords. This volume of fresh and cold water likely affects adjacent marine ecosystems by changing circulation, productivity, food web dynamics, and the abundance and distribution of planktonic and benthic organisms. We hypothesize that freshwater-driven availability of inorganic nutrient and transport of organic and inorganic suspended matter, as well as microbes, become a controlling factor for productivity in the fjord associated with the Baker river and Jorge Montt glacier. Both appear to be sources of silicic acid, but not of nitrate and particulate organic carbon, especially during summer, when surface PAR and glacier thawing are maximal. In contrast to Baker River, the Jorge Montt glacier is also a source of dissolved organic carbon towards a proglacial fjord and the Baker Channel, indicating that a thorough chemical description of sources (tidewater glacier and glacial river) is needed. Nitrate in fiord waters reaches ca. 15 μM at 25 m depth with no evidence of mixing up during summer. Stable isotope composition of particulate organic nitrogen reaches values as low as 3 per mil in low-salinity waters near both glacier and river. Nitrogen fixation could be depleting δ15N in organic matter, as suggested by the detection at surface waters of nif H genes belonging to diazotrophs near the Montt glacier. As diazotrophs have also been detected in other cold marine waters (e.g. Baltic Sea, Arctic Ocean) as well as glaciers and polar terrestrial waters, there is certainly a potential for both marine and freshwater microbes to contribute and have a significant impact on the Patagonian N and C budgets. Assessing the impact of freshwater on C and N fluxes and the microbial community structure in Patagonian waters will allow understanding future scenarios of rapid glacier melting. This research was funded

  8. Pre-treatment of Dairy and Breast Milk with Sevelamer Hydrochloride and Sevelamer Carbonate to Reduce Phosphate.

    NARCIS (Netherlands)

    Raaijmakers, R.; Houkes, L.M.; Schroder, C.H.; Willems, J.L.; Monnens, L.A.H.

    2013-01-01

    Introduction: Young children and infants with chronic kidney disease are at increased risk of hyperphosphatemia because of high intake of dairy products. Hyperphosphatemia leads to metastatic calcifications and an increased risk of cardiovascular complications. Sevelamer is an effective phosphate

  9. Microchannel conductivity measurements in microchip for on line monitoring of dephosphorylation rates of organic phosphates using paramagnetic-beads linked alkaline phosphatase.

    Science.gov (United States)

    Kechadi, Mohammed; Sotta, Bruno; Gamby, Jean

    2015-01-01

    This paper presents the use of polymer coated microelectrodes for the realtime conductivity monitoring in a microchannel photoablated through the polymer without contact. Based on this strategy, a small conductometry sensor has been developed to record in time conductivity variation when an enzymatic reaction occurs through the channel. The rate constant determination, k2, for the dephosphorylation of organic phosphate-alkaline phosphatase-superparamagnetic beads complex using chemically different substrates such as adenosine monoesterphosphate, adenosine diphosphate and adenosine triphosphate was taken as an example to demonstrate selectivity and sensivity of the detection scheme. The k2 value measured for each adenosine phosphate decreases from 39 to 30 s(-1) in proportion with the number (3, 2 and 1) of attached phosphate moiety, thus emphasizing the steric hindrance effect on kinetics. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Hydrolysis in the organic phase during the extraction of alkali metal halides and water by copper bis(2-ethylhexyl)phosphate

    International Nuclear Information System (INIS)

    Golovanov, V.I.; Kuznetsov, S.M.

    2001-01-01

    Experimental data on extraction of halides, among which are LiCl and CsCl, and water by copper di-(2-ethylhexyl)phosphate solutions in respect to hydrolysis mechanism of reaction are generalized. Copper di-(2-ethylhexyl)phosphate manifests properties of ionogen colloidal surfactant in water. Extraction of halides by copper di-(2-ethylhexyl)phosphate was shown to be visualized by the process of capsule formation in MHal molecules, as well as in hydrolyzed MOH and HHal forms of electrolyte by Cu 4 (D2EHF) 8 · hH 2 O clathrate-like micellar associates. The model of hydrolysis mechanism is not different from proposed earlier model of electrolyte extraction with their partial dissociation in organic phase [ru

  11. Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems

    OpenAIRE

    Yanamadala, Vijay

    2005-01-01

    Cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. The process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. Especially in Madrona Marsh, one of the last remaining vernal marshes in the gre...

  12. 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.

  13. Distribution of particulate organic carbon in the central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Dhople, V.M.; Wagh, A.B.

    column. At greater depths (300 m), POC concentrations increased and were similar (145 to 542 mu g 11) to those observed at surface. Deep water POC maximum was embeded within the oxygen minimum layer and was also associated with high phosphate-phosphate-phosphorus...

  14. Arabidopsis thaliana sucrose phosphate synthase (sps) genes are expressed differentially in organs and tissues, and their transcription is regulated by osmotic stress.

    Science.gov (United States)

    Solís-Guzmán, María Gloria; Argüello-Astorga, Gerardo; López-Bucio, José; Ruiz-Herrera, León Francisco; López-Meza, Joel Edmundo; Sánchez-Calderón, Lenin; Carreón-Abud, Yazmín; Martínez-Trujillo, Miguel

    2017-11-01

    Sucrose is synthesized from UDP-Glc and Fru-6-phosphate via the activity of sucrose-phosphate synthase (SPS) enzymes, which produce Suc-6-phosphate. Suc-6-phosphate is rapidly dephosphorylated by phosphatases to produce Suc and inorganic phosphate. Arabidopsis has four sps genes encoding SPS enzymes. Of these enzymes, AtSPS1F and AtSPS2F have been grouped with other dicotyledonous SPS enzymes, while AtSPS3F and AtSPS4F are included in groups with both dicotyledonous and monocotyledonous SPS enzymes. In this work, we generated Arabidopsis thaliana transformants containing the promoter region of each sps gene fused to gfp::uidA reporter genes. A detailed characterization of expression conferred by the sps promoters in organs and tissues was performed. We observed expression of AtSPS1F, AtSPS2F and AtSPS3F in the columella roots of the plants that support sucrose synthesis. Hence, these findings support the idea that sucrose synthesis occurs in the columella cells, and suggests that sucrose has a role in this tissue. In addition, the expression of AtSPS4F was identified in embryos and suggests its participation in this developmental stage. Quantitative transcriptional analysis of A. thaliana plants grown in media with different osmotic potential showed that AtSPS2F and AtSPS4F respond to osmotic stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Self-organized global control of carbon emissions

    Science.gov (United States)

    Zhao, Zhenyuan; Fenn, Daniel J.; Hui, Pak Ming; Johnson, Neil F.

    2010-09-01

    There is much disagreement concerning how best to control global carbon emissions. We explore quantitatively how different control schemes affect the collective emission dynamics of a population of emitting entities. We uncover a complex trade-off which arises between average emissions (affecting the global climate), peak pollution levels (affecting citizens’ everyday health), industrial efficiency (affecting the nation’s economy), frequency of institutional intervention (affecting governmental costs), common information (affecting trading behavior) and market volatility (affecting financial stability). Our findings predict that a self-organized free-market approach at the level of a sector, state, country or continent can provide better control than a top-down regulated scheme in terms of market volatility and monthly pollution peaks. The control of volatility also has important implications for any future derivative carbon emissions market.

  16. Satellite observation of particulate organic carbon dynamics in ...

    Science.gov (United States)

    Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical processes that influence POC sources and sinks. Using field observations and satellite ocean color products, we developed a nw multiple regression algorithm to estimate POC on the Louisiana Continental Shelf (LCS) from satellite observations. The algorithm had reliable performance with mean relative error (MRE) of ?40% and root mean square error (RMSE) of ?50% for MODIS and SeaWiFS images for POC ranging between ?80 and ?1200 mg m23, and showed similar performance for a large estuary (Mobile Bay). Substantial spatiotemporal variability in the satellite-derived POC was observed on the LCS, with high POC found on the inner shelf (satellite data with carefully developed algorithms can greatly increase

  17. [Effects of climate change on forest soil organic carbon storage: a review].

    Science.gov (United States)

    Zhou, Xiao-yu; Zhang, Cheng-yi; Guo, Guang-fen

    2010-07-01

    Forest soil organic carbon is an important component of global carbon cycle, and the changes of its accumulation and decomposition directly affect terrestrial ecosystem carbon storage and global carbon balance. Climate change would affect the photosynthesis of forest vegetation and the decomposition and transformation of forest soil organic carbon, and further, affect the storage and dynamics of organic carbon in forest soils. Temperature, precipitation, atmospheric CO2 concentration, and other climatic factors all have important influences on the forest soil organic carbon storage. Understanding the effects of climate change on this storage is helpful to the scientific management of forest carbon sink, and to the feasible options for climate change mitigation. This paper summarized the research progress about the distribution of organic carbon storage in forest soils, and the effects of elevated temperature, precipitation change, and elevated atmospheric CO2 concentration on this storage, with the further research subjects discussed.

  18. Distributions of nutrients, dissolved organic carbon and carbohydrates in the western Arctic Ocean

    Science.gov (United States)

    Wang, Deli; Henrichs, Susan M.; Guo, Laodong

    2006-09-01

    Seawater samples were collected from stations along a transect across the shelf-basin interface in the western Arctic Ocean during September 2002, and analyzed for nutrients, dissolved organic carbon (DOC), and total dissolved carbohydrate (TDCHO) constituents, including monosaccharides (MCHO) and polysaccharides (PCHO). Nutrients (nitrate, ammonium, phosphate and dissolved silica) were depleted at the surface, especially nitrate. Their concentrations increased with increasing depth, with maxima centered at ˜125 m depth within the halocline layer, then decreased with increasing depth below the maxima. Both ammonium and phosphate concentrations were elevated in shelf bottom waters, indicating a possible nutrient source from sediments, and in a plume that extended into the upper halocline waters offshore. Concentrations of DOC ranged from 45 to 85 μM and had an inverse correlation with salinity, indicating that mixing is a control on DOC concentrations. Concentrations of TDCHO ranged from 2.5 to 19 μM-C, comprising 13-20% of the bulk DOC. Higher DOC concentrations were found in the upper water column over the shelf along with higher TDCHO concentrations. Within the TDCHO pool, the concentrations of MCHO ranged from 0.4 to 8.6 μM-C, comprising 20-50% of TDCHO, while PCHO concentrations ranged from 0.5 to 13.6 μM-C, comprising 50-80% of the TDCHO. The MCHO/TDCHO ratio was low in the upper 25 m of the water column, followed by a high MCHO/TDCHO ratio between 25 and 100 m, and a low MCHO/TDCHO ratio again below 100 m. The high MCHO/TDCHO ratio within the halocline layer likely resulted from particle decomposition and associated release of MCHO, whereas the low MCHO/TDCHO (or high PCHO/TDCHO) ratio below the halocline layer could have resulted from slow decomposition and additional particulate CHO sources.

  19. Effect of tricarboxylic acid cycle regulator on carbon retention and organic component transformation during food waste composting.

    Science.gov (United States)

    Lu, Qian; Zhao, Yue; Gao, Xintong; Wu, Junqiu; Zhou, Haixuan; Tang, Pengfei; Wei, Qingbin; Wei, Zimin

    2018-05-01

    Composting is an environment friendly method to recycling organic waste. However, with the increasing concern about greenhouse gases generated in global atmosphere, it is significant to reduce the emission of carbon dioxide (CO 2 ). This study analyzes tricarboxylic acid (TCA) cycle regulators on the effect of reducing CO 2 emission, and the relationship among organic component (OC) degradation and transformation and microorganism during composting. The results showed that adding adenosine tri-phosphate (ATP) and nicotinamide adenine dinucleotide (NADH) could enhance the transformation of OC and increase the diversity of microorganism community. Malonic acid (MA) as a competitive inhibitor could decrease the emission of CO 2 by inhibiting the TCA cycle. A structural equation model was established to explore effects of different OC and microorganism on humic acid (HA) concentration during composting. Furthermore, added MA provided an environmental benefit in reducing the greenhouse gas emission for manufacture sustainable products. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons

    Science.gov (United States)

    Brooks, A. J.; Lim, Hyung-nam; Kilduff, James E.

    2012-07-01

    Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7-8.3). Experiments were performed using a suite of model aromatic compounds having a range of π-electron energy to investigate the role of π-π electron donor-acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion effects

  1. Adsorption uptake of synthetic organic chemicals by carbon nanotubes and activated carbons

    International Nuclear Information System (INIS)

    Brooks, A J; Kilduff, James E; Lim, Hyung-nam

    2012-01-01

    Carbon nanotubes (CNTs) have shown great promise as high performance materials for adsorbing priority pollutants from water and wastewater. This study compared uptake of two contaminants of interest in drinking water treatment (atrazine and trichloroethylene) by nine different types of carbonaceous adsorbents: three different types of single walled carbon nanotubes (SWNTs), three different sized multi-walled nanotubes (MWNTs), two granular activated carbons (GACs) and a powdered activated carbon (PAC). On a mass basis, the activated carbons exhibited the highest uptake, followed by SWNTs and MWNTs. However, metallic impurities in SWNTs and multiple walls in MWNTs contribute to adsorbent mass but do not contribute commensurate adsorption sites. Therefore, when uptake was normalized by purity (carbon content) and surface area (instead of mass), the isotherms collapsed and much of the CNT data was comparable to the activated carbons, indicating that these two characteristics drive much of the observed differences between activated carbons and CNT materials. For the limited data set here, the Raman D:G ratio as a measure of disordered non-nanotube graphitic components was not a good predictor of adsorption from solution. Uptake of atrazine by MWNTs having a range of lengths and diameters was comparable and their Freundlich isotherms were statistically similar, and we found no impact of solution pH on the adsorption of either atrazine or trichloroethylene in the range of naturally occurring surface water (pH = 5.7–8.3). Experiments were performed using a suite of model aromatic compounds having a range of π-electron energy to investigate the role of π–π electron donor–acceptor interactions on organic compound uptake by SWNTs. For the compounds studied, hydrophobic interactions were the dominant mechanism in the uptake by both SWNTs and activated carbon. However, comparing the uptake of naphthalene and phenanthrene by activated carbon and SWNTs, size exclusion

  2. Substantial soil organic carbon retention along floodplains of mountain streams

    Science.gov (United States)

    Sutfin, Nicholas A.; Wohl, Ellen

    2017-07-01

    Small, snowmelt-dominated mountain streams have the potential to store substantial organic carbon in floodplain sediment because of high inputs of particulate organic matter, relatively lower temperatures compared with lowland regions, and potential for increased moisture conditions. This work (i) quantifies mean soil organic carbon (OC) content along 24 study reaches in the Colorado Rocky Mountains using 660 soil samples, (ii) identifies potential controls of OC content based on soil properties and spatial position with respect to the channel, and (iii) and examines soil properties and OC across various floodplain geomorphic features in the study area. Stepwise multiple linear regression (adjusted r2 = 0.48, p sample depth, percent sand, distance from the channel, and relative elevation from the channel are significant predictors of OC content in the study area. Principle component analysis indicates limited separation between geomorphic floodplain features based on predictors of OC content. A lack of significant differences among floodplain features suggests that the systematic random sampling employed in this study can capture the variability of OC across floodplains in the study area. Mean floodplain OC (6.3 ± 0.3%) is more variable but on average greater than values in uplands (1.5 ± 0.08% to 2.2 ± 0.14%) of the Colorado Front Range and higher than published values from floodplains in other regions, particularly those of larger rivers.

  3. 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.

  4. The soil organic carbon content of anthropogenically altered organic soils effects the dissolved organic matter quality, but not the dissolved organic carbon concentrations

    Science.gov (United States)

    Frank, Stefan; Tiemeyer, Bärbel; Bechtold, Michel; Lücke, Andreas; Bol, Roland

    2016-04-01

    Dissolved organic carbon (DOC) is an important link between terrestrial and aquatic ecosystems. This is especially true for peatlands which usually show high concentrations of DOC due to the high stocks of soil organic carbon (SOC). Most previous studies found that DOC concentrations in the soil solution depend on the SOC content. Thus, one would expect low DOC concentrations in peatlands which have anthropogenically been altered by mixing with sand. Here, we want to show the effect of SOC and groundwater level on the quantity and quality of the dissolved organic matter (DOM). Three sampling sites were installed in a strongly disturbed bog. Two sites differ in SOC (Site A: 48%, Site B: 9%) but show the same mean annual groundwater level of 15 and 18 cm below ground, respectively. The SOC content of site C (11%) is similar to Site B, but the groundwater level is much lower (-31 cm) than at the other two sites. All sites have a similar depth of the organic horizon (30 cm) and the same land-use (low-intensity sheep grazing). Over two years, the soil solution was sampled bi-weekly in three depths (15, 30 and 60 cm) and three replicates. All samples were analyzed for DOC and selected samples for dissolved organic nitrogen (DON) and delta-13C and delta-15N. Despite differences in SOC and groundwater level, DOC concentrations did not differ significantly (A: 192 ± 62 mg/L, B: 163 ± 55 mg/L and C: 191 ± 97 mg/L). At all sites, DOC concentrations exceed typical values for peatlands by far and emphasize the relevance even of strongly disturbed organic soils for DOC losses. Individual DOC concentrations were controlled by the temperature and the groundwater level over the preceding weeks. Differences in DOM quality were clearer. At site B with a low SOC content, the DOC:DON ratio of the soil solution equals the soil's C:N ratio, but the DOC:DON ratio is much higher than the C:N ratio at site A. In all cases, the DOC:DON ratio strongly correlates with delta-13C. There is no

  5. Soil organic carbon sequestration and tillage systems in Mediterranean environments

    Science.gov (United States)

    Francaviglia, Rosa; Di Bene, Claudia; Marchetti, Alessandro; Farina, Roberta

    2016-04-01

    Soil carbon sequestration is of special interest in Mediterranean areas, where rainfed cropping systems are prevalent, inputs of organic matter to soils are low and mostly rely on crop residues, while losses are high due to climatic and anthropic factors such as intensive and non-conservative farming practices. The adoption of reduced or no tillage systems, characterized by a lower soil disturbance in comparison with conventional tillage, has proved to be positively effective on soil organic carbon (SOC) conservation and other physical and chemical processes, parameters or functions, e.g. erosion, compaction, ion retention and exchange, buffering capacity, water retention and aggregate stability. Moreover, soil biological and biochemical processes are usually improved by the reduction of tillage intensity. The work deals with some results available in the scientific literature, and related to field experiment on arable crops performed in Italy, Greece, Morocco and Spain. Data were organized in a dataset containing the main environmental parameters (altitude, temperature, rainfall), soil tillage system information (conventional, minimum and no-tillage), soil parameters (bulk density, pH, particle size distribution and texture), crop type, rotation, management and length of the experiment in years, initial SOCi and final SOCf stocks. Sampling sites are located between 33° 00' and 43° 32' latitude N, 2-860 m a.s.l., with mean annual temperature and rainfall in the range 10.9-19.6° C and 355-900 mm. SOC data, expressed in t C ha-1, have been evaluated both in terms of Carbon Sequestration Rate, given by [(SOCf-SOCi)/length in years], and as percentage change in comparison with the initial value [(SOCf-SOCi)/SOCi*100]. Data variability due to the different environmental, soil and crop management conditions that influence SOC sequestration and losses will be examined.

  6. Adsorption of organic contaminants by graphene nanosheets, carbon nanotubes and granular activated carbons under natural organic matter preloading conditions.

    Science.gov (United States)

    Ersan, Gamze; Kaya, Yasemin; Apul, Onur G; Karanfil, Tanju

    2016-09-15

    The effect of NOM preloading on the adsorption of phenanthrene (PNT) and trichloroethylene (TCE) by pristine graphene nanosheets (GNS) and graphene oxide nanosheet (GO) was investigated and compared with those of a single-walled carbon nanotube (SWCNT), a multi-walled carbon nanotube (MWCNT), and two coal based granular activated carbons (GACs). PNT uptake was higher than TCE by all adsorbents on both mass and surface area bases. This was attributed to the hydrophobicity of PNT. The adsorption capacities of PNT and TCE depend on the accessibility of the organic molecules to the inner regions of the adsorbent which was influenced from the molecular size of OCs. The adsorption capacities of all adsorbents decreased as a result of NOM preloading due to site competition and/or pore/interstice blockage. However, among all adsorbents, GO was generally effected least from the NOM preloading for PNT, whereas there was not observed any trend of NOM competition with a specific adsorbent for TCE. In addition, SWCNT was generally affected most from the NOM preloading for TCE and there was not any trend for PNT. The overall results indicated that the fate and transport of organic contaminants by GNSs and CNTs type of nanoadsorbents and GACs in different natural systems will be affected by water quality parameters, characteristics of adsorbent, and properties of adsorbate. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Photometric flow injection determination of phosphate on a PDMS microchip using an optical detection system assembled with an organic light emitting diode and an organic photodiode.

    Science.gov (United States)

    Liu, Rong; Ishimatsu, Ryoichi; Yahiro, Masayuki; Adachi, Chihaya; Nakano, Koji; Imato, Toshihiko

    2015-01-01

    A compact photometric detector was constructed from an organic light emitting diode (OLED) based on a europium complex, europium(diben-zoylmethanato)3(bathophenanthroline) (Eu(DBM)3bath), as the light source and an organic photodiode (OPD) fabricated from a hetero-junction of two layers of copper phthalocyanine (CuPc)/fullerene (C60) as the photo-detector on a microchip prepared from poly(dimethylsiloxan) (PDMS) and was applied to the determination of phosphate. The OLED and the OPD were fabricated by a vapor deposition method on an indium tin oxide (ITO) coated glass substrate with the following layered structure; Glass (0.7 mm)/ITO (110 nm)/4,4'-bis[N-(1-naphthyl)-N-phenyl amino]-biphenyl (α-NPD) (30 nm)/4,4'-di(N-carbazolyl)biphenyl (CBP): Eu(3+) (8 wt%, 30 nm)/bathocuproine (BCP) (30 nm)/aluminum tris(8-hydroxyquinoline) (Alq3) (25 nm)/magnesium and silver (MgAg) (100 nm)/Ag (10nm) and Glass (0.7 mm)/ITO (110 nm)/CuPc (35 nm)/C60 (50 nm)/BCP (10 nm)/Ag (50 nm), respectively. The OLED based on the europium complex emitted a sharp light at the wavelength of 612 nm with a full width at half maximum (FWHM) of 8 nm. The performance of the photometric detector assembled was evaluated based on measurements of the absorbance of different concentrations of malachite green (MG) solutions for a batch system with 1cm long path length. The molar absorptive coefficient of the MG solution, calculated from the photocurrent of the OPD, was in good agreement with the value reported in the literature. A microchip with two inlets and one outlet U-shaped channel was prepared by a conventional photolithograph method. The OLED and the OPD were configured so as to face each other through the PDMS microchip in parallel in order to align the light axis of the OLED and the OPD with the flow cell (optical path length of 5mm), which was located at the end of outlet. For the determination of phosphate, an ion-association reaction between MG and a molybdenum-phosphate complex was utilized

  8. Performance of carbon-carbon supercapacitors based on organic, aqueous and ionic liquid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Lewandowski, Andrzej; Olejniczak, Angelika; Galinski, Maciej; Stepniak, Izabela [Faculty of Chemical Technology, Poznan University of Technology, ul. Piotrowo 3, PL-60 965 Poznan (Poland)

    2010-09-01

    Properties of capacitors working with the same carbon electrodes (activated carbon cloth) and three types of electrolytes: aqueous, organic and ionic liquids were compared. Capacitors filled with ionic liquids worked at a potential difference of 3.5 V, their solutions in AN and PC were charged up to the potential difference of 3 V, classical organic systems to 2.5 V and aqueous to 1 V. Cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy were used to characterize these capacitors. The highest specific energy was recorded for the device working with ionic liquids, while the highest power is characteristic for the device filled with aqueous H{sub 2}SO{sub 4} electrolyte. Aqueous electrolytes led to energy density an order of magnitude lower in comparison to that characteristic of ionic liquids. (author)

  9. Stable carbon isotope depth profiles and soil organic carbon dynamics in the lower Mississippi Basin

    Science.gov (United States)

    Wynn, J.G.; Harden, J.W.; Fries, T.L.

    2006-01-01

    Analysis of depth trends of 13C abundance in soil organic matter and of 13C abundance from soil-respired CO2 provides useful indications of the dynamics of the terrestrial carbon cycle and of paleoecological change. We measured depth trends of 13C abundance from cropland and control pairs of soils in the lower Mississippi Basin, as well as the 13C abundance of soil-respired CO2 produced during approximately 1-year soil incubation, to determine the role of several candidate processes on the 13C depth profile of soil organic matter. Depth profiles of 13C from uncultivated control soils show a strong relationship between the natural logarithm of soil organic carbon concentration and its isotopic composition, consistent with a model Rayleigh distillation of 13C in decomposing soil due to kinetic fractionation during decomposition. Laboratory incubations showed that initially respired CO 2 had a relatively constant 13C content, despite large differences in the 13C content of bulk soil organic matter. Initially respired CO2 was consistently 13C-depleted with respect to bulk soil and became increasingly 13C-depleted during 1-year, consistent with the hypothesis of accumulation of 13C in the products of microbial decomposition, but showing increasing decomposition of 13C-depleted stable organic components during decomposition without input of fresh biomass. We use the difference between 13C / 12C ratios (calculated as ??-values) between respired CO 2 and bulk soil organic carbon as an index of the degree of decomposition of soil, showing trends which are consistent with trends of 14C activity, and with results of a two-pooled kinetic decomposition rate model describing CO2 production data recorded during 1 year of incubation. We also observed inconsistencies with the Rayleigh distillation model in paired cropland soils and reasons for these inconsistencies are discussed. ?? 2005 Elsevier B.V. All rights reserved.

  10. Effect of organic acids production and bacterial community on the possible mechanism of phosphorus solubilization during composting with enriched phosphate-solubilizing bacteria inoculation.

    Science.gov (United States)

    Wei, Yuquan; Zhao, Yue; Shi, Mingzi; Cao, Zhenyu; Lu, Qian; Yang, Tianxue; Fan, Yuying; Wei, Zimin

    2018-01-01

    Enriched phosphate-solubilizing bacteria (PSB) agent were acquired by domesticated cultivation, and inoculated into kitchen waste composting in different stages. The effect of different treatments on organic acids production, tricalcium phosphate (TCP) solubilization and their relationship with bacterial community were investigated during composting. Our results pointed out that inoculation affected pH, total acidity and the production of oxalic, lactic, citric, succinic, acetic and formic acids. We also found a strong advantage in the solubilization of TCP and phosphorus (P) availability for PSB inoculation especially in the cooling stage. Redundancy analysis and structural equation models demonstrated inoculation by different methods changed the correlation of the bacterial community composition with P fractions as well as organic acids, and strengthened the cooperative function related to P transformation among species during composting. Finally, we proposed a possible mechanism of P solubilization with enriched PSB inoculation, which was induced by bacterial community and organic acids production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Phosphate, carbonate and organic matter distribution in sediment cores off Bombay-Saurashtra coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Rao, Ch.M.

    relationship. The total phosphorus value is high in the core from the slope, almost uniform in the cores from the outer shelf and a core from the nearby basin, but poor in a core (no. 3) considered to be from a 'closed basin' within the shelf. The total...

  12. Metal immobilization by sludge-derived biochar: roles of mineral oxides and carbonized organic compartment.

    Science.gov (United States)

    Zhang, Weihua; Huang, Xinchen; Jia, Yanming; Rees, Frederic; Tsang, Daniel C W; Qiu, Rongliang; Wang, Hong

    2017-04-01

    Pyrolyzing sludge into biochar is a potentially promising recycling/disposal solution for municipal wastewater sludge, and the sludge-derived biochar (SDBC) presents an excellent sorbent for metal immobilization. As SDBC is composed of both mineral oxides and carbonized organic compartment, this study therefore compared the sorption behaviour of Pb and Zn on SDBC to those of individual and mixture of activated carbon (AC) and amorphous aluminium oxide (Al 2 O 3 ). Batch experiments were conducted at 25 and 45 °C, and the metal-loaded sorbents were artificially aged in the atmosphere for 1-60 days followed by additional sorption experiments. The Pb sorption was generally higher than Zn sorption, and the co-presence of Pb reduced Zn sorption on each studied sorbent. Higher sorption capacities were observed at 45 °C than 25 °C for SDBC and AC, while the opposite was shown for Al 2 O 3 , indicating the significance of temperature-dependent diffusion processes in SDBC and AC. Nevertheless, metal sorption was more selective on Al 2 O 3 that showed a greater affinity towards Pb over Zn under competition, correlating with the reducible fraction of sequential extraction. Furthermore, significant amounts of Pb and Zn were additionally sorbed on SDBC following 30-day ageing. The X-ray diffraction revealed the formation of metal-phosphate precipitates, while the X-ray photoelectron spectroscopy showed a larger quantity of metal-oxygen bonding after 30-day ageing of metal-loaded SDBC. The results may imply favourable long-term transformation and additional sorption capacity of SDBC. In conclusion, SDBC resembles the sorption characteristics of both organic and mineral sorbents in different aspects, presenting an appropriate material for metal immobilization during soil amendment.

  13. Investigation the Effects of Different Doses Organic Fertilizers and Phosphate Solubilizing Bacterias on Yield and Nutrient Contents in Chickpea (Cicer arietinum L.

    Directory of Open Access Journals (Sweden)

    Ferit SÖNMEZ

    2015-07-01

    Full Text Available The study was conducted to determine the effect of phosphate solubilizing bacteria (N2; Bacillus megaterium M-3, TV-6I; Cellulosimicrobium cellulans, TV-34A; Hafnia Alve, TV-69E; Acetobacter pasteurianus and TV-83F; Bacillus cereus and organic fertilizer (0, 10 and 20 ton / ha on the seed yield and nutrient content of chickpea under field conditions in 2010 and 2011 growing seasons. Phosphate solubilizing bacteria used in this study were determined by the separate investigation conducted in chamber room by using ten phosphate solubilizing bacteria and organic fertilizer (control, %5,%10. The tiral were laid out with a factorial design in randomized complete block with three replications. In this study, plant height, primary branches, secondary branches and number of pods per plant, number of seeds per pod, grain yield and biological yield and nutrient content of stem and seed were determined. According to the results of the study bacteria applications increased significantly biological and seed yield. Bacteria applications without organic fertilizer increased nutrient contents of seed and steed except cupper content. In case of inoculation with organic fertilizer provided more increases in biological and seed yields. The highest seed yield were obtained from application of 20 ton/ha + N2 (Bacillus megaterium M-3 with 1020 kg/ha and 1793 kg/ha in 2010 and 2011 years, respectively. Bacteria without organic fertilizer application were more active in terms of phosphorus uptake in both years. 

  14. Carbon Composition of Particulate Organic Carbon in the Gulf of Mexico

    Science.gov (United States)

    Rogers, K.; Montoya, J. P.; Weber, S.; Bosman, S.; Chanton, J.

    2016-02-01

    The Deepwater Horizon blowout released 5.0x1011 g C from gaseous hydrocarbons and up to 6.0x1011g C from oil into the water column. Another carbon source, adding daily to the water column, leaks from the natural hydrocarbon seeps that pepper the seafloor of the Gulf of Mexico. How much of this carbon from the DWH and natural seeps is assimilated into particulate organic carbon (POC) in the water column? We filtered seawater collected in 2010, 2012, and 2013 from seep and non-seep sites, collecting POC on 0.7µm glass microfiber filters and analyzing the POC for stable and radiocarbon isotopes. Mixing models based on carbon isotopic endmembers of methane, oil, and modern production were used to estimate the percentage of hydrocarbon incorporated into POC. Significant differences were seen between POC from shallow and deep waters and between POC collected from seep, non-seep, and blowout sites; however yearly differences were not as evident suggesting the GOM has a consistent supply of depleted carbon. Stable carbon isotopes signatures of POC in the Gulf averaged -23.7±2.5‰ for shallow samples and -26.65±2.9‰ for deep POC samples, while radiocarbon signatures averaged -100.4±146.1‰ for shallow and -394.6±197‰ for deep samples. POC in the northern Gulf are composed of 23-91% modern carbon, 2-21% methane, and 0-71% oil. Oil plays a major role in the POC composition of the GOM, especially at the natural seep GC600.

  15. Synthesis, growth, structure, mechanical and optical properties of a new semi-organic 2-methyl imidazolium dihydrogen phosphate single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Nagapandiselvi, P., E-mail: nagapandiselvip@ssn.edu.in [Department of Physics, SSN College of Engineering, Kalavakkam (India); Baby, C. [Sophisticated Analytical Instrument Facility, Indian Institute of Technology Madras, Chennai (India); Gopalakrishnan, R. [Crystal Research Lab, Department of Physics, Anna University, Chennai (India)

    2016-09-15

    Highlights: • 2MIDP crystals were grown by slow evaporation solution growth technique. • Single crystal XRD revealed self-assembled supramolecular framework. • Z scan technique is employed for third order nonlinear optical susceptibility. • Structure-property correlation is established. - Abstract: A new semi-organic compound, 2-methyl imidazolium dihydrogen phosphate (2MIDP), was prepared and good quality single crystals of 2MIDP were grown by slow evaporation solution growth technique. Crystal structure elucidated using Single crystal XRD showed that 2MIDP crystallizes in monoclinic system with P2{sub 1}/c space group. FT-IR, UV-Vis-NIR, Fluorescence and FT-NMR spectra confirm the molecular structure of 2MIDP. The UV-Vis-NIR spectra established the suitability of the compound for NLO applications. TG-DSC showed that 2MIDP is thermally stable up to 200 °C. Mechanical characteristics like hardness number (H{sub v}), stiffness constant (C{sub 11}), yield strength (σ{sub v}), fracture toughness (K{sub c}) and brittleness index (B{sub i}) were assessed using Vicker’s microhardness tester. Third order nonlinear optical properties determined from Z-scan measurement using femto and picosecond lasers showed two photon reverse saturable absorption. The enhancement of nonlinear optical properties in femto second laser, revealed the suitability of 2MIDP for optical limiting applications.

  16. In silico peptide prediction for antibody generation to recognize 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in genetically modified organisms.

    Science.gov (United States)

    Marani, Mariela M; Costa, Joana; Mafra, Isabel; Oliveira, Maria Beatriz P P; Camperi, Silvia A; Leite, José Roberto de Souza Almeida

    2015-03-01

    For the prospective immunorecognition of 5-enolpyruvylshikimate-3-phosphate synthase (CP4-EPSPS) as a biomarker protein expressed by transgenic soybean, an extensive in silico evaluation of the referred protein was performed. The main objective of this study was the selection of a set of peptides that could function as potential immunogens for the production of novel antibodies against CP4-EPSPS protein. For this purpose, the protein was in silico cleaved with trypsin/chymotrypsin and the resultant peptides were extensively analyzed for further selection of the best candidates for antibody production. The analysis enabled the successful proposal of four peptides with potential immunogenicity for their future use as screening biomarkers of genetically modified organisms. To our knowledge, this is the first attempt to select and define potential linear epitopes for the immunization of animals and, subsequently, to generate adequate antibodies for CP4-EPSPS recognition. The present work will be followed by the synthesis of the candidate peptides to be incubated in animals for antibody generation and potential applicability for the development of an immunosensor for CP4-EPSPS detection. © 2015 Wiley Periodicals, Inc.

  17. 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.

  18. HemX is required for production of 2-ketogluconate, the predominant organic anion required for inorganic phosphate solubilization by Burkholderia sp. Ha185.

    Science.gov (United States)

    Hsu, Pei-Chun Lisa; Condron, Leo; O'Callaghan, Maureen; Hurst, Mark R H

    2015-12-01

    The bacterium Burkholderia sp. Ha185 readily solubilizes inorganic phosphate by releasing the low molecular weight organic anion, 2-ketogluconate. Using random transposon mutagenesis and in silico analysis, a mutation that caused almost complete abolition of phosphate solubilization was located within hemX, which is part of the hem operon. Burkholderia sp. Ha185 HemX is a multidomain protein, predicted to encode a bifunctional uroporphyrinogen-III synthetase/uroporphyrin-III C-methyltransferase, which has not previously been implicated in phosphate solubilization. Complementation of hemX restored the ability of the mutant to solubilize phosphate in both plate and liquid cultures. Based on a combination of organic-anion profiling, quantitative polymerase chain reaction and in silico analyses, hemX was confirmed to be solely responsible for hydroxyapatite solubilization in Burkholderia sp. Ha185. It is proposed that the biosynthesis of a yet to be determined redox cofactor by HemX is the main pathway for generating 2-ketogluconate via a haem-dependent gluconate 2-dehydrogenase in Burkholderia sp. Ha185. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    . Changes in labile soil C were assessed by carbohydrate and thermal analyses of soil samples and fractions. Forest expansion on mountain grasslands caused a decrease in SOC stocks within the mineral soil. The SOC accumulation within the organic layers following forest establishment could not fully...... and thermally labile to resistant components decreased from grassland to forest successional stages, and corresponded to decreased SOC protection within stable aggregates. This PhD thesis showed that mineral SOC stocks and physically protected SOC fractions decreased following forest expansion on mountain......Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...

  20. Phosphate-Doped Carbon Black as Pt Catalyst Support: Co-catalytic Functionality for Dimethyl Ether and Methanol Electro-oxidation

    DEFF Research Database (Denmark)

    Yin, Min; Huang, Yunjie; Li, Qingfeng

    2014-01-01

    ). The supported Pt catalysts show significant improvement in catalytic activity towards the direct oxidation of methanol and DME, attributable to the enhanced adsorption and dehydrogenation of methanol and DME, as well as the presence of activated OH species in the catalysts. The latter is demonstrated......Niobium-phosphate-doped (NbP-doped) carbon blacks were prepared as the composite catalyst support for Pt nanoparticles. Functionalities of the composite include intrinsic proton conductivity, surface acidity, and interfacial synergistic interactions with methanol and dimethyl ether (DME...... to facilitate the removal of CO intermediates formed during the oxidation reactions....

  1. Assessing the Role of Dissolved Organic Phosphate on Rates of Microbial Phosphorus Cycling

    Science.gov (United States)

    Gonzalez, A. C.; Popendorf, K. J.; Duhamel, S.

    2016-02-01

    Phosphorus (P) is an element crucial to life, and it is limiting in many parts of the ocean. In oligotrophic environments, the dissolved P pool is cycled rapidly through the activity of microbes, with turnover times of several hours or less. The overarching aim of this study was to assess the flux of P from picoplankton to the dissolved pool and the role this plays in fueling rapid P cycling. To determine if specific microbial groups are responsible for significant return of P to the dissolved pool during cell lifetime, we compared the rate of cellular P turnover (cell-Pτ, the rate of cellular P uptake divided by cellular P content) to the rate of cellular biomass turnover (cellτ). High rates of P return to the dissolved pool during cell lifetime (high cell-Pτ/cellτ) indicate significant P regeneration, fueling more rapid turnover of the dissolved P pool. We hypothesized that cell-Pτ/cellτ varies widely across picoplankton groups. One factor influencing this variation may be each microbial group's relative uptake of dissolved organic phosphorus (DOP) versus dissolved inorganic phosphorus (DIP). As extracellular hydrolysis is necessary for P incorporation from DOP, this process may return more P to the dissolved pool than DIP incorporation. This leads to the question: does a picoplankton's relative uptake of DOP (versus DIP) affect the rate at which it returns phosphorus to the dissolved pool? To address this question, we compared the rate of cellular P turnover based on uptake of DOP and uptake DIP using cultured representatives of three environmentally significant picoplankton groups: Prochlorococcus, Synechococcus, and heterotrophic bacteria. These different picoplankton groups are known to take up different ratios of DOP to DIP, and may in turn make significantly different contributions to the regeneration and cycling phosphorus. These findings have implications towards our understanding of the timeframes of biogeochemical cycling of phosphorus in the

  2. Stable isotopic constraints on global soil organic carbon turnover

    Science.gov (United States)

    Wang, Chao; Houlton, Benjamin Z.; Liu, Dongwei; Hou, Jianfeng; Cheng, Weixin; Bai, Edith

    2018-02-01

    Carbon dioxide release during soil organic carbon (SOC) turnover is a pivotal component of atmospheric CO2 concentrations and global climate change. However, reliably measuring SOC turnover rates on large spatial and temporal scales remains challenging. Here we use a natural carbon isotope approach, defined as beta (β), which was quantified from the δ13C of vegetation and soil reported in the literature (176 separate soil profiles), to examine large-scale controls of climate, soil physical properties and nutrients over patterns of SOC turnover across terrestrial biomes worldwide. We report a significant relationship between β and calculated soil C turnover rates (k), which were estimated by dividing soil heterotrophic respiration rates by SOC pools. ln( - β) exhibits a significant linear relationship with mean annual temperature, but a more complex polynomial relationship with mean annual precipitation, implying strong-feedbacks of SOC turnover to climate changes. Soil nitrogen (N) and clay content correlate strongly and positively with ln( - β), revealing the additional influence of nutrients and physical soil properties on SOC decomposition rates. Furthermore, a strong (R2 = 0.76; p turnover and thereby improving predictions of multiple global change influences over terrestrial C-climate feedback.

  3. Soil salinity decreases global soil organic carbon stocks.

    Science.gov (United States)

    Setia, Raj; Gottschalk, Pia; Smith, Pete; Marschner, Petra; Baldock, Jeff; Setia, Deepika; Smith, Jo

    2013-11-01

    Saline soils cover 3.1% (397 million hectare) of the total land area of the world. The stock of soil organic carbon (SOC) reflects the balance between carbon (C) inputs from plants, and losses through decomposition, leaching and erosion. Soil salinity decreases plant productivity and hence C inputs to the soil, but also microbial activity and therefore SOC decomposition rates. Using a modified Rothamsted Carbon model (RothC) with a newly introduced salinity decomposition rate modifier and a plant input modifier we estimate that, historically, world soils that are currently saline have lost an average of 3.47 tSOC ha(-1) since they became saline. With the extent of saline soils predicted to increase in the future, our modelling suggests that world soils may lose 6.8 Pg SOC due to salinity by the year 2100. Our findings suggest that current models overestimate future global SOC stocks and underestimate net CO2 emissions from the soil-plant system by not taking salinity effects into account. From the perspective of enhancing soil C stocks, however, given the lower SOC decomposition rate in saline soils, salt tolerant plants could be used to sequester C in salt-affected areas. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Organic carbon in Hanford single-shell tank waste

    International Nuclear Information System (INIS)

    Toth, J.J.; Willingham, C.E.; Heasler, P.G.; Whitney, P.D.

    1994-07-01

    This report documents an analysis performed by Pacific Northwest Laboratory (PNL) involving the organic carbon laboratory measurement data for Hanford single-shell tanks (SSTS) obtained from a review of the laboratory analytical data. This activity was undertaken at the request of Westinghouse Hanford Company (WHC). The objective of this study is to provide a best estimate, including confidence levels, of total organic carbon (TOC) in each of the 149 SSTs at Hanford. The TOC analyte information presented in this report is useful as part of the criteria to identify SSTs for additional measurements or monitoring for the organic safety program. This report is a precursor to an investigation of TOC and moisture in Hanford SSTS, in order to provide best estimates for each together in one report. Measured laboratory data were obtained for 75 of the 149 SSTS. The data represent a thorough investigation of data from 224 tank characterization datasets, including core-sampling and process laboratory data. Liquid and solid phase TOC values were investigated by examining selected tanks with both reported TOC values in solid and liquid phases. Some relationships were noted, but there was no clustering of data or significance between the solid and liquid phases. A methodology was developed for estimating the distribution and levels of TOC in SSTs using a logarithmic scale and an analysis of variance (ANOVA) technique. The methodology grouped tanks according to waste type using the Sort On Radioactive Waste Type (SORWT) grouping method. The SORWT model categorizes Hanford SSTs into groups of tanks expected to exhibit similar characteristics based on major waste types and processing histories. The methodology makes use of laboratory data for the particular tank and information about the SORWT group of which the tank is a member. Recommendations for a simpler tank grouping strategy based on organic transfer records were made

  5. DEVELOP NEW TOTAL ORGANIC CARBON/SPECIFIC UV ...

    Science.gov (United States)

    The purpose of this project is to provide a total organic carbon (TOC)/specific ultraviolet absorbance (SUVA) method that will be used by the Office of Ground Water and Drinking Water (OGWDW) to support monitoring requirements of the Stage 2 Disinfectant/Disinfection By-products (D/DBP) Rule. The Stage 2 Rule requires that enhanced water treatment be used if the source water is high in aquatic organic matter prior to the application of a disinfectant. Disinfectants (chlorine, ozone, etc.) are used in the production of drinking water in order to reduce the risk of microbial disease. These disinfectants react with the organic material that is naturally present in the source water to form disinfection by-products (DBPs). Exposure to some of these by-products may pose a long term health risk. The number and nature of DBPs make it impossible to fully characterize all of the by-products formed during the treatment of drinking water and it is more cost effective to reduce formation of DBPs than to remove them from the water after they are formed. Two measurements (TOC and SUVA) are believed to be predictive of the amount of by-products that can be formed during the disinfection of drinking water and are considered to be surrogates for DBP precursors. SUVA is calculated as the ultraviolet absorption at 254nm (UV254) in cm-1 divided by the mg/L dissolved organic carbon (DOC) concentration (measured after filtration of the water through a 0.45um pore-diameter filte

  6. Elemental and stable isotopic approaches for studying the organic and inorganic carbon components in natural samples

    International Nuclear Information System (INIS)

    Helie, J-F

    2009-01-01

    The carbon cycle is an important part of major biogeochemical cycles. Many techniques may be used to characterize carbon amounts and sources in the environment. Here we first review the most popular techniques for the determination of organic and inorganic carbon concentrations. Decarbonatation techniques are also reviewed in details since it is often an important part of organic carbon analysis. The second part of this paper addresses the use of carbon stable isotopes to characterize organic carbon sources and processes in the environment. An overview of general stable isotopes background and terminology is given as well as the most popular analytical techniques.

  7. Soil carbon dynamics inferred from carbon isotope compositions of soil organic matter and soil respiration

    International Nuclear Information System (INIS)

    Koarashi, Jun; Asano, Tomohiro; Iida, Takao; Moriizumi, Jun

    2004-01-01

    To better understand 14 C cycling in terrestrial ecosystems, 14 C abundances were evaluated for fractionated soil organic matter (SOM) and soil respiration in an urban forest. In 2001 soil profile, Δ 14 C values of litter and bulk SOM increased rapidly from litter surface (62.7 per mille) to uppermost mineral soil layer (244.9 per mille), and then decreased sharply to 6 cm depth of mineral soil (125.0 per mille). Carbon enriched in 14 C by atmospheric nuclear weapons testing had penetrated to at least 16 cm depth of mineral soil. The average Δ 14 C in atmospheric CO 2 was 58.8 per mille in August 2001, suggesting recent carbon input to the topmost litter layer. Although a similar depth distribution was observed for Δ 14 C values of residual SOM after acid hydrolysis, the Δ 14 C values were slightly lower than those in bulk SOM. This indicates input of 'bomb' C into this organic fraction and higher 14 C abundance in acid-soluble SOM. The most of CO 2 may be derived from the microbial decomposition of the acid-soluble, or labile, SOM. Therefore, the labile SOM may become most influential pool for soil carbon cycling. In contrast, carbon in base-insoluble SOM remained considerably low in 14 C abundance at all depths, suggesting no or little incorporation of 'bomb' C to this fraction. Values of Δ 14 C in soil respiration ranged from 91.9 to 146.4 per mille in August 2001, showing a significant contribution from decomposition of SOM fixed over past 2-40 years. These results indicate that the use of bulk SOM as a representative of soil carbon pool would lead to severe misunderstand of the soil C dynamics on decadal and shorter time scales. (author)

  8. Effect of humic substances on the precipitation of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    SONG Yong-hui; Hermann H. HAHN; Erhard HOFFMANN; Peter G. WEIDLER

    2006-01-01

    For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0,the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤ 3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.

  9. Dissolved organic carbon and its potential predictors in eutrophic lakes.

    Science.gov (United States)

    Toming, Kaire; Kutser, Tiit; Tuvikene, Lea; Viik, Malle; Nõges, Tiina

    2016-10-01

    Understanding of the true role of lakes in the global carbon cycle requires reliable estimates of dissolved organic carbon (DOC) and there is a strong need to develop remote sensing methods for mapping lake carbon content at larger regional and global scales. Part of DOC is optically inactive. Therefore, lake DOC content cannot be mapped directly. The objectives of the current study were to estimate the relationships of DOC and other water and environmental variables in order to find the best proxy for remote sensing mapping of lake DOC. The Boosted Regression Trees approach was used to clarify in which relative proportions different water and environmental variables determine DOC. In a studied large and shallow eutrophic lake the concentrations of DOC and coloured dissolved organic matter (CDOM) were rather high while the seasonal and interannual variability of DOC concentrations was small. The relationships between DOC and other water and environmental variables varied seasonally and interannually and it was challenging to find proxies for describing seasonal cycle of DOC. Chlorophyll a (Chl a), total suspended matter and Secchi depth were correlated with DOC and therefore are possible proxies for remote sensing of seasonal changes of DOC in ice free period, while for long term interannual changes transparency-related variables are relevant as DOC proxies. CDOM did not appear to be a good predictor of the seasonality of DOC concentration in Lake Võrtsjärv since the CDOM-DOC coupling varied seasonally. However, combining the data from Võrtsjärv with the published data from six other eutrophic lakes in the world showed that CDOM was the most powerful predictor of DOC and can be used in remote sensing of DOC concentrations in eutrophic lakes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Phosphorus and uranium recovery process from phosphated rocks

    Energy Technology Data Exchange (ETDEWEB)

    Sze, M C.Y.; Long, R H

    1981-01-30

    Improvement of uranium recovery in phosphate rocks by treatment with nitric acid avoiding the formation of a precipitate including a part of the uranium. The separation of uranium from phosphoric acid is obtained by liquid-liquid extraction using dialkyl posphoric acid with at least 10 carbon atoms and a phosphoryl alkyl alkoxy compound with at least 10 carbon atoms and a non water miscible organic solvent.

  11. Estimating soil labile organic carbon and potential turnover rates using a sequential fumigation–incubation procedure.

    Science.gov (United States)

    X.M. Zoua; H.H. Ruanc; Y. Fua; X.D. Yanga; L.Q. Sha

    2005-01-01

    Labile carbon is the fraction of soil organic carbon with most rapid turnover times and its oxidation drives the flux of CO2 between soils and atmosphere. Available chemical and physical fractionation methods for estimating soil labile organic carbon are indirect and lack a clear biological definition. We have modified the well-established Jenkinson and Powlson’s...

  12. Sorption of organic compounds to activated carbons. Evaluation of isotherm models

    NARCIS (Netherlands)

    Pikaar, I.; Koelmans, A.A.; Noort, van P.C.M.

    2006-01-01

    Sorption to 'hard carbon' (black carbon, coal, kerogen) in soils and sediments is of major importance for risk assessment of organic pollutants. We argue that activated carbon (AC) may be considered a model sorbent for hard carbon. Here, we evaluate six sorption models on a literature dataset for

  13. Digital Mapping of Soil Organic Carbon Contents and Stocks in Denmark

    DEFF Research Database (Denmark)

    Adhikari, Kabindra; Hartemink, Alfred E.; Minasny, Budiman

    2014-01-01

    Estimation of carbon contents and stocks are important for carbon sequestration, greenhouse gas emissions and national carbon balance inventories. For Denmark, we modeled the vertical distribution of soil organic carbon (SOC) and bulk density, and mapped its spatial distribution at five standard ...

  14. Climate Variability, Dissolved Organic Carbon, UV Exposure, and Amphibian Decline

    Science.gov (United States)

    Brooks, P. D.; O'Reilly, C. M.; Diamond, S.; Corn, S.; Muths, E.; Tonnessen, K.; Campbell, D. H.

    2001-12-01

    Increasing levels of UV radiation represent a potential threat to aquatic organisms in a wide range of environments, yet controls on in situ variability on UV exposure are relatively unknown. The primary control on the penetration of UV radiation in surface water environments is the amount of photoreactive dissolved organic carbon (DOC). Consequently, biogeochemical processes that control the cycling of DOC also affect the exposure of aquatic organisms to UV radiation. Three years of monitoring UV extinction and DOC composition in Rocky Mountain, Glacier, Sequoia/ Kings Canyon, and Olympic National Parks demonstrate that the amount of fulvic acid DOC is much more important than the total DOC pool in controlling UV attenuation. This photoreactive component of DOC originates primarily in soil, and is subject both to biogeochemical controls (e.g. temperature, moisture, vegetation, soil type) on production, and hydrologic controls on transport to surface water and consequently UV exposure to aquatic organisms. Both of these controls are positively related to precipitation with greater production and transport associated with higher precipitation amounts. For example, an approximately 20 percent reduction in precipitation from 1999 to 2000 resulted in a 27% - 59% reduction in the amount of photoreactive DOC at three sites in Rocky Mountain National Park. These differences in the amount of hydrophobic DOC result in an increase in UV exposure in the aquatic environment by a factor of 2 or more. Implications of these findings for observed patterns of amphibian decline will be discussed.

  15. Effect of carbonation on the leaching of organic carbon and of copper from MSWI bottom ash.

    Science.gov (United States)

    Arickx, S; De Borger, V; Van Gerven, T; Vandecasteele, C

    2010-07-01

    In Flanders, the northern part of Belgium, about 31% of the produced amount of MSWI bottom ash is recycled as secondary raw material. In view of recycling a higher percentage of bottom ash, a particular bottom ash fraction (Ø 0.1-2mm) was studied. As the leaching of this bottom ash fraction exceeds some of the Flemish limit values for heavy metals (with Cu being the most critical), treatment is required. Natural weathering and accelerated carbonation resulted in a significant decrease of the Cu leaching. Natural weathering during 3 months caused a decrease of Cu leaching to <50% of its original value, whereas accelerated carbonation resulted in an even larger decrease (to ca. 13% of its initial value) after 2 weeks, with the main decrease taking place within the first 48 h. Total organic carbon decreased to ca. 70% and 55% of the initial concentration in the solid phase, and to 40% and 25% in the leachate after natural weathering and after accelerated carbonation, respectively. In the solid material the decrease of the Hy fraction was the largest, the FA concentration remained essentially constant. The decrease of FA in the leachate can be attributed partly to an enhanced adsorption of FA to Fe/Al (hydr)oxides, due to the combined effect of a pH decrease and the neoformation of Al (hydr)oxides (both due to carbonation). A detailed study of adsorption of FA to Fe/Al (hydr)oxides showed that significant adsorption of FA occurs, that it increases with decreasing pH and started above pH 12 for Fe (hydr)oxides and around 10 for Al (hydr)oxides. Depending whether FA or Hy are considered the controlling factor in enhanced Cu leaching, the decreasing FA or Hy in the leachate explains the decrease in the Cu leaching during carbonation. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. Effect of surface treatment of pigment particles with polypyrrole and polyaniline phosphate on their corrosion inhibiting properties in organic coatings

    Czech Academy of Sciences Publication Activity Database

    Kalendová, A.; Veselý, D.; Kohl, M.; Stejskal, Jaroslav

    2014-01-01

    Roč. 77, č. 9 (2014), s. 1465-1483 ISSN 0300-9440 Institutional support: RVO:61389013 Keywords : conductive polymer * polypyrrole * polyaniline phosphate Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.358, year: 2014

  17. Evaluation of dispersion methods for enumeration of microorganisms from peat and activated carbon biofilters treating volatile organic compounds.

    Science.gov (United States)

    Khammar, Nadia; Malhautier, Luc; Degrange, Valérie; Lensi, Robert; Fanlo, Jean-Louis

    2004-01-01

    To enumerate microorganisms having colonized biofilters treating volatile organic compounds, it is necessary firstly to evaluate dispersion methods. Crushing, shaking and sonication were then tested for the removal of microflora from biofilters packing materials (peat and activated carbon). Continuous or discontinuous procedures, and addition of glass beads had no effect on the number of microorganisms removed from peat particles. The duration of treatment also had no effect for shaking and crushing, but the number of microorganisms after 60 min of treatment with ultrasound was significantly higher than that obtained after 0.5 min. The comparison between these methods showed that crushing was the most efficient for the removal of microorganisms from both peat and activated carbon. The comparison between three chemical dispersion agents showed that 1% Na-pyrophosphate was less efficient, compared with 200 mM phosphate buffer or 1% Na-hexametaphosphate. To optimize the cultivation of microorganisms, three different agar media were compared. Tryptic soy agar tenfold diluted (TSA 1/10) was the most suitable medium for the culture of microflora from a peat biofilter. For the activated carbon biofilter, there was no significant difference between Luria Bertoni, TSA 1/10, and plate count agar. The optimized extraction and enumeration protocols were used to perform a quantitative characterization of microbial populations in an operating laboratory activated carbon biofilter and in two parallel peat biofilters.

  18. Modelling and mapping the topsoil organic carbon content for Tanzania

    Science.gov (United States)

    Kempen, Bas; Kaaya, Abel; Ngonyani Mhaiki, Consolatha; Kiluvia, Shani; Ruiperez-Gonzalez, Maria; Batjes, Niels; Dalsgaard, Soren

    2014-05-01

    Soil organic carbon (SOC), held in soil organic matter, is a key indicator of soil health and plays an important role in the global carbon cycle. The soil can act as a net source or sink of carbon depending on land use and management. Deforestation and forest degradation lead to the release of vast amounts of carbon from the soil in the form of greenhouse gasses, especially in tropical countries. Tanzania has a high deforestation rate: it is estimated that the country loses 1.1% of its total forested area annually. During 2010-2013 Tanzania has been a pilot country under the UN-REDD programme. This programme has supported Tanzania in its initial efforts towards reducing greenhouse gas emission from forest degradation and deforestation and towards preserving soil carbon stocks. Formulation and implementation of the national REDD strategy requires detailed information on the five carbon pools among these the SOC pool. The spatial distribution of SOC contents and stocks was not available for Tanzania. The initial aim of this research, was therefore to develop high-resolution maps of the SOC content for the country. The mapping exercise was carried out in a collaborative effort with four Tanzanian institutes and data from the Africa Soil Information Service initiative (AfSIS). The mapping exercise was provided with over 3200 field observations on SOC from four sources; this is the most comprehensive soil dataset collected in Tanzania so far. The main source of soil samples was the National Forest Monitoring and Assessment (NAFORMA). The carbon maps were generated by means of digital soil mapping using regression-kriging. Maps at 250 m spatial resolution were developed for four depth layers: 0-10 cm, 10-20 cm, 20-30 cm, and 0-30 cm. A total of 37 environmental GIS data layers were prepared for use as covariates in the regression model. These included vegetation indices, terrain parameters, surface temperature, spectral reflectances, a land cover map and a small

  19. Fractionation between inorganic and organic carbon during the Lomagundi (2.22 2.1 Ga) carbon isotope excursion

    Science.gov (United States)

    Bekker, A.; Holmden, C.; Beukes, N. J.; Kenig, F.; Eglinton, B.; Patterson, W. P.

    2008-07-01

    The Lomagundi (2.22-2.1 Ga) positive carbon isotope excursion in shallow-marine sedimentary carbonates has been associated with the rise in atmospheric oxygen, but subsequent studies have demonstrated that the carbon isotope excursion was preceded by the rise in atmospheric oxygen. The amount of oxygen released to the exosphere during the Lomagundi excursion is constrained by the average global fractionation between inorganic and organic carbon, which is poorly characterized. Because dissolved inorganic and organic carbon reservoirs were arguably larger in the Paleoproterozoic ocean, at a time of lower solar luminosity and lower ocean redox state, decoupling between these two variables might be expected. We determined carbon isotope values of carbonate and organic matter in carbonates and shales of the Silverton Formation, South Africa and in the correlative Sengoma Argillite Formation, near the border in Botswana. These units were deposited between 2.22 and 2.06 Ga along the margin of the Kaapvaal Craton in an open-marine deltaic setting and experienced lower greenschist facies metamorphism. The prodelta to offshore marine shales are overlain by a subtidal carbonate sequence. Carbonates exhibit elevated 13C values ranging from 8.3 to 11.2‰ vs. VPDB consistent with deposition during the Lomagundi positive excursion. The total organic carbon (TOC) contents range from 0.01 to 0.6% and δ13C values range from - 24.8 to - 13.9‰. Thus, the isotopic fractionation between organic and carbonate carbon was on average 30.3 ± 2.8‰ ( n = 32) in the shallow-marine environment. The underlying Sengoma shales have highly variable TOC contents (0.14 to 21.94%) and δ13C values (- 33.7 to - 20.8‰) with an average of - 27.0 ± 3.0‰ ( n = 50). Considering that the shales were also deposited during the Lomagundi excursion, and taking δ13C values of the overlying carbonates as representative of the δ13C value of dissolved inorganic carbon during shale deposition, a carbon

  20. Soil organic carbon of an intensively reclaimed region in China: Current status and carbon sequestration potential.

    Science.gov (United States)

    Deng, Xunfei; Zhan, Yu; Wang, Fei; Ma, Wanzhu; Ren, Zhouqiao; Chen, Xiaojia; Qin, Fangjin; Long, Wenli; Zhu, Zhenling; Lv, Xiaonan

    2016-09-15

    Land reclamation has been highly intensive in China, resulting in a large amount of soil organic carbon (SOC) loss to the atmosphere. Evaluating the factors which drive SOC dynamics and carbon sequestration potential in reclaimed land is critical for improving soil fertility and mitigating global warming. This study aims to determine the current status and factors important to the SOC density in a typical reclaimed land located in Eastern China, where land reclamation has been undergoing for centuries. A total of 4746 topsoil samples were collected from 2007 to 2010. The SOC density of the reclaimed land (3.18±0.05kgCm(-2); mean±standard error) is significantly lower than that of the adjacent non-reclaimed land (5.71±0.04kgCm(-2)) (pcarbon sequestration potential of the reclaimed lands may achieve a maximum of 5.80±1.81kgCO2m(-2) (mean±SD) when dryland is converted to flooded land with vegetable-rice cropping system and soil pH of ~5.9. Note that in some scenarios the methane emission substantially offsets the carbon sequestration potential, especially for continuous rice cropping system. With the optimal setting for carbon sequestration, it is estimated that the dryland reclaimed in the last 50years in China is able to sequester 0.12milliontons CO2 equivalent per year. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Aggregate and soil organic carbon dynamics in South Chilean Andisols

    Directory of Open Access Journals (Sweden)

    D. Huygens

    2005-01-01

    Full Text Available Extreme sensitivity of soil organic carbon (SOC to climate and land use change warrants further research in different terrestrial ecosystems. The aim of this study was to investigate the link between aggregate and SOC dynamics in a chronosequence of three different land uses of a south Chilean Andisol: a second growth Nothofagus obliqua forest (SGFOR, a grassland (GRASS and a Pinus radiata plantation (PINUS. Total carbon content of the 0-10cm soil layer was higher for GRASS (6.7 kg C m-2 than for PINUS (4.3 kg C m-2, while TC content of SGFOR (5.8 kg C m-2 was not significantly different from either one. High extractable oxalate and pyrophosphate Al concentrations (varying from 20.3-24.4 g kg-1, and 3.9-11.1 g kg-1, respectively were found in all sites. In this study, SOC and aggregate dynamics were studied using size and density fractionation experiments of the SOC, δ13C and total carbon analysis of the different SOC fractions, and C mineralization experiments. The results showed that electrostatic sorption between and among amorphous Al components and clay minerals is mainly responsible for the formation of metal-humus-clay complexes and the stabilization of soil aggregates. The process of ligand exchange between SOC and Al would be of minor importance resulting in the absence of aggregate hierarchy in this soil type. Whole soil C mineralization rate constants were highest for SGFOR and PINUS, followed by GRASS (respectively 0.495, 0.266 and 0.196 g CO2-Cm-2d-1 for the top soil layer. In contrast, incubation experiments of isolated macro organic matter fractions gave opposite results, showing that the recalcitrance of the SOC decreased in another order: PINUS>SGFOR>GRASS. We deduced that electrostatic sorption processes and physical protection of SOC in soil aggregates were the main processes determining SOC stabilization. As a result, high aggregate carbon concentrations, varying from 148 till 48 g kg-1, were encountered for all land use

  2. Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems.

    Science.gov (United States)

    Sowers, Tyler D; Adhikari, Dinesh; Wang, Jian; Yang, Yu; Sparks, Donald L

    2018-05-25

    Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high coassociation with OC in soils containing high Fe content, increase OC sorption extent to poorly crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation. We performed STXM-NEXAFS analysis on 2-line ferrihydrite reacted with leaf litter-extractable dissolved OC and citric acid in the absence and presence of Ca. Organic carbon was found to highly associate with Ca ( R 2 = 0.91). Carboxylic acid moieties were dominantly sequestered; however, Ca facilitated the additional sequestration of aromatic and phenolic moieties. Also, C NEXAFS revealed polyvalent metal ion complexation. Our results provide evidence for the presence of Fe-Ca-OC ternary complexation, which has the potential to significantly impact how organo-mineral associations are modeled.

  3. Total organic carbon in aggregates as a soil recovery indicator

    Science.gov (United States)

    Luciene Maltoni, Katia; Rodrigues Cassiolato, Ana Maria; Amorim Faria, Glaucia; Dubbin, William

    2015-04-01

    The soil aggregation promotes physical protection of organic matter, preservation of which is crucial to improve soil structure, fertility and ensure the agro-ecosystems sustainability. The no-tillage cultivation system has been considered as one of the strategies to increase total soil organic carbono (TOC) contents and soil aggregation, both are closely related and influenced by soil management systems. The aim of this study was to evaluate the distribution of soil aggregates and the total organic carbon inside aggregates, with regard to soil recovery, under 3 different soil management systems, i.e. 10 and 20 years of no-tillage cultivation as compared with soil under natural vegetation (Cerrado). Undisturbed soils (0-5; 5-10; and 10-20 cm depth) were collected from Brazil, Central Region. The soils, Oxisols from Cerrado, were collected from a field under Natural Vegetation-Cerrado (NV), and from fields that were under conventional tillage since 1970s, and 10 and 20 years ago were changed to no-tillage cultivation system (NT-10; NT-20 respectively). The undisturbed samples were sieved (4mm) and the aggregates retained were further fractionated by wet sieving through five sieves (2000, 1000, 500, 250, and 50 μm) with the aggregates distribution expressed as percentage retained by each sieve. The TOC was determined, for each aggregate size, by combustion (Thermo-Finnigan). A predominance of aggregates >2000 μm was observed under NV treatment (92, 91, 82 %), NT-10 (64, 73, 61 %), and NT-20 (71, 79, 63 %) for all three depths (0-5; 5-10; 10-20 cm). In addition greater quantities of aggregates in sizes 1000, 500, 250 and 50 μm under NT-10 and NT-20 treatments, explain the lower aggregate stability under these treatments compared to the soil under NV. The organic C concentration for NV in aggregates >2000 μm was 24,4; 14,2; 8,7 mg/g for each depth (0-5; 5-10; 10-20 cm, respectively), higher than in aggregates sized 250-50 μm (7,2; 5,5; 4,4 mg/g) for all depths

  4. Glassy carbon electrode modified with horse radish peroxidase/organic nucleophilic-functionalized carbon nanotube composite for enhanced electrocatalytic oxidation and efficient voltammetric sensing of levodopa

    Energy Technology Data Exchange (ETDEWEB)

    Shoja, Yalda; Rafati, Amir Abbas, E-mail: aa_rafati@basu.ac.ir; Ghodsi, Javad

    2016-01-01

    A novel and selective enzymatic biosensor was designed and constructed for voltammetric determination of levodopa (L-Dopa) in aqueous media (phosphate buffer solution, pH = 7). Biosensor development was on the basis of to physically immobilizing of horse radish peroxidase (HRP) as electrochemical catalyst by sol–gel on glassy carbon electrode modified with organic nucleophilic carbon nanotube composite which in this composite p-phenylenediamine (pPDA) as organic nucleophile chemically bonded with functionalized MWCNT (MWCNT-COOH). The results of this study suggest that prepared bioorganic nucleophilic carbon nanotube composite (HRP/MWCNT-pPDA) shows fast electron transfer rate for electro oxidation of L-Dopa because of its high electrochemical catalytic activity toward the oxidation of L-Dopa, more −NH{sub 2} reactive sites and large effective surface area. Also in this work we measured L-Dopa in the presence of folic acid and uric acid as interferences. The proposed biosensor was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), FT-IR spectroscopy and cyclic voltammetry (CV). The differential pulse voltammetry (DPV) was used for determination of L-Dopa from 0.1 μM to 1.9 μM with a low detection limit of 40 nM (for S/N = 3) and sensitivity was about 35.5 μA/μM. Also this biosensor has several advantages such as rapid response, high stability and reproducibility. - Highlights: • Glassy carbon electrode modified by a novel composite in which pPDA as nucleophile is chemically attached to MWCNTs. • The developed biosensor exhibited excellent electrocatalytic activity in electrochemically determination of L-Dopa. • The biosensor showed acceptable sensitivity, reproducibility, detection limit, selectivity and stability. • MWCNT-pPDA provides a good electrical conductivity and large effective surface area for enzyme immobilization.

  5. Covalent organic polymer functionalization of activated carbon surfaces through acyl chloride for environmental clean-up

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    2017-01-01

    Nanoporous networks of covalent organic polymers (COPs) are successfully grafted on the surfaces of activated carbons, through a series of surface modification techniques, including acyl chloride formation by thionyl chloride. Hybrid composites of activated carbon functionalized with COPs exhibit...

  6. Impact of shade and cocoa plant densities on soil organic carbon ...

    African Journals Online (AJOL)

    user

    There were no soil organic carbon sequestration in the highest cocoa plant ... It is concluded that cocoa farming could be an effective means to mitigate carbon dioxide ... growth and yield of cocoa at the CRIG substation Bunso (060 13' N,.

  7. Biofilms' contribution to organic carbon in salt marsh sediments

    Science.gov (United States)

    Valentine, K.; Quirk, T. E.; Mariotti, G.; Hotard, A.

    2017-12-01

    Coastal salt marshes are productive environments with high potential for carbon (C) accumulation. Organic C in salt marsh sediment is typically attributed to plant biomass. Recent field measurements, however, suggest that biofilms - mainly composed of benthic diatoms and their secretion - also contribute to basal C in these environments and can be important contributors to marsh productivity, C cycling, and potentially, C sequestration. The potential for biofilms to soil organic C and the influence of mineral sedimentation of biofilm-based C accumulation is unknown. We conducted controlled laboratory experiments to test (1) whether biofilms add measurable amounts of organic C to the sediment and (2) the effect of mineral sedimentation rate on the amount of biofilm-based C accumulation. Settled beds of pure bentonite mud were created in 10-cm-wide cylinders. Each cylinder was inoculated with biofilms collected from a marsh in Louisiana. A small amount of mud was added weekly for 11 weeks. Control experiments without biofilms were also performed. Biofilms were grown with a 12/12 hours cycle, with a gentle mixing of the water column that did not cause sediment resuspension, with a nutrient-rich medium that was exchanged weekly, and in the absence of metazoan grazing. At the end of the experiment, the sediment columns were analyzed for depth-integrated chl-a, loss on ignition (LOI), and total organic carbon (TOC). Chl-a values ranged from 26-113 mg/cm2, LOI values ranged from 86-456 g/m2/yr, and TOC values ranged from 31-211 g/m2/yr. All three of these metrics (chl-a, LOI, and TOC) increased with the rate of mineral sedimentation. These results show that biofilms, in the absence of erosion and grazing, can significantly contribute to C accumulation in salt marshes, especially with high rates of mineral sedimentation. Given the short time scale of the experiment, the increase in organic C accumulation with the rate of sedimentation is attributed to stimulated biofilm

  8. Exploring Soil Organic Carbon Deposits in a Bavarian Catchment

    Science.gov (United States)

    Kriegs, Stefanie; Hobley, Eleanor; Schwindt, Daniel; Völkel, Jörg; Kögel-Knabner, Ingrid

    2017-04-01

    The distribution of soil organic carbon (SOC) in the landscape is not homogeneous, but shows high variability from the molecular to the landscape scale. The aims of our work are 1.) to detect hot spots of SOC storage within different positions in a landscape; 2.) to outline differences (or similarities) between SOC characteristics of erosional and accumulative landscape positions; and 3.) to determine whether localised SOC deposits are dominated by fresh and labile organic matter (OM) or old and presumably stable OM. These findings are crucial for the evaluation of the landscapés vulnerability towards SOC losses caused by management or natural disturbances such as erosional rainfall events. Sampling sites of our study are located in a catchment at the foothills of the Bavarian Forest in south-east Germany. Within this area three landform positions were chosen for sampling: a) a slope with both erosional depletion and old colluvial deposits, b) a foothill with recent colluvial deposits and c) a floodplain with alluvial deposits. In order to consider both heterogeneity within a single landform position and between landforms several soil profiles were sampled at every position. Samples were taken to a maximal depth of 150 cm, depending on the presence of rocks or ground-water level, and analysed for bulk density, total carbon (TOC), inorganic carbon (IC) and texture. SOC densities and stocks were calculated. A two-step physical density fractionation using Sodium-Polytungstate (1.8 g/cm3 and 2.4 g/cm3) was applied to determine the contribution of the different soil organic matter fractions to the detected SOC deposits. Literature assumes deep buried SOC to be particularly old and stable, so we applied Accelerator Mass Spectrometry Radiocarbon Dating (AMS 14C) to bulk soil samples in order to verify this hypothesis. The results show that the floodplain soils contain higher amounts of SOC compared with slopes and foothills. Heterogeneity within the sites was smaller

  9. Susceptibility of Permafrost Soil Organic Carbon under Warming Climate

    Science.gov (United States)

    Yang, Z.; Wullschleger, S. D.; Liang, L.; Graham, D. E.; Gu, B.

    2015-12-01

    Degradation of soil organic carbon (SOC) that has been stored in permafrost is a key concern under warming climate because it could provide a positive feedback. Studies and conceptual models suggest that SOC degradation is largely controlled by the decomposability of SOC, but it is unclear exactly what portions of SOC are susceptible to rapid breakdown and what mechanisms may be involved in SOC degradation. Using a suite of analytical techniques, we examined the dynamic consumption and production of labile SOC compounds, including sugars, alcohols, and small molecular weight organic acids in incubation experiments (up to 240 days at either -2 or 8 °C) with a tundra soil under anoxic conditions, where SOC respiration and iron(III) reduction were monitored. We observe that sugars and alcohols are main components in SOC accounting for initial rapid release of CO2 and CH4 through anaerobic fermentation, whereas the fermentation products such as acetate and formate are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important roles as an electron acceptor in tundra SOC respiration. These observations corroborate strongly with the glucose addition during incubation, in which rapid CO2 and CH4 production is observed concurrently with rapid production and consumption of organics such as acetate. Thus, the biogeochemical processes we document here are pertinent to understanding the accelerated SOC decomposition with temperature and could provide basis for model predicting feedbacks to climate warming in the Arctic.

  10. Single-walled carbon nanotubes nanocomposite microacoustic organic vapor sensors

    Energy Technology Data Exchange (ETDEWEB)

    Penza, M. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy)]. E-mail: michele.penza@brindisi.enea.it; Tagliente, M.A. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Aversa, P. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Cassano, G. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Capodieci, L. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy)

    2006-07-15

    We have developed highly sensitive microacoustic vapor sensors based on surface acoustic waves (SAWs) configured as oscillators using a two-port resonator 315, 433 and 915 MHz device. A nanocomposite film of single-walled carbon nanotubes (SWCNTs) embedded in a cadmium arachidate (CdA) amphiphilic organic matrix was prepared by Langmuir-Blodgett technique with a different SWCNTs weight filler content onto SAW transducers as nanosensing interface for vapor detection, at room temperature. The structural properties and surface morphology of the nanocomposite have been examined by X-ray diffraction, transmission and scanning electron microscopy, respectively. The sensing properties of SWCNTs nanocomposite LB films consisting of tangled nanotubules have been also investigated by using Quartz Crystal Microbalance 10 MHz AT-cut quartz resonators. The measured acoustic sensing characteristics indicate that the room-temperature SAW sensitivity to polar and nonpolar tested organic molecules (ethanol, ethylacetate, toluene) of the SWCNTs-in-CdA nanocomposite increases with the filler content of SWCNTs incorporated in the nanocomposite; also the SWCNTs-in-CdA nanocomposite vapor sensitivity results significantly enhanced with respect to traditional organic molecular cavities materials with a linearity in the frequency change response for a given nanocomposite weight composition and a very low sub-ppm limit of detection.

  11. Analysis of Seasonal Soil Organic Carbon Content at Bukit Jeriau Forest, Fraser Hill, Pahang

    International Nuclear Information System (INIS)

    Ahmad Adnan Mohamed; Ahmad Adnan Mohamed; Sahibin Abd Rahim; David Allan Aitman; Mohd Khairul Amri Kamarudin; Mohd Khairul Amri Kamarudin

    2016-01-01

    Soil carbon is the carbon held within the soil, primarily in association with its organic content. The total soil organic carbon study was determined in a plot at Bukit Jeriau forest in Bukit Fraser, Pahang, Malaysia. The aim of this study is to determine the changing of soil organic carbon between wet season and dry season. Soil organic carbon was fined out using titrimetric determination. The soil organic carbon content in wet season is 223.24 t/ ha while dry season is 217.90 t/ ha. The soil pH range in wet season is between 4.32 to 4.45 and in dry season in 3.95 to 4.08 which is considered acidic. Correlation analysis showed that soil organic carbon value is influenced by pH value and climate. Correlation analysis between clay and soil organic carbon with depth showed positively significant differences and clay are very much influenced soil organic carbon content. Correlation analysis between electrical conductivity and soil organic carbon content showed negative significantly difference on wet season and positively significant different in dry season. (author)

  12. Dynamics of dissolved organic carbon in a stream during a quarter century of forest succession

    Science.gov (United States)

    Judy L. Meyer; Jackson Webster; Jennifer Knoepp; E.F. Benfield

    2014-01-01

    Dissolved organic carbon (DOC) is a heterogeneous mixture of compounds that makes up a large fraction of the organic matter transported in streams. It plays a significant role in many ecosystems. Riverine DOC links organic carbon cycles of continental and oceanic ecosystems. It is a significant trophic resource in stream food webs. DOC imparts color to lakes,...

  13. Sorption of Heterocyclic Organic Compounds to Multiwalled Carbon Nanotubes.

    Science.gov (United States)

    Metzelder, Florian; Funck, Matin; Schmidt, Torsten C

    2018-01-16

    Sorption is an important natural and technical process. Sorption coefficients are typically determined in batch experiments, but this may be challenging for weakly sorbing compounds. An alternative method enabling analysis of those compounds is column chromatography. A column packed with the sorbent is used and sorption data are determined by relating sorbate retention to that of a nonretarded tracer. In this study, column chromatography was applied for the first time to study sorption of previously hardly investigated heterocyclic organic compounds to multiwalled carbon nanotubes (MWCNTs). Sorption data for these compounds are very limited in literature, and weak sorption is expected from predictions. Deuterium oxide was used as nonretarded tracer. Sorption isotherms were well described by the Freundlich model and data showed reasonable agreement with predicted values. Sorption was exothermic and physisorption was observed. H-bonding may contribute to overall sorption, which is supported by reduced sorption with increasing ionic strength due to blocking of functional groups. Lowering pH reduced sorption of ionizable compounds, due to electrostatic repulsion at pH 3 where sorbent as well as sorbates were positively charged. Overall, column chromatography was successfully used to study sorption of heterocyclic compounds to MWCNTs and could be applied for other carbon-based sorbents.

  14. Organic Carbon Burial in Brazilian Mangrove Sediments (Invited)

    Science.gov (United States)

    Sanders, C.; Smoak, J. M.; Sanders, L.; Patchineelam, S.

    2010-12-01

    This study reviews the organic carbon (OC) burial rates in mangrove forests, margins and mud flats in geographically distinct areas of the Brazilian coastline. We exam the burial rates, taking into account the geomorphology of each region. Our initial results indicate that the Northeastern region of Brazil is sequestering significantly more OC than in the Southeastern areas, being that the mass sediment accumulation rates remained consistent within the forests as opposed to large variations found in the mudflats. The other pertinent factor was OC content, which differed substantially in respect to region. Given that the mangrove forests of the Southeastern regions of Brazil may be more susceptible to a rising sea level, as these areas are constricted by vast mountain ranges, this work attempts to put in perspective the possible impacts of climate change on mangrove ecosystems and OC burial along the Brazilian coastal ocean. We also compare our result to global averages.

  15. Soil Organic Carbon dynamics in agricultural soils of Veneto Region

    Science.gov (United States)

    Bampa, F. B.; Morari, F. M.; Hiederer, R. H.; Toth, G. T.; Giandon, P. G.; Vinci, I. V.; Montanarella, L. M.; Nocita, M.

    2012-04-01

    One of the eight soil threats expressed in the European Commission's Thematic Strategy for Soil Protection (COM (2006)231 final) it's the decline in Soil Organic Matter (SOM). His preservation is recognized as with the objective to ensure that the soils of Europe remain healthy and capable of supporting human activities and ecosystems. One of the key goals of the strategy is to maintain and improve Soil Organic Carbon (SOC) levels. As climate change is identified as a common element in many of the soil threats, the European Commission (EC) intends to assess the actual contribution of the soil protection to climate change mitigation and the effects of climate change on the possible depletion of SOM. A substantial proportion of European land is occupied by agriculture, and consequently plays a crucial role in maintaining natural resources. Organic carbon preservation and sequestration in the EU's agricultural soils could have some potential to mitigate the effects of climate change, particularly linked to preventing certain land use changes and maintaining SOC stocks. The objective of this study is to assess the SOC dynamics in agricultural soils (cropland and grassland) at regional scale, focusing on changes due to land use. A sub-objective would be the evaluation of the most used land management practices and their effect on SOC content. This assessment aims to determine the geographical distribution of the potential GHG mitigation options, focusing on hot spots in the EU, where mitigation actions would be particularly efficient and is linked with the on-going work in the JRC SOIL Action. The pilot area is Veneto Region. The data available are coming from different sources, timing and involve different variables as: soil texture, climate, soil disturbance, managements and nutrients. The first source of data is the LUCAS project (Land Use/Land Cover Area Frame statistical Survey). Started in 2001, the LUCAS project aims to monitor changes in land cover/use and

  16. Physical and chemical protection of soil organic carbon in three agricultural soils with different contents of calcium carbonate

    International Nuclear Information System (INIS)

    Clough, A.; Skjemstad, J.O.

    2000-01-01

    The amount of organic carbon physically protected by entrapment within aggregates and through polyvalent cation organic matter bridging was determined on non-calcareous and calcareous soils. The composition of organic carbon in whole soils and 13 C NMR analysis. High energy photo-oxidation was carried out on <53 μm fractions and results from the NMR spectra showed 17-40% of organic carbon was in a condensed aromatic form, most likely charcoal (char). The concept that organic material remaining after photo-oxidation may be physically protected within aggregates was investigated by treating soils with a mild acid prior to photo-oxidation. More organic material was protected in the calcareous than the non-calcareous soils, regardless of whether the calcium occurred naturally or was an amendment. Acid treatment indicated that the presence of exchangeable calcium reduced losses of organic material upon photo-oxidation by about 7% due to calcium bridging. These results have implications for N fertiliser recommendations based upon organic carbon content. Firstly, calcium does not impact upon degradability of organic material to an extent likely to affect N fertiliser recommendations. Secondly, standard assessment techniques overestimate active organic carbon content in soils with high char content. Copyright (2000) CSIRO Publishing

  17. Electric double layer capacitance on hierarchical porous carbons in an organic electrolyte

    OpenAIRE

    Yamada, Hirotoshi; Moriguchi, Isamu; Kudo, Tetsuichi

    2008-01-01

    Nanoporous carbons were prepared by using colloidal crystal as a template. Nitrogen adsorption/desorption isotherms and transmission electron microscope images revealed that the porous carbons exhibit hierarchical porous structures with meso/macropores and micropores. Electric double layer capacitor performance of the porous carbons was investigated in an organic electrolyte of 1 M LiClO4 in propylene carbonate and dimethoxy ethane. The hierarchical porous carbons exhibited large specific dou...

  18. Improved automation of dissolved organic carbon sampling for organic-rich surface waters.

    Science.gov (United States)

    Grayson, Richard P; Holden, Joseph

    2016-02-01

    In-situ UV-Vis spectrophotometers offer the potential for improved estimates of dissolved organic carbon (DOC) fluxes for organic-rich systems such as peatlands because they are able to sample and log DOC proxies automatically through time at low cost. In turn, this could enable improved total carbon budget estimates for peatlands. The ability of such instruments to accurately measure DOC depends on a number of factors, not least of which is how absorbance measurements relate to DOC and the environmental conditions. Here we test the ability of a S::can Spectro::lyser™ for measuring DOC in peatland streams with routinely high DOC concentrations. Through analysis of the spectral response data collected by the instrument we have been able to accurately measure DOC up to 66 mg L(-1), which is more than double the original upper calibration limit for this particular instrument. A linear regression modelling approach resulted in an accuracy >95%. The greatest accuracy was achieved when absorbance values for several different wavelengths were used at the same time in the model. However, an accuracy >90% was achieved using absorbance values for a single wavelength to predict DOC concentration. Our calculations indicated that, for organic-rich systems, in-situ measurement with a scanning spectrophotometer can improve fluvial DOC flux estimates by 6 to 8% compared with traditional sampling methods. Thus, our techniques pave the way for improved long-term carbon budget calculations from organic-rich systems such as peatlands. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Simulating the effects of light intensity and carbonate system composition on particulate organic and inorganic carbon production in Emiliania huxleyi.

    Science.gov (United States)

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2015-05-07

    Coccolithophores play an important role in the marine carbon cycle. Variations in light intensity and external carbonate system composition alter intracellular carbon fluxes and therewith the production rates of particulate organic and inorganic carbon. Aiming to find a mechanistic explanation for the interrelation between dissolved inorganic carbon fluxes and particulate carbon production rates, we develop a numerical cell model for Emiliania huxleyi, one of the most abundant coccolithophore species. The model consists of four cellular compartments, for each of which the carbonate system is resolved dynamically. The compartments are connected to each other and to the external medium via substrate fluxes across the compartment-confining membranes. By means of the model we are able to explain several pattern observed in particulate organic and inorganic carbon production rates for different strains and under different acclimation conditions. Particulate organic and inorganic carbon production rates for instance decrease at very low external CO2 concentrations. Our model suggests that this effect is caused mainly by reduced HCO3(-) uptake rates, not by CO2 limitation. The often observed decrease in particulate inorganic carbon production rates under Ocean Acidification is explained by a downregulation of cellular HCO3(-) uptake. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Bacterial formation of phosphatic laminites off Peru.

    Science.gov (United States)

    Arning, E T; Birgel, D; Brunner, B; Peckmann, J

    2009-06-01

    Authigenic phosphatic laminites enclosed in phosphorite crusts from the shelf off Peru (10 degrees 01' S and 10 degrees 24' S) consist of carbonate fluorapatite layers, which contain abundant sulfide minerals including pyrite (FeS(2)) and sphalerite (ZnS). Low delta(34)S(pyrite) values (average -28.8 per thousand) agree with bacterial sulfate reduction and subsequent pyrite formation. Stable sulfur isotopic compositions of sulfate bound in carbonate fluorapatite are lower than that of sulfate from ambient sea water, suggesting bacterial reoxidation of sulfide by sulfide-oxidizing bacteria. The release of phosphorus and subsequent formation of the autochthonous phosphatic laminites are apparently caused by the activity of sulfate-reducing bacteria and associated sulfide-oxidizing bacteria. Following an extraction-phosphorite dissolution-extraction procedure, molecular fossils of sulfate-reducing bacteria (mono-O-alkyl glycerol ethers, di-O-alkyl glycerol ethers, as well as the short-chain branched fatty acids i/ai-C(15:0), i/ai-C(17:0) and 10MeC(16:0)) are found to be among the most abundant compounds. The fact that these molecular fossils of sulfate-reducing bacteria are distinctly more abundant after dissolution of the phosphatic laminite reveals that the lipids are tightly bound to the mineral lattice of carbonate fluorapatite. Moreover, compared with the autochthonous laminite, molecular fossils of sulfate-reducing bacteria are: (1) significantly less abundant and (2) not as tightly bound to the mineral lattice in the other, allochthonous facies of the Peruvian crusts consisting of phosphatic coated grains. These observations confirm the importance of sulfate-reducing bacteria in the formation of the phosphatic laminite. Model calculations highlight that organic matter degradation by sulfate-reducing bacteria has the potential to liberate sufficient phosphorus for phosphogenesis.

  1. Organic carbon balance and net ecosystem metabolism in Chesapeake Bay

    Science.gov (United States)

    Kemp, W.M.; Smith, E.M.; Marvin-DiPasquale, M.; Boynton, W.R.

    1997-01-01

    The major fluxes of organic carbon associated with physical transport and biological metabolism were compiled, analyzed and compared for the mainstem portion of Chesapeake Bay (USA). In addition, 5 independent methods were used to calculate the annual mean net ecosystem metabolism (NEM = production - respiration) for the integrated Bay. These methods, which employed biogeochemical models, nutrient mass-balances anti summation of individual organic carbon fluxes, yielded remarkably similar estimates, with a mean NEM of +50 g C m-2 yr-1 (?? SE = 751, which is approximately 8% of the estimated annual average gross primary production. These calculations suggest a strong cross-sectional pattern in NEM throughout the Bay, wherein net heterotrophic metabolism prevails in the pelagic zones of the main channel, while net autotrophy occurs in the littoral zones which flank the deeper central area. For computational purposes, the estuary was separated into 3 regions along the land-sea gradient: (1) the oligohaline Upper Bay (11% of total area); (2) the mesohaline Mid Bay (36% of area); and (3) the polyhaline Lower Bay (53% of area). A distinct regional trend in NEM was observed along this salinity gradient, with net here(atrophy (NEM = 87 g C m-2 yr-1) in the Upper Bay, balanced metabolism in the Mid Bay and net autotrophy (NEM = +92 g C m-2 yr-1) in the Lower Bay. As a consequence of overall net autotrophy, the ratio of dissolved inorganic nitrogen (DIN) to total organic nitrogen (TON) changed from DIN:TON = 5.1 for riverine inputs to DIN:TON = 0.04 for water exported to the ocean. A striking feature of this organic C mass-balance was the relative dominance of biologically mediated metabolic fluxes compared to physical transport fluxes. The overall ratio of physical TOC inputs (1) to biotic primary production (P) was 0.08 for the whole estuary, but varied dramatically from 2.3 in the Upper Bay to 0.03 in the Mid and Lower Bay regions. Similarly, ecosystem respiration was

  2. Monitoring of organic and elemental carbon (OC/EC) in the atmospheric aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Hannemann, A.; Fuchs, J.; Jaeschke, W.; Weingartner, E.; Baltensperger, U.

    2003-03-01

    A new instrument for the measurement of ambient carbonaceous aerosol concentrations is described, which enables discrimination between organic and elemental carbon on a semi-continuous basis. (author)

  3. Organic carbon, nitrogen and phosphorus contents of some soils of kaliti tea-estate, Bangladesh

    International Nuclear Information System (INIS)

    Ahmed, M. S.; Shahin, M. M. H.; Sanaullah, A. F. M.

    2005-01-01

    Some soil samples were collected from Kaliti Tea-Estate of Moulvibazar district, Bangladesh. Total nitrogen, organic carbon, organic matter, carbon-nitrogen ratio and available phosphorus content of the collected soil samples of different depths and of different topographic positions have been determined. Total nitrogen was found 0.07 to 0.12 % organic carbon and organic matter content found to vary from 0.79 to 1.25 and 1.36 to 2.15 % respectively. Carbon-nitrogen ratio of these soils varied from 9.84 to 10.69, while available phosphorus content varied from 2.11 to 4.13 ppm. (author)

  4. Dynamics of Intracellular Polymers in Enhanced Biological Phosphorus Removal Processes under Different Organic Carbon Concentrations

    Directory of Open Access Journals (Sweden)

    Lizhen Xing

    2013-01-01

    Full Text Available Enhanced biological phosphorus removal (EBPR may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the applied low organic carbon concentrations were advantageous for the enrichment of PAOs. A low influent organic carbon concentration induced a high production of extracellular carbohydrate. During both anaerobic and aerobic endogenous respirations, when glycogen decreased to around 80 ± 10 mg C per gram of volatile suspended solids, PAOs began to utilize polyphosphate significantly. Regressed by the first-order reaction model, glycogen possessed the highest degradation rate and then was followed by polyphosphate, while biomass decay had the lowest degradation rate.

  5. Modeling Soil Organic Carbon Turnover in Four Temperate Forests Based on Radiocarbon Measurements of Heterotrophic Respiration and Soil Organic Carbon

    Science.gov (United States)

    Ahrens, B.; Borken, W.; Muhr, J.; Schrumpf, M.; Savage, K. E.; Wutzler, T.; Trumbore, S.; Reichstein, M.

    2011-12-01

    Soils of temperate forests store significant amounts of soil organic matter and are considered to be net sinks of atmospheric CO2. Soil organic carbon (SOC) dynamics have been studied using the Δ14C signature of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ14C signature of CO2 evolved during the incubation of soil and roots has been widely used together with Δ14C of total soil respiration to partition soil respiration into heterotrophic respiration (Rh) and root respiration. However, these data have rarely been used together as observational constraints to determine SOC turnover times. Here, we present a multiple constraints approach, where we used SOC stock and its Δ14C signature, and heterotrophic respiration and its Δ14C signature to estimate SOC turnover times of a simple serial two-pool model via Bayesian optimization. We used data from four temperate forest ecosystems in Germany and the USA with different disturbance and management histories from selective logging to afforestation in the late 19th and early 20th century. The Δ14C signature of the atmosphere with its prominent bomb peak was used as a proxy for the Δ14C signature of aboveground and belowground litterfall. The Δ14C signature of litterfall was lagged behind the atmospheric signal to account for the period between photosynthetic fixation of carbon and its addition to SOC pools. We showed that the combined use of Δ14C measurements of Rh and SOC stocks helped to better constrain turnover times of the fast pool (primarily by Δ14C of Rh) and the slow pool (primarily by Δ14C of SOC). In particular, by introducing two additional parameters that describe the deviation from steady state of the fast and slow cycling pool for both SOC and SO14C, we were able to demonstrate that we cannot maintain the often used steady-state assumption of SOC models in general. Furthermore, a new transport version of our model, including SOC transport via

  6. Infrared Organic Light-Emitting Diodes with Carbon Nanotube Emitters.

    Science.gov (United States)

    Graf, Arko; Murawski, Caroline; Zakharko, Yuriy; Zaumseil, Jana; Gather, Malte C

    2018-03-01

    While organic light-emitting diodes (OLEDs) covering all colors of the visible spectrum are widespread, suitable organic emitter materials in the near-infrared (nIR) beyond 800 nm are still lacking. Here, the first OLED based on single-walled carbon nanotubes (SWCNTs) as the emitter is demonstrated. By using a multilayer stacked architecture with matching charge blocking and charge-transport layers, narrow-band electroluminescence at wavelengths between 1000 and 1200 nm is achieved, with spectral features characteristic of excitonic and trionic emission of the employed (6,5) SWCNTs. Here, the OLED performance is investigated in detail and it is found that local conduction hot-spots lead to pronounced trion emission. Analysis of the emissive dipole orientation shows a strong horizontal alignment of the SWCNTs with an average inclination angle of 12.9° with respect to the plane, leading to an exceptionally high outcoupling efficiency of 49%. The SWCNT-based OLEDs represent a highly attractive platform for emission across the entire nIR. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. 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)

  8. Combined application of bio-organic phosphate and phosphorus solubilizing bacteria (Bacillus strain MWT 14) improve the performance of bread wheat with low fertilizer input under an arid climate.

    Science.gov (United States)

    Tahir, Muhammad; Khalid, Umaira; Ijaz, Muhammad; Shah, Ghulam Mustafa; Naeem, Muhammad Asif; Shahid, Muhammad; Mahmood, Khalid; Ahmad, Naveed; Kareem, Fazal

    2018-04-24

    This study was aimed to investigate the effect of bio-organic phosphate either alone or in combination with phosphorus solubilizing bacteria strain (Bacillus MWT-14) on the growth and productivity of two wheat cultivars (Galaxy-2013 and Punjab-2011) along with recommended (150-100NPkgha -1 ) and half dose (75-50NPkgha -1 ) of fertilizers. The combined application of bio-organic phosphate and the phosphorous solubilizing bacteria strain at either fertilizer level significantly improved the growth, yield parameters and productivity of both wheat cultivars compared to non-inoculated control treatments. The cultivar Punjab-2011 produced the higher chlorophyll contents, crop growth rate, and the straw yield at half dose of NP fertilizer; while Galaxy-2013, with the combined application of bio-organic phosphate and phosphorous solubilizing bacteria under recommended NP fertilizer dose. Combined over both NP fertilizer levels, the combined use of bio-organic phosphate and phosphorous solubilizing bacteria enhanced the grain yield of cultivar Galaxy-2013 by 54.3% and that of cultivar Punjab-2011 by 83.3%. The combined application of bio-organic phosphate and phosphorous solubilizing bacteria also increased the population of phosphorous solubilizing bacteria, the soil organic matter and phosphorous contents in the soil. In conclusion, the combined application of bio-organic phosphate and phosphorous solubilizing bacteria offers an eco-friendly option to harvest the better wheat yield with low fertilizer input under arid climate. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  9. Accounting for Organic Carbon Change in Deep Soil Altered Carbon Sequestration Efficiency

    Science.gov (United States)

    Li, J.; Liang, F.; Xu, M.; Huang, S.

    2017-12-01

    Study on soil organic carbon (SOC) sequestration under fertilization practices in croplands lacks information of soil C change at depth lower than plow layer (i.e. 20 30-cm). By synthesizing long-term datasets of fertilization experiments in four typical Chinese croplands representing black soil at Gongzhuling(GZL), aquatic Chao soil at Zhengzhou(ZZ), red soil at Qiyang(QY) and purple soil at Chongqing(CQ) city, we calculated changes in SOC storage relative to initial condition (ΔSOC) in 0-20cm and 0-60cm, organic C inputs (OC) from the stubble, roots and manure amendment, and C sequestration efficiency (CSE: the ratio of ΔSOC over OC) in 0-20cm and 0-60cm. The fertilization treatments include cropping with no fertilization (CK), chemical nitrogen, phosphorus and potassium fertilizers (NPK) and combined chemical fertilizers and manure (NPKM). Results showed SOC storage generally decreased with soil depth (i.e. 0-20 > 20-40, 40-60 cm) and increased with fertilizations (i.e. initial fertilizations, soil at depth (>20cm) can act as important soil carbon sinks in intrinsically high fertility soils (i.e. black soil) but less likely at poor fertility soil (i.e. aquatic Chao soil). It thus informs the need to account for C change in deep soils for estimating soil C sequestration capacity particularly with indigenously fertile cropland soils.

  10. [Distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta].

    Science.gov (United States)

    Dong, Hong-Fang; Yu, Jun-Bao; Guan, Bo

    2013-01-01

    Applying the method of physical fractionation, distribution characteristics of soil organic carbon and its composition in Suaeda salsa wetland in the Yellow River delta were studied. The results showed that the heavy fraction organic carbon was the dominant component of soil organic carbon in the studied region. There was a significantly positive relationship between the content of heavy fraction organic carbon, particulate organic carbon and total soil organic carbon. The ranges of soil light fraction organic carbon ratio and content were 0.008% - 0.15% and 0.10-0.40 g x kg(-1), respectively, and the range of particulate organic carbon ratio was 8.83% - 30.58%, indicating that the non-protection component of soil organic carbon was low and the carbon pool was relatively stable in Suaeda salsa wetland of the Yellow River delta.

  11. Influence of sludge retention time on tolerance of copper toxicity for polyphosphate accumulating organisms linked to polyhydroxyalkanoates metabolism and phosphate removal.

    Science.gov (United States)

    Tsai, Yung-Pin; Chen, Hsiu-Ting

    2011-12-01

    This study explored the influence of sludge retention time (SRT) on tolerance of copper invasion for polyphosphate accumulating organisms (PAOs) in an enhanced biological phosphorus removal (EBPR). The experimental data showed the anaerobic polyhydroxyalkanoates (PHA) storage for the sludge at 10d SRT was less influenced by copper invasion than those at 5d and 15d SRTs. The reaction of PAOs aerobically taking up phosphate for the sludge at 5d or 15d SRT almost ceased at 2 mg Cu L(-1), whereas PAOs in the sludge at 10d SRT retained half of the ability to take up phosphate. Both the PHAs degradation and synthesis rates decreased with increasing copper concentration, regardless of the SRTs. However, the copper inhibition of the former was greater than that of the later. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Depositional environments inferred from variations of calcium carbonate, organic carbon, and sulfide sulfur: a core from southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A.L.; Iyer, S.D.; Chauhan, O.S.; PrakashBabu, C.

    Pleistocene has been inferred. The higher contents of organic carbon and sulfide sulfur and their negative relationship clearly establish the existence of a reducing environment below 65 cm subbottom depth. The occurrence of pyrite framboids and crystals...

  13. Assessment of the potential impact of the phosphate industry along the Syrian Coast by evaluating 210Po and 210Pb levels in sediment, seawater and selected marine organisms

    International Nuclear Information System (INIS)

    Al-Masri, S.; Mamish, S.

    2000-12-01

    Phosphate industry is considered to be one of the potential sources of natural radionuclides in Syrian environment. Most of the phosphate ore is exported in large quantities via one of the main Syrian ports (Tartous) situated on the east coast of the Mediterranean Sea (34 54 North , 35 52 East). The impact of the loading cargoes on the marine environment has been evaluated. 210 Po and 210 Pb in seawater, sediment and marine organisms have been determined. Results have shown a significant enhancement of these two radionuclides in sediment and surface water inside the port area. The highest 210 Po and 210 Pb concentrations observed in sediment were found to be 170 Bq.kg -1 and 64 Bq.kg -1 respectively. While, 210 Pb and 210 Po concentrations in surface water ranged from 5 to 20 m Bq.l -1 and 0.93 to 3.23 m Bq.l -1 . In addition, other naturally occurring radionuclides were also determined in the collected sediment samples and relatively higher values ( 226 Ra = 33.2 Bq.kg -1 and 234 Th = 88 Bq.kg -1 ) were observed for those samples collected from inside the port. However, the effect of loading cargoes on the near marine environment was found to be mainly related to wind direction where air particulate carrying radioactivity either being blown to lands or sea. Moreover, comparable values of 210 Po and 210 Pb for all marine organisms (algae, crab and fish) have been observed and it is not recommended to use these organisms for evaluating the effect of phosphate industry on marine environment. This is due to the fact that marine organisms accumulate 210 Po and 210 Pb in their body. Two core samples were also collected in order to investigate the history of pollution in the port. Results have shown a complex relation for unsupported 210 Pb with depth, where the constant supply dating method can not be applied. This is due to the fact that two sources for unsupported 210 Pb being observed in the port area; viz. radon gas and phosphate dust carrying radioactivity

  14. Examining organic carbon transport by the Orinoco River using SeaWiFS imagery

    Science.gov (United States)

    López, Ramón; Del Castillo, Carlos E.; Miller, Richard L.; Salisbury, Joseph; Wisser, Dominik

    2012-09-01

    The Orinoco River is the fourth largest in the world in terms of water discharge and organic carbon export to the ocean. River export of organic carbon is a key component of the carbon cycle and the global carbon budget. Here, we examined the seasonal transport of organic carbon by the Orinoco River into the eastern Caribbean using the conservative relationship of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in low salinity coastal waters influenced by river plumes. In situ measurements of CDOM absorption, DOC, and salinity were used to develop an empirical model for DOC concentration at the Orinoco River Plume. Satellite remote sensing reflectances were used with empirical models to determine DOC and Particulate organic carbon (POC) river transport. Our estimates of CDOM and DOC significantly correlated with in situ measurements and were within the expected ranges for the river. Total organic carbon transport by the Orinoco River during the period of 1998 to 2010 was 7.10 ×1012 g C y-1, from 5.29 × 1012 g C y-1 of DOC and 1.81 × 1012 g C y-1 of POC, representing ˜6% increase to previous published estimates. The variability in organic carbon transport responded to the seasonality in river flow more than to changes in organic carbon concentration in the river. Our results corroborate that is possible to estimate organic carbon transport using ocean color data at global scales. This is needed to reduce the uncertainties of land-ocean carbon fluxes.

  15. Tracing the sources of organic carbon in freshwater systems

    Science.gov (United States)

    Glendell, Miriam; Meersmans, Jeroen; Barclay, Rachel; Yvon-Durocher, Gabriel; Barker, Sam; Jones, Richard; Hartley, Iain; Dungait, Jennifer; Quine, Timothy

    2016-04-01

    Quantifying the lateral fluxes of carbon from land to inland waters is critical for the understanding of the global carbon cycle and climate change mitigation. However, the crucial role of rivers in receiving, transporting and processing the equivalent of terrestrial net primary production in their watersheds has only recently been recognised. In addition, the fluxes of carbon from land to ocean, and the impact of anthropogenic perturbation, are poorly quantified. Therefore, a mechanistic understanding of the processes involved in the loss and preservation of C along the terrestrial-aquatic continuum is required to predict the present and future contribution of aquatic C fluxes to the global C budget. This pilot study examines the effect of land use on the fate of organic matter within two headwater catchments in Cornwall (UK) in order to develop a methodological framework for investigating C-cycling across the entire terrestrial-aquatic continuum. To this end, we aim to characterise the spatial heterogeneity of soil erosion driven lateral fluxes of SOC to identify areas of erosion and deposition using 137Cs radio-isotope and trace the terrestrial versus aquatic origin of C along the river reaches and in lake sediments at the catchment outlet. The 3D spatial distribution of SOC has been investigated by sampling three depth increments (i.e. 0-15cm, 15-30cm and 30-50cm) along 14 hillslope transects within two sub-catchments of ˜km2 each. In total, 80 terrestrial sites were monitored and analysed for total C and N, and bulk stable 13C/15N isotope values, while 137Cs was used to obtain a detailed understanding of the spatial - temporal variability in erosion driven lateral fluxes of SOC within the catchments. The relative contribution of terrestrial and aquatic C was examined along the river reaches as well as in lake sediments at the catchment outlet by considering n-alkane signatures. By linking the C accumulation rates in lake sediments over decadal timescales from

  16. Redox-controlled carbon and phosphorus burial: A mechanism for enhanced organic carbon sequestration during the PETM

    Science.gov (United States)

    Komar, Nemanja; Zeebe, Richard E.

    2017-12-01

    Geological records reveal a major perturbation in carbon cycling during the Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma), marked by global warming of more than 5 °C and a prominent negative carbon isotope excursion of at least 2.5‰ within the marine realm. The entire event lasted about 200,000 yr and was associated with a massive release of light carbon into the ocean-atmosphere system over several thousands of years. Here we focus on the terminal stage of the PETM, during which the ocean-atmosphere system rapidly recovered from the carbon cycle perturbation. We employ a carbon-cycle box model to examine the feedbacks between surface ocean biological production, carbon, oxygen, phosphorus, and carbonate chemistry during massive CO2 release events, such as the PETM. The model results indicate that the redox-controlled carbon-phosphorus feedback is capable of producing enhanced organic carbon sequestration during large carbon emission events. The locale of carbon oxidation (ocean vs. atmosphere) does not affect the amount of carbon sequestered. However, even though the model produces trends consistent with oxygen, excess accumulation rates of organic carbon (∼1700 Pg C during the recovery stage), export production and δ13 C data, it fails to reproduce the magnitude of change of sediment carbonate content and the CCD over-deepening during the recovery stage. The CCD and sediment carbonate content overshoot during the recovery stage is muted by a predicted increase in CaCO3 rain. Nonetheless, there are indications that the CaCO3 export remained relatively constant during the PETM. If this was indeed true, then an initial pulse of 3,000 Pg C followed by an additional, slow leak of 2,500 Pg C could have triggered an accelerated nutrient supply to the surface ocean instigating enhanced organic carbon export, consequently increasing organic carbon sequestration, resulting in an accelerated restoration of ocean-atmosphere biogeochemistry during the termination

  17. Maximum total organic carbon limit for DWPF melter feed

    International Nuclear Information System (INIS)

    Choi, A.S.

    1995-01-01

    DWPF recently decided to control the potential flammability of melter off-gas by limiting the total carbon content in the melter feed and maintaining adequate conditions for combustion in the melter plenum. With this new strategy, all the LFL analyzers and associated interlocks and alarms were removed from both the primary and backup melter off-gas systems. Subsequently, D. Iverson of DWPF- T ampersand E requested that SRTC determine the maximum allowable total organic carbon (TOC) content in the melter feed which can be implemented as part of the Process Requirements for melter feed preparation (PR-S04). The maximum TOC limit thus determined in this study was about 24,000 ppm on an aqueous slurry basis. At the TOC levels below this, the peak concentration of combustible components in the quenched off-gas will not exceed 60 percent of the LFL during off-gas surges of magnitudes up to three times nominal, provided that the melter plenum temperature and the air purge rate to the BUFC are monitored and controlled above 650 degrees C and 220 lb/hr, respectively. Appropriate interlocks should discontinue the feeding when one or both of these conditions are not met. Both the magnitude and duration of an off-gas surge have a major impact on the maximum TOC limit, since they directly affect the melter plenum temperature and combustion. Although the data obtained during recent DWPF melter startup tests showed that the peak magnitude of a surge can be greater than three times nominal, the observed duration was considerably shorter, on the order of several seconds. The long surge duration assumed in this study has a greater impact on the plenum temperature than the peak magnitude, thus making the maximum TOC estimate conservative. Two models were used to make the necessary calculations to determine the TOC limit

  18. Estimation of the soil-water partition coefficient normalized to organic carbon for ionizable organic chemicals

    DEFF Research Database (Denmark)

    Franco, Antonio; Trapp, Stefan

    2008-01-01

    The sorption of organic electrolytes to soil was investigated. A dataset consisting of 164 electrolytes, composed of 93 acids, 65 bases, and six amphoters, was collected from literature and databases. The partition coefficient log KOW of the neutral molecule and the dissociation constant pKa were...... calculated by the software ACD/Labs®. The Henderson-Hasselbalch equation was applied to calculate dissociation. Regressions were developed to predict separately for the neutral and the ionic molecule species the distribution coefficient (Kd) normalized to organic carbon (KOC) from log KOW and pKa. The log...... KOC of strong acids (pKa correlated to these parameters. The regressions derived for weak acids and bases (undissociated at environmental pH) were similar. The highest sorption was found for strong bases (pKa > 7.5), probably due to electrical interactions. Nonetheless, their log KOC...

  19. Restoration of blood 2,3-diphosphoglycerate levels in multi-transfused patients: effect of organic and inorganic phosphate.

    Science.gov (United States)

    Iapichino, G; Radrizzani, D; Solca, M; Franzosi, M G; Pallavicini, F B; Spina, G; Scherini, A

    1984-01-01

    Blood stored in acid-citrate-dextrose (ACD) shows a progressive decrease in 2,3-diphosphoglycerate (DPG) content. Since the decrease in DPG increases hemoglobin oxygen affinity, which in turn may reduce tissue and venous PO2 and peripheral oxygen delivery, many efforts have been made to preserve or restore DPG levels in stored blood. An in vivo rejuvenating technique, employing fructose-1,6-diphosphate (FDP) at a mean dosage of 1 mmol kg-1 day-1 of phosphate, to increase the DPG circulating level in multi-transfused patients is proposed. Eighteen patients, who received at least one-third of their estimated blood volume (3990 +/- 480 (SEM) ml of ACD stored blood) in blood transfusion, were treated: nine with inorganic phosphate, and nine with FDP. Basal DPG was very low in both groups: 12.61 +/- 1.34 (SEM) and 10.42 +/- 0.98 (SEM) mumol g-1, respectively (normal value is 14.5 mumol g-1, at pH 7.40). However, DPG values increased significantly and promptly in patients receiving FDP, whereas in cases of inorganic phosphate administration, it was not significantly raised over the basal value until the third day. Phosphatemia remained normal and constant with FDP, but it rose significantly on the third day of treatment with inorganic phosphate. FDP appears to consistently and rapidly increase DPG levels after transfusion with blood stored in ACD, and to be particularly safe.

  20. Influence of sample composition on aerosol organic and black carbon determinations

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Corrigan, C.E.

    1995-07-01

    In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550{degrees}C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations.

  1. Influence of sample composition on aerosol organic and black carbon determinations

    International Nuclear Information System (INIS)

    Novakov, T.; Corrigan, C.E.

    1995-07-01

    In this paper we present results on characterization of filter-collected redwood (Sequoia sempevirens)-needle and eucalyptus smoke particles by thermal, optical, and solvent extraction methods. Our results demonstrate that organic and black carbon concentrations determined by thermal and optical methods are not only method dependent, but also critically influenced by the overall chemical composition of the samples. These conclusions are supported by the following: (1) the organic fraction of biomass smoke particles analyzed includes a component, ranging in concentration from about 6-20% of total carbon or from 16-30% of organic carbon, that is relatively non-volatile and has a combustion temperature close to that of black carbon; (2) presence of K or Na in biomass smoke samples lowers the combustion temperatures of this organic component and of black carbon, making their combustion properties indistinguishable; (3) about 20% of total organic material is nonvolatile when heated to 550 degrees C in an inert atmosphere. Consequently, thermal methods that rely on a specific temperature to separate organic from black carbon may either underestimate or overestimate the black and organic carbon concentrations, depending on the amounts of Na and K and on the composition and concentration of organic material present in a sample. These analytical uncertainties and, under some conditions, absorption by organic material may contribute to the variability of empirically derived proportionality between light transmission through filter deposits and black carbon concentrations

  2. Fractionation and characterization of soil organic carbon during transition to organic farming

    Science.gov (United States)

    Abdelrahman, H.; Olk, D.; Cocozza, C.; Miano, T.

    2012-04-01

    The transition from conventional to organic farming is the most difficult period faced by organic growers as it could be characterized by unstable conditions, such as nutrient availability, production reductions, mineralization extents. As soil organic matter (SOM), specifically soil organic carbon (SOC), is known to play important roles in maintenance and improvement of many soil properties, it is important to define its changes during the transition period. Total SOC might not be the suitable tool to track the changes in organically based soil fertility within a 3- to 5-yr transition period. Labile fractions that are important for nutrient cycling and supply are likely to be controlled by management to a much greater extent than is total SOM. Two field experiments, in south of Italy, were established in 2009 to study the changes in SOC during transition to organic farming. Experiments included a cereal/leguminous rotation with triplicates treatments of permitted amendments (compost and fertilizers). Soils were sampled at the beginning of the project, and after each crop harvest in 2010 and 2011. A sequential fractionation procedure was used to separate different SOC-fractions: light fraction (LF), two size classes of particulate organic matter (POM), mobile humic acid (MHA) and Ca++ bound humic acid (CaHA). Isolated fractions were quantified and analyzed for their content of C, N, carbohydrates and amino compounds fingerprints. The obtained results showed that compost application contributed to significantly higher quantities of LF, POM and MHA than did fertilizers application. Carbohydrates content decreased in LF while increased noticeably in POM and slightly in MHA fractions, which indicates that decomposing materials are converted, within the time span of humification, from young fractions into more mature fractions. Amino compounds were found to provide up to 40% of total soil N with a major contribution of the humified fractions, MHA and CaHA. The utilized

  3. Driving forces of organic carbon spatial distribution in the tropical seascape

    Science.gov (United States)

    Gillis, L. G.; Belshe, F. E.; Ziegler, A. D.; Bouma, T. J.

    2017-02-01

    An important ecosystem service of tropical coastal vegetation including seagrass beds and mangrove forests is their ability to accumulate carbon. Here we attempt to establish the driving forces for the accumulation of surface organic carbon in southern Thailand coastal systems. Across 12 sites we found that in line with expectations, seagrass beds (0.6 ± 0.09%) and mangrove forests (0.9 ± 0.3%) had higher organic carbon in the surface (top 5 cm) sediment than un-vegetated mudflats (0.4 ± 0.04%). Unexpectedly, however, mangrove forests in this region retained organic carbon, rather than outwell it, under normal tidal conditions. No relationship was found between organic carbon and substrate grain size. The most interesting finding of our study was that climax and pioneer seagrass species retained more carbon than mixed-species meadows, suggesting that plant morphology and meadow characteristics can be important factors in organic carbon accumulation. Insights such as these are important in developing carbon management strategies involving coastal ecosystems such as offsetting of carbon emissions. The ability of tropical coastal vegetation to sequester carbon is an important aspect for valuing the ecosystems. Our results provide some initial insight into the factors affecting carbon sequestration in these ecosystems, but also highlight the need for further research on a global scale.

  4. Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion.

    Science.gov (United States)

    Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

    2017-05-01

    Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha -1 , were higher than 45.90 Mg C ha -1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

  5. Soil Organic Carbon Fractions and Stocks Respond to Restoration Measures in Degraded Lands by Water Erosion

    Science.gov (United States)

    Nie, Xiaodong; Li, Zhongwu; Huang, Jinquan; Huang, Bin; Xiao, Haibing; Zeng, Guangming

    2017-05-01

    Assessing the degree to which degraded soils can be recovered is essential for evaluating the effects of adopted restoration measures. The objective of this study was to determine the restoration of soil organic carbon under the impact of terracing and reforestation. A small watershed with four typical restored plots (terracing and reforestation (four different local plants)) and two reference plots (slope land with natural forest (carbon-depleted) and abandoned depositional land (carbon-enriched)) in subtropical China was studied. The results showed that soil organic carbon, dissolved organic carbon and microbial biomass carbon concentrations in the surface soil (10 cm) of restored lands were close to that in abandoned depositional land and higher than that in natural forest land. There was no significant difference in soil organic carbon content among different topographic positions of the restored lands. Furthermore, the soil organic carbon stocks in the upper 60 cm soils of restored lands, which were varied between 50.08 and 62.21 Mg C ha-1, were higher than 45.90 Mg C ha-1 in natural forest land. Our results indicated that the terracing and reforestation could greatly increase carbon sequestration and accumulation and decrease carbon loss induced by water erosion. And the combination measures can accelerate the restoration of degraded soils when compared to natural forest only. Forest species almost have no impact on the total amount of soil organic carbon during restoration processes, but can significantly influence the activity and stability of soil organic carbon. Combination measures which can provide suitable topography and continuous soil organic carbon supply could be considered in treating degraded soils caused by water erosion.

  6. Autochthonous and allochthonous contributions of organic carbon to microbial food webs in Svalbard fjords

    NARCIS (Netherlands)

    Holding, Johnna M.; Duarte, Carlos M.; Delgado-Huertas, Antonio; Soetaert, Karline; Vonk, Jorien E.; Agustí, Susana; Wassmann, Paul; Middelburg, Jack J.

    2017-01-01

    Rising temperatures in the Arctic Ocean are causing sea ice and glaciers to melt at record breaking rates, which has consequences for carbon cycling in the Arctic Ocean that are yet to be fully understood. Microbial carbon cycling is driven by internal processing of in situ produced organic carbon

  7. Autochthonous and allochthonous contributions of organic carbon to microbial food webs in Svalbard fjords

    NARCIS (Netherlands)

    Holding, Johna M.; Duarte, Carlos M.; Delgado-Huertas, Antonio; Soetaert, Karline; Vonk, Jorien E.; Agusti, Susana; Wassmann, Paul; Middelburg, Jack J.

    Rising temperatures in the Arctic Ocean are causing sea ice and glaciers to melt at record breaking rates, which has consequences for carbon cycling in the Arctic Ocean that are yet to be fully understood. Microbial carbon cycling is driven by internal processing of in situ produced organic carbon

  8. Pesticide sorption by low organic carbon sediments: A sceening for seven herbicides

    DEFF Research Database (Denmark)

    Madsen, Lene; Lindhardt, Bo; Rosenberg, Per

    2000-01-01

    The sorption of seven pesticides in 10 Danish aquifer sediments has been studied. These sediments all have a total organic carbon (TOC) content below 1 g kg(-1), and include carbonate-bearing and carbonate-free Quatenary sand deposits and a Cretaceous chalk aquifer. Batch experiments were carried...

  9. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    Haas, H. de

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (C02 ) is one of the major contributors to the natural greenhouse

  10. Transport, preservation and accumulation of organic carbon in the North Sea

    NARCIS (Netherlands)

    de Haas, H.

    1997-01-01

    This thesis contains the results of the research on the burial of organic carbon in the North Sea as it was carried out at the Netherlands Institute for Sea Research in the period 1993-1997. Carbon in the form of carbon dioxide (CO2 ) is one of the major contributors to the natural greenhouse

  11. Linking variability in soil solution dissolved organic carbon to climate, soil type, and vegetation type

    NARCIS (Netherlands)

    Camino-Serrano, Marta; Gielen, Bert; Luyssaert, Sebastiaan; Ciais, Philippe; Vicca, Sara; Guenet, Bertrand; Vos, Bruno De; Cools, Nathalie; Ahrens, Bernhard; Altaf Arain, M.; Borken, Werner; Clarke, Nicholas; Clarkson, Beverley; Cummins, Thomas; Don, Axel; Pannatier, Elisabeth Graf; Laudon, Hjalmar; Moore, Tim; Nieminen, Tiina M.; Nilsson, Mats B.; Peichl, Matthias; Schwendenmann, Luitgard; Siemens, Jan; Janssens, Ivan

    2014-01-01

    Lateral transport of carbon plays an important role in linking the carbon cycles of terrestrial and aquatic ecosystems. There is, however, a lack of information on the factors controlling one of the main C sources of this lateral flux, i.e., the concentration of dissolved organic carbon (DOC) in

  12. Microporous metal-organic framework with potential for carbon dioxide capture at ambient conditions

    NARCIS (Netherlands)

    Xiang, S.C.; He, Y.; Zhang, Z.; Wu, H.; Zhou, W.; Krishna, R.; Chen, B.

    2012-01-01

    Carbon dioxide capture and separation are important industrial processes that allow the use of carbon dioxide for the production of a range of chemical products and materials, and to minimize the effects of carbon dioxide emission. Porous metal-organic frameworks are promising materials to achieve

  13. Statistics provide guidance for indigenous organic carbon detection on Mars missions.

    Science.gov (United States)

    Sephton, Mark A; Carter, Jonathan N

    2014-08-01

    Data from the Viking and Mars Science Laboratory missions indicate the presence of organic compounds that are not definitively martian in origin. Both contamination and confounding mineralogies have been suggested as alternatives to indigenous organic carbon. Intuitive thought suggests that we are repeatedly obtaining data that confirms the same level of uncertainty. Bayesian statistics may suggest otherwise. If an organic detection method has a true positive to false positive ratio greater than one, then repeated organic matter detection progressively increases the probability of indigeneity. Bayesian statistics also reveal that methods with higher ratios of true positives to false positives give higher overall probabilities and that detection of organic matter in a sample with a higher prior probability of indigenous organic carbon produces greater confidence. Bayesian statistics, therefore, provide guidance for the planning and operation of organic carbon detection activities on Mars. Suggestions for future organic carbon detection missions and instruments are as follows: (i) On Earth, instruments should be tested with analog samples of known organic content to determine their true positive to false positive ratios. (ii) On the mission, for an instrument with a true positive to false positive ratio above one, it should be recognized that each positive detection of organic carbon will result in a progressive increase in the probability of indigenous organic carbon being present; repeated measurements, therefore, can overcome some of the deficiencies of a less-than-definitive test. (iii) For a fixed number of analyses, the highest true positive to false positive ratio method or instrument will provide the greatest probability that indigenous organic carbon is present. (iv) On Mars, analyses should concentrate on samples with highest prior probability of indigenous organic carbon; intuitive desires to contrast samples of high prior probability and low prior

  14. Modeling equilibrium adsorption of organic micropollutants onto activated carbon

    KAUST Repository

    De Ridder, David J.; Villacorte, Loreen O.; Verliefde, Arne R. D.; Verberk, Jasper Q J C; Heijman, Bas G J; Amy, Gary L.; Van Dijk, Johannis C.

    2010-01-01

    to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon

  15. Tritium distribution ratios between the 30 % tributyl phosphate(TBP)-normal dodecane(nDD) organic phase and uranyl nitrate-nitric acid aqueous phase

    International Nuclear Information System (INIS)

    Fujine, Sachio; Uchiyama, Gunzou; Sugikawa, Susumu; Maeda, Mitsuru; Tsujino, Takeshi.

    1989-10-01

    Tritium distribution ratios between the organic and aqueous phases were measured for the system of 30 % tributyl phosphate(TBP)-normal dodecane(nDD)/uranyl nitrate-nitric acid water. It was confirmed that tritium is extracted by TBP into the organic phase in both chemical forms of tritiated water (HTO) and tritiated nitric acid (TNO 3 ). The value of tritium distribution ratio ranged from 0.002 to 0.005 for the conditions of 0-6 mol/L nitric acid, 0.5-800 mCi/L tritium in aqueous phase, and 0-125 g-U/L uranium in organic phase. Isotopic distribution coefficient of tritium between the organic and aqueous phases was observed to be about 0.95. (author)

  16. Factors for Microbial Carbon Sources in Organic and Mineral Soils from Eastern United States Deciduous Forests

    Energy Technology Data Exchange (ETDEWEB)

    Stitt, Caroline R. [Mills College, Oakland, CA (United States)

    2013-09-16

    Forest soils represent a large portion of global terrestrial carbon; however, which soil carbon sources are used by soil microbes and respired as carbon dioxide (CO2) is not well known. This study will focus on characterizing microbial carbon sources from organic and mineral soils from four eastern United States deciduous forests using a unique radiocarbon (14C) tracer. Results from the dark incubation of organic and mineral soils are heavily influenced by site characteristics when incubated at optimal microbial activity temperature. Sites with considerable differences in temperature, texture, and location differ in carbon source attribution, indicating that site characteristics play a role in soil respiration.

  17. Magnetic Particle-Based Immunoassay of Phosphorylated p53 Using Protein-Cage Templated Lead Phosphate and Carbon Nanospheres for Signal Amplification

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Aiqiong; Bao, Yuanwu; Ge, Xiaoxiao; Shin, Yongsoon; Du, Dan; Lin, Yuehe

    2012-11-20

    Phosphorylated p53 at serin 15 (phospho-p53-15) is a potential biomarker of Gamma-radiation exposure. In this paper, we described a new magnetic particles (MPs)-based electrochemical immunoassay of human phospho-p53-15 using carbon nanospheres (CNS) and protein-cage templated lead phosphate nanoparticles for signal amplification. Greatly enhanced sensitivity was achieved by three aspects: 1) The protein-cage nanoparticle (PCN) and p53-15 signal antibody (p53-15 Ab2) are linked to CNS (PCNof each apoferritin; 3) MPs capture a large amount of primary antibodies. Using apoferritin templated metallic phosphate instead of enzyme as label has the advantage of eliminating the addition of mediator or immunoreagents and thus makes the immunoassay system simpler. The subsequent stripping voltammetric analysis of the released lead ions were detected on a disposable screen printed electrode. The response current was proportional to the phospho-p53-15 concentration in the range of 0.02 to 20 ng mL-1 with detection limit of 0.01 ng mL-1. This method shows a good stability, reproducibility and recovery.

  18. Process based modelling of soil organic carbon redistribution on landscape scale

    Science.gov (United States)

    Schindewolf, Marcus; Seher, Wiebke; Amorim, Amorim S. S.; Maeso, Daniel L.; Jürgen, Schmidt

    2014-05-01

    Recent studies have pointed out the great importance of erosion processes in global carbon cycling. Continuous erosion leads to a massive loss of top soils including the loss of organic carbon accumulated over long time in the soil humus fraction. Lal (2003) estimates that 20% of the organic carbon eroded with top soils is emitted into atmosphere, due to aggregate breakdown and carbon mineralization during transport by surface runoff. Furthermore soil erosion causes a progressive decrease of natural soil fertility, since cation exchange capacity is associated with organic colloids. As a consequence the ability of soils to accumulate organic carbon is reduced proportionately to the drop in soil productivity. The colluvial organic carbon might be protected from further degradation depending on the depth of the colluvial cover and local decomposing conditions. Some colluvial sites can act as long-term sinks for organic carbon. The erosional transport of organic carbon may have an effect on the global carbon budget, however, it is uncertain, whether erosion is a sink or a source for carbon in the atmosphere. Another part of eroded soils and organic carbon will enter surface water bodies and might be transported over long distances. These sediments might be deposited in the riparian zones of river networks. Erosional losses of organic carbon will not pass over into atmosphere for the most part. But soil erosion limits substantially the potential of soils to sequester atmospheric CO2 by generating humus. The present study refers to lateral carbon flux modelling on landscape scale using the process based EROSION 3D soil loss simulation model, using existing parameter values. The selective nature of soil erosion results in a preferentially transport of fine particles while less carbonic larger particles remain on site. Consequently organic carbon is enriched in the eroded sediment compared to the origin soil. For this reason it is essential that EROSION 3D provides the

  19. Simultaneous effect of dissolved organic carbon, surfactant, and organic acid on the desorption of pesticides investigated by response surface methodology

    DEFF Research Database (Denmark)

    Trinh, Ha Thu; Duong, Hanh Thi; Ta, Thao Thi

    2017-01-01

    Desorption of pesticides (fenobucarb, endosulfan, and dichlorodiphenyltrichloroethane (DDT)) from soil to aqueous solution with the simultaneous presence of dissolved organic carbon (DOC), sodium dodecyl sulfate (SDS), and sodium oxalate (Oxa) was investigated in batch test by applying a full...

  20. Evaluation and control of poisoning of impregnated carbons used for organic iodide removal

    International Nuclear Information System (INIS)

    Kovach, J.L.; Rankovic, L.

    1979-01-01

    By the evaluation of the chemical reactions which have taken place on impregnated activated carbon surfaces exposed to nuclear reactor atmospheric environments, the role of various impregnants has been studied. The evaluation shows several different paths for the aging and posioning to take place. The four major causes were found to be: organic solvent contamination; inorganic acid gas contamination; formation of organic acids on carbon surface; and, formation of SO 2 from carbon sulfur content. Prevention of poisoning by the first two paths can be accomplished only by procedural changes within the facility. However the last three poisoning paths can be controlled to some extent by the selection of carbon pretreatment techniques and the type of impregnant used. Results were generated by evaluating used carbons from 14 nuclear power plants and by artificial poisoning of laboratory impregnated carbons. Impregnants which have antioxidant properties, besides reaction with organic iodides, can increase the life of the impregnated activated carbons

  1. Organic carbonates: experiment and ab initio calculations for prediction of thermochemical properties.

    Science.gov (United States)

    Verevkin, Sergey P; Emel'yanenko, Vladimir N; Kozlova, Svetlana A

    2008-10-23

    This work has been undertaken in order to obtain data on thermodynamic properties of organic carbonates and to revise the group-additivity values necessary for predicting their standard enthalpies of formation and enthalpies of vaporization. The standard molar enthalpies of formation of dibenzyl carbonate, tert-butyl phenyl carbonate, and diphenyl carbonate were measured using combustion calorimetry. Molar enthalpies of vaporization of these compounds were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. Molar enthalpy of sublimation of diphenyl carbonate was measured in the same way. Ab initio calculations of molar enthalpies of formation of organic carbonates have been performed using the G3MP2 method, and results are in excellent agreement with the available experiment. Then the group-contribution method has been developed to predict values of the enthalpies of formation and enthalpies of vaporization of organic carbonates.

  2. Recovering phosphorus and uranium values from phosphate rock

    International Nuclear Information System (INIS)

    Sze, M.C.Y.; Long, R.H.

    1981-01-01

    Phosphate rock is acidulated with aqueous nitric acid to produce an aqueous solution containing phosphate values, calcium and uranium values. The aqueous solution is contacted with an extraction solvent for the uranium values: the extraction solvent comprising a water immiscible organic diluent, a dialkyl phosphoric acid having at least 10 carbon atoms, and an organic phosphorus compound having the formula R 1 R 2 R 3 P = O where R 1 , R 2 and R 3 are each either alkyl or alkoxy, the organic phosphorus compound having at least 10 carbon atoms. The uranium values are then recovered from the extraction solvent. In an example the extraction solvent is HDEHP and TOPO in kerosene. (author)

  3. Recovering phosphorus and uranium values from phosphate rock

    Energy Technology Data Exchange (ETDEWEB)

    Sze, M C.Y.; Long, R H

    1981-02-11

    Phosphate rock is acidulated with aqueous nitric acid to produce an aqueous solution containing phosphate values, calcium and uranium values. The aqueous solution is contacted with an extraction solvent for the uranium values: the extraction solvent comprising a water immiscible organic diluent, a dialkyl phosphoric acid having at least 10 carbon atoms, and an organic phosphorus compound having the formula R/sub 1/ R/sub 2/ R/sub 3/ P = O where R/sub 1/, R/sub 2/ and R/sub 3/ are each either alkyl or alkoxy, the organic phosphorus compound having at least 10 carbon atoms. The uranium values are then recovered from the extraction solvent. In an example the extraction solvent is HDEHP and TOPO in kerosene.

  4. [Effects of Chinese prickly ash orchard on soil organic carbon mineralization and labile organic carbon in karst rocky desertification region of Guizhou province].

    Science.gov (United States)

    Zhang, Wen-Juan; Liao, Hong-Kai; Long, Jian; Li, Juan; Liu, Ling-Fei

    2015-03-01

    Taking 5-year-old Chinese prickly ash orchard (PO-5), 17-year-old Chinese prickly ash orchard (PO- 17), 30-year-old Chinese prickly ash orchard (PO-30) and the forest land (FL, about 60 years) in typical demonstration area of desertification control test in southwestern Guizhou as our research objects, the aim of this study using a batch incubation experiment was to research the mineralization characteristics of soil organic carbon and changes of the labile soil organic carbon contents at different depths (0-15 cm, 15-30 cm, and 30-50 cm). The results showed that: the cumulative mineralization amounts of soil organic carbon were in the order of 30-year-old Chinese prickly ash orchard, the forest land, 5-year-old Chinese prickly ash orchard and 17-year-old Chinese prickly ash orchard at corresponding depth. Distribution ratios of CO2-C cumulative mineralization amount to SOC contents were higher in Chinese prickly ash orchards than in forest land at each depth. Cultivation of Chinese prickly ash in long-term enhanced the mineralization of soil organic carbon, and decreased the stability of soil organic carbon. Readily oxidized carbon and particulate organic carbon in forest land soils were significantly more than those in Chinese prickly ash orchards at each depth (P < 0.05). With the increasing times of cultivation of Chinese prickly ash, the contents of readily oxidized carbon and particulate organic carbon first increased and then declined at 0-15 cm and 15-30 cm depth, respectively, but an opposite trend was found at 30-50 cm depth. At 0-15 cm and 15-30 cm, cultivation of Chinese prickly ash could be good for improving the contents of labile soil organic carbon in short term, but it was not conducive in long-term. In this study, we found that cultivation of Chinese prickly ash was beneficial for the accumulation of labile organic carbon at the 30-50 cm depth.

  5. Biomimetic synthesis of needle-like fluorescent calcium phosphate/carbon dot hybrid composites for cell labeling and copper ion detection.

    Science.gov (United States)

    Guo, Shanshan; Lu, Shousi; Xu, Pingxiang; Ma, Yi; Zhao, Liang; Zhao, Yuming; Gu, Wei; Xue, Ming

    2016-05-04

    Herein, we report a biomimetic method to synthesize needle-like calcium phosphate (CaP) with dimensions of ∼130 nm length and ∼30 nm width using carbon dots (CDs) and sodium carboxymethylcellulose as dual templates. In addition to acting as the template, the CDs enable the CaP/CDs hybrid composites to emit blue fluorescence under UV excitation. Moreover, the prepared CaP/CDs exhibited a negligible cytotoxicity towards HeLa cells. The potential of these CaP/CDs as a fluorescent probe for cell labeling was tested. In addition, it was demonstrated that the CaP/CDs were capable of selective detection of copper ions in drinking water.

  6. Incorporation of /sup 14/C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication

    Energy Technology Data Exchange (ETDEWEB)

    Sikorska, M; Gorzkowski, B; Szumanska, G; Smialek, M [Polska Akademia Nauk, Warsaw. Centrum Medycyny Doswiadczalnej i Klinicznej; Panstwowy Zaklad Higieny, Warsaw (Poland))

    1975-01-01

    Incorporation of /sup 14/C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication was studied. In brains of rats tested on the 20, 30 and 60th minute of exposure to CO and immediately after removal from the chamber the enzyme activity showed no essential deviation from the control level. In the group of rats tested 1 hour after taking them out from the chamber increase of the enzyme activity was noticed, amounting to about 33% of the control value. The brains tested 24 hours after exposure showed the largest increase of the enzyme activity by about 94%. In the next time periods, 48 and 72 hours after intoxication, the enzyme activity was decreasing. The glycogen content in brains of control animals increased 3 hours after CO intoxication by about 69%. The increase of glycogen synthesis was expressed by increase of the total radioactivity, which amounted to 160% of the control value.

  7. Dynamics of organic and inorganic carbon across contiguous mangrove and seagrass systems (Gazi Bay, Kenya)

    NARCIS (Netherlands)

    Bouillon, S.; Dehairs, F.; Velimirov, B.; Abril, G.; Borges, A.V.

    2007-01-01

    We report on the water column biogeochemistry in adjacent mangrove and seagrass systems in Gazi Bay (Kenya), with a focus on assessing the sources and cycling of organic and inorganic carbon. Mangrove and seagrass-derived material was found to be the dominant organic carbon sources in the water

  8. Nonconservative behavior of dissolved organic carbon across the Laptev and East Siberian seas

    NARCIS (Netherlands)

    Alling, Vanja; Sanchez-Garcia, Laura; Porcelli, Don; Pugach, Sveta; Vonk, Jorien E.; Van Dongen, Bart; Mörth, Carl Magnus; Anderson, Leif G.; Sokolov, Alexander; Andersson, Per; Humborg, Christoph; Semiletov, Igor P.; Gustafsson, Örjan

    2010-01-01

    Climate change is expected to have a strong effect on the Eastern Siberian Arctic Shelf (ESAS) region, which includes 40% of the Arctic shelves and comprises the Laptev and East Siberian seas. The largest organic carbon pool, the dissolved organic carbon (DOC), may change significantly due to

  9. Biochemical and stable carbon isotope records of mangrove derived organic matter in the sediment cores

    Digital Repository Service at National Institute of Oceanography (India)

    Manju, M.N.; Resmi, P.; RatheeshKumar, C.S.; Gireeshkumar, T.R.; Chandramohanakumar, N.; Joseph, M.M.

    in mangrove sediments. This also confirms the involvement of heterotrophic microorganisms in the organic carbon dynamics of the study area. The bulk elemental ratio (total organic carbon/total nitrogen) varied between 11.39 and 24.14 in the study region...

  10. Selective extraction methods for aluminium, iron and organic carbon from montane volcanic ash soils

    NARCIS (Netherlands)

    Jansen, B.; Tonneijck, F.H.; Verstraten, J.M.

    2011-01-01

    Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle. Given the central role of Al and Fe in stabilizing organic matter in volcanic ash soils, we assessed various extraction methods of Al, Fe, and

  11. Mercury and Organic Carbon Relationships in Streams Draining Forested Upland/Peatland Watersheds

    Science.gov (United States)

    R. K. Kolka; D. F. Grigal; E. S. Verry; E. A. Nater

    1999-01-01

    We determined the fluxes of total mecury (HgT), total organic carbon (TOC), and dissolved organic carbon (DOC) from five upland/peatland watersheds at the watershed outlet. The difference between TOC and DOC was defined as particulate OC (POC). Concentrations of HgT showed moderate to strong relationships with POC (R2 = 0.77) when all watersheds...

  12. Soil Organic Matter Accumulation and Carbon Fractions along a Moisture Gradient of Forest Soils

    Directory of Open Access Journals (Sweden)

    Ewa Błońska

    2017-11-01

    Full Text Available The aim of the study was to present effects of soil properties, especially moisture, on the quantity and quality of soil organic matter. The investigation was performed in the Czarna Rózga Reserve in Central Poland. Forty circular test areas were located in a regular grid of points (100 × 300 m. Each plot was represented by one soil profile located at the plot’s center. Sample plots were located in the area with Gleysols, Cambisols and Podzols with the water table from 0 to 100 cm. In each soil sample, particle size, total carbon and nitrogen content, acidity, base cations content and fractions of soil organic matter were determined. The organic carbon stock (SOCs was calculated based on its total content at particular genetic soil horizons. A Carbon Distribution Index (CDI was calculated from the ratio of the carbon accumulation in organic horizons and the amount of organic carbon accumulation in the mineral horizons, up to 60 cm. In the soils under study, in the temperate zone, moisture is an important factor in the accumulation of organic carbon in the soil. The highest accumulation of carbon was observed in soils of swampy variant, while the lowest was in the soils of moist variant. Large accumulation of C in the soils with water table 80–100 cm results from the thick organic horizons that are characterized by lower organic matter decomposition and higher acidity. The proportion of carbon accumulation in the organic horizons to the total accumulation in the mineral horizons expresses the distribution of carbon accumulated in the soil profile, and is a measure of quality of the organic matter accumulated. Studies have confirmed the importance of moisture content in the formation of the fractional organic matter. With greater soil moisture, the ratio of humic to fulvic acids (HA/FA decreases, which may suggest an increase in carbon mobility in soils.

  13. Dissolved inorganic carbon and organic carbon in mires in the Forsmark area. A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Anders [EcoAnalytica, Haegersten (Sweden)

    2011-12-15

    Dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) are the large dissolved carbon pools in mires. They are both related to a number of factors such as groundwater flow, minerogenic influence and peat properties, which all are more or less related to peatland development stage. In a scenario of a release of radionuclides from an underground repository containing radioactive material, behaviour of these pools during the mire ontogeny will be of importance for the understanding of how C-14 will constitute a potential risk to humans and non-human biota. In this pilot study, DIC and DOC concentrations were investigated for three mires representing a potential sequence of peatland development in a coastal area at Forsmark in central Sweden characterized by land upheaval, a flat topography and calcareous content in the soil. The mires where chosen based on difference in height above the sea level, covering approximate 1000 years, and characteristics based on their vegetation. Water samples were collected during August from all three mires at two different depths in the anoxic layer of the mires, by extracting water from peat obtained with a peat corer. DIC concentrations where related to the age of the mires, with the lowest concentrations in the highest located mire. There was a positive correlation between pH and DIC, where the higher DIC concentrations were found in the 'richer' fens. DIC concentrations were also positively related to the conductivity within and between the mires, where conductivity would be a proxy for the dominating cation Ca{sup 2+} associated to the calcareous-influenced groundwater. DOC concentrations were highest in the oldest mire, but were similar in the younger mires. No patterns were found between DIC and DOC, and the peat bulk density. The report ends with suggestions on how a continued study could be improved.

  14. Dissolved inorganic carbon and organic carbon in mires in the Forsmark area. A pilot study

    International Nuclear Information System (INIS)

    Loefgren, Anders

    2011-12-01

    Dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) are the large dissolved carbon pools in mires. They are both related to a number of factors such as groundwater flow, minerogenic influence and peat properties, which all are more or less related to peatland development stage. In a scenario of a release of radionuclides from an underground repository containing radioactive material, behaviour of these pools during the mire ontogeny will be of importance for the understanding of how C-14 will constitute a potential risk to humans and non-human biota. In this pilot study, DIC and DOC concentrations were investigated for three mires representing a potential sequence of peatland development in a coastal area at Forsmark in central Sweden characterized by land upheaval, a flat topography and calcareous content in the soil. The mires where chosen based on difference in height above the sea level, covering approximate 1000 years, and characteristics based on their vegetation. Water samples were collected during August from all three mires at two different depths in the anoxic layer of the mires, by extracting water from peat obtained with a peat corer. DIC concentrations where related to the age of the mires, with the lowest concentrations in the highest located mire. There was a positive correlation between pH and DIC, where the higher DIC concentrations were found in the 'richer' fens. DIC concentrations were also positively related to the conductivity within and between the mires, where conductivity would be a proxy for the dominating cation Ca 2+ associated to the calcareous-influenced groundwater. DOC concentrations were highest in the oldest mire, but were similar in the younger mires. No patterns were found between DIC and DOC, and the peat bulk density. The report ends with suggestions on how a continued study could be improved

  15. AC-driven organic light emission devices with carbon nanotubes

    Science.gov (United States)

    Jeon, So-Yeon; Yu, SeGi

    2017-02-01

    We have investigated alternating current (AC)-driven organic light-emitting devices (OLEDs), with carbon nanotubes (CNTs) incorporated within the emission layer. With CNT incorporation, the brightness of the OLEDs was substantially improved, and the turn-on voltage was reduced by at least a factor of five. Furthermore, the current levels of the CNT-incorporated OLEDs were lower than that of the reference device. A roughly 70% decrease in the current level was obtained for a CNT concentration of 0.03 wt%. This was accomplished by keeping the concentration of CNTs low and the length of CNTs short, which helped to suppress the percolation networking of CNTs within the emitting layer. Strong local electric fields near the end-tips of CNTs and micro-capacitors formed by dispersed CNTs might have caused this high brightness and these low currents. CNT incorporation in the emitting layer can improve the characteristics of AC-driven OLEDs, which are considered to be one of the candidates for flat panel displays and lightning devices.

  16. Resonance Raman spectroscopy of volatile organics -- Carbon tetrachloride

    International Nuclear Information System (INIS)

    Barletta, R.E.; Veligdan, J.T.

    1994-09-01

    Volatile organic chemicals are a class of pollutants which are regulated at very low levels by the EPA. Consequently a need exists as a part of site remediation efforts within DOE to develop technologies which will allow for the in situ monitoring of these chemicals. Resonance Raman spectroscopy is a potential technique to accomplish this if the resonance enhancement is sufficiently high. Carbon tetrachloride was selected as a test case. Measurements under resonance conditions at 248 nm showed an enhancement factor of 2 x 10 4 . Using this value an estimate of the sensitivity for both in situ and remote monitoring of CCl 4 was made. It was concluded that resonance Raman could be used to detect these chemicals at levels of regulatory interest. Future effort directed towards the development of a suitable probe as well as a field-portable system would be desirable. Such effort could be directed towards the solution of a particular monitoring problem within a DOE waste remediation project. Once developed, however, it should be easily generalized to the analysis of other VOC's in other environments

  17. AC-driven Organic Light Emission Devices with Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, So-Yeon [Sungkyunkwan University, Suwon (Korea, Republic of); Yu, SeGi [Hankuk University of Foreign Studies, Yongin (Korea, Republic of)

    2017-02-15

    We have investigated alternating current (AC)-driven organic light-emitting devices (OLEDs), with carbon nanotubes (CNTs) incorporated within the emission layer. With CNT incorporation, the brightness of the OLEDs was substantially improved, and the turn-on voltage was reduced by at least a factor of five. Furthermore, the current levels of the CNT-incorporated OLEDs were lower than that of the reference device. A roughly 70% decrease in the current level was obtained for a CNT concentration of 0.03 wt%. This was accomplished by keeping the concentration of CNTs low and the length of CNTs short, which helped to suppress the percolation networking of CNTs within the emitting layer. Strong local electric fields near the end-tips of CNTs and micro-capacitors formed by dispersed CNTs might have caused this high brightness and these low currents. CNT incorporation in the emitting layer can improve the characteristics of AC-driven OLEDs, which are considered to be one of the candidates for flat panel displays and lightning devices.

  18. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures

    Directory of Open Access Journals (Sweden)

    Sundes Fakher

    2016-09-01

    Full Text Available The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs, metal–insulator–semiconductor (MIS and thin film transistor (TFT structures, using poly(methyl methacrylate (PMMA as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance–voltage (C–V for MIS structures, as well as output and transfer characteristics for transistors. Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses, the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states.

  19. Input of particulate organic and dissolved inorganic carbon from the Amazon to the Atlantic Ocean

    OpenAIRE

    Druffel, E. R. M; Bauer, J. E; Griffin, S.

    2005-01-01

    We report concentrations and isotope measurements (radiocarbon and stable carbon) of dissolved inorganic carbon (DIC) and suspended particulate organic carbon (POC) in waters collected from the mouth of the Amazon River and the North Brazil Current. Samples were collected in November 1991, when the Amazon hydrograph was at its annual minimum and the North Brazil Current had retroflected into the equatorial North Atlantic. The DIC Δ14C results revealed postbomb carbon in river and ocean waters...

  20. Critical carbon input to maintain current soil organic carbon stocks in global wheat systems.

    Science.gov (United States)

    Wang, Guocheng; Luo, Zhongkui; Han, Pengfei; Chen, Huansheng; Xu, Jingjing

    2016-01-13

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1° × 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha(-1) yr(-1), with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  1. Quantified carbon input for maintaining existing soil organic carbon stocks in global wheat systems

    Science.gov (United States)

    Wang, G.

    2017-12-01

    Soil organic carbon (SOC) dynamics in croplands is a crucial component of global carbon (C) cycle. Depending on local environmental conditions and management practices, typical C input is generally required to reduce or reverse C loss in agricultural soils. No studies have quantified the critical C input for maintaining SOC at global scale with high resolution. Such information will provide a baseline map for assessing soil C dynamics under potential changes in management practices and climate, and thus enable development of management strategies to reduce C footprint from farm to regional scales. We used the soil C model RothC to simulate the critical C input rates needed to maintain existing soil C level at 0.1°× 0.1° resolution in global wheat systems. On average, the critical C input was estimated to be 2.0 Mg C ha-1 yr-1, with large spatial variability depending on local soil and climatic conditions. Higher C inputs are required in wheat system of central United States and western Europe, mainly due to the higher current soil C stocks present in these regions. The critical C input could be effectively estimated using a summary model driven by current SOC level, mean annual temperature, precipitation, and soil clay content.

  2. Assessment of bacterial growth and total organic carbon removal on granular activated carbon contactors.

    Science.gov (United States)

    Bancroft, K; Maloney, S W; McElhaney, J; Suffet, I H; Pipes, W O

    1983-01-01

    The overall growth rate of bacteria on granular activated carbon (GAC) contactors at the Philadelphia Torresdale Water Treatment Pilot Plant facility was found to decrease until steady state was reached. The growth rate was found to fluctuate between 6.94 X 10(-3) and 8.68 X 10(-4) doublings per h. The microbiological removal of total organic carbon (TOC) was calculated by considering the GAC contactors as semiclosed continuous culture systems and using growth yield factors determined in laboratory experiments. After ozonation, the average TOC entering the contactors was 1,488 micrograms/liter, and the average effluent TOC was 497 micrograms/liter. Microbiological TOC removal was found to average 240 micrograms/liter on GAC contactors, which was not significantly different from microbiological TOC (220 micrograms/liter) removal across a parallel sand contactor where no adsorption took place. Thus, GAC did not appear to enhance biological TOC removal. Bacterial growth and maintenance was responsible for approximately 24% of the TOC removal on GAC under the conditions of this study. PMID:6639023

  3. Adsorption and bioadsorption of granular activated carbon (GAC) for dissolved organic carbon (DOC) removal in wastewater.

    Science.gov (United States)

    Xing, W; Ngo, H H; Kim, S H; Guo, W S; Hagare, P

    2008-12-01

    In this study, the performances of GAC adsorption and GAC bioadsorption in terms of dissolved organic carbon (DOC) removal were investigated with synthetic biologically treated sewage effluent (BTSE), synthetic primary treated sewage effluent (PTSE), real BTSE and real PTSE. The main aims of this study are to verify and compare the efficiency of DOC removal by GAC (adsorption) and acclimatized GAC (bioadsorption). The results indicated that the performance of bioadsorption was significantly better than that of adsorption in all cases, showing the practical use of biological granular activated carbon (BGAC) in filtration process. The most significance was observed at a real PTSE with a GAC dose of 5g/L, having 54% and 96% of DOC removal by adsorption and bioadsorption, respectively. In addition, it was found that GAC adsorption equilibrium was successfully predicted by a hybrid Langmuir-Freundlich model whilst integrated linear driving force approximation (LDFA)+hybrid isotherm model could describe well the adsorption kinetics. Both adsorption isotherm and kinetic coefficients determined by these models will be useful to model the adsorption/bioadsorption process in DOC removal of BGAC filtration system.

  4. Assessment of bacterial growth and total organic carbon removal on granular activated carbon contactors.

    Science.gov (United States)

    Bancroft, K; Maloney, S W; McElhaney, J; Suffet, I H; Pipes, W O

    1983-09-01

    The overall growth rate of bacteria on granular activated carbon (GAC) contactors at the Philadelphia Torresdale Water Treatment Pilot Plant facility was found to decrease until steady state was reached. The growth rate was found to fluctuate between 6.94 X 10(-3) and 8.68 X 10(-4) doublings per h. The microbiological removal of total organic carbon (TOC) was calculated by considering the GAC contactors as semiclosed continuous culture systems and using growth yield factors determined in laboratory experiments. After ozonation, the average TOC entering the contactors was 1,488 micrograms/liter, and the average effluent TOC was 497 micrograms/liter. Microbiological TOC removal was found to average 240 micrograms/liter on GAC contactors, which was not significantly different from microbiological TOC (220 micrograms/liter) removal across a parallel sand contactor where no adsorption took place. Thus, GAC did not appear to enhance biological TOC removal. Bacterial growth and maintenance was responsible for approximately 24% of the TOC removal on GAC under the conditions of this study.

  5. Grasslands and Croplands Have Different Microbial Biomass Carbon Levels per Unit of Soil Organic Carbon

    Directory of Open Access Journals (Sweden)

    Terence P. McGonigle

    2017-07-01

    Full Text Available Primarily using cropped systems, previous studies have reported a positive linear relationship between microbial biomass carbon (MBC and soil organic carbon (SOC. We conducted a meta-analysis to explore this relationship separately for grasslands and croplands using available literature. Studies were limited to those using fumigation–extraction for MBC for field samples. Trials were noted separately where records were distinct in space or time. Grasslands were naturally occurring, restored, or seeded. Cropping systems were typical of the temperate zone. MBC had a positive linear response to increasing SOC that was significant in both grasslands (p < 0.001; r2 = 0.76 and croplands (p < 0.001; r2 = 0.48. However, MBC increased 2.5-fold more steeply per unit of increasing SOC for grassland soils, as compared to the corresponding response in cropland soils. Expressing MBC as a proportion of SOC across the regression overall, slopes corresponded to 2.7% for grasslands and 1.1% for croplands. The slope of the linear relationship for grasslands was significantly (p = 0.0013 steeper than for croplands. The difference between the two systems is possibly caused by a greater proportion of SOC in grasslands being active rather than passive, relative to that in croplands, with that active fraction promoting the formation of MBC.

  6. Adsorption of volatile organic compounds by pecan shell- and almond shell-based granular activated carbons.

    Science.gov (United States)

    Bansode, R R; Losso, J N; Marshall, W E; Rao, R M; Portier, R J

    2003-11-01

    The objective of this research was to determine the effectiveness of using pecan and almond shell-based granular activated carbons (GACs) in the adsorption of volatile organic compounds (VOCs) of health concern and known toxic compounds (such as bromo-dichloromethane, benzene, carbon tetrachloride, 1,1,1-trichloromethane, chloroform, and 1,1-dichloromethane) compared to the adsorption efficiency of commercially used carbons (such as Filtrasorb 200, Calgon GRC-20, and Waterlinks 206C AW) in simulated test medium. The pecan shell-based GACs were activated using steam, carbon dioxide or phosphoric acid. An almond shell-based GAC was activated with phosphoric acid. Our results indicated that steam- or carbon dioxide-activated pecan shell carbons were superior in total VOC adsorption to phosphoric acid-activated pecan shell or almond shell carbons, inferring that the method of activation selected for the preparation of activated carbons affected the adsorption of VOCs and hence are factors to be considered in any adsorption process. The steam-activated, pecan shell carbon adsorbed more total VOCs than the other experimental carbons and had an adsorption profile similar to the two coconut shell-based commercial carbons, but had greater adsorption than the coal-based commercial carbon. All the carbons studied adsorbed benzene more effectively than the other organics. Pecan shell, steam-activated and acid-activated GACs showed higher adsorption of 1,1,1-trichloroethane than the other carbons studied. Multivariate analysis was conducted to group experimental carbons and commercial carbons based on their physical, chemical, and adsorptive properties. The results of the analysis conclude that steam-activated and acid-activated pecan shell carbons clustered together with coal-based and coconut shell-based commercial carbons, thus inferring that these experimental carbons could potentially be used as alternative sources for VOC adsorption in an aqueous environment.

  7. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation

    International Nuclear Information System (INIS)

    Wei, Mingyu; Gao, Long; Li, Jun; Fang, Jia; Cai, Wenxuan; Li, Xiaoxia; Xu, Aihua

    2016-01-01

    Highlights: • Supported g-C_3N_4 on AC catalysts with different loadings were prepared. • The metal free catalysts exhibited high efficiency for dyes degradation with PMS. • The catalyst presented a long-term stability for multiple runs. • The C=O groups played a key role in the oxidation process. - Abstract: Graphitic carbon nitride supported on activated carbon (g-C_3N_4/AC) was prepared through an in situ thermal approach and used as a metal free catalyst for pollutants degradation in the presence of peroxymonosulfate (PMS) without light irradiation. It was found that g-C_3N_4 was highly dispersed on the surface of AC with the increase of surface area and the exposition of more edges and defects. The much easier oxidation of C species in g-C_3N_4 to C=O was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C_3N_4/AC catalyst within 20 min with PMS, while g-C_3N_4+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C_3N_4 loaded on AC; but was nearly not affected by the initial solution pH and reaction temperature. In addition, the catalysts presented good stability. A nonradical mechanism accompanied by radical generation (HO· and SO_4·"−) in AO7 oxidation was proposed in the system. The C=O groups play a key role in the process; while the exposure of more N-(C)_3 group can further increase its electron density and basicity. This study can contribute to the development of green materials for sustainable remediation of aqueous organic pollutants.

  8. Can Carbon Fluxes Explain Differences in Soil Organic Carbon Storage under Aspen and Conifer Forest Overstories?

    Directory of Open Access Journals (Sweden)

    Antra Boča

    2017-04-01

    Full Text Available Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC storage and stability. Quaking aspen (Populus tremuloides Michx. is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm, characterized stable and labile SOC pools, and quantified above- and belowground litter inputs and dissolved organic carbon (DOC fluxes during snowmelt in plots located in N and S Utah, to elucidate the role of foliage vs. root detritus in SOC storage and stabilization in both ecosystems. While leaf litterfall was twice as high under aspen as under conifers, input of litter-derived DOC with snowmelt water was consistently higher under conifers. Fine root (<2 mm biomass, estimated root detritus input, and root-derived DOC fluxes were also higher under conifers. A strong positive relationship between root and light fraction C content suggests that root detritus mostly fueled the labile fraction of SOC. Overall, neither differences in above- and belowground detritus C inputs nor in detritus-derived DOC fluxes could explain the higher and more stable SOC pools under aspen. We hypothesize that root–microbe–soil interactions in the rhizosphere are more likely to drive these SOC pool differences.

  9. P Status In Andisol And P Content In Arabica Coffee Seedling Leaves Due To The Application Of Phosphate Providing Microorganisms And Organic Matters In Bener Meriah District

    Directory of Open Access Journals (Sweden)

    Hifnalisa

    2017-09-01

    Full Text Available Bener Meriah district is one of the arabica coffee producing regions in Indonesia. Most of arabica coffee in Bener Meriah district grown on Andisol. Generally the availability of P in Andisol is very low. Phosphate providing microorganisms and organic matters can be used to increase Andisol P availability. The objective of this study was to examine the effect of the application of phosphate providing microorganisms and organic matters on P status in Andisol and P content in arabica coffee seedlings leaves in Bener Meriah district. The experiment used a randomized block design that consisted of two factors. Factor I was the application of phosphate providing microorganisms consisting of without microorganisms Glomus sp. Kurthia sp. Corynebacterium sp. and Listeria sp. Factor II was the application of organic matters consisting of T. diversifolia and coffee bean skins. The results of the study showed that Glomus sp. Kurthia sp. Corynebacterium sp. and Listeria sp. decreased soil P-retention by 2.38 5.12 7.48 9.17 respectively increased soil P-available by 24.85 36.03 52.79 77.33 respectively and increased P-content in the arabica coffee seedling leaves by 22.22 33.33 37.0372.27 respectively compared to without the application of microorganisms. The application of coffee bean skins resulted in lower soil P-retention higher soil P-available and P-content in arabica coffee seedling leaves than T. diversifolia. The application of Listeria sp.-coffee bean skins resulted in the lowest soil P-retention the highest soil P-available and P-content in arabica coffee seedlings leaves.

  10. Human induced impacts on soil organic carbon in southwest Iceland

    Science.gov (United States)

    Gísladóttir, Guðrún; Erlendsson, Egill; Lal, Rattan

    2013-04-01

    The Icelandic environment has been strongly influenced by natural processes during the Holocene. Since settlement in AD 874, the introduction of grazing animals and other land use has drastically affected the natural environment. This includes the diminishing of vegetative cover, which has led to soil exposure and accelerated erosion over large areas, especially when in conjunction with harsh climate. This has specifically impacted processes and properties of volcanic soils (Andosols), which are subject to accelerated erosion by wind and water. While approximately 46% of the land surface in Iceland has sustained continuous vegetation cover, large areas have lost some or all of their soil cover formed during the postglacial era. Elsewhere, remaining soils have sparse or no vegetation cover, thus impairing soil carbon (C) sequestration. Among their multifunctional roles, soils support plant growth, increase soil biotic activity, enhance nutrient storage and strengthen the cycling of water and nutrients. In contrast, soil degradation by accelerated erosion and other processes impairs soil quality, reduces soil structure and depletes the soil organic matter (SOM) pool. Depletion of the SOM pool has also global implications because the terrestrial C pool is the third largest pool and strongly impacts the global C cycle. Erosional-depositional processes may deplete soil organic C (SOC) by erosion and increase by deposition. Some SOC-enriched sediments are redistributed over the landscape, while others are deposited in depression sites and transported into aquatic ecosystems. SOC decomposition processes are severely constrained in some environmental settings and any SOC buried under anaerobic conditions is protected against decomposition. Yet, the impact of the SOC transported by erosional processes and redistributed over the landscape is not fully understood because the variability in its turnover characteristics has not been widely studied. Thus, the fate of C

  11. 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)

  12. Square-wave adsorptive stripping voltammetric determination of nanomolar levels of bezafibrate using a glassy carbon electrode modified with multi-walled carbon nanotubes within a dihexadecyl hydrogen phosphate film.

    Science.gov (United States)

    Ardila, Jorge Armando; Oliveira, Geiser Gabriel; Medeiros, Roberta Antigo; Fatibello-Filho, Orlando

    2014-04-07

    A highly sensitive method for bezafibrate determination using a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes within a dihexadecyl hydrogen phosphate film based on square-wave adsorptive stripping voltammetry (SWAdSV) is proposed. The electrochemical behaviour of bezafibrate has been studied by cyclic voltammetry, showing an irreversible anodic peak at a potential of 1.09 V in 0.1 mol L(-1) phosphate buffer solution (pH 2.0). A study of the scan rate showed that the oxidation of bezafibrate is an adsorptive-controlled process, involving the transfer of two electrons and two protons per molecule. The analytical curve was linear over a bezafibrate concentration range from 50 to 910 nmol L(-1), with a detection limit of 16 nmol L(-1). This analytical method was successfully applied for benzafibrate determination in pharmaceutical formulations, with results showing good agreement with those obtained using a comparative spectrophotometric method, and has the potential for field application.

  13. [Spatial characteristics of soil organic carbon and nitrogen storages in Songnen Plain maize belt].

    Science.gov (United States)

    Zhang, Chun-Hua; Wang, Zong-Ming; Ren, Chun-Ying; Song, Kai-Shan; Zhang, Bai; Liu, Dian-Wei

    2010-03-01

    By using the data of 382 typical soil profiles from the second soil survey at national and county levels, and in combining with 1:500000 digital soil maps, a spatial database of soil profiles was established. Based on this, the one meter depth soil organic carbon and nitrogen storage in Songnen Plain maize belt of China was estimated, with the spatial characteristics of the soil organic carbon and nitrogen densities as well as the relationships between the soil organic carbon and nitrogen densities and the soil types and land use types analyzed. The soil organic carbon and nitrogen storage in the maize belt was (163.12 +/- 26.48) Tg and (9.53 +/- 1.75) Tg, respectively, mainly concentrated in meadow soil, chernozem, and black soil. The soil organic carbon and nitrogen densities were 5.51-25.25 and 0.37-0.80 kg x m(-2), respectively, and the C/N ratio was about 7.90 -12.67. The eastern and northern parts of the belt had much higher carbon and nitrogen densities than the other parts of the belt, and upland soils had the highest organic carbon density [(19.07 +/- 2.44) kg x m(-2)], forest soils had the highest nitrogen density [(0.82 +/- 0.25) kg x m(-2)], while lowland soils had the lower organic carbon and nitrogen densities.

  14. Dissolved organic carbon pools and export from the coastal ocean

    KAUST Repository

    Barrón, Cristina

    2015-10-21

    The distribution of dissolved organic carbon (DOC) concentration across coastal waters was characterized based on the compilation of 3510 individual estimates of DOC in coastal waters worldwide. We estimated the DOC concentration in the coastal waters that directly exchange with open ocean waters in two different ways, as the DOC concentration at the edge of the shelf break and as the DOC concentration in coastal waters with salinity close to the average salinity in the open ocean. Using these estimates of DOC concentration in the coastal waters that directly exchange with open ocean waters, the mean DOC concentration in the open ocean and the estimated volume of water annually exchanged between coastal and open ocean, we estimated a median ± SE (and average ± SE) global DOC export from coastal to open ocean waters ranging from 4.4 ± 1.0 Pg C yr−1 to 27.0 ± 1.8 Pg C yr−1 (7.0 ± 5.8 Pg C yr−1 to 29.0 ± 8.0 Pg C yr−1) depending on the global hydrological exchange. These values correspond to a median and mean median (and average) range between 14.7 ± 3.3 to 90.0 ± 6.0 (23.3 ± 19.3 to 96.7 ± 26.7) Gg C yr−1 per km of shelf break, which is consistent with the range between 1.4 to 66.1 Gg C yr−1 per km of shelf break of available regional estimates of DOC export. The estimated global DOC export from coastal to open ocean waters is also consistent with independent estimates of the net metabolic balance of the coastal ocean. The DOC export from the coastal to the open ocean is likely to be a sizeable flux and is likely to be an important term in the carbon budget of the open ocean, potentially providing an important subsidy to support heterotrophic activity in the open ocean.

  15. Dissolved organic carbon pools and export from the coastal ocean

    KAUST Repository

    Barró n, Cristina; Duarte, Carlos M.

    2015-01-01

    The distribution of dissolved organic carbon (DOC) concentration across coastal waters was characterized based on the compilation of 3510 individual estimates of DOC in coastal waters worldwide. We estimated the DOC concentration in the coastal waters that directly exchange with open ocean waters in two different ways, as the DOC concentration at the edge of the shelf break and as the DOC concentration in coastal waters with salinity close to the average salinity in the open ocean. Using these estimates of DOC concentration in the coastal waters that directly exchange with open ocean waters, the mean DOC concentration in the open ocean and the estimated volume of water annually exchanged between coastal and open ocean, we estimated a median ± SE (and average ± SE) global DOC export from coastal to open ocean waters ranging from 4.4 ± 1.0 Pg C yr−1 to 27.0 ± 1.8 Pg C yr−1 (7.0 ± 5.8 Pg C yr−1 to 29.0 ± 8.0 Pg C yr−1) depending on the global hydrological exchange. These values correspond to a median and mean median (and average) range between 14.7 ± 3.3 to 90.0 ± 6.0 (23.3 ± 19.3 to 96.7 ± 26.7) Gg C yr−1 per km of shelf break, which is consistent with the range between 1.4 to 66.1 Gg C yr−1 per km of shelf break of available regional estimates of DOC export. The estimated global DOC export from coastal to open ocean waters is also consistent with independent estimates of the net metabolic balance of the coastal ocean. The DOC export from the coastal to the open ocean is likely to be a sizeable flux and is likely to be an important term in the carbon budget of the open ocean, potentially providing an important subsidy to support heterotrophic activity in the open ocean.

  16. Distribution of organic carbon and petroleum source rock potential of Cretaceous and lower Tertiary carbonates, South Florida Basin: preliminary results

    Science.gov (United States)

    Palacas, James George

    1978-01-01

    Analyses of 134 core samples from the South Florida Basin show that the carbonates of Comanchean age are relatively richer in average organic carbon (0.41 percent) than those of Coahuilan age (0.28 percent), Gulfian age (0.18 percent) and Paleocene age (0.20 percent). They are also nearly twice as rich as the average world, wide carbonate (average 0.24 percent). The majority of carbonates have organic carbons less than 0.30 percent but the presence of many relatively organic rich beds composed of highly bituminous, argillaceous, highly stylolitic, and algal-bearing limestones and dolomites accounts for the higher percentage of organic carbon in some of the stratigraphic units. Carbonate rocks that contain greater than 0.4 percent organic carbon and that might be considered as possible petroleum sources were noted in almost each subdivision of the Coahuilan and Comanchean Series but particularly the units of Fredericksburg 'B', Trinity 'A', Trinity 'F', and Upper Sunniland. Possible source rocks have been ascribed by others to the Lower Sunniland, but lack of sufficient samples precluded any firm assessment in this initial report. In the shallower section of the basin, organic-rich carbonates containing as much as 3.2 percent organic carbon were observed in the lowermost part of the Gulfian Series and carbonate rocks with oil staining or 'dead' and 'live oil' were noted by others in the uppermost Gulfian and upper Cedar Keys Formation. It is questionable whether these shallower rocks are of sufficient thermal maturity to have generated commercial oil. The South Florida basin is still sparsely drilled and produces only from the Sunniland Limestone at an average depth of 11,500 feet (3500 m). Because the Sunniland contains good reservoir rocks and apparently adequate source rocks, and because the success rate of new oil field discoveries has increased in recent years, the chances of finding additional oil reserves in the Sunniland are promising. Furthermore, the

  17. Economics- and policy-driven organic carbon input enhancement dominates soil organic carbon accumulation in Chinese croplands.

    Science.gov (United States)

    Zhao, Yongcun; Wang, Meiyan; Hu, Shuijin; Zhang, Xudong; Ouyang, Zhu; Zhang, Ganlin; Huang, Biao; Zhao, Shiwei; Wu, Jinshui; Xie, Deti; Zhu, Bo; Yu, Dongsheng; Pan, Xianzhang; Xu, Shengxiang; Shi, Xuezheng

    2018-04-17

    China's croplands have experienced drastic changes in management practices, such as fertilization, tillage, and residue treatments, since the 1980s. There is an ongoing debate about the impact of these changes on soil organic carbon (SOC) and its implications. Here we report results from an extensive study that provided direct evidence of cropland SOC sequestration in China. Based on the soil sampling locations recorded by the Second National Soil Survey of China in 1980, we collected 4,060 soil samples in 2011 from 58 counties that represent the typical cropping systems across China. Our results showed that across the country, the average SOC stock in the topsoil (0-20 cm) increased from 28.6 Mg C ha -1 in 1980 to 32.9 Mg C ha -1 in 2011, representing a net increase of 140 kg C ha -1 year -1 However, the SOC change differed among the major agricultural regions: SOC increased in all major agronomic regions except in Northeast China. The SOC sequestration was largely attributed to increased organic inputs driven by economics and policy: while higher root biomass resulting from enhanced crop productivity by chemical fertilizers predominated before 2000, higher residue inputs following the large-scale implementation of crop straw/stover return policy took over thereafter. The SOC change was negatively related to N inputs in East China, suggesting that the excessive N inputs, plus the shallowness of plow layers, may constrain the future C sequestration in Chinese croplands. Our results indicate that cropland SOC sequestration can be achieved through effectively manipulating economic and policy incentives to farmers.

  18. Testing the ``Wildfire Hypothesis:'' Terrestrial Organic Carbon Burning as the Cause of the Paleocene-Eocene Boundary Carbon Isotope Excursion

    Science.gov (United States)

    Moore, E. A.; Kurtz, A. C.

    2005-12-01

    The 3‰ negative carbon isotope excursion (CIE) at the Paleocene-Eocene boundary has generally been attributed to dissociation of seafloor methane hydrates. We are testing the alternative hypothesis that the carbon cycle perturbation resulted from wildfires affecting the extensive peatlands and coal swamps formed in the Paleocene. Accounting for the CIE with terrestrial organic carbon rather than methane requires a significantly larger net release of fossil carbon to the ocean-atmosphere, which may be more consistent with the extreme global warming and ocean acidification characteristic of the Paleocene-Eocene Thermal Maximum (PETM). While other researchers have noted evidence of fires at the Paleocene-Eocene boundary in individual locations, the research presented here is designed to test the "wildfire hypothesis" for the Paleocene-Eocene boundary by examining marine sediments for evidence of a global increase in wildfire activity. Such fires would produce massive amounts of soot, widely distributed by wind and well preserved in marine sediments as refractory black carbon. We expect that global wildfires occurring at the Paleocene-Eocene boundary would produce a peak in black carbon abundance at the PETM horizon. We are using the method of Gelinas et al. (2001) to produce high-resolution concentration profiles of black carbon across the Paleocene-Eocene boundary using seafloor sediments from ODP cores, beginning with the Bass River core from ODP leg 174AX and site 1209 from ODP leg 198. This method involves the chemical and thermal extraction of non-refractory carbon followed by combustion of the residual black carbon and measurement as CO2. Measurement of the δ 13C of the black carbon will put additional constraints on the source of the organic material combusted, and will allow us to determine if this organic material was formed prior to or during the CIE.

  19. Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Massachusetts Institute of Technology; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R.; Wilson, Kevin R.; Altieri, Katye E.; Mazzoleni, Lynn R.; Wozniak, Andrew S.; Bluhm, Hendrik; Mysak, Erin R.; Smith, Jared D.; Kolb, Charles E.; Worsnop, Douglas R.

    2010-11-05

    A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).

  20. Carbon trading as incentive for conversion to organic agriculture. Case study. Organic peanuts in Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Bodnar, F.

    2005-12-15

    In this pilot project, the climate effects of the conversion from conventional to organic cultivation of peanuts are evaluated. We could aim at voluntary carbon credits that do not comply with the CDM (Clean Development Mechanisms) rules, but we try to meet the CDM rules by combining it with a agroforestry component. However, in the example of Tanzania meeting the CDM rules was a problem. The agricultural system in Tanzania consists of a rotation of several years cultivation and several years fallow. This fallow of grass, shrubs and trees could be considered as 'forest'. Taking fallow land into cultivation would then be deforestation, which would make the planting of trees no longer eligible under CDM. This is a shame because the traditional 'slash and burn' system emits a lot of greenhouse gases.

  1. Humin to Human: Organic carbon, sediment, and water fluxes along river corridors in a changing world

    Energy Technology Data Exchange (ETDEWEB)

    Sutfin, Nicholas Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-20

    This is a presentation with slides on What does it mean to be human? ...humin?; River flow and Hydrographs; Snake River altered hydrograph (Marston et al., 2005); Carbon dynamics are important in rivers; Rivers and streams as carbon sink; Reservoirs for organic carbon; Study sites in Colorado; River morphology; Soil sample collection; Surveys at RMNP; Soil organic carbon content at RMNP; Abandoned channels and Cutoffs; East River channel migration and erosion; Linking hydrology to floodplain sediment flux; Impact of Extreme Floods on Floodplain Sediment; Channel Geometry: RMNP; Beavers dams and multithread channels; Geomorphology and carbon in N. St. Vrain Creek; Geomorphology and carbon along the East River; Geomorphology and carbon in N. St. Vrain Creek; San Marcos River, etc.

  2. Organic carbon exportation in a tobacco cropped watershed

    Science.gov (United States)

    de Mello, N.; Merten, G.; Pontarolo, E.

    2009-04-01

    The agricultural land use is indispensable for survival of the humankind; but inadequate agricultural use may disturb or modify steady states generating environmental damage. The amount of organic carbon (OC) in the soil is a result of the balance between addition by primary production and carbon losses, mainly by the oxidation and mineralization by microorganisms activity and depletion by erosion process. The losses will ultimately reduce the primary production, affecting the additions and undermining the soil quality, moving it away from the sustainability. Areas under tobacco (Nicotiana tabacum L.) cropping are generally potential for environmental contamination, because they are based on intensive agricultural operations, with low OC addition, due the removal of almost the totality of the biomass of the main crop. In tobacco, the leaves are the part of commercial interest. This removal, associated with the conventional management of soils makes difficult to preserve the soil OC budget which ends up being rapidly degraded. However, the soil management system also can raise the soil OC content, if not to the original levels, as in the areas under native vegetation, at least, in adequate levels to ensure the soil quality. The organic carbon of an agricultural area may be exported associated to sediments in the fraction associated with minerals (CAM) as in the particulate fraction (POC), or in dissolved form (DOC), however the processes of losses and translocation occurs in distinct ways, as a function of different factors, as soil type, slope length, soil management and climate. The results may also be changed when different scale of observation is adopted. This work was carried out in a rural watershed, cropped with tobacco mainly under conventional management system. Tobacco is still a crop of economic importance in developing countries, such as Brazil. The study was conducted during four years in small plots, hillslopes and catchment scale. In the small plots

  3. Dissolved organic carbon in the INDEX area of the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; De

    -Sea Research II 48 (2001) 3353–3361 Dissolved organic carbon in the INDEX area of the Central Indian Basin Sugandha Sardessai*, S.N. de Sousa National Institute of Oceanography, Dona-Paula, Goa 403 004, India Abstract Dissolved organic carbon (DOC..., 1996). While there is substantial information available on the DOC content of sea water throughout the Atlantic, Pacific and southern oceans, there are limited reports on contents and distribution of this organic fraction in the Indian Ocean (Menzel...

  4. Sm-Nd in marine carbonates and phosphates: implications for Nd isotopes in seawater and crustal ages

    International Nuclear Information System (INIS)

    Shaw, H.F.; Wasserburg, G.J.

    1985-01-01

    This study explores the possibility of establishing Nd isotopic variations in seawater over geologic time. Calcite, aragonite and apatite are examined as possible phases recording seawater values of epsilonsubNd. Modern, biogenic and inorganically precipitated calcite and aragonite from marine environments were found to have Nd concentrations of from 0.2 to 70 ppb, showing that primary marine CaCO 3 contains little REE and that Nd/Ca is not greatly enhanced relative to seawater during carbonate precipitation. Very young marine limestone and dolomite containing no continental detritus have approx. 200 ppb Nd. All the carbonates are LREE enriched. Modern and very young Atlantic and Pacific carbonates have epsilonsub(Nd) in the range of shallow Atlantic and Pacific seawater respectively, implying that they derive their REE from local seawater. The Nd in well preserved carbonate fossils is 4 ppb, much greater than in their modern counterparts but like the high values found for carbonates in other studies. Results are also reported for apatite. They suggest that sedimentary apatite can be used to determine epsilonsub(Nd)(T) in ancient seawater. The seawater values so inferred range between -1.7 and -8.9 over the last 700 my and lie in the range of modern seawater, showing no evidence for drastic changes. (U.K.)

  5. Dissolved organic carbon enhances the mass transfer of hydrophobic organic compounds from Nonaqueous Phase Liquids (NAPLs) into the aqueous phase

    NARCIS (Netherlands)

    Smith, K.E.C.; Thullner, M.; Wick, L.Y.; Harms, H.

    2011-01-01

    The hypothesis that dissolved organic carbon (DOC) enhances the mass transfer of hydrophobic organic compounds from nonaqueous phase liquids (NAPLs) into the aqueous phase above that attributable to dissolved molecular diffusion alone was tested. In controlled experiments, mass transfer rates of

  6. Biogeochemical stability and reactions of iron-organic carbon complexes

    Science.gov (United States)

    Yang, Y.; Adhikari, D.; Zhao, Q.; Dunham-Cheatham, S.; Das, K.; Mejia, J.; Huang, R.; Wang, X.; Poulson, S.; Tang, Y.; Obrist, D.; Roden, E. E.

    2017-12-01

    Our core hypothesis is that the degradation rate of soil organic carbon (OC) is governed by the amount of iron (Fe)-bound OC, and the ability of microbial communities to utilize OC as an energy source and electron shuttle for Fe reduction that in turn stimulates reductive release of Fe-bound labile dissolved OC. This hypothesis is being systematically evaluated using model Fe-OC complexes, natural soils, and microcosm system. We found that hematite-bound aliphatic C was more resistant to reduction release, although hematite preferred to sorb more aromatic C. Resistance to reductive release represents a new mechanism that aliphatic soil OC was stabilized by association with Fe oxide. In other studies, pyrogenic OC was found to facilitate the reduction of hematite, by enhancing extracellular electron transport and sorbing Fe(II). For ferrihydrite-OC co-precipitates, the reduction of Fe and release of OC was closely governed by the C/Fe ratio in the system. Based on the XPS, XANES and XAFS analysis, the transformation of Fe speciation was heterogeneous, depending on the conformation and composition of Fe-OC complexes. For natural soils, we investigated the quantity, characteristics, and reactivity of Fe-bound OC in soils collected from 14 forests in the United States. Fe-bound OC contributed up to 57.8% of total OC in the forest soils. Under the anaerobic conditions, the reduction of Fe was positively correlated to the electron accepting capacity of OC. Our findings highlight the closely coupled dynamics of Fe and OC, with broad implications on the turnover of OC and biogeochemical cycles of Fe.

  7. Organic carbon burial in fjords: Terrestrial versus marine inputs

    Science.gov (United States)

    Cui, Xingqian; Bianchi, Thomas S.; Savage, Candida; Smith, Richard W.

    2016-10-01

    Fjords have been identified as sites of enhanced organic carbon (OC) burial and may play an important role in regulating climate change on glacial-interglacial timescales. Understanding sediment processes and sources of sedimentary OC are necessary to better constrain OC burial in fjords. In this study, we use Fiordland, New Zealand, as a case study and present data on surface sediments, sediment down-cores and terrestrial end-members to examine dynamics of sediments and the sources of OC in fjord sediments. Sediment cores showed evidence of multiple particle sources, frequent bioturbation and mass-wasting events. A multi-proxy approach (stable isotopes, lignin-phenols and fatty acids) allowed for separation of marine, soil and vascular plant OC in surface sediments. The relationship between mass accumulation rate (MAR) and OC contents in fjord surface sediments suggested that mineral dilution is important in controlling OC content on a global scale, but is less important for specific regions (e.g., New Zealand). The inconsistency of OC budgets calculated by using MAR weighted %OC and OC accumulation rates (AR; 6 vs 21-31 Tg OC yr-1) suggested that sediment flux in fjords was likely underestimated. By using end-member models, we propose that 55% to 62% of total OC buried in fjords is terrestrially derived, and accounts for 17 ± 12% of the OCterr buried in all marine sediments. The strong correlation between MAR and OC AR indicated that OC flux will likely decrease in fjords in the future with global warming due to decrease in sediment flux caused by glacier denudation.

  8. Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

    Science.gov (United States)

    Geer, Tyler D; Kinley, Ciera M; Iwinski, Kyla J; Calomeni, Alyssa J; Rodgers, John H

    2016-10-01

    Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the

  9. Phosphate Salts

    Science.gov (United States)

    ... body. They are involved in cell structure, energy transport and storage, vitamin function, and numerous other processes ... Phosphate-containing foods and beverages include cola, wine, beer, whole grain cereals, nuts, dairy products and some ...

  10. Deposition and Burial Efficiency of Terrestrial Organic Carbon Exported from Small Mountainous Rivers to the Continental Margin, Southwest of Taiwan

    Science.gov (United States)

    Hsu, F.; Lin, S.; Wang, C.; Huh, C.

    2007-12-01

    Terrestrial organic carbon exported from small mountainous river to the continental margin may play an important role in global carbon cycle and it?|s biogeochemical process. A huge amount of suspended materials from small rivers in southwestern Taiwan (104 million tons per year) could serve as major carbon source to the adjacent ocean. However, little is know concerning fate of this terrigenous organic carbon. The purpose of this study is to calculate flux of terrigenous organic carbon deposited in the continental margin, offshore southwestern Taiwan through investigating spatial variation of organic carbon content, organic carbon isotopic compositions, organic carbon deposition rate and burial efficiency. Results show that organic carbon compositions in sediment are strongly influenced by terrestrial material exported from small rivers in the region, Kaoping River, Tseng-wen River and Er-jan Rver. In addition, a major part of the terrestrial materials exported from the Kaoping River may bypass shelf region and transport directly into the deep sea (South China Sea) through the Kaoping Canyon. Organic carbon isotopic compositions with lighter carbon isotopic values are found near the Kaoping River and Tseng-wen River mouth and rapidly change from heavier to lighter values through shelf to slope. Patches of lighter organic carbon isotopic compositions with high organic carbon content are also found in areas west of Kaoping River mouth, near the Kaoshiung city. Furthermore, terrigenous organic carbons with lighter isotopic values are found in the Kaoping canyon. A total of 0.028 Mt/yr of terrestrial organic carbon was found in the study area, which represented only about 10 percent of all terrestrial organic carbon deposited in the study area. Majority (~90 percent) of the organic carbon exported from the Kaoping River maybe directly transported into the deep sea (South China Sea) and become a major source of organic carbon in the deep sea.

  11. Method of stripping plutonium from tributyl phosphate solution which contains dibutyl phosphate-plutonium stable complexes

    International Nuclear Information System (INIS)

    Ochsenfeld, W.; Schmieder, H.

    1976-01-01

    Fast breeder fuel elements which have been highly burnt-up are reprocessed by extracting uranium and plutonium into an organic solution containing tributyl phosphate. The tributyl phosphate degenerates at least partially into dibutyl phosphate and monobutyl phosphate, which form stable complexes with tetravalent plutonium in the organic solution. This tetravalent plutonium is released from its complexed state and stripped into aqueous phase by contacting the organic solution with an aqueous phase containing tetravalent uranium. 6 claims, 1 drawing figure

  12. Uranium Removal from Groundwater by Permeable Reactive Barrier with Zero-Valent Iron and Organic Carbon Mixtures: Laboratory and Field Studies

    Directory of Open Access Journals (Sweden)

    Borys Kornilovych

    2018-06-01

    Full Text Available Zhovty Vody city, located in south-central Ukraine, has long been an important center for the Ukrainian uranium and iron industries. Uranium and iron mining and processing activities during the Cold War resulted in poorly managed sources of radionuclides and heavy metals. Widespread groundwater and surface water contamination has occurred, which creates a significant risk to drinking water supplies. Hydrogeologic and geochemical conditions near large uranium mine tailings storage facility (TSF were characterized to provide data to locate, design and install a permeable reactive barrier (PRB to treat groundwater contaminated by leachate infiltrating from the TSF. The effectiveness of three different permeable reactive materials was investigated: zero-valent iron (ZVI for reduction, sorption, and precipitation of redox-sensitive oxyanions; phosphate material to transform dissolved metals to less soluble phases; and organic carbon substrates to promote bioremediation processes. Batch and column experiments with Zhovty Vody site groundwater were conducted to evaluate reactivity of the materials. Reaction rates, residence time and comparison with site-specific clean-up standards were determined. Results of the study demonstrate the effectiveness of the use of the PRB for ground water protection near uranium mine TSF. The greatest decrease was obtained using ZVI-based reactive media and the combined media of ZVI/phosphate/organic carbon combinations.

  13. Role of organic soils in the world carbon cycle: problem definition and research needs

    Energy Technology Data Exchange (ETDEWEB)

    Armentano, T.V. (ed.)

    1979-01-01

    Findings and recommendations of the workshop on organic soils are summarized. The major finding of the workshop is that organic soils are important in the overall carbon budget. Histosols and gleysols, the major organic soil deposits of the world, normally sequester organic carbon fixed by plants. They may now be releasing enough carbon to account for nearly 10% of the annual rise in atmospheric content of CO/sub 2/. Current annual release of carbon from organic soils is estimated to fall within the range of 0.03 to 0.37 x 10/sup 9/ t, a release equivalent to 1.3% to 16% of the annual increase of carbon in the atmosphere. If half of the released carbon remains airborne, organic soils contribute 0.6% to 8.0% of the annual rise in CO/sub 2/. Uncertainties in data suggest the actual release could lie outside the range. Present annual releases of carbon from the Everglades Agricultural Area in Florida and the Sacramento-San Joaquin Valley in California are estimated at 0.017 x 10/sup 9/ tons. When combined with additional carbon release from other known drainage programs and the possibility of major drainage activity in the tropics, this figure suggests that the lower limit of the world estimate of carbon release from organic soils is too low. Annual sequestering of carbon by undrained organic soils has been estimated at about 0.045 x 10/sup 9/ tons. This estimate is based on only a few studies, however, and precision is probably no better than an order of magnitude. Several strategies for peatland management are available, including creation, preservation, functional designation, and use of wetlands for agriculture and energy supply.

  14. High resolution of black carbon and organic carbon emissions in the Pearl River Delta region, China.

    Science.gov (United States)

    Zheng, Junyu; He, Min; Shen, Xingling; Yin, Shasha; Yuan, Zibing

    2012-11-01

    A high-resolution regional black carbon (BC) and organic carbon (OC) emission inventory for the year 2009 was developed for the Pearl River Delta (PRD) region, China, based on the collected activity data and the latest emission factors. PM(2.5), BC and OC emissions were estimated to be 303 kt, 39 kt and 31 kt, respectively. Industrial processes were major contributing sources to PM(2.5) emissions. BC emissions were mainly from mobile sources, accounting for 65.0%, while 34.1% of OC emissions were from residential combustion. The primary OC/BC ratios for individual cities in the PRD region were dependent on the levels of economic development due to differences in source characteristics, with high ratios in the less developed cities and low ratios in the central and southern developed areas. The preliminary temporal profiles were established, showing the highest OC emissions in winter and relatively constant BC emissions throughout the year. The emissions were spatially allocated into grid cells with a resolution of 3 km × 3 km. Large amounts of BC emissions were distributed over the central-southern PRD city clusters, while OC emissions exhibited a relatively even spatial distribution due to the significant biomass burning emissions from the outlying area of the PRD region. Uncertainties in carbonaceous aerosol emissions were usually higher than in other primary pollutants like SO(2), NO(x), and PM(10). One of the key uncertainty sources was the emission factor, due to the absence of direct measurements of BC and OC emission rates. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Carbon sequestration potential of soils in southeast Germany derived from stable soil organic carbon saturation.

    Science.gov (United States)

    Wiesmeier, Martin; Hübner, Rico; Spörlein, Peter; Geuß, Uwe; Hangen, Edzard; Reischl, Arthur; Schilling, Bernd; von Lützow, Margit; Kögel-Knabner, Ingrid

    2014-02-01

    Sequestration of atmospheric carbon (C) in soils through improved management of forest and agricultural land is considered to have high potential for global CO2 mitigation. However, the potential of soils to sequester soil organic carbon (SOC) in a stable form, which is limited by the stabilization of SOC against microbial mineralization, is largely unknown. In this study, we estimated the C sequestration potential of soils in southeast Germany by calculating the potential SOC saturation of silt and clay particles according to Hassink [Plant and Soil 191 (1997) 77] on the basis of 516 soil profiles. The determination of the current SOC content of silt and clay fractions for major soil units and land uses allowed an estimation of the C saturation deficit corresponding to the long-term C sequestration potential. The results showed that cropland soils have a low level of C saturation of around 50% and could store considerable amounts of additional SOC. A relatively high C sequestration potential was also determined for grassland soils. In contrast, forest soils had a low C sequestration potential as they were almost C saturated. A high proportion of sites with a high degree of apparent oversaturation revealed that in acidic, coarse-textured soils the relation to silt and clay is not suitable to estimate the stable C saturation. A strong correlation of the C saturation deficit with temperature and precipitation allowed a spatial estimation of the C sequestration potential for Bavaria. In total, about 395 Mt CO2 -equivalents could theoretically be stored in A horizons of cultivated soils - four times the annual emission of greenhouse gases in Bavaria. Although achieving the entire estimated C storage capacity is unrealistic, improved management of cultivated land could contribute significantly to CO2 mitigation. Moreover, increasing SOC stocks have additional benefits with respect to enhanced soil fertility and agricultural productivity. © 2013 John Wiley & Sons Ltd.

  16. Production of carbon-14 and preparation of some key precursors for labeling organic molecules

    International Nuclear Information System (INIS)

    Moriya, T.; Motoishi, S.

    1992-01-01

    Production of carbon-14 on 50 GBq scale has been performed by neutron irradiation of aluminium nitride target in the JMTR. This nuclide is separated in carbon dioxide form by combustion of the irradiated target at 1100degC with oxygen. The [ 14 C] carbon dioxide liberated thus is trapped in caustic solution and finally recovered as [ 14 C] barium carbonate. Some precursors useful for incorporating carbon-14 into a given organic molecule have been prepared. Precursors such as [1- 14 C] sodium acetate, [ 14 C] methanol and [ 14 C] potassium cyanide are prepared by rather conventional methods involving carbonation of methyl magnesium iodine, reduction of carbon dioxide with lithium aluminium hydride and reduction of carbonate with metallic potassium in the presence of ammonium salt, respectively. A catalytic polymerization of acetylene is used to prepare benzene. (author)

  17. Influence of natural and novel organic carbon sources on denitrification in forest, degraded urban, and restored streams

    Science.gov (United States)

    Organic carbon is important in regulating ecosystem function, and its source and abundance may be altered by urbanization. We investigated shifts in organic carbon quantity and quality associated with urbanization and ecosystem restoration, and its potential effects on denitrific...

  18. Histological Evaluation of Degradable Guided Bone Regeneration Membranes Prepared from Poly(trimethylene carbonate) and Biphasic Calcium Phosphate Composites

    NARCIS (Netherlands)

    Zeng, Ni; van Leeuwen, Anne; Bos, Ruud R.M.; Grijpma, Dirk W.; Kuijer, Roel

    2013-01-01

    In oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as

  19. Histological evaluation of degradable guided bone regeneration membranes prepared from poly(trimethylene carbonate) and biphasic calcium phosphate composites

    NARCIS (Netherlands)

    Zeng, Ni; van Leeuwen, Anne; Bos, Ruud R.M.; Grijpma, Dirk W.; Kuijer, Roel

    2013-01-01

    In oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as

  20. Metal-Organic-Framework-Mediated Nitrogen-Doped Carbon for CO2 Electrochemical Reduction

    KAUST Repository

    Wang, Riming; Sun, Xiaohui; Ould-Chikh, Samy; Osadchii, Dmitrii; Bai, Fan; Kapteijn, Freek; Gascon, Jorge

    2018-01-01

    A nitrogen-doped carbon was synthesized through the pyrolysis of the well-known metal-organic framework ZIF-8, followed by a subsequent acid treatment, and has been applied as a catalyst in the electrochemical reduction of carbon dioxide. The resulting electrode shows Faradaic efficiencies to carbon monoxide as high as ∼78%, with hydrogen being the only byproduct. The pyrolysis temperature determines the amount and the accessibility of N species in the carbon electrode, in which pyridinic-N and quaternary-N species play key roles in the selective formation of carbon monoxide.

  1. Metal-Organic-Framework-Mediated Nitrogen-Doped Carbon for CO2 Electrochemical Reduction

    KAUST Repository

    Wang, Riming

    2018-04-11

    A nitrogen-doped carbon was synthesized through the pyrolysis of the well-known metal-organic framework ZIF-8, followed by a subsequent acid treatment, and has been applied as a catalyst in the electrochemical reduction of carbon dioxide. The resulting electrode shows Faradaic efficiencies to carbon monoxide as high as ∼78%, with hydrogen being the only byproduct. The pyrolysis temperature determines the amount and the accessibility of N species in the carbon electrode, in which pyridinic-N and quaternary-N species play key roles in the selective formation of carbon monoxide.

  2. RECIPROCAL RELATIONSHIPS BETWEEN AGGREGATE STABILITY AND ORGANIC CARBON CHARACTERISTICS IN A FORESTED ECOSYSTEM OF NORTHERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Halima Mohammed Lawal

    2012-10-01

    Full Text Available Soil organic matter associated with different size aggregates differ in structure and function; therefore, play different roles in soil organic carbon (SOC turnover. This study assessed the relationship between aggregate stability and soil organic carbon fractions in a forested soil. Aggregate stability characterized by mean weight diameter (MWD was correlated with the various pools of SOC in a regression model. Mean weight diameter presented a 46% influence on total organic carbon (TOC while, TOC accounts for 21.8% 0f aggregate stability. The unprotected and physically protected soil organic carbon did not significantly dictate stability of these soils. However, chemically protected and biochemically protected SOC influenced significantly aggregate stability of these forested soils.

  3. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

    Science.gov (United States)

    Cao, Qingqing; Wang, Renqing; Zhang, Haijie; Ge, Xiuli; Liu, Jian

    2015-01-01

    Wetland ecosystems are represented as a significant reservoir of organic carbon and play an important role in mitigating the greenhouse effect. In order to compare the compositions and distribution of organic carbon in constructed and natural river wetlands, sediments from the Xinxue River Constructed Wetland and the Xinxue River, China, were sampled at two depths (0-15 cm and 15-25 cm) in both upstream and downstream locations. Three types of organic carbon were determined: light fraction organic carbon, heavy fraction organic carbon, and dissolved organic carbon. The results show that variations in light fraction organic carbon are significantly larger between upstream and downstream locations than they are between the two wetland types; however, the opposite trend is observed for the dissolved organic carbon. There are no significant differences in the distribution of heavy fraction organic carbon between the discrete variables (e.g., between the two depths, the two locations, or the two wetland types). However, there are significant cross-variable differences; for example, the distribution patterns of heavy fraction organic carbon between wetland types and depths, and between wetland types and locations. Correlation analysis reveals that light fraction organic carbon is positively associated with light fraction nitrogen in both wetlands, while heavy fraction organic carbon is associated with both heavy fraction nitrogen and the moisture content in the constructed wetland. The results of this study demonstrate that the constructed wetland, which has a relatively low background value of heavy fraction organic carbon, is gradually accumulating organic carbon of different types, with the level of accumulation dependent on the balance between carbon accumulation and carbon decomposition. In contrast, the river wetland has relatively stable levels of organic carbon.

  4. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Mingyu; Gao, Long; Li, Jun [School of Environmental Engineering, Wuhan Textile University, Wuhan 430073 (China); Fang, Jia [School of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430073 (China); Cai, Wenxuan [School of Environmental Engineering, Wuhan Textile University, Wuhan 430073 (China); Li, Xiaoxia [School of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan 430073 (China); Xu, Aihua, E-mail: xahspinel@sina.com [School of Environmental Engineering, Wuhan Textile University, Wuhan 430073 (China); Engineering Research Center for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan 430073 (China)

    2016-10-05

    Highlights: • Supported g-C{sub 3}N{sub 4} on AC catalysts with different loadings were prepared. • The metal free catalysts exhibited high efficiency for dyes degradation with PMS. • The catalyst presented a long-term stability for multiple runs. • The C=O groups played a key role in the oxidation process. - Abstract: Graphitic carbon nitride supported on activated carbon (g-C{sub 3}N{sub 4}/AC) was prepared through an in situ thermal approach and used as a metal free catalyst for pollutants degradation in the presence of peroxymonosulfate (PMS) without light irradiation. It was found that g-C{sub 3}N{sub 4} was highly dispersed on the surface of AC with the increase of surface area and the exposition of more edges and defects. The much easier oxidation of C species in g-C{sub 3}N{sub 4} to C=O was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C{sub 3}N{sub 4}/AC catalyst within 20 min with PMS, while g-C{sub 3}N{sub 4}+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C{sub 3}N{sub 4} loaded on AC; but was nearly not affected by the initial solution pH and reaction temperature. In addition, the catalysts presented good stability. A nonradical mechanism accompanied by radical generation (HO· and SO{sub 4}·{sup −}) in AO7 oxidation was proposed in the system. The C=O groups play a key role in the process; while the exposure of more N-(C){sub 3} group can further increase its electron density and basicity. This study can contribute to the development of green materials for sustainable remediation of aqueous organic pollutants.

  5. Elemental and organic carbon in aerosols over urbanized coastal region (southern Baltic Sea, Gdynia).

    Science.gov (United States)

    Lewandowska, Anita; Falkowska, Lucyna; Murawiec, Dominika; Pryputniewicz, Dorota; Burska, Dorota; Bełdowska, Magdalena

    2010-09-15

    Studies on PM 10, total particulate matter (TSP), elemental carbon (EC) and organic carbon (OC) concentrations were carried out in the Polish coastal zone of the Baltic Sea, in urbanized Gdynia. The interaction between the land, the air and the sea was clearly observed. The highest concentrations of PM 10, TSP and both carbon fractions were noted in the air masses moving from southern and western Poland and Europe. The EC was generally of primary origin and its contribution to TSP and PM 10 mass was on average 2.3% and 3.7% respectively. Under low wind speed conditions local sources (traffic and industry) influenced increases in elemental carbon and PM 10 concentrations in Gdynia. Elemental carbon demonstrated a pronounced weekly cycle, yielding minimum values at the weekend and maximum values on Thursdays. The role of harbors and ship yards in creating high EC concentrations was clearly observed. Concentration of organic carbon was ten times higher than that of elemental carbon, and the average OC contribution to PM 10 mass was very high (31.6%). An inverse situation was observed when air masses were transported from over the Atlantic Ocean, the North Sea and the Baltic Sea. These clean air masses were characterized by the lowest concentrations of all analysed compounds. Obtained results for organic and elemental carbon fluxes showed that atmospheric aerosols can be treated, along with water run-off, as a carbon source for the coastal waters of the Baltic Sea. The enrichment of surface water was more effective in the case of organic carbon (0.27+/-0.19 mmol m(-2) d(-1)). Elemental carbon fluxes were one order of magnitude smaller, on average 0.03+/-0.04 mmol m(-2) d(-1). We suggest that in some situations atmospheric carbon input can explain up to 18% of total carbon fluxes into the Baltic coastal waters. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Determination of 14C age of inorganic and organic carbon in ancient Siberian permafrost

    Science.gov (United States)

    Onstott, T. C.; Liang, R.; Lau, M.; Vishnivetskaya, T. A.; Lloyd, K. G.; Pfiffner, S. M.; Hodgins, G.; Rivkina, E.

    2017-12-01

    Permafrost represents a large reservoir of ancient carbon that could have an important impact on the global carbon budget during climate warming. Due to the low turnover rate of carbon by microorganisms at subzero temperatures, the persistence of ancient carbon in younger permafrost deposits could also pose challenges for radiocarbon dating of permafrost sediment. We utilized Accelerator Mass Spectrometry to determine the 14C age of inorganic carbon, labile and recalcitrant organic carbon in Siberian permafrost sediment sampled at various depths from 2.9 to 5.6m. The fraction of inorganic carbon (CO2) was collected after acidification using phosphoric acid. The labile (younger) and recalcitrant (old) organic carbon in the subsequent residues were collected after combustion at 400 ºC and 800 ºC, respectively. The percentages of inorganic carbon increased from the youngest (2.9m) to the oldest (5.6m), whereas the fractions for organic carbon varied significantly at different depths. The 14C age determined in the inorganic fraction in the top sample (2.9 m) was 21,760 yr BP and gradually increased to 33,900 yr BP in the relative deeper sediment (3.5 and 5.6 m). Surprisingly, the fraction of "younger" carbon liberated at 400 oC was older than the more recalcitrant and presumably older organic carbon liberated at 800 oC in all cases. Moreover, the 14C age of the younger and older organic carbon fractions did not increase with depth as observed in the carbonate fraction. In particular, the 14C age of the organic carbon in the top sample (38,590-41,700 yr BP) was much older than the deeper samples at depth of 3.5m (18,228-20,158 yr BP) and 5.6m (29,040-38,020 yr BP). It should be noticed that the metabolism of ancient carbon in frozen permafrost may vary at different depths due to the different proportion of necromass and metabolically active microbes. Therefore, additional knowledge about the carbon dynamics of permafrost and more investigation would be required to

  7. Factors affecting distribution patterns of organic carbon in sediments at regional and national scales in China.

    Science.gov (United States)

    Cao, Qingqing; Wang, Hui; Zhang, Yiran; Lal, Rattan; Wang, Renqing; Ge, Xiuli; Liu, Jian

    2017-07-14

    Wetlands are an important carbon reservoir pool in terrestrial ecosystems. Light fraction organic carbon (LFOC), heavy fraction organic carbon (HFOC), and dissolved organic carbon (DOC) were fractionated in sediment samples from the four wetlands (ZR: Zhaoniu River; ZRCW: Zhaoniu River Constructed Wetland; XR: Xinxue River; XRCW: Xinxue River Constructed Wetland). Organic carbon (OC) from rivers and coasts of China were retrieved and statistically analyzed. At regional scale, HFOC stably dominates the deposition of OC (95.4%), whereas DOC and LFOC in ZR is significantly higher than in ZRCW. Concentration of DOC is significantly higher in XRCW (30.37 mg/l) than that in XR (13.59 mg/l). DOC and HFOC notably distinguish between two sampling campaigns, and the deposition of carbon fractions are limited by low nitrogen input. At the national scale, OC attains the maximum of 2.29% at precipitation of 800 mm. OC has no significant difference among the three climate zones but significantly higher in river sediments than in coasts. Coastal OC increases from Bohai Sea (0.52%) to South Sea (0.70%) with a decrease in latitude. This study summarizes the factors affecting organic carbon storage in regional and national scale, and have constructive implications for carbon assessment, modelling, and management.

  8. Prerequisite for highly efficient isoprenoid production by cyanobacteria discovered through the over-expression of 1-deoxy-d-xylulose 5-phosphate synthase and carbon allocation analysis.

    Science.gov (United States)

    Kudoh, Kai; Kawano, Yusuke; Hotta, Shingo; Sekine, Midori; Watanabe, Takafumi; Ihara, Masaki

    2014-07-01

    Cyanobacteria have recently been receiving considerable attention owing to their potential as photosynthetic producers of biofuels and biomaterials. Here, we focused on the production of isoprenoids by cyanobacteria, and aimed to provide insight into metabolic engineering design. To this end, we examined the over-expression of a key enzyme in 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway, 1-deoxy-d-xylulose 5-phosphate synthase (DXS) in the cyanobacterium Synechocystis sp. PCC6803. In the DXS-over-expression strain (Dxs_ox), the mRNA and protein levels of DXS were 4-times and 1.5-times the levels in the wild-type (WT) strain, respectively. The carotenoid content of the Dxs_ox strain (8.4 mg/g dry cell weight [DCW]) was also up to 1.5-times higher than that in the WT strain (5.6 mg/g DCW), whereas the glycogen content dramatically decreased to an undetectable level. These observations suggested that the carotenoid content in the Dxs_ox strain was increased by consuming glycogen, which is a C-storage compound in cyanobacteria. We also quantified the total sugar (145 and 104 mg/g DCW), total fatty acids (31 and 24 mg/g DCW) and total protein (200 and 240 mg/g DCW) content in the WT and Dxs_ox strains, respectively, which were much higher than the carotenoid content. In particular, approximately 54% of the proteins were phycobiliproteins. This study demonstrated the major destinations of carbon flux in cyanobacteria, and provided important insights into metabolic engineering. Target yield can be improved through optimization of gene expression, the DXS protein stabilization, cell propagation depression and restriction of storage compound synthesis. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. Organic carbon sedimentation rates in Asian mangrove coastal ecosystems estimated by 210PB chronology

    International Nuclear Information System (INIS)

    Tateda, Y.; Wattayakorn, G.; Nhan, D.D.; Kasuya, Y.

    2004-01-01

    Organic carbon balance estimation of mangrove coastal ecosystem is important for understanding of Asian coastal carbon budget/flux calculation in global carbon cycle modelling which is powerful tool for the prediction of future greenhouse gas effect and evaluation of countermeasure preference. Especially, the organic carbon accumulation rate in mangrove ecosystem was reported to be important sink of carbon as well as that in boreal peat accumulation. For the estimation of 10 3 years scale organic carbon accumulation rates in mangrove coastal ecosystems, 14 C was used as long term chronological tracer, being useful in pristine mangrove forest reserve area. While in case of mangrove plantation of in coastal area, the 210 Pb is suitable for the estimation of decades scale estimation by its half-life. Though it has possibility of bio-/physical- turbation effect in applying 210 Pb chronology that is offset in case of 10 3 years scale estimation, especially in Asian mangrove ecosystem where the anthropogenic physical turbation by coastal fishery is vigorous.In this paper, we studied the organic carbon and 210 Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand with 7 Be analyses to make sure the negligible effect of above turbation effects on organic carbon accumulation. We finally concluded that 210 Pb was applicable to estimate organic carbon accumulation rates in these ecosystems even though the physical-/bio-turbation is expected. The measured organic carbon accumulation rates using 210 Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were 0.067 4.0 t-C ha -1 y -1 . (author)

  10. The distribution of Th(NO3)4, UO2(NO3)2 and HNO3 between an aqueous phase and an organic tributyl phosphate phase

    International Nuclear Information System (INIS)

    Nakashima, T.; Zimmer, E.

    1984-05-01

    The distribution of Th(NO 3 ) 4 , UO 2 (NO 3 ) 2 and HNO 3 between an aqueous phase and an organic phase, consisting of 30 Vol.% tributyl phosphate in dodecane, has been experimentally investigated. About 120 distribution data have been determined in the concentration ranges that can be seen in the THOREX process for reprocessing spent thorium bearing fuel. Based on the experimental data, two computer programs have been developed which make possible interpolations and, to some extent, extrapolations. With model 1, concentrations in the organic phase can be calculated if that in the aqueous phase are known. With model 2, concentrations in the aqueous phase can be calculated vice versa. Besides the description of the calculation models, a large body of calculated data can be found in this report. In a addition, a calculation mode is presented that makes possible the calculation of distribution data for very low thorium concentrations. (orig.) [de

  11. Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

    Science.gov (United States)

    Spencer, Robert G. M.; Butler, Kenna D.; Aiken, George R.

    2012-09-01

    Dissolved organic carbon (DOC) concentration and chromophoric dissolved organic matter (CDOM) parameters were measured over a range of discharge in 30 U.S. rivers, covering a diverse assortment of fluvial ecosystems in terms of watershed size and landscape drained. Relationships between CDOM absorption at a range of wavelengths (a254, a350, a440) and DOC in the 30 watersheds were found to correlate strongly and positively for the majority of U.S. rivers. However, four rivers (Colorado, Colombia, Rio Grande and St. Lawrence) exhibited statistically weak relationships between CDOM absorption and DOC. These four rivers are atypical, as they either drain from the Great Lakes or experience significant impoundment of water within their watersheds, and they exhibited values for dissolved organic matter (DOM) parameters indicative of autochthonous or anthropogenic sources or photochemically degraded allochthonous DOM and thus a decoupling between CDOM and DOC. CDOM quality parameters in the 30 rivers were found to be strongly correlated to DOM compositional metrics derived via XAD fractionation, highlighting the potential for examining DOM biochemical quality from CDOM measurements. This study establishes the ability to derive DOC concentration from CDOM absorption for the majority of U.S. rivers, describes characteristics of riverine systems where such an approach is not valid, and emphasizes the possibility of examining DOM composition and thus biogeochemical function via CDOM parameters. Therefore, the usefulness of CDOM measurements, both laboratory-based analyses and in situ instrumentation, for improving spatial and temporal resolution of DOC fluxes and DOM dynamics in future studies is considerable in a range of biogeochemical studies.

  12. Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

    Science.gov (United States)

    Spencer, Robert G.M.; Butler, Kenna D.; Aiken, George R.

    2012-01-01

    Dissolved organic carbon (DOC) concentration and chromophoric dissolved organic matter (CDOM) parameters were measured over a range of discharge in 30 U.S. rivers, covering a diverse assortment of fluvial ecosystems in terms of watershed size and landscape drained. Relationships between CDOM absorption at a range of wavelengths (a254, a350, a440) and DOC in the 30 watersheds were found to correlate strongly and positively for the majority of U.S. rivers. However, four rivers (Colorado, Colombia, Rio Grande and St. Lawrence) exhibited statistically weak relationships between CDOM absorption and DOC. These four rivers are atypical, as they either drain from the Great Lakes or experience significant impoundment of water within their watersheds, and they exhibited values for dissolved organic matter (DOM) parameters indicative of autochthonous or anthropogenic sources or photochemically degraded allochthonous DOM and thus a decoupling between CDOM and DOC. CDOM quality parameters in the 30 rivers were found to be strongly correlated to DOM compositional metrics derived via XAD fractionation, highlighting the potential for examining DOM biochemical quality from CDOM measurements. This study establishes the ability to derive DOC concentration from CDOM absorption for the majority of U.S. rivers, describes characteristics of riverine systems where such an approach is not valid, and emphasizes the possibility of examining DOM composition and thus biogeochemical function via CDOM parameters. Therefore, the usefulness of CDOM measurements, both laboratory-based analyses and in situ instrumentation, for improving spatial and temporal resolution of DOC fluxes and DOM dynamics in future studies is considerable in a range of biogeochemical studies.

  13. Preparation of calcium phosphate paste

    International Nuclear Information System (INIS)

    Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa

    2010-01-01

    Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

  14. The effect of carbon dioxide during the desulfurization of flue gas with Mardin-Mazidagi phosphate rock

    Energy Technology Data Exchange (ETDEWEB)

    Melike Sinirkaya; Hatice Bayrakceken; A. Kadir Ozer; M. Sahin Gulaboglu [Ataturk University, Erzurum (Turkey). Department of Chemical Engineering

    2008-11-15

    The effects of temperature, CO{sub 2} concentration and particle size on simultaneous calcination/sulfation of Mardin-Mazidagi phosphate rock in fluidized-bed reactor were investigated. For this, a raw sample was exposed to calcination and sulfation processes in a fluidized-bed reactor to determine the effects of parameters by using a model gas mixture similar to the flue gas composition. The calcination ratio increased with increasing temperature and decreasing particle size, but decreased with increasing CO{sub 2} concentration. In sulfation process, however, sulphate conversion ratio increased with increasing CO{sub 2} ratio and decreased with decreasing particle size. The sulfation reaction is well represented by the shrinking core model and can be divided into two regions with different rate controlling step. For low conversions, the controlling step was found to be chemical reaction at the interface, but the diffusion through the product layer for high conversion. The activation energies for the chemical reaction at the interface and diffusion through the product layer cases were calculated as 100 and 296 kJ mol{sup -1}, respectively. 23 refs., 13 figs., 1 tab.

  15. Engineered carbon (biochar) prepared by direct pyrolysis of Mg-accumulated tomato tissues: characterization and phosphate removal potential.

    Science.gov (United States)

    Yao, Ying; Gao, Bin; Chen, Jianjun; Zhang, Ming; Inyang, Mandu; Li, Yuncong; Alva, Ashok; Yang, Liuyan

    2013-06-01

    An innovative method was developed to produce engineered biochar from magnesium (Mg) enriched tomato tissues through slow pyrolysis in a N2 environment. Tomato plants treated with 25mM Mg accumulated much higher level of Mg in tissue, indicating Mg can be substantially enriched in tomato plants, and pyrolysis process further concentrated Mg in the engineered biochar (8.8% Mg). The resulting Mg-biochar composites (MgEC) showed better sorption ability to phosphate (P) in aqueous solutions compared to the other four tomato leaves biochars. Statistical analysis showed a strong and significant correlation between P removal rate and biochar Mg content (R(2)=0.78, and p<0.001), indicating the enriched Mg in the engineered biochar is the main factor controlling its P removal ability. SEM-EDX, XRD and XPS analyses showed that nanoscale Mg(OH)2 and MgO particles were presented on the surface of MgEC, which serve as the main adsorption sites for aqueous P. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Energy costs of carbon dioxide concentrating mechanisms in aquatic organisms

    Czech Academy of Sciences Publication Activity Database

    Raven, John A.; Beardall, J.; Giordano, Mario

    2014-01-01

    Roč. 121, 2-3 (2014), s. 111-124 ISSN 0166-8595 Institutional support: RVO:61388971 Keywords : carbon dioxide * environmental change * radiation Subject RIV: EE - Microbiology, Virology Impact factor: 3.502, year: 2014

  17. Capturing spatial heterogeneity of soil organic carbon under changing climate

    Science.gov (United States)

    Mishra, U.; Fan, Z.; Jastrow, J. D.; Matamala, R.; Vitharana, U.

    2015-12-01

    The spatial heterogeneity of the land surface affects water, energy, and greenhouse gas exchanges with the atmosphere. Designing observation networks that capture land surface spatial heterogeneity is a critical scientific challenge. Here, we present a geospatial approach to capture the existing spatial heterogeneity of soil organic carbon (SOC) stocks across Alaska, USA. We used the standard deviation of 556 georeferenced SOC profiles previously compiled in Mishra and Riley (2015, Biogeosciences, 12:3993-4004) to calculate the number of observations that would be needed to reliably estimate Alaskan SOC stocks. This analysis indicated that 906 randomly distributed observation sites would be needed to quantify the mean value of SOC stocks across Alaska at a confidence interval of ± 5 kg m-2. We then used soil-forming factors (climate, topography, land cover types, surficial geology) to identify the locations of appropriately distributed observation sites by using the conditioned Latin hypercube sampling approach. Spatial correlation and variogram analyses demonstrated that the spatial structures of soil-forming factors were adequately represented by these 906 sites. Using the spatial correlation length of existing SOC observations, we identified 484 new observation sites would be needed to provide the best estimate of the present status of SOC stocks in Alaska. We then used average decadal projections (2020-2099) of precipitation, temperature, and length of growing season for three representative concentration pathway (RCP 4.5, 6.0, and 8.5) scenarios of the Intergovernmental Panel on Climate Change to investigate whether the location of identified observation sites will shift/change under future climate. Our results showed 12-41 additional observation sites (depending on emission scenarios) will be required to capture the impact of projected climatic conditions by 2100 on the spatial heterogeneity of Alaskan SOC stocks. Our results represent an ideal distribution

  18. Effects of ozonation and temperature on the biodegradation of natural organic matter in biological granular activated carbon filters

    NARCIS (Netherlands)

    Van der Aa, L.T.J.; Rietveld, L.C.; Van Dijk, J.C.

    2011-01-01

    Four pilot (biological) granular activated carbon ((B)GAC) filters were operated to quantify the effects of ozonation and water temperature on the biodegradation of natural organic matter (NOM) in (B)GAC filters. The removal of dissolved organic carbon (DOC), assimilable organic carbon (AOC) and

  19. Effects of ozonation and temperature on biodegradation of natural organic matter in biological granular activated carbon filters

    NARCIS (Netherlands)

    Van der Aa, L.T.J.; Rietveld, L.C.; Van Dijk, J.C.

    2010-01-01

    Four pilot (biological) granular activated carbon ((B)GAC) filters were operated to quantify the effects of ozonation and water temperature on the biodegradation of natural organic matter (NOM) in (B)GAC filters. Removal of dissolved organic carbon (DOC), assimilable organic carbon (AOC) and oxygen

  20. Modeling soil organic carbon with Quantile Regression: Dissecting predictors' effects on carbon stocks

    KAUST Repository

    Lombardo, Luigi

    2017-08-13

    Soil Organic Carbon (SOC) estimation is crucial to manage both natural and anthropic ecosystems and has recently been put under the magnifying glass after the Paris agreement 2016 due to its relationship with greenhouse gas. Statistical applications have dominated the SOC stock mapping at regional scale so far. However, the community has hardly ever attempted to implement Quantile Regression (QR) to spatially predict the SOC distribution. In this contribution, we test QR to estimate SOC stock (0-30 $cm$ depth) in the agricultural areas of a highly variable semi-arid region (Sicily, Italy, around 25,000 $km2$) by using topographic and remotely sensed predictors. We also compare the results with those from available SOC stock measurement. The QR models produced robust performances and allowed to recognize dominant effects among the predictors with respect to the considered quantile. This information, currently lacking, suggests that QR can discern predictor influences on SOC stock at specific sub-domains of each predictors. In this work, the predictive map generated at the median shows lower errors than those of the Joint Research Centre and International Soil Reference, and Information Centre benchmarks. The results suggest the use of QR as a comprehensive and effective method to map SOC using legacy data in agro-ecosystems. The R code scripted in this study for QR is included.

  1. Texture and organic carbon contents do not impact amount of carbon protected in Malagasy soils

    Directory of Open Access Journals (Sweden)

    Tantely Razafimbelo

    2013-06-01

    Full Text Available Soil organic carbon (SOC is usually said to be well correlated with soil texture and soil aggregation. These relations generally suggest a physical and physicochemical protection of SOC within soil aggregates and on soil fine particles, respectively. Because there are few experimental evidences of these relations on tropical soils, we tested the relations of soil variables (SOC and soil aggregate contents, and soil texture with the amount of SOC physically protected in aggregates on a set of 15 Malagasy soils. The soil texture, the SOC and water stable macroaggregate (MA contents and the amount of SOC physically protected inside aggregates, calculated as the difference of C mineralized by crushed and intact aggregates, were characterized. The relation between these variables was established. SOC content was significantly correlated with soil texture (clay+fine silt fraction and with soil MA amount while protected SOC content was not correlated with soil MA amount. This lack of correlation might be attributed to the highest importance of physicochemical protection of SOC which is demonstrated by the positive relation between SOC and clay+fine silt fraction.

  2. Organic carbon sequestration under selected land use in Padang city, West Sumatra, Indonesia

    Science.gov (United States)

    Yulnafatmawita; Yasin, S.

    2018-03-01

    Organic carbon is a potential element to build biomass as well as emitting CO2 to the atmosphere and promotes global warming. This research was aimed to calculate the sequestered Carbon (C) within a 1-m soil depth under selected land use from 6 different sites in Padang city, Indonesia. Disturbed and undisturbed soil samples were taken from several horizons until 100 cm depth at each location. Soil parameters observed were organic carbon (OC), bulk density (BD), and soil texture. The result showed that soil OC content tended to decrease by the depth at all land use types, except under rice field in Kurao-Nanggalo which extremely increased at >65 cm soil depth with the highest carbon stock. The soil organic carbon sequestration from the highest to the lowest according to land use and the location is in the following order mix garden- Kayu Aro > mix garden- Aie Pacah > Rangeland- Parak Laweh >seasonal farming- Teluk Sirih > rice field- Kampuang Jua.

  3. Electrochemistry of closo-dodecaborate dianion and its simple exo-skeletal derivatives at carbon electrodes in aqueous phosphate buffers

    Czech Academy of Sciences Publication Activity Database

    Fojt, Lukáš; Fojta, Miroslav; Grüner, Bohumír; Vespalec, Radim

    2013-01-01

    Roč. 707, OCT152013 (2013), s. 38-42 ISSN 1572-6657 R&D Projects: GA ČR(CZ) GBP206/12/G151 Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 ; RVO:61388980 Keywords : Boron cluster * Dodecarborate * Glasy carbon electrode Subject RIV: BO - Biophysics; CA - Inorganic Chemistry (UACH-T) Impact factor: 2.871, year: 2013

  4. Assessment of the potential of urban organic carbon dynamics to off-set urban anthropogenic emissions

    Science.gov (United States)

    Gottschalk, P.; Churkina, G.; Wattenbach, M.; Cubasch, U.

    2010-12-01

    The impact of urban systems on current and future global carbon emissions has been a focus of several studies. Many mitigation options in terms of increasing energy efficiency are discussed. However, apart from technical mitigation potential urban systems also have a considerable biogenic potential to mitigate carbon through an optimized management of organic carbon pools of vegetation and soil. Berlin city area comprises almost 50% of areas covered with vegetation or largely covered with vegetation. This potentially offers various areas for carbon mitigation actions. To assess the mitigation potentials our first objective is to estimate how large current vegetation and soil carbon stocks of Berlin are. We use publicly available forest and soil inventories to calculate soil organic carbon of non-pervious areas and forest standing biomass carbon. This research highlights data-gaps and assigns uncertainty ranges to estimated carbon resources. The second objective is to assess the carbon mitigation potential of Berlin’s vegetation and soils using a biogeochemical simulation model. BIOME-BGC simulates carbon-, nitrogen- and water-fluxes of ecosystems mechanistically. First, its applicability for Berlin forests is tested at selected sites. A spatial application gives an estimate of current net carbon fluxes. The application of such a model allows determining the sensitivity of key ecosystem processes (e.g. carbon gains through photosynthesis, carbon losses through decomposition) towards external drivers. This information can then be used to optimise forest management in terms of carbon mitigation. Initial results of Berlin’s current carbon stocks and its spatial distribution and preliminary simulations results will be presented.

  5. Assimilation of aged organic carbon in a glacial river food web

    Science.gov (United States)

    Fellman, J.; Hood, E. W.; Raymond, P. A.; Bozeman, M.; Hudson, J.; Arimitsu, M.

    2013-12-01

    Identifying the key sources of organic carbon supporting fish and invertebrate consumers is fundamental to our understanding of stream ecosystems. Recent laboratory bioassays highlight that aged organic carbon from glacier environments is highly bioavailable to stream bacteria relative to carbon originating from ice-free areas. However, there is little evidence suggesting that this aged, bioavailable organic carbon is also a key basal carbon source for stream metazoa. We used natural abundance of Δ14C, δ13C, and δ15N to determine if fish and invertebrate consumers are subsidized by aged organic carbon in a glacial river in southeast Alaska. We collected biofilm, leaf litter, three different species of macroinvertebrates, and resident juvenile salmonids from a reference stream and two sites (one site is directly downstream of the glacial outflow and one site is upstream of the tidal estuary) on the heavily glaciated Herbert River. Key producers, fish, and invertebrate consumers in the reference stream had carbon isotope values that ranged from -26 to -30‰ for δ13C and from -12 to 53‰ for Δ14C, reflecting a food web sustained mainly on contemporary primary production. In contrast, biofilm in the two glacial sites was highly Δ14C depleted (-203 to -215‰) relative to the reference site. Although biofilm may consist of both bacteria and benthic algae utilizing carbon depleted in Δ14C, δ13C values for biofilm (-24.1‰), dissolved inorganic carbon (-5.9‰), and dissolved organic carbon (-24.0‰) suggest that biofilm consist of bacteria sustained in part by glacier-derived, aged organic carbon. Invertebrate consumers (mean Δ14C of -80.5, mean δ13C of -26.5) and fish (mean Δ14C of -63.3, mean δ13C of -25.7) in the two glacial sites had carbon isotope values similar to biofilm. These results similarly show that aged organic carbon is incorporated into the metazoan food web. Overall, our findings indicate that continued watershed deglaciation and

  6. Autochthonous and allochthonous contributions of organic carbon to microbial food webs in Svalbard fjords

    OpenAIRE

    Holding, J.M.; Duarte, C.M.; Delgado-Huertas, A.; Soetaert, K.; Vonk, J.E.; Agusti, S.; Wassmann, P.; Middelburg, J.

    2017-01-01

    Rising temperatures in the Arctic Ocean are causing sea ice and glaciers to melt at record breaking rates, which has consequences for carbon cycling in the Arctic Ocean that are yet to be fully understood. Microbial carbon cycling is driven by internal processing of in situ produced organic carbon (OC), however recent research suggests that melt water from sea ice and glaciers could introduce an allochthonous source of OC to the microbial food web with ramifications for the metabolic balance ...

  7. Effects of Rice Straw and Its Biochar Addition on Soil Labile Carbon and Soil Organic Carbon

    Institute of Scientific and Technical Information of China (English)

    YIN Yun-feng; HE Xin-hua; GAO Ren; MA Hong-liang; YANG Yu-sheng

    2014-01-01

    Whether the biochar amendment could affect soil organic matter (SOM) turnover and hence soil carbon (C) stock remains poorly understood. Effects of the addition of 13C-labelled rice straw or its pyrolysed biochar at 250 or 350°C to a sugarcane soil (Ferrosol) on soil labile C (dissolved organic C, DOC;microbial biomass C, MBC;and mineralizable C, MC) and soil organic C (SOC) were investigated after 112 d of laboratory incubation at 25°C. Four treatments were examined as (1) the control soil without amendment (Soil);(2) soil plus 13C-labelled rice straw (Soil+Straw);(3) soil plus 250°C biochar (Soil+B250) and (4) soil plus 350°C biochar (Soil+B350). Compared to un-pyrolysed straw, biochars generally had an increased aryl C, carboxyl C, C and nitrogen concentrations, a decreased O-alkyl C and C:N ratio, but similar alkyl C and d13C (1 742-1 877‰). Among treatments, signiifcant higher DOC, MBC and MC derived from the new C (straw or biochar) ranked as Soil+Straw>Soil+B250>Soil+B350, whilst signiifcant higher SOC from the new C as Soil+B250>Soil+Straw≈Soil+B350. Compared to Soil, DOC and MBC derived from the native soil were decreased under straw or biochar addition, whilst MC from the native soil was increased under straw addition but decreased under biochar addition. Meanwhile, native SOC was similar among the treatments, irrespective of the straw or biochar addition. Compared to Soil, signiifcant higher total DOC and total MBC were under Soil+Straw, but not under Soil+B250 and Soil+B350, whilst signiifcant higher total MC and total SOC were under straw or biochar addition, except for MC under Soil+B350. Our results demonstrated that the application of biochar to soil may be an appropriate management practice for increasing soil C storage.

  8. The role of hydrology in annual organic carbon loads and terrestrial organic matter export from a midwestern agricultural watershed

    Science.gov (United States)

    Dalzell, Brent J.; Filley, Timothy R.; Harbor, Jon M.

    2007-03-01

    Defining the control that hydrology exerts on organic carbon (OC) export at the watershed scale is important for understanding how the source and quantity of OC in streams and rivers is influenced by climate change or by landscape drainage. To this end, molecular (lignin phenol), stable carbon isotope, and dissolved organic carbon (DOC) data were collected over a range of flow conditions to examine the influence of hydrology on annual OC export from an 850 km 2 Midwestern United States agricultural watershed located in west central Indiana. In years 2002 and 2003, modeled annual DOC loads were 19.5 and 14.1 kg ha -1yr -1, while 71% and 85%, respectively, of the total annual OC was exported in flow events occurring during less than 20% of that time. These results highlight the importance of short-duration, high-discharge events (common in smaller watersheds) in controlling annual OC export. Based on reported increases in annual stream discharge coupled with current estimates of DOC export, annual DOC loads in this watershed may have increased by up to 40% over the past 50 years. Molecular (lignin phenol) characterization of quantity and relative degradation state of terrestrial OC shows as much temporal variability of lignin parameters (in high molecular weight dissolved organic carbon) in this one watershed as that demonstrated in previously published studies of dissolved organic matter in the Mississippi and Amazon Rivers. These results suggest that hydrologic variability is at least as important in determining the nature and extent of OC export as geographic variability. Moreover, molecular and bulk stable carbon isotope data from high molecular weight dissolved organic carbon and colloidal organic carbon showed that increased stream flow from the study watershed was responsible for increased export of agriculturally derived OC. When considered in the context of results from other studies that show the importance of flood events and in-stream processing of

  9. Assessment of soil organic carbon stocks under future climate and land cover changes in Europe.

    Science.gov (United States)

    Yigini, Yusuf; Panagos, Panos

    2016-07-01

    Soil organic carbon plays an important role in the carbon cycling of terrestrial ecosystems, variations in soil organic carbon stocks are very important for the ecosystem. In this study, a geostatistical model was used for predicting current and future soil organic carbon (SOC) stocks in Europe. The first phase of the study predicts current soil organic carbon content by using stepwise multiple linear regression and ordinary kriging and the second phase of the study projects the soil organic carbon to the near future (2050) by using a set of environmental predictors. We demonstrate here an approach to predict present and future soil organic carbon stocks by using climate, land cover, terrain and soil data and their projections. The covariates were selected for their role in the carbon cycle and their availability for the future model. The regression-kriging as a base model is predicting current SOC stocks in Europe by using a set of covariates and dense SOC measurements coming from LUCAS Soil Database. The base model delivers coefficients for each of the covariates to the future model. The overall model produced soil organic carbon maps which reflect the present and the future predictions (2050) based on climate and land cover projections. The data of the present climate conditions (long-term average (1950-2000)) and the future projections for 2050 were obtained from WorldClim data portal. The future climate projections are the recent climate projections mentioned in the Fifth Assessment IPCC report. These projections were extracted from the global climate models (GCMs) for four representative concentration pathways (RCPs). The results suggest an overall increase in SOC stocks by 2050 in Europe (EU26) under all climate and land cover scenarios, but the extent of the increase varies between the climate model and emissions scenarios. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Organic carbon and reducing conditions lead to cadmium immobilization by secondary Fe mineral formation in a pH-neutral soil.

    Science.gov (United States)

    Muehe, E Marie; Adaktylou, Irini J; Obst, Martin; Zeitvogel, Fabian; Behrens, Sebastian; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas

    2013-01-01

    Cadmium (Cd) is of environmental relevance as it enters soils via Cd-containing phosphate fertilizers and endangers human health when taken up by crops. Cd is known to associate with Fe(III) (oxyhydr)oxides in pH-neutral to slightly acidic soils, though it is not well understood how the interrelation of Fe and Cd changes under Fe(III)-reducing conditions. Therefore, we investigated how the mobility of Cd changes when a Cd-bearing soil is faced with organic carbon input and reducing conditions. Using fatty acid profiles and quantitative PCR, we found that both fermenting and Fe(III)-reducing bacteria were stimulated by organic carbon-rich conditions, leading to significant Fe(III) reduction. The reduction of Fe(III) minerals was accompanied by increasing soil pH, increasing dissolved inorganic carbon, and decreasing Cd mobility. SEM-EDX mapping of soil particles showed that a minor fraction of Cd was transferred to Ca- and S-bearing minerals, probably carbonates and sulfides. Most of the Cd, however, correlated with a secondary iron mineral phase that was formed during microbial Fe(III) mineral reduction and contained mostly Fe, suggesting an iron oxide mineral such as magnetite (Fe3O4). Our data thus provide evidence that secondary Fe(II) and Fe(II)/Fe(III) mixed minerals could be a sink for Cd in soils under reducing conditions, thus decreasing the mobility of Cd in the soil.

  11. Effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen by the scleractinian coral Montipora digitata

    Science.gov (United States)

    Tanaka, Y.; Ogawa, H.; Miyajima, T.

    2010-09-01

    The effects of nutrient enrichment on the release of dissolved organic carbon and nitrogen (DOC and DON, respectively) from the coral Montipora digitata were investigated in the laboratory. Nitrate (NO3 -) and phosphate (PO4 3-) were supplied to the aquarium to get the final concentrations of 10 and 0.5 μmol l-1, respectively, and the corals were incubated for 8 days. The release rate of DON per unit coral surface area significantly decreased after the nutrient enrichment, while the release rate of DOC was constant. Because the chlorophyll a (chl a) content of zooxanthellae per unit surface area increased, the release rate of DOC significantly decreased when normalized to unit chl a. These results suggested that the incorporation of NO3 - and PO4 3- stimulated the synthesis of new cellular components in the coral colonies and consequently, reduced extracellular release of DOC and DON. Actually, significant increase in N and P contents relative to C content was observed in the coral’s tissue after the nutrient enrichment. The present study has concluded that inorganic nutrient enrichment not only affects coral-algal metabolism inside the colony but also affects a microbial community around the coral because the organic matter released from corals functions as energy carrier in the coral reef ecosystem.

  12. TAILORING ACTIVATED CARBONS FOR ENHANCED REMOVAL OF NATURAL ORGANIC MATTER FROM NATURAL WATERS. (R828157)

    Science.gov (United States)

    Several pathways have been employed to systematically modify two granular activated carbons (GACs), F400 (coal-based) and Macro (wood-based), for examining adsorption of dissolved natural organic matter (DOM) from natural waters. A total of 24 activated carbons with different ...

  13. Biodegradability of dissolved organic carbon in permafrost soils and aquatic systems : A meta-analysis

    NARCIS (Netherlands)

    Vonk, J. E.; Tank, S. E.; Mann, P. J.; Spencer, R. G M; Treat, C. C.; Striegl, R. G.; Abbott, B. W.; Wickland, K. P.

    2015-01-01

    As Arctic regions warm and frozen soils thaw, the large organic carbon pool stored in permafrost becomes increasingly vulnerable to decomposition or transport. The transfer of newly mobilized carbon to the atmosphere and its potential influence upon climate change will largely depend on the

  14. Light absorbing organic carbon from prescribed and laboratory biomass burning and gasoline vehicle emissions

    Science.gov (United States)

    The light absorption of carbonaceous aerosols plays an important role in the atmospheric radiation balance. Light-absorbing organic carbon (OC), also called brown carbon (BrC), from laboratory-based biomass burning (BB) has been studied intensively to understand the contribution ...

  15. Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions

    Directory of Open Access Journals (Sweden)

    Flávia Bottino

    2016-06-01

    Full Text Available Abstract Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40 °C. Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days. After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic. However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity and carbon release.

  16. Comparing soil organic carbon dynamics in plantation and secondary forest in wet tropics in Puerto Rico

    Science.gov (United States)

    LI YIQING; MING XU; ZOU XIAOMING; PEIJUN SHI§; YAOQI ZHANG

    2005-01-01

    We compared the soil carbon dynamics between a pine plantation and a secondary forest, both of which originated from the same farmland abandoned in 1976 with the same cropping history and soil conditions, in the wet tropics in Puerto Rico from July 1996 to June 1997. We found that the secondary forest accumulated the heavy-fraction organic carbon (HF-OC) measured by...

  17. Tracing organic matter sources of estuarine tidal flat nematodes with stable carbon isotopes

    NARCIS (Netherlands)

    Moens, T.; Luyten, C.; Middelburg, J.J.; Herman, P.M.J.; Vincx, M.

    2002-01-01

    The present study explores the use of stable carbon isotopes to trace organic matter sources of intertidal nematodes in the Schelde estuary (SW Netherlands). Stable carbon isotope signatures of nematodes from a saltmarsh and 4 tidal flat stations were determined in spring and winter situations, and

  18. Impacts of soil redistribution on the transport and fate of organic carbon in loess soils

    NARCIS (Netherlands)

    Wang, X.

    2014-01-01

    Soil erosion is an important environmental process leading to loss of topsoil including carbon (C) and nutrients, reducing soil quality and loss of biomass production. So far, the fate of soil organic carbon (SOC) in eroding landscapes is not yet fully understood and remains an important uncertainty

  19. Satellite observation of particulate organic carbon dynamics on the Louisiana continental shelf

    Science.gov (United States)

    Particulate organic carbon (POC) plays an important role in coastal carbon cycling and the formation of hypoxia. Yet, coastal POC dynamics are often poorly understood due to a lack of long-term POC observations and the complexity of coastal hydrodynamic and biogeochemical process...

  20. Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions.

    Science.gov (United States)

    Bottino, Flávia; Cunha-Santino, Marcela Bianchessi; Bianchini, Irineu

    2016-01-01

    Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40°C). Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively) were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days). After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic). However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity) and carbon release. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  1. Measurement of stable isotope ratio of organic carbon in water samples

    International Nuclear Information System (INIS)

    Fujii, Toshihiro; Otsuki, Akira

    1977-01-01

    A new method for the measurement of stable isotope ratios was investigated and applied to organic carbon's isotope ratio measurements in water samples. A few river water samples from Tsuchiura city were tested. After the wet oxidation of organic carbons to carbon dioxide in a sealed ampoule, the isotope ratios were determined with the gas chromatograph-quadrupole mass spectrometer combined with a total organic carbon analyser, under the dynamic conditions. The GC-MS had been equipped with the multiple ion detector-digital integrator system. The ion intensities at m/e 44 and 45 were simultaneously measured at a switching rate of 1 ms. The measurements with carbon dioxide acquired from sodium carbonate (53 μg) gave the isotope ratios with the variation coefficient of 0.62%. However, the variation coefficients obtained from organic carbons in natural water samples were 2 to 3 times as high as that from sodium carbonate. This method is simple and rapid and may be applied to various fields especially in biology and medicine. (auth.)

  2. Chlorophyll 'a' particulate organic carbon and suspended load from the mangrove areas of Cochin backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Sheeba, P.; Devi, K.S.; Balasubramanian, T.; Sankaranarayanan, V.N.

    Chlorophyll 'a' Particulate Organic Carbon and suspended load were estimated for one year from two distinct mangrove areas of Cochin backwaters, viz. Puthuvypeen and Nettoor. Environmental parameters like tau degrees C, S ppt and pH were also...

  3. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest canopy...

  4. LBA-ECO CD-02 Carbon, Nitrogen, Oxygen Stable Isotopes in Organic Material, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports the measurement of stable carbon, nitrogen, and oxygen isotope ratios in organic material (plant, litter and soil samples) in forest...

  5. Foraminiferal assemblages and organic carbon relationship in benthic marine ecosystem of Western Indian Continental Shelf

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    that Ammobaculites agglutinans (d'Orbigny) and Ammonia spp have positive (direct) tendency towards organic carbon while miliolids (Quinqueloqulina spp, Spiroloculina spp and Triloculina spp Florilus-Nonion and Nonionella spp have negative (inverse) tendency...

  6. Studies on structure and organization of calcium carbonate deposits in algae

    Digital Repository Service at National Institute of Oceanography (India)

    Kerkar, V.; Untawale, A.G.

    The structure and organization of calcium carbonate deposits is studied in species of Halimeda, Udotea, Neomeris (Chlorophyta) and Padina (Phaeophyta). It was found that in Halimeda aragonite deposition takes place outside the cell wall...

  7. Distribution of phosphorus and organic carbon in the nearshore sediments of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Rajamanickam, G.V.; Setty, M.G.A.P.

    Samples collected from sediment water interface from the inner shelf region of Goa coast are examined for their phosphorus and organic carbon, which indicate the geochemical environment under which the present day deposits are laid down...

  8. The addition of organic carbon and nitrate affects reactive transport of heavy metals in sandy aquifers

    KAUST Repository

    Satyawali, Yamini; Seuntjens, Piet; Van Roy, Sandra; Joris, Ingeborg; Vangeel, Silvia; Dejonghe, Winnie; Vanbroekhoven, Karolien

    2011-01-01

    Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy

  9. Response to Comment on "Dilution limits dissolved organic carbon utilization in the deep ocean"

    KAUST Repository

    Arrieta, J M; Mayol, E.; Hansman, R. L.; Herndl, G. J.; Dittmar, T.; Duarte, Carlos M.

    2015-01-01

    Our recent finding that dilution limits dissolved organic carbon (DOC) utilization in the deep ocean has been criticized based on the common misconception that lability equates to rapid and complete utilization. Even when considering

  10. ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS

    Science.gov (United States)

    Kennedy, J.

    1959-04-14

    An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

  11. Towards a paradigm shift in the modeling of soil organic carbon decomposition for earth system models

    Science.gov (United States)

    He, Yujie

    Soils are the largest terrestrial carbon pools and contain approximately 2200 Pg of carbon. Thus, the dynamics of soil carbon plays an important role in the global carbon cycle and climate system. Earth System Models are used to project future interactions between terrestrial ecosystem carbon dynamics and climate. However, these models often predict a wide range of soil carbon responses and their formulations have lagged behind recent soil science advances, omitting key biogeochemical mechanisms. In contrast, recent mechanistically-based biogeochemical models that explicitly account for microbial biomass pools and enzyme kinetics that catalyze soil carbon decomposition produce notably different results and provide a closer match to recent observations. However, a systematic evaluation of the advantages and disadvantages of the microbial models and how they differ from empirical, first-order formulations in soil decomposition models for soil organic carbon is still needed. This dissertation consists of a series of model sensitivity and uncertainty analyses and identifies dominant decomposition processes in determining soil organic carbon dynamics. Poorly constrained processes or parameters that require more experimental data integration are also identified. This dissertation also demonstrates the critical role of microbial life-history traits (e.g. microbial dormancy) in the modeling of microbial activity in soil organic matter decomposition models. Finally, this study surveys and synthesizes a number of recently published microbial models and provides suggestions for future microbial model developments.

  12. Spatial Mapping of Organic Carbon in Returned Samples from Mars

    Science.gov (United States)

    Siljeström, S.; Fornaro, T.; Greenwalt, D.; Steele, A.

    2018-04-01

    To map organic material spatially to minerals present in the sample will be essential for the understanding of the origin of any organics in returned samples from Mars. It will be shown how ToF-SIMS may be used to map organics in samples from Mars.

  13. Evaluation of Soil Quality Using Labile Organic Carbon and Carbon Management Indices in Agricultural Lands of Neyriz, Fars Province

    Directory of Open Access Journals (Sweden)

    Anahid Salmanpour

    2017-02-01

    Full Text Available Introduction: Soil organic matter is considered as an indicator of soil quality, because of its role on the stability of soil structure, water holding capacity, microbial activity, storage and release of nutrients. Although changes and trends of organic matter are assessed on the basis of organic carbon, it responds slowly to changes of soil management. Therefore, identifying sensitive components of organic carbon such as carbon labile lead to better understanding of the effect of land use change and soil management on soil quality. The main components of sustainable agriculture in arid and semi-arid regions are the amount of water; and soil and water salinity. Water deficit and irrigation with saline water are important limiting factors for cropping and result in adverse effects on soil properties and soil quality. Soil carbon changes is a function of addition of plant debris and removal of it from soil by its decomposition. If the amount of organic carbon significantly reduced due to the degradation of the soil physical and chemical properties and soil quality, agricultural production will face serious problems. To this end, this study was done to evaluate soil quality using soil labile carbon and soil carbon management indices in some agricultural lands of Neyriz area, Fars province, Iran. Materials and Methods: Five fields were selected in two regions, Dehfazel and Tal-e-mahtabi, consisted of irrigated wheat and barley with different amount of irrigation water and water salinity levels. Three farms were located in Dehfazel and two farms in Tal-e-Mahtabi region. In each farm, three points were randomly selected and soil samples were collected from 0-40 cm of the surface layer. Plant samples were taken from a 1x1 square meter and grain crop yield was calculated per hectare. Water samples were obtained in each region from the wells at the last irrigation. Physical and chemical characteristics of the soil and water samples were determined. Soil

  14. Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: a baseline for ocean acidification impact assessment

    Science.gov (United States)

    Trull, Thomas W.; Passmore, Abraham; Davies, Diana M.; Smit, Tim; Berry, Kate; Tilbrook, Bronte

    2018-01-01

    The Southern Ocean provides a vital service by absorbing about one-sixth of humankind's annual emissions of CO2. This comes with a cost - an increase in ocean acidity that is expected to have negative impacts on ocean ecosystems. The reduced ability of phytoplankton and zooplankton to precipitate carbonate shells is a clearly identified risk. The impact depends on the significance of these organisms in Southern Ocean ecosystems, but there is very little information on their abundance or distribution. To quantify their presence, we used coulometric measurement of particulate inorganic carbonate (PIC) on particles filtered from surface seawater into two size fractions: 50-1000 µm to capture foraminifera (the most important biogenic carbonate-forming zooplankton) and 1-50 µm to capture coccolithophores (the most important biogenic carbonate-forming phytoplankton). Ancillary measurements of biogenic silica (BSi) and particulate organic carbon (POC) provided context, as estimates of the biomass of diatoms (the highest biomass phytoplankton in polar waters) and total microbial biomass, respectively. Results for nine transects from Australia to Antarctica in 2008-2015 showed low levels of PIC compared to Northern Hemisphere polar waters. Coccolithophores slightly exceeded the biomass of diatoms in subantarctic waters, but their abundance decreased more than 30-fold poleward, while diatom abundances increased, so that on a molar basis PIC was only 1 % of BSi in Antarctic waters. This limited importance of coccolithophores in the Southern Ocean is further emphasized in terms of their associated POC, representing less than 1 % of total POC in Antarctic waters and less than 10 % in subantarctic waters. NASA satellite ocean-colour-based PIC estimates were in reasonable agreement with the shipboard results in subantarctic waters but greatly overestimated PIC in Antarctic waters. Contrastingly, the NASA Ocean Biogeochemical Model (NOBM) shows coccolithophores as overly

  15. Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: a baseline for ocean acidification impact assessment

    Directory of Open Access Journals (Sweden)

    T. W. Trull

    2018-01-01

    Full Text Available The Southern Ocean provides a vital service by absorbing about one-sixth of humankind's annual emissions of CO2. This comes with a cost – an increase in ocean acidity that is expected to have negative impacts on ocean ecosystems. The reduced ability of phytoplankton and zooplankton to precipitate carbonate shells is a clearly identified risk. The impact depends on the significance of these organisms in Southern Ocean ecosystems, but there is very little information on their abundance or distribution. To quantify their presence, we used coulometric measurement of particulate inorganic carbonate (PIC on particles filtered from surface seawater into two size fractions: 50–1000 µm to capture foraminifera (the most important biogenic carbonate-forming zooplankton and 1–50 µm to capture coccolithophores (the most important biogenic carbonate-forming phytoplankton. Ancillary measurements of biogenic silica (BSi and particulate organic carbon (POC provided context, as estimates of the biomass of diatoms (the highest biomass phytoplankton in polar waters and total microbial biomass, respectively. Results for nine transects from Australia to Antarctica in 2008–2015 showed low levels of PIC compared to Northern Hemisphere polar waters. Coccolithophores slightly exceeded the biomass of diatoms in subantarctic waters, but their abundance decreased more than 30-fold poleward, while diatom abundances increased, so that on a molar basis PIC was only 1 % of BSi in Antarctic waters. This limited importance of coccolithophores in the Southern Ocean is further emphasized in terms of their associated POC, representing less than 1 % of total POC in Antarctic waters and less than 10 % in subantarctic waters. NASA satellite ocean-colour-based PIC estimates were in reasonable agreement with the shipboard results in subantarctic waters but greatly overestimated PIC in Antarctic waters. Contrastingly, the NASA Ocean Biogeochemical Model (NOBM shows

  16. Fossil organic carbon in wastewater and its fate in treatment plants.

    Science.gov (United States)

    Law, Yingyu; Jacobsen, Geraldine E; Smith, Andrew M; Yuan, Zhiguo; Lant, Paul

    2013-09-15

    This study reports the presence of fossil organic carbon in wastewater and its fate in wastewater treatment plants. The findings pinpoint the inaccuracy of current greenhouse gas accounting guidelines which defines all organic carbon in wastewater to be of biogenic origin. Stable and radiocarbon isotopes ((13)C and (14)C) were measured throughout the process train in four municipal wastewater treatment plants equipped with secondary activated sludge treatment. Isotopic mass balance analyses indicate that 4-14% of influent total organic carbon (TOC) is of fossil origin with concentrations between 6 and 35 mg/L; 88-98% of this is removed from the wastewater. The TOC mass balance analysis suggests that 39-65% of the fossil organic carbon from the influent is incorporated into the activated sludge through adsorption or from cell assimilation while 29-50% is likely transformed to carbon dioxide (CO2) during secondary treatment. The fossil organic carbon fraction in the sludge undergoes further biodegradation during anaerobic digestion with a 12% decrease in mass. 1.4-6.3% of the influent TOC consists of both biogenic and fossil carbon is estimated to be emitted as fossil CO2 from activated sludge treatment alone. The results suggest that current greenhouse gas accounting guidelines, which assume that all CO2 emission from wastewater is biogenic may lead to underestimation of emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Styrene–tin (IV) phosphate nanocomposite for photocatalytic degradation of organic dye in presence of visible light

    Energy Technology Data Exchange (ETDEWEB)

    Rathore, Bhim Singh [School of Chemistry, Shoolini University, Solan 173 212, Himachal Pradesh (India); Department of Chemistry, Government P.G. College, Solan 173 212, Himachal Pradesh (India); Pathania, Deepak, E-mail: dpathania74@gmail.com [School of Chemistry, Shoolini University, Solan 173 212, Himachal Pradesh (India)

    2014-09-01

    Highlights: • Styrene–tin (IV) phosphate nanocomposite (ST/TPNC) ion exchanger was chemically prepared by simple sol–gel method at pH 0–1. • ST/TPNC exhibited higher ion exchange capacity as compared to its inorganic component. • ST/TPNC retained about 35.5% of the initial value of ion exchange capacity after heating up to 400 °C. • ST/TPNC was used as efficient photocatalyst for the degradation of MB dye from aqueous system in the presence of solar light. • The pH titrations studies confirmed the monofunctional strong cationic nature of ST/TPNC. - Abstract: Styrene–tin (IV) phosphate nanocomposite (ST/TPNC) ion exchanger was used as efficient photocatalyst for the degradation of methylene blue dye from aqueous system in the presence of solar light. ST/TPNC exhibited a high efficiency in heterogeneous photocatalytic process for the removal of MB from the water system. The degradation efficiency after 2 h illumination was 80%. The degradation of MB follows the pseudo-first-order kinetics with rate constant 0.00702 min{sup −1}. The nanocomposite ion exchanger was explored for its ion exchange capacity, pH titration, elution behavior, elution concentration and distribution coefficient (K{sub d}). ST/TPNC exhibited a higher ion exchange capacity (1.83 meg/g) compared to its inorganic counterpart (0.55 meg/g). ST/TPNC was characterized using some techniques such as Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and thermogravimetric analysis (TGA)

  18. Evaluation of Anaerobic Biodegradation of Organic Carbon Extracted from Aquifer Sediment

    OpenAIRE

    Kelly, Catherine Aileen

    2006-01-01

    In conjunction with ongoing studies to develop a method for quantifying potentially biodegradable organic carbon (Rectanus et al 2005), this research was conducted to evaluate the extent to which organic carbon extracted using this method will biodegrade in anaerobic environments. The ultimate goal is to use this method for the evaluation of chloroethene contaminated sites in order to estimate the long-term sustainability of monitored natural attenuation (MNA) as a remediation strategy. Alt...

  19. 3D hybrid-porous carbon derived from carbonization of metal organic frameworks for high performance supercapacitors

    Science.gov (United States)

    Bao, Weizhai; Mondal, Anjon Kumar; Xu, Jing; Wang, Chengyin; Su, Dawei; Wang, Guoxiu

    2016-09-01

    We report a rational design and synthesis of 3D hybrid-porous carbon with a hierarchical pore architecture for high performance supercapacitors. It contains micropores (<2 nm diameter) and mesopores (2-4 nm), derived from carbonization of unique porous metal organic frameworks (MOFs). Owning to the synergistic effect of micropores and mesopores, the hybrid-porous carbon has exceptionally high ion-accessible surface area and low ion diffusion resistance, which is desired for supercapacitor applications. When applied as electrode materials in supercapacitors, 3D hybrid-porous carbon demonstrates a specific capacitance of 332 F g-1 at a constant charge/discharge current of 500 mA g-1. The supercapacitors can endure more than 10,000 cycles without degradation of capacitance.

  20. Activated carbon enhancement with covalent organic polymers: An innovative material for application in water purification and carbon dioxide capture

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    Covalent organic polymers (COPs) have emerged as one of the leading advanced materials for environmental applications, such as the capture and recovery of carbon dioxide and the removal of contaminants from polluted water.1–4 COPs exhibit many remarkable properties that other leading advanced mat...

  1. Impact of exotic earthworms on organic carbon sorption on mineral surfaces and soil carbon inventories in a northern hardwood forest

    Science.gov (United States)

    Amy Lyttle; Kyungsoo Yoo; Cindy Hale; Anthony Aufdenkampe; Stephen D. Sebestyen; Kathryn Resner; Alex. Blum

    2015-01-01

    Exotic earthworms are invading forests in North America where native earthworms have been absent since the last glaciation. These earthworms bioturbate soils and may enhance physical interactions between minerals and organic matter (OM), thus affecting mineral sorption of carbon (C) which may affect C cycling. We quantitatively show how OM-mineral sorption and soil C...

  2. Assessment of Soil Organic Carbon Stock of Temperate Coniferous Forests in Northern Kashmir

    Directory of Open Access Journals (Sweden)

    Davood A. Dar

    2015-02-01

    Full Text Available  Soil organic carbon (SOC estimation in temperate forests of the Himalaya is important to estimate their contribution to regional, national and global carbon stocks. Physico chemical properties of soil were quantified to assess soil organic carbon density (SOC and SOC CO2 mitigation density at two soil depths (0-10 and 10-20 cms under temperate forest in the Northern region of Kashmir Himalayas India. The results indicate that conductance, moisture content, organic carbon and organic matter were significantly higher while as pH and bulk density were lower at Gulmarg forest site. SOC % was ranging from 2.31± 0.96 at Gulmarg meadow site to 2.31 ± 0.26 in Gulmarg forest site. SOC stocks in these temperate forests were from 36.39 ±15.40 to 50.09 ± 15.51 Mg C ha-1. The present study reveals that natural vegetation is the main contributor of soil quality as it maintained the soil organic carbon stock. In addition, organic matter is an important indicator of soil quality and environmental parameters such as soil moisture and soil biological activity change soil carbon sequestration potential in temperate forest ecosystems.DOI: http://dx.doi.org/10.3126/ije.v4i1.12186International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15; page: 161-178

  3. The Role of Reactive Iron in Organic Carbon Burial of the Wax Lake Delta, Louisiana

    Science.gov (United States)

    Bianchi, T. S.; Shields, M. R.; Gelinas, Y.; Allison, M. A.; Twilley, R.

    2016-02-01

    Deltaic systems are responsible for 41% of the total organic carbon buried on continental shelves (Smith et al., 2015). Furthermore, 21.5 ± 8.6% of the organic carbon in marine sediments is reported to be associated to reactive iron phases (Lalonde et al., 2012). Here, we examine the role of reactive iron in preserving organic carbon across a chronosequence in deltaic soils/sediments of the Wax Lake Delta, Louisiana. This prograding delta is part of the youngest subdelta of the Mississippi River Delta and serves as a model for deltas in an active progradational stage. We report the proportion, δ13C, lignin phenol content, and fatty acid content of organic carbon associated to iron in three unique environments along the delta topset. We found that over 15 % of the organic carbon in the top 0.5 meters was associated to reactive iron phases at our sampling locations. However, this amount varied between the mudflat, meadow, and canopy dominated sites. Moreover, the type of binding shifts from 1:1 sorption in the sediment dominated (mudflat) region to chelation/co-precipitation in the more soil-dominated regions. Acidic lignin phenols are preferentially sorbed in the mudflat region, which likely occurs pre-depositionally. These results add to our knowledge of the carbon burial processes in young deltas and present new questions about the selective preservation of organic compounds in deltaic sediments.

  4. Thermo-tolerant phosphate-solubilizing microbes for multi-functional biofertilizer preparation.

    Science.gov (United States)

    Chang, Cheng-Hsiung; Yang, Shang-Shyng

    2009-02-01

    In order to prepare the multi-functional biofertilizer, thermo-tolerant phosphate-solubilizing microbes including bacteria, actinomycetes, and fungi were isolated from different compost plants and biofertilizers. Except Streptomycesthermophilus J57 which lacked pectinase, all isolates possessed amylase, CMCase, chitinase, pectinase, protease, lipase, and nitrogenase activities. All isolates could solubilize calcium phosphate and Israel rock phosphate; various isolates could solubilize aluminum phosphate, iron phosphate, and hydroxyapatite. During composting, biofertilizers inoculated with the tested microbes had a significantly higher temperature, ash content, pH, total nitrogen, soluble phosphorus content, and germination rate than non-inoculated biofertilizer; total organic carbon and carbon-to-nitrogen ratio showed the opposite pattern. Adding these microbes can shorten the period of maturity, improve the quality, increase the soluble phosphorus content, and enhance the populations of phosphate-solubilizing and proteolytic microbes in biofertilizers. Therefore, inoculating thermo-tolerant phosphate-solubilizing microbes into agricultural and animal wastes represents a practical strategy for preparing multi-functional biofertilizer.

  5. Evidence for the assimilation of ancient glacier organic carbon in a proglacial stream food web

    Science.gov (United States)

    Fellman, Jason; Hood, Eran; Raymond, Peter A.; Hudson, J.H.; Bozeman, Maura; Arimitsu, Mayumi L.

    2015-01-01

    We used natural abundance δ13C, δ15N, and Δ14C to compare trophic linkages between potential carbon sources (leaf litter, epilithic biofilm, and particulate organic matter) and consumers (aquatic macroinvertebrates and fish) in a nonglacial stream and two reaches of the heavily glaciated Herbert River. We tested the hypothesis that proglacial stream food webs are sustained by organic carbon released from glacial ecosystems. Carbon sources and consumers in the nonglacial stream had carbon isotope values that ranged from -30‰ to -25‰ for δ13C and from -14‰ to 53‰ for Δ14C reflecting a food web sustained mainly on contemporary primary production. In contrast, biofilm in the two glacial stream sites was highly Δ14C-depleted (-215‰ to 175‰) relative to the nonglacial stream consistent with the assimilation of ancient glacier organic carbon. IsoSource modeling showed that in upper Herbert River, macroinvertebrates (Δ14C = -171‰ to 22‰) and juvenile salmonids (Δ14C = −102‰ to 17‰) reflected a feeding history of both biofilm (~ 56%) and leaf litter (~ 40%). We estimate that in upper Herbert River on average 36% of the carbon incorporated into consumer biomass is derived from the glacier ecosystem. Thus, 14C-depleted glacial organic carbon was likely transferred to higher trophic levels through a feeding history of bacterial uptake of dissolved organic carbon and subsequent consumption of 14C-depleted biofilm by invertebrates and ultimately fish. Our findings show that the metazoan food web is sustained in part by glacial organic carbon such that future changes in glacial runoff could influence the stability and trophic structure of proglacial aquatic ecosystems.

  6. Quantifying the Stock of Soil Organic Carbon using Multiple ...

    African Journals Online (AJOL)

    The stepwise multiple regression model was employed to identify ecological variables that explained significant variation of carbon in fallow soils. Using fallow genealogical cycles of 1st, 2nd, 3rd, 4th and 5th generations, soil and vegetation variables from 30 sampling plots were collected and subjected to linear regression ...

  7. Porous graphitic materials obtained from carbonization of organic ...

    Indian Academy of Sciences (India)

    features such as pore diameter, hierarchical porous archi- tectures, surface ... bon xerogels seem to be promising candidates for liquid ... co-solvent to increase the solubility of furfural, whilst the .... 100 nm, thus Vt means the total volume of pores below c.a. ..... Wang Z, Zhang X, Liu X, Lv M, Yang K and Meng J 2011 Carbon.

  8. Soil organic carbon stability across a Mediterranean oak agroecosystem

    Science.gov (United States)

    Leslie M. Roche; James F. Chang; Johan Six; Anthony T. O' Geen; Kenneth W. Tate

    2015-01-01

    Rangelands are estimated to cover 30 to 50 percent of the world's land surface and have significant belowground carbon (C) storage potential. Given their geographical extent, many have suggested that even modest changes in C storage via management practices could alter the global C cycle, creating climate change mitigation opportunities. Our objective was to...

  9. Modeling equilibrium adsorption of organic micropollutants onto activated carbon

    KAUST Repository

    De Ridder, David J.

    2010-05-01

    Solute hydrophobicity, polarizability, aromaticity and the presence of H-bond donor/acceptor groups have been identified as important solute properties that affect the adsorption on activated carbon. However, the adsorption mechanisms related to these properties occur in parallel, and their respective dominance depends on the solute properties as well as carbon characteristics. In this paper, a model based on multivariate linear regression is described that was developed to predict equilibrium carbon loading on a specific activated carbon (F400) for solutes reflecting a wide range of solute properties. In order to improve prediction accuracy, groups (bins) of solutes with similar solute properties were defined and solute removals were predicted for each bin separately. With these individual linear models, coefficients of determination (R2) values ranging from 0.61 to 0.84 were obtained. With the mechanistic approach used in developing this predictive model, a strong relation with adsorption mechanisms is established, improving the interpretation and, ultimately, acceptance of the model. © 2010 Elsevier Ltd.

  10. Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated carbon dioxide

    Science.gov (United States)

    A major goal of climate change research is to understand whether and how terrestrial ecosystems can sequester more carbon to mitigate rising atmospheric carbon dioxide (CO2) levels. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric CO2 has been assumed to be a major mecha...

  11. Temperature dependence of the relationship between pCO2 and dissolved organic carbon in lakes

    KAUST Repository

    Pinho, L.

    2016-02-15

    The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for low-latitude lakes (< 33°), despite very broad ranges in both pCO2 and DOC levels. These results suggest substantial differences in the carbon cycling of low-latitude lakes, which must be considered when upscaling limnetic carbon cycling to global scales.

  12. Temperature dependence of the relationship between pCO2 and dissolved organic carbon in lakes

    KAUST Repository

    Pinho, L.; Duarte, Carlos M.; Marotta, H.; Enrich-Prast, A.

    2016-01-01

    The relationship between the partial pressure of carbon dioxide (pCO2) and dissolved organic carbon (DOC) concentration in Brazilian lakes, encompassing 225 samples across a wide latitudinal range in the tropics, was tested. Unlike the positive relationship reported for lake waters, which was largely based on temperate lakes, we found no significant relationship for low-latitude lakes (< 33°), despite very broad ranges in both pCO2 and DOC levels. These results suggest substantial differences in the carbon cycling of low-latitude lakes, which must be considered when upscaling limnetic carbon cycling to global scales.

  13. The synthesis and characterization of tributyl phosphate grafted carbon nano-tubes by the floating catalytic chemical vapor deposition method and their sorption behavior towards uranium

    International Nuclear Information System (INIS)

    Shruti Mishra; Jaya Dwivedi; Amar Kumar; Nalini Sankararamakrishnan

    2016-01-01

    Carbon nano-tubes (CNTs) were synthesized by the floating catalytic chemical vapor deposition technique using ferrocene in benzene as the hydrocarbon source. The functionalization of CNTs was carried out by oxidation (CNT-OX) and grafting with a tributyl phosphate (TBP) ligand (CNT-TBP). Various spectroscopic techniques including scanning electron microscopy (SEM), Fourier Transform Infra Red Spectroscopy (FTIR), BET surface area and X-ray photoelectron spectroscopy (XPS) were used to characterize the adsorbents. FTIR and XPS studies revealed the efficient grafting of the TBP ligand on the CNT surface. The effect of the initial pH and the contact time for the maximum adsorption of U(VI) with CNT-plain, CNT-OX and CNT-TBP was studied. The spontaneity of the sorption was confirmed by thermodynamic data. A pseudo second order model with a regression coefficient of ≥0.978 was obtained for CNT-TBP and equilibrium was reached within 3 h. The Langmuir maximum adsorption capacity of U(VI) at pH 5 for CNT, CNT-OX and CNT-TBP was found to be 66.6, 100.0 and 166.6 mg.g -1 respectively. Using 0.1 M HCl as a de-sorbent, recyclability studies were carried out for three cycles. The probable mechanism of adsorption between U(VI) and CNT-TBP could be understood through FTIR and XPS techniques. (authors)

  14. Absorption features of chromophoric dissolved organic matter (CDOM) and tracing implication for dissolved organic carbon (DOC) in Changjiang Estuary, China

    OpenAIRE

    Zhang, X. Y.; Chen, X.; Deng, H.; Du, Y.; Jin, H. Y.

    2013-01-01

    Chromophoric dissolved organic matter (CDOM) represents the light absorbing fraction of dissolved organic carbon (DOC). Studies have shown that the optical properties of CDOM can be used to infer the distribution and diffusion characteristics of DOC in the estuary and coastal zone. The inversion of DOC concentrations from remote sensing has been implemented in certain regions. In this study we investigate the potential of tracing DOC from CDOM by the measure...

  15. Relationships between colored dissolved organic matter and dissolved organic carbon in different coastal gradients of the Baltic Sea

    OpenAIRE

    Harvey, E. Therese; Kratzer, Susanne; Andersson, Agneta

    2015-01-01

    Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coastal areas studied; the W Gulf of Bothnia with high terrestrial input and the NW Baltic Proper with ...

  16. Mapping soil organic carbon content and composition across Australia to assess vulnerability to climate change

    Science.gov (United States)

    Viscarra Rossel, R. A.

    2015-12-01

    We can effectively monitor soil condition—and develop sound policies to offset the emissions of greenhouse gases—only with accurate data from which to define baselines. Currently, estimates of soil organic C for countries or continents are either unavailable or largely uncertain because they are derived from sparse data, with large gaps over many areas of the Earth. Here, we derive spatially explicit estimates, and their uncertainty, of the distribution and stock of organic C content and composition in the soil of Australia. The composition of soil organic C may be characterized by chemical separation or physical fractionation based on either particle size or particle density (Skjemstad et al., 2004; Gregorich et al., 2006; Kelleher&Simpson, 2006; Zimmermann et al., 2007). In Australia, for example, Skjemstad et al. (2004) used physical separation of soil samples into 50-2000 and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, giving the three OC pools, particulate organic carbon (POC), humic organic carbon (HOC) and resistant organic carbon (ROC; charcoal or char-carbon). We assembled and harmonized data from several sources to produce the most comprehensive set of data on the current stock of organic C in soil of the continent. Using them, we have produced a fine spatial resolution baseline map of organic C, POC, HOC and ROC at the continental scale. In this presentation I will describe how we made the maps and how we use them to assess the vulnerability of soil organic C to for instance climate change.

  17. Assessing potential impacts of phosphate precipitation on nitrous oxide emissions and the carbon footprint of wastewater treatment plants.

    Science.gov (United States)

    Kosse, Pascal; Lübken, Manfred; Schmidt, Torsten C; Lange, Ruben-Laurids; Wichern, Marc

    2018-02-15

    Metal salts are widely used for the precipitation of phosphorus during wastewater treatment transforming soluble orthophosphate to an insoluble salt. In practice, more complex reactions are taking place including a reduction of the chemical solubility of dissolved greenhouse gases, such as nitrous oxide, present in the wastewater stream. In this respect, it was postulated that phosphorous precipitation will lead to artificial N 2 O stripping and hence to an increased carbon footprint of wastewater treatment plants. From lab-scale experiments utilizing N 2 O-saturated synthetic sewage solutions, it was evidenced that metal salt addition leads to N 2 O stripping with 20.8 g N 2 O per liter for a FeCl 2 -based precipitant to 26.4 g N 2 O per liter for a Al n (OH) m Cl3 n-m -based precipitant. Taking this maximum potential stripping effect into account for a carbon footprint analysis, a potential contribution of 16.11 kg CO 2,eq ·PE -1 ·a -1 was calculated in a case study, where FeCl 3 was considered. With respect to the defined system boundary conditions, the overall on-site and off-site CO 2 emissions were raised by 34% from 46.87 kg CO 2,eq ·PE -1 ·a -1 to 62.97 kg CO 2,eq ·PE -1 ·a -1 through CO 2,eq coming from phosphorous precipitation.

  18. A simple approach to estimate soil organic carbon and soil co/sub 2/ emission

    International Nuclear Information System (INIS)

    Abbas, F.

    2013-01-01

    SOC (Soil Organic Carbon) and soil CO/sub 2/ (Carbon Dioxide) emission are among the indicator of carbon sequestration and hence global climate change. Researchers in developed countries benefit from advance technologies to estimate C (Carbon) sequestration. However, access to the latest technologies has always been challenging in developing countries to conduct such estimates. This paper presents a simple and comprehensive approach for estimating SOC and soil CO/sub 2/ emission from arable- and forest soils. The approach includes various protocols that can be followed in laboratories of the research organizations or academic institutions equipped with basic research instruments and technology. The protocols involve soil sampling, sample analysis for selected properties, and the use of a worldwide tested Rothamsted carbon turnover model. With this approach, it is possible to quantify SOC and soil CO/sub 2/ emission over short- and long-term basis for global climate change assessment studies. (author)

  19. Climate Change Impacts on the Organic Carbon Cycle at the Land-Ocean Interface

    Science.gov (United States)

    Canuel, Elizabeth A.; Cammer, Sarah S.; McIntosh, Hadley A.; Pondell, Christina R.

    2012-05-01

    Estuaries are among the most altered and vulnerable marine ecosystems. These ecosystems will likely continue to deteriorate owing to increased population growth in coastal regions, expected temperature and precipitation changes associated with climate change, and their interaction with each other, leading to serious consequences for the ecological and societal services they provide. A key function of estuaries is the transfer, transformation, and burial of carbon and other biogenic elements exchanged between the land and ocean systems. Climate change has the potential to influence the carbon cycle through anticipated changes to organic matter production in estuaries and through the alteration of carbon transformation and export processes. This review discusses the effects of climate change on processes influencing the cycling of organic carbon in estuaries, including examples from three temperate estuaries in North America. Our goal is to evaluate the impact of climate change on the connectivity of terrestrial, estuarine, and coastal ocean carbon cycles.

  20. [Characteristics of organic carbon forms in the sediment of Wuliangsuhai and Daihai Lakes].

    Science.gov (United States)

    Mao, Hai-Fang; He, Jiang; Lü, Chang-Wei; Liang, Ying; Liu, Hua-Lin; Wang, Feng-Jiao

    2011-03-01

    The characteristics and differences of organic carbon forms in the sediments of the Wuliangsuhai and the Daihai Lakes with different eutrophication types were discussed in the present study. The results showed that the range of total organic carbon content (TOC) in Wuliangsuhai Lake was 4.50-22.83 g x kg(-1) with the average of 11.80 g x kg(-1). The range of heavy-fraction organic carbon content was 3.38-21.67 g x kg(-1) with the average of 10.76 g x kg(-1). The range of light-fraction organic carbon content was 0.46-1.80 g x kg(-1) with the average of 1.04 g x kg(-1); The range of ROC content was 0.62-3.64 g x kg(-1) with the average of 2.11 g x kg(-1), while the range of total organic carbon content in Daihai lake was 6.84-23.46 g x kg(-1) with the average of 14.94 g x kg(-1). The range of heavy-fraction organic carbon content was 5.27-22.23 g x kg(-1) with the average of 13.89 g x kg(-1). The range of light-fraction organic carbon content was 0.76-1.57 g x kg(-1). The range of ROC content was 1.54-7.08 g x kg(-1) with the average of 3.62 g x kg(-1). The results indicated that the heavy-fraction organic carbon was the major component of the organic carbon and plays an important role in the accumulation of organic carbon in the sediments of two Lakes. The content of light-fraction organic carbon was similar in the sediments of two lakes, whereas, the contents of total organic carbon and heavy-fraction organic carbon in the sediment of Wuliangsuhai Lake were less than those in the sediment of Daihai Lake, and the value of LFOC/TOC in the Wuliangsuhai Lake was larger than that in the Daihai Lake. The humin was the dominant component of the sediment humus, followed by fulvic acid in the two lakes. The values of HM/HS in the sediments of Wuliangsuhai lake range from 43.06% to 77.25% with the average of 62.15% and values of HM/HS in the sediments of Dahai lake range from 49.23% to 73.85% with the average of 65.30%. The tightly combined humus was the dominant form in

  1. Stable carbon isotope signals in particulate organic and inorganic carbon of coccolithophores - A numerical model study for Emiliania huxleyi.

    Science.gov (United States)

    Holtz, Lena-Maria; Wolf-Gladrow, Dieter; Thoms, Silke

    2017-05-07

    A recent numerical cell model, which explains observed light and carbonate system effects on particulate organic and inorganic carbon (POC and PIC) production rates under the assumption of internal pH homeostasis, is extended for stable carbon isotopes ( 12 C, 13 C). Aim of the present study is to mechanistically understand the stable carbon isotopic fractionation signal (ε) in POC and PIC and furthermore the vital effect(s) included in measured ε PIC values. The virtual cell is divided into four compartments, for each of which the 12 C as well as the 13 C carbonate system kinetics are implemented. The compartments are connected to each other via trans-membrane fluxes. In contrast to existing carbon fractionation models, the presented model calculates the disequilibrium state for both carbonate systems and for each compartment. It furthermore calculates POC and PIC production rates as well as ε POC and ε PIC as a function of given light conditions and the compositions of the external carbonate system. Measured POC and PIC production rates as well as ε PIC values are reproduced well by the model (comparison with literature data). The observed light effect on ε POC (increase of ε POC with increasing light intensities), however, is not reproduced by the basic model set-up, which is solely based on RubisCO fractionation. When extending the latter set-up by assuming that biological fractionation includes further carbon fractionation steps besides the one of RubisCO, the observed light effect on ε POC is also reproduced. By means of the extended model version, four different vital effects that superimpose each other in a real cell can be detected. Finally, we discuss potential limitations of the ε PIC proxy. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Assessing soil constituents and labile soil organic carbon by mid-infrared photoacoustic spectroscopy

    DEFF Research Database (Denmark)

    Peltre, Clément; Bruun, Sander; Du, Changwen

    2014-01-01

    ) degradability. The objective of this study was to assess the potential of FTIR-PAS for the characterisation of the labile fraction of SOC and more classical soil parameters, such as carbon and clay content, for a range of 36 soils collected from various field experiments in Denmark. Partial least squares (PLS...... signal. This also means that it should be advantageous for soil analysis because of its highly opaque nature. However, only a limited number of studies have so far applied FTIR-PAS to soil characterization and investigation is still required into its potential to determine soil organic carbon (SOC......) regression was used to correlate the collected FTIR-PAS spectra with the proportion of soil organic carbon mineralised after 238 days of incubation at 15°C and pF 2 (C238d) taken as an indicator of the labile fraction of SOC. Results showed that it is possible to predict total organic carbon content, total...

  3. A Raman Study of Carbonates and Organic Contents in Five CM Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Bodnar, R. J.; Farley, C.; Cheung, J. C. H.

    2016-01-01

    Carbonates comprise the second most abundant class of carbon-bearing phases in carbonaceous chondrites after organic matter (approximately 2 wt.%), followed by other C-bearing phases such as diamond, silicon carbide, and graphite. Therefore, understanding the abundances of carbonates and the associated organic matter provide critical insight into the genesis of major carbonaceous components in chondritic materials. Carbonates in CM chondrites mostly occur as calcite (of varying composition) and dolomite. Properly performed, Raman spectroscopy provides a non-destructive technique for characterizing meteorite mineralogy and organic chemistry. It is sensitive to many carbonaceous phases, allows the differentiation of organic from inorganic materials, and the interpretation of their spatial distribution. Here, with the use of Raman spectroscopy, we determine the structure of the insoluble organic matter (IOM) in the matrix and carbonate phases in five CM chondrites: Jbilet Winselwan, Murchison, Nogoya, Santa Cruz, and Wisconsin Range (WIS) 91600, and interpret the relative timing of carbonate precipitation and the extent of the associated alteration events.

  4. Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

    Directory of Open Access Journals (Sweden)

    R. R. Pawson

    2008-03-01

    Full Text Available This study investigates for the first time the relative importance of dissolved organic carbon (DOC and particulate organic carbon (POC in the fluvial carbon flux from an actively eroding peatland catchment in the southern Pennines, UK. Event scale variability in DOC and POC was examined and the annual flux of fluvial organic carbon was estimated for the catchment. At the event scale, both DOC and POC were found to increase with discharge, with event based POC export accounting for 95% of flux in only 8% of the time. On an annual cycle, exports of 35.14 t organic carbon (OC are estimated from the catchment, which represents an areal value of 92.47 g C m−2 a−1. POC was the most significant form of organic carbon export, accounting for 80% of the estimated flux. This suggests that more research is required on both the fate of POC and the rates of POC export in eroding peatland catchments.

  5. Adsorption of Volatile Organic Compounds from Aqueous Solution by Granular Activated Carbon in Batch System

    International Nuclear Information System (INIS)

    Zeinali, F.; Ghoreyshi, A. A.; Najafpour, G.

    2011-01-01

    Chlorinated hydrocarbons and aromatics are the major volatile organic compounds that contaminate the ground water and industrial waste waters. The best way to overcome this problem is to recover the dissolved compounds in water. In order to evaluate the potential ability of granular activated carbon for recovery of volatile organic compounds from water, the equilibrium adsorption was investigated. This study deals with the adsorption of dichloromethane as a typical chlorinated volatile organic compound and toluene as the representative of aromatic volatile organic compounds on a commercial granular activated carbon. The adsorption isotherms of these two volatile organic compounds on granular activated carbon were measured at thr