WorldWideScience

Sample records for carbonate phosphate organic

  1. Trehalose 6-phosphate coordinates organic and amino acid metabolism with carbon availability.

    Science.gov (United States)

    Figueroa, Carlos M; Feil, Regina; Ishihara, Hirofumi; Watanabe, Mutsumi; Kölling, Katharina; Krause, Ursula; Höhne, Melanie; Encke, Beatrice; Plaxton, William C; Zeeman, Samuel C; Li, Zhi; Schulze, Waltraud X; Hoefgen, Rainer; Stitt, Mark; Lunn, John E

    2016-02-01

    Trehalose 6-phosphate (Tre6P) is an essential signal metabolite in plants, linking growth and development to carbon metabolism. The sucrose-Tre6P nexus model postulates that Tre6P acts as both a signal and negative feedback regulator of sucrose levels. To test this model, short-term metabolic responses to induced increases in Tre6P levels were investigated in Arabidopsis thaliana plants expressing the Escherichia coli Tre6P synthase gene (otsA) under the control of an ethanol-inducible promoter. Increased Tre6P levels led to a transient decrease in sucrose content, post-translational activation of nitrate reductase and phosphoenolpyruvate carboxylase, and increased levels of organic and amino acids. Radio-isotope ((14)CO2) and stable isotope ((13)CO2) labelling experiments showed no change in the rates of photoassimilate export in plants with elevated Tre6P, but increased labelling of organic acids. We conclude that high Tre6P levels decrease sucrose levels by stimulating nitrate assimilation and anaplerotic synthesis of organic acids, thereby diverting photoassimilates away from sucrose to generate carbon skeletons and fixed nitrogen for amino acid synthesis. These results are consistent with the sucrose-Tre6P nexus model, and implicate Tre6P in coordinating carbon and nitrogen metabolism in plants. PMID:26714615

  2. The effect of induced anoxia and reoxygenation on benthic fluxes of organic carbon, phosphate, iron, and manganese.

    Science.gov (United States)

    Skoog, Annelie C; Arias-Esquivel, Victor A

    2009-11-15

    Eutrophication causes seasonally anoxic bottom waters in coastal environments, but we lack information on effects of onset of anoxia and subsequent reoxygenation on benthic fluxes of redox-sensitive minerals and associated organic carbon (OC). As the first study, we determined the effect of inducing anoxia and subsequently restoring oxic conditions in mesocosms with surface sediment and water from a coastal environment. These concentration changes were compared with those in an oxygenated control. We determined water column concentrations of dissolved organic carbon (DOC), particulate organic carbon (POC), iron, manganese, and phosphate. Benthic fluxes of DOC, POC, and iron increased at the onset of anoxia in oxygen-depleted treatments. DOC and iron concentrations increased concomitantly towards maxima, which may have indicated reductive dissolution of FeOOH and release of associated OC. The subsequent concomitant concentration decreases may have been the result of coprecipitation of OC with iron-containing minerals. In contrast, the phosphate-concentration increase occurred several days after the onset of anoxia and the manganese concentration was not affected by the onset of anoxia. Restoring oxic conditions resulted in a decrease in DOC, POC, and phosphate concentrations, which may indicate coprecipitation of OC with phosphate-containing minerals. The high DOC fluxes at the onset of anoxia indicate that redox oscillations may be important in OC degradation. Further, our results indicate a close coupling between OC cycling and dissolution/precipitation of iron-containing minerals in intermittently anoxic sediments.

  3. 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.

  4. Metal organic frameworks derived porous lithium iron phosphate with continuous nitrogen-doped carbon networks for lithium ion batteries

    Science.gov (United States)

    Liu, Yuanyuan; Gu, Junjie; Zhang, Jinli; Yu, Feng; Dong, Lutao; Nie, Ning; Li, Wei

    2016-02-01

    Lithium iron phosphate (LiFePO4) nanoparticles embedded in the continuous interconnected nitrogen-doped carbon networks (LFP/N-CNWs) is an optimal architecture to fast electron and Li+ conduction. This paper, for the first time, reports a reasonable design and successful preparation of porous hierarchical LFP/N-CNWs composites using unique Fe-based metal organic framework (MIL-100(Fe)) as both template and starting material of Fe and C. Such nitrogen-doped carbon networks (N-CNWs) surrounding the lithium iron phosphate nanoparticles facilitate the transfer of Li+ and electrons throughout the electrodes, which significantly decreases the internal resistance for the electrodes and results in the efficient utilization of LiFePO4. The synthesized LFP/N-CNWs composites possess a porous structure with an amazing surface area of 129 m2 g-1, considerably enhanced electrical conductivities of 7.58 × 10-2 S cm-1 and Li+ diffusion coefficient of 8.82 × 10-14 cm2 s-1, thereby delivering excellent discharge capacities of 161.5 and 93.6 mAh·g-1 at 0.1C and 20C, respectively.

  5. Organic Carbonates: Efficient Extraction Solvents for the Synthesis of HMF in Aqueous Media with Cerium Phosphates as Catalysts.

    Science.gov (United States)

    Dibenedetto, Angela; Aresta, Michele; di Bitonto, Luigi; Pastore, Carlo

    2016-01-01

    We describe a process for the selective conversion of C6 -polyols into 5-hydroxymethylfurfural (5-HMF) in biphasic systems of organic carbonate/water (OC/W), with cerium(IV) phosphates as catalysts. Different reaction parameters such as the OC/W ratio, catalyst loading, reaction time, and temperature, were investigated for the dehydration of fructose. Under the best reaction conditions, a yield of 67.7 % with a selectivity of 93.2 % was achieved at 423 K after 6 h of reaction using [(Ce(PO4)1.5 (H2 O)(H3 O)0.5 (H2 O)0.5)] as the catalyst. A maximum yield of 70 % with the same selectivity was achieved after 12 h. At the end of the reaction, the catalyst was removed by centrifugation, the organic phase was separated from water and evaporated in vacuo (with solvent recovery), and solid 5-HMF was isolated (purity >99 %). The recovery and reuse of the catalyst and the relationship between the structure of the OC and the efficiency of the extraction are discussed. The OC/W system influences the lifetime of the catalysts positively compared to only water.

  6. Organic Carbonates: Efficient Extraction Solvents for the Synthesis of HMF in Aqueous Media with Cerium Phosphates as Catalysts.

    Science.gov (United States)

    Dibenedetto, Angela; Aresta, Michele; di Bitonto, Luigi; Pastore, Carlo

    2016-01-01

    We describe a process for the selective conversion of C6 -polyols into 5-hydroxymethylfurfural (5-HMF) in biphasic systems of organic carbonate/water (OC/W), with cerium(IV) phosphates as catalysts. Different reaction parameters such as the OC/W ratio, catalyst loading, reaction time, and temperature, were investigated for the dehydration of fructose. Under the best reaction conditions, a yield of 67.7 % with a selectivity of 93.2 % was achieved at 423 K after 6 h of reaction using [(Ce(PO4)1.5 (H2 O)(H3 O)0.5 (H2 O)0.5)] as the catalyst. A maximum yield of 70 % with the same selectivity was achieved after 12 h. At the end of the reaction, the catalyst was removed by centrifugation, the organic phase was separated from water and evaporated in vacuo (with solvent recovery), and solid 5-HMF was isolated (purity >99 %). The recovery and reuse of the catalyst and the relationship between the structure of the OC and the efficiency of the extraction are discussed. The OC/W system influences the lifetime of the catalysts positively compared to only water. PMID:26676974

  7. Effect of natural dissolved organic carbon on phosphate removal by ferric chloride and aluminum sulfate treatment of wetland waters

    Science.gov (United States)

    Qualls, Robert G.; Sherwood, Lindsay J.; Richardson, Curtis J.

    2009-09-01

    The use of wetlands for the removal of excess N and P has become widespread. Some sensitive P-limited ecosystems, however, may require additional reductions in the concentration of P entering the system. It has been proposed that the treatment of wetlands through addition of ferric chloride or aluminum sulfate can augment the natural P removal mechanisms. However, high concentrations of natural dissolved organic matter may interfere with the removal of P by metal addition. We evaluated the doses of ferric chloride and aluminum sulfate necessary to reduce total P concentrations below 0.32 μM (10 μg/L) in water from the Northern Everglades, and we determined the effect of various concentrations (21, 38, and 60 mg/L) of natural dissolved organic carbon (DOC) on the removal of PO4 and total P. High concentrations of natural DOC inhibited both the short-term removal of PO4 and the longer-term removal of total P from the water column. Similar results were observed using 15 μM citric acid in an experiment to determine whether citric acid could effectively mimic the inhibition of phosphorus removal associated with natural DOC. Stoichiometry of these experiments indicates that the mechanism of natural DOC interference was not complexation of the metal ions by the DOC; we hypothesize that it could be adsorption to the terminal hydroxyl groups on a polynuclear Fe or Al colloid, effectively blocking the adsorption sites from a phosphate molecule. Also, the ability of citric acid to mimic the inhibitory effects also suggests that the results of the study are broadly applicable to wetland and other waters with high natural organic acid concentrations.

  8. The investigations of changes in mineral-organic and carbon-phosphate ratios in the mixed saliva by synchrotron infrared spectroscopy

    Science.gov (United States)

    Seredin, Pavel; Goloshchapov, Dmitry; Kashkarov, Vladimir; Ippolitov, Yuri; Bambery, Keith

    The objective of this study was to investigate the efficiency of the saturation of mixed saliva by mineral complexes and groups necessary for the remineralisation of tooth enamel using exogenous and endogenous methods of caries prevention. Using IR spectroscopy and high-intensity synchrotron radiation, changes in the composition of the human mixed saliva were identified when exogenous and endogenous methods of caries prevention are employed. Based on the calculations of mineral/organic and carbon/phosphate ratios, changes in the composition of the human mixed saliva depending on a certain type of prevention were identified. It is shown that the use of a toothpaste (exogenous prevention) alone based on a multi-mineral complex including calcium glycerophosphate provides only a short-term effect of saturating the oral cavity with mineral complexes and groups. Rinsing of the oral cavity with water following the preventive use of a toothpaste completely removes the effect of the saturation of the mixed saliva with mineral groups and complexes. The use of tablets of a multi-mineral complex with calcium glycerophosphate (endogenous prevention) in combination with exogenous prevention causes an average increase of ∼10% in the content of mineral groups and complexes in the mixed saliva and allows long-term saturation of the oral fluid by them. This method outperforms the exogenous one owing to a long-term effect of optimal concentrations of endogenous and biologically available derivatives of phosphates on the enamel surface.

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

    Institute of Scientific and Technical Information of China (English)

    XU Ren-kou; ZHU Yong-guan; David Chittleborough

    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 Iow-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 not correlated with PKa. Increase in the concentrations of organic acids enhanced P solubilization from both rock and iron phosphate almost linearrly. 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.

  10. NMR spectroscopic study of organic phosphate esters coprecipitated with calcite

    Science.gov (United States)

    Phillips, Brian L.; Zhang, Zelong; Kubista, Laura; Frisia, Silvia; Borsato, Andrea

    2016-06-01

    Organic phosphorus incorporated in calcite during laboratory precipitation experiments and in natural cave deposits was investigated by solid-state NMR spectroscopy. For calcite precipitated in the presence of organic phosphoesters of varying size and functionality, solid-state 31P{1H} CP/MAS NMR shows that the phosphoesters were incorporated intact into the solid. Systematic changes in the 31P NMR chemical shift of the phosphate group were observed between the solid phosphoester and that incorporated in the solid precipitate, yielding 31P NMR chemical shifts of the coprecipitates in the range of +1.8 to -2.2 ppm. These chemical shifts are distinct from that of similarly prepared calcite coprecipitated with inorganic phosphate, 3.5 ppm. Only minor changes were noted in the phosphoester 31P chemical shift anisotropy (CSA) which suggests no significant change in the local structure of the phosphate group, which is dominated by C-O-P bonding. Close spatial proximity of the organic phosphate group to calcite structural components was revealed by 31P/13C rotational echo double resonance (REDOR) experiments for coprecipitates prepared with 13C-labeled carbonate. All coprecipitates showed significant 31P dephasing effects upon 13C-irradiation, signaling atomic-scale proximity to carbonate carbon. The dephasing rate for smaller organophosphate molecules is similar to that observed for inorganic phosphate, whereas much slower dephasing was observed for larger molecules having long and/or bulky side-chains. This result suggests that small organic molecules can be tightly enclosed within the calcite structure, whereas significant structural disruption required to accommodate the larger organic molecules leads to longer phosphate-carbonate distances. Comparison of 31P NMR spectroscopic data from the synthetic coprecipitates with those from calcite moonmilk speleothems indicates that phosphorus occurs mainly as inorganic orthophosphate in the natural deposits, although small

  11. Interactions between organic amendments and phosphate fertilizers modify phosphate sorption processes in an acid soil

    Energy Technology Data Exchange (ETDEWEB)

    Sckefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, W.R. [Rutherglen Center, Rutherglen, Vic. (Australia)

    2008-07-15

    To determine how organic amendments and phosphate fertilizers interact to modify P sorption processes, three phosphate fertilizers were applied to lignite- and compost-amended acid soil and incubated for either 3 or 26 days. The fertilizers applied were potassium dihydrogen phosphate, triple superphosphate, and diammonium phosphate (DAP). After 3 days of incubation, sorption of all three P sources was decreased in the lignite-amended treatments, whereas P sorption was increased in the compost-amended treatments. Increased incubation time (26 days) resulted in significantly decreased P sorption when DAP was added to lignite-amended treatments. Addition of triple superphosphate increased P sorption in lignite- and compost-amended treatments and decreased solution pH compared with DAP application. In addition to the effect of P source, differences in P sorption between the lignite- and compost-amended treatments were driven by differences in solution chemistry, predominantly solution pH and cation dynamics. Soil amendment and fertilizer addition also increased microbial activity in the incubation systems, as measured by carbon dioxide respiration. It is proposed that the combination of lignite and DAP may contribute to decreased P sorption in acid soils, with the positive effects likely caused by both chemical and biological processes, including the formation of soluble organic-metal complexes.

  12. Soil Organic Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Soil organic carbon (SOC) is the carbon held within soil organic constituents (i.e., products produced as dead plants and animals decompose and the soil microbial...

  13. Carbon Mineralization Using Phosphate and Silicate Ions

    Science.gov (United States)

    Gokturk, H.

    2013-12-01

    Carbon dioxide (CO2) reduction from combustion of fossil fuels has become an urgent concern for the society due to marked increase in weather related natural disasters and other negative consequences of global warming. CO2 is a highly stable molecule which does not readily interact with other neutral molecules. However it is more responsive to ions due to charge versus quadrupole interaction [1-2]. Ions can be created by dissolving a salt in water and then aerosolizing the solution. This approach gives CO2 molecules a chance to interact with the hydrated salt ions over the large surface area of the aerosol. Ion containing aerosols exist in nature, an example being sea spray particles generated by breaking waves. Such particles contain singly and doubly charged salt ions including Na+, Cl-, Mg++ and SO4--. Depending on the proximity of CO2 to the ion, interaction energy can be significantly higher than the thermal energy of the aerosol. For example, an interaction energy of 0.6 eV is obtained with the sulfate (SO4--) ion when CO2 is the nearest neighbor [2]. In this research interaction between CO2 and ions which carry higher charges are investigated. The molecules selected for the study are triply charged phosphate (PO4---) ions and quadruply charged silicate (SiO4----) ions. Examples of salts which contain such molecules are potassium phosphate (K3PO4) and sodium orthosilicate (Na4SiO4). The research has been carried out with first principle quantum mechanical calculations using the Density Functional Theory method with B3LYP functional and Pople type basis sets augmented with polarization and diffuse functions. Atomic models consist of the selected ions surrounded by water and CO2 molecules. Similar to the results obtained with singly and doubly charged ions [1-2], phosphate and silicate ions attract CO2 molecules. Energy of interaction between the ion and CO2 is 1.6 eV for the phosphate ion and 3.3 eV for the silicate ion. Hence one can expect that the selected

  14. 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...

  15. Organic modification of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The organic modification of carbon nanotubes is a novel research field being developed recently. In this article, the history and newest progress of organic modification of carbon nanotubes are reviewed from two aspects:organic covalent modification and organic noncovalent modification of carbon nanotubes. The preparation and properties of organic modified carbon nanotubes are discussed in detail. In addition, the prospective development of organic modification of carbon nanotubes is suggested.

  16. Biomineralization of uraninite and uranyl phosphate controlled by organic acids

    International Nuclear Information System (INIS)

    Biomineralization of uraninite (UO2) and uranyl phosphate minerals are both able to decrease the mobility of uranium in the environment. We examined biomineralization of UO2 and uranyl phosphate by Shewanella putrefaciens in the basic medium containing lactate as an electron donor, β- glycerolphosphate as a phosphorous source, and uranyl nitrate in the absence and presence of weak or strong complexing organic acids (WCOA or SCOA) under an anaerobic condition. In the basic medium, only biomineralization of UO2 was observed because of rapid reduction of U(VI). Biomineralization of UO2 and uranyl phosphate occurred in the media with WCOA, however the no biomineralization was occurred in the presence of SCOA. It is thought that formation of stable U(VI)-, and U(IV)- organic complexes prevents the biomineralization. These finding suggest that coexisting organic acids control the biomineralization of UO2 and uranyl phosphate minerals by microorganisms. (author)

  17. Method of processing organic phosphate ester compound waste

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hiroshi; Nakamura, Shigetoshi; Nishimura, Kenji.

    1988-03-26

    Purpose: To convert organic solvent wastes mainly composed of organic phosphate esters into inorganic compounds, stabilize by solidification and apply volume-reduction treatment. Method: Hydrous aluminum chloride or aluminum polychloride is added to and mixed with organic solvent wastes containing organic phosphate esters as the main ingredient resulted from spent fuel reprocessings, by an amount of 0.3 or more mol per mol of the organic phosphate ester and then heated to solidify at a temperature from 50 to 150 deg C. Then, solidification products are sintered at a temperature higher than 270 deg C to remove alkyl group organic ingredients remained in the solidification products to convert them into stable inorganic phosphoric acid compounds. (Yoshino, Y.).

  18. 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

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

    International Nuclear Information System (INIS)

    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 32P-labeled phosphate and 14C-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)

  20. Analysis of phosphate-accumulating organisms cultivated under different carbon sources with polymerase chain reaction-denaturing gradient gel electrophoresis assay

    Institute of Scientific and Technical Information of China (English)

    YU Shui-li; LIU Ya-nan; JING Guo-lin; ZHAO Bing-jie; GUO Si-yuan

    2005-01-01

    To investigate the microbial communities of microorganisms cultivated under different carbon sources, three sequencing batch reactors were operated. They were supplied with sewage, glucose and sodium acetate as carbon sources respectively and showed high phosphorus removal performance. The results of denaturing gradient gel electrophoresis(DGGE) of polymerase chain reaction-amplified (PCR) 16S rDNA fragments demonstrated that β-protebacteria, Actinomyces sp. and γ-protebacteria only exited in 1 # reactor. The microbiological diversity of 1 # reactor exceeded the other two reactors. Flavobacterium, Bacillales, Actinomyces, Actinobacteridae and uncultured bacteria(AF527584, AF502204, AY592749, AB076862, AJ619051, AF495454 and AY133070) could be detected in the biological phosphorus removal reactors.

  1. ANTICORROSION PROPERTIES OF ORGANIC COATINGS CONTAINING POLYPHENYLENEDIAMINE PHOSPHATE

    OpenAIRE

    Miroslav Kohl; Andréa Kalendová

    2015-01-01

    The present work was aimed at the synthesis of polyphenylenediamine, its description and determination of parameters whose knowledge is required for the formulation of organic coatings pigmented with this compound. Polyphenylenediamine phosphate was prepared by oxidation polymerization in acidic environment. Phosphoric acid was used as the doping acid. Based on the results, pigmented organic coatings containing polyphenylenediamine at volume concentrations of 0%, 0.5%, 1%, 3%; 5%, and 10% wer...

  2. Total organic carbon analyzer

    Science.gov (United States)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  3. Nucleation of Fe-rich phosphates and carbonates on microbial cells and exopolymeric substances

    Directory of Open Access Journals (Sweden)

    Monica eSánchez-Román

    2015-09-01

    Full Text Available Although phosphate and carbonate are important constituents in ancient and modern environments, it is not yet clear their biogeochemical relationships and their mechanisms of formation. Microbially mediated carbonate formation has been widely studied whereas little is known about the formation of phosphate minerals. Here we report that a new bacterial strain, Tessarococcus lapidicaptus, isolated from the subsurface of Rio Tinto basin (Huelva, SW Spain, is capable of precipitating Fe-rich phosphate and carbonate minerals. We observed morphological differences between phosphate and carbonate, which may help us to recognize these minerals in terrestrial and extraterrestrial environments. Finally, considering the scarcity and the unequal distribution and preservation patterns of phosphate and carbonates, respectively, in the geological record and the biomineralization process that produces those minerals, we propose a hypothesis for the lack of Fe-phosphates in natural environments and ancient rocks.

  4. Carbon and Nitrogen Sources Influence Tricalcium Phosphate Solubilization and Extracellular Phosphatase Activity by Talaromyces flavus.

    Science.gov (United States)

    Stefanoni Rubio, P J; Godoy, M S; Della Mónica, I F; Pettinari, M J; Godeas, A M; Scervino, J M

    2016-01-01

    The aim of this work was to study phosphate (P) solubilization (and the processes involved in this event) by Talaromyces flavus (BAFC 3125) as a function of carbon and/or nitrogen sources. P solubilization was evaluated in NBRIP media supplemented with different carbon (glucose, sorbitol, sucrose, and fructose) and nitrogen (L-asparagine, urea, ammonium sulfate (AS), and ammonium nitrate (AN) combinations. The highest P solubilization was related to the highest organic acid production (especially gluconic acid) and pH drop for those treatments where glucose was present. Also P solubilization was higher when an inorganic nitrogen source was supplemented to the media when compared to an organic one. Although not being present an organic P source, phosphatase activity was observed. This shows that P mineralization and P solubilization can occur simultaneously, and that P mineralization is not induced by the enzyme substrate. The combination that showed highest P solubilization was for AN-glucose. The highest acid phosphatase activity was for AS-fructose, while for alkaline phosphatase were for AS-fructose and AN-fructose. Acid phosphatase activity was higher than alkaline. P solubilization and phosphatase activity (acid and alkaline) were influenced by the different carbon-nitrogen combinations. A better understanding of phosphate-solubilizing fungi could bring a better use of soil P.

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

    International Nuclear Information System (INIS)

    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

  6. ANTICORROSION PROPERTIES OF ORGANIC COATINGS CONTAINING POLYPHENYLENEDIAMINE PHOSPHATE

    Directory of Open Access Journals (Sweden)

    Miroslav Kohl

    2015-11-01

    Full Text Available The present work was aimed at the synthesis of polyphenylenediamine, its description and determination of parameters whose knowledge is required for the formulation of organic coatings pigmented with this compound. Polyphenylenediamine phosphate was prepared by oxidation polymerization in acidic environment. Phosphoric acid was used as the doping acid. Based on the results, pigmented organic coatings containing polyphenylenediamine at volume concentrations of 0%, 0.5%, 1%, 3%; 5%, and 10% were formed. The effect of the conductive polymer on the organic coatings‘ corrosion properties was examined via accelerated corrosion tests. From the results of an accelerated corrosion test it follows that if added to an epoxy-ester coating, this pigment improves appreciably the coating‘s corrosion resistance, especially at low pigment volume concentrations.

  7. 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.

  8. The flame photometric determination of calcium in phosphate, carbonate, and silicate rocks

    Science.gov (United States)

    Kramer, H.

    1957-01-01

    A flame photometric method of determining calcium in phosphate, carbonate, and silicate locks has been developed Aluminum and phosphate interference was overcome by the addition of a large excess of magnesium. The method is rapid and suitable for routine analysis Results obtained are within ?? 2% of the calcium oxide content. ?? 1957.

  9. The behaviour of tributyl phosphate in an organic diluent

    Science.gov (United States)

    Leay, Laura; Tucker, Kate; Del Regno, Annalaura; Schroeder, Sven L. M.; Sharrad, Clint A.; Masters, Andrew J.

    2014-09-01

    Tributyl phosphate (TBP) is used as a complexing agent in the Plutonium Uranium Extraction (PUREX) liquid-liquid phase extraction process for recovering uranium and plutonium from spent nuclear reactor fuel. Here, we address the molecular and microstructure of the organic phases involved in the extraction process, using molecular dynamics to show that when TBP is mixed with a paraffinic diluent, the TBP self-assembles into a bi-continuous phase. The underlying self-association of TBP is driven by intermolecular interaction between its polar groups, resulting in butyl moieties radiating out into the organic solvent. Simulation predicts a TBP diffusion constant that is anomalously low compared to what might normally be expected for its size; experimental nuclear magnetic resonance (NMR) studies also indicate an extremely low diffusion constant, consistent with a molecular aggregation model. Simulation of TBP at an oil/water interface shows the formation of a bilayer system at low TBP concentrations. At higher concentrations, a bulk bi-continuous structure is observed linking to this surface bilayer. We suggest that this structure may be intimately connected with the surprisingly rapid kinetics of the interfacial mass transport of uranium and plutonium from the aqueous to the organic phase in the PUREX process.

  10. Chemical immobilization of Pb, Cu, and Cd by phosphate materials and calcium carbonate in contaminated soils.

    Science.gov (United States)

    Huang, Guoyong; Su, Xiaojuan; Rizwan, Muhammad Shahid; Zhu, Yifei; Hu, Hongqing

    2016-08-01

    Soil contamination with toxic metals has increasingly become a global concern over the past few decades. Phosphate and carbonate compounds are good passivation materials for Pb immobilization, while the effect of phosphate and carbonate on the immobilization of multiple heavy metals (Pb, Cu, and Cd) in contaminated soils was seldom investigated. In this study, bone meal (BM), phosphate rock (PR), oxalic acid-activated phosphate rock (APR), super phosphate (SP), and calcium carbonate (CC) were added to the contaminated soils to evaluate the effect of phosphate materials and calcium carbonate on the immobilization of Pb, Cu, and Cd. The results showed that the pH of the treated soils increased 1.3-2.7, except SP which decreased 0.5 at most. Compared to the control treatment, all phosphates and calcium carbonate added to the polluted soils increased the fraction of residual metals, and the application of APR, PR, BM, and CC significantly reduced exchangeable and carbonate-bound fraction metals. PR and APR were the most effective for the immobilization of Pb, Cu, and Cd in the soils among these materials. Moreover, the concentrations of all metals in the toxicity characteristic leaching procedure (TCLP) leachate decreased with increasing amounts of amendments, and the concentrations of Pb in the TCLP leachate for soils treated with PR and APR were below the nonhazardous regulatory limit of 5 mg L(-1) (US Environmental Protection Agency). Based on our results, phosphate rock and oxalic acid-activated phosphate rock are effective in the immobilization of multiple metals by reducing their mobility in the co-contaminated soils. PMID:27197655

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

    Science.gov (United States)

    Tarayre, Cédric; Nguyen, Huu-Thanh; Brognaux, Alison; Delepierre, Anissa; De Clercq, Lies; Charlier, Raphaëlle; Michels, Evi; Meers, Erik; Delvigne, Frank

    2016-01-01

    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. PMID:27258275

  12. Initiation of Yeast Sporulation by Partial Carbon, Nitrogen, or Phosphate Deprivation

    OpenAIRE

    Freese, Elisabeth Bautz; Chu, Martha I.; Freese, Ernst

    1982-01-01

    In this paper we show that partial deprivation of a carbon source, a nitrogen source, or phosphate in the presence of all other nutrients needed for growth initiates meiosis and sporulation of Saccharomyces cerevisiae homothallic strain Y55. For carbon deprivation experiments, cells were grown in synthetic medium (pH 5.5) containing an excess of one carbon source and then transferred to the same medium containing different concentrations of the same carbon source. In the case of transfer to d...

  13. Calcification and Growth of the Marine Coccolithophorid Emiliania huxleyi in Response to Elevated Partial Pressure of Carbon Dioxide and Low Phosphate Conditions

    Science.gov (United States)

    Faber, D. N.; Fabry, V. J.; Dickson, A. G.

    2004-12-01

    Atmospheric carbon dioxide (CO2) is expected to reach about 780 ppm by the year 2100, under the IS92a business-as-usual scenario. This expected increase will give rise to more than a threefold increase in surface ocean CO2 concentration, cause a drop in surface seawater pH of 0.4 units, and decrease the carbonate ion concentration by 55%, relative to pre-industrial values. Previous work demonstrated that the coccolithophorid Emiliania huxleyi shows a marked decrease in calcification rates in response to elevated CO2 under nutrient-replete and nitrogen-limited conditions. Here we investigate the response of E. huxleyi to increased pCO2 under phosphate limitation. Results from laboratory and mesocosm experiments indicate that E. huxleyi can outcompete other phytoplankton in communities that are under phosphate control. Moreover, E. huxleyi has higher calcification rates under phosphate limitation, and model studies suggest that low phosphate levels are necessary for E. huxleyi to form dense blooms in the NE Atlantic. We grew E. huxleyi cells in 8-L closed systems under low phosphate conditions at present day and elevated pCO2 concentrations. Cell growth, particulate inorganic carbon, particulate organic carbon, total alkalinity and total dissolved inorganic carbon were measured over time. Results will be discussed in relation to predicted changes in the oceanic CO2/carbonate system.

  14. 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...

  15. 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.

  16. Soil organic carbon across scales.

    Science.gov (United States)

    O'Rourke, Sharon M; Angers, Denis A; Holden, Nicholas M; McBratney, Alex B

    2015-10-01

    Mechanistic understanding of scale effects is important for interpreting the processes that control the global carbon cycle. Greater attention should be given to scale in soil organic carbon (SOC) science so that we can devise better policy to protect/enhance existing SOC stocks and ensure sustainable use of soils. Global issues such as climate change require consideration of SOC stock changes at the global and biosphere scale, but human interaction occurs at the landscape scale, with consequences at the pedon, aggregate and particle scales. This review evaluates our understanding of SOC across all these scales in the context of the processes involved in SOC cycling at each scale and with emphasis on stabilizing SOC. Current synergy between science and policy is explored at each scale to determine how well each is represented in the management of SOC. An outline of how SOC might be integrated into a framework of soil security is examined. We conclude that SOC processes at the biosphere to biome scales are not well understood. Instead, SOC has come to be viewed as a large-scale pool subjects to carbon flux. Better understanding exists for SOC processes operating at the scales of the pedon, aggregate and particle. At the landscape scale, the influence of large- and small-scale processes has the greatest interaction and is exposed to the greatest modification through agricultural management. Policy implemented at regional or national scale tends to focus at the landscape scale without due consideration of the larger scale factors controlling SOC or the impacts of policy for SOC at the smaller SOC scales. What is required is a framework that can be integrated across a continuum of scales to optimize SOC management. PMID:25918852

  17. Organic acid production in vitro and plant growth promotion in maize under controlled environment by phosphate-solubilizing fluorescent Pseudomonas

    Directory of Open Access Journals (Sweden)

    Vyas Pratibha

    2009-08-01

    Full Text Available Abstract Background Phosphorus deficiency is a major constraint to crop production due to rapid binding of the applied phosphorus into fixed forms not available to the plants. Microbial solubilization of inorganic phosphates has been attributed mainly to the production of organic acids. Phosphate-solubilizing microorganisms enhance plant growth under conditions of poor phosphorus availability by solubilizing insoluble phosphates in the soil. This paper describes the production of organic acids during inorganic phosphate solubilization and influence on plant growth as a function of phosphate solubilization by fluorescent Pseudomonas. Results Nineteen phosphate-solubilizing fluorescent Pseudomonas strains of P. fluorescens, P. poae, P. trivialis, and Pseudomonas spp. produced gluconic acid, oxalic acid, 2-ketogluconic acid, lactic acid, succinic acid, formic acid, citric acid and malic acid in the culture filtrates during the solubilization of tricalcium phosphate, Mussoorie rock phosphate, Udaipur rock phosphate and North Carolina rock phosphate. The strains differed quantitatively and qualitatively in the production of organic acids during solubilization of phosphate substrates. Cluster analysis based on organic acid profiling revealed inter-species and intra-species variation in organic acids produced by Pseudomonas strains. The phosphate-solubilizing bacterial treatments P. trivialis BIHB 745, P. trivialis BIHB 747, Pseudomonas sp. BIHB 756 and P. poae BIHB 808 resulted in significantly higher or statistically at par growth and total N, P and K content over single super phosphate treatment in maize. These treatments also significantly affected pH, organic matter, and N, P, and K content of the soil. Conclusion The results implied that organic acid production by Pseudomonas strains is independent of their genetic relatedness and each strain has its own ability of producing organic acids during the solubilization of inorganic phosphates

  18. The effect of carbon on phosphate reduction. [in lunar soil and breccia metal particles

    Science.gov (United States)

    Friel, J. J.; Goldstein, J. I.; Romig, A. D., Jr.

    1977-01-01

    Several experiments were performed in order to evaluate the effect of carbon on phosphate reduction in synthetic systems. It was attempted to simulate in the experiments conditions occurring during lunar impact processes, but without shock pressure. Temperature, oxygen fugacity, and bulk chemistry were evaluated separately in order to determine the conditions which are suitable for carbon reduction. It appears on the basis of the results of the reported investigation that carbon can be an effective reducing agent during reheating events such as those encountered by lunar soils and breccias. Phosphate reduction may be viewed as a two-step process in which carbon is mobilized as CO during heating and preferentially dissolved in the metal phase. It then acts as a reducing agent on cooling. Gas phase transport and diffusion of carbon in metal are sufficiently rapid to allow uniform carbon distribution both within and between metal grains. The availability of metal from meteorites and carbon from the solar wind is probably sufficient to make reduction by carbon a significant process on the lunar surface.

  19. Dynamics models of soil organic carbon

    Institute of Scientific and Technical Information of China (English)

    YANGLi-xia; PANJian-jun

    2003-01-01

    As the largest pool of terrestrial organic carbon, soils interact strongly with atmosphere composition, climate, and land change. Soil organic carbon dynamics in ecosystem plays a great role in global carbon cycle and global change. With development of mathematical models that simulate changes in soil organic carbon, there have been considerable advances in understanding soil organic carbon dynamics. This paper mainly reviewed the composition of soil organic matter and its influenced factors, and recommended some soil organic matter models worldwide. Based on the analyses of the developed results at home and abroad, it is suggested that future soil organic matter models should be developed toward based-process models, and not always empirical ones. The models are able to reveal their interaction between soil carbon systems, climate and land cover by technique and methods of GIS (Geographical Information System) and RS (Remote Sensing). These models should be developed at a global scale, in dynamically describing the spatial and temporal changes of soil organic matter cycle. Meanwhile, the further researches on models should be strengthen for providing theory basis and foundation in making policy of green house gas emission in China.

  20. Reactivity of basic zirconium sulfate during interaction with carbonate, oxalate and phosphate reagents

    International Nuclear Information System (INIS)

    Methods of potentiometry and chemical analysis are used to study basic zirconium sulfate (BZS) interaction with carbonate (Na2CO3, NaHCO3), phosphate (Na3PO4, Na2HPO4, NaH2PO4, H3PO4) and oxalate ((NH4)2C2O4xH2O) reagents. Depending on conditions two different BZS - BZS-1 and BZS-2 are obtained. It is shown that BZS reactivity is defined by the possibility of substitution of oxo- and hydroxoligands and is decreased by increase of its deposition temperature. BZS-1 interaction with carbonate and oxalate reagents takes place at 25 deg C without changing basicity, and with phosphate reagents with basicity decrease up to formation of monophosphate which basicity is about 20%. During BZC-2 interaction oxo- and hydroxo-groups may be completely substituted for acidoligands with formation of nonhydrolysed compounds

  1. Influence of surface treatment of carbon fibers on electrochemical crystallization of calcium phosphate

    Institute of Scientific and Technical Information of China (English)

    TAO Ke; HUANG Su-ping; ZHOU Ke-chao

    2005-01-01

    Electrodeposition technique was used to coat calcium phosphate on carbon fiber which can be used to reinforce hydroxyapatite. The differences between fibers treated with and without nitric acid in electrodeposition were evaluated. The X-ray diffractometry results show that CaHPO4·2H2O is obtained as the kind of calcium phosphate coating on carbon fiber. The scanning electron microscopy photographs and deposit kinetic curve indicate that the influences of the functional group attained by nitric acid treatment, the crystal morphology and crystallization of the coating layers on the fiber with and without treatment rate are obviously different. The functional group, especially the acidic group, can act as nucleation centers of electrochemical crystallization.

  2. Model protocells photochemically reduce carbonate to organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Folsome, C.; Brittain, A.

    1981-06-11

    Synthetic cell-sized organic microstructures effect the long-wavelength uv photosynthesis of organic products from carbonate. Formaldehyde is the most abundant photoproduct and water is the major proton donor for this reduced form of carbon. We show here that these results for model phase-bounded systems are consistent with the postulate that metabolism of progenitors to the earliest living cells could have been, at least in part, photosynthetic.

  3. Lanthanum carbonate vs conventional phosphate binders for the treatment of hyperphosphatemia in maintenance hemodialysis patients: a meta-analysis

    Institute of Scientific and Technical Information of China (English)

    张晓娟

    2013-01-01

    Objective To assess the effect and safety of lanthanum carbonate vs conventional phosphate binders for hyperphosphatemia in patients undergoing maintenance hemodialysis.Methods According to the collaborative search strategy,MEDLINE (1996 to 2012.12) ,EBCO

  4. Magnesium carbonate for phosphate control in patients on hemodialysis. A randomized controlled trial

    OpenAIRE

    Tzanakis, Ioannis P.; Papadaki, Antonia N.; Wei, Mingxin; Kagia, Stella; Spadidakis, Vlassios V.; Kallivretakis, Nikolaos E.; Oreopoulos, Dimitrios G

    2008-01-01

    Background Magnesium salts bind dietary phosphorus, but their use in renal patients is limited due to their potential for causing side effects. The aim of this study was to evaluate the efficacy and safety of magnesium carbonate (MgCO3) as a phosphate-binder in hemodialysis patients. Methods Forty-six stable hemodialysis patients were randomly allocated to receive either MgCO3 (n = 25) or calcium carbonate (CaCO3), (n = 21) for 6 months. The concentration of Mg in the dialysate bath was 0.30 ...

  5. Effects of organic carbon sequestration strategies on soil enzymatic activities

    Science.gov (United States)

    Puglisi, E.; Suciu, N.; Botteri, L.; Ferrari, T.; Coppolecchia, D.; Trevisan, M.; Piccolo, A.

    2009-04-01

    Greenhouse gases emissions can be counterbalanced with proper agronomical strategies aimed at sequestering carbon in soils. These strategies must be tested not only for their ability in reducing carbon dioxide emissions, but also for their impact on soil quality: enzymatic activities are related to main soil ecological quality, and can be used as early and sensitive indicators of alteration events. Three different strategies for soil carbon sequestration were studied: minimum tillage, protection of biodegradable organic fraction by compost amendment and oxidative polimerization of soil organic matter catalyzed by biometic porfirins. All strategies were compared with a traditional agricultural management based on tillage and mineral fertilization. Experiments were carried out in three Italian soils from different pedo-climatic regions located respectively in Piacenza, Turin and Naples and cultivated with maize or wheat. Soil samples were taken for three consecutive years after harvest and analyzed for their content in phosphates, ß-glucosidase, urease and invertase. An alteration index based on these enzymatic activities levels was applied as well. The biomimetic porfirin application didn't cause changes in enzymatic activities compared to the control at any treatment or location. Enzymatic activities were generally higher in the minimum tillage and compost treatment, while differences between location and date of samplings were limited. Application of the soil alteration index based on enzymatic activities showed that soils treated with compost or subjected to minimum tillage generally have a higher biological quality. The work confirms the environmental sustainability of the carbon sequestering agronomical practices studied.

  6. 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.

  7. Organic solvent regeneration of granular activated carbon

    Science.gov (United States)

    Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

    1982-09-01

    The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

  8. Effect of Nutrient/Carbon Supplements on Biological Phosphate and Nitrate Uptake by Protozoan Isolates

    Science.gov (United States)

    Akpor, O. B.; Momba, M. N. B.; Okonkwo, J.

    This study was aimed at investigating the effect of nine different nutrient/carbon supplements in mixed liquor on nutrient uptake ability of three wastewater protozoan isolates, which have previously been screened for phosphate and nitrate uptake efficiency. The results revealed that over 50% of phosphate was removed in the presence of sodium acetate, glucose or sucrose. Similarly, nitrate uptake of over 60% was observed in the presence of sodium acetate, sodium succinate, glucose or sucrose. These trends were common in all the isolates. Chemical Oxygen Demand (COD) removal in the mixed liquor was only found to be significantly removed in mixed liquors that were supplemented with glucose, sucrose or sodium succinate. In the presence of sodium acetate, COD was observed to increase. The findings of this investigation have revealed that nutrient uptake and COD removal by the test protozoan isolates may be dependent primarily on the initial nutrient supplement in mixed liquor.

  9. Atomic layer deposition of amorphous iron phosphates on carbon nanotubes as cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    A non-aqueous approach was developed to synthesize iron phosphate cathode materials by the atomic layer deposition (ALD) technique. Deposition of iron phosphate thin films was achieved on nitrogen-doped carbon nanotubes (NCNTs) by combining ALD subcycles of Fe2O3 (ferrocene-ozone) and POx (trimethyl phosphate-water) at 200 – 350 °C. The thickness of iron phosphate thin films depends linearly on the ALD cycle, indicating their self-limiting growth behavior. The growth per cycle of iron phosphate thin films was determined to be ∼ 0.2, 0.4, 0.6, and 0.5 Å, at 200, 250, 300, and 350 °C, respectively. Characterization by SEM, TEM, and HRTEM techniques revealed uniform and conformal coating of amorphous iron phosphates on the surface of NCNTs. XANES analysis confirmed Fe−O−P bonding in the iron phosphates prepared by ALD. Furthermore, electrochemical measurement verified the high electrochemical activity of the amorphous iron phosphate as a cathode material in lithium-ion batteries. It is expected that the amorphous iron phosphate prepared by this facile and cost-effective ALD approach will find applications in the next generation of lithium-ion batteries and thin film batteries as either cathode materials or surface coating materials

  10. Calcium Carbonate versus Sevelamer Hydrochloride as Phosphate Binders after Long-Term Disease Progression in 5/6 Nephrectomized Rats

    Directory of Open Access Journals (Sweden)

    Suvi Törmänen

    2014-01-01

    Full Text Available Our aim was to compare the effects of calcium carbonate and sevelamer-HCl treatments on calcium-phosphate metabolism and renal function in 5/6 nephrectomized (NX rats so that long-term disease progression preceded the treatment. After 15-week progression, calcium carbonate (3.0%, sevelamer-HCl (3.0%, or control diets (0.3% calcium were given for 9 weeks. Subtotal nephrectomy reduced creatinine clearance (−40%, plasma calcidiol (−25%, and calcitriol (−70% and increased phosphate (+37%, parathyroid hormone (PTH (11-fold, and fibroblast growth factor-23 (FGF-23 (4-fold. In NX rats, calcium carbonate diet increased plasma (+20% and urinary calcium (6-fold, reduced plasma phosphate (−50% and calcidiol (−30%, decreased creatinine clearance (−35% and FGF 23 (−85%, and suppressed PTH without influencing blood pH. In NX rats, sevelamer-HCl increased urinary calcium (4-fold and decreased creatinine clearance (−45%, PTH (−75%, blood pH (by 0.20 units, plasma calcidiol (−40%, and calcitriol (−65%. Plasma phosphate and FGF-23 were unchanged. In conclusion, when initiated after long-term progression of experimental renal insufficiency, calcium carbonate diet reduced plasma phosphate and FGF-23 while sevelamer-HCl did not. The former induced hypercalcemia, the latter induced acidosis, while both treatments reduced vitamin D metabolites and deteriorated renal function. Thus, delayed initiation influences the effects of these phosphate binders in remnant kidney rats.

  11. Organic carbon biostimulates rapid rhizodegradation of perchlorate.

    Science.gov (United States)

    Yifru, Dawit D; Nzengung, Valentine A

    2008-12-01

    Previous hydroponics and field studies identified phytodegradation and rhizodegradation as the two main mechanisms by which plants metabolize perchlorate. Plant uptake and phytodegradation of perchlorate is a slower and undesired process that poses ecological risks resulting from phytoaccumulation of some fraction of the perchlorate. Meanwhile, rhizodegradation is a more rapid and favored process involving perchlorate-degrading bacteria utilizing dissolved organic carbon (DOC) as a carbon and energy (electron) source to rapidly degrade perchlorate to innocuous chloride. In the present study, rhizodegradation of perchlorate by willow trees (Salix nigra) was biostimulated using electron sources obtained from natural and artificial carbon sources. In bioreactors provided with carbon sources as 500 mg/L DOC, 25 to 40 mg/L of initial perchlorate concentrations were removed to below the ion chromatography method detection limit of 2 microg/L in approximately 9 d. For planted controls provided with no electron donors, the time required for the complete removal of the same doses of perchlorate was up to 70 d. Enhancement of rhizodegradation by organic carbon reduced the phytoaccumulated fraction of perchlorate by an order of magnitude from approximately 430 to 20 mg/kg. The implication of the present study is that the high fraction uptake and phytoaccumulation of perchlorate in agricultural products and the recycling of perchlorate into the ecosystem can be significantly curtailed by supplying electron donors derived from organic carbon sources to the root zone of plants. PMID:18593217

  12. On organic soil carbon and CO2

    OpenAIRE

    Bohn, Hinrich L.

    2011-01-01

    Cultivation of virgin lands released about 150 times 1012 kg of carbon as CO2 to the atmosphere during the last 100 years, at rates of 1 to 2 times 1012 kg/yr. These rates exceeded the CO2 evolved from fossil fuel combustion until the mid-1960s. Soil organic carbon, in organic and mineral soils, may play a considerable role in the CO2 cycle and in controlling the CO2 concentration of the atmosphere.DOI: 10.1111/j.2153-3490.1978.tb00863.x

  13. 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

  14. Fertilization increases paddy soil organic carbon density

    Institute of Scientific and Technical Information of China (English)

    Shao-xian WANG; Xiao-jun LI; Xin-qiang LIANG; Qi-xiang LUO; Fang FAN; Ying-xu CHEN; Zu-zhang LI; Huo-xi SUN; Tian-fang DAI; Jun-nan WAN

    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.

  15. 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.

  16. 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 applicati

  17. Mg-Enriched Engineered Carbon from Lithium-Ion Battery Anode for Phosphate Removal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan; Guo, Xingming; Yao, Ying; Wu, Feng; Zhang, Cunzhong; Chen, Renjie; Lu, Jun; Amine, Khalil

    2016-02-10

    Three Mg-enriched engineered carbons (mesocarbon microbeads, MCMB) were produced from lithium-ion battery anode using concentrated nitric acid oxidization and magnesium nitrate pretreatment. The obtained 15%Mg-MCMB, 30%Mg-MCMB, and 40%Mg-MCMB have magnesium level of 10.19, 19.13, and 19.96%, respectively. FTIR spectrum shows the functional groups present on the oxidized MCMB including OH, C=O, C–H, and C–O. XRD, SEM-EDX, and XPS analyses show that nanoscale Mg(OH)2 and MgO particles were presented on the surface of the Mg-MCMB samples, which could serve as the main adsorption mechanism as to precipitate phosphate from aqueous solutions. The sorption experiments indicate that Mg modification dramatically promotes MCMB’s phosphate removal ability and phosphate removal rates reach as high as 95%. Thus, modification of the spent LIBs anode could provide a novel direction of preparing wastewater adsorbent and develop an innovative way to achieve sustainable development.

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

    Science.gov (United States)

    Yuan, Wei; Han, Gaoyi; Chang, Yunzhen; Li, Miaoyu; Xiao, Yaoming; Zhou, Haihan; Zhang, Ying; Li, Yanping

    2016-11-01

    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 H3PO4/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 NaH2PO4·2H2O 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.

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

    International Nuclear Information System (INIS)

    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. Soil Organic Carbon Storage in China

    Institute of Scientific and Technical Information of China (English)

    XIE Xian-Li; SUN Bo; ZHOU Hui-Zhen; LI An-Bo

    2004-01-01

    Soil organic carbon (SOC) storage under different types of vegetations in China were estimated using measured data of 2 440 soil profiles to compare SOC density distribution between different estimates, to map the soil organic carbon stocks under different types of vegetation in China, and to analyze the relationships between soil organic carbon stocks and environmental variables using stepwise regression analyses. Soil organic carbon storage in China was estimated at 69.38 Gt (10 15 g). There was a big difference in SOC densities for various vegetation types, with SOC distribution closely related to climatic patterns in general. Stepwise regression analyses of SOC against environmental variables showed that SOC generally increased with increasing precipitation and elevation, while it decreased with increasing temperature.Furthermore, the important factor controlling SOC accumulation for forests was elevation, while for temperate steppes mean annual temperature dominated. The more specific the vegetation type used in the regression analysis, the greater was the effect of environmental variables on SOC. However, compared to native vegetation, cultivation activities in the croplands reduced the influence of environmental variables on SOC.

  1. Synthesis of lithium iron phosphate/carbon microspheres by using polyacrylic acid coated iron phosphate nanoparticles derived from iron(III) acrylate.

    Science.gov (United States)

    Xu, Dongwei; He, Yan-Bing; Chu, Xiaodong; Ding, Zhaojun; Li, Baohua; He, Jianfu; Du, Hongda; Qin, Xianying; Kang, Feiyu

    2015-03-01

    Lithium iron phosphate/carbon (LiFePO4 /C) microspheres with high rate and cycling performance are synthesized from iron phosphate/polyacrylic acid (FePO4 /PAA) nanoparticles. Iron(III) acrylate is used as a precursor for both the iron and carbon sources. FePO4 nanoparticles are first produced by a coprecipitation reaction. The byproduct, acrylic acid ions, is polymerized in situ to form a uniform PAA layer on the surface of the FePO4 nanoparticles. The as-prepared LiFePO4 /C microspheres are composed of primary nanoparticles with sizes of 40-50 nm. The nanoparticles are fully coated with a thin, uniform carbon layer derived from the decomposition of the PAA layer. The uniform carbon-coating layer cooperates with interstitial and boundary carbon derived from sucrose successfully to construct an excellent interconnecting conductive network in the microspheres. As a result of the unique structure, the as-prepared LiFePO4 /C microspheres display both high electronic and ionic conductivities, which contribute to their high rate performance (162.9 mAh g(-1) at 0.1C and 126.1 mAh g(-1) at 5C) and excellent cycling stability (97.1% of capacity retention after 500 cycles at 5C/5C).

  2. Hemolysis effect and calcium-phosphate precipitation of heat-organic-film treated magnesium

    Institute of Scientific and Technical Information of China (English)

    GAO Jia-cheng; QIAO Li-ying; LI Long-chuan; WANG Yong

    2006-01-01

    A heat-organic-films process was employed to induce calcium-phosphate apatites formation on magnesium, consequently the corrosion resistance and hemolysis properties of magnesium were improved for biomedical applications. Firstly, magnesium samples were heat-treated at 773 K for 10 h; secondly, stearic acid films were coated on the surface of the heat-treated magnesium.Then the surface modified magnesium was soaked in simulated body fluid (SBF) to test its corrosion resistance. The results show that the heat treatment process allows magnesium to form a dense oxide layer with a thickness of around 20 μm, thereby the surface modified magnesium has higher corrosion resistance. After 24 h in SBF island apatite was deposited on magnesium. The unevenly precipitates were characterized by XRD and FTIR as the mixture of hydroxyapatite(HA) and octacalcium phosphate(OCP). The preliminary hemolysis experiment indicates that untreated magnesium has hemolytic effect (about 60%); whereas the heat-organic film treated samples has no hemolytic effect. The mechanism of fast nucleation and growth of calcium-phosphate apatites on surface modified magnesium in SBF was also discussed.

  3. Organic amendment addition enhances phosphate fertiliser uptake and wheat growth in an acid soil

    Energy Technology Data Exchange (ETDEWEB)

    Schefe, C.R.; Patti, A.F.; Clune, T.S.; Jackson, W.R. [Rutherglen Centre, Rutherglen, Vic. (Australia). Dept. of Primary Industries

    2008-07-01

    The effect of 2 organic amendments (lignite and compost) on wheat growth and phosphate fertiliser efficiency (triple superphosphate, TSP; di-ammonium phosphate, DAP) in an acid soil was investigated in a glasshouse experiment. Organic amendments were incorporated into the top 40 mm of soil at rates resulting in a 1% and 2.5% increase in soil C, and fertilisers were banded within the seed row at rates equivalent to 5, 10, and 25 kg P/ ha. When no P was applied, addition of both organic amendments increased shoot height, with greatest growth recorded in the compost-amended treatments. Addition of organic amendments and P fertiliser resulted in additive effects, with increased shoot height, tiller number, and shoot dry matter (DM) in both the lignite-and compost-amended soils with fertiliser addition. The addition of 1% C resulted in plant growth equal to that measured at a higher rate of addition (2.5% C), resulting in a higher relative efficiency of application. Tissue P uptake was significantly increased when soil amendment was combined with 25 kg P/ ha DAP addition. Significant differences in nutrient uptake were also measured for other important plant nutrients. As the addition of organic amendments resulted in increased DM compared with untreated soil per unit of P fertiliser applied, it is feasible that this growth response may translate into increased yield. However, further study is required to de. ne the agronomic and economic feasibility of broad-scale application of such amendments for production gains.

  4. The Quest for Organic Carbon on Mars

    Science.gov (United States)

    Eigenbrode, Jennifer

    2011-01-01

    We are entering an era of Mars exploration in which organic carbon detection, characterization, and structural identification will be key to addressing some of the outstanding science objectives of the Mars Exploration Program. Success of these missions will depend on technical, scientific, and strategic elements--all of which are strongly determined based on terrestrial experience and knowledge of organic matter formation, concentration, and preservation. Analog studies including Precambrian sediments, modern endolithic communities, and experiments help us fine-tune these approaches, but we also need to expect the unexpected. This presentation will provide perspective on the challenges of detecting organic carbon on Mars, how we may achieve such detections with the in situ instruments, such as the SAM (Science Analysis at Mars) instrument suite onboard Curiosity, the rover for the 2011 Mars Science Laboratory mission.

  5. Enhanced cathode performance of nano-sized lithium iron phosphate composite using polytetrafluoroethylene as carbon precursor

    Science.gov (United States)

    Avci, Ercan

    2014-12-01

    Herein we report a facile and efficient solid state synthesis of carbon coated lithium iron phosphate (LiFePO4/C) cathode material achieved through the pyrolysis of polytetrafluoroethylene (PTFE). The current investigation is comparatively analyzed with the results of the composites of LiFePO4/C (LFP/C) synthesized using polystyrene-block-polybutadiene (PS-b-PBD), polyethyhylene (PE) and sucrose as carbon precursors. The optimized LFP/CPTFE composite is synthesized at 700 °C using 10 wt.% PTFE. The composite exhibits remarkable improvement in capacity, cyclability and rate capability compared to those of LFP/C synthesized using (PS-b-PBD), PE and sucrose. The specific discharge capacities as high as 166 mA h g-1 (theoretical capacity: 170 mA h g-1) at 0.2 C and 114 mA h g-1 at 10 C rates were achieved with LFP/CPTFE. In addition, the composite exhibits a long-term cycling stability with the capacity loss of only 11.4% after 1000 cycles. PTFE shifts the size distribution of the composite to nanometer scale (approximately 120 nm), however the addition of sucrose and other polymers do not have such an effect. According to TEM and XPS analysis, LFP/CPTFE particles are mostly coated with a few nanometers thick carbon layer forming a core-shell structure. Residual carbon does not contain fluorine.

  6. Coastal climate reflected in carbon-13/carbon-12 ratio of organic carbon in varved sediment from Santa Barbara basin

    OpenAIRE

    Schimmelmann, Arndt; Tegner, Mia J.

    1991-01-01

    A 1844-1987 time-series of carbon stable isotope ratios from dated sedimentary total organic carbon from the center of the Santa Barbara basin is compared with historical climate and oceanographic records. Carbon derived from carbon-13-depleted phytoplankton and carbon-13-enriched kelp appear responsible for a large part of the isotopic variance in sedimentary total organic carbon. El Niño/Southern Oscillation events are recorded by the isotopic response of marine organic carbon in sediments.

  7. Interactive effects of inorganic phosphate nutrition and carbon dioxide enrichment on assimilate partitioning in barley roots

    Energy Technology Data Exchange (ETDEWEB)

    Sicher, R.C. [Crops Systems and Global Change Lab., USDA, Agricultural Res. Service, beltsville, MD (United States)

    2005-02-01

    The combined effects of inorganic phosphate (Pi) insufficiency and CO{sub 2} enrichment on metabolite levels and carbon partitioning were studied using roots of 9-, 13- and 17-day-old barley seedlings (Hordeum vulgare L. cv. Brant). Plants were grown from seed in controlled environment chambers providing 36 {+-} 1 Pa (ambient) or 100 {+-} 2 Pa (elevated) CO{sub 2} and either 1.0 mM (Pi sufficient) or 0.05 mM (Pi insufficient) Pi. When values were combined for both Pi treatments, plants grown under enhanced CO{sub 2} showed increased root dry matter, adenylates (ATP + ADP), glutamine and non- structural carbohydrates other than starch. In contrast with shoots, enhanced CO{sub 2} partially reversed the inhibition of root dry matter formation imposed by Pi insufficiency. The Pi-insufficient treatment also increased sucrose, glucose and fructose levels in barley roots. The Pi and CO{sub 2} treatments were additive, so that the highest soluble carbohydrate levels were observed in roots of Pi-insufficient plants from the elevated CO{sub 2} treatment. Pi limitation decreased dry matter formation, acid-extractable Pi, nitrate, hexose-phosphates, glutamate, glutamine and acid invertase activity of barley roots in plants grown in both ambient and elevated CO{sub 2}. Adenylate levels in roots were unaffected by the moderate Pi insufficiency described here. Thus, the reduced hexose-phosphate levels of Pi-insufficient roots were not likely to be the result of low adenylate concentrations. The above results suggest that the capacity of barley roots to utilize carbohydrates from the shoot is inadequate under both Pi-insufficient and CO{sub 2}-enriched treatments. In addition, the Pi and CO{sub 2} treatments used here alter the nitrogen metabolism of barley roots. These findings further emphasize the importance of avoiding nutrient stress during CO{sub 2} enrichment experiments. (au)

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

    International Nuclear Information System (INIS)

    Either vitamin D3 (or 1 α,25-(OH)2-D3) 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 D3-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 D3- 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 D3 - stimulated CaBP concentration, but only in the absence of HC. Some limited suggestion of an intestinal phosphoprotein sensitve to either vitamin D3 or HC was observed. (orig.)

  9. Mechanochemical-hydrothermal synthesis of calcium phosphate powders with coupled magnesium and carbonate substitution

    Science.gov (United States)

    Suchanek, Wojciech L.; Byrappa, Kullaiah; Shuk, Pavel; Riman, Richard E.; Janas, Victor F.; TenHuisen, Kevor S.

    2004-03-01

    Magnesium- and carbonate-substituted calcium phosphate powders (Mg-, CO 3-CaP) with various crystallinity levels were prepared at room temperature via a heterogeneous reaction between MgCO 3/Ca(OH) 2 powders and an (NH 4) 2HPO 4 solution using the mechanochemical-hydrothermal route. X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis were performed. It was determined that the powders containing both Mg 2+ and CO 32- ions were incorporated uniformly into an amorphous calcium phosphate phase while in contrast, the as-prepared powder free of these dopants was crystalline phase-pure, stoichiometric hydroxyapatite. Dynamic light scattering revealed that the average particle size of the room temperature Mg-, CO 3-CaP powders was in the range of 482 nm-700 nm with a specific surface area between 53 and 91 m 2/g. Scanning electron microscopy confirmed that the Mg-, CO 3-CaP powders consisted of agglomerates of equiaxed, ≈20-35 nm crystals.

  10. The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

    Science.gov (United States)

    Kramer, Henry

    1956-01-01

    A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

  11. Mini Total Organic Carbon Analyzer (miniTOCA) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Total Organic Carbon (TOC) analyzers function by converting (oxidizing) all organic compounds (contaminants) in the water sample to carbon dioxide gas (CO2), then...

  12. 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.

  13. Enzymatic ring-opening copolymerization of trimethylene carbonate and ethylene ethyl phosphate

    Institute of Scientific and Technical Information of China (English)

    冯俊; 卓仁禧; 贺枫

    2003-01-01

    Enzymatic ring-opening copolymerization of trimethylene carbonate (TMC) and ethylene ethyl phosphate (EEP) are performed in bulk at 100℃ using porcine pancreas lipase (PPL) or candida rugosa lipase (CL) as catalyst. The factors affecting the yield and molecular weights such as catalyst concentration, polymerization time and monomer feed ratio are investigated. The random copolymers obtained have molecular weight ranging from 3200 to 10200. The glass transition temperature (Tg) of the copolymers decreases from 28 to 41.7℃, with the increase of the EEP content in the feed from zero to 5∶10. Degradation tests show that the degradability of the copolymers is improved by introduction of the EEP unit into the copolymer chain.

  14. Dispersion and separation of nanostructured carbon in organic solvents

    Science.gov (United States)

    Landi, Brian J. (Inventor); Raffaelle, Ryne P. (Inventor); Ruf, Herbert J. (Inventor); Evans, Christopher M. (Inventor)

    2011-01-01

    The present invention relates to dispersions of nanostructured carbon in organic solvents containing alkyl amide compounds and/or diamide compounds. The invention also relates to methods of dispersing nanostructured carbon in organic solvents and methods of mobilizing nanostructured carbon. Also disclosed are methods of determining the purity of nanostructured carbon.

  15. Stable Isotope Analyses of Phosphate Oxygen From Micro-samples of Biological Apatite: A new Routine Procedure for Silverphosphate Micro-precipitation and the Removal of Organic Contamination

    Science.gov (United States)

    Wiedemann-Bidlack, F. B.; Colman, A. S.; Fogel, M. L.

    2003-12-01

    Oxygen isotope analyses in bone and teeth of living and fossil animals are widely used for testing hypotheses about variability of diet and habitat. For the analysis of environmental or dietary changes in the past, tooth enamel has become the preferred study material, because its mineral content is higher than bone and dentine, and the relatively large size of the carbonato-apatite crystals of enamel make it more stable against post mortem diagenetic alteration than dentine or bone. Intra-tooth sampling of dental enamel is increasingly used for the investigation of seasonal climate variability, taking advantage of both the high correlation between an animal's drinking water and the δ 18O in its mineralized tissues and the incremental growth pattern of tooth enamel. The different oxygen-containing ions of bioapatite (phosphate, carbonate, and hydroxyl group) incorporate into the mineral lattice at different rates during enamel mineralization, and differ in their susceptibility against post mortem diagenetic alteration. In addition, it is difficult to account for the different reaction chemistries of phosphate, carbonate, and hydroxyl group using isotope analysis techniques that include all oxygen contained in the enamel (e.g., laser ablation). These problems can be addressed analyzing phosphate oxygen only. However, two major factors limit the potential of δ 18O analyses in dental enamel: A) the starting sample size for isotope analyzes often precludes the use of small teeth or the intra-tooth sampling of a given tooth; B) Small amounts of biogenic organic material in tooth enamel (less than 1% by wt) can reduce the precision and lead to anomalous analytical results in δ 18O measurements on Ag3PO4 produced from tooth enamel. A new procedure was developed for the pre-treatment and δ 18O analysis of phosphate from small samples (500 μ g) of tooth enamel containing organic matter. Ag3PO{4} was precipitated quantitatively for analysis of δ 18Ophosphate using a

  16. 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.

  17. Urban tree effects on soil organic carbon.

    Science.gov (United States)

    Edmondson, Jill L; O'Sullivan, Odhran S; Inger, Richard; Potter, Jonathan; McHugh, Nicola; Gaston, Kevin J; Leake, Jonathan R

    2014-01-01

    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. PMID:25003872

  18. Biochar enhances Aspergillus niger rock phosphate solubilization by increasing organic acid production and alleviating fluoride toxicity.

    Science.gov (United States)

    Mendes, Gilberto de Oliveira; Zafra, David Lopez; Vassilev, Nikolay Bojkov; Silva, Ivo Ribeiro; Ribeiro, José Ivo; Costa, Maurício Dutra

    2014-05-01

    During fungal rock phosphate (RP) solubilization, a significant quantity of fluoride (F(-)) is released together with phosphorus (P), strongly inhibiting the process. In the present study, the effect of two F(-) adsorbents [activated alumina (Al2O3) and biochar] on RP solubilization by Aspergillus niger was examined. Al2O3 adsorbed part of the F(-) released but also adsorbed soluble P, which makes it inappropriate for microbial RP solubilization systems. In contrast, biochar adsorbed only F(-) while enhancing phosphate solubilization 3-fold, leading to the accumulation of up to 160 mg of P per liter. By comparing the values of F(-) measured in solution at the end of incubation and those from a predictive model, it was estimated that up to 19 mg of F(-) per liter can be removed from solution by biochar when added at 3 g liter(-1) to the culture medium. Thus, biochar acted as an F(-) sink during RP solubilization and led to an F(-) concentration in solution that was less inhibitory to the process. In the presence of biochar, A. niger produced larger amounts of citric, gluconic, and oxalic acids, whether RP was present or not. Our results show that biochar enhances RP solubilization through two interrelated processes: partial removal of the released F(-) and increased organic acid production. Given the importance of organic acids for P solubilization and that most of the RPs contain high concentrations of F(-), the proposed solubilization system offers an important technological improvement for the microbial production of soluble P fertilizers from RP.

  19. Methods development for total organic carbon accountability

    Science.gov (United States)

    Benson, Brian L.; Kilgore, Melvin V., Jr.

    1991-01-01

    This report describes the efforts completed during the contract period beginning November 1, 1990 and ending April 30, 1991. Samples of product hygiene and potable water from WRT 3A were supplied by NASA/MSFC prior to contract award on July 24, 1990. Humidity condensate samples were supplied on August 3, 1990. During the course of this contract chemical analyses were performed on these samples to qualitatively determine specific components comprising, the measured organic carbon concentration. In addition, these samples and known standard solutions were used to identify and develop methodology useful to future comprehensive characterization of similar samples. Standard analyses including pH, conductivity, and total organic carbon (TOC) were conducted. Colorimetric and enzyme linked assays for total protein, bile acid, B-hydroxybutyric acid, methylene blue active substances (MBAS), urea nitrogen, ammonia, and glucose were also performed. Gas chromatographic procedures for non-volatile fatty acids and EPA priority pollutants were also performed. Liquid chromatography was used to screen for non-volatile, water soluble compounds not amenable to GC techniques. Methods development efforts were initiated to separate and quantitate certain chemical classes not classically analyzed in water and wastewater samples. These included carbohydrates, organic acids, and amino acids. Finally, efforts were initiated to identify useful concentration techniques to enhance detection limits and recovery of non-volatile, water soluble compounds.

  20. 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.

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

    Directory of Open Access Journals (Sweden)

    Leandro M. Marra

    2015-06-01

    Full Text Available 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(PO42 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(PO42 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.

  2. Calculating Organic Carbon Stock from Forest Soils

    Directory of Open Access Journals (Sweden)

    Lucian Constantin DINCĂ

    2015-12-01

    Full Text Available The organic carbon stock (SOC (t/ha was calculated in different approaches in order to enhance the differences among methods and their utility regarding specific studies. Using data obtained in Romania (2000-2012 from 4,500 profiles and 9,523 soil horizons, the organic carbon stock was calculated for the main forest soils (18 types using three different methods: 1 on pedogenetical horizons, by soil bulk density and depth class/horizon thickness; 2 by soil type and standard depths; 3 using regression equations between the quantity of organic C and harvesting depths. Even though the same data were used, the differences between the values of C stock obtained from the three methods were relatively high. The first method led to an overvaluation of the C stock. The differences between methods 1 and 2 were high (and reached 33% for andosol, while the differences between methods 2 and 3 were smaller (a maximum of 23% for rendzic leptosol. The differences between methods 2 and 3 were significantly lower especially for andosol, arenosol and vertisol. A thorough analysis of all three methods concluded that the best method to evaluate the organic C stock was to distribute the obtained values on the following standard depths: 0 - 10 cm; 10 - 20 cm; 20 - 40 cm; > 40 cm. For each soil type, a correlation between the quantity of organic C and the sample harvesting depth was also established. These correlations were significant for all types of soil; however, lower correlation coefficients were registered for rendzic leptosol, haplic podzol and fluvisol.

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

    OpenAIRE

    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 of CaCl2 and NaHCO3 were mixed to achieve Ca/CO3 ratios of 1:1 and 10:1 at different pumping rates with and without phosphate. Results showed that, at pH 13.4, only ikaite wa...

  4. 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.

  5. Carbon and phosphorus exchange may enable cooperation between an arbuscular mycorrhizal fungus and a phosphate-solubilizing bacterium.

    Science.gov (United States)

    Zhang, Lin; Xu, Minggang; Liu, Yu; Zhang, Fusuo; Hodge, Angela; Feng, Gu

    2016-05-01

    Arbuscular mycorrhizal fungi (AMF) transfer plant photosynthate underground which can stimulate soil microbial growth. In this study, we examined whether there was a potential link between carbon (C) release from an AMF and phosphorus (P) availability via a phosphate-solubilizing bacterium (PSB). We investigated the outcome of the interaction between the AMF and the PSB by conducting a microcosm and two Petri plate experiments. An in vitro culture experiment was also conducted to determine the direct impact of AMF hyphal exudates on growth of the PSB. The AMF released substantial C to the environment, triggering PSB growth and activity. In return, the PSB enhanced mineralization of organic P, increasing P availability for the AMF. When soil available P was low, the PSB competed with the AMF for P, and its activity was not stimulated by the fungus. When additional P was added to increase soil available P, the PSB enhanced AMF hyphal growth, and PSB activity was also stimulated by the fungus. Our results suggest that an AMF and a free-living PSB interacted to the benefit of each other by providing the C or P that the other microorganism required, but these interactions depended upon background P availability. PMID:27074400

  6. 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.

  7. Study on the Dispersion of 1.5mm & 4mm Chopped Carbon Fiber in Triethyl Phosphate

    Directory of Open Access Journals (Sweden)

    Hu Rui

    2016-01-01

    Full Text Available For the preparation of chopped CF (carbon fiber, CF composite material, it must be scattered at first. Based on the theory of “direct observation” and “crowding factor”, 1.5 mm and 4 mm short cut dispersion of CF which is done by acetone firstly in triethyl phosphate was studied in this paper, using triethyl phosphate as dispersant. Controlling the dosage of the dispersant and ultrasonic time to prepare for the dispersion of suspension, the macroscopic and microscopic structure of CF were tested before and after treatment. Test results show that to achieve good dispersibility for 4mm and 1.5mm CF with mass of 0.1g, the ultrasonic time should be controlled 2h and the amount of triethyl phosphate, the quality is 0.1 g of 4 mm and 1.5 mm of CF good dispersibility, respectively is 200 ml and 300 ml of dispersion conditions.

  8. OCoc- from Ocean Colour to Organic Carbon

    Science.gov (United States)

    Heim, B.; Overduin, P. P.; Schirrmeister, L.; Lantuit, H.; Doerffer, R.

    2009-12-01

    Enhanced permafrost warming and increased arctic river discharges have heightened concern about the input of terrigenous matter into Arctic coastal waters. The ‘OCoc-from Ocean Colour to Organic Carbon’ project (IPY-project 1176), funded by the German Research Foundation (DFG), is an Ocean Colour study joined with the Arctic Coastal Dynamics ACD network and Arctic Circum-polar Coastal Observatory Network ACCO-Net (IPY-project 90). OCoc uses Ocean Colour satellite data for synoptical monitoring of organic matter fluxes from fluvial and coastal sources. Initial results from German-Russian expeditions at the southeastern Laptev Sea Coast (Arctic Siberia, Russia) in August 2008 and August 2009 are presented. Large parts of this coastal zone are characterized by highly erosive organic-rich material. Ocean Colour MERIS Reduced Resolution (RR)-LIB data of the have been processed towards optical aquatic parameters using Beam-Visat4.2 and the MERIS case2 regional processor for coastal application (C2R). Calculated aquatic parameters are absorption and backscattering coefficients, apparent optical properties such as the first attenuation depth (‘Z90’) and calculated concentrations of chlorophyll, total suspended matter and coloured dissolved organic matter absorption from the water leaving reflectances. Initial comparisons with expedition data (Secchi depths, cDOM) show that the MERIS-C2R optical parameters ’total absorption’ and the first attenuation depth, ’Z90’, seem adequately to represent true conditions. High attenuation values in the spectral blue wavelength range may serve as tracer for the organic-rich terrigenous input. The synoptic information of Ocean Colour products will provide valuable spatial and dynamical information on the Organic Carbon and sediment fluxes from the Siberian permafrost coast.

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

    OpenAIRE

    Cédric Tarayre; Huu-Thanh Nguyen; Alison Brognaux; Anissa Delepierre; Lies De Clercq; Raphaëlle Charlier; Evi Michels; Erik Meers; Frank Delvigne

    2016-01-01

    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 latte...

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

    OpenAIRE

    Tarayre, Cédric; Nguyen, Huu-Thanh; Brognaux, Alison; Delepierre, Anissa; De Clercq, Lies; Charlier, Raphaëlle; Michels, Evi; Meers, Erik; Delvigne, Frank

    2016-01-01

    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...

  11. Fate of Organic Micropollutants during Hydrothermal Carbonization

    Science.gov (United States)

    Weiner, B.; Baskyr, I.; Pörschmann, J.; Kopinke, F.-D.

    2012-04-01

    The hydrothermal carbonization (HTC) is an exothermic process, in which biomass in an aqueous suspension is transformed into a bituminous coal-like material (hydrochar) at temperatures between 180-250°C and under moderate pressure. With these process conditions, little gas is generated (1-5%), and a fraction of the organic carbon is dissolved in the aqueous phase (10-30%) but the largest part is obtained as solid char. The respective yields and the molecular composition depend on the choice of educts and the process conditions, such as temperature, pH-value, and reaction time. Various biomass-educts have recently been studied, such as waste materials from agriculture, brewer's spent grains, sewage sludge, as well as wood and paper materials. Besides their use for energy generation, the hydrochars have also been investigated as soil amendments. Prior to addition of the chars to soil, these should be free of toxic components that could be released into the environment as harmful organic pollutants. Herein, the potential for the degradation of trace organic pollutants, such as pesticides and pharmaceuticals, under typical HTC conditions will be presented. The degradation of selected organic pollutants with different polarity and hydrophobicity was investigated. Scope and limitations of the degradation potential of the HTC are discussed on examples of micro pollutants such as hormones, residues of pharmaceuticals and personal care products including their metabolites, and pesticides. We will show that the target analytes are partially and in some cases completely degraded. The degree of degradation depends on the HTC process conditions such as reaction temperature and time, the solution pH value, the presence of catalysts or additional reagents. The biotic and abiotic degradation of chlorinated organic compounds, in particular chlorinated aromatics, has been a well-known environmental problem and remains a challenging issue for the development of a HTC process for

  12. Organic Carbon Dynamics in Glacier Systems

    Science.gov (United States)

    Barker, J.; Sharp, M.; Klassen, J.; Foght, J.; Turner, R.

    2004-12-01

    The biogeochemical cycling of organic carbon (OC) has important implications for aquatic system ecology because the abundance and molecular characteristics of OC influence contaminant transport and bioavailability, and determine its suitability as a substrate for microbial metabolism. There have been few studies of OC cycling in glacier systems, and questions remain regarding the abundance, provenance, and biogeochemical transformations of OC in these environments. To address these questions, the abundance and molecular characteristics of OC is investigated in three glacier systems. These systems are characterized by different thermal and hydrological regimes and have different potential OC sources. John Evans Glacier is a polythermal glacier in arctic Canada. Outre Glacier is a temperate glacier in the Coast Mountains of British Columbia, Canada. Victoria Upper Glacier is a cold-based glacier in the McMurdo Dry Valleys of Antarctica. To provide an indication of the extent to which glacier system OC dynamics are microbially mediated, microbial culturing and identification is performed and organic acid abundance and speciation is determined. Where possible, samples of supraglacial runoff, glacier ice and basal ice and subglacial meltwater were collected. The dissolved organic carbon (DOC) concentration in each sample was measured by combustion/non-dispersive infrared gas analysis. Emission and synchronous fluorescence spectroscopy were used to characterize the molecular properties of the DOC from each environment. When possible, microbial culturing and identification was performed and organic acid identification and quantification was measured by ion chromatography. DOC exists in detectable quantities (0.06-46.6 ppm) in all of the glacier systems that were investigated. The molecular characteristics of DOC vary between glaciers, between environments at the same glacier, and over time within a single environment. Viable microbes are recoverable in significant (ca

  13. Isolation and characterization of biogenic calcium carbonate/phosphate from oral bacteria and their adhesion studies on YSZ-coated titanium substrate for dental implant application

    Indian Academy of Sciences (India)

    GOBI SARAVANAN KALIARAJ; KAMALAN KIRUBAHARAN; G PRADHABAN; P KUPPUSAMI; VINITA VISHWAKARMA

    2016-04-01

    Biogenic calcium carbonate/phosphate were isolated and characterized from oral bacteria (CPOB). The crystalline nature and morphology of calcium carbonate/phosphate were characterized by X-ray diffraction (XRD)and field emission scanning electron microscopy (FESEM), respectively. XRD analysis revealed the cubic phase of YSZ coating as well as biogenic calcium carbonate (rhombohedral) and calcium phosphate oxide (hexagonal) wasobserved from CPOB. FESEM confirmed the extracellular synthesis of calcium compounds. Bacterial adhesion result reveals that YSZ coating drastically reduce bacterial invasion than titanium substrate.

  14. Some Organic Reactions in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    JIANG Huan-feng; YANG Xiao-yue; LI Guo-ping; ZOU Gang

    2004-01-01

    Organic reactions in supercritical carbon dioxide (scCO2) have facilitated great progress in recent years 1. ScCO2, as an environmentally friendly reaction medium, may be a substitute for volatile and toxic organic solvents and show some special advantages. Firstly, CO2 is inexpensive,nonflammable, nontoxic and chemical inert under many conditions. Secondly, scCO2 possesses hybrid properties of both liquid and gas, to the advantage of some reactions involving gaseous reagents. Control of the solvent density by variation of the temperature and pressure enables the solvent properties to be "tuned" to reactants. Finally, separating of CO2 from the reaction mixture is energy-efficient and simple. Here we disclose our new work on some organic reactions involving small molecules in scCO2.The results showed that the upper reactions in scCO2 could be carried out smoothly and thepressure of CO2 had a remarkable effect on the conversion and selectivity.

  15. Effects of Organic Anions on Phosphate Adsorption and Desorption from Variable—Charge Clay Minerals and Soil

    Institute of Scientific and Technical Information of China (English)

    HEZHEN-LI; YUANKE-NENG; 等

    1992-01-01

    Effects of citrate and tartrate on phosphate adsorption and desorption from kaolinite,goethite,amorphous Al-oxide and Ultisol were studied.P adsorption was significantly decreased as the concentration of the organic anions increased from 10-5 to 10-1 M.At 0.1 M and pH 7.0,tartrate decreased P adsorption by 27.6%-50.6% and citrate by 37.9-80.4%,depending on the kinds of adsorbent.Little Al and/or Fe were detected in the equilibrium solutions,even at the highest concentration of the organic anions.Effects of the organic anions on phosphate adsorption follow essentially the competitive adsorption mechanism.The selectivity coefficients for competitive adsorption can be used to compare the effectiveness of different organic anions in reducing P adsorption under given gonditions. Phosphate desorption was increased by 3 to 100 times in the presence of 0.001 M citrate or tartrate compared to that in 0.02 M KCl solution alone.However,for all the soil and clay minerals studied the amount of P desorbed by citrate or tartrate was generally lower than or close to that of isotopically exchangeable P.The effect of organic anions on phosphate desorption arises primarily from ligand exchange.

  16. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis

    DEFF Research Database (Denmark)

    Bro, S; Rasmussen, R A; Handberg, J;

    1998-01-01

    into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium carbonate (US$6.00/d v US$0.65/d). Calcium ketoglutarate may be an effective and safe alternative to treatment with aluminum......The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main...... outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate...

  17. 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

    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). The sup......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...

  18. Organic acids inhibit the formation of pyromorphite and Zn-phosphate in phosphorous amended Pb- and Zn-contaminated soil.

    Science.gov (United States)

    Debela, F; Arocena, J M; Thring, R W; Whitcombe, T

    2013-02-15

    Pyromorphite (PY) and some zinc phosphates (Zn-P) are very sparingly soluble minerals and hence can immobilize Pb and Zn in contaminated soils. However, mechanisms leading to the poor efficiency of PY and Zn-P formation in contaminated soils amended with P still remain unclear. We studied the influence of two low molecular weight organic acids (LMWOA) - oxalic acid and citric acid and diethylene triamine pentaacetic acid (DTPA) - in PY and Zn-P formation in a P-amended contaminated soil. Despite the high levels of metals (∼4% Pb and 21% Zn) in the study soil, the addition of up to 1% inorganic P transformed only up to 37% and 17% of the total Pb and Zn to PY and Zn-P, respectively. Semi-quantitative estimates from a linear combination fitting of X-ray absorption near edge spectra (LC-XANES fitting) showed that the formation of PY decreased from 37% to 3% of the total Pb in the presence of oxalic acid and the addition of 1% P. The reduced PY formation may be associated with the increase in organic-bound Pb from 9% to 54% and decrease in carbonate associated Pb from 42% to 12% with oxalic acid addition as indicated by a chemical sequential extraction (SE) technique. Citric acid seemed to have a less adverse effect in PY formation than oxalic acid. Our data also suggests both oxalic and citric acids have less adverse effects on the efficiency of Zn-P formation. From this study we conclude that the abundance of LMWOA in soil environments can be one factor contributing to the poor efficiency of P amendments practices to effectively immobilize Pb and Zn in metal contaminated soils.

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

    OpenAIRE

    Sudadi; Sumarno; Wiki Handi

    2014-01-01

    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 R...

  20. Mesocarbon Microbead Carbon-Supported Magnesium Hydroxide Nanoparticles: Turning Spent Li-ion Battery Anode into a Highly Efficient Phosphate Adsorbent for Wastewater Treatment.

    Science.gov (United States)

    Zhang, Yan; Guo, Xingming; Wu, Feng; Yao, Ying; Yuan, Yifei; Bi, Xuanxuan; Luo, Xiangyi; Shahbazian-Yassar, Reza; Zhang, Cunzhong; Amine, Khalil

    2016-08-24

    Phosphorus in water eutrophication has become a serious problem threatening the environment. However, the development of efficient adsorbents for phosphate removal from water is lagging. In this work, we recovered the waste material, graphitized carbon, from spent lithium ion batteries and modified it with nanostructured Mg(OH)2 on the surface to treat excess phosphate. This phosphate adsorbent shows one of the highest phosphate adsorption capacities to date, 588.4 mg/g (1 order of magnitude higher than previously reported carbon-based adsorbents), and exhibits decent stability. A heterogeneous multilayer adsorption mechanism was proposed on the basis of multiple adsorption results. This highly efficient adsorbent from spent Li-ion batteries displays great potential to be utilized in industry, and the mechanism study paved a way for further design of the adsorbent for phosphate adsorption. PMID:27463402

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

    Science.gov (United States)

    Gordon, Lyle M; Joester, Derk

    2015-01-01

    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.

  2. 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.

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

    Science.gov (United States)

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.

    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.

  4. Impact of salinity on the anaerobic metabolism of phosphate-accumulating organisms (PAO) and glycogen-accumulating organisms (GAO).

    Science.gov (United States)

    Welles, L; Lopez-Vazquez, C M; Hooijmans, C M; van Loosdrecht, M C M; Brdjanovic, D

    2014-09-01

    The use of saline water as secondary quality water in urban environments for sanitation is a promising alternative towards mitigating fresh water scarcity. However, this alternative will increase the salinity in the wastewater generated that may affect the biological wastewater treatment processes, such as biological phosphorus removal. In addition to the production of saline wastewater by the direct use of saline water in urban environments, saline wastewater is also generated by some industries. Intrusion of saline water into the sewers is another source of salinity entering the wastewater treatment plant. In this study, the short-term effects of salinity on the anaerobic metabolism of phosphate-accumulating organisms (PAO) and glycogen-accumulating organisms (GAO) were investigated to assess the impact of salinity on enhanced biological phosphorus removal. Hereto, PAO and GAO cultures enriched at a relatively low salinity level (0.02 % W/V) were exposed to salinity concentrations of up to 6 % (as NaCl) in anaerobic batch tests. It was demonstrated that both PAO and GAO are affected by higher salinity levels, with PAO being the more sensitive organisms to the increasing salinity. The maximum acetate uptake rate of PAO decreased by 71 % when the salinity increased from 0 to 1 %, while that of GAO decreased by 41 % for the same salinity increase. Regarding the stoichiometry of PAO, a decrease in the P-release/HAc uptake ratio accompanied with an increase in the glycogen consumption/HAc uptake ratio was observed for PAO when the salinity increased from 0 to 2 % salinity, indicating a metabolic shift from a poly-P-dependent to a glycogen-dependent metabolism. The anaerobic maintenance requirements of PAO and GAO increased as the salinity concentrations risen up to 4 % salinity. PMID:24831025

  5. Randomized crossover study comparing the phosphate-binding efficacy of calcium ketoglutarate versus calcium carbonate in patients on chronic hemodialysis.

    Science.gov (United States)

    Bro, S; Rasmussen, R A; Handberg, J; Olgaard, K; Feldt-Rasmussen, B

    1998-02-01

    The objective of the study was to evaluate the phosphate-binding efficacy, side effects, and cost of therapy of calcium ketoglutarate granulate as compared with calcium carbonate tablets in patients on chronic hemodialysis. The study design used was a randomized, crossover open trial, and the main outcome measurements were plasma ionized calcium levels, plasma phosphate levels, plasma intact parathyroid hormone (PTH) levels, requirements for supplemental aluminum-aminoacetate therapy, patient tolerance, and cost of therapy. Nineteen patients on chronic hemodialysis were treated with a dialysate calcium concentration of 1.25 mmol/L and a fixed alfacalcidol dose for at least 2 months. All had previously tolerated therapy with calcium carbonate. Of the 19 patients included, 10 completed both treatment arms. After 12 weeks of therapy, the mean (+/-SEM) plasma ionized calcium level was significantly lower in the ketoglutarate arm compared with the calcium carbonate arm (4.8+/-0.1 mg/dL v 5.2+/-0.1 mg/dL; P = 0.004), whereas the mean plasma phosphate (4.5+/-0.3 mg/dL v 5.1+/-0.1 mg/dL) and PTH levels (266+/-125 pg/mL v 301+/-148 pg/mL) did not differ significantly between the two treatment arms. Supplemental aluminum-aminoacetate was not required during calcium ketoglutarate treatment, while two patients needed this supplement when treated with calcium carbonate. Five of 17 (29%) patients were withdrawn from calcium ketoglutarate therapy within 1 to 2 weeks due to intolerance (anorexia, vomiting, diarrhea, general uneasiness), whereas the remaining 12 patients did not experience any side effects at all. The five patients with calcium ketoglutarate intolerance all had pre-existing gastrointestinal symptoms; four of them had received treatment with cimetidine or omeprazol before inclusion into the study. Calculations based on median doses after 12 weeks showed that the cost of the therapy in Denmark was 10 times higher for calcium ketoglutarate compared with calcium

  6. Sulfurised carbohydrates: An important sedimentary sink for organic carbon?

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Kok, M.D.; Koster, J.; Schouten, S.

    1998-01-01

    In contrast to the general belief that carbohydrate carbon (CCHO) is preferentially degraded and is not extensively preserved in the sedimentary record, it is shown here that CCHO forms a large fraction of the organic matter (OM) of the total organic carbon (TOC)-rich upper Jurassic Kimmeridge Clay

  7. Explorations of soil microbial processes driven by dissolved organic carbon

    NARCIS (Netherlands)

    Straathof, A.L.

    2015-01-01

    Explorations of soil microbial processes driven by dissolved organic carbon Angela L. Straathof June 17, 2015, Wageningen UR ISBN 978-94-6257-327-7 Abstract Dissolved organic carbon (DOC) is a complex, heterogeneous mixture of C compounds which, as

  8. 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 an

  9. Organic carbon dynamics in mangrove ecosystems: a review

    OpenAIRE

    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 and benthic microalgae are usually the most important autochthonous carbon sources. Depending on local conditions, phytoplankton and seagrass detritus imported with tides may represent a significant ...

  10. Net carbon flux in organic and conventional olive production systems

    Science.gov (United States)

    Saeid Mohamad, Ramez; Verrastro, Vincenzo; Bitar, Lina Al; Roma, Rocco; Moretti, Michele; Chami, Ziad Al

    2014-05-01

    Agricultural systems are considered as one of the most relevant sources of atmospheric carbon. However, agriculture has the potentiality to mitigate carbon dioxide mainly through soil carbon sequestration. Some agricultural practices, particularly fertilization and soil management, can play a dual role in the agricultural systems regarding the carbon cycle contributing to the emissions and to the sequestration process in the soil. Good soil and input managements affect positively Soil Organic Carbon (SOC) changes and consequently the carbon cycle. The present study aimed at comparing the carbon footprint of organic and conventional olive systems and to link it to the efficiency of both systems on carbon sequestration by calculating the net carbon flux. Data were collected at farm level through a specific and detailed questionnaire based on one hectare as a functional unit and a system boundary limited to olive production. Using LCA databases particularly ecoinvent one, IPCC GWP 100a impact assessment method was used to calculate carbon emissions from agricultural practices of both systems. Soil organic carbon has been measured, at 0-30 cm depth, based on soil analyses done at the IAMB laboratory and based on reference value of SOC, the annual change of SOC has been calculated. Substracting sequestrated carbon in the soil from the emitted on resulted in net carbon flux calculation. Results showed higher environmental impact of the organic system on Global Warming Potential (1.07 t CO2 eq. yr-1) comparing to 0.76 t CO2 eq. yr-1 in the conventional system due to the higher GHG emissions caused by manure fertilizers compared to the use of synthetic foliar fertilizers in the conventional system. However, manure was the main reason behind the higher SOC content and sequestration in the organic system. As a resultant, the organic system showed higher net carbon flux (-1.7 t C ha-1 yr-1 than -0.52 t C ha-1 yr-1 in the conventional system reflecting higher efficiency as a

  11. 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.

  12. Organic carbon inventories in natural and restored Ecuadorian mangrove forests

    Directory of Open Access Journals (Sweden)

    Amanda G. DelVecchia

    2014-05-01

    Full Text Available Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g. Results suggest that average soil carbon storage is 0.055 ± 0.002 g cm−3 (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE up to 1 m deep in natural sites, and 0.058 ± 0.002 g cm−3 (8.0 ± 0.3% in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks.

  13. Organic carbon inventories in natural and restored Ecuadorian mangrove forests.

    Science.gov (United States)

    DelVecchia, Amanda G; Bruno, John F; Benninger, Larry; Alperin, Marc; Banerjee, Ovik; de Dios Morales, Juan

    2014-01-01

    Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested) surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g). Results suggest that average soil carbon storage is 0.055 ± 0.002 g cm(-3) (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE) up to 1 m deep in natural sites, and 0.058 ± 0.002 g cm(-3) (8.0 ± 0.3%) in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks. PMID:24883249

  14. 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 globally 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 magnesium per square meters 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 magnesium per square meters 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 global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while opposite is true in urban areas in India and China.

  15. An experimental study on the effects of nutrient enrichment on organic carbon persistence in the western Pacific oligotrophic gyre

    Science.gov (United States)

    Liu, J.; Jiao, N.; Tang, K.

    2014-09-01

    Carbon sequestration in the ocean is of great concern with respect to the mitigation of global warming. How to hold the fixed organic carbon in the presence of tremendous numbers of heterotrophic microorganisms in marine environments is the central issue. We previously hypothesized that excessive nutrients would ultimately decrease the storage of organic carbon in marine environments. To test this, a series of in situ nutrient enrichment incubation experiments were conducted at a site (17.59° N, 127.00° E) within the western Pacific oligotrophic gyre. Five treatments were employed: glucose (Glu), algal exudation organic material (EOM), nitrate (N) and phosphate (P), N and P in combination with glucose and a control with no added nutrients. The results showed that the dissolved organic carbon consumption rates and bacterial community specific growth rates were enhanced by inorganic nutrient enrichment treatments during the initial 48 h incubation. At the end of 14 days of incubation, about one-third (average 3.3 μmol C kg-1) more organic carbon was respired in the glucose-enriched incubation with the addition of inorganic nutrients compared to that without. In contrast, when nutrients were limiting, glucose could not be efficiently used by the bacteria and thus it remained in the environment. These results suggest that repletion of inorganic nutrients could facilitate microbial consumption of organic carbon and thus has a significant impact on carbon cycling in the environment.

  16. 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)

    Highlights: → The effect of NaNO2 on surface morphology of iron-phosphate coatings were determined. → Better corrosion stability of polyester coating on phosphated steel without NaNO2. → 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 NaNO2 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 NaNO2-free bath.

  17. Dissolved organic carbon release by marine macrophytes

    Directory of Open Access Journals (Sweden)

    C. Barrón

    2012-02-01

    Full Text Available Estimates of dissolved organic carbon (DOC release by marine macrophyte communities (seagrass meadows and macroalgal beds were obtained experimentally using in situ benthic chambers. The effect of light availability on DOC release by macrophyte communities was examined in two communities both by comparing net DOC release under light and dark, and by examining the response of net DOC release to longer-term (days experimental shading of the communities. All most 85% of the seagrass communities and almost all of macroalgal communities examined acted as net sources of DOC. There was a weak tendency for higher DOC fluxes under light than under dark conditions in seagrass meadow. There is no relationship between net DOC fluxes and gross primary production (GPP and net community production (NCP, however, this relationship is positive between net DOC fluxes and community respiration. Net DOC fluxes were not affected by shading of a T. testudinum community in Florida for 5 days, however, shading of a mixed seagrass meadow in the Philippines led to a significant reduction on the net DOC release when shading was maintained for 6 days compared to only 2 days of shading. Based on published and unpublished results we also estimate the global net DOC production by marine macrophytes. The estimated global net DOC flux, and hence export, from marine macrophyte is about 0.197 ± 0.015 Pg C yr−1 or 0.212 ± 0.016 Pg C yr−1 depending if net DOC flux by seagrass meadows was estimated by taking into account the low or high global seagrass area, respectively.

  18. Tillage Effect on Organic Carbon in a Purple Paddy Soil

    Institute of Scientific and Technical Information of China (English)

    HUANG Xue-Xia; GAO Ming; WEI Chao-Fu; XIE De-Ti; PAN Gen-Xing

    2006-01-01

    The distribution and storage of soil organic carbon (SOC) based on a long-term experiment with various tillage systems were studied in a paddy soil derived from purple soil in Chongqing, China. Organic carbon storage in the 0-20and 0-40 cm soil layers under different tillage systems were in an order: ridge tillage with rice-rape rotation (RT-rr)> conventional tillage with rice only (CT-r) > ridge tillage with rice only (RT-r) > conventional tillage with rice-rape rotation (CT-rr). The RT-rr system had significantly higher levels of soil organic carbon in the 0-40 cm topsoil, while the proportion of the total remaining organic carbon in the total soil organic carbon in the 0-10 cm layer was greatest in the RT-rr system. This was the reason why the RT-rr system enhanced soil organic carbon storage. These showed that tillage system type was crucial for carbon storage. Carbon levels in soil humus and crop-yield results showed that the RT-rr system enhanced soil fertility and crop productivity. Adoption of this tillage system would be beneficial both for environmental protection and economic development.

  19. Soil organic matter as factor of carbon cycle in nature

    International Nuclear Information System (INIS)

    Soil organic matter represents mos important pool of carbon in nature. Have been estimated content about 2000 Pg of carbon in soil cover of Earth and about 500 Pg C in plant biomass. In the global C cycle we can identify about 60 Pg C yearly removed from soil into the air and same quantities of C removed from air back to the soil. Carbon (as CO2 mainly) is directly emitted into the air from soil organic matter (after mineralization and back carbon removing from air into the soil is realized through soil and plant living biomass. (Author)

  20. 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.

  1. Growth and phosphorus uptake of sorghum plants in salt affected soil as affected by organic materials composted with rock phosphate

    International Nuclear Information System (INIS)

    A field experiment was conducted to determine the influence of different organic materials, Farm yard manure (FYM), Humic acid (HA) and Press mud (PM) and their composts prepared with rock phosphate on the growth and phosphorus (P) uptake of sorghum (Sorghum bicolor L.). The experiment was conducted in Randomized Complete Block design with three replication in salt affected soil at research farm of botanical garden Azakhel Nowshera during kharif 2012. Fertilizers were applied at the rate of 120- 90-60 kg ha/sup -1/ N, P and K, respectively. The source of N was urea and organic materials in composted and non composted form. Single super phosphate, rock phosphate, organic materials and their composts were used as P source, while sulphate of potash was used as source of K. The organic materials were applied before crop sowing at recommended level on the basis of their P content. The maximum and significantly (p=0.05) increased sorghum total dry matter yield of 23733 kg ha/sup -1/, emergence m/sup -2/ of 142 and plant height of 147 cm were observed in the treatment where composts of FYM, HA and PM were applied in combination. Increase in soil organic matter content was recorded by the application of composts of different organic materials, while decreasing trend was found in the values of soil electrical conductivity (ECe) and sodium adsorption ratio (SAR). Maximum plant N uptake of 159 kg ha/sup -1/, P uptake of 62.5 kg ha/sup -1/ and K uptake of 557 kg ha/sup -1/ were noted in the treatment where a combination of composts of FYM, HA and PM were added. Results suggest that the use of composts of different organic materials and RP are environment friendly and have the potential to improve sorghum growth, plants nutrient uptake and ameliorate salt affected soils. (author)

  2. Impact of salinity on the aerobic metabolism of phosphate-accumulating organisms.

    Science.gov (United States)

    Welles, L; Lopez-Vazquez, C M; Hooijmans, C M; van Loosdrecht, M C M; Brdjanovic, D

    2015-04-01

    The use of saline water in urban areas for non-potable purposes to cope with fresh water scarcity, intrusion of saline water, and disposal of industrial saline wastewater into the sewerage lead to elevated salinity levels in wastewaters. Consequently, saline wastewater is generated, which needs to be treated before its discharge into surface water bodies. The objective of this research was to study the effects of salinity on the aerobic metabolism of phosphate-accumulating organisms (PAO), which belong to the microbial populations responsible for enhanced biological phosphorus removal (EBPR) in activated sludge systems. In this study, the short-term impact (hours) of salinity (as NaCl) was assessed on the aerobic metabolism of a PAO culture, enriched in a sequencing batch reactor (SBR). All aerobic PAO metabolic processes were drastically affected by elevated salinity concentrations. The aerobic maintenance energy requirement increased, when the salinity concentration rose up to a threshold concentration of 2 % salinity (on a W/V basis as NaCl), while above this concentration, the maintenance energy requirements seemed to decrease. All initial rates were affected by salinity, with the NH4- and PO4-uptake rates being the most sensitive. A salinity increase from 0 to 0.18 % caused a 25, 46, and 63 % inhibition of the O2, PO4, and NH4-uptake rates. The stoichiometric ratios of the aerobic conversions confirmed that growth was the process with the highest inhibition, followed by poly-P and glycogen formation. The study indicates that shock loads of 0.18 % salt, which corresponds to the use or intrusion of about 5 % seawater may severely affect the EBPR process already in wastewater treatment plants not exposed regularly to high salinity concentrations. PMID:25524698

  3. Membrane Organization and Ionization Behavior of the Minor but Crucial Lipid Ceramide-1-Phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Kooijman, Edgar E.; Sot, Jesus; Montes, L.-Ruth; Alonso, Alicia; Gericke, Arne; de Kruijff, Ben; Kumar, Satyendra; Goni, Felix M. (Utrecht); (Kent); (Basque)

    2008-08-06

    Ceramide-1-phosphate (Cer-1-P), one of the simplest of all sphingophospholipids, occurs in minor amounts in biological membranes. Yet recent evidence suggests important roles of this lipid as a novel second messenger with crucial tasks in cell survival and inflammatory responses. We present a detailed description of the physical chemistry of this hitherto little explored membrane lipid. At full hydration Cer-1-P forms a highly organized subgel (crystalline) bilayer phase (L{sub c}) at low temperature, which transforms into a regular gel phase (L{sub {beta}}) at {approx}45 C, with the gel to fluid phase transition (L{sub {beta}}-L{sub {alpha}}) occurring at {approx}65 C. When incorporated at 5mol % in a phosphatidylcholine bilayer, the pK{sub a2} of Cer-1-P, 7.39{+-}0.03, lies within the physiological pH range. Inclusion of phosphatidylethanolamine in the phosphatidylcholine bilayer, at equimolar ratio, dramatically reduces the pK{sub a2} to 6.64{+-}0.03. We explain these results in light of the novel electrostatic/hydrogen bond switch model described recently for phosphatidic acid. In mixtures with dielaidoylphosphatidylethanolamine, small concentrations of Cer-1-P cause a large reduction of the lamellar-to-inverted hexagonal phase transition temperature, suggesting that Cer-1-P induces, like phosphatidic acid, negative membrane curvature in these types of lipid mixtures. These properties place Cer-1-P in a class more akin to certain glycerophospholipids (phosphatidylethanolamine, phosphatidic acid) than to any other sphingolipid. In particular, the similarities and differences between ceramide and Cer-1-P may be relevant in explaining some of their physiological roles.

  4. Membrane organization and ionization behavior of the minor but crucial lipid ceramide-1-phosphate.

    Science.gov (United States)

    Kooijman, Edgar E; Sot, Jesús; Montes, L-Ruth; Alonso, Alicia; Gericke, Arne; de Kruijff, Ben; Kumar, Satyendra; Goñi, Felix M

    2008-06-01

    Ceramide-1-phosphate (Cer-1-P), one of the simplest of all sphingophospholipids, occurs in minor amounts in biological membranes. Yet recent evidence suggests important roles of this lipid as a novel second messenger with crucial tasks in cell survival and inflammatory responses. We present a detailed description of the physical chemistry of this hitherto little explored membrane lipid. At full hydration Cer-1-P forms a highly organized subgel (crystalline) bilayer phase (L(c)) at low temperature, which transforms into a regular gel phase (L(beta)) at approximately 45 degrees C, with the gel to fluid phase transition (L(beta)-L(alpha)) occurring at approximately 65 degrees C. When incorporated at 5 mol % in a phosphatidylcholine bilayer, the pK(a2) of Cer-1-P, 7.39 +/- 0.03, lies within the physiological pH range. Inclusion of phosphatidylethanolamine in the phosphatidylcholine bilayer, at equimolar ratio, dramatically reduces the pK(a2) to 6.64 +/- 0.03. We explain these results in light of the novel electrostatic/hydrogen bond switch model described recently for phosphatidic acid. In mixtures with dielaidoylphosphatidylethanolamine, small concentrations of Cer-1-P cause a large reduction of the lamellar-to-inverted hexagonal phase transition temperature, suggesting that Cer-1-P induces, like phosphatidic acid, negative membrane curvature in these types of lipid mixtures. These properties place Cer-1-P in a class more akin to certain glycerophospholipids (phosphatidylethanolamine, phosphatidic acid) than to any other sphingolipid. In particular, the similarities and differences between ceramide and Cer-1-P may be relevant in explaining some of their physiological roles. PMID:18296489

  5. Volatile organic compound emissions in relation to plant carbon fixation and the terrestrial carbon budget

    NARCIS (Netherlands)

    Kesselmeier, J.; Ciccioli, P.; Kuhn, U.; Stefani, P.; Biesenthal, T.; Rottenberger, S.; Wolf, A.; Vitullo, M.; Valentini, R.; Nobre, A.; Kabat, P.; Andreae, M.O.

    2002-01-01

    A substantial amount of carbon is emitted by terrestrial vegetation as biogenic volatile organic compounds (VOC), which contributes to the oxidative capacity of the atmosphere, to particle production and to the carbon cycle. With regard to the carbon budget of the terrestrial biosphere, a release of

  6. Limits to soil carbon stability; Deep, ancient soil carbon decomposition stimulated by new labile organic inputs

    Science.gov (United States)

    Soil carbon (C) pools store about one-third of the total terrestrial organic carbon. Deep soil C pools (below 1 m) are thought to be stable due to their low biodegradability, but little is known about soil microbial processes and carbon dynamics below the soil surface, or how global change might aff...

  7. Carbon dioxide capture and use: organic synthesis using carbon dioxide from exhaust gas.

    Science.gov (United States)

    Kim, Seung Hyo; Kim, Kwang Hee; Hong, Soon Hyeok

    2014-01-13

    A carbon capture and use (CCU) strategy was applied to organic synthesis. Carbon dioxide (CO2) captured directly from exhaust gas was used for organic transformations as efficiently as hyper-pure CO2 gas from a commercial source, even for highly air- and moisture-sensitive reactions. The CO2 capturing aqueous ethanolamine solution could be recycled continuously without any diminished reaction efficiency.

  8. Evaluation of organic carbon analyzers for space application. [for water reclamation

    Science.gov (United States)

    1984-01-01

    The state-of-the-art technology for organic carbon analysis in space applications is evaluated. An investigation into total organic carbon (TOC) analysis has identified a variety of schemes which include different methods for: (1) separation of inorganic carbon from organic carbon and/or differentiation of inorganic carbon from organic carbon; (2) reaction of organic carbon to form a quantifiable species; and (3) detection and measurement of that species. Each method option is discussed.

  9. Floodplain Organic Carbon Storage in the Central Yukon River Basin

    Science.gov (United States)

    Lininger, K.; Wohl, E.

    2014-12-01

    Floodplain storage of organic carbon is an important aspect of the global carbon cycle that is not well understood or quantified. Although it is understood that rivers transport organic carbon to the ocean, little is known about the quantity of stored carbon in boreal floodplains and the influence of fluvial processes on this storage. We present results on total organic carbon (TOC) content within the floodplains of two rivers, the Dall River and Preacher Creek, in the central Yukon River Basin in the Yukon Flats National Wildlife Refuge of Alaska. The results indicate that organic carbon storage is influenced by fluvial disturbance and grain size. The Dall River, which contains a large amount of floodplain carbon, is meandering and incised, with well-developed floodplain soils, a greater percentage of relatively old floodplain surfaces and a slower floodplain turnover time, and finer grain sizes. Preacher Creek stores less TOC, transports coarser grain sizes, and has higher rates of avulsion and floodplain turnover time. Within the floodplain of a particular river, large spatial heterogeneity in TOC content also exists as a function of depositional environment and age and vegetation community of the site. In addition, saturated regions of the floodplains, such as abandoned channels and oxbow lakes, contain more TOC compared to drier floodplain environments. Frozen alluvial soils likely contain carbon that could be released into the environment with melting permafrost, and thus quantifying the organic carbon content in the active layer of floodplain soils could provide insight into the characteristics of the permafrost beneath. The hydrology in these regions is changing due to permafrost melt, and floodplain areas usually saturated could be dried out, causing breakdown and outgassing of carbon stored in previously saturated soils. Ongoing work will result in a first-order estimate of active-layer floodplain carbon storage for the central Yukon River Basin.

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

    OpenAIRE

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

    2014-01-01

    Oceanic dissolved organic carbon (DOC) contains as much carbon as Earth’s atmosphere, yet its cycling timescales and composition remain poorly constrained. We use serial oxidation experiments to measure the quantitative distribution of carbon isotopes inside the DOC reservoir, allowing us to estimate both its cycling timescales and source distribution. We find that a large portion of deep water DOC has a modern radiocarbon age and a fast turnover time supported by particle dissolution. In add...

  11. Organic carbon inventories in natural and restored Ecuadorian mangrove forests

    OpenAIRE

    DelVecchia, Amanda G.; John F Bruno; Larry Benninger; Marc Alperin; Ovik Banerjee; Juan de Dios Morales

    2014-01-01

    Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hamp...

  12. Simple, Micro-Miniature Total Organic Carbon Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of a simple method for on-orbit or advanced mission Total Organic Carbon (TOC) monitoring has been a goal for many years. This proposal seeks to develop...

  13. Anomalous 13C enrichment in modern marine organic carbon

    Science.gov (United States)

    Arthur, M.A.; Dean, W.E.; Claypool, G.E.

    1985-01-01

    Marine organic carbon is heavier isotopically (13C enriched) than most land-plant or terrestrial organic C1. Accordingly, ??13C values of organic C in modern marine sediments are routinely interpreted in terms of the relative proportions of marine and terrestrial sources of the preserved organic matter2,3. When independent geochemical techniques are used to evaluate the source of organic matter in Cretaceous or older rocks, those rocks containing mostly marine organic C are found typically to have lighter (more-negative) ??13C values than rocks containing mostly terrestrial organic C. Here we conclude that marine photosynthesis in mid-Cretaceous and earlier oceans generally resulted in a greater fractionation of C isotopes and produced organic C having lighter ??13C values. Modern marine photosynthesis may be occurring under unusual geological conditions (higher oceanic primary production rates, lower PCO2) that limit dissolved CO2 availability and minimize carbon isotope fractionation4. ?? 1985 Nature Publishing Group.

  14. Real World of Industrial Chemistry: Organic Chemicals from Carbon Monoxide.

    Science.gov (United States)

    Kolb, Kenneth E.; Kolb, Doris

    1983-01-01

    Carbon Monoxide obtained from coal may serve as the source for a wide variety of organic compounds. Several of these compounds are discussed, including phosgene, benzaldehyde, methanol, formic acid and its derivatives, oxo aldehydes, acrylic acids, and others. Commercial reactions of carbon monoxide are highlighted in a table. (JN)

  15. Estimation of soil organic carbon reservoir in China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The paper respectively adopted physio-chemical properties of every soil stratum from 2473 soil profiles of the second national soil survey. The corresponding carbon content of soils is estimated by utilizing conversion coefficient 0.58. In the second soil survey, the total amount of soil organic carbon is about 924.18×108t and carbon density is about 10.53 kgC/m2 in China according to the area of 877.63×106 hm2 surveyed throughout the country. The spatial distribution characteristics of soil organic carbon in China is that the carbon storage increases when latitude increases in eastern China and the carbon storage decreases when longitude reduces in northern China. A transitional zone with great variation in carbon storage exists. Moreover, there is an increasing tendency of carbon density with decrease of latitude in western China. Soil circle is of great significance to global change, but with substantial difference in soil spatial distribution throughout the country. Because the structure of soil is inhomogeneous, it could bring some mistakes in estimating soil carbon reservoirs. It is necessary to farther resolve soil respiration and organic matter conversion and other questions by developing uniform and normal methods of measurement and sampling.

  16. 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...

  17. SIMULATION EXPERIMENT OF ORGANIC FARMING SYSTEM: CHANGES OF SOIL ORGANIC CARBON AND MICROBIAL COMMUNITIES BY ORGANIC FERTILIZATION

    OpenAIRE

    Wang, Run-Chi; Zong, Liang-Gang; Yan, Jia; Luo, Min; Yun-feng HU

    2014-01-01

    Soil beneficial microbe products are allowed to apply in organic farming system as soil amendment. Effects of different organic fertilization on soil organic carbon (SOC) and microbes were analyzed in this study in order to improve fertilization technology. Simulation culture experiment was designed and operated in the laboratory to exclude uncertainties, such as environment and human operations of the organic farm. Results showed that more soil microbial biomass carbon (MBC) was discovered i...

  18. Carbon isotopic studies of organic matter in Precambrian rocks.

    Science.gov (United States)

    Oehler, D. Z.; Schopf, J. W.; Kvenvolden, K. A.

    1972-01-01

    A survey has been undertaken of the carbon composition of the total organic fraction of a suite of Precambrian sediments to detect isotopic trends possibly correlative with early evolutionary events. Early Precambrian cherts of the Fig Tree and upper and middle Onverwacht groups of South Africa were examined for this purpose. Reduced carbon in these cherts was found to be isotopically similar to photosynthetically produced organic matter of younger geological age. Reduced carbon in lower Onverwacht cherts was found to be anomalously heavy; it is suggested that this discontinuity may reflect a major event in biological evolution.

  19. 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

    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...... important and of a similar magnitude. Overall, most of the measured O2 flux into the sediment was used to oxidized reduced inorganic species and not organic carbon. We suspect that the importance of O2 respiration in many coastal sediments has been overestimated, whereas metal oxide reduction (both Fe...

  20. Carbon Mineralizability Determines Interactive Effects on Mineralization of Pyrogenic Organic Matter and Soil Organic Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Whitman, Thea L.; Zhu, Zihua; Lehmann, Johannes C.

    2014-10-31

    Soil organic carbon (SOC) is a critical and active pool in the global C cycle, and the addition of pyrogenic organic matter (PyOM) has been shown to change SOC cycling, increasing or decreasing mineralization rates (often referred to as priming). We adjusted the amount of easily mineralizable C in the soil, through 1-day and 6-month pre-incubations, and in PyOM made from maple wood at 350°C, through extraction. We investigated the impact of these adjustments on C mineralization interactions, excluding pH and nutrient effects and minimizing physical effects. We found short-term increases (+20-30%) in SOC mineralization with PyOM additions in the soil pre-incubated for 6 months. Over the longer term, both the 6-month and 1-day pre-incubated soils experienced net ~10% decreases in SOC mineralization with PyOM additions. This was possibly due to stabilization of SOC on PyOM surfaces, suggested by nanoscale secondary ion mass spectrometry. Additionally, the duration of pre-incubation affected priming interactions, indicating that there may be no optimal pre-incubation time for SOC mineralization studies. We show conclusively that relative mineralizability of SOC in relation to PyOM-24 C is an important determinant of the effect of PyOM additions on SOC mineralization.

  1. 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...

  2. Assessment of the Impact of Climate Change and Land Management Change on Soil Organic Carbon Content, Leached Carbon Rates and Dissolved Organic Carbon Concentrations

    NARCIS (Netherlands)

    Stergiadi, Maria; de Nijs, Ton; van der Perk, Marcel; Bonten, Luc

    2014-01-01

    Climate change is projected to significantly affect the concentrations and mobility of contaminants, such as metals and pathogens, in soil, groundwater and surface water. Climate- and land management-induced changes in soil organic carbon and dissolved organic carbon levels may promote the transport

  3. Subduction of Organic Carbon into the Earth

    Science.gov (United States)

    Plank, T. A.; Malinverno, A.

    2015-12-01

    Seafloor sediments approach active subduction zones with small amounts (generally Indus and Begal Fans, Gulf of Alaska, Cascadia, etc). Together, terrigenous turbidites make up about 60% of the global subducted sediment (GLOSS), and thus have a strong control on the concentration of OC in GLOSS. Sites dominated by terrigenous turbidites have 0.4 wt% OC on average (1sd = 0.1 wt%), and GLOSS is very similar, yielding about 6 MtC/yr OC subducted globally. This flux is enough to subduct the entire surface pool of OC every 2.6 Ga, which if not returned, or returned in a more oxidized form, could contribute to a significant rise in oxygen at the surface of the Earth. Seemingly fortuitously, the OC/total carbon fraction in GLOSS is 20%, very near the long term average required to maintain the isotopic composition of marine carbonates at ~ 0 per mil d13C over much of Earth history.

  4. The Feasibility of Modified Magnesia-Phosphate Cement as a Heat Resistant Adhesive for Strengthening Concrete with Carbon Sheets

    Directory of Open Access Journals (Sweden)

    Ailian Zhang

    2016-06-01

    Full Text Available External bonding of carbon fiber sheets has become a popular technique for strengthening concrete structures all over the world. Epoxy adhesive, which is used to bond the carbon fiber sheets and concrete, deteriorates rapidly when being exposed to high temperatures. This paper presents a high-temperature-resistant modified magnesia-phosphate cement (MPC with the compressive strength that does not decrease at the temperature of 600 °C. The bond properties of both the modified MPC and the epoxy adhesive between externally bonded carbon fiber sheets and concrete were evaluated by using a double-shear test method after exposure to elevating temperatures from 105 °C to 500 °C. The results showed that the bond strength of the modified MPC at room temperature (RT is much higher than that of the epoxy resin. Full carbonation with almost 0 MPa was detected for the epoxy sample after the exposure to 300 °C, while only 40% reduction of bond strength was tested for the modified MPC sample. Although the modified MPC specimens failed through interlaminar slip of fiber strips instead of complete debonding, the MPC specimens performed higher bond strength than epoxy resin at ambient temperature, and retained much higher bond strength at elevated temperatures. It could be concluded that it is feasible to strengthen concrete structural members with externally bonded carbon fiber sheets using the modified MPC instead of epoxy adhesive. Furthermore, the use of the modified MPC as the binder between carbon fiber sheets and concrete can be less expensive and an ecologically friendly alternative.

  5. Biostimulation of Oil Sands Process-Affected Water with Phosphate Yields Removal of Sulfur-Containing Organics and Detoxification.

    Science.gov (United States)

    Quesnel, Dean M; Oldenburg, Thomas B P; Larter, Stephen R; Gieg, Lisa M; Chua, Gordon

    2015-11-01

    The ability to mitigate toxicity of oil sands process-affected water (OSPW) for return into the environment is an important issue for effective tailings management in Alberta, Canada. OSPW toxicity has been linked to classical naphthenic acids (NAs), but the toxic contribution of other acid-extractable organics (AEOs) remains unknown. Here, we examine the potential for in situ bioremediation of OSPW AEOs by indigenous algae. Phosphate biostimulation was performed in OSPW to promote the growth of indigenous photosynthetic microorganisms and subsequent toxicity and chemical changes were determined. After 12 weeks, the AEO fraction of phosphate-biostimulated OSPW was significantly less toxic to the fission yeast Schizosaccharomyces pombe than unstimulated OSPW. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) analysis of the AEO fraction in phosphate-biostimulated OSPW showed decreased levels of SO3 class compounds, including a subset that may represent linear arylsulfonates. A screen with S. pombe transcription factor mutant strains for growth sensitivity to the AEO fraction or sodium dodecylbenzenesulfonate revealed a mode of toxic action consistent with oxidative stress and detrimental effects on cellular membranes. These findings demonstrate a potential algal-based in situ bioremediation strategy for OSPW AEOs and uncover a link between toxicity and AEOs other than classical NAs.

  6. Review and suggestions for estimating particulate organic carbon and dissolved organic carbon inventories in the ocean using remote sensing data

    Institute of Scientific and Technical Information of China (English)

    PAN Delu; LIU Qiong; BAI Yan

    2014-01-01

    Dissolved organic carbon (DOC) and particulate organic carbon (POC) are basic variables for the ocean carbon cycle. Knowledge of the distribution and inventory of these variables is important for a better es-timation and understanding of the global carbon cycle. Owing to its considerable advantages in spatial and temporal coverage, remote sensing data provide estimates of DOC and POC inventories, which are able to give a synthetic view for the distribution and transportation of carbon pools. To estimate organic car-bon inventories using remote sensing involves integration of the surface concentration and vertical profile models, and the development of these models is critical to the accuracy of estimates. Hence, the distribu-tion and control factors of DOC and POC in the ocean first are briefly summarized, and then studies of DOC and POC inventories and flux estimations are reviewed, most of which are based on field data and few of which consider the vertical distributions of POC or DOC. There is some research on the estimation of POC inventory by remote sensing, mainly in the open ocean, in which three kinds of vertical profile models have been proposed:the uniform, exponential decay, and Gauss models. However, research on remote-sensing estimation of the DOC inventory remains lacking. A synthetic review of approaches used to estimate the or-ganic carbon inventories is offered and the future development of methods is discussed for such estimates using remote sensing data in coastal waters.

  7. 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)

  8. Influence of moderate pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing activated carbon.

    Science.gov (United States)

    Wang, Zhengfang; Shi, Mo; Li, Jihua; Zheng, Zheng

    2014-03-01

    A novel adsorbent based on iron oxide dispersed over activated carbon (AC) were prepared, and used for phosphate removal from aqueous solutions. The influence of pre-oxidation treatment on the physical, chemical and phosphate adsorption properties of iron-containing AC were determined. Two series of ACs, non-oxidized and oxidized carbon modified by iron (denoted as AC-Fe and AC/O-Fe), resulted in a maximum impregnated iron of 4.03% and 7.56%, respectively. AC/O-Fe showed 34.0%-46.6% higher phosphate removal efficiency than the AC-Fe did. This was first attributed to the moderate pre-oxidation of raw AC by nitric acid, achieved by dosing Fe(II) after a pre-oxidation, to obtain higher iron loading, which is favorable for phosphate adsorption. Additionally, the in-situ formed active site on the surface of carbon, which was derived from the oxidation of Fe(II) by nitric acid dominated the remarkably high efficiency with respect to the removal of phosphate. The activation energy for adsorption was calculated to be 10.53 and 18.88 kJ/mol for AC-Fe and AC/O-Fe, respectively. The results showed that the surface mass transfer and intra-particle diffusion were simultaneously occurring during the process and contribute to the adsorption mechanism.

  9. Arsenic(V) adsorption-desorption in agricultural and mine soils: Effects of organic matter addition and phosphate competition.

    Science.gov (United States)

    Arco-Lázaro, Elena; Agudo, Inés; Clemente, Rafael; Bernal, M Pilar

    2016-09-01

    High total and bioavailable concentrations of As in soils represent a potential risk for groundwater contamination and entry in the food chain. The use of organic amendments in the remediation of As-contaminated soils has been found to produce distinct effects on the solubility of As in the soil. Therefore, knowledge about As adsorption-desorption processes that govern its solubility in soil is of relevance in order to predict the behaviour of this element during these processes. In this paper, the objective was to determine As adsorption and desorption in four different soils, with and without compost addition, and also in competition with phosphate, through the determination of sorption isotherms. Batch experiments were carried out using three soils affected differently by previous mining activity of the Sierra Minera of La Unión-Cartagena (SE Spain) and an agricultural soil from Segovia province (central Spain). Adsorption was higher in the mining soils (and highest in the acidic one) than in the agricultural soils, although the latter were not affected negatively by organic matter or phosphate competition for sorption sites. The results show that As adsorption in most soils, both with and without compost, fitted better a multimolecular layer model (Freundlich), whereas As adsorption in competition with P fitted a monolayer model (Langmuir). Moreover, the use of compost and phosphate reduced the adsorption of As in the mining soils, while in the agricultural soils compost increased their low adsorption capacity. Therefore, the use of compost can be a good option to favour As immobilisation in soils of low adsorption, but knowledge of the soil composition will be crucial to predict the effects of organic amendments on As solubility in soils and its associated environmental risk.

  10. 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

  11. Beneficiation of Iraqi Akash at Phosphate Ore Using Organic Acids for the Production of Wet Process Phosphoric Acid

    Directory of Open Access Journals (Sweden)

    Mohammed Y. Eisa

    2013-12-01

    Full Text Available In the present work, leaching process studiedusing organic acids (acetic acid and lactic acid to extract phosphate from the Iraqi Akashat phosphate ore by separation of calcareous materials (mainly calcite. This approach characterized by energy conservation, environmental enhancement by recovery of calcite as calcium sulfate (gypsum, keeping the physical and chemical properties of apatite. Samples were analyzed using X-ray diffraction and FTIR spectrophotometer. From the obtained experimental data it was found that using the two organic acids yields closed purity values of the produced apatite at the optimum conditions, while at different acid concentrations, it was found that the efficiency of acetic acid is higher at the low acid concentration (2 wt%, and that lactic acid gives the higher efficiency at high acid concentration (10 wt%.Concerning the ratio of acid volume to ore weight ratio, it was found that reducing this ratio to 5 ml/gm cause an increase in the purity of apatite at the optimum concentrations of the two acids. In addition, it was found that the reaction ofthe two organic acids with the calcareous material are fast and that the optimum reaction time, in which high purity apatite produced is 10 minutes.

  12. Toward uniform and ultrathin carbon layer coating on lithium iron phosphate using liquid carbon dioxide for enhanced electrochemical performance

    Science.gov (United States)

    Hong, Seung-Ah; Kim, Dong Hyun; Chung, Kyung Yoon; Chang, Wonyoung; Yoo, Jibeom; Kim, Jaehoon

    2014-09-01

    In this communication, uniform and ultrathin carbon coating on LiFePO4 (LFP) particles are performed using liquid carbon dioxide (l-CO2)-based free-meniscus coating. The uniform and conformal coverage of the carbon layer on LFP with a thickness of 3.3 nm, and a uniform distribution of carbon on the entire surface of the LFP particle are confirmed. The carbon-coated LFP (C-LFP) with a carbon content of 1.9 wt.% obtained using l-CO2-based coating exhibits a discharge capacity of 169 mAh g-1 at 0.1 C and 71 mAh g-1 at 30 C, while much lower discharge capacity of 146 mAh g-1 at 0.1 C and 17 mAh g-1 at 30 C is observed when C-LFP with an optimized carbon content of 6.0 wt.% is prepared using conventional aqueous-based coating.

  13. Anomalous carbon-isotope ratios in nonvolatile organic material.

    Science.gov (United States)

    Kaplan, I R; Nissenbaum, A

    1966-08-12

    Organic mats are associated with sulfur deposits in Upper Pleistocene sand ridges of the coastal plain of southern Israel; black, brittle, and non-volatile, they show parallel layering but no other apparent cellular structure. Two independent carbon-14 determinations yielded ages of 27,750+/-500 and 31,370+/-1400 years. Four carbon-13:carbon-12 determinations fell within the range deltaC(13) =-82.5 to -89.3 per mille relative to the PDB standard; these appear to be the lowest values yet reported for naturally occurring high-molecular-weight organic material. The origin of the carbon is probably complex; it must have passed through at least one biologic cycle before final deposition.

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

    International Nuclear Information System (INIS)

    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 CO2 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. The Oxidant Budget of Dissolved Organic Carbon Driven Isotope Excursions

    Science.gov (United States)

    Bristow, T. F.; Kennedy, M. J.

    2008-12-01

    Negative carbon isotope values, falling below the mantle average of about -5 per mil, in carbonate phases of Ediacaran age sedimentary rocks are widely regarded as reflecting negative excursions in the carbon isotopic composition of seawater lasting millions of years. These isotopic signals form the basis of chemostratigraphic correlations between Ediacaran aged sections in different parts of the world, and have been used to track the oxidation of the biosphere. However, these isotopic values are difficult to accommodate within limits prescribed by the current understanding of the carbon cycle, and a hypothetical Precambrian ocean dissolved organic carbon (DOC) pool 100 to 1000 times the size of the modern provides a potential source of depleted carbon not considered in Phanerozoic carbon cycle budgets. We present box model results that show the remineralization of such a DOC pool to drive an isotope excursion of the magnitude observed in the geological record exhausts global budgets of free oxygen and sulfate in 800 k.y. These results are incompatible with the estimated duration of late Ediacaran isotope excursions of more than 10 m.y., as well as geochemical and biological indicators that oceanic sulfate and oxygen levels were maintained or even increased at the same time. Therefore the carbon isotope record is probably not a useful tool for monitoring oxygen levels in the atmosphere and ocean. Covariation between the carbon and oxygen isotope records is often observed during negative excursions and is indicative of local processes or diagenetic overprinting.

  16. Methodology guideline. Organization of conference neutral in carbon

    International Nuclear Information System (INIS)

    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.)

  17. Aminolysis Reaction of Glycerol Carbonate in Organic and Hydroorganic Medium

    OpenAIRE

    Nohra, Bassam; Candy, Laure; Blanco, Jean-François; Raoul, Yann; Mouloungui, Zephirin

    2012-01-01

    Aminolysis reaction of glycerol carbonate with primary amine in organic and hydroorganic media leads to the formation of two hydroxyurethane isomers and a partial decomposition of glycerol carbonate into glycerol. Aminolysis with a secondary amine promotes the condensation reaction and limits the formation of glycerol. The ratio of α versus β was determined by zgig 13C NMR. This technique permits computing the yield of α and β products in the medium. The quantity of glycerol was determined by...

  18. Carbon dioxide capture by means of cyclic organic nitrogen compounds

    OpenAIRE

    García Abuín, Alicia

    2012-01-01

    The research work included in present PhD Thesis involves the research studies to capture carbon dioxide using different cyclic nitrogen organic compounds (glucosamine (GA), chitosan (C), alkyl-pyrrolidones, pyrrolidine (PYR) and piperidine (PIP). This investigation is based on the study of three experimental systems. Each of them has characteristics potentially suitable to achieve the aim of this work, that is to say, to improve the carbon dioxide capture process, which is pre...

  19. Organic carbon in Antarctic snow: spatial trends and possible sources

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, R.; Mahalinganathan, K.; Thamban, M.; Nair, S.

    ) screw-capped glass bottles under a laminar-flow benchhousedinaC015C176Ccoldroomprocessingfacility.Carewas taken to ensure that the bottles were filled leaving no head space and were tightly sealed in order to minimize contamination from the atmosphere... addressing issues concerning global carbon dynamics. 6,7 Additionally, it has been shown that organic carbon in snow undergoes photochemical reactions, releasing reactive gas-phase species to the overlying atmosphere. 8C010 DespiteitsimportanceinairC0...

  20. Superior Electrocatalytic Activity of a Robust Carbon-Felt Electrode with Oxygen-Rich Phosphate Groups for All-Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Kim, Ki Jae; Lee, Heon Seong; Kim, Jeonghun; Park, Min-Sik; Kim, Jung Ho; Kim, Young-Jun; Skyllas-Kazacos, Maria

    2016-06-01

    A newly prepared type of carbon felt with oxygen-rich phosphate groups is proposed as a promising electrode with good stability for all-vanadium redox flow batteries (VRFBs). Through direct surface modification with ammonium hexafluorophosphate (NH4 PF6 ), phosphorus can be successfully incorporated onto the surface of the carbon felt by forming phosphate functional groups with -OH chemical moieties that exhibit good hydrophilicity. The electrochemical reactivity of the carbon felt toward the redox reactions of VO(2+) /VO2 (+) (in the catholyte) and V(3+) /V(2+) (in the anolyte) can be effectively improved owing to the superior catalytic effects of the oxygen-rich phosphate groups. Furthermore, undesirable hydrogen evolution can be suppressed by minimizing the overpotential for the V(3+) /V(2+) redox reaction in the anolyte of the VRFB. Cell-cycling tests with the catalyzed electrodes show improved energy efficiencies of 88.2 and 87.2 % in the 1(st) and 20(th)  cycles compared with 83.0 and 81.1 %, respectively, for the pristine electrodes at a constant current density of 32 mA cm(-2) . These improvements are mainly attributed to the faster charge transfer allowed by the integration of the oxygen-rich phosphate groups on the carbon-felt electrode. PMID:27106165

  1. Charcoal bed operation for optimal organic carbon removal

    International Nuclear Information System (INIS)

    Historically, evaporation, reverse osmosis or charcoal-demineralizer systems have been used to remove impurities in liquid radwaste processing systems. At Nine Mile point, we recently replaced our evaporators with charcoal-demineralizer systems to purify floor drain water. A comparison of the evaporator to the charcoal-demineralizer system has shown that the charcoal-demineralizer system is more effective in organic carbon removal. We also show the performance data of the Granulated Activated Charcoal (GAC) vessel as a mechanical filter. Actual data showing that frequent backflushing and controlled flow rates through the GAC vessel dramatically increases Total Organic Carbon (TOC) removal efficiency. GAC vessel dramatically increases Total Organic Carbon (TOC) removal efficiency. Recommendations are provided for operating the GAC vessel to ensure optimal performance

  2. Raman spectroscopy: Caution when interpreting organic carbon from oxidising environments

    Science.gov (United States)

    Brolly, Connor; Parnell, John; Bowden, Stephen

    2016-02-01

    Oxidation on Mars is primarily caused by the high influx of cosmic and solar radiation which interacts with the Martian surface. The evidence of this can be seen in the ubiquitous red colouration of the Martian sediment. This radiation will destroy most signals of life in the top few metres of the Martian surface. If organic carbon (one of the building blocks of life) is present within the accessible Martian sediments, it is very likely that it will have experienced some oxidation. ESA's ExoMars mission set to fly in 2018, has on board a miniaturised Raman spectrometer. As Raman spectroscopy is sensitive to carbonaceous material and will be primarily used to characterise organics, it is essential that the effect oxidation has on the Raman carbon signal is assessed. Oxidised carbonaceous shales were analysed using Raman spectroscopy to assess this issue. Results show that haematite has a band which occurs in the same frequency as the carbon D band, which cannot be distinguished from each other. This can lead to a misidentification of the carbon D band and a misinterpretation of the carbon order. Consequently, caution must be taken when applying Raman spectroscopy for organic carbon analysis in oxidised terrestrial and extraterrestrial environments, including on Mars.

  3. 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

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

    Science.gov (United States)

    Canfield, D. E.; Jorgensen, B. B.; Fossing, H.; Glud, R.; Gundersen, J.; Ramsing, N. B.; Thamdrup, B.; Hansen, J. W.; Nielsen, L. P.; Hall, P. O.

    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 important and of a similar magnitude. Overall, most of the measured O2 flux into the sediment was used to oxidized reduced inorganic species and not organic carbon. We suspect that the importance of O2 respiration in many coastal sediments has been overestimated, whereas metal oxide reduction (both Fe and Mn reduction) has probably been well underestimated.

  5. Toward a better understanding of coagulation for dissolved organic nitrogen using polymeric zinc-iron-phosphate coagulant.

    Science.gov (United States)

    Zhu, Guocheng; Wang, Qian; Yin, Jun; Li, Zhongwu; Zhang, Peng; Ren, Bozhi; Fan, Gongduan; Wan, Peng

    2016-09-01

    The increase of agricultural related activities and the lack of effective waste control has led to an increase of organic nitrogen in water. The development of coagulants to effectively remove dissolved organic nitrogen (DON) is a high priority in the water treatment industry. We developed a polymeric zinc-iron-phosphate (ZnFeP) coagulant and investigated its coagulation effect on DON removal. Optimum coagulant for coagulation for DON and TDN removals was characterized by the dense convex-concave packing structure differing from other zinc-based coagulant, polycrystalline structure and high content colloidal species, which could account up to 87% of the total colloidal species. Coagulation experiments showed the DON removal rate to vary greatly depending on principal components and their interaction with metals, phosphate and hydroxyl. DON removal efficiency increased with the increase of colloidal species. The coagulation was also dependent on coagulant dosage and water quality parameters: Coagulation efficiency increased with coagulant dosage in the investigated range of 1-16 mg/l, and a pH of 6 was found to be superior for the coagulation. DON removal efficiency was also higher than and linearly correlated with total dissolved nitrogen (TDN) removal, which implies that an effective coagulation for TDN is also effective for DON. The findings in this study indicate that coagulation of DON is largely influenced by coagulant composition and species. We also found the removal of DON by our newly developed polymeric ZnFeP coagulant to be effective. PMID:27192355

  6. Evaluation of Powdered Activated Carbon Efficiency in Removal of Dissolved Organic Carbon inWater Treatment

    OpenAIRE

    G.R Bonyadi nejad; R Hadian; M Saadani; B Jaberian; M.M Amin; A Khodabakhshi

    2010-01-01

    "n "nBackgrounds and Objectives: Powdered Activated$ carbon is known as a suitable absorbent for organic materials. The aim of this research is evaluation of Powdered Activated-Carbon (PAC) efficiency in removal of Dissolved Organic Carbon (DOC) in water treatment in Isfahan."nMaterials and Methods : The increase of PAC for DOC reduction has done in three paths in the Isfahan water treatment plant (WTP). These paths including: 1) Intake up to entrance of WTP 2) Intake to exit ofWTP 3) Between...

  7. Carbon with hierarchical pores from carbonized metal-organic frameworks for lithium sulphur batteries.

    Science.gov (United States)

    Xi, Kai; Cao, Shuai; Peng, Xiaoyu; Ducati, Caterina; Kumar, R Vasant; Cheetham, Anthony K

    2013-03-18

    This paper presents a novel method and rationale for utilizing carbonized MOFs for sulphur loading to fabricate cathode structures for lithium-sulphur batteries. Unique carbon materials with differing hierarchical pore structures were synthesized from four types of zinc-containing metal-organic frameworks (MOFs). It is found that cathode materials made from MOFs-derived carbons with higher mesopore (2-50 nm) volumes exhibit increased initial discharge capacities, whereas carbons with higher micropore (<2 nm) volumes lead to cathode materials with better cycle stability.

  8. Light absorption by organic carbon from wood combustion

    Directory of Open Access Journals (Sweden)

    Y. Chen

    2009-09-01

    Full Text Available Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While BC is highly absorbing, some organic compounds also have significant absorption, which is greater at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to direct aerosol radiative forcing.

    In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble organic carbon contributed to light absorption at both ultraviolet and visible wavelengths. However, a larger portion came from organic carbon that is extractable only by methanol. The spectra of water-soluble organic carbon are similar to others in the literature. We compared spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating organic aerosol with higher absorption, causing about a factor of four increase in mass-normalized absorption at visible wavelengths. A simple model suggests that, despite the absorption, both high-temperature and low-temperature carbon have negative climate forcing over a surface with average albedo.

  9. Soil Organic Carbon Erosion Assessment by Cesium-137

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Yueli; Lal, Rattan; Owens, Lloyd; Izaurralde, Roberto C.

    2001-12-31

    Soil organic carbon (SOC) is a major pool that impacts the global carbon cycle (Lal,1999). Increasing SOC pool is desirable because of its favorable effects on improving soil fertility, decreasing water and air pollution, and mitigating the greenhouse effect caused by various energy utilization activities such as fossil fuel combustion. The amount of SOC depends on kinetic competition between various input and output processes. The input processes include plant growth (plant residue, root excretion, and organic matter through-fall), addition of organic material (manure, sewage sludge, and other organic wastes) through soil management, and deposition through soil erosion. The output processes comprise decomposition into gases, leaching into groundwater, and removal through soil erosion. Assessment of these processes is one of the steps toward adopting the strategy of increasing SOC content.

  10. Carbon-coated lithium titanium phosphate nanoporous microplates with superior electrochemical performance

    Science.gov (United States)

    Huang, Zhifeng; Liu, Li; Zhou, Qian; Tan, Jinli; Yan, Zichao; Xia, Dongdong; Shu, Hongbo; Yang, Xiukang; Wang, Xianyou

    2015-10-01

    In this study, we report a facile method to synthesize carbon-coated LiTi2(PO4)3 nanoporous microplates (LTP/C MPs) using ethylenediamine as the chelating agent and carbon source. The as-prepared LTP/C MPs with thickness of 0.4 μm consist of interconnected nanosized particles embedded in nano-thickness carbon layer and well-dispersed nanopores. The carbon layer significantly improves the electrochemical performance of LiTi2(PO4)3 microplates. LTP/C MPs deliver a reversible capacity of 121 mAh g-1 at 0.2C (1C = 138 mAh g-1) and show a remarkable capacity retention of 94.2% over 100 cycles when matched with Li metal counter electrode. It also presents excellent electrochemical properties as anode material for aqueous rechargeable lithium batteries (ARLBs). LTP/C MPs//LiMn2O4 ARLB shows a high discharge capacity of 76 mAh g-1 at 20 mA g-1 and superior rate capability. The results suggest a practical stratagem to develop a novel composite in which the carbon is coated with LiTi2(PO4)3 nanoporous microplates, which can become one of the promising electrode materials for both non-aqueous and aqueous lithium ion batteries.

  11. Spatial distribution of soil organic carbon stocks in France

    Directory of Open Access Journals (Sweden)

    M. P. Martin

    2010-11-01

    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, whereby it can influence the course of climate change. Changes in soil organic soil stocks (SOCS are now taken into account in international negotiations regarding climate change. Consequently, developing sampling schemes and models for estimating the spatial distribution of SOCS 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 circa 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 SOCS 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 SOCS for the whole of metropolitan 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 soil organic carbon for such soils.

    The boosted regression tree model showed good predictive ability, and enabled quantification of relationships between SOCS and pedo-climatic variables (plus their interactions over the French territory. These relationship strongly depended on the land use, and more specifically differed between forest soils and cultivated soil. The total estimate of SOCS 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 SOCS distributions of France, and consequently that the previously

  12. A Ternary Polyaniline/Active Carbon/Lithium Iron Phosphate Composite as Cathode Material for Lithium Ion Battery.

    Science.gov (United States)

    Wang, Xiaohong; Zhang, Wuxing; Huang, Yunhui; Xia, Tian; Lian, Yongfu

    2016-06-01

    Lithium iron phosphate (LiFePO4) has been evaluated as the most promising cathode material for the next generation lithium-ion batteries because of its high operating voltage, good cycle performance, low cost, and environmentally friendly safety. However, pure LiFePO4 shows poor reversible capacity and charge/discharge performance at high current density. Many methods including optimization of particle size, introduction of coating carbon and conductive polymer, and the doping of metal and halogen ions have been developed to improve its electrochemical performance. In this study, conductive polymer polyaniline (PANI), active carbon and LiFePO4 (C-LFP/PANI) composite cathodes were successfully prepared by chemical oxidation method. Electrochemical performance shows that a remarkable improvement in capacity and rate performance can be achieved in the C-LFP/PANI composite cathodes with an addition of HCI. In comparison with C-LFP cathode, the C-LFP/PANI doped with HCl composite exhibits ca. 15% and 26% capacity enhancement at 0.2 C and 10 C, respectively. PMID:27427742

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

    Directory of Open Access Journals (Sweden)

    A. W. Dale

    2014-09-01

    Full Text Available 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.

  14. Model Establishment for Simulating Soil Organic Carbon Dynamics

    Institute of Scientific and Technical Information of China (English)

    HUANG Yao; LIU Shi-liang; SHEN Qi-rong; ZONG Liang-gang

    2002-01-01

    Assuming that decomposition of organic matter in soils follows the first-order kinetics reaction,a computer model was developed to simulate soil organic matter dynamics. Organic matter in soils is divided up into two parts that include incorporated organic carbon from crop residues or other organic fertilizer and soil intrinsic carbon. The incorporated organic carbon was assumed to consist of two components, labile-C and resistant-C. The model was represented by a differential equation of dCi/dt = Ki× fT × fw × fs × Ci ( i = l,r, S ) and an integral equation of Cit = Cio × EXP ( Ki X fT X fw X fs X t ). Effect of soil parameters of temperature, moisture and texture on the decomposition was functioned by the fT, fw and fs, respectively.Data from laboratory incubation experiments were used to determine the first-order decay rate Ki and the fraction of labile-C of crop residues by employing a nonlinear method. The values of K for the components of labile-C and resistant-C and the soil intrinsic carbon were evaluated to be 0. 025,0. 080 × 10-2 and 0. 065 ×10-3d-1, respectively. The labile-C fraction of wheat straw, wheat roots, rice straw and rice roots were0.50, 0.25, 0.40 and 0.20, respectively. These values are related to the initial residue carbon-to-nitrogen ratio ( C/N) and lignin content.

  15. 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...

  16. Evidence for a small bacterial contribution to sedimentary organic carbon

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hartgers, W.A.; Requejo, A.G.; Allan, J.; Hayes, J.M.; Leeuw, J.W. de

    1994-01-01

    Because their molecular signatures are often prominent in extracts of sediments, bacteria are thought to be important contributors to petroleum source beds. It has been shown recently, however, that abundances of biomarkers do not always reflect relative contributions to sedimentary organic carbon (

  17. Dynamics of dissolved organic carbon in the northwestern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.; Rajendran, A.; Somasundar, K.; Haake, B.; Jenisch, A.; Shuo, Z.; Ittekkot, V.; Desai, B.N.

    in the conversion of detrital 0304-4203/90/$03.50 © 1990 -- Elsevier Science Publishers B.V. 300 M. DILEEP KUMAR ET AL. matter into inorganic carbon dioxide and plays a pivotal role in food chain processes by becoming a substrate for micro-organisms. The nature...

  18. 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 preserving effect of fine particle.

  19. 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 patte

  20. Ethanol production from crop residues and soil organic carbon

    NARCIS (Netherlands)

    L. Reijnders

    2008-01-01

    In decision making about the use of residues from annual crops for ethanol production, alternative applications of these residues should be considered. Especially important is the use of such residues for stabilizing and increasing levels of soil organic carbon. Such alternative use leads to a limit

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu Yanyi; Liu Dawei; Zhang Qifeng [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Yu Danmei [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Liu Jun [Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, WA 99352 (United States); Cao Guozhong, E-mail: gzcao@u.washington.ed [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States)

    2011-02-01

    This paper reports sol-gel derived nanostructured LiFePO{sub 4}/carbon nanocomposite film cathodes exhibiting enhanced electrochemical properties and cyclic stabilities. LiFePO{sub 4}/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 LiFePO{sub 4}/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 LiFePO{sub 4} 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-02-01

    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.

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

    International Nuclear Information System (INIS)

    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.

  4. Spatial distribution of soil organic carbon stocks in France

    Science.gov (United States)

    Martin, M. P.; Wattenbach, M.; Smith, P.; Meersmans, J.; Jolivet, C.; Boulonne, L.; Arrouays, D.

    2011-05-01

    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 previously published approach at 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. Conversion of organic carbon in the decomposable organic wastes in anaerobic lysimeters under different temperatures

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The quantitative fractions of conversion of organic carbon in the decomposable organic wastes with initial moisture of 70% sorted from municipal solid wastes(MSW) in lysimeters into biogas, leachate and solid residue were characterized, under temperatures of 25, 30 and 41℃, respectively, and circulation of leachate generated within the lysimeters. It is found that 27% of organic carbon in the wastes are conversed into gases, 0.8% into leachate, and the other 72% remained in the decomposable solid residues, after 180 days' degradation at 41℃. Higher temperature will lead to more rapid degradation and result to higher conversion of the organic carbon to biogas and lower to both solid residues and leachate, while the pollutant concentrations in leachate will be lower at a higher temperature and the values of COD are quite consistent with TOC.

  7. Conversion of organic carbon in the decomposable organic wastes in anaerobic lysimeters under different temperatures.

    Science.gov (United States)

    Zhao, You-Cai; Wang, Luo-Chun

    2003-05-01

    The quantitative fractions of conversion of organic carbon in the decomposable organic wastes with initial moisture of 70% sorted from municipal solid wastes (MSW) in lysimeters into biogas, leachate and solid residue were characterized, under temperatures of 25, 30 and 41 degrees C, respectively, and circulation of leachate generated within the lysimeter. It is found that 27% of organic carbon in the wastes are conversed into gases, 0.8% into leachate, and the other 72% remained in the decomposable solid residues, after 180 days' degradation at 41 degrees C. Higher temperature will lead to more rapid degradation and result to higher conversion of the organic carbon to biogas and lower to both solid residues and leachate, while the pollutant concentrations in leachate will be lower at a higher temperature and the values of COD are quite consistent with TOC. PMID:12938979

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

    International Nuclear Information System (INIS)

    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−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

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

    Science.gov (United States)

    Yang, Chao; Mo, Haodao; Zang, Limin; Qiu, Jianhui; Sakai, Eiichi; Wu, Xueli

    2014-09-01

    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-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.

  10. 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.

  11. Soil Organic Carbon Loss: An Overlooked Factor in the Carbon Sequestration Potential of Enhanced Mineral Weathering

    Science.gov (United States)

    Dietzen, Christiana; Harrison, Robert

    2016-04-01

    Weathering of silicate minerals regulates the global carbon cycle on geologic timescales. Several authors have proposed that applying finely ground silicate minerals to soils, where organic acids would enhance the rate of weathering, could increase carbon uptake and mitigate anthropogenic CO2 emissions. Silicate minerals such as olivine could replace lime, which is commonly used to remediate soil acidification, thereby sequestering CO2 while achieving the same increase in soil pH. However, the effect of adding this material on soil organic matter, the largest terrestrial pool of carbon, has yet to be considered. Microbial biomass and respiration have been observed to increase with decreasing acidity, but it is unclear how long the effect lasts. If the addition of silicate minerals promotes the loss of soil organic carbon through decomposition, it could significantly reduce the efficiency of this process or even create a net carbon source. However, it is possible that this initial flush of microbial activity may be compensated for by additional organic matter inputs to soil pools due to increases in plant productivity under less acidic conditions. This study aimed to examine the effects of olivine amendments on soil CO2 flux. A liming treatment representative of typical agricultural practices was also included for comparison. Samples from two highly acidic soils were split into groups amended with olivine or lime and a control group. These samples were incubated at 22°C and constant soil moisture in jars with airtight septa lids. Gas samples were extracted periodically over the course of 2 months and change in headspace CO2 concentration was determined. The effects of enhanced mineral weathering on soil organic matter have yet to be addressed by those promoting this method of carbon sequestration. This project provides the first data on the potential effects of enhanced mineral weathering in the soil environment on soil organic carbon pools.

  12. Dysregulation of phosphate metabolism and conditions associated with phosphate toxicity

    OpenAIRE

    Brown, Ronald B; Razzaque, Mohammed S

    2015-01-01

    Phosphate homeostasis is coordinated and regulated by complex cross-organ talk through delicate hormonal networks. Parathyroid hormone (PTH), secreted in response to low serum calcium, has an important role in maintaining phosphate homeostasis by influencing renal synthesis of 1,25-dihydroxyvitamin D, thereby increasing intestinal phosphate absorption. Moreover, PTH can increase phosphate efflux from bone and contribute to renal phosphate homeostasis through phosphaturic effects. In addition,...

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

    Science.gov (United States)

    Liu, Shou-jie; Li, He-jun; Zhang, Lei-lei; Feng, Lei; Yao, Pei

    2015-12-01

    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.

  14. Fossil organic carbon in Siberian Yedoma and thermokarst deposits

    Science.gov (United States)

    Strauss, J.; Schirrmeister, L.; Wetterich, S.

    2011-12-01

    During the late Quaternary, a large pool of organic carbon accumulated in the ice-rich syngenetic frozen deposits and soils preserved in the arctic and subarctic permafrost zone. Because of the potential release of organic carbon from degrading permafrost, the organic-matter (OM) inventory in Yedoma deposits and its degradation features are relevant to current concerns about the effects of global warming. In this context, it is essential to improve the understanding permafrost-stored OM composition and availability. The objective of this study is to develop an approach of OM quantification in frozen deposits including OM quality estimation. We analyzed OM characteristics like total organic carbon content, stable carbon isotopes and carbon-nitrogen ratios. Moreover, lipid biomarkers (alkanes, fatty acids and glycerol dialkyl glycerol tetraether) and sediment parameters like grain size and bulk density of Yedoma and thermokarst deposits exposed at Duvanny Yar (lower Kolyma River, Siberia) and the west coast of Buor Khaya Peninsula (Laptev Sea, Siberia) were studied. With the biomarker approach it is possible to distinguish deposits which were accumulated and frozen during the Pleistocene and Holocene. Biomarker indices, like the compound specific index, average chain length and tetraether characteristics supply feasible results for past permafrost environments. Late Pleistocene biomarker records indicate cold conditions during the growth/summer period for the late Pleistocene and generally low degradation of the stored OM. In contrast, Holocene thermokarst deposits indicate warmer conditions. The averaged volumetric OM content of the studied Yedoma and thermokarst deposits are greater than 10 kg/m^3 and do not exceed 30 kg/m^3. Given that Yedoma deposits accumulated at relatively fast rates and at low temperatures, the OM underwent a short time of decomposition before it was incorporated into a permanently-frozen state. Consequently, such deposits contain a labile

  15. 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.

  16. Assimilable organic carbon generation from algogenic organic matter in drinking water

    OpenAIRE

    Kim, Ji-Hoon; Kim, Young-Ju; QURESHI, Tahir Irman

    2011-01-01

    A study of assimilable organic carbon (AOC) derived from algogenic organic matter in different drinking water resources was conducted. Seasonal changes in the concentration of AOC at Kamafusa Dam were dependent on the algal cell numbers. Variations in AOC concentrations were found to be more reliant on the AOC-P17 component than the AOC-NOX component. The algal culture experiment showed that extracellular organic matter (EOM) released during the growth of Phormidium tenue in M-11 cu...

  17. Fluorescence characteristics of water soluble organic carbon in eastern China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fluorescence excitation and average molecular weight of 46 water soluble organic matter (WSOC) samples extracted from 20 soil types in eastern China were determined. It was found all samples shared similar spectroscopy. A good linear relationship existed between total organic carbon and excitation in the range of 350 to 450 nm though the content of organic carbon and pH of the samples vary in a wide range. No significant correlation between relative excitation intensity and average molecular weight of WSOC and FA was found, but the partial correlation became significant with pH as the controlling factor for WSOC samples. The relative excitation intensity showed a general trend of increasing from south to north in the study area. The pH value might play an important role in regulating the fluorescent spatial variation of WSOC.

  18. Study on the Corrosion Inhibition Characteristics of Carbon Steel by Sodium Phosphate and Sodium Nitrite

    International Nuclear Information System (INIS)

    Sodium nitrite is widely used as one of the popular corrosion inhibitors for the protection of ferrous metal in closed cooling water system, such as a diesel engine and a chiller. The optimum treatment conditions are studied through laboratory tests using linear polarization resistance (LPR) technique. Corrosion rate of the carbon steel electrode could be maintained less than 2.5x10-3 mmpy in the test condition of 500 ppm as NO2-, 200 ppm as CT, 70 .deg. C and pH 6.8. The pH control is confirmed not to be an important factor in the protection of carbon steel by sodium nitrite inhibitor. The addition of tolyltriazole was needed for the protection of the copper alloy in the sodium nitrite treatment system

  19. Prediction of soil organic carbon concentration and soil bulk density of mineral soils for soil organic carbon stock estimation

    Science.gov (United States)

    Putku, Elsa; Astover, Alar; Ritz, Christian

    2016-04-01

    Soil monitoring networks provide a powerful base for estimating and predicting nation's soil status in many aspects. The datasets of soil monitoring are often hierarchically structured demanding sophisticated data analyzing methods. The National Soil Monitoring of Estonia was based on a hierarchical data sampling scheme as each of the monitoring site was divided into four transects with 10 sampling points on each transect. We hypothesized that the hierarchical structure in Estonian Soil Monitoring network data requires a multi-level mixed model approach to achieve good prediction accuracy of soil properties. We used this database to predict soil bulk density and soil organic carbon concentration of mineral soils in arable land using different statistical methods: median approach, linear regression and mixed model; additionally, random forests for SOC concentration. We compared the prediction results and selected the model with the best prediction accuracy to estimate soil organic carbon stock. The mixed model approach achieved the best prediction accuracy in both soil organic carbon (RMSE 0.22%) and bulk density (RMSE 0.09 g cm-3) prediction. Other considered methods under- or overestimated higher and lower values of soil parameters. Thus, using these predictions we calculated the soil organic carbon stock of mineral arable soils and applied the model to a specific case of Tartu County in Estonia. Average estimated SOC stock of Tartu County is 54.8 t C ha-1 and total topsoil SOC stock 1.8 Tg in humus horizon.

  20. Adsorption of dissolved natural organic matter by modified activated carbons.

    Science.gov (United States)

    Cheng, Wei; Dastgheib, Seyed A; Karanfil, Tanju

    2005-06-01

    Adsorption of dissolved natural organic matter (DOM) by virgin and modified granular activated carbons (GACs) was studied. DOM samples were obtained from two water treatment plants before (i.e., raw water) and after coagulation/flocculation/sedimentation processes (i.e., treated water). A granular activated carbon (GAC) was modified by high temperature helium or ammonia treatment, or iron impregnation followed by high temperature ammonia treatment. Two activated carbon fibers (ACFs) were also used, with no modification, to examine the effect of carbon porosity on DOM adsorption. Size exclusion chromatography (SEC) and specific ultraviolet absorbance (SUVA(254)) were employed to characterize the DOMs before and after adsorption. Iron-impregnated (HDFe) and ammonia-treated (HDN) activated carbons showed significantly higher DOM uptakes than the virgin GAC. The enhanced DOM uptake by HDFe was due to the presence of iron species on the carbon surface. The higher uptake of HDN was attributed to the enlarged carbon pores and basic surface created during ammonia treatment. The SEC and SUVA(254) results showed no specific selectivity in the removal of different DOM components as a result of carbon modification. The removal of DOM from both raw and treated waters was negligible by ACF10, having 96% of its surface area in pores smaller than 1 nm. Small molecular weight (MW) DOM components were preferentially removed by ACF20H, having 33% of its surface area in 1--3 nm pores. DOM components with MWs larger than 1600, 2000, and 2700 Da of Charleston raw, Charleston-treated, and Spartanburg-treated waters, respectively, were excluded from the pores of ACF20H. In contrast to carbon fibers, DOM components from entire MW range were removed from waters by virgin and modified GACs. PMID:15927230

  1. 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.

  2. 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.)

  3. Soil Organic Carbon and Labile Carbon Along a Precipitation Gradient and Their Responses to Some Environmental Changes

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-Ping; ZHOU Guang-Sheng; GAO Su-Hua; GUO Jian-Ping

    2005-01-01

    Based on data from a field survey in 2001 along the Northeast China transect (NECT), a precipitation gradient,and a short-term simulation experiment under ambient CO2 of 350 μmol mol-1 and doubled CO2 of 700 μmol mol-1 with different soil moisture contents of 30%-45%, 45%-60%, and 60%-80% soil water holding capacity, the distribution of soil organic carbon and labile carbon along the NECT, their relationships with precipitation and their responses to CO2 enrichment and soil moisture changes were analyzed. The results indicated that the soil labile carbon along the gradient was significantly related to soil organic carbon (r = 0.993, P < 0.001). The soil labile carbon decreased more rapidly with depth than organic carbon. The soil organic and labile carbon along the gradient decreased with decrease in longitude in both the topsoils and subsoils, and the coefficient of variation for the labile carbon was greater than that for the organic carbon. Both the soil organic carbon and labile carbon had significant linear relationships with precipitation,with the correlation coefficient of soil organic carbon being lower (0.677 at P <0.001) than that of soil labile carbon (0.712 at P < 0.001). In the simulation experiment with doubled and ambient CO2 and different moisture contents, the coefficient of variation for soil organic carbon was only 1.3%, while for soil labile carbon it was 29.7%. With doubled CO2 concentration (700μmol mol-1), soil labile carbon decreased significantly at 45% to 60% of soil moisture content. These indicated that soil labile carbon was relatively more sensitive to environmental changes than soil organic carbon.

  4. Effect of biostimulation on biodegradation of dissolved organic carbon in biological granular activated carbon filters

    Directory of Open Access Journals (Sweden)

    K. Tihomirova

    2012-03-01

    Full Text Available The addition of labile organic carbon (LOC to enhance the biodegradation rate of dissolved organic carbon (DOC in biological columns was studied. Acetate standard solution (NaAc and LB (Luria Bertrani medium were used as LOC as biostimulants in glass column system used for measurements of biodegradable dissolved organic carbon (BDOC. The addition of LOC related with the increase of total DOC in sample. The concentration of BDOC increased up to 7 and 5 times and was utilized after 24 min. contact time. The biodegradation rate constant was increased at least 8 times during adaptation-biostimulation period. There was a strong positive correlation between the biodegradation rate constant and the concentration of BDOC. Biostimulation period ranged from 24 to 53 h for NaAc biostimulant and from 20 to 168 h for LB. The study has shown that LOC could be used as stimulator to enhance the biodegradation rate of DOC during biofiltration.

  5. Chemical and carbon isotopic composition of dissolved organic carbon in a regional confined methanogenic aquifer

    Science.gov (United States)

    Aravena, R.; Wassenaar, L.I.; Spiker, E. C.

    2004-01-01

    This study demonstrates the advantage of a combined use of chemical and isotopic tools to understand the dissolved organic carbon (DOC) cycle in a regional confined methanogenic aquifer. DOC concentration and carbon isotopic data demonstrate that the soil zone is a primary carbon source of groundwater DOC in areas close to recharge zones. An in-situ DOC source linked to organic rich sediments present in the aquifer matrix is controlling the DOC pool in the central part of the groundwater flow system. DOC fractions, 13C-NMR on fulvic acids and 14C data on DOC and CH4 support the hypothesis that the in-situ DOC source is a terrestrial organic matter and discard the Ordovician bedrock as a source of DOC. ?? 2004 Taylor and Francis Ltd.

  6. Modelling soil organic carbon in Danish agricultural soils suggests low potential for future carbon sequestration

    DEFF Research Database (Denmark)

    Taghizadeh-Toosi, Arezoo; Olesen, Jørgen Eivind

    2016-01-01

    over the same period of time. The results of the C-TOOL simulations demonstrated that application of organic manure, use of cover crop, and converting the croplands to grassland had the potential to increase SOC in Danish mineral soils. The simulated data also suggested that C-TOOL gave a reasonably......Soil organic carbon (SOC) is in active exchange with the atmosphere. The amount of organic carbon (OC) input into the soil and SOC turnover rate are important for predicting the carbon (C) sequestration potential of soils subject to changes in land-use and climate. The C-TOOL model was developed...... to simulate the dynamics of SOC storage on medium- to long-term trends in the whole soil profile (0–100 cm), and was used to compare SOC changes under typical Danish farming conditions for two sites in Denmark having the greatest possible temperature differences for the period 1986 and 2012. For this purpose...

  7. Phosphate salts

    Science.gov (United States)

    ... reduces the body's ability to absorb phosphate and iron. To avoid this interaction, phosphate should be taken at least 2 hours before or after taking iron.MagnesiumPhosphate can combine with magnesium. This reduces ... phosphate and magnesium. To avoid this interaction, phosphate should ...

  8. Modeling stable isotope and organic carbon in hillslope stormflow

    Science.gov (United States)

    Dusek, Jaromir; Vogel, Tomas; Dohnal, Michal; Marx, Anne; Jankovec, Jakub; Sanda, Martin; Votrubova, Jana; Barth, Johannes A. C.; Cislerova, Milena

    2016-04-01

    Reliable prediction of water movement and fluxes of dissolved substances (such as stable isotopes and organic carbon) at both the hillslope and the catchment scales remains a challenge due to complex boundary conditions and soil spatial heterogeneity. In addition, microbially mediated transformations of dissolved organic carbon (DOC) are known to affect balance of DOC in soils, hence the transformations need to be included in a conceptual model of a DOC transport. So far, only few studies utilized stable isotope information in modeling and even fewer linked dissolved carbon fluxes to mixing and/or transport models. In this study, stormflow dynamics of oxygen-18 isotope and dissolved organic carbon was analyzed using a physically based modeling approach. One-dimensional dual-continuum vertical flow and transport model, based on Richards and advection-dispersion equations, was used to simulate the subsurface transport processes in a forest soil during several observed rainfall-runoff episodes. The transport of heat in the soil profile was described by conduction-advection equation. Water flow and transport of solutes and heat were assumed to take place in two mutually communicating porous domains, the soil matrix and the network of preferential pathways. The rate of microbial transformations of DOC was assumed to depend on soil water content and soil temperature. Oxygen-18 and dissolved organic carbon concentrations were observed in soil pore water, hillslope stormflow (collected in the experimental hillslope trench), and stream discharge (at the catchment outlet). The modeling was used to analyze the transformation of input solute signals into output hillslope signals observed in the trench stormflow. Signatures of oxygen-18 isotope in hillslope stormflow as well as isotope concentration in soil pore water were predicted reasonably well. Due to complex nature of microbial transformations, prediction of DOC rate and transport was associated with a high uncertainty.

  9. Linking soil organic carbon pools with measured fractions

    Science.gov (United States)

    Herbst, M.; Welp, G.; Amelung, W.; Weihermueller, L.; Vereecken, H.

    2012-04-01

    Soil organic carbon (SOC) pools play an important role for the understanding and the predictive modelling of heterotrophic respiration. One of the major issues concerning model carbon pools is their purely conceptual definition. They are just defined by a turnover rate. Despite some attempts to link the conceptual model pools to measurable SOC fractions, this challenge basically remains unsolved. In this study we introduce an empirical approach to link the model pools of RothC with measured particulate organic matter fractions and an inert carbon fraction. For 63 topsoil samples from arable fields a mid-infrared spectroscopic approach was applied to determine the carbon contents in three particle-size fractions (POM1: 2000-250 μm, POM2: 250-53 μm and POM3: 53-20 μm) and a black carbon fraction. To provide the model pools for the 63 sampling sites RothC was run into equilibrium based on site-specific soil properties and meteorological data ranging from 1961 to present. It was possible to prove a link between soil organic matter fractions and pools of RothC. The coefficient of correlation between fPOM (POM1+POM2) and the resistant plant material (RPM) pool was 0.73. However, establishing multiple linear regressions based on all measured fractions instead of using just the fraction between 2000 and 53 μm significantly improved the prediction of the RPM pool. The resultant adjusted coefficient of determination using all fractions to predict RPM was 0.94. A stepwise regression algorithm based on the Akaike information criterion retained all measured fractions in the regression, pointing to the relevance of all fractions. The same was observed when linking the humic fraction of RothC (HUM) to the measured humic fractions, which were calculated as the difference between TOC and the sum of particulate and black carbon. The adjusted R2 was 0.84. Using again all measured fractions as explanatory variables for HUM increased the R2 to 0.99. From these observations we

  10. The Decomposition of Carbonates and Organics on Mars

    Science.gov (United States)

    Quinn, Richard C.; Zent, Aaron; McKay, Chris; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The return and analysis of pristine material that is relict of a putative period of chemical evolution is a fumdamental goal of the exobiological exploration of Mars. In order to accomplish this objective, it is desirable to find oxidant-free regions where pristine material can be accessed at the shallowest possible depth (ideally directly from the surface). The objective of our ongoing research is to understand the spatial and temporal distribution of oxidants in the martian regolith and the redox chemistry of the soil; in effect to understand the chemical mechanisms and kinetics relating to the in-situ destruction of organics and the formation of the reactive species responsible for the Viking biology results. In this work, we report on experimental studies of oxidizing processes that may contribute to carbonate and organic degradation on Mars. Organic molecules directly exposed to solar UV may decomposed either directly into CO2, or into more volatile organic fragments. Organic macromolecules not directly exposed to high UV flux are most likely to be affected by atmospheric oxidants which can diffuse to their surfaces. The oxidizing processes examined include: gas-phase oxidants, UV photolysis, and UV-assisted heterogeneous catalysis. For example, assuming a meteroritic infall rate of 4 x 10(exp -4) g/m^2yr (Flynn and McKay 1990) and a flux of organic carbon of 2 x 10(exp -5) g/m^2yr, laboratory measurements of the UV-assisted decomposition of benzenehexacarboxylic acid (mellitic acid, a likely intermediate of kerogen oxidation), indicate its decomposition rate on Mars would exceed the total flux of organic carbon to the planet by over four orders of magnitude. Our measurements indicate that although the decomposition temperature of kerogens in some cases exceeds the temperature limit of the Viking GCMS, it is unlikely kerogens or their decomposition intermediates were present at the Viking landings sites at levels above the GCMS detection limits.

  11. 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

  12. An experimental study on the effects of nutrient enrichment on organic carbon storage in western Pacific oligotrophic gyre

    Directory of Open Access Journals (Sweden)

    J. Liu

    2014-02-01

    Full Text Available Carbon sequestration in the ocean is of great concern with respect to the mitigation of global warming. How to hold the fixed organic carbon in the presence of tremendous heterotrophic microorganisms in marine environments is the central issue. We have previously hypothesized that excessive nutrients would ultimately decrease the storage of organic carbon in marine environments. To test it out, a series of in situ nutrient enrichment incubation experiments were conducted at a site (17.59° N, 127.00° E within the Western Pacific oligotrophic gyre. Five treatments were employed: glucose or algal exudation organic material (EOM and nitrate and phosphate were added alone or in combination to approximate final concentrations of 10 μmol C kg−1, 1 μmol N kg−1 and 0.11 μmol P kg−1 respectively. The results showed that the dissolved organic carbon (DOC consumption rates and bacterial community specific growth rates were enhanced by inorganic nutrients enrichment treatments during the initial 48 h incubation. At the end of 14 days incubation, about 1/3 (average 3.29 μmol C kg−1 more organic carbon was respired from the glucose enriched incubation with addition of inorganic nutrients compared to that without addition of inorganic nutrients. In the case no essential nutrients were available, even glucose could not be efficiently used by bacteria and thus remained in the environment. These results suggest that repletion of inorganic nutrients has negative impacts on carbon preservation, presumably due to elevated nutrient-stimulated bacterial metabolism and respiration, which is meaningful for potential coastal water management and worth for further studies.

  13. An experimental study on the effects of nutrient enrichment on organic carbon storage in western Pacific oligotrophic gyre

    Science.gov (United States)

    Liu, J.; Jiao, N.; Tang, K.

    2014-02-01

    Carbon sequestration in the ocean is of great concern with respect to the mitigation of global warming. How to hold the fixed organic carbon in the presence of tremendous heterotrophic microorganisms in marine environments is the central issue. We have previously hypothesized that excessive nutrients would ultimately decrease the storage of organic carbon in marine environments. To test it out, a series of in situ nutrient enrichment incubation experiments were conducted at a site (17.59° N, 127.00° E) within the Western Pacific oligotrophic gyre. Five treatments were employed: glucose or algal exudation organic material (EOM) and nitrate and phosphate were added alone or in combination to approximate final concentrations of 10 μmol C kg-1, 1 μmol N kg-1 and 0.11 μmol P kg-1 respectively. The results showed that the dissolved organic carbon (DOC) consumption rates and bacterial community specific growth rates were enhanced by inorganic nutrients enrichment treatments during the initial 48 h incubation. At the end of 14 days incubation, about 1/3 (average 3.29 μmol C kg-1) more organic carbon was respired from the glucose enriched incubation with addition of inorganic nutrients compared to that without addition of inorganic nutrients. In the case no essential nutrients were available, even glucose could not be efficiently used by bacteria and thus remained in the environment. These results suggest that repletion of inorganic nutrients has negative impacts on carbon preservation, presumably due to elevated nutrient-stimulated bacterial metabolism and respiration, which is meaningful for potential coastal water management and worth for further studies.

  14. The evolution of the marine phosphate reservoir.

    Science.gov (United States)

    Planavsky, Noah J; Rouxel, Olivier J; Bekker, Andrey; Lalonde, Stefan V; Konhauser, Kurt O; Reinhard, Christopher T; Lyons, Timothy W

    2010-10-28

    Phosphorus is a biolimiting nutrient that has an important role in regulating the burial of organic matter and the redox state of the ocean-atmosphere system. The ratio of phosphorus to iron in iron-oxide-rich sedimentary rocks can be used to track dissolved phosphate concentrations if the dissolved silica concentration of sea water is estimated. Here we present iron and phosphorus concentration ratios from distal hydrothermal sediments and iron formations through time to study the evolution of the marine phosphate reservoir. The data suggest that phosphate concentrations have been relatively constant over the Phanerozoic eon, the past 542 million years (Myr) of Earth's history. In contrast, phosphate concentrations seem to have been elevated in Precambrian oceans. Specifically, there is a peak in phosphorus-to-iron ratios in Neoproterozoic iron formations dating from ∼750 to ∼635 Myr ago, indicating unusually high dissolved phosphate concentrations in the aftermath of widespread, low-latitude 'snowball Earth' glaciations. An enhanced postglacial phosphate flux would have caused high rates of primary productivity and organic carbon burial and a transition to more oxidizing conditions in the ocean and atmosphere. The snowball Earth glaciations and Neoproterozoic oxidation are both suggested as triggers for the evolution and radiation of metazoans. We propose that these two factors are intimately linked; a glacially induced nutrient surplus could have led to an increase in atmospheric oxygen, paving the way for the rise of metazoan life.

  15. Axially aligned organic fibers and amorphous calcium phosphate form the claws of a terrestrial isopod (Crustacea).

    Science.gov (United States)

    Vittori, Miloš; Srot, Vesna; Žagar, Kristina; Bussmann, Birgit; van Aken, Peter A; Čeh, Miran; Štrus, Jasna

    2016-08-01

    Skeletal elements that are exposed to heavy mechanical loads may provide important insights into the evolutionary solutions to mechanical challenges. We analyzed the microscopic architecture of dactylus claws in the woodlice Porcellio scaber and correlated these observations with analyses of the claws' mineral composition with energy dispersive X-ray spectrometry (EDX), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED). Extraordinarily, amorphous calcium phosphate is the predominant mineral in the claw endocuticle. Unlike the strongly calcified exocuticle of the dactylus base, the claw exocuticle is devoid of mineral and is highly brominated. The architecture of the dactylus claw cuticle is drastically different from that of other parts of the exoskeleton. In contrast to the quasi-isotropic structure with chitin-protein fibers oriented in multiple directions, characteristic of the arthropod exoskeleton, the chitin-protein fibers and mineral components in the endocuticle of P. scaber claws are exclusively axially oriented. Taken together, these characteristics suggest that the claw cuticle is highly structurally anisotropic and fracture resistant and can be explained as adaptations to predominant axial loading of the thin, elongated claws. The nanoscale architecture of the isopod claw may inspire technological solutions in the design of durable machine elements subjected to heavy loading and wear.

  16. Axially aligned organic fibers and amorphous calcium phosphate form the claws of a terrestrial isopod (Crustacea).

    Science.gov (United States)

    Vittori, Miloš; Srot, Vesna; Žagar, Kristina; Bussmann, Birgit; van Aken, Peter A; Čeh, Miran; Štrus, Jasna

    2016-08-01

    Skeletal elements that are exposed to heavy mechanical loads may provide important insights into the evolutionary solutions to mechanical challenges. We analyzed the microscopic architecture of dactylus claws in the woodlice Porcellio scaber and correlated these observations with analyses of the claws' mineral composition with energy dispersive X-ray spectrometry (EDX), electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAED). Extraordinarily, amorphous calcium phosphate is the predominant mineral in the claw endocuticle. Unlike the strongly calcified exocuticle of the dactylus base, the claw exocuticle is devoid of mineral and is highly brominated. The architecture of the dactylus claw cuticle is drastically different from that of other parts of the exoskeleton. In contrast to the quasi-isotropic structure with chitin-protein fibers oriented in multiple directions, characteristic of the arthropod exoskeleton, the chitin-protein fibers and mineral components in the endocuticle of P. scaber claws are exclusively axially oriented. Taken together, these characteristics suggest that the claw cuticle is highly structurally anisotropic and fracture resistant and can be explained as adaptations to predominant axial loading of the thin, elongated claws. The nanoscale architecture of the isopod claw may inspire technological solutions in the design of durable machine elements subjected to heavy loading and wear. PMID:27320700

  17. Soil organic carbon pools in olive groves of different age

    Science.gov (United States)

    Massaccesi, Luisa; De Feudis, Mauro; Nasini, Luigi; Regni, Luca; D'Ascoli, Rosaria; Castaldi, Simona; Proietti, Primo; Agnelli, Alberto

    2016-04-01

    In the last years, the practices which favor the increase of soil organic carbon in the agroecosystem have been widely studied because of their influence on the reduction of atmospheric CO2 (Lal, 1993; Schlesinger, 2000). The accumulation of the organic carbon into the soil depends to a great extent upon climate and pedological properties (Burke et al., 1989; Miller et al., 1994), although in the agricultural soils the cultivation system also plays a key role. The olive grove might potentially represent a relevant land use to improve C sequestration in soil, but there are few data available to support this hypothesis. In a study site located in central Italy (Deruta, PG), we analyzed the soil organic carbon (SOC) pools in two olive groves of different age (7 and 30 years) and, as control, in a site adjacent to the groves cropped with cereals for at least 30 years. With the aim to isolate and quantify the active, intermediate and passive functional SOC pools in the olive groves and in the control, we used a combined physical and chemical fractionation method (Zimmermann et al., 2007). The main results shown that the total organic carbon content in the Ap horizons was the highest in the 30-years-old olive grove, followed by the 7-years-old olive grove, and then by the control soil. The content of active C, in form of particulate organic matter (POM) and water soluble organic matter (WEOM), was greater in the olive grove compared to the control soil and increase with the age of the grove. About the amount of C in the intermediate and passive pools, no significant differences were found among the olive groves and the control. These preliminary results indicated that the greater total organic C content occurred in the 30-year-old olive grove with respect to the 7-years-old grove and the control, has to be ascribed to the greater content of active organic matter (POM and WEOM), and not to the accumulation in soil of organic C in a more stabilised form.

  18. Organic nutrient enrichment in the oligotrophic ocean: Impacts on remineralization, carbon sequestration, and community structure

    Science.gov (United States)

    Mackey, K. R.; Paytan, A.; Post, A. F.

    2007-12-01

    In oligotrophic seas where inorganic nitrogen (N) and phosphorus (P) are below the limits of detection, organic forms of these nutrients may constitute greater than 90% of the total N and P in the euphotic zone. The combined enzymatic activity of phytoplankton and heterotrophic bacteria determines the rate of nutrient remineralization, thereby influencing phytoplankton growth rates and carbon sequestration in these regions. In this study we investigated the effects of fertilization with ammonium (NH4), nitrate (NO3), nitrite (NO2), and phosphate (PO4) as well as various forms of organic N (urea, glycine) and P (deoxyribonucleic acid, 2- aminoethyl phosphonic acid, phytic acid) on the growth and taxonomic composition of the phytoplankton community in the Gulf of Aqaba, Red Sea. The impacts of these changes on nutrient cycling and biological assimilation were also assessed. Organic N additions led to phytoplankton growth when given together with PO4, yielding 2-3 fold increases in chlorophyll a (Chl a) and cell density relative to initial levels. Moreover, our results show that addition of NH4 or NO3 led to accumulation of extra-cellular NO2, suggesting that incomplete assimilatory reduction of NO3 by phytoplankton as well as chemoautotrophic oxidation of NH4 by ammonium oxidizing microbes contributed to NO2 formation. These findings conflict with earlier studies in the Gulf that attributed NO2 formation solely to the phytoplankton community. Organic P additions also led to 2-3 fold increases in Chl a and cell density relative to initial levels when given together with NH4 and NO3. Compared to other P additions, DNA led to the rapid accumulation of extra-cellular PO4, indicating substantial nucleotidase activity in excess of the amount needed to meet phytoplankton growth requirements. These results show the importance and interconnectivity of phytoplankton and heterotrophic bacteria communities in contributing to nutrient cycling and carbon sequestration in

  19. Erosion of Organic Carbon from Permafrost Zones in the Arctic as a Geological Carbon Dioxide Sink

    Science.gov (United States)

    Hilton, R. G.; Galy, V.; Gaillardet, J.; Dellinger, M.; Bryant, C.; O'Regan, M.; Gröcke, D. R.; Coxall, H.; Bouchez, J.; Calmels, D.

    2015-12-01

    Soils of the northern high latitudes store carbon over millennial timescales and contain almost double the carbon stock of the atmosphere. The exposure and decomposition of aged organic matter in these soils is a carbon dioxide (CO2) source to the atmosphere. Permafrost thaw over the coming century may result in a significant CO2 release. However, some of this soil organic carbon in permafrost zones can be eroded and input to rivers. If it escapes degradation during river transport and is buried in ocean sediments, it instead contributes to a longer-term (>104 yr), geological CO2sink. Despite this recognition, the erosional flux and fate of particulate organic carbon (POC) in large rivers draining permafrost zones remains poorly constrained. We quantify POC source, flux and fate in the Mackenzie River Basin, the main sediment supplier to the Arctic Ocean, using radiocarbon, stable carbon isotopes and element ratios to correct for rock-derived POC. The eroded biospheric POC has resided in the basin for millennia, with a mean radiocarbon age of 5800±800 yr. Rivers eroding continuous permafrost zones contribute the oldest biospheric POC. Based on the measured biospheric POC content and annual sediment flux, we calculate a biospheric POC flux of 2.2 (+1.3/-0.9) TgC yr-1 from the Mackenzie River to the Arctic Ocean, three times the CO2 drawdown by silicate weathering. Offshore we find evidence for efficient terrestrial carbon burial over the Holocene period. Our findings demonstrate how erosion of organic carbon-rich, high latitude soils can result in a significant geological CO2sink. We postulate that this geological CO2 sink is sensitive to climate conditions in the Arctic. The transfer can operate when high latitudes host carbon stocks in soil, and while rivers can erode and transfer sediments to the Arctic Ocean. Over the last 1Ma, the erosional transfer was likely to have been enhanced during interglacials. We propose that erosion of biospheric carbon by large

  20. 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

    2016-01-01

    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. PMID:27126606

  1. Relationship Between Development, Metabolism, and Mitochondrial Organization in 2-Cell Hamster Embryos in the Presence of Low Levels of Phosphate

    Science.gov (United States)

    Ludwig, Tenneille E.; Squirrell, Jayne M.; Palmenberg, Ann C.; Bavister, Barry D.

    2016-01-01

    The effect of low concentrations of inorganic phosphate (Pi) on development, metabolic activity, and mitochondrial organization in the same cohorts of cultured hamster embryos was evaluated. Two-cell embryos were collected from eCG-stimulated golden hamsters and cultured in HECM-10 with 0.0 (control), 1.25, 2.5, or 5.0 µM KH2PO4. Glucose utilization through the Embden-Meyerhof pathway (EMP) and tricarboxylic acid (TCA)-cycle activity were determined following 5 h of culture. Mitochondrial organization in living embryos was evaluated using multiphoton microscopy at 6 h of culture. Development was assessed at 27 h (on-time 8-cell stage) and 51 h (on-time blastocyst stage) of culture. Total cell numbers, as well as cell allocation to the trophectoderm and inner cell mass were determined for morula- and blastocyst-stage embryos. Culture with Pi did not alter TCA-cycle activity. However, culture with ≥2.5 µM Pi significantly increased (P organization was significantly (P culture medium dramatically alters embryo physiology. Additionally, although 2-cell embryos can tolerate some structural disruption without concomitant, detrimental effects on development or metabolic activity, metabolic disturbance is associated with decreased developmental competence. PMID:11717124

  2. Temperature sensitivity of decomposition of soil organic carbon fractions

    Science.gov (United States)

    Hilasvuori, Emmi; Järvenpää, Marko; Akujärvi, Anu; Arppe, Laura; Christensen, Bent T.; Fritze, Hannu; Kaasalainen, Mikko; Karhu, Kristiina; Oinonen, Markku; Palonen, Vesa; Pitkänen, Juha-Matti; Repo, Anna; Vanhala, Pekka; Liski, Jari

    2015-04-01

    Knowing the temperature sensitivity of soil organic matter (SOM) decomposition is important for estimating the release of carbon from soil to the atmosphere in response to global warming. This temperature sensitivity is known relatively well for the most labile SOM fractions but still quite poorly for more recalcitrant fractions that represent the great majority of SOM. We report results for the temperature sensitivity of various SOM fractions in two different experiments in which we utilized natural abundances of carbon isotopes 13C and 14C combined with Bayesian mathematical modelling. In one experiment, the different age fractions were distinguished based on depth in a peat profile. In the other experiment, the age fractions were separated based on a time series of conversion from C3 vegetation to C4 vegetation. In both experiments, the temperature sensitivity of the SOM fractions was estimated by measuring the carbon isotope composition of heterotrophic soil respiration at different temperatures in laboratory. The results from these experiments suggest that the temperature sensitivity of unprotected SOM fractions increases with age, but if an environmental factor, such as bonding to soil minerals, limits decomposition of a SOM fraction, the temperature sensitivity is reduced. Our results are in agreement with the theory that suggests that in soil without environmental, physical or chemical protection, temperature sensitivity of carbon compounds is mainly determined by its chemical structure. The more complex the structure is the higher activation energy is needed and the higher its temperature sensitivity. Since SOM enriches with more complicated carbon compounds with time, this leads to increase in temperature sensitivity as SOM ages. However, our results also indicate that if the soil carbon is associated with minerals it might exhibit lower temperature sensitivities than when the carbon is "free" in the soil. Since the mineral associated carbon can have high

  3. Soil Organic Carbon Stocks in Depositional Landscapes of Bavaria

    Science.gov (United States)

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

    2016-04-01

    Erosion leads to redistribution and accumulation of soil organic matter (SOM) within agricultural landscapes. These fluvic and colluvic deposits are characterized by a highly diverse vertical structure and can contain high amounts of soil organic carbon (SOC) over the whole soil profile. Depositional landscapes are therefore not only productive sites for agricultural use but also influence carbon dynamics which is of great interest with regard on the recent climate change debate. The aim of our study is to elucidate the spatial distribution of organic carbon stocks, as well as its depth function and the role of these landscapes as a reservoir for SOM. Therefore we compare two representative depositional landscapes in Bavaria composed of different parent materials (carbonate vs. granitic). We hypothesize that the soils associated with different depositional processes (fluvial vs. colluvial) differ in SOC contents and stocks, also because of different hydromorphic regimes in fluvic versus colluvic soil profiles. Sampling sites are located in the Alpine Foreland (quaternary moraines with carbonatic parent material) and the foothills of the Bavarian Forest (Granite with Loess) with the main soil types Fluvisols, Gleysols and Luvisols. At both sites we sampled twelve soil profiles up to 150 cm depth, six in the floodplain and six along a vertical slope transect. We took undisturbed soil samples from each horizon and analyzed them for bulk density, total Carbon (OC and IC) and total Nitrogen (N) concentrations. This approach allows to calculate total OC contents and OC stocks and to investigate vertical and horizontal distribution of OC stocks. It will also reveal differences in OC stocks due to the location of the soil profile in fluvic or colluvic deposition scenarios.

  4. Enhanced top soil carbon stocks under organic farming.

    Science.gov (United States)

    Gattinger, Andreas; Muller, Adrian; Haeni, Matthias; Skinner, Colin; Fliessbach, Andreas; Buchmann, Nina; Mäder, Paul; Stolze, Matthias; Smith, Pete; Scialabba, Nadia El-Hage; Niggli, Urs

    2012-10-30

    It has been suggested that conversion to organic farming contributes to soil carbon sequestration, but until now a comprehensive quantitative assessment has been lacking. Therefore, datasets from 74 studies from pairwise comparisons of organic vs. nonorganic farming systems were subjected to metaanalysis to identify differences in soil organic carbon (SOC). We found significant differences and higher values for organically farmed soils of 0.18 ± 0.06% points (mean ± 95% confidence interval) for SOC concentrations, 3.50 ± 1.08 Mg C ha(-1) for stocks, and 0.45 ± 0.21 Mg C ha(-1) y(-1) for sequestration rates compared with nonorganic management. Metaregression did not deliver clear results on drivers, but differences in external C inputs and crop rotations seemed important. Restricting the analysis to zero net input organic systems and retaining only the datasets with highest data quality (measured soil bulk densities and external C and N inputs), the mean difference in SOC stocks between the farming systems was still significant (1.98 ± 1.50 Mg C ha(-1)), whereas the difference in sequestration rates became insignificant (0.07 ± 0.08 Mg C ha(-1) y(-1)). Analyzing zero net input systems for all data without this quality requirement revealed significant, positive differences in SOC concentrations and stocks (0.13 ± 0.09% points and 2.16 ± 1.65 Mg C ha(-1), respectively) and insignificant differences for sequestration rates (0.27 ± 0.37 Mg C ha(-1) y(-1)). The data mainly cover top soil and temperate zones, whereas only few data from tropical regions and subsoil horizons exist. Summarizing, this study shows that organic farming has the potential to accumulate soil carbon.

  5. Carbon isotope fractionation of sapropelic organic matter during early diagenesis

    Science.gov (United States)

    Spiker, E. C.; Hatcher, P.G.

    1984-01-01

    Study of an algal, sapropelic sediment from Mangrove Lake, Bermuda shows that the mass balance of carbon and stable carbon isotopes in the major organic constituents is accounted for by a relatively straightforward model of selective preservation during diagenesis. The loss of 13C-enriched carbohydrates is the principal factor controlling the intermolecular mass balance of 13C in the sapropel. Results indicate that labile components are decomposed leaving as a residual concentrate in the sediment an insoluble humic substance that may be an original biochemical component of algae and associated bacteria. An overall decrease of up to about 4??? in the ?? 13C values of the organic matter is observed as a result of early diagenesis. ?? 1984.

  6. 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.

  7. Recent Advances in Carbon Capture with Metal-Organic Frameworks.

    Science.gov (United States)

    Stylianou, Kyriakos C; Queen, Wendy L

    2015-01-01

    The escalating level of CO(2) in the atmosphere is one of the most critical environmental issues of our age. The carbon capture and storage from pilot test plants represents an option for reducing CO(2) emissions, however, the energy cost associated with post-combustion carbon capture process alone is ∼30% of the total energy generated by the power plant. Thus, the generation of carbon capture adsorbents with high uptake capacities, great separation performance and low cost is of paramount importance. Metal-organic frameworks are infinite networks of metal-containing nodes bridged by organic ligands through coordination bonds into porous extended structures and several reports have revealed that they are ideal candidates for the selective capture of CO(2). In this review we summarize recent advances related to the synthesis of porous MOFs and the latest strategies to enhance the CO(2) adsorption enthalpies and capacities at low-pressures, increase hydrolytic and mechanical stabilities, and improve the ease of regeneration. Although they show great promise for post-combustion carbon capture, there are still major challenges that must be overcome before they can be used for such a large-scale application.

  8. Temperature controls organic carbon sequestration in a subarctic lake

    Science.gov (United States)

    Rantala, Marttiina V.; Luoto, Tomi P.; Nevalainen, Liisa

    2016-10-01

    Widespread ecological reorganizations and increases in organic carbon (OC) in lakes across the Northern Hemisphere have raised concerns about the impact of the ongoing climate warming on aquatic ecosystems and carbon cycling. We employed diverse biogeochemical techniques on a high-resolution sediment record from a subarctic lake in northern Finland (70°N) to examine the direction, magnitude and mechanism of change in aquatic carbon pools prior to and under the anthropogenic warming. Coupled variation in the elemental and isotopic composition of the sediment and a proxy-based summer air temperature reconstruction tracked changes in aquatic production, depicting a decline during a cool climate interval between ~1700–1900 C.E. and a subsequent increase over the 20th century. OC accumulation rates displayed similar coeval variation with temperature, mirroring both changes in aquatic production and terrestrial carbon export. Increase in sediment organic content over the 20th century together with high inferred aquatic UV exposure imply that the 20th century increase in OC accumulation is primarily connected to elevated lake production rather than terrestrial inputs. The changes in the supply of autochthonous energy sources were further reflected higher up the benthic food web, as evidenced by biotic stable isotopic fingerprints.

  9. Latitudinal gradients in degradation of marine dissolved organic carbon

    DEFF Research Database (Denmark)

    Arnosti, Carol; Steen, Andrew; Ziervogel, Kai;

    2011-01-01

    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 CO2 reservoir...... 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......, such a change could profoundly affect the global carbon cycle....

  10. Temperature sensitivity of organic carbon mineralization in contrasting lake sediments

    OpenAIRE

    Gudasz, Cristian; Sobek, Sebastian; Bastviken, David; Koehler, Birgit; Tranvik, Lars J.

    2015-01-01

    Temperature alone explains a great amount of variation in sediment organic carbon (OC) mineralization. Studies on decomposition of soil OC suggest that (1) temperature sensitivity differs between the fast and slowly decomposition OC and (2) over time, decreasing soil respiration is coupled with increase in temperature sensitivity. In lakes, autochthonous and allochthonous OC sources are generally regarded as fast and slowly decomposing OC, respectively. Lake sediments with different contribut...

  11. Riparian zone hydrology and soil water total organic carbon (TOC)

    OpenAIRE

    T. Grabs; K. Bishop; Laudon, H.; Lyon, S. W.; Seibert, J.

    2012-01-01

    Groundwater flowing from hillslopes through riparian (near-stream) soils often undergoes chemical transformations that can substantially influence stream water chemistry. We used landscape analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow–concentration integratio...

  12. Dissolved organic carbon fluxes by seagrass meadows and macroalgal beds

    OpenAIRE

    Barrón, Cristina; Apostolaki, Eugenia T.; Duarte, Carlos M.

    2014-01-01

    Estimates of dissolved organic carbon (DOC) release by marine macrophyte communities (seagrass meadows and macroalgal beds) based on in situ benthic chambers from published and unpublished are compiled in this study. The effect of temperature and light availability on DOC release by macrophyte communities was examined. Almost 85% of the seagrass communities and all of macroalgal communities examined acted as net sources of DOC. Net DOC fluxes in seagrass communities increase positively with w...

  13. Aged Riverine Particulate Organic Carbon in Four UK Catchments

    Science.gov (United States)

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

    2016-04-01

    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, PO14C 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 PO14C value for the 7 sites of 91.2 pMC corresponded to an average age of 680 14C 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 PO14C 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-14C topsoil organic matter by mineralisation during riverine transport. The significantly lower average PO14C 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 PO14C in rivers draining catchments with low erosion rates.

  14. 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.

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

    International Nuclear Information System (INIS)

    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

  16. 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. PMID:25385632

  17. Direct measurement of riverine particulate organic carbon age structure

    Science.gov (United States)

    Rosenheim, Brad E.; Galy, Valier

    2012-10-01

    Carbon cycling studies focusing on transport and transformation of terrigenous carbon sources toward marine sedimentary sinks necessitate separation of particulate organic carbon (OC) derived from many different sources and integrated by river systems. Much progress has been made on isolating and characterizing young biologically-formed OC that is still chemically intact, however quantification and characterization of old, refractory rock-bound OC has remained troublesome. Quantification of both endmembers of riverine OC is important to constrain exchanges linking biologic and geologic carbon cycles and regulating atmospheric CO2 and O2. Here, we constrain petrogenic OC proportions in suspended sediment from the headwaters of the Ganges River in Nepal through direct measurement using ramped pyrolysis radiocarbon analysis. The unique results apportion the biospheric and petrogenic fractions of bulk particulate OC and characterize biospheric OC residence time. Compared to the same treatment of POC from the lower Mississippi-Atchafalaya River system, contrast in age spectra of the Ganges tributary samples illustrates the difference between small mountainous river systems and large integrative ones in terms of the global carbon cycle.

  18. Comparation of Rabbit Skin Tanned by Different Organic Phosphate%有机磷盐鞣制兔皮性能比较

    Institute of Scientific and Technical Information of China (English)

    李瑶; 周裕婷; 刘强; 张宗才

    2011-01-01

    The organic phosphate is a kind of nontoxic phosphor compound without environmental pollution. It has been regarded as an ideal chrome-free tanning agent due to its good protein crosslinking characteristics. On the basis of studying on organic phosphate tanning of goatskin leather, application of organic phosphate tanning technology on rabbit skin and the tanning performance of different organic phosphate were studied in this paper.%有机磷盐是一种低毒、无污染的具有羟甲基结构的含磷化合物.由于其优良的蛋白质交联性能,被认为是一种较理想的无铬鞣剂,而成为当前皮革鞣制研究的重点.本文在原有有机磷盐鞣制山羊皮革研究的基础上,进一步研究有机磷盐鞣制兔皮的工艺技术,并比较了多种有机磷盐的鞣制性能.

  19. Carbon uptake in low dissolved inorganic carbon environments: the effect of limited carbon availability on photosynthetic organisms in thermal waters

    Science.gov (United States)

    Myers, K. D.; Omelon, C. R.; Bennett, P.

    2010-12-01

    Photosynthesis is the primary carbon fixation process in thermal waters below 70°C, but some hydrothermal waters have extremely low dissolved inorganic carbon (DIC), potentially limiting the growth of inorganic carbon fixing organisms such as algae and cyanobacteria. To address the issue of how carbon is assimilated by phototrophs in these environments, we conducted experiments to compare inorganic carbon uptake mechanisms by two phylogenetically distinct organisms collected from geographically distinct carbon limited systems: the neutral pH geothermal waters of El Tatio, Chile, and the acidic geothermal waters of Tantalus Creek in Norris Geyser Basin, Yellowstone National Park. Discharge waters at El Tatio have low total DIC concentrations (2 to 6 ppm) found mainly as HCO3-; this is in contrast to even lower measured DIC values in Tantalus Creek (as low as 0.13 ppm) that, due to a measured pH of 2.5, exists primarily as CO2. Cyanobacteria and algae are innately physiologically plastic, and we are looking to explore the possibility that carbon limitation in these environments is extreme enough to challenge that plasticity and lead to a suite of carbon uptake adaptations. We hypothesize that these microorganisms utilize adaptive modes of Ci uptake that allow them to survive under these limiting conditions. Cyanobacteria (primarily Synechococcus spp.) isolated from El Tatio can utilize either passive CO2 uptake or active HCO3- uptake mechanisms, in contrast to the eukaryotic alga Cyanidium spp. from Tantalus Creek, which is restricted to an energy-dependent CO2 uptake mechanism. To test this hypothesis, we conducted pH drift experiments (Omelon et al., 2008) to examine changes in pH and [DIC] under a range of pH and [DIC] culture conditions. This work provides baseline information upon which we will begin to investigate the effects of low [DIC] on the growth of phototrophs collected from these and other less carbon limited systems.

  20. Understanding drivers of the export of dissolved organic carbon from a German headwater catchment using Generalised Additive Models

    Science.gov (United States)

    Selle, Benny; Musolff, Andreas; Tittel, Jörg

    2016-04-01

    In the literature, several causes of recently increasing concentrations of dissolved organic carbon (DOC) in headwaters across eastern North America and northern and central Europe have been debated. One likely driver of the widespread increase of DOC concentrations since the early 1990s are decreasing depositions of acid rain resulting in an increased solubility of organic carbon compounds including humic acids. Here, we tested the hypothesis if the reduced availability of nitrate stimulated the microbial reduction of ferric iron soil minerals and the mobilisation of DOC. Forested catchments are relatively unaffected by agricultural and urban nitrate inputs. In these catchments, decreasing depositions often resulted in a reduced availability of nitrate, which are preferred electron acceptors in microbial decomposition processes. As ferric iron minerals act as efficient sorbents of organic compounds in soils its reduction may cause a release of humic substances and hence an export of DOC. To test this hypothesis, time series of DOC, dissolved iron and nitrate from a forested headwater catchment in Germany were examined using Generalised Additive Models. We found that rising DOC concentrations most likely resulted from a reductive dissolution of iron(III) minerals in soils and the associated mobilisation of adsorbed organic carbon. Phosphate, which can trigger undesired algal growth and is also known to be adsorbed by particulate iron(III), was released as well.

  1. Impacts of crop rotations on soil organic carbon sequestration

    Science.gov (United States)

    Gobin, Anne; Vos, Johan; Joris, Ingeborg; Van De Vreken, Philippe

    2013-04-01

    Agricultural land use and crop rotations can greatly affect the amount of carbon sequestered in the soil. We developed a framework for modelling the impacts of crop rotations on soil carbon sequestration at the field scale with test case Flanders. A crop rotation geo-database was constructed covering 10 years of crop rotation in Flanders using the IACS parcel registration (Integrated Administration and Control System) to elicit the most common crop rotation on major soil types in Flanders. In order to simulate the impact of crop cover on carbon sequestration, the Roth-C model was adapted to Flanders' environment and coupled to common crop rotations extracted from the IACS geodatabases and statistical databases on crop yield. Crop allometric models were used to calculate crop residues from common crops in Flanders and subsequently derive stable organic matter fluxes to the soil (REGSOM). The REGSOM model was coupled to Roth-C model was run for 30 years and for all combinations of seven main arable crops, two common catch crops and two common dosages of organic manure. The common crops are winter wheat, winter barley, sugar beet, potato, grain maize, silage maize and winter rapeseed; the catch crops are yellow mustard and Italian ryegrass; the manure dosages are 35 ton/ha cattle slurry and 22 ton/ha pig slurry. Four common soils were simulated: sand, loam, sandy loam and clay. In total more than 2.4 million simulations were made with monthly output of carbon content for 30 years. Results demonstrate that crop cover dynamics influence carbon sequestration for a very large percentage. For the same rotations carbon sequestration is highest on clay soils and lowest on sandy soils. Crop residues of grain maize and winter wheat followed by catch crops contribute largely to the total carbon sequestered. This implies that agricultural policies that impact on agricultural land management influence soil carbon sequestration for a large percentage. The framework is therefore

  2. Evaluation of Powdered Activated Carbon Efficiency in Removal of Dissolved Organic Carbon inWater Treatment

    Directory of Open Access Journals (Sweden)

    G.R Bonyadi nejad

    2010-07-01

    Full Text Available "n "nBackgrounds and Objectives: Powdered Activated$ carbon is known as a suitable absorbent for organic materials. The aim of this research is evaluation of Powdered Activated-Carbon (PAC efficiency in removal of Dissolved Organic Carbon (DOC in water treatment in Isfahan."nMaterials and Methods : The increase of PAC for DOC reduction has done in three paths in the Isfahan water treatment plant (WTP. These paths including: 1 Intake up to entrance of WTP 2 Intake to exit ofWTP 3 Between entrance and exit of waterworks. The paths were simulated by the Jar test system. Then DOC and UV254 absorption were analyzed and SUVA parameter for samples and activated-carbon adsorption isotherm was calculated."nResults: The injected PAC doses of 20,40,60,80 and 100 mg/l caused decreasing in DOC and UV254 absorption in every sample in all paths. The average of this decrease, from intake to WTP.s exit (second path was the greatest 69.8± 3.9%and the commonWTP process had capability of removing 35% of DOC. The first path also showed that PAC can reduce 33± 2% DOC of raw water by itself. Activated-carbon absorption results were adhered from Freundlich adsorption isotherm."nConclusion: In the third path therewas lessDOCremoval efficiency than exceptedwhen Activated- Carbon injected in rapid mixed basin with coagulant. Powdered activated carbon porosity reduction due to effect of coagulant can be the reason for this issue.Also according to different paths, the point of intake is more suitable for powdered activated carbon addition.

  3. Direct Imaging of Nanoscale Dissolution of Dicalcium Phosphate Dihydrate by an Organic Ligand: Concentration Matters

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Lihong [Huazhong Agricultural University, China; Zhang, Wenjun [Huazhong Agricultural University, China; Lu, Jianwei [Huazhong Agricultural University, China; Stack, Andrew G [ORNL; Wang, Lijun [Huazhong Agricultural University, China

    2013-01-01

    Unraveling the kinetics and mechanisms of sparingly soluble calcium orthophosphate (Ca!P) dissolution in the presence of organic acids at microscopic levels is important for an improved understanding in determining the effectiveness of organic acids present in most rhizosphere environments. Herein, we use in situ atomic force microscopy (AFM) coupled with a fluid reaction cell to image dissolution on the (010) face of brushite, CaHPO4 2H2O, in citrate- bearing solutions over a broad concentration range. We directly measure the dependence of molecular step retreat rate on citrate concentration at various pH values and ionic strengths, relevant to soil solution conditions. We find that low concentrations of citrate(10!100 M)inducedareductioninstepretreatratesalongboththe[10 0]Ccand[101] Ccdirections.However,at higher concentrations (exceeding 0.1 mM), this inhibitory effect was reversed with step retreat speeds increasing rapidly. These results demonstrate that the concentration-dependent modulation of nanoscale Ca!P phase dissolution by citrate may be applied to analyze the controversial role of organic acids in enhancing Ca!P mineral dissolution in a more complex rhizosphere environment. These in situ observations may contribute to resolving the previously unrecognized interactions of root exudates (low molecular weight organic acids) and sparingly soluble Ca!P minerals.

  4. Primary and secondary organic carbon downwind of Mexico City

    Directory of Open Access Journals (Sweden)

    X.-Y. Yu

    2009-01-01

    Full Text Available In order to study particulate matter transport and transformation in the Megacity environment, fine particulate carbons were measured simultaneously at two supersites, suburban T1 and rural T2, downwind of Mexico City during the MILAGRO field campaign in March 2006. Organic carbon (OC, element carbon (EC, and total carbon (TC=OC+EC were determined in near real-time using a Sunset semi-continuous OC/EC field analyzer. The semi-empirical EC tracer method was used to derive primary organic carbon (POC and secondary organic carbon (SOC. Diurnal variations of primary and secondary carbons were observed at T1 and T2, which resulted from boundary layer inversion and impacted by local traffic patterns. The majority of organic carbon particles at T1 and T2 were secondary. The SOC% (SOC%=SOC/TC×100% at T1 ranged from 1.2–100% with an average of 80.7±14.4%. The SOC% at T2 ranged from 12.8–100% with an average of 80.1±14.0%. The average EC to PM2.5 percentage (ECPM%=EC/PM2.5×100% and OCPM% were 6.0% and 20.0% over the whole sampling time at T1. The POC to PM percentage (POCPM% and SOCPM% were 3.7% and 16.3%, respectively at the same site. The maximum ECPM% was 21.2%, and the maximum OCPM% was 57.2% at T1. The maximum POCPM% was 12.9%, and the maximum SOCPM% was 49.7% at the suburban site. Comparison of SOC and POC at T1 and T2 showed similar characteristics under favorable meteorological conditions, which indicated that transport between the two supersites took place. Strong correlations between EC and carbon monoxide (CO and odd nitrogen species (NO and NOx were observed at T1. This indicated that EC had nearby sources, such as local traffic emissions. The EC/CO ratio derived by linear regression analysis, when parameters in μg C/m3 and μg/m3, respectively, was 0.0045 at T1. Correlations were also seen

  5. Primary and secondary organic carbon downwind of Mexico City

    Directory of Open Access Journals (Sweden)

    X.-Y. Yu

    2009-09-01

    Full Text Available In order to study particulate matter transport and transformation in the Megacity environment, fine particulate carbon was measured simultaneously at two supersites, suburban T1 and rural T2, downwind of Mexico City during the MILAGRO field campaign in March 2006. Organic carbon (OC, element carbon (EC, and total carbon (TC=OC+EC were determined in near real-time using a Sunset semi-continuous OCEC field analyzer. The semi-empirical EC tracer method was used to derive primary organic carbon (POC and secondary organic carbon (SOC. Diurnal variations of primary and secondary carbon were observed at T1 and T2, which resulted from boundary layer inversion and impacted by local traffic patterns. The majority of organic carbon particles at T1 and T2 were secondary. The SOCTC% (SOC%=SOC/TC×100% at T1 ranged from 0.5–93.8% with an average of 63.5±17.2%. The SOCTC% at T2 ranged from 9.3–98.1% with an average of 67.4±12.4%. The average EC to PM2.5 percentage (ECPM%=EC/PM2.5×100% and OCPM% were 6.0% and 20.0% over the whole sampling time at T1. The POC to PM percentage (POCPM% and SOCPM% were 3.7% and 16.3%, respectively at the same site. The maximum ECPM% was 21.2%, and the maximum OCPM% was 57.2% at T1. The maximum POCPM% was 12.9%, and the maximum SOCPM% was 49.7% at T1. Comparison of SOC and POC at T1 and T2 showed similar characteristics under favorable meteorological conditions, which indicated that transport from T1 towards T2 took place. Strong correlations between EC and carbon monoxide (CO and odd nitrogen species (NO and NOx were observed at T1. This indicated that EC had nearby sources, such as local traffic emissions. The EC/CO ratio derived by linear regression analysis, with units of μg C/m3 and μg/m3, respectively, was 0.004 at T1. Correlations were also seen between

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

    Energy Technology Data Exchange (ETDEWEB)

    Yusufoglu, Yusuf

    2009-08-15

    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. 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.

  8. Organic carbon redistribution due to erosion at various spatial scales

    Science.gov (United States)

    Jakab, Gergely; Szabó, Judit; Szalai, Zoltán; Mészáros, Erzsébet; Szabó, Boglárka; Centeri, Csaba

    2016-04-01

    Soil organic carbon (SOC) has a crucial role both in terms of crop production and climate change mitigation. Soil could be an effective sink of atmospheric carbon since in agricultural areas the carbon content of the soil is much lower than its capacity. The main obstacle against carbon charge of the soils is cultivation and erosion. Soil detachment, delivery and deposition are rather scale dependent processes that is why it is difficult to compare or extrapolate results among scales. Present case study aims to compare the SOC content and soil organic matter (SOM) compound of the detached soil particles on the ridge to those that are deposited at the bottom of the catena in order to clarify the role of delivery in soil erosion. Initial soil erosion was modelled using a laboratory rainfall simulator at the point scale. Deposition was surveyed and analysed by 3D sampling from drillings on the sedimentary parts at the field scale. At the detachment phase carbon enrichment (50-100%) and C/N ratio increase were found in each aggregate size class of the detached soil particles. Variations in SOM compounds suggested that a very intensive SOM exchange took place during initial erosion processes and delivery. In addition to the selective erosion selective SOC deposition were also found at the field scale. Two topographical hotspots were identified as the place of SOC surplus deposition. In these patches SOM compounds were deposited separately due to different geomorphologic positions. The lower patch next to the end of an ephemeral gully was dominated by less polymerized more aromatic SOM, while the upper one was ruled by high molecular weighted aliphatic SOM. Difference in SOM compound was manifested also in different sediment morphology. The topographically higher deposition patch were covered by aggregates while the lower one was found to be sealed by individual soil particles. Present study was supported by the National Hungarian Research Found K100180, G. Jakab was

  9. Dissolved organic carbon (DOC in Arctic ground ice

    Directory of Open Access Journals (Sweden)

    M. Fritz

    2015-01-01

    Full Text Available Thermal permafrost degradation and coastal erosion in the Arctic remobilize substantial amounts of organic carbon (OC and nutrients which have been accumulated in late Pleistocene and Holocene unconsolidated deposits. Their vulnerability to thaw subsidence, collapsing coastlines and irreversible landscape change is largely due to the presence of large amounts of massive ground ice such as ice wedges. However, ground ice has not, until now, been considered to be a source of dissolved organic carbon (DOC, dissolved inorganic carbon (DIC and other elements, which are important for ecosystems and carbon cycling. Here we show, using geochemical data from a large number of different ice bodies throughout the Arctic, that ice wedges have the greatest potential for DOC storage with a maximum of 28.6 mg L−1 (mean: 9.6 mg L−1. Variation in DOC concentration is positively correlated with and explained by the concentrations and relative amounts of typically terrestrial cations such as Mg2+ and K+. DOC sequestration into ground ice was more effective during the late Pleistocene than during the Holocene, which can be explained by rapid sediment and OC accumulation, the prevalence of more easily degradable vegetation and immediate incorporation into permafrost. We assume that pristine snowmelt is able to leach considerable amounts of well-preserved and highly bioavailable DOC as well as other elements from surface sediments, which are rapidly stored in ground ice, especially in ice wedges, even before further degradation. In the Yedoma region ice wedges represent a significant DOC (45.2 Tg and DIC (33.6 Tg pool in permafrost areas and a fresh-water reservoir of 4172 km3. This study underlines the need to discriminate between particulate OC and DOC to assess the availability and vulnerability of the permafrost carbon pool for ecosystems and climate feedback upon mobilization.

  10. Validation and Scenario Analysis of a Soil Organic Carbon Model

    Institute of Scientific and Technical Information of China (English)

    HUANG Yao; LIU Shi-liang; SHEN Qi-rong; ZONG Liang-gang; JIANG Ding-an; HUANG Hong-guang

    2002-01-01

    A model developed by the authors was validated against independent data sets. The data sets were obtained from field experiments of crop residue decomposition and a 7-year soil improvement in Yixing City, Jiangsu Province. Model validation indicated that soil organic carbon dynamics can be simulated from the weather variables of temperature, sunlight and precipitation, soil clay content and bulk density, grain yield of previous crops, qualities and quantities of the added organic matter. Model simulation in general agreed with the measurements. The comparison between computed and measured resulted in correlation coefficient γ2 values of 0.9291 * * * (n = 48) and 0. 6431 * * (n = 65) for the two experiments, respectively. Model prediction under three scenarios of no additional organic matter input, with an annual incorporation of rice and wheat straw at rates of 6.75t/ha and 9.0t/ha suggested that the soil organic carbon in Wanshi Township of Yixing City would be from an initial value of 7.85g/kg in 1983 to 6.30g/kg, 11.42g/kg and 13g/kg in 2014, respectively. Consequently, total nitrogen content of the soil was predicted to be respectively 0.49g/kg,0.89g/kg and 1.01g/kg under the three scenarios.

  11. 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, ANOVA and Tukey statistical analysis were carried out for all data. The SOC was higher in ICLS than in CCS at both depths (20.8 vs 17.7 g kg-1 for 0-5 cm and 16.1 vs 12.7 g kg-1 at 0-20 cm, respectively, P<0.05). MOC was similar at both depths, and POC was higher in CCS than in ICLS at 0-5 cm, while at 0-20 cm this trend was opposite. This is probably due to the presence of deep roots under pastures in ICLS. Delta

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

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2010-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Y. Miyazaki

    2011-04-01

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

  14. 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

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

    DEFF Research Database (Denmark)

    Guidi, Claudia

    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 ...... grasslands, which can be explained by lower accumulation of binding agents of microbial origin. This can have implications for the accumulation of atmospheric CO2 in soil and for the susceptibility of SOC to external disturbances such as management and environmental changes.......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...... involved into long-term stability are largely unknown. The aim of this PhD thesis was to explore changes in: (i) SOC stocks; (ii) physical SOC fractions; and (iii) labile soil carbon components following forest expansion on mountain grasslands. A land-use gradient located in the Southern Alps (Italy...

  16. 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...

  17. Effect of land use change on soil organic carbon

    Directory of Open Access Journals (Sweden)

    Barančíková Gabriela

    2016-04-01

    Full Text Available The direction of changes and conversion of soil organic carbon (SOC is in most current ecosystems influenced by human activity. Soil Science and Conservation Research Institute is responsible for monitoring the agricultural soils in a five-year cycle. One part of the soil monitoring involves the determination of the soil organic carbon (SOC storage. Further, we followed the conversion of arable land on grassland during more than 20 years of monitoring period at some locations where changes in land use occurred. Ten places on basic network and 2 places on key monitoring localities in which arable land have been converted into grassland were identified. About 50 percent of studied soils converted into permanent grassland were Cambisols. The other converted soil types were Luvic Stagnosol, Stagnic Regosol, Mollic Fluvisol, and Stagnic Luvisol. The results showed that after the third monitoring cycle (2002, increase of SOC was observed in all the localities, with the change in land use. Statistical parameter (t-test confirmed significant differences between the set of average SOC values before and after the land use conversion. The chemical structure of humic acids (HA isolated from arable soil and permanent grassland indicated increasing of aliphatic carbon content in grassland HA. More aromatic and stabile were HA isolated from arable soils.

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

    Science.gov (United States)

    Bliss, Norman B.; Waltman, Sharon W.; 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.

  19. Highly fluorescent xerogels with entrapped carbon dots for organic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, A., E-mail: quaranta@ing.unitn.it [University of Trento, Department of Industrial Engineering, via Mesiano, 77, 38123 Trento (Italy); Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); Carturan, S. [Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); University of Padova, Department of Physics and Astronomy “Galileo Galilei”, Via Marzolo, 8, 35131 Padova (Italy); Campagnaro, A.; Dalla Palma, M. [University of Trento, Department of Industrial Engineering, via Mesiano, 77, 38123 Trento (Italy); Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); Giarola, M.; Daldosso, N. [University of Verona, Department of Informatics, Strada le Grazie,15, 37134 Verona (Italy); Maggioni, G. [Laboratori Nazionali di Legnaro, INFN, Viale dell' Università, 2, 35020 Legnaro (PD) (Italy); University of Padova, Department of Physics and Astronomy “Galileo Galilei”, Via Marzolo, 8, 35131 Padova (Italy); Mariotto, G. [University of Verona, Department of Informatics, Strada le Grazie,15, 37134 Verona (Italy)

    2014-02-28

    Organically modified silicate thin film and bulk samples were prepared using [3-(2-aminoethylamino)propyl]trimethoxysilane (AEAP-TMOS) as precursor with the addition of different amounts of AEAP-TMOS functionalized C-dots, prepared by reaction of AEAP-TMOS and citric acid at high temperature. The synthesis of surface functionalized C-dots was followed by Fourier Transform Infrared (FTIR) spectroscopy, and the C-dots optical properties were characterized by optical absorption and UV–vis fluorescence. Thin xerogel films and bulk samples were studied by FTIR, Raman and fluorescence spectroscopy. Intense blue-green emission was observed by UV excitation of functionalized C-dots. Carbon quantum dot (CQD) luminescence was preserved also in the xerogel matrices, and the energy transfer from the matrix to CQDs, which is a key characteristic for scintillation detectors, was investigated in the two systems. - Highlights: • Functionalized carbon dots were synthesized. • Carbon dots were dispersed in hybrid xerogel bulk and thin film. • Carbon dots exhibit a strong tunable blue luminescence. • Xerogels were characterized by FT-IR, Raman and fluorescence spectroscopies. • Energy transfer processes were evidenced between C-dots and xerogel matrix.

  20. 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.

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

    OpenAIRE

    Lizhen Xing; Li Ren; Bo Tang,; Guangxue Wu; Yuntao Guan

    2013-01-01

    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 app...

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

    Science.gov (United States)

    Shoja, Yalda; Rafati, Amir Abbas; 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--NH2 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.

  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. Phosphate sensing

    OpenAIRE

    Bergwitz, Clemens; Jüppner, Harald

    2011-01-01

    Human phosphate homeostasis is regulated at the level of intestinal absorption of phosphate from the diet, release of phosphate through bone resorption, and renal phosphate excretion and involves the actions of parathyroid hormone (PTH), 1,25-dihydroxy-vitamin D (1,25-(OH)2-D), and fibroblast growth factor 23 (FGF23) to maintain circulating phosphate levels within a narrow normal range, which is essential for numerous cellular functions, for the growth of tissues and for bone mineralization. ...

  6. A molecular organic carbon isotope record of miocene climate changes.

    Science.gov (United States)

    Schoell, M; Schouten, S; Damsté, J S; de Leeuw, J W; Summons, R E

    1994-02-25

    The difference in carbon-13 ((13)C) contents of hopane and sterane biomarkers in the Monterey formation (Naples Beach, California) parallels the Miocene inorganic record of the change in (18)O (delta(18)O), reflecting the Miocene evolution from a well-mixed to a highly stratified photic zone (upper 100 meters) in the Pacific. Steranes (delta(13)C = 25.4 +/- 0.7 per mil versus the Pee Dee belemnite standard) from shallow photic-zone organisms do not change isotopically throughout the Miocene. In contrast, sulfur-bound C(35) hopanes (likely derived from bacterial plankton living at the base of the photic zone) have systematically decreasing (13)C concentrations in Middle and Late Miocene samples (delta(13)C = -29.5 to -31.5 per mil), consistent with the Middle Miocene formation of a carbon dioxide-rich cold water mass at the base of the photic zone. PMID:17831625

  7. Spatial Characteristics of Soil Organic Carbon Storage in China's Croplands

    Institute of Scientific and Technical Information of China (English)

    WANG Shao-Qiang; YU Gui-Rui; ZHAO Qian-Jun; NIU Dong; CHEN Qing-Mei; WU Zhi-Feng

    2005-01-01

    The soil organic carbon (SOC) pool is the largest component of terrestrial carbon pools. With the construction of a geographically referenced database taken from the second national general soil survey materials and based on 1 546typical cropland soil profiles, the paddy field and dryland SOC storage among six regions of China were systematically quantified to characterize the spatial pattern of cropland SOC storage in China and to examine the relationship between mean annual temperature, precipitation, soil texture features and SOC content. In all regions, paddy soils had higher SOC storage than dryland soils, and cropland SOC content was the highest in Southwest China. Climate controlled the spatial distribution of SOC in both paddy and dryland soils, with SOC storage increasing with increasing precipitation and decreasing with increasing temperature.

  8. Sulfur and carbon cycling in organic-rich marine sediments

    Science.gov (United States)

    Martens, C. S.

    1985-01-01

    Nearshore, continental shelf, and slope sediments are important sites of microbially mediated carbon and sulfur cycling. Marine geochemists investigated the rates and mechanisms of cycling processes in these environments by chemical distribution studies, in situ rate measurements, and steady state kinetic modeling. Pore water chemical distributions, sulfate reduction rates, and sediment water chemical fluxes were used to describe cycling on a ten year time scale in a small, rapidly depositing coastal basin, Cape Lookout Bight, and at general sites on the upper continental slope off North Carolina, U.S.A. In combination with 210 Pb sediment accumulation rates, these data were used to establish quantitative carbon and sulfur budgets as well as the relative importance of sulfate reduction and methanogeneis as the last steps in the degradation of organic matter.

  9. Environmental analyse of soil organic carbon stock changes in Slovakia

    Science.gov (United States)

    Koco, Š.; Barančíková, G.; Skalský, R.; Tarasovičová, Z.; Gutteková, M.; Halas, J.; Makovníková, J.; Novákova, M.

    2012-04-01

    The content and quality of soil organic matter is one of the basic soil parameters on which soil production functioning depends as well as it is active in non production soil functions like an ecological one especially. Morphologic segmentation of Slovakia has significant influence of structure in using agricultural soil in specific areas of our territory. Also social changes of early 90´s of 20´th century made their impact on change of using of agricultural soil (transformation from large farms to smaller ones, decreasing the number of livestock). This research is studying changes of development of soil organic carbon stock (SOC) in agricultural soil of Slovakia as results of climatic as well as social and political changes which influenced agricultury since last 40 years. The main goal of this research is an analysis of soil organic carbon stock since 1970 until now at specific agroclimatic regions of Slovakia and statistic analysis of relation between modelled data of SOC stock and soil quality index value. Changes of SOC stock were evaluated on the basis SOC content modeling using RothC-26.3 model. From modeling of SOC stock results the outcome is that in that time the soil organic carbon stock was growing until middle 90´s years of 20´th century with the highest value in 1994. Since that year until new millennium SOC stock is slightly decreasing. After 2000 has slightly increased SOC stock so far. According to soil management SOC stock development on arable land is similar to overall evolution. In case of grasslands after slight growth of SOC stock since 1990 the stock is in decline. This development is result of transformational changes after 1989 which were specific at decreasing amount of organic carbon input from organic manure at grassland areas especially. At warmer agroclimatic regions where mollic fluvisols and chernozems are present and where are soils with good quality and steady soil organic matter (SOM) the amount of SOC in monitored time is

  10. 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

  11. Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.

    OpenAIRE

    Tsuji, Yasushi; Fujihara, Tetsuaki

    2012-01-01

    Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role.

  12. Organic carbon decomposition rates controlled by water retention time across inland waters

    Science.gov (United States)

    Catalán, Núria; Marcé, Rafael; Kothawala, Dolly N.; Tranvik, Lars. J.

    2016-07-01

    The loss of organic carbon during passage through the continuum of inland waters from soils to the sea is a critical component of the global carbon cycle. Yet, the amount of organic carbon mineralized and released to the atmosphere during its transport remains an open question, hampered by the absence of a common predictor of organic carbon decay rates. Here we analyse a compilation of existing field and laboratory measurements of organic carbon decay rates and water residence times across a wide range of aquatic ecosystems and climates. We find a negative relationship between the rate of organic carbon decay and water retention time across systems, entailing a decrease in organic carbon reactivity along the continuum of inland waters. We find that the half-life of organic carbon is short in inland waters (2.5 +/- 4.7 yr) compared to terrestrial soils and marine ecosystems, highlighting that freshwaters are hotspots of organic carbon degradation. Finally, we evaluate the response of organic carbon decay rates to projected changes in runoff. We calculate that regions projected to become drier or wetter as the global climate warms will experience changes in organic carbon decay rates of up to about 10%, which illustrates the influence of hydrological variability on the inland waters carbon cycle.

  13. Burial of organic carbon and carbonate on inner shelf of the northern South China Sea during the postglacial period

    Institute of Scientific and Technical Information of China (English)

    Shouye YANG; Wyss W.-S. YIM; Min TANG; Guangqing HUANG

    2008-01-01

    Two vibrocores from the inner shelf off Hong Kong are investigated to compare the contents of organic and inorganic carbon in postglacial sediments. The com-positions of organic elements and carbonate are highly variable in the core sediments, but overall drop within the compositional ranges of modern seabed sediments in the Zhujiang estuarine and its shelf area. The Holocene sediments in the inner shelf have never been subject to subaerial exposure and the organic matter and carbonate can be preserved well. The burial of carbon in river-domi-nated shelf environments is highly dependent on the river flux with time. Nevertheless, it is difficult to establish a simple relationship between carbon burial in sediments in relation to climatic changes of basin-wide scale due to complex controls of production, transport and deposition of organic matter and carbonate. Our study suggests that the organic carbon to nitrogen ratio can not reliably identify the sources of depositional organic matters because of selective decomposition of organic matter com-ponents during humification and sedimentation. Caution is therefore needed in using organic elemental composi-tions as indicators of organic matter sources and paleoen-vironmental changes in the East Asian continental shelves where intense river-sea interaction and variable carbon flux in geologic record occur.

  14. Aggregate distribution and associated organic carbon influenced by cover crops

    Science.gov (United States)

    Barquero, Irene; García-González, Irene; Benito, Marta; Gabriel, Jose Luis; Quemada, Miguel; Hontoria, Chiquinquirá

    2013-04-01

    Replacing fallow with cover crops during the non-cropping period seems to be a good alternative to diminish soil degradation by enhancing soil aggregation and increasing organic carbon. The aim of this study was to analyze the effect of replacing fallow by different winter cover crops (CC) on the aggregate distribution and C associated of an Haplic Calcisol. The study area was located in Central Spain, under semi-arid Mediterranean climate. A 4-year field trial was conducted using Barley (Hordeum vulgare L.) and Vetch (Vicia sativa L.) as CC during the intercropping period of maize (Zea mays L.) under irrigation. All treatments were equally irrigated and fertilized. Maize was directly sown over CC residues previously killed in early spring. Composite samples were collected at 0-5 and 5-20 cm depths in each treatment on autumn of 2010. Soil samples were separated by wet sieving into four aggregate-size classes: large macroaggregates ( >2000 µm); small macroaggregates (250-2000 µm); microaggregates (53-250 µm); and Organic carbon associated to each aggregate-size class was measured by Walkley-Black Method. Our preliminary results showed that the aggregate-size distribution was dominated by microaggregates (48-53%) and the cover crops increased aggregate size resulting in a higher MWD (0.28 mm) in comparison with fallow (0.20 mm) in the 0-5 cm layer. Barley showed a higher MWD than fallow also in 5-20 cm layer. Organic carbon concentrations in aggregate-size classes at top layer followed the order: large macroaggregates > small macroaggregates > microaggregates > silt + clay size. Treatments did not influence C concentration in aggregate-size classes. In conclusion, cover crops improved soil structure increasing the proportion of macroaggregates and MWD being Barley more effective than Vetch at subsurface layer.

  15. 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.

  16. Organic carbon concentrations and stocks in Romanian mineral forest soils

    Directory of Open Access Journals (Sweden)

    Lucian C. Dincă

    2012-12-01

    Full Text Available Estimating soils organic carbon stock and its change in time is an actual concern for scientists and climate change policy makers. The present article firstly focus on determination of C stocks in Romania on forest soil types, as well as development of the spatial distribution mapping using a Geographic Information System (GIS and also the secondly on the quantification of uncertainty associated with currently available data on C concentration on forest soils geometrical layers. Determination of C stock was done based on forest management plans database created over 2000-2006. Unlike original database, the data for this study was harmonized on following depths: 0-10 cm, 10-20 cm, 20-40 cm, and > 40 cm. Then, the obtained values were grouped by soil types, resulting average values for the main forest soils from Romania. A soil area weighted average value of 137 t/ha is calculated for Romania, in the range of estimations for other European geographic and climatic areas. The soils that have the largest amount of organic carbon are andosols, vertisols, entic and haplic podzols, whereas the ones that have the smallest values of organic carbon are solonetz and solonchaks. Although current assessment relies on very large number of samples from the forest management planning database, the variability of C concentration remains very large, ~40-50% for coefficient the variation and ~100% of the average, when defining the range of 95% of entire soil population, rather showing the variability than uncertainty of the average estimated. Best fit for C concentration on geometric layers in any forest soil is asymmetric, associated with log-normal distributions.

  17. 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. 

  18. Stable carbon isotope ratios of ambient aromatic volatile organic compounds

    Science.gov (United States)

    Kornilova, Anna; Huang, Lin; Saccon, Marina; Rudolph, Jochen

    2016-09-01

    Measurements of mixing ratios and stable carbon isotope ratios of aromatic volatile organic compounds (VOC) in the atmosphere were made in Toronto (Canada) in 2009 and 2010. Consistent with the kinetic isotope effect for reactions of aromatic VOC with the OH radical the observed stable carbon isotope ratios are on average significantly heavier than the isotope ratios of their emissions. The change of carbon isotope ratio between emission and observation is used to determine the extent of photochemical processing (photochemical age, ∫ [OH]dt) of the different VOC. It is found that ∫ [OH]dt of different VOC depends strongly on the VOC reactivity. This demonstrates that for this set of observations the assumption of a uniform ∫ [OH]dt for VOC with different reactivity is not justified and that the observed values for ∫ [OH]dt are the result of mixing of VOC from air masses with different values for ∫ [OH]dt. Based on comparison between carbon isotope ratios and VOC concentration ratios it is also found that the varying influence of sources with different VOC emission ratios has a larger impact on VOC concentration ratios than photochemical processing. It is concluded that for this data set the use of VOC concentration ratios to determine ∫ [OH]dt would result in values for ∫ [OH]dt inconsistent with carbon isotope ratios and that the concept of a uniform ∫ [OH]dt for an air mass has to be replaced by the concept of individual values of an average ∫ [OH]dt for VOC with different reactivity.

  19. 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. PMID:27107611

  20. The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea

    Institute of Scientific and Technical Information of China (English)

    WANG Lisha; ZHANG Chuansong; SHI Xiaoyong

    2015-01-01

    We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic mat-ters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7cm and then de-creased with depth. The peaks were found at depths between 20 to 25cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicat-ing that the organic matter in the sediments was derived mainly from phytoplankton in the seawater.

  1. A molecular organic carbon isotope record of Miocene climate changes

    OpenAIRE

    Schoell, M.; Schouten, S.; Sinninghe Damsté, J.S.; J. W. de Leeuw; Summons, R. E.

    1994-01-01

    The difference in carbon-13 (13C) contents of hopane and sterane biomarkers in the Monterey formation (Naples Beach, California) parallels the Miocene inorganic record of the change in 18O (δ18O), reflecting the Miocene evolution from a well-mixed to a highly stratified photic zone (upper 100 meters) in the Pacific. Steranes (δ13C = 25.4 ± 0.7 per mil versus the Pee Dee belemnite standard) from shallow photic-zone organisms do not change isotopically throughout the Miocene. In contrast, sulfu...

  2. Determining organic carbon distributions in soil particle size fractions as a precondition of lateral carbon transport modeling at large scales

    Science.gov (United States)

    Schindewolf, Marcus; Seher, Wiebke; Pfeffer, Eduard; Schultze, Nico; Amorim, Ricardo S. S.; Schmidt, Jürgen

    2016-04-01

    The erosional transport of organic carbon has an effect on the global carbon budget, however, it is uncertain, whether erosion is a sink or a source for carbon in the atmosphere. Continuous erosion leads to a massive loss of top soils including the loss of organic carbon historically accumulated in the soil humus fraction. The colluvial organic carbon could be protected from further degradation depending on the depth of the colluvial cover and local decomposing conditions. Another part of eroded soils and organic carbon will enter surface water bodies and might be transported over long distances. The selective nature of soil erosion results in a preferential 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. As a precondition of process based lateral carbon flux modeling, carbon distribution on soil particle size fractions has to be known. In this regard the present study refers to the determination of organic carbon contents on soil particle size separates by a combined sieve-sedimentation method for different tropical and temperate soils Our results suggest high influences of parent material and climatic conditions on carbon distribution on soil particle separates. By applying these results in erosion modeling a test slope was simulated with the EROSION 2D simulation software covering certain land use and soil management scenarios referring to different rainfall events. These simulations allow first insights on carbon loss and depletion on sediment delivery areas as well as carbon gains and enrichments on deposition areas on the landscape scale and could be used as a step forward in landscape scaled carbon redistribution modeling.

  3. Natural versus wastewater derived dissolved organic carbon: implications for the environmental fate of organic micropollutants.

    Science.gov (United States)

    Neale, Peta A; Antony, Alice; Gernjak, Wolfgang; Leslie, Greg; Escher, Beate I

    2011-08-01

    The interaction of organic micropollutants with dissolved organic carbon (DOC) can influence their transport, degradation and bioavailability. While this has been well established for natural organic carbon, very little is known regarding the influence of DOC on the fate of micropollutants during wastewater treatment and water recycling. Dissolved organic carbon-water partition coefficients (K(DOC)) for wastewater derived and reference DOC were measured for a range of micropollutants using a depletion method with polydimethylsiloxane disks. For micropollutants with an octanol-water partition coefficient (log K(OW)) greater than 4 there was a significant difference in K(DOC) between reference and wastewater derived DOC, with partitioning to wastewater derived DOC over 1000 times lower for the most hydrophobic micropollutants. The interaction of nonylphenol with wastewater derived DOC from different stages of a wastewater and advanced water treatment train was studied, but little difference in K(DOC) was observed. Organic carbon characterisation revealed that reference and wastewater derived DOC had very different properties due to their different origins. Consequently, the reduced sorption capacity of wastewater derived DOC may be related to their microbial origin which led to reduced aromaticity and lower molecular weight. This study suggests that for hydrophobic micropollutants (log K(OW) > 4) a higher concentration of freely dissolved and thus bioavailable micropollutants is expected in the presence of wastewater derived DOC than predicted using K(DOC) values quantified using reference DOC. The implication is that naturally derived DOC may not be an appropriate surrogate for wastewater derived DOC as a matrix for assessing the fate of micropollutants in engineered systems. PMID:21703657

  4. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    Science.gov (United States)

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO₂-N/L, aerobic P-uptake and oxidation of intercellular poly-β-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO₂-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite. PMID:23771179

  5. 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.

  6. 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

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

    International Nuclear Information System (INIS)

    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

  8. 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.

  9. Carbonate and organic carbon content changes over last 20 ka in the Southeastern Arabian Sea: Paleoceanographic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Narayana, A.C.; Naidu, P.D.; Shinu, N.; Nagabhushanam, P.; Sukhija, B.S.

    Two Gravity cores (AAS 38-4 and AAS 38-5) recovered from the eastern Arabian Sea were analyzed for calcium carbonate (CaCO3), organic carbon, aluminium (Al) and titanium (Ti) in order to understand the calcium carbonate and terrigenous fluctuations...

  10. Young organic matter as a source of carbon dioxide outgassing from Amazonian rivers

    Energy Technology Data Exchange (ETDEWEB)

    Mayorga, E; Aufdenkampe, A K; Masiello, C A; Krusche, A V; Hedges, J I; Quay, P D; Richey, J E; Brown, T A

    2005-06-23

    Rivers are generally supersaturated with respect to carbon dioxide, resulting in large gas evasion fluxes that can be a significant component of regional net carbon budgets. Amazonian rivers were recently shown to outgas more than ten times the amount of carbon exported to the ocean in the form of total organic carbon or dissolved inorganic carbon. High carbon dioxide concentrations in rivers originate largely from in situ respiration of organic carbon, but little agreement exists about the sources or turnover times of this carbon. Here we present results of an extensive survey of the carbon isotope composition ({sup 13}C and {sup 14}C) of dissolved inorganic carbon and three size-fractions of organic carbon across the Amazonian river system. We find that respiration of contemporary organic matter (less than 5 years old) originating on land and near rivers is the dominant source of excess carbon dioxide that drives outgassing in mid-size to large rivers, although we find that bulk organic carbon fractions transported by these rivers range from tens to thousands of years in age. We therefore suggest that a small, rapidly cycling pool of organic carbon is responsible for the large carbon fluxes from land to water to atmosphere in the humid tropics.

  11. Studies on the 4-carbon precursor in the biosynthesis of riboflavin. Purification and properties of L-3,4-dihydroxy-2-butanone-4-phosphate synthase.

    Science.gov (United States)

    Volk, R; Bacher, A

    1990-11-15

    The formation of the riboflavin precursor, 6,7-dimethyl-8-ribityllumazine, from 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione requires a phosphorylated 4-carbon intermediate which has been designated as Compound X (Neuberger, G., and Bacher, A. (1985) Biochem. Biophys. Res. Commun. 127, 175-181). The enzyme catalyzing the formation of Compound X has been purified about 600-fold from the cell extract of the flavinogenic yeast Candida guilliermondii by chromatographic procedures. The purified protein appeared homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and consisted of a single polypeptide of 24 kDa. The committed substrate of the enzyme was identified as D-ribulose 5-phosphate. The enzyme yields two products which were identified as L-3,4-dihydroxy-2-butanone 4-phosphate and formate by NMR and CD spectroscopy. Mg2+ is required for activity. PMID:2246238

  12. Effects of climate change and land management on soil organic carbon dynamics and carbon leaching in northwestern Europe

    NARCIS (Netherlands)

    Stergiadi, Maria; Van Der Perk, Marcel; De Nijs, Ton C M; Bierkens, Marc F P

    2016-01-01

    Climate change and land management practices are projected to significantly affect soil organic carbon (SOC) dynamics and dissolved organic carbon (DOC) leaching from soils. In this modelling study, we adopted the Century model to simulate past (1906-2012), present, and future (2013-2100) SOC and DO

  13. Black Carbon in Estuarine and Coastal Ocean Dissolved Organic Matter

    Science.gov (United States)

    Mannino, Antonio; Harvey, H. Rodger

    2003-01-01

    Black carbon (BC) in ultrafiltered high-molecular-weight DOM (UDOM) was measured in surface waters of Delaware Bay, Chesapeake Bay and the adjacent Atlantic Ocean (USA) to ascertain the importance of riverine and estuarine DOM as a source of BC to the ocean. BC comprised 5-72% of UDOM-C (27+/-l7%) and on average 8.9+/-6.5% of dissolved organic carbon (DOC) with higher values in the turbid region of the Delaware Estuary and lower yields in the river and coastal ocean. The spatial and seasonal distributions of BC along the salinity gradient of Delaware Bay suggest that the higher levels of BC in surface water UDOM originated from localized sources, possibly from atmospheric deposition or released from resuspended sediments. Black carbon comprised 4 to 7% of the DOC in the coastal Atlantic Ocean, revealing that river-estuary systems are important exporters of colloidal BC to the ocean. The annual flux of BC from Delaware Bay UDOM to the Atlantic Ocean was estimated at 2.4x10(exp 10) g BC yr(exp -1). The global river flux of BC through DOM to the ocean could be on the order of 5.5x1O(exp 12)g BC yr (exp -1). These results support the hypothesis that the DOC pool is the intermediate reservoir in which BC ages prior to sedimentary deposition.

  14. Soil Organic Carbon Mapping by Geostatistics in Europe Scale

    Science.gov (United States)

    Aksoy, E.; Panagos, P.; Montanarella, L.

    2013-12-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because SOC is an important soil component that plays key roles in the functions of both natural ecosystems and agricultural systems. The SOC content varies from place to place and it is strongly related with climate variables (temperature and rainfall), terrain features, soil texture, parent material, vegetation, land-use types, and human management (management and degradation) at different spatial scales. Geostatistical techniques allow for the prediction of soil properties using soil information and environmental covariates. In this study, assessment of SOC distribution has been predicted with Regression-Kriging method in Europe scale. In this prediction, combination of the soil samples which were collected from the LUCAS (European Land Use/Cover Area frame statistical Survey) & BioSoil Projects, with local soil data which were collected from six different CZOs in Europe and ten spatial predictors (slope, aspect, elevation, CTI, CORINE land-cover classification, parent material, texture, WRB soil classification, annual average temperature and precipitation) were used. Significant correlation between the covariates and the organic carbon dependent variable was found. Moreover, investigating the contribution of local dataset in watershed scale into regional dataset in European scale was an important challenge.

  15. 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.

  16. 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. PMID:27318445

  17. Implications of Different Worldviews to Assess Soil Organic Carbon Change

    Science.gov (United States)

    Grunwald, S.

    2012-04-01

    Profound shifts have occurred over the last three centuries in which human actions have become the main driver to global environmental change. In this new epoch, the Anthropocene, human-driven changes such as climate and land use change, are pushing the Earth system well outside of its normal operating range causing severe and abrupt environmental change. Changes in land use management and land cover are intricately linked to the carbon cycle, but our knowledge on its spatially and temporally explicit impact on carbon dynamics across different scales is still poorly understood. To elucidate on the magnitude of change in soil organic carbon (SOC) due to human-induced stressors different philosophical worldviews may be considered including (i) empiricism - direct measurements of properties and processes at micro, site-specific or field scales; (ii) metaphysics and ontology - conceptual models to assess soil change (e.g., STEP-AWBH); (iii) epistemology - indirect approaches (e.g., meta-analysis or spectral informed prediction models); (iv) reductionism - e.g., carbon flux measurements; (iv) determinism - mechanistic simulation models and biogeochemical investigations (e.g., Century or DNDC); (v) holism - national or global soil databases and aggregate maps; or (vi) integral - fusing individual, social, economic, cultural and empirical perspectives. The strengths and limitations of each of these philosophical approaches are demonstrated using case examples from Florida and U.S.A. The sensitivity to assess SOC change and uncertainty, backcasting and forecasting ability, scaling potential across space and time domains, and limitations and constraints of different worldviews are discussed.

  18. Dynamics of formation of particles of the condensed carbon phase at shock compression of organic materials

    CERN Document Server

    Fedotov, M G; Luckjanchikov, L A; Lyakhov, N Z; Sharafutdinov, M R; Sheromov, M A; Ten, K A; Titov, V M; Tolochko, B P; Zubkov, P I

    2001-01-01

    Results of the SR study of the density behavior and dynamics of formation of condensed carbon particles at expansion of shock waves in organic materials and some low-sensitive explosives as well as at shock loading of ultra-dispersed diamonds are presented. Appearance of particles of the condensed carbon phase was observed in carbon-rich organic materials.

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

    International Nuclear Information System (INIS)

    To better understand 14C cycling in terrestrial ecosystems, 14C abundances were evaluated for fractionated soil organic matter (SOM) and soil respiration in an urban forest. In 2001 soil profile, Δ 14C 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 14C by atmospheric nuclear weapons testing had penetrated to at least 16 cm depth of mineral soil. The average Δ 14C in atmospheric CO2 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 14C values of residual SOM after acid hydrolysis, the Δ 14C values were slightly lower than those in bulk SOM. This indicates input of 'bomb' C into this organic fraction and higher 14C abundance in acid-soluble SOM. The most of CO2 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 14C abundance at all depths, suggesting no or little incorporation of 'bomb' C to this fraction. Values of Δ 14C 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)

  20. 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 so

  1. Using scratch testing to measure the adhesion strength of calcium phosphate coatings applied to poly(carbonate urethane) substrates.

    Science.gov (United States)

    Barnes, Dunstan; Johnson, Scott; Snell, Robert; Best, Serena

    2012-02-01

    Bioactive coatings are applied to components of modern orthopædic implants to improve the host tissue response to the implants. Such coatings cannot be applied to polymeric implants by high-temperature techniques, because the use of high temperatures may critically degrade the polymer substrate. Regardless of the coating technique that is used, the coating must be sufficiently well adhered to the underlying substrate to provide any practical benefit. This paper investigates the use of scratch testing to measure the adhesion strength of calcium phosphate (CaP) coatings that were applied to a poly(carbonate urethane) (PCU) substrate by an aqueous process at temperatures of 19, 28, 37, and 50 °C. This work represents the first time that scratch testing analysis has been used to study CaP coatings deposited by an aqueous, low-temperature process on to a polymer substrate. Scratch testing was shown to be a useful technique for obtaining comparative, rather than absolute, values of adhesion strength for hard coatings formed on a compliant substrate. Generally, the coating temperature was not found to influence the CaP-PCU adhesion strength. Although CaP coatings formed at 19 °C exhibited considerably lower adhesion strengths than CaP coatings formed at 28, 37, and 50 °C, this finding was attributable to the inconsistency of CaP coatings formed on the PCU substrates at 19 °C. The coating-substrate adhesion strength was measured for CaP coatings of four different coating ages (0, 1, 2, and 3 years). CaP coatings that were aged for 0, 1, or 2 years exhibited similar coating-substrate adhesion strengths to each other. In contrast, CaP coatings that were aged for 3 years demonstrated considerably lower coating-substrate adhesion strengths. The observed reduction in adhesion strength with age was thought to be attributable to suspected "drying out" of the CaP coatings. PMID:22301182

  2. Sodium Phosphate

    Science.gov (United States)

    Sodium phosphate is used in adults 18 years of age or older to empty the colon (large intestine, bowel) ... view of the walls of the colon. Sodium phosphate is in a class of medications called saline ...

  3. 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.

  4. Environmental Controls of Soil Organic Carbon in Soils Across Amazonia

    Science.gov (United States)

    Quesada, Carlos Alberto; Paz, Claudia; Phillips, Oliver; Nonato Araujo Filho, Raimundo; Lloyd, Jon

    2015-04-01

    Amazonian forests store and cycle a significant amount of carbon on its soils and vegetation. Yet, Amazonian forests are now subject to strong environmental pressure from both land use and climate change. Some of the more dramatic model projections for the future of the Amazon predict a major change in precipitation followed by savanization of most currently forested areas, resulting in major carbon losses to the atmosphere. However, how soil carbon stocks will respond to climatic and land use changes depend largely on how soil carbon is stabilized. Amazonian soils are highly diverse, being very variable in their weathering levels and chemical and physical properties, and thus it is important to consider how the different soils of the Basin stabilize and store soil organic carbon (SOC). The wide variation in soil weathering levels present in Amazonia, suggests that soil groups with contrasting pedogenetic development should differ in their predominant mechanism of SOC stabilization. In this study we investigated the edaphic, mineralogical and climatic controls of SOC concentration in 147 pristine forest soils across nine different countries in Amazonia, encompassing 14 different WRB soil groups. Soil samples were collected in 1 ha permanent plots used for forest dynamics studies as part of the RAINFOR project. Only 0-30 cm deep averages are reported here. Soil samples were analyzed for carbon and nitrogen and for their chemical (exchangeable bases, phosphorus, pH) and physical properties, (particle size, bulk density) and mineralogy through standard selective dissolution techniques (Fe and Al oxides) and by semi-quantitative X-Ray diffraction. In Addition, selected soils from each soil group had SOC fractionated by physical and chemical techniques. Our results indicate that different stabilization mechanisms are responsible for SOC stabilization in Amazonian soils with contrasting pedogenetic level. Ferralsols and Acrisols were found to have uniform mineralogy

  5. 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

  6. Study of Bioavailability of Organic Combined State Phosphatic Fertilizers%有机结合态磷肥的生物有效性研究

    Institute of Scientific and Technical Information of China (English)

    和君强; 李菊梅; 马义兵; 方芳

    2014-01-01

    By pot tests on corn, the bioavailabilities of new-type organic combined state phosphatic fertilizers OP1 ( starch-based phosphatic fertilizer ) and OP3 ( straw-based phosphatic fertilizer) are compared.Experimental results show that the effect of new-type organic combined state phosphatic fertilizers on improving corn growth, increase phosphorus content and phosphorus uptake of crops, and increase of fertilizer utilization efficiency is significantly superior to inorganic phosphatic fertilizers.Compared with monocalcium phosphate, the new-type organic combined state phosphatic fertilizer can increase corn phosphorus content by 16.8%~40.0%, and corn phosphorus uptake is doubled, and increase fertilizer utilization ratio by 1.60~2.70 times; compared with sodium pyrophosphate, the new-type organic combined state phosphatic fertilizer can increase corn phosphorus uptake by 41 .9%and corn phosphorus content by 29 .6 %, and increase fertilizer utilization ratio by 61 .9%.Applying half the amount of new-type organic combined state phosphatic fertilizer, it can achieve a desirable effect, it is a new type fertilizer with outstanding advantage and a bright future.%通过玉米盆栽试验,并用传统无机磷肥作为对比,比较了新型有机结合态磷肥OP1(淀粉基磷肥)和OP3(秸秆基磷肥)的生物有效性。试验结果表明:新型有机结合态磷肥在改善玉米长势、增加植株含磷量和吸磷量、提高肥料利用率上的效果明显优于无机磷肥。与磷酸二氢钙相比,有机结合态磷肥可提高玉米含磷量16.8%~40.0%和玉米吸磷量约1.0倍,可提高磷利用率1.60~2.70倍;与焦磷酸钠相比,有机结合态磷肥可提高玉米吸磷量41.9%和玉米含磷量29.6%,可提高磷利用率61.9%。有机结合态磷肥在施用量减半时,即可达到无机磷肥高水平的效果,是一种优势突出、前景光明的新型肥料。

  7. 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.

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

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  9. Effect of electrochemical treatment in H2SO4 aqueous solution on carbon material derived from cellulose with added guanidine phosphate

    Science.gov (United States)

    Tsubota, Toshiki; Wang, Chuanshu; Murakami, Naoya; Ohno, Teruhisa

    2013-03-01

    The electrochemical treatment in a 1 M H2SO4 aqueous solution is applied to the carbon material synthesized from cellulose mixed with guanidine phosphate. The capacitance value increased by the addition of guanidine phosphate; furthermore, the value significantly increased by the electrochemical treatment and was higher than 350 F g-1 at 50 mA g-1. The process used in this study, that is, removing the lignin from wood waste products, such as bamboo, and then mixing with guanidine phosphate before the heat treatment followed by an electrochemical treatment, should be of benefit for the synthesis of a high performance material for the electrodes of electrochemical capacitors. The significant enhancement of the capacitance value appears in the range of 1.5 V∼2.8 V vs. Ag/AgCl for the applied maximum voltage. This voltage range is consistent with the voltage for the significant enhancement of the current value in the CV curve. The change in the capacitance value should be related to the electrochemical reaction of the water electrolysis. The XPS data indicated that the concentrations of both the N atom and the O atom on the surface increased after the electrochemical process.

  10. Variation in assimilable organic carbon formation during chlorination of Microcystis aeruginosa extracellular organic matter solutions.

    Science.gov (United States)

    Sun, Xingbin; Yuan, Ting; Ni, Huishan; Li, Yanpeng; Hu, Yang

    2016-07-01

    This study investigated the chlorination of Microcystis aeruginosa extracellular organic matter (EOM) solutions under different conditions, to determine how the metabolites produced by these organisms affect water safety and the formation of assimilable organic carbon (AOC). The effects of chlorine dosages, coagulant dosage, reaction time and temperature on the formation of AOC were investigated during the disinfection of M.aeruginosa metabolite solutions. The concentration of AOC followed a decreasing and then increasing pattern with increasing temperature and reaction time. The concentration of AOC decreased and then increased with increasing chlorination dosage, followed by a slight decrease at the highest level of chlorination. However, the concentration of AOC decreased continuously with increasing coagulant dosage. The formation of AOC can be suppressed under appropriate conditions. In this study, chlorination at 4mg/L, combined with a coagulant dose of 40mg/L at 20°C over a reaction time of 12hr, produced the minimum AOC. PMID:27372113

  11. Interactions between diatom aggregates, minerals, particulate organic carbon, and dissolved organic matter: Further implications for the ballast hypothesis

    OpenAIRE

    De La Rocha, Christina,; Nowald, N.; Passow, Uta

    2008-01-01

    Correlations of particulate organic carbon (POC) and mineral fluxes into sediment traps in the deep sea have previously suggested that interactions between organic matter and minerals play a key role in organic matter flux to the deep. Here experiments were carried out in rolling tanks to observe the incorporation of suspended biogenic minerals ( calcium carbonate coccoliths or silica diatom frustules) into diatom aggregates and examine their influence on aggregate character. Addition of high...

  12. The impact of recycling of organic carbon on the stable carbon isotopic composition of dissolved inorganic carbon in a stratified marine system (Kyllaren fjord, Norway)

    NARCIS (Netherlands)

    Breugel, Y. van; Schouten, S.; Paetzel, M.; Nordeide, R.; Sinninghe Damsté, J.S.

    2005-01-01

    A negative carbon isotope shift in sedimentary organic carbon deposited in stratified marine and lacustrine systems has often been inferred to be a consequence of the process of recycling of respired and, therefore, 13C-depleted, dissolved inorganic carbon (DIC) formed from mineralization of descend

  13. How will conversion to organic cereal production affect carbon stocks in Swedish agricultural soils?

    OpenAIRE

    Andrén, Olof; Kätterer, Thomas; Kirchmann, Holger

    2008-01-01

    Soil carbon changes were modelled over 30 years with the focus on cereal crops, since leys are often managed similarly in organic and conventional agriculture. Other crops were not considered due to difficulties in large-scale cropping of oilseed rape and potatoes organically because of pest problems. Four scenarios were used: 0%, 8% (current), 20% and 100% organic cereal production. Conversion to organic cereal crop production was found to reduce the amount of carbon stored as organic matter...

  14. 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

  15. Treatment of hydroponic wastewater by denitrification filters using plant prunings as the organic carbon source.

    Science.gov (United States)

    Park, J B K; Craggs, R J; Sukias, J P S

    2008-05-01

    This study investigated the feasibility of using pre-treated plant liquors as organic carbon sources for the treatment of hydroponic wastewater containing high nitrate-N (>300 mg N/L). The waste plant material was pre-treated to extract organic carbon-rich liquors. When this plant liquor was used as an organic carbon source in denitrification filters at the organic carbon:nitrogen dose rate of 3C:N, nitrate removal efficiencies were >95% and final effluent nitrate concentrations were consistently 140 mg/L) of organic carbon (fBOD5) remained in the final effluents. Therefore, a 'compromise' organic carbon:nitrogen dose rate (2C:N) was trialled, at which nitrate removal efficiencies were maintained at >85%, final effluent nitrate concentrations were consistently below 45 mg N/L, and effluent fBOD5 concentrations were hydroponic wastewater in a denitrification filter. PMID:17714940

  16. Mineland reclamation and soil organic carbon sequestration in Ohio

    International Nuclear Information System (INIS)

    The mining industry has been continuously involved in initiatives to reduce the emission of green house gases in to atmosphere. Control measures have been introduced in all steps starting from the mining of coal to energy production. Reclamation of mined land was and is one of the eco-friendly measures adopted by the industry. Apart from the inherent benefits of reclamation to improve on and offsite environmental quality, its potential to produce biomass and enhance soil organic carbon (SOC) has not been addressed. Reclamative effects of establishing forest and pasture with (graded) and without topsoil (ungraded) application on soil quality and soil carbon sequestration was studied on mine land in Ohio. The SOC pool for 0--30 cm depth for the undisturbed control sites was 56.6 MgC/ha for forest and 66.3 MgC/ha for pasture. In comparison, the SOC pool in the forest and pasture of graded mineland for 0--30 cm depth after 25 years of reclamation was 58.9 MgC/ha and 62.7 MgC/ha respectively. In ungraded mineland, the SOC pool in the 0--30 cm depth after 30 years of reclamation was 51.5 MgC/ha in forest and 58.9 MgC/ha in the pasture

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

    Science.gov (United States)

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

    2016-05-01

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

  18. Organic carbon isotopes of the Sinian and Early Cambrian black shales on Yangtze Platform, China

    Institute of Scientific and Technical Information of China (English)

    李任伟; 卢家烂; 张淑坤; 雷加锦

    1999-01-01

    Organic matter of the Sinian and early Cambrian black shales on the Yangtze Platform belongs to the light carbon group of isotopes with the δ13C values from - 27 % to -35 % , which are lower than those of the contemporaneously deposited carbonates and phosphorites. A carbon isotope-stratified paleooceanographic model caused by upwelling is proposed, which can be used not only to interpret the characteristics of organic carbon isotopic compositions of the black shales, but also to interpret the paleogeographic difference in the organic carbon isotope compositions of various types of sedimentary rocks.

  19. 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)) (pdensity and the environmental/anthropogenic factors (R(2)=0.59). The soil pH, land use, and elevation are the most important factors for determining SOC dynamics. In contrast, the effect of the reclamation age on the SOC density is negligible, where SOC content in the land reclaimed during years 1047-1724 is as low as that reclaimed during years 1945-2004. The scenario analysis results indicate that the carbon 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. PMID:27196991

  20. Metal organic frameworks/macroporous carbon composites with enhanced stability properties and good electrocatalytic ability for ascorbic acid and hemoglobin.

    Science.gov (United States)

    Zhang, Yufan; Nsabimana, Anaclet; Zhu, Liande; Bo, Xiangjie; Han, Ce; Li, Mian; Guo, Liping

    2014-11-01

    The thermal, water and electrochemical stability of Cu-based metal organic frameworks (Cu-MOFs) confined in macroporous carbon (MPC) hybrids has been investigated. Thermogravimetric analyses, X-Ray diffraction, scanning electron microscopy, and cyclic voltammetry were employed to confirm the stability of pure Cu-MOFs, MPC, and Cu-MOFs-MPC. As compared to pure Cu-MOFs, the porous composite materials of MPC and Cu-MOFs interact and seem to form new materials having homogenous structure and chemistry, which show structural stability in aqueous media and electrochemical stability in phosphate buffer solution (PBS pH 7.4). The detection of ascorbic acid and hemoglobin is performed as an electrochemical probe, indicating Cu-MOFs-MPC holds great promise for the design of electrochemical sensors.

  1. Dynamics of organic and inorganic carbon across contiguous mangrove and seagrass systems (Gazi Bay, Kenya)

    OpenAIRE

    BOUILLON, S; F. Dehairs; Velimirov, B.; Abril, G.; Borges, A. V.

    2007-01-01

    [1] 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 column, and could be distinguished on the basis of their delta C-13 signatures and particulate organic carbon: total suspended matter (POC/TSM) ratios. Spatially, a distinct boundary existed whereb...

  2. In vitro and in vivo degradation of biomimetic octacalcium phosphate and carbonate apatite coatings on titanium implants

    NARCIS (Netherlands)

    Barrere, F.; Valk, van der C.M.; Dalmeijer, R.A.J.; Blitterswijk, van C.A.; Groot, de K.; Layrolle, P.

    2003-01-01

    Calcium phosphate (Ca-P) coatings have been applied onto titanium alloys prosthesis to combine the srength of metals with the bioactivity of Ca-P. It has been clearly shown in many publications that Ca-P coating accelerates bone formation around the implant. However, longevity of the Ca-P coating fo

  3. 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.

  4. Multicore-shell carbon-coated lithium manganese phosphate and lithium vanadium phosphate composite material with high capacity and cycling performance for lithium-ion battery

    International Nuclear Information System (INIS)

    The energy crisis and energy security leads a great attention to Li-ion batteries (LIB) as the excellent power candidates. We successfully synthesized LiMnPO4·Li3V2(PO4)3/C composite cathode material with high capacity and excellent cycling performance from prickly MnV2O6·2H2O precursor, following chemical reduction and lithiation with double carbon sources. The LiMnPO4·Li3V2(PO4)3/C sample has a special multicore-shell structure, whose inner stuffing are LiMnPO4 and Li3V2(PO4)3 in the range of 5-25nm. The initial discharge capacity of LiMnPO4·Li3V2(PO4)3/C composite delivers 221.4 mAh g−1, 202.3 mAh g−1 and 152.9 mAh g−1 at the rate of 0.1C, 1C and 5C in the range of 1.5-4.5 V, and retains 99.5%, 99.1% and 94.3% of its initial discharge capacity after 50 cycles, respectively

  5. Application of Two Exponential Equations in the Study of Soil Organic Carbon Mineralization in Natural Forests

    Directory of Open Access Journals (Sweden)

    Pang Huan

    2014-10-01

    Full Text Available This study respective using the exponential equation and double exponential equation which are widely used were fitted Pinus massoniana, evergreen broad leaved forest, deciduous oak forest, pine-oak forest, Pinus koraiensis and Pinus tabulaeformis and other six kinds of typical natural forest soil organic carbon mineralization process, it also by fitting curves and cumulative release of CO2 mineralization process analysis and correlation of inert carbon content of soil measured and fitted values of t-test analysis, the two exponential equations in natural forest soil organic carbon mineralization process the application results were evaluated. The results show that the double exponential equation on soil organic carbon mineralization has a better fitting description effect can be more realistically reflect the changes in soil organic carbon mineralization characteristics of the fitting results of insert soil carbon content and measured values a significant difference is not level, the soil can be more accurately reflect the changes of the inert carbon.

  6. Selective Sorption of Dissolved Organic Carbon Compounds by Temperate Soils

    Energy Technology Data Exchange (ETDEWEB)

    Jagadamma, Sindhu [ORNL; Mayes, Melanie [ORNL; Phillips, Jana Randolph [ORNL

    2012-01-01

    Physico-chemical sorption of dissolved organic carbon (DOC) on soil minerals is one of the major processes of organic carbon (OC) stabilization in soils, especially in deeper layers. The attachment of C on soil solids is related to the reactivity of the soil minerals and the chemistry of the sorbate functional groups, but the sorption studies conducted without controlling microbial activity may overestimate the sorption potential of soil. This study was conducted to examine the sorptive characteristics of a diverse functional groups of simple OC compounds (D-glucose, L-alanine, oxalic acid, salicylic acid, and sinapyl alcohol) on temperate climate soil orders (Mollisols, Ultisols and Alfisols) with and without biological degradative processes. Equilibrium batch experiments were conducted using 0-100 mg C L-1 at a solid-solution ratio of 1:60 for 48 hrs and the sorption parameters were calculated by Langmuir model fitting. The amount of added compounds that remained in the solution phase was detected by high performance liquid chromatography (HPLC) and total organic C (TOC) analysis. Soil sterilization was performed by -irradiation technique and experiments were repeated to determine the contribution of microbial degradation to apparent sorption. Overall, Ultisols did not show a marked preference for apparent sorption of any of the model compounds, as indicated by a narrower range of maximum sorption capacity (Smax) of 173-527 mg kg soil-1 across compounds. Mollisols exhibited a strong preference for apparent sorption of oxalic acid (Smax of 5290 mg kg soil-1) and sinapyl alcohol (Smax of 2031 mg kg soil-1) over the other compounds. The propensity for sorption of oxalic acid is mainly attributed to the precipitation of insoluble Ca-oxalate due to the calcareous nature of most Mollisol subsoils and its preference for sinapyl alcohol could be linked to the polymerization of this lignin monomer on 2:2 mineral dominated soils. The reactivity of Alfisols to DOC was in

  7. 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)

    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. 210Po and 210Pb 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 210Po and 210Pb concentrations observed in sediment were found to be 170 Bq.kg-1and 64 Bq.kg-1 respectively. While, 210Pb and 210Po 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 (226Ra = 33.2 Bq.kg-1 and 234Th = 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 210Po and 210Pb 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 210Po and 210Pb 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 210Pb with depth, where the constant supply dating method can not be applied. This is due to the fact that two sources for unsupported 210Pb being observed in the port area; viz. radon gas and phosphate dust carrying radioactivity including 210Pb. However, depth

  8. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation.

    Science.gov (United States)

    Wei, Mingyu; Gao, Long; Li, Jun; Fang, Jia; Cai, Wenxuan; Li, Xiaoxia; Xu, Aihua

    2016-10-01

    Graphitic carbon nitride supported on activated carbon (g-C3N4/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-C3N4 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-C3N4 to CO was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C3N4/AC catalyst within 20min with PMS, while g-C3N4+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C3N4 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 SO4(-)) in AO7 oxidation was proposed in the system. The CO 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.

  9. Activation of peroxymonosulfate by graphitic carbon nitride loaded on activated carbon for organic pollutants degradation.

    Science.gov (United States)

    Wei, Mingyu; Gao, Long; Li, Jun; Fang, Jia; Cai, Wenxuan; Li, Xiaoxia; Xu, Aihua

    2016-10-01

    Graphitic carbon nitride supported on activated carbon (g-C3N4/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-C3N4 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-C3N4 to CO was also observed from XPS spectra. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the g-C3N4/AC catalyst within 20min with PMS, while g-C3N4+PMS and AC+PMS showed no significant activity for the reaction. The performance of the catalyst was significantly influenced by the amount of g-C3N4 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 SO4(-)) in AO7 oxidation was proposed in the system. The CO 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. PMID:27214000

  10. 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

  11. RT-MATRIX: Measuring Total Organic Carbon by Photocatalytic Oxidation of Volatile Organic Compounds

    Science.gov (United States)

    2008-01-01

    Volatile organic compounds (VOCs) inevitably accumulate in enclosed habitats such as the International Space Station and the Crew Exploration Vehicle (CEV) as a result of human metabolism, material off-gassing, and leaking equipment. Some VOCs can negatively affect the quality of the crew's life, health, and performance; and consequently, the success of the mission. Air quality must be closely monitored to ensure a safe living and working environment. Currently, there is no reliable air quality monitoring system that meets NASA's stringent requirements for power, mass, volume, or performance. The ultimate objective of the project -- the development of a Real-Time, Miniaturized, Autonomous Total Risk Indicator System (RT.MATRIX).is to provide a portable, dual-function sensing system that simultaneously determines total organic carbon (TOC) and individual contaminants in air streams.

  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. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Zeikus, J.G.; Jain, M.

    1993-12-31

    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  14. Organic carbon stock in topsoil of Jiangsu Province, China, and the recent trend of carbon sequestration

    Institute of Scientific and Technical Information of China (English)

    PAN Gen-xing; LI Lian-qing; ZHANG Qi; WANG Xu-kui; SUN Xing-bin; XU Xiao-bo; JIANG Ding-an

    2005-01-01

    Data collection of soil organic carbon(SOC) of 154 soil series of Jiangsu, China from the second provincial soil survey and of recent changes in SOC from a number of field pilot experiments across the province were collected. Statistical analysis of SOC contents and soil properties related to organic carbon storage were performed. The provincial total topsoil SOC stock was estimated to be 0.1 Pg with an extended pool of 0.4 Pg taking soil depth of 1 m, being relatively small compared to its total land area of 101700 km2 . One quarter of this topsoil stock was found in the soils of the Taihu Lake region that occupied 1/6 of the provincial arable area. Paddy soils accounted for over 50% of this stock in terms of SOC distribution among the soil types in the province. Experimental data from experimental farms widely distributed in the province showed that SOC storage increased consistently over the last 20 years despite a previously reported decreasing tendency during the period between 1950-1970. The evidence indicated that agricultural management practices such as irrigation, straw return and rotation of upland crops with rice or wheat crops contributed significantly to the increase in SOC storage. The annual carbon sequestration rate in the soils was in the range of 0.3-3.5 tC/( hm2 · a), depending on cropping systems and other agricultural practices. Thus, the agricultural production in the province, despite the high input, could serve as one of the practical methods to mitigate the increasing air CO2.

  15. Organic acid production and plant growth promotion as a function of phosphate solubilization by Acinetobacter rhizosphaerae strain BIHB 723 isolated from the cold deserts of the trans-Himalayas.

    Science.gov (United States)

    Gulati, Arvind; Sharma, Natasha; Vyas, Pratibha; Sood, Swati; Rahi, Praveen; Pathania, Vijaylata; Prasad, Ramdeen

    2010-11-01

    An efficient phosphate-solubilizing plant growth-promoting Acinetobacter rhizosphaerae strain BIHB 723 exhibited significantly higher solubilization of tricalcium phosphate (TCP) than Udaipur rock phosphate (URP), Mussoorie rock phosphate (MRP) and North Carolina rock phosphate (NCRP). Qualitative and quantitative differences were discerned in the gluconic, oxalic, 2-keto gluconic, lactic, malic and formic acids during the solubilization of various inorganic phosphates by the strain. Gluconic acid was the main organic acid produced during phosphate solubilization. Formic acid production was restricted to TCP solubilization and oxalic acid production to the solubilization of MRP, URP and NCRP. A significant increase in plant height, shoot fresh weight, shoot dry weight, root length, root dry weight, and root, shoot and soil phosphorus (P) contents was recorded with the inoculated treatments over the uninoculated NP(0)K or NP(TCP)K treatments. Plant growth promotion as a function of phosphate solubilization suggested that the use of bacterial strain would be a beneficial addition to the agriculture practices in TCP-rich soils in reducing the application of phosphatic fertilizers.

  16. Bioavailability of dissolved organic carbon linked with the regional carbon cycle in the East China Sea

    Science.gov (United States)

    Gan, Shuchai; Wu, Ying; Zhang, Jing

    2016-02-01

    The regional carbon cycle on continental shelves has created great interest recently due to the enigma of whether these areas are a carbon sink or a source. It is vital for a precise carbon cycle model to take the bioavailability of dissolved organic carbon (DOC) into account, as it impacts the sink and source capacity, especially on dynamic shelves such as the East China Sea. Nine bio-decomposition experiments were carried out to assess differences in the bioavailability of DOC. Samples were collected from different water masses in the East China Sea, such as the Coastal Current, the Taiwan Current, and the Kuroshio Current, as well as from the Changjiang (Yangtze River), the main contributor of terrestrial DOC in the East China Sea. This study aimed to quantify and qualify bioavailable DOC (BDOC) in the East China Sea. Both the degradation constant of BDOC and the carbon output from microorganisms have been quantitatively evaluated. Qualitatively, excitation-emission matrix fluorescence spectra (EEMs) were used to evaluate the intrinsic reasons for BDOC variation. By using EEMs in conjunction with parallel factor analysis (PARAFAC), five individual fluorescent components were identified in this study: three humic-like and two protein-like components (P1, P2). The highest P1 and P2 fluorescence intensities were recorded in the coastal water during a phytoplankton algal bloom, while the lowest intensities were recorded in the Changjiang estuary. Quantitatively, BDOC observed during the incubation ranged from 0 to 26.1 μM. The DOC degradation rate constant varied from 0 to 0.027 (d-1), and was lowest in the Changjiang and highest in algal bloom water and warm shelf water (the Taiwan current). The Taiwan Current and mixed shelf water were the major contributors of BDOC flux to the open ocean, and the East China Sea was a net source of BDOC to the ocean. The results verified the importance of BDOC in regional carbon cycle modeling. Combining the data of BDOC and EEMs

  17. Impact of total organic carbon (in sediments) and dissolved organic carbon (in overlying water column) on Hg sequestration by coastal sediments from the central east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Chakrabortya, P.; Sharma, B.M.; Babu, P.V.R.; Yao, K.M.; Jaychandran, S.

          1.0 Introduction Mercury (Hg) has received a worldwide attention due to its significant global adverse impact on both environment and human health (Boening, 2000; Ratcliffe et al., 1996; Wolfe et al., 2009). Due to its high toxicity... of dissolved organic carbon and salinity on bioavailability of mercury. Applied and Environmental Microbiology, 63, 4267–4271. Bengtsson, G., Picado, F., 2008. Mercury sorption to sediments: Dependence on grain size, dissolved organic carbon, and suspended...

  18. 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

  19. Organic Geochemistry of the Hamersley Province: Relationships Among Organic Carbon Isotopes, Molecular Fossils, and Lithology

    Science.gov (United States)

    Eigenbrode, Jennifer L.

    2012-01-01

    Molecular fossils are particularly valuable ancient biosignatures that can provide key insight about microbial sources and ecology in early Earth studies. In particular, hopanes carrying 2-methyl or 3-methyl substituents are proposed to be derived from cyanobacteria and oxygen-respiring methanotrophs, respectively, based on both their modem occurrences and their Proterozoic and Phanerozoic sedimentary distributions. Steranes are likely from ancestral eukaryotes. The distribution of methylhopanes, steranes, and other biomarkers in 2.72-2.56 billion-year-old rocks from the Hamersley Province, Western Australia show relationships to lithology, facies, and isotopes of macromolecular carbon, and other biomarkers. These observations support biomarker syngenicity and thermal maturity. Moreover, ecological signatures are revealed, including a surprising relationship between isotopic values for bulk macromolecular carbon and the biomarker for methanotrophs. The record suggests that cyanobacteria were likely key organisms of shallow-water microbial ecosystems providing molecular oxygen, fixed carbon, and possibly fixed nitrogen, and methanotrophs were not alone in recycling methane and other C-13-depleted substrates.

  20. Light absorption by organic carbon from wood combustion

    Directory of Open Access Journals (Sweden)

    Y. Chen

    2010-02-01

    Full Text Available Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While black carbon (BC is highly absorbing, some organic carbon (OC also has significant absorption, especially at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to positive direct aerosol radiative forcing. Quantification of that absorption is necessary so that radiative-transfer models can evaluate the net radiative effect of OC.

    In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble OC contributes to light absorption at both ultraviolet and visible wavelengths. However, a larger portion of the absorption comes from OC that is extractable only by methanol. Absorption spectra of water-soluble OC are similar to literature reports. We compare spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating OC with higher absorption; changing wood temperature from a devolatilizing state of 210 °C to a near-flaming state of 360 °C causes about a factor of four increase in mass-normalized absorption at visible wavelengths. A clear-sky radiative transfer model suggests that, despite the absorption, both high-temperature and low-temperature OC result in negative top-of-atmosphere radiative forcing over a surface with an albedo of 0.19 and positive radiative forcing over bright surfaces. Unless absorption by real ambient aerosol is higher than that measured here, it probably affects global average clear-sky forcing very little, but could be important in energy balances over bright

  1. Clay:organic-carbon and organic carbon as determinants of the soil physical properties: reassessment of the Complexed Organic Carbon concept

    Science.gov (United States)

    Matter, Adrien; Johannes, Alice; Boivin, Pascal

    2016-04-01

    Soil Organic Carbon (SOC) is well known to largely determine the soil physical properties and fertility. Total porosity, structural porosity, aeration, structural stability among others are reported to increase linearly with increasing SOC in most studies. Is there an optimal SOC content as target in soil management, or is there no limit in physical fertility improvement with SOC? Dexter et al. (2008) investigated the relation between clay:SOC ratio and the physical properties of soils from different databases. They observed that the R2 of the relation between SOC and the physical properties were maximized when considering the SOC fraction limited to a clay:SOC ratio of 10. They concluded that this fraction of the SOC was complexed, and that the additional SOC was not influencing the physical properties as strongly as the complexed one. In this study, we reassessed this approach, on a database of 180 undisturbed soil samples collected from cambiluvisols of the Swiss Plateau, on an area of 2400 km2, and from different soil uses. The physical properties were obtained with Shrinkage Analysis, which involved the parameters used in Dexter et al., 2008. We used the same method, but detected biases in the statistical approach, which was, therefore, adapted. We showed that the relation between the bulk density and SOC was changing with the score of visual evaluation of the structure (VESS) (Ball et al., 2007). Therefore, we also worked only on the "good" structures according to VESS. All shrinkage parameters were linearly correlated to SOC regardless of the clay:SOC ratio, with R2 ranging from 0.45 to 0.8. Contrarily to Dexter et al. (2008), we did not observed an optimum in the R2 of the relation when considering a SOC fraction based on the clay:SOC ratio. R2 was increasing until a Clay:SOC of about 7, where it reached, and kept, its maximum value. The land use factor was not significant. The major difference with the former study is that we worked on the same soil group

  2. Synthesis and structural characterization of zirconium phosphate adipate dimethyl sulphoxide: A new lambda-type organic-inorganic layered material

    Indian Academy of Sciences (India)

    Hussein Alhendawi

    2014-07-01

    −Zirconium phosphate adipate dimethyl sulphoxide, -ZrPO4(OOC-(CH2)4-COOH)(CH3)2SO, is prepared by means of topotactic anion exchange of the chloride ligand of -Zirconium phosphate, -ZrPO4Cl(CH3)2SO, with adipate. The samples are characterized by thermal analyses, X-ray diffractometry and FT-IR spectrophotometry. The used analysis approaches provide strong evidence that the chloride monovalent anions of -Zirconium phosphate are completely exchanged with the carboxylate groups of the adipate monoanionic ligands. Moreover, the adipate ligands replace the chloride anions in a 1:1 stoichiometry. In this case the formula of the derivative should contain the monoanionic adipate fragment: (OOC-(CH2)4-COOH). This formula is in agreement with TGA and elemental analysis. With respect to intercalation properties, the synthesized adipate-solid phase has a higher acidic character and a larger gallery height in comparison to the pristine -Zirconium phosphate (1.47, 1.02 nm, respectively). Therefore, this material is expected to be a suitable host for intercalation of huge basic guests.

  3. [Effects of different fertilization modes on paddy field topsoil organic carbon content and carbon sequestration duration in South China].

    Science.gov (United States)

    Zhu, Li-Qun; Yang, Min-Fang; Xu, Min-Lun; Zhang, Wu-Yi; Bian, Xin-Min

    2012-01-01

    Based on the organic carbon data of 222 topsoil samples taken from 38 paddy field experiment sites in South China, calculations were made on the relative annual change of topsoil organic carbon content (RAC) and carbon sequestration duration in the paddy fields in South China under five fertilization modes (inorganic nitrogen fertilization, N; inorganic nitrogen and phosphorus fertilization, NP; inorganic nitrogen, phosphorus, and potassium fertilization, NPK; organic fertilization, O; and inorganic plus organic fertilization, OF). The RAC under the fertilizations was 0-0.4 g x kg(-1) x a(-1), with an increment of 0.20 and 0.26 g x kg(-1) x a(-1) in double and triple cropping systems, respectively. The RAC was higher in treatments O and OF than in treatments N, NP, and NPK, being the highest (0.32 g x kg(-1) x a(-1)) in treatment OF. The topsoil organic carbon accumulation rate decreased with increasing time, and the carbon sequestration duration in treatments N, NP, NPK, O, and OF was about 22, 28, 38, 57, and 54 years, respectively. Inorganic plus organic fertilization was the most effective practice for soil carbon sequestration in the paddy fields in South China.

  4. Role of Organic Matter and Carbonates in Soil Aggregation Estimated Using Laser Diffractometry

    Institute of Scientific and Technical Information of China (English)

    I. VIRTO; N. GARTZIA-BENGOETXEA; O. FERN(A)NDEZ-UGALDE

    2011-01-01

    Aggregation in many soils in semi-arid land is affected by their high carbonate contents.The presence of lithogenic and/or primary carbonates can also influence the role of soil organic matter (SOM) in aggregation.The role of carbonates and SOM in aggregation was evaluated by comparing the grain-size distribution in two carbonate-rich soils (15% and 30% carbonates) under conventional tillage after different disaggregating treatments.We also compared the effect of no-tillage and conventional tillage on the role of these two aggregating agents in the soil with 30% of carbonates.Soil samples were treated as four different ways:shaking with water (control),adding hydrochloric acid (HCl) to remove carbonates,adding hydrogen peroxide (H2O2) to remove organic matter,and consecutive removal of carbonates and organic matter (HCl +H2O2),and then analyzed by laser diffraction grain-sizing.The results showed that different contributions of carbonates and SOM to aggregate formation and stability depended not only on their natural proportion,but also on the soil type,as expressed by the major role of carbonates in aggregation in the 15% carbonate-rich soil,with a greater SOC-to-SIC (soil organic C to soil inorganic C) ratio than the 30% carbonate-rich soil.The increased organic matter stocks under no-tillage could moderate the role of carbonates in aggregation in a given soil,which meant that no-tillage could affect the organic and the inorganic C cycles in the soil.In conclusion,the relative role of carbonates and SOM in aggregation could alter the aggregates hierarchy in carbonate-rich soils.

  5. Combining Soil Databases for Topsoil Organic Carbon Mapping in Europe.

    Science.gov (United States)

    Aksoy, Ece; Yigini, Yusuf; Montanarella, Luca

    2016-01-01

    Accuracy in assessing the distribution of soil organic carbon (SOC) is an important issue because of playing key roles in the functions of both natural ecosystems and agricultural systems. There are several studies in the literature with the aim of finding the best method to assess and map the distribution of SOC content for Europe. Therefore this study aims searching for another aspect of this issue by looking to the performances of using aggregated soil samples coming from different studies and land-uses. The total number of the soil samples in this study was 23,835 and they're collected from the "Land Use/Cover Area frame Statistical Survey" (LUCAS) Project (samples from agricultural soil), BioSoil Project (samples from forest soil), and "Soil Transformations in European Catchments" (SoilTrEC) Project (samples from local soil data coming from six different critical zone observatories (CZOs) in Europe). Moreover, 15 spatial indicators (slope, aspect, elevation, compound topographic index (CTI), CORINE land-cover classification, parent material, texture, world reference base (WRB) soil classification, geological formations, annual average temperature, min-max temperature, total precipitation and average precipitation (for years 1960-1990 and 2000-2010)) were used as auxiliary variables in this prediction. One of the most popular geostatistical techniques, Regression-Kriging (RK), was applied to build the model and assess the distribution of SOC. This study showed that, even though RK method was appropriate for successful SOC mapping, using combined databases was not helpful to increase the statistical significance of the method results for assessing the SOC distribution. According to our results; SOC variation was mainly affected by elevation, slope, CTI, average temperature, average and total precipitation, texture, WRB and CORINE variables for Europe scale in our model. Moreover, the highest average SOC contents were found in the wetland areas; agricultural

  6. Combining Soil Databases for Topsoil Organic Carbon Mapping in Europe.

    Directory of Open Access Journals (Sweden)

    Ece Aksoy

    Full Text Available Accuracy in assessing the distribution of soil organic carbon (SOC is an important issue because of playing key roles in the functions of both natural ecosystems and agricultural systems. There are several studies in the literature with the aim of finding the best method to assess and map the distribution of SOC content for Europe. Therefore this study aims searching for another aspect of this issue by looking to the performances of using aggregated soil samples coming from different studies and land-uses. The total number of the soil samples in this study was 23,835 and they're collected from the "Land Use/Cover Area frame Statistical Survey" (LUCAS Project (samples from agricultural soil, BioSoil Project (samples from forest soil, and "Soil Transformations in European Catchments" (SoilTrEC Project (samples from local soil data coming from six different critical zone observatories (CZOs in Europe. Moreover, 15 spatial indicators (slope, aspect, elevation, compound topographic index (CTI, CORINE land-cover classification, parent material, texture, world reference base (WRB soil classification, geological formations, annual average temperature, min-max temperature, total precipitation and average precipitation (for years 1960-1990 and 2000-2010 were used as auxiliary variables in this prediction. One of the most popular geostatistical techniques, Regression-Kriging (RK, was applied to build the model and assess the distribution of SOC. This study showed that, even though RK method was appropriate for successful SOC mapping, using combined databases was not helpful to increase the statistical significance of the method results for assessing the SOC distribution. According to our results; SOC variation was mainly affected by elevation, slope, CTI, average temperature, average and total precipitation, texture, WRB and CORINE variables for Europe scale in our model. Moreover, the highest average SOC contents were found in the wetland areas

  7. Rapid Assessment of U.S. Forest and Soil Organic Carbon Storage and Forest Biomass Carbon-Sequestration Capacity

    Science.gov (United States)

    Sundquist, Eric T.; Ackerman, Katherine V.; Bliss, Norman B.; Kellndorfer, Josef M.; Reeves, Matt C.; Rollins, Matthew G.

    2009-01-01

    This report provides results of a rapid assessment of biological carbon stocks and forest biomass carbon sequestration capacity in the conterminous United States. Maps available from the U.S. Department of Agriculture are used to calculate estimates of current organic carbon storage in soils (73 petagrams of carbon, or PgC) and forest biomass (17 PgC). Of these totals, 3.5 PgC of soil organic carbon and 0.8 PgC of forest biomass carbon occur on lands managed by the U.S. Department of the Interior (DOI). Maps of potential vegetation are used to estimate hypothetical forest biomass carbon sequestration capacities that are 3-7 PgC higher than current forest biomass carbon storage in the conterminous United States. Most of the estimated hypothetical additional forest biomass carbon sequestration capacity is accrued in areas currently occupied by agriculture and development. Hypothetical forest biomass carbon sequestration capacities calculated for existing forests and woodlands are within +or- 1 PgC of estimated current forest biomass carbon storage. Hypothetical forest biomass sequestration capacities on lands managed by the DOI in the conterminous United States are 0-0.4 PgC higher than existing forest biomass carbon storage. Implications for forest and other land management practices are not considered in this report. Uncertainties in the values reported here are large and difficult to quantify, particularly for hypothetical carbon sequestration capacities. Nevertheless, this rapid assessment helps to frame policy and management discussion by providing estimates that can be compared to amounts necessary to reduce predicted future atmospheric carbon dioxide levels.

  8. Predictive mapping of soil organic carbon in wet cultivated lands using classification-tree based models

    DEFF Research Database (Denmark)

    Kheir, Rania Bou; Greve, Mogens Humlekrog; Bøcher, Peder Klith;

    2010-01-01

    Soil organic carbon (SOC) is one of the most important carbon stocks globally and has large potential to affect global climate. Distribution patterns of SOC in Denmark constitute a nation-wide baseline for studies on soil carbon changes (with respect to Kyoto protocol). This paper predicts and maps...

  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 effect

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

    NARCIS (Netherlands)

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

    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 s

  11. Carbonate concretions as a significant component of ancient marine carbon cycles: Insights from paired organic and inorganic carbon isotope analyses of a Cretaceous shale

    Science.gov (United States)

    Loyd, S. J.

    2014-12-01

    Carbonate concretions often occur within fine-grained, organic-rich sedimentary rocks. This association reflects the common production of diagenetic minerals through biologic cycling of organic matter. Chemical analysis of carbonate concretions provides the rare opportunity to explore ancient shallow diagenetic environments, which are inherently transient due to progressive burial but are an integral component of the marine carbon cycle. The late Cretaceous Holz Shale (~80 Ma) contains abundant calcite concretions that exhibit textural and geochemical characteristics indicative of relatively shallow formation (i.e., near the sediment-water interface). Sampled concretions contain between 5.4 and 9.8 wt.% total inorganic carbon (TIC), or ~45 and 82 wt.% CaCO3, compared to host shale values which average ~1.5 wt.% TIC. Organic carbon isotope compositions (δ13Corg) are relatively constant in host and concretion samples ranging from ­-26.3 to -24.0‰ (VPDB). Carbonate carbon isotope compositions (δ13Ccarb) range from -22.5 to -3.4‰, indicating a significant but not entirely organic source of carbon. Concretions of the lower Holz Shale exhibit considerably elevated δ13Ccarb values averaging -4.8‰, whereas upper Holz Shale concretions express an average δ13Ccarb value of -17.0‰. If the remaining carbonate for lower Holz Shale concretions is sourced from marine fluids and/or dissolved marine carbonate minerals (e.g., shells), a simple mass balance indicates that ~28% of concretion carbon was sourced from organic matter and ~72% from late Cretaceous marine inorganic carbon (with δ13C ~ +2.5‰). Upper Holz Shale calculations indicate a ~73% contribution from organic matter and a ~27% contribution from inorganic carbon. When normalized for carbonate, organic contents within the concretions are ~2-13 wt.% enriched compared to host contents. This potentially reflects the protective nature of cementation that acts to limit permeability and chemical destruction of

  12. Bimetallic Metal-Organic Frameworks for Controlled Catalytic Graphitization of Nanoporous Carbons

    Science.gov (United States)

    Tang, Jing; Salunkhe, Rahul R.; Zhang, Huabin; Malgras, Victor; Ahamad, Tansir; Alshehri, Saad M.; Kobayashi, Naoya; Tominaka, Satoshi; Ide, Yusuke; Kim, Jung Ho; Yamauchi, Yusuke

    2016-07-01

    Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications.

  13. Impacts of Soil Organic Stability on Carbon Storage in Coastal Wetlands

    Science.gov (United States)

    Williams, E. K.; Rosenheim, B. E.

    2015-12-01

    Coastal wetlands store vast amounts of organic carbon, globally, and are becoming increasingly vulnerable to the effects of anthropogenic sea level rise. Recently, we used ramped pyrolysis/oxidation decomposition characteristics as proxies for soil organic carbon (SOC) stability to understand the fate of carbon storage in coastal wetlands (fresh, brackish, and salt marshes) comprising the Mississippi River deltaic plain, undergoing rapid rates of local sea level rise. At equivalent soil depths, we observed that fresh marsh SOC was more thermochemically stable than brackish and salt marsh SOC. The differences in stability imply stronger carbon sequestration potential of fresh marsh soil carbon, compared to that of salt and brackish marshes. Here, we expand upon these results of differential organic carbon stability/reactivity and model how projected changes in salinity due to sea-level rise and other environmental changes will impact carbon storage in this region with implications globally.

  14. Mapping organic carbon stocks of Swiss forest soil

    Science.gov (United States)

    Nussbaum, M.; Papritz, A.; Baltensweiler, A.; Walthert, L.

    2012-04-01

    Carbon (C) sequestration into forest sinks offsets greenhouse gas emissions under the Kyoto protocol. Therefore, quantifying C stocks and fluxes in forest ecosystems is of interest for reporting greenhouse gas emissions. In Switzerland, the National Forest Inventory offers comprehensive data to quantify the above ground forest biomass and its change in time. Estimating stocks of soil organic C (SOC) in forests is more difficult because of its high spatial variability. To date the greenhouse gas inventory relies only on sparse data and regionally differentiated predictions of SOC stocks in forest soils are currently not possible. Recently, more soil data and new explanatory variables for statistical modeling like high resolution elevation data and satellite images became available. Based on data from 1'033 sites, we modeled SOC stocks to a depth of 1 m including the organic layer for the Swiss forested area. We used a novel robust restricted maximum likelihood method to fit a linear regression model with spatially correlated errors to the C stock data. For the regression analysis we used a broad range of covariates derived from climate data (precipitation, temperature, radiation), two elevation models (resolutions 25 and 2 m) and spectral variables representing vegetation. Furthermore, the main cartographic categories of an overview soil map were used to broadly represent the parent material. The numerous covariates, that partly correlated strongly, were reduced to a first subset using LASSO (Least Absolute Shrinkage and Selection Operator). This subset of covariates was then further reduced based on cross validation of the robustly fitted spatial model. The levels of categorical covariates were partly aggregated during this process and interactions between covariates were explored to account for nonlinear dependence of C stocks on the covariates. Using the final model, robust kriging prediction and error maps were computed with a resolution of one hectare.

  15. Soil erosion and organic carbon export by wet snow avalanches

    Directory of Open Access Journals (Sweden)

    O. Korup

    2014-01-01

    Full Text Available Many mountain belts sustain prolonged snow cover for parts of the year, although enquiries into rates of erosion in these landscapes have focused almost exclusively on the snow-free periods. This raises the question of whether annual snow cover contributes significantly to modulating rates of erosion in high-relief terrain. In this context, the sudden release of snow avalanches is a frequent and potentially relevant process, judging from the physical damage to subalpine forest ecosystems, and the amount of debris contained in avalanche deposits. To quantitatively constrain this visual impression and to expand the sparse existing literature, we sampled sediment concentrations of n = 28 river-spanning snow-avalanche deposits (snow bridges in the eastern Swiss Alps, and infer an orders-of-magnitude variability in specific fine sediment and organic carbon yields (1.8 to 830 t km−2 yr−1, and 0.04 to 131 t C km−2 yr−1, respectively. A Monte Carlo simulation demonstrates that, with a minimum of free parameters, such variability is inherent to the geometric scaling used for computing specific yields. Moreover, the widely applied method of linearly extrapolating plot-scale sample data may be prone to substantial under- or over-estimates. A comparison of our inferred yields with previously published work demonstrates the relevance of wet snow avalanches as prominent agents of soil erosion and transporters of biogeochemical constituents to mountain rivers. Given that a number of snow bridges persisted below the insulating debris cover well into the summer months, snow-avalanche deposits also contribute to regulating in-channel sediment and organic debris storage on seasonal timescales. Finally, our results underline the potential shortcomings of neglecting erosional processes in the winter and spring months in mountainous terrain subjected to prominent snow cover.

  16. Dutch (organic) agriculture, carbon sequestration and energy production

    NARCIS (Netherlands)

    Burgt, van der G.J.H.M.; Staps, S.; Timmermans, B.

    2010-01-01

    Carbon sequestration in soils is often mentioned in the discussions about climate changes. In this paper the opportunities for carbon sequestration in Dutch agriculture are discussed at farm and national level. Farm internal carbon sources are already completely used in livestock farming. The effect

  17. Sources of organic carbon in mangrove sediments: variability and possible ecological implications

    OpenAIRE

    Bouillon, Steven; Dahdouh-Guebas, F.; Rao, AVVS; N. Koedam; F. Dehairs

    2005-01-01

    Mangrove sediments from three different mangrove ecosystems (Coringa Wildlife Sanctuary in the Godavari Delta, Andhra Pradesh, India, and Galle and Pambala, south-west Sri Lanka) were analysed for their organic carbon content, elemental ratios (C:N) and carbon stable isotope composition. Organic carbon content (0.6 - 31.7% dry weight), C/N ratios (7.0 - 27.3) and delta(13)C (between -29.4 and -20.6parts per thousand) showed a wide range of values. Lower stocks of organic carbon coincided with...

  18. Utilization of spent activated carbon to enhance the combustion efficiency of organic sludge derived fuel.

    Science.gov (United States)

    Chen, Wei-Sheng; Lin, Chang-Wen; Chang, Fang-Chih; Lee, Wen-Jhy; Wu, Jhong-Lin

    2012-06-01

    This study examines the heating value and combustion efficiency of organic sludge derived fuel, spent activated carbon derived fuel, and derived fuel from a mixture of organic sludge and spent activated carbon. Spent activated carbon was sampled from an air pollution control device of an incinerator and characterized by XRD, XRF, TG/DTA, and SEM. The spent activated carbon was washed with deionized water and solvent (1N sulfuric acid) and then processed by the organic sludge derived fuel manufacturing process. After washing, the salt (chloride) and sulfide content could be reduced to 99% and 97%, respectively; in addition the carbon content and heating value were increased. Different ratios of spent activated carbon have been applied to the organic sludge derived fuel to reduce the NO(x) emission of the combustion.

  19. Emission of CO2 from biochar-amended soils and implications for soil organic carbon

    NARCIS (Netherlands)

    Sagrilo, E.; Jeffery, S.L.; Hoffland, E.; Kuyper, T.W.

    2015-01-01

    Soil amendment with pyrogenic organic matter (PyOM), also named biochar, is claimed to sequester carbon (C). However, possible interactions between PyOM and native soil organic carbon (SOC) may accelerate the loss of SOC, thus reducing PyOM's C sequestration potential. We combined the results of 46

  20. 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...

  1. The size distribution of organic carbon in headwater streams in the Amazon basin.

    Science.gov (United States)

    de Paula, Joana D'Arc; Luizão, Flávio Jesus; Piedade, Maria Teresa Fernandez

    2016-06-01

    Despite the strong representativeness of streams in the Amazon basin, their role in the accumulation of coarse particulate organic carbon (CPOC), fine particulate organic carbon (FPOC), and dissolved organic carbon (DOC) in transport, an important energy source in these environments, is poorly known. It is known that the arboreal vegetation in the Amazon basin is influenced by soil fertility and rainfall gradients, but would these gradients promote local differences in organic matter in headwater streams? To answer this question, 14 low-order streams were selected within these gradients along the Amazon basin, with extensions that varied between 4 and 8 km. The efficiency of the transformation of particulate into dissolved carbon fractions was assessed for each stream. The mean monthly benthic organic matter storage ranged between 1.58 and 9.40 t ha(-1) month(-1). In all locations, CPOC was the most abundant fraction in biomass, followed by FPOC and DOC. Rainfall and soil fertility influenced the distribution of the C fraction (p = 0.01), showing differentiated particulate organic carbon (POC) storage and DOC transportation along the basin. Furthermore, the results revealed that carbon quantification at the basin level could be underestimated, ultimately influencing the global carbon calculations for the region. This is especially due to the fact that the majority of studies consider only fine particulate organic matter and dissolved organic matter, which represent less than 50 % of the stored and transported carbon in streambeds.

  2. Using Pyrolysis Molecular Beam Mass Spectrometry to Characterize Soil Organic Carbon in Native Prairie Soils

    Science.gov (United States)

    The objective of this study was to characterize soil organic carbon (SOC) with pyrolysis molecular beam mass spectrometry (py-MBMS) and then to determine correlations between the mass spectra and associated soil characterization data. Both soil carbon chemistry and the organic forms in which SOC is...

  3. 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 colu

  4. Seasonal Distribution of Organic Carbon in the Surface Sediments of the Terengganu Nearshore Coastal Area

    Directory of Open Access Journals (Sweden)

    S. Hasrizal

    2009-01-01

    Full Text Available Problem statement: The distribution of organic carbon in the surface sediment is a crucial indicator for current productivity in the ocean especially in the nearshore area. The difference of organic carbon in the surface sediment reflects the influence of current movement on the bottom sediment. Approach: This study was carried out to oversee the difference of organic carbon distribution during pre and post-monsoon seasons. For the purpose of the study, 42 surface sediments in the Terengganu near shore area were collected and determined for organic carbon by using the wet dichromate acid method. Results: The concentration of organic carbon was significantly different between the seasons showing a relatively higher content during pre-monsoon seasons. In this study, the average concentration of organic carbon in pre-monsoon was 1.14±0.29% and varied from 0.60-1.80%. Meanwhile during post-monsoon seasons, the average concentration of organic carbon was slightly lower to 0.82±0.23% and ranged from 0.24-1.32%. Conclusion: Generally, the average concentration of organic carbon in South China Sea was low compared to the occurrence in riverine environment as well as the mangrove environment.

  5. Vertical distribution characteristics of soil organic carbon content in Caohai wetland ecosystem of Guizhou plateau, China

    Institute of Scientific and Technical Information of China (English)

    Yunjie Wu; Fengyou Wang; Sixi Zhu

    2016-01-01

    We selected four kinds of land use types from Caohai wetlands of Guizhou plateau (a total number of 32 soil profiles) to study the distribution characteristics of organic carbon content in soil. With different ways of land use, the organic carbon content of soil profiles and organic carbon density show the tendency of decreasing firstly and then increasing from top to bottom. With the increase of depth, the vertical difference becomes smaller first and then starts increasing. Land reclamation reduces the soil organic carbon content and density, changing its distribu-tion structure in topsoil. The average content of organic carbon in Caohai wetlands are as follows: lake bed silt [ marsh wetland [ farmland [ woodland, the average organic carbon content of lake bed silt, marsh wetland, farmland and woodland are 16.40, 2.94, 1.81 and 1.08%, respectively. Land reclamation reduces the organic carbon content of soil, therefore the conversion of cultivated lands to wetlands and the increase of forest coverage will help to fix the organic carbon in soil and increase its reserves.

  6. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures.

    Science.gov (United States)

    Fakher, Sundes; Nejm, Razan; Ayesh, Ahmad; Al-Ghaferi, Amal; Zeze, Dagou; Mabrook, Mohammed

    2016-01-01

    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. PMID:27598112

  7. 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.

  8. Development of strong and bioactive calcium phosphate cement as a light-cure organic-inorganic hybrid.

    Science.gov (United States)

    Barounian, M; Hesaraki, S; Kazemzadeh, A

    2012-07-01

    In this research, light cured calcium phosphate cements (LCCPCs) were developed by mixing a powder phase (P) consisting of tetracalcium phosphate and dicalcium phosphate and a photo-curable resin phase (L), mixture of hydroxyethylmethacrylate (HEMA)/poly acrylic-maleic acid at various P/L ratios of 2.0, 2.4 and 2.8 g/mL. Mechanical strength, phase composition, chemical groups and microstructure of the cured cements were evaluated at pre-set times, i.e. before and after soaking in simulated body fluid (SBF). The proliferation of Rat-derived osteoblastic cells onto the LCCPCs as well as cytotoxicity of cement extracts were determined by cell counting and 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyl-2H-tetrazolium bromide assay after different culture times. It was estimated from Fourier transforming infrared spectra of cured cements that the setting process is ruled by polymerization of HEMA monomers as well as formation of calcium poly-carboxylate salts. Microstructure of the cured cements consisted of calcium phosphate particles surrounded by polymerized resin phase. Formation of nano-sized needlelike calcium phosphate phase on surfaces of cements with P/L ratios of 2.4 and 2.8 g/mL was confirmed by scanning electron microscope images and X-ray diffractometry (XRD) of the cured specimen soaked in SBF for 21 days. Also, XRD patterns revealed that the formed calcium phosphate layer was apatite phase in a poor crystalline form. Biodegradation of the cements was confirmed by weight loss, change in molecular weight of polymer and morphology of the samples after different soaking periods. The maximum compressive strength of LCCPCs governed by resin polymerization and calcium polycarboxylate salts formation was about 80 MPa for cement with P/L ratio of 2.8 g/mL, after incubation for 24 h. The strength of all cements decreased by decreasing P/L ratio as well as increasing soaking time. The preliminary cell studies revealed that LCCPCs could support proliferation of

  9. Temperature Sensitivity of Soil Organic Carbon Mineralization along an Elevation Gradient in the Wuyi Mountains, China

    OpenAIRE

    Guobing Wang; Yan Zhou; Xia Xu; Honghua Ruan; Jiashe Wang

    2013-01-01

    Soil organic carbon (SOC) actively participates in the global carbon (C) cycle. Despite much research, however, our understanding of the temperature sensitivity of soil organic carbon (SOC) mineralization is still very limited. To investigate the responses of SOC mineralization to temperature, we sampled surface soils (0-10 cm) from evergreen broad-leaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM) along an elevational gradient in the Wuyi Mountai...

  10. ORGANIC CHELATING REAGENT ON REDOX ADSORPTION OF ACTIVATED CARBON FIBER TOWARDS Au3+

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Organic chelating reagent influences upon the redox adsorption of activated carbon fibertowards Au3- were systematically investigated. The experimental results indicated that the presenceof organic chelating reagent on activated carbon fiber strongly affects adsorption capacity ofactivated carbon fiber towards Au3+. The reduction-adsorption amount of Au3+ increased three timesby the presence of 8-quinolinol. Furthermore, The reduction-adsorption amount of Au3+ depended onthe pH value of adsorption and temperature.

  11. Terrain influence on soil organic carbon and total nitrogen sorage in soils of Herschel Island

    OpenAIRE

    Obu, Jaroslav; Lantuit, Hugues; Fritz, Michael; Myers-Smith, Isla; Heim, Birgit; Wolter, Juliane

    2015-01-01

    The Arctic-wide increase of permafrost temperatures and subsequent thaw is mobilising large amounts of organic matter that is stored in permafrost environments. Organic matter decomposition results in the release of carbon dioxide and methane, which will amplify the warming and will cause so called permafrost carbon feedback. Increasing air temperatures due to greenhouse gas emissions from permafrost is not yet incorporated into Earth System Models. The lack of high-resolution carbon storage ...

  12. Global pulses of organic carbon burial in deep-sea sediments during glacial maxima

    Science.gov (United States)

    Cartapanis, Olivier; Bianchi, Daniele; Jaccard, Samuel L.; Galbraith, Eric D.

    2016-02-01

    The burial of organic carbon in marine sediments removes carbon dioxide from the ocean-atmosphere pool, provides energy to the deep biosphere, and on geological timescales drives the oxygenation of the atmosphere. Here we quantify natural variations in the burial of organic carbon in deep-sea sediments over the last glacial cycle. Using a new data compilation of hundreds of sediment cores, we show that the accumulation rate of organic carbon in the deep sea was consistently higher (50%) during glacial maxima than during interglacials. The spatial pattern and temporal progression of the changes suggest that enhanced nutrient supply to parts of the surface ocean contributed to the glacial burial pulses, with likely additional contributions from more efficient transfer of organic matter to the deep sea and better preservation of organic matter due to reduced oxygen exposure. These results demonstrate a pronounced climate sensitivity for this global carbon cycle sink.

  13. Role of organic soils in the world carbon cycle: problem analysis and research needs

    Energy Technology Data Exchange (ETDEWEB)

    Armentano, T.V. (ed.)

    1980-02-01

    In May 1979, The Institute of Ecology held a workshop to determine the role of organic soils in the global carbon cycle and to ascertain their past, present and future significance in world carbon flux. Wetlands ecologists and soil scientists who participated in the workshop examined such topics as Soils as Sources of Atmospheric CO/sub 2/, Organic Soils, Primary Production and Growth of Wetlands Ecosystems, and Management of Peatlands. The major finding of the workshop is that the 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/.

  14. 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

    The following goals were addressed in the workshop: review and analysis of available data on carbon in organic soils from the past century to the present; assessment of the probable flux of carbon to and from organic soils in the near future; identification of major data inadequacies which preclude reliable analysis of the principal processes influencing carbon flux in organic soils; and proposal of research initiatives which could improve understanding of organic deposits in relation to the carbon cycle within a time frame of two to four years. The major finding of the workshop is that the 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. 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. Annual sequestering of carbon by undrained organic soils has been estimated at about 0.045 x 10/sup 9/ tons. Several strategies for peatland management are available, including creation, preservation, functional designation, and use of wetlands for agriculture and energy supply.

  15. Patterns and drivers of riverine particulate organic carbon transport in an Andean valley

    OpenAIRE

    Clark, Kathryn Elizabeth; Malhi, Yadvinder; New, Mark

    2014-01-01

    Physical erosion can mobilise particulate organic carbon (POC) from vegetation and soil, representing an export of primary productivity from ecosystems, and a lateral transfer of carbon recently-derived from the atmosphere. These carbon transfers are thought to be enhanced in mountain forests where erosion rates are high. However, the rates and controls on POC transfer remain poorly constrained, as does the impact of POC export on carbon cycling at regional and global scales. This thesis take...

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

    OpenAIRE

    Kabindra Adhikari; Hartemink, Alfred E.; Budiman Minasny; Rania Bou Kheir; Mette B Greve; Greve, Mogens H.

    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 soil depth intervals (0-5, 5-15, 15-30, 30-60 and 60-100 cm) using 18 environmental variables as predictors. SOC distribution was influenced by precipitation, land use, soil type, wetland, elevation, ...

  17. Dissolved inorganic carbon and organic carbon in mires in the Forsmark area. A pilot study

    International Nuclear Information System (INIS)

    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 Ca2+ 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

  18. 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.

  19. 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

  20. Aerosol organic carbon to black carbon ratios: Analysis ofpublished data and implications for climate forcing

    Energy Technology Data Exchange (ETDEWEB)

    Novakov, T.; Menon, S.; Kirchstetter, T.W.; Koch, D.; Hansen, J.E.

    2005-07-11

    Measurements of organic carbon (OC) and black carbon (BC)concentrations over a variety of locations worldwide, have been analyzed to infer the spatial distributions of the ratios of OC to BC. Since these ratios determine the relative amounts of scattering and absorption, they are often used to estimate the radiative forcing due to aerosols. An artifact in the protocol for filter measurements of OC has led to widespread overestimates of the ratio of OC to BC in atmospheric aerosols. We developed a criterion to correct for this artifact and analyze corrected OC to BC ratios. The OC to BC ratios, ranging from 1.3to 2.4, appear relatively constant and are generally unaffected by seasonality, sources or technology changes, at the locations considered here. The ratios compare well with emission inventories over Europe and China but are a factor of two lower in other regions. The reduced estimate for OC/BC in aerosols strengthens the argument that reduction of soot emissions maybe a useful approach to slow global warming.

  1. Improved biocompatibility of novel poly(L-lactic acid/ß-tricalcium phosphate scaffolds prepared by an organic solvent-free method

    Directory of Open Access Journals (Sweden)

    Zhao XF

    2011-07-01

    Full Text Available Xue-Feng Zhao1,2, Xiao-Dong Li3, Yun-Qing Kang4, Quan Yuan1,21State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, People's Republic of China; 2West China School of Stomatology, Sichuan University, Chengdu, People's Republic of China; 3Affiliated Hospital of Stomatology and College of Stomatology, Chongqing Medical University, Chongqing, People's Republic of China; 4College of Materials Science and Engineering, Sichuan University, Chengdu, People's Republic of ChinaAbstract: A porous poly(L-lactic acid/ß-tricalcium phosphate (PLLA/ß-TCP composite scaffold was fabricated using a novel technique comprising powder mixing, compression molding, low-temperature treatment, and particulate leaching without any organic solvent. The effect of this scaffold on osteoblast proliferation and differentiation was evaluated in vitro. The fabricated scaffold had a homogeneously interconnected porous structure with a porosity of 70% and compressive strength of 1.35 MPa. The methylthiazol tetrazolium values and alkaline phosphatase (ALP activity of osteoblasts seeded on the solvent-free scaffold were significant higher than those of the control. Using real-time PCR, gene expressions of ALP, osteocalcin, and type 1 collagen were shown to be upregulated. As the method does not use any organic solvent, it eliminates problems associated with organic solvent residue and therefore improves the cell compatibility. It has a promising potential for the preparation of porous scaffold for bone tissue engineering.Keywords: biocompatibility, biomaterials, composites, poly(L-lactic acid, ß-tricalcium phosphate

  2. Second Hydrocarbon—Generation from Organic Matter Trapped in Fluid Inclusions in Carbonate Rocks

    Institute of Scientific and Technical Information of China (English)

    施继锡; 余孝颖

    1999-01-01

    The mechanism and significance of second hydrocarbon-generation from organic matter trapped in fluid inclusions in carbonate rocks are discussed.The types of organic matter and the relationship between them are also reviewed.The organic matter trapped in inclusions and crystals,which account for more than 20%of the total organic matter in carbonate rocks,may be of great significance in the generation of hydrocarbons.High-temperature oil resulting from second hydrocarbon-generation should be an important target,in addition to natural gas,in oilgas prospecting in regions of high-maturity carbonate rocks.

  3. Processes controlling production and transport of dissolved organic carbon in forest soils

    OpenAIRE

    Fröberg, Mats

    2004-01-01

    Dissolved organic carbon (DOC) leached from the O horizon of forest soils is a major source of soil organic carbon in the mineral soil, where a major proportion of the organic carbon in forest ecosystems is located. The relative contribution of recent litter and humified organic matter to the leaching of DOC from the O horizon is still being debated. In the present work, I studied the sources of DOC leached from the O horizon by manipulating the amounts of litter and humus and measuring DOC c...

  4. Lunar carbon chemistry - Relations to and implications for terrestrial organic geochemistry.

    Science.gov (United States)

    Eglinton, G.; Maxwell, J. R.; Pillinger, C. T.

    1972-01-01

    Survey of the various ways in which studies of lunar carbon chemistry have beneficially affected terrestrial organic geochemistry. A lunar organic gas-analysis operating system is cited as the most important instrumental development in relation to terrestrial organic geochemistry. Improved methods of analysis and handling of organic samples are cited as another benefit derived from studies of lunar carbon chemistry. The problem of controlling contamination and minimizing organic vapors is considered, as well as the possibility of analyzing terrestrial samples by the techniques developed for lunar samples. A need for new methods of analyzing carbonaceous material which is insoluble in organic solvents is indicated.

  5. 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.

  6. Plastidial Glycolytic Glyceraldehyde-3-Phosphate Dehydrogenase Is an Important Determinant in the Carbon and Nitrogen Metabolism of Heterotrophic Cells in Arabidopsis.

    Science.gov (United States)

    Anoman, Armand D; Muñoz-Bertomeu, Jesús; Rosa-Téllez, Sara; Flores-Tornero, María; Serrano, Ramón; Bueso, Eduardo; Fernie, Alisdair R; Segura, Juan; Ros, Roc

    2015-11-01

    This study functionally characterizes the Arabidopsis (Arabidopsis thaliana) plastidial glycolytic isoforms of glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in photosynthetic and heterotrophic cells. We expressed the enzyme in gapcp double mutants (gapcp1gapcp2) under the control of photosynthetic (Rubisco small subunit RBCS2B [RBCS]) or heterotrophic (phosphate transporter PHT1.2 [PHT]) cell-specific promoters. Expression of GAPCp1 under the control of RBCS in gapcp1gapcp2 had no significant effect on the metabolite profile or growth in the aerial part (AP). GAPCp1 expression under the control of the PHT promoter clearly affected Arabidopsis development by increasing the number of lateral roots and having a major effect on AP growth and metabolite profile. Our results indicate that GAPCp1 is not functionally important in photosynthetic cells but plays a fundamental role in roots and in heterotrophic cells of the AP. Specifically, GAPCp activity may be required in root meristems and the root cap for normal primary root growth. Transcriptomic and metabolomic analyses indicate that the lack of GAPCp activity affects nitrogen and carbon metabolism as well as mineral nutrition and that glycerate and glutamine are the main metabolites responding to GAPCp activity. Thus, GAPCp could be an important metabolic connector of glycolysis with other pathways, such as the phosphorylated pathway of serine biosynthesis, the ammonium assimilation pathway, or the metabolism of γ-aminobutyrate, which in turn affect plant development. PMID:26134167

  7. 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.

  8. Simulation of soil organic carbon in different soil size fractions using 13Carbon measurement data

    Science.gov (United States)

    Gottschalk, P.; Bellarby, J.; Chenu, C.; Foereid, B.; Wattenbach, M.; Zingore, S.; Smith, J.

    2009-04-01

    We simulate the soil organic carbon (SOC) dynamics at a chronoseqeunce site in France, using the Rothamsted Carbon model. The site exhibits a transition from C3 plants, dominated by pine forest, to a conventional C4 maize rotation. The different 13C signatures of the forest plants and maize are used to distinguish between the woodland derived carbon (C) and the maize derived C. The model is evaluated against total SOC and C derived from forest and maize, respectively. The SOC dynamics of the five SOC pools of the model, decomposable plant material (DPM), resistant plant material (RPM), biomass, humus and inert C, are also compared to the SOC dynamics measured in different soil size fractions. These fractions are > 50 μm (particulate organic matter), 2-50 μm (silt associated SOC) and 50 μm and the sum of the other pools corresponds well to the SOC measured in the soil size fraction stocks in the first 20 years after land-use change and overestimates the C accumulation of maize C. Several hypotheses were tested to evaluate the simulations. Input data and internal model parameter uncertainties had minor effects on the simulations results. Accounting for erosion and implementing a simple tillage routine did not improve the simulation fit to the data. We therefore hypothesize that a generic process that is not yet explicitly accounted for in the ROTHC model could explain the loss in soil C after land use change. Such a process could be the loss of the physical protection of soil organic matter as would be observed following cultivation of a previously uncultivated soil. Under native conditions a fraction of organic matter is protected in stable soil aggregates. These aggregates are physically disrupted by continuous and repeated cultivation of the soil. The underestimation of SOC loss by the model can be mainly attributed to the slow turnover of the humus pool. This pool was shown to represent mainly the SOC associated with the silt and clay soil fraction. Here, the

  9. 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).

  10. 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.

  11. 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

    2016-05-01

    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. PMID:27052495

  12. 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

  13. Decoupling of carbon isotope records between organic matter and carbonate prior to the Toarcian Oceanic Anoxic Event (Early Jurassic)

    Science.gov (United States)

    Bodin, Stephane; Kothe, Tim; Krencker, Francois-Nicolas; Suan, Guillaume; Heimhofer, Ulrich; Immenhauser, Adrian

    2014-05-01

    Across the Pliensbachian-Toarcian boundary (P-To, Early Jurassic), ca. 1 Myr before the Toarcian Oceanic Anoxic Event (T-OAE), an initial negative carbon isotope excursion has been documented in western Tethys sedimentary rocks. In carbonate, its amplitude (2-3 permil) is similar to the subsequent excursion recorded at the onset of the T-OAE. Being also associated with a rapid warming event, the significance of this first carbon isotope shift, in terms of paleoenvironmental interpretation and triggering mechanism, remains however elusive. Taking advantage of expanded and rather continuous sections in the High Atlas of Morocco, several high-resolution, paired organic-inorganic carbon isotope records have been obtained across the Upper Pliensbachian - Lower Toarcian interval. At the onset of the T-OAE, an abrupt 1-2 permil negative shift is recorded in both organic and inorganic phases, succeeded by a relatively longer term 1-2 permil negative trend and a final slow return to pre-excursion conditions. In accordance with previous interpretations, this pattern indicates a perturbation of the entire exogenic carbon isotope reservoir at the onset of the T-OAE by the sudden release of isotopically light carbon into the atmosphere. By contrast, there is no negative shift in carbon isotopes for the P-To event recorded in bulk organic matter of Morocco. Given the strong dominance of terrestrial particles in the bulk organic matter fraction, this absence indicates that massive input of 12C-rich carbon into the atmosphere is not likely to have happened during the P-To event. A pronounced (2 permil) and abrupt negative shift in carbon isotope is however recorded in the bulk carbonate phase. We suggest that this decoupling between organic and inorganic phase is due to changes in the nature of the bulk carbonate phase. Indeed, the negative shift occurs at the lithological transition between Pliensbachian-lowermost Toarcian limestone-marl alternations and the Lower Toarcian marl

  14. Soil organic carbon forms with different uses in the department of magdalena (colombia)

    OpenAIRE

    Vásquez Polo, José Rafael; Macías Vázquez, Felipe; Menjivar Flores, Juan Carlos

    2012-01-01

    Fractions of soil organic matter (SOM) labile and humified, can be affected by use and management practices, but the impact of these changes has not been evaluated in soils of tropical environments. The present study investigated the contents and some forms of soil organic carbon (SOC) in five warm tropical climate zones of the Department of Magdalena (Colombia), and the effect of the cropping practices on these forms of organic carbon in cultivated soils, associated with Coffee (Coffea arabi...

  15. Tracing organic matter sources and carbon burial in mangrove sediments over the past 160 years

    Science.gov (United States)

    Gonneea, Meagan Eagle; Paytan, Adina; Herrera-Silveira, Jorge A.

    2004-10-01

    Mangrove ecosystems may be a source of organic carbon and nutrients to adjacent coastal systems on one hand and provide a sedimentary sink for organic carbon on the other. The balance between these two functions may be sensitive to both natural and anthropogenically induced variability, yet these effects have not been thoroughly evaluated in mangrove ecosystems. We determine organic matter sources and carbon burial rates over the past 160 years in three lagoons on the Yucatan Peninsula, Mexico. Carbon isotopes and C/N elemental ratios are utilized to trace the three sources contributing to sedimentary organic matter, mangroves, seagrasses and phytoplankton, while nitrogen isotopes are used to elucidate potential post-depositional biogeochemical transformations in mangrove lagoon sediments. All three organic matter sources contribute to organic carbon burial. Phytoplankton and mangroves are the dominant sources of organic matter in lagoon bank sediments and seagrasses are a significant source to central lagoon sediments. Organic carbon burial rates are higher at the lagoon fringes, where mangrove vegetation dominates, than in seagrass-dominated mid-lagoon areas. A reduction in mangrove contribution to the sedimentary organic matter pool concurrent with reduced total organic carbon burial rates is observed in the recent past at all three lagoons studied. Natural cycles in sediment organic matter source over the past 160 years are observed in a high-resolution core. These fluctuations correspond to climatic variability in this region, as recorded in deep-sea foraminiferal assemblages. Additional work is required in order to differentiate between recent anthropogenic perturbations and natural variability in organic carbon sources and burial rates within these ecosystems.

  16. The energetic and chemical fingerprints of persistent soil organic carbon

    Science.gov (United States)

    Barré, Pierre; Plante, Alain F.; Cécillon, Lauric; Lutfalla, Suzanne; Baudin, François; Bernard, Sylvain; Christensen, Bent T.; Fernandez, Jose M.; Houot, Sabine; Kätterer, Thomas; Macdonald, Andy; van Oort, Folkert; Le Guillou, Corentin; Chenu, Claire

    2016-04-01

    A better understanding of soil organic carbon (SOC) persistence is needed to better predict SOC vulnerability to global change. The absence of convincing physical or chemical procedures to define, characterize or isolate relatively labile versus persistent SOC pools makes the study of persistent SOC difficult. Long-term bare fallow (LTBF) experiments, in which C inputs have been stopped for several decades, provide a unique opportunity to study persistent SOC without the inherent artefacts induced by extraction procedures, the hypothesis being that SOC is gradually enriched in persistent C with time as labile components decompose. We determined the evolution of thermal and chemical characteristics of bulk SOC in five LTBF experiments across Europe: Askov (DK), Grignon (FR), Rothamsted (UK), Ultuna (SW) and Versailles (FR), using a multi-technique approach involving Rock-Eval pyrolysis, thermogravimetry and differential scanning calorimetry (TG-DSC), mid-infrared diffuse reflectance spectroscopy (DRIFT-MIRS), and Near Edge X-Ray Absorption Fine Structure (NEXAFS). Results of Rock-Eval and TG analyses showed that the temperature needed to combust the SOC increased with bare fallow duration at all sites. Conversely, SOC energy density (in mJ mg-1 C) measured by DSC decreased with bare fallow duration. Rock-Eval pyrolysis results showed that hydrogen index (HI) tended to decrease with bare fallow duration whereas the oxygen index (OI) did not show consistent trends across sites. NEXAFS signals presented little differences and were dominated by carboxyl peak. Nonetheless, NEXAFS results showed a trend of increasing carboxyl groups and decreasing ketone and amide groups with bare fallow duration. Due to the mineral matrix, only a reduced part of the DRIFT-MIRS signals has been used. We observed that the bulk chemistry of aliphatic SOC (CH3 vs. CH2 functional groups) showed different trends for the different sites. Our results showed that in spite of the heterogeneity of

  17. Hyperspectral remote sensing for soil organic carbon mapping

    Science.gov (United States)

    Stevens, A.; van Wesemael, B.

    2009-04-01

    Satellite and airborne hyperspectral remote sensing is increasingly investigated as a fast and convenient tool to map soil properties. However, several research have pointed out the difficulty to obtain good calibration results over large areas due to spatial variation in soil types and surface soil conditions (moisture content, roughness, vegetation cover). These effects induce a spectral variability not directly related to the property studied and decrease the accuracy of predictions. A flight campaign was organized on 4-9th October 2007 using the AHS-160 airborne spectrometer to predict Soil Organic Carbon (SOC) in bare cropland soils in Grand-Duchy of Luxembourg. The study area consisted in a north-south transect of ~7 km width and ~60 km length and crossed 4 of the 5 agro-geological regions of Luxembourg, characterized by various soil types such as Cambisols, Luvisols, Arenosols and Calcisols. After collecting more than 300 soil samples of the soil surface, spectral data was related with SOC content using several standard multivariate calibration techniques (Partial Least Square Regression, Penalized-spline Regression, Support Vector Machine). It is shown that calibrations yield reasonably accurate predictions over large areas as long as secondary information (e.g. soil types, agro-pedological regions) are included in the models (Root Mean Square Error of Prediction: ~3 g C kg-1). Such calibration models could be applied to every soil pixel of the hyperspectral image to produce a SOC map of the area. However, predictions have been realized using statistical relationships based on a set of calibration randomly chosen from a set of samples collected during a field campaign, the rest being used for validation purposes. It means that the validation set is not completely independent from the calibration set. As a consequence, a true independent validation (over fields not covered by the calibration/validation sets) would probably give lower accuracies than the ones

  18. Soil organic carbon, macropore networks and preferential transport

    Science.gov (United States)

    Larsbo, Mats; Koestel, John; Kätterer, Thomas; Jarvis, Nick

    2016-04-01

    Agricultural management practices such as tillage, crop rotations, residue management and fertilization can have a strong influence on soil organic carbon (SOC) stocks. An increase in SOC content will generally improve soil structure, which in turn determines the solute transport pathways through the soil. The aim of this study was to quantify the architecture of macropore networks in undisturbed soil columns (15 cm high, 12.7 cm diameter) sampled along a transect with natural variations in SOC using X-ray tomography and to relate the network characteristics to the degree of preferential transport in the columns. Two tracer experiments were carried out at constant irrigation rates of 2 and 5 mm h-1. We used the normalised 5% arrival time which reflects the tendency for early arrival of the solutes as a measure of the degree of preferential transport. The soil macropore networks were analysed in cylindrical sub-volumes (8 cm high, 10 cm diameter) located centrally within the soil columns. These sub-volumes were considered unaffected by sampling artefacts. Analyses were also carried out the for whole sample volumes to enable comparisons with the results from the transport experiments. Image processing and analysis were carried out in ImageJ and R. The same grey value threshold was applied to all images after harmonisation of grey values using the PVC column walls and the air outside the columns. This approach resulted in a satisfactory separation between the pore space and the surrounding soil matrix and organic matter. The SOC content along the transect, which varied from 4.2 to 15% , was correlated to all measures of the pore network for the sub-volumes except for the connectivity probability. Columns with high SOC content were associated with large macroporosities (both total and connected), large specific surface areas, large fractal dimensions and small mean pore thicknesses. The SOC content for whole sample volumes was positively correlated to 5% arrival times

  19. 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

  20. Organic Carbon Influences on Soil Particle Density and Rheological Properties

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Canqui, H; Lal, Rattan; Post, W M.; Izaurralde, R Cesar C.; Shipitalo, M. J.

    2006-07-01

    Soil particle density (rs) is not routinely measured and is assumed to range between 2.60 and 2.70 Mgm23 or to be a constant (2.65 Mgm23) when estimating essential properties such as porosity, and volumetric water and air relations. Values of rs for the same soil may, however, differ significantly from the standard range due to management induced changes in soil organic carbon (SOC) concentrations. We quantified the rs and Atterberg limits of a Rayne silt loam for five long-term (.22 yr) moldboard-plowed continuous corn (Zea mays L.; MP), no-till continuous corn (NT), no-till continuous corn with beef cattle manure (NTm), pasture, and forest systems.We also assessed the relationships of SOC concentration with rs and the Atterberg limits and the impact of rs on soil porosity. Mean rs across NT, NTm, and pasture (2.35 Mg m23) was |7% lower than that for MP in the 0- to 10-cm soil depth (2.52 Mg m23, P , 0.01). Forest had the lowest rs of all soils (1.79 Mg m23). The NTm caused a greater reduction in rs and a greater increase in SOC concentration, liquid limit (LL), plastic limit (PL), and plasticity index (PI) than NT. Surface soils under MP had the highest rs and rb and the lowest SOC concentration, LL, PL, and PI. The SOC concentration was correlated negatively with rs (r 2 5 0.75) and positively with Atterberg limits (r 2 . 0.64) at .20-cm depth. Estimates of soil porosity for NT, NTm, and pasture using the constant rs overestimated the ''true'' porosity by 12% relative to that using the measured rs.

  1. 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.

  2. Carbon isotopic studies of individual lipids in organisms from the Nansha sea area, China

    Institute of Scientific and Technical Information of China (English)

    DUAN Yi; SONG Jinming; ZHANG Hui

    2004-01-01

    Carbon isotopes of individual lipids in typical organisms from the Nansha sea area were measured by the GC-IRMS analytical technique. δ13C values of saturated fatty acids in different organisms examined are from -25.6‰ to -29.7‰ with the average values ranging from -26.4‰ to -28.2‰ and the variance range of 1.8‰ between different organisms is also observed.Unsaturated fatty acids have heavy carbon isotopic compositions and the mean differences of 2.9‰-6.8‰ compared to the same carbon number saturated fatty acids. δ13C values of n-alkanes range from -27.5‰ to -29.7‰ and their mean values, ranging from -28.6‰ to -28.9‰, are very close in different organisms. The mean difference in δ13C between the saturated fatty acids and n-alkanes is only 1.5‰, indicating that they have similar biosynthetic pathways. The carbon isotopic variations between the different carbon-number lipids are mostly within ±2.0‰, reflecting that they experienced a biosynthetic process of the carbon chain elongation. At the same time, the carbon isotopic genetic relationships between the biological and sedimentary lipids are established by comparative studies of carbon isotopic compositions of individual lipids in organisms and sediments from the Nansha sea area, which provides scientific basis for carbon isotopic applied research of individual lipids.

  3. 新型有机结合态磷肥田间试验效果%Field Experimental Results of New-Type Organic Combined State Phosphatic Fertilizers

    Institute of Scientific and Technical Information of China (English)

    韩霜; 李菊梅; 戴建军

    2012-01-01

    Corn is planted in the dry red earth land, and normal superphosphate is used as a contrast, making a comparison of new-type organic combined state phosphatic fertilizers: starch phosphatic fertilizer and straw phosphatic fertilizer with respect to their fertilizer efficiency. The results show that these two new-type fertilizers are better than normal superphosphate in increase in soil readily available phosphate content, corn yield and fertilizer availability. With the application of 60 kg/hm" of each, the readily available phosphate content in the soil is higher than that of the superphosphate by 57.4% and 59. 1% , respectively. With the application of 90 kg/hm of each, the available phosphate content is higher by 63.0% and 93.3%, respectively. With the application of 60 kg/hm2 of each, the corn yield is higher by 2. 6% and 15. 2% respectively than that when 90 kg/hm2 of superphosphate is used. In the case of high yield, the application of organic combined state phosphatic fertilizers may be lowered by one-third than superphosphate, and the fertilizer availability rises by 29. 5% on the average.%红壤旱地种植玉米,以普通过磷酸钙作对比,比较了新型有机结合态磷肥——淀粉磷肥和秸秆磷肥的肥料效果.结果表明:2种新型磷肥在提高土壤速效磷含量及玉米产量和肥料利用率方面都优于普通过磷酸钙;分别施用淀粉磷肥和秸秆磷肥60kg/hm2,土壤速效磷含量比普通过磷酸钙提高了57.4%和59 1%;分别施用90 kg/hm2时,土壤速效磷含量分别比普通过磷酸钙提高了63.0%和93.3%;施用2种新型磷肥60 kg/hm2,玉米产量优于施用普通过磷酸钙90 kg/hm2的效果,产量分别提高了2.6%和15.2%;在达到高产的情况下,有机结合态磷肥可以比普通过磷酸钙使用量减少1/3,肥料利用率平均提高29 5%.

  4. Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds

    Science.gov (United States)

    Kronholm, Scott; Capel, Paul

    2012-01-01

    Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1–6.8) and 1.1 (range: 0.4–3.8) mg C L−1, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha−1 yr−1. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO2 emissions.

  5. 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.

  6. Flocculation of Allochthonous Dissolved Organic Matter – a Significant Pathway of Sedimentation and Carbon Burial in Lakes

    OpenAIRE

    von Wachenfeldt, Eddie

    2008-01-01

    Inland waters receive substantial amounts of organic carbon from adjacent watersheds. Only about half of the carbon exported from inland waters reaches the oceans, while the remainder is lost en route. This thesis identifies flocculation as an important and significant fate of carbon in the boreal landscape. Flocculation reallocates organic carbon from the dissolved state into particles which are prone to settle. Thus, flocculation relocates organic carbon from the water column to the sedimen...

  7. Research on determining organic carbon in rock and mineral samples by gas chromatography

    International Nuclear Information System (INIS)

    The authors introduce results of research on transformation mechanism, temperature and time of organic carbon during analysis of rock and mineral samples by gas chromatography, as well as conditions for eliminating carbonate constituent that may produce carbon dioxide gas. The research has solved the problem of connecting the chemical processing and instrument determination. The newly-established method is characterized by high sensitivity, good exactitude, simple and fast operation, and may be applied to the determination of organic carbon in rock, mineral, as well as sediment samples

  8. Bismuth oxychloride modified titanium phosphate nanoplates: A new p-n type heterostructured photocatalyst with high activity for the degradation of different kinds of organic pollutants.

    Science.gov (United States)

    Ao, Yanhui; Bao, Jiaqiu; Wang, Peifang; Wang, Chao; Hou, Jun

    2016-08-15

    In this work, BiOCl modified titanium phosphate nanoplates (BiOCl/TP) composite photocatalysts with p-n heterojunctions were prepared by a in-situ growth method. The morphology, crystal structure and optical properties of the prepared samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectrometry (DRS). Rhodamine B (RhB), reactive brilliant Red X-3B (X-3B), methylene blue (MB), ciprofloxacin (CIP) and phenol were used to investigate the photocatalytic performance of the prepared samples under ultraviolet light irradiation. Results showed that the BiOCl/TP exhibited much higher activity for the degradation of all these model organic pollutants than pure TP. The mechanism for the enhancement of the photocatalytic performance was established with the help of the results of photocurrent measurements and Photoluminescence spectra. The results illustrated that the enhanced activity could be attributed to the formation of p-n heterojunctions between p-type BiOCl and n-type titanium phosphate, which effectively suppressed the recombination of photo-induced electron-hole pairs. Furthermore, the possible photocatalytic mechanisms on the degradation of the organic pollutants were also proposed. PMID:27209392

  9. Effects of organic amendments on soil carbon sequestration in paddy fields of subtropical China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenju; Xu, Minggang [Chinese Academy of Agricultural Sciences, Beijing (China). Ministry of Agriculture Key Lab. of Crop Nutrition and Fertilization; Wang, Xiujun [Chinese Academy of Sciences, Urumqi (China). Xinjiang Inst. of Ecology and Geography; Maryland Univ., College Park, MD (United States). Earth System Science Interdisciplinary Centre; Huang, Qinhai [National Engineering and Technology Research Center for Red Soil Improvement, Jinxian (China). Jiangxi Inst. of Red Soils; Nie, Jun [Soil and Fertilizer Institute of Hunan Province, Changsha (China); Li, Zuzhang [Jiangxi Academy of Agricultural Sciences, Nanchang (China). Inst. of Soils and Fertilizers and Agricultural Resources; Li, Shuanglai [Hubei Academy of Agricultural Sciences, Wuhan (China). Inst. of Plant Protection and Soil Science; Hwang, Seon Woong; Lee, Kyeong Bo [National Institute of Crop Sciences, Iksan (Korea, Republic of). Dept. of Rice and Winter Cereal Crop

    2012-04-15

    Purpose: Although organic amendments have been recommended as one of the practices for crop production and soil carbon sequestration, little has been done to evaluate soil organic carbon (SOC) dynamics following long-term application of organic amendments. The objective of this research were to (1) assess the effect of long-term organic amendments on SOC dynamics in rice-based systems; (2) evaluate the relationship between soil carbon sequestration and carbon input based on various mineral and organic fertilization treatments. Materials and methods: A multi-sites analysis was conducted on four long-term experiments with double-rice (three sites) and rice-wheat (one site) cropping systems which started in the 1980s in Southern China. We selected three groups of treatments in common at each site: (1) control (no fertilizer), (2) mineral nitrogen-phosphorus with and without potassium (NPK/NP), and (3) the combined treatments of mineral NP/NPK with pig manure (M), green manure (G, Astragalus sinicus L.), rice straw (S), and/or their combinations. Harvestable crop biomass was annually recorded for all plots. SOC in topsoil was determined in 1-5 yearly intervals after rice harvest. Results and discussion: Analysis showed that organic amendments sustained or significantly increased carbon biomass, but had little effects on the coefficient of variance (CV) of the carbon biomass production compared with the mineral NPK/NP treatments. With additional carbon input, organic amendments increased SOC significantly by 7-45% after 25-28 years of fertilization compared with the mineral treatments. These combined treatments sequestered carbon at a rate from 0.20 to 0.48 tha{sup -1} year{sup -1} under the double-rice and 0.70 to 0.88 t ha{sup -1} year{sup -1} under rice-wheat cropping system. The estimated annual SOC decomposition rate ranged from 0.15 to 0.82 tha{sup -1} at these studied sites. Our analyses revealed strong positive correlations between soil carbon sequestration and

  10. Dysregulation of phosphate metabolism and conditions associated with phosphate toxicity.

    Science.gov (United States)

    Brown, Ronald B; Razzaque, Mohammed S

    2015-01-01

    Phosphate homeostasis is coordinated and regulated by complex cross-organ talk through delicate hormonal networks. Parathyroid hormone (PTH), secreted in response to low serum calcium, has an important role in maintaining phosphate homeostasis by influencing renal synthesis of 1,25-dihydroxyvitamin D, thereby increasing intestinal phosphate absorption. Moreover, PTH can increase phosphate efflux from bone and contribute to renal phosphate homeostasis through phosphaturic effects. In addition, PTH can induce skeletal synthesis of another potent phosphaturic hormone, fibroblast growth factor 23 (FGF23), which is able to inhibit renal tubular phosphate reabsorption, thereby increasing urinary phosphate excretion. FGF23 can also fine-tune vitamin D homeostasis by suppressing renal expression of 1-alpha hydroxylase (1α(OH)ase). This review briefly discusses how FGF23, by forming a bone-kidney axis, regulates phosphate homeostasis, and how its dysregulation can lead to phosphate toxicity that induces widespread tissue injury. We also provide evidence to explain how phosphate toxicity related to dietary phosphorus overload may facilitate incidence of noncommunicable diseases including kidney disease, cardiovascular disease, cancers and skeletal disorders. PMID:26131357

  11. 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...

  12. Changes in Organic Carbon Index of Grey Desert Soil in Northwest China After Long-Term Fertilization

    Institute of Scientific and Technical Information of China (English)

    XU Yong-mei; LIU Hua; WANG Xi-he; XU Ming-gang; ZHANG Wen-ju; JIANG Gui-ying

    2014-01-01

    Soil organic carbon (SOC), soil microbial biomass carbon (SMBC) and SMBC quotient (SMBC/SOC, qSMBC) are key indexes of soil biological fertility because of the relationship to soil nutrition supply capacity. Yet it remains unknown how these three indexes change, which limits our understanding about how soil respond to different fertilization practices. Based on a 22-yr (1990-2011) long-term fertilization experiment in northwest China, we investigated the dynamics of SMBC and qSMBC during the growing period of winter wheat, the relationships between the SMBC, qSMBC, soil organic carbon (SOC) concentrations, the carbon input and grain yield of wheat as well. Fertilization treatments were 1) nonfertilization (control);2) chemical nitrogen plus phosphate plus potassium (NPK);3) NPK plus animal manure (NPKM);4) double NPKM (hNPKM) and 5) NPK plus straw (NPKS). Results showed that the SMBC and qSMBC were signiifcantly different among returning, jointing, lfowering and harvest stages of wheat under long-term fertilization. And the largest values were observed in the lfowering stage. Values for SMBC and qSMBC ranged from 37.5 to 106.0 mg kg-1 and 0.41 to 0.61%, respectively. The mean value rank of SMBC during the whole growing period of wheat was hNPKM>NPKM>NPKS>CK>NPK. But there were no statistically signiifcant differences between hNPKM and NPKM, or between CK and NPK. The order for qSMBC was NPKS>NPKM>CK>hNPKM>NPK. These results indicated that NPKS signiifcantly increased the ratio of SMBC to SOC, i.e., qSMBC, compared with NPK fertilizer or other two NPKM fertilizations. Signiifcant linear relationships were observed between the annual carbon input and SOC (P<0.01) or SMBC (P<0.05), and between the relative grain yield of wheat and the SOC content as well (P<0.05). But the qSMBC was not correlated with the annual carbon input. It is thus obvious that the combination of manure, straw with mineral fertilizer may be beneift to increase SOC and improve soil quality than

  13. Distribution of Organic Carbon in the Sediments of Xinxue River and the Xinxue River Constructed Wetland, China.

    Directory of Open Access Journals (Sweden)

    Qingqing Cao

    Full Text Available 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.

  14. 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.

  15. Dissolved organic carbon reduces the toxicity of aluminum to three tropical freshwater organisms.

    Science.gov (United States)

    Trenfield, Melanie A; Markich, Scott J; Ng, Jack C; Noller, Barry; van Dam, Rick A

    2012-02-01

    The influence of dissolved organic carbon (DOC) on the toxicity of aluminum (Al) at pH 5 (relevant to acid mine drainage conditions), to the tropical green hydra (Hydra viridissima), green alga (Chlorella sp.), and cladoceran (Moinodaphnia macleayi) was assessed. Two DOC sources, a natural in situ DOC in soft billabong water (SBW) and Suwannee River fulvic acid (SRFA) standard, were compared. The order of sensitivity of the test organisms to dissolved Al (0.1 µm fraction) was Hydra viridissima > Moinodaphnia macleayi > Chlorella sp. with DOC reducing dissolved Al toxicity most for Hydra viridissima. However, colloidal or precipitated Al may contribute indirectly to the toxicity for M. macleayi and Chlorella sp. The toxicity of dissolved Al was up to six times lower in test waters containing 10 mg L(-1) DOC (in the form of SRFA), relative to toxicity observed at 1 mg L(-1) DOC. In contrast, the toxicity of Al was up to two times lower in SBW containing 10 mg L(-1) DOC, relative to water containing 1 mg L(-1) DOC. The increased ability of SRFA in reducing Al toxicity was linked to its greater affinity for complexing Al compared with the in situ DOC. This has important implications for studies that use commercial standards of humic substances to predict Al toxicity in local environments. Speciation modeling demonstrated that Al(3+) and AlOH(2+) provided a strong relationship with toxicity. An empirical relationship is provided for each organism that can be used to predict Al toxicity at a given Al and DOC concentration. PMID:22105345

  16. 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.

  17. Dynamics of Soil Organic Carbon and Microbial Biomass Carbon in Relation to Water Erosion and Tillage Erosion

    OpenAIRE

    Xiaojun, Nie; Jianhui, Zhang; Zhengan, Su

    2013-01-01

    Dynamics of soil organic carbon (SOC) are associated with soil erosion, yet there is a shortage of research concerning the relationship between soil erosion, SOC, and especially microbial biomass carbon (MBC). In this paper, we selected two typical slope landscapes including gentle and steep slopes from the Sichuan Basin, China, and used the 137Cs technique to determine the effects of water erosion and tillage erosion on the dynamics of SOC and MBC. Soil samples for the determination of 137Cs...

  18. [Comparison of Monitoring Methods of Organic Carbon and Element Carbon in Atmospheric Fine Particles].

    Science.gov (United States)

    Pang, Bo; Ji, Dong-sheng; Liu, Zi-rui; Zhu, Bin; Wang, Yue-si

    2016-04-15

    Accurate measurement of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particulate is an important scientific basis for studying the formation and source apportionment of carbonaceous aerosol. The selection of different analysis programs will lead to difference in the OC and EC concentrations, and further result in the misjudgment of the results. The OC and EC concentrations observed using three temperature protocols including RT-Quartz ( R) , NIOSH 5040 (N) and Fast-TC (F) were compared and analyzed in combination with the degree of air pollution in Beijing. The results showed that there was no significant difference in the TC (TC = OC + EC), OC and EC concentrations observed using R, N and F protocols and certain deviation was found among the TC (TC = OC + EC) , OC and EC concentrations. For TC, the results observed using R protocol were 5% lower than those using N protocol; hut 1% higher than those using F protocol. For OC, the results obtained using R were 9% lower than those using N protocol and 1% higher than those using F protocol. For EC, the results obtained using R were 20% higher than those using N protocol and 11% lower than those using F protocol. The variation coefficients for TC, OC and EC obtained based on R protocol were less than the other two temperature protocols under different air quality degrees. The slopes of regression curves of TC, OC and EC between on-line analysis using R protocol and off-line analysis were 1.21,1. 14 and 1.35, respectively. The correlation coefficients of TC, OC and EC were 0.99, 0.99 and 0.98, respectively. In contrast with the Black carbon ( BC) concentrations monitored by multi-angle absorption spectrophotometer (MAAP), the EC concentrations measured by on-line OC/EC analyzer using R protocol were obviously lower. When the BC concentrations were less than or equal to 8 gg*m3, the EC/BC ratio was 0.39. While the EC/BC ratio was 0.88, when the BC concentrations were greater than 8 ggm3. The variation

  19. [Comparison of Monitoring Methods of Organic Carbon and Element Carbon in Atmospheric Fine Particles].

    Science.gov (United States)

    Pang, Bo; Ji, Dong-sheng; Liu, Zi-rui; Zhu, Bin; Wang, Yue-si

    2016-04-15

    Accurate measurement of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particulate is an important scientific basis for studying the formation and source apportionment of carbonaceous aerosol. The selection of different analysis programs will lead to difference in the OC and EC concentrations, and further result in the misjudgment of the results. The OC and EC concentrations observed using three temperature protocols including RT-Quartz ( R) , NIOSH 5040 (N) and Fast-TC (F) were compared and analyzed in combination with the degree of air pollution in Beijing. The results showed that there was no significant difference in the TC (TC = OC + EC), OC and EC concentrations observed using R, N and F protocols and certain deviation was found among the TC (TC = OC + EC) , OC and EC concentrations. For TC, the results observed using R protocol were 5% lower than those using N protocol; hut 1% higher than those using F protocol. For OC, the results obtained using R were 9% lower than those using N protocol and 1% higher than those using F protocol. For EC, the results obtained using R were 20% higher than those using N protocol and 11% lower than those using F protocol. The variation coefficients for TC, OC and EC obtained based on R protocol were less than the other two temperature protocols under different air quality degrees. The slopes of regression curves of TC, OC and EC between on-line analysis using R protocol and off-line analysis were 1.21,1. 14 and 1.35, respectively. The correlation coefficients of TC, OC and EC were 0.99, 0.99 and 0.98, respectively. In contrast with the Black carbon ( BC) concentrations monitored by multi-angle absorption spectrophotometer (MAAP), the EC concentrations measured by on-line OC/EC analyzer using R protocol were obviously lower. When the BC concentrations were less than or equal to 8 gg*m3, the EC/BC ratio was 0.39. While the EC/BC ratio was 0.88, when the BC concentrations were greater than 8 ggm3. The variation

  20. Spark Plasma Sintering of Load-Bearing Iron-Carbon Nanotube-Tricalcium Phosphate CerMets for Orthopaedic Applications

    Science.gov (United States)

    Montufar, Edgar B.; Horynová, Miroslava; Casas-Luna, Mariano; Diaz-de-la-Torre, Sebastián; Celko, Ladislav; Klakurková, Lenka; Spotz, Zdenek; Diéguez-Trejo, Guillermo; Fohlerová, Zdenka; Dvorak, Karel; Zikmund, Tomáš; Kaiser, Jozef

    2016-04-01

    Recently, ceramic-metallic composite materials (CerMets) have been investigated for orthopaedic applications with promising results. This first generation of bio-CerMets combine the bioactivity of hydroxyapatite with the mechanical stability of titanium to fabricate bioactive, tough and biomechanically more biocompatible osteosynthetic devices. Nonetheless, these first CerMets are not biodegradable materials and a second surgery is required to remove the implant after bone healing. The present work aims to develop the next generation bio-CerMets, which are potential biodegradable materials. The process to produce the new biodegradable CerMet consisted of mixing powder of soluble and osteoconductive alpha tricalcium phosphate with biocompatible and biodegradable iron with consolidation through spark plasma sintering (SPS). The microstructure, composition and mechanical strength of the new CerMet were studied by metallography, x-ray diffraction and diametral tensile strength tests, respectively. The results show that SPS produces CerMet with higher mechanical performance (120 MPa) than the ceramic component alone (29 MPa) and similar mechanical strength to the pure metallic component (129 MPa). Nonetheless, although a short sintering time (10 min) was used, partial transformation of the alpha tricalcium phosphate into its allotropic and slightly less soluble beta phase was observed. Cell adhesion tests show that osteoblasts are able to attach to the CerMet surface, presenting spread morphology regardless of the component of the material with which they are in contact. However, the degradation process restricted to the small volume of the cell culture well quickly reduces the osteoblast viability.

  1. Organic carbon sedimentation rates in Asian mangrove coastal ecosystems estimated by {sup 210}PB chronology

    Energy Technology Data Exchange (ETDEWEB)

    Tateda, Y.; Wattayakorn, G.; Nhan, D.D.; Kasuya, Y. [Abiko Research Laboratory CRIEPI, Biology Dept., Abiko, Chiba (Japan)

    2004-07-01

    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{sup 3} years scale organic carbon accumulation rates in mangrove coastal ecosystems, {sup 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 {sup 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 {sup 210}Pb chronology that is offset in case of 10{sup 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 {sup 210}Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand with {sup 7}Be analyses to make sure the negligible effect of above turbation effects on organic carbon accumulation. We finally concluded that {sup 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 {sup 210}Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were 0.067 4.0 t-C ha{sup -1} y{sup -1}. (author)

  2. Organic Carbon Isotope Geochemistry of the Neoproterozoic Doushantuo Formation, South China

    Institute of Scientific and Technical Information of China (English)

    GUO Qingjun; LIU Congqiang; Harald STRAUSS; Tatiana GOLDBERG; ZHU Maoyan; PI Daohui; WANG Jian

    2006-01-01

    The Neoproterozoic Doushantuo Formation on the Yangtze Platform, South China,documents a sedimentary succession with different sedimentary facies from carbonate platform to slope and to deep sea basin, and hosts one of the world-class phosphorite deposits. In these strata,exquisitely preserved fossils have been discovered: the Weng'an biota. This study presents carbon isotope geochemistry which is associated paired carbonate and organic matter from the Weng'an section of a carbonate platform (shelf of the Yangtze Platform, Guizhou Province) from the Songtao section and Nanming section of a transition belt (slope of the Yangtze Platform, Guizhou Province) and from the Yanwutan section (basin area of the Yangtze Platform, Hunan Province). Environmental variations and bio-events on the Yangtze Platform during the Late Neoproterozoic and their causal relationship are discussed. Negative carbon isotope values for carbonate and organic carbon (mean δ13Corg = -35.0%) from the uppermost Nantuo Formation are followed by an overall increase in δ13C up-section. Carbon isotope values vary between -9.9% and 3.6% for carbonate and between -35.6% and -21.5% for organic carbon, respectively. Heavier δ13Ccarb values suggest an increase in organic carbon burial, possibly related to increasing productivity (such as the Weng'an biota). The δ13C values of the sediments from the Doushantuo Formation decreased from the platform via the slope to basin,reflecting a reduced environment with minor dissolved inorganic carbon possibly due to a lower primary productivity. It is deduced that the classical upwelling process, the stratification structure and the hydrothermal eruption are principally important mechanisms to interpret the carbon isotopic compositions of the sediments from the Doushantuo Formation.

  3. 有机结合态磷肥对土壤微生物及磷酸酶的影响%Effect of Organic Combined Phosphatic Fertilizers on Soil Microbes and Phosphatase

    Institute of Scientific and Technical Information of China (English)

    王斐; 李菊梅; 戴建军; 马义兵

    2013-01-01

    The results from soil culture and pot culture experiments show that when compared with inorganic phosphatic fertilizers,organic combined phosphatic fertilizers can greatly increase the quantity of soil microbes and the content of soil phosphatase ; the original organic combined phosphatic product is mixed with ground phosphate rock to become organic combined phosphatic fertilizers,which give the best results of increasing the soil microbe quantuity,23 times higher than that of inorganic phosphatic fertilizers,and also the soil phosphatase content,6 times higher than that of inorganic phosphatic fertilizers; next to the results of original organic combined product mixed with slow-release nitrogenous fertilizers,but not much different from the former.Organic combined phosphatic fertilizers have the effect of lowering the soil pH value,good for calcareous soil with a high pH value,and for red earth with a low pH value it is better to choose the compounds of ground phosphate rock mixed with organic combined phosphatic fertilizers,to give good results.%土壤培养和盆栽试验结果表明:与无机磷肥相比,有机结合态磷肥能够大幅提高土壤微生物数量和土壤磷酸酶含量;有机结合态磷原产物与磷矿粉配合的有机结合态磷肥对提高土壤微生物量的效果最好,比无机磷肥提高23倍,对提高土壤磷酸酶含量的效果也最好,比无机磷肥提高约6倍;有机结合态磷原产物与缓释氮配合的效果次之,但与前者差异幅度不大.有机结合态磷肥具有降低土壤pH的效果,对pH较高的石灰性土壤效果良好,在pH低的红壤上应选用磷矿粉与有机结合态磷原产物复合的肥料效果较好.

  4. Organic carbon accumulation capability of two typical tidal wetland soils in Chongming Dongtan, China

    Institute of Scientific and Technical Information of China (English)

    Shiping Zhang; Lei Wang; Jiajun Hu; Wenquan Zhang; Xiaohua Fu; Yiquan Le; Fangming Jin

    2011-01-01

    We measured organic carbon input and content of soil in two wetland areas of Chongming Dongtan (Yangtze River Estuary) to evaluate variability in organic carbon accumulation capability in different wetland soils. Observed differences were investigated based on the microbial activity and environmental factors of the soil at the two sites. Results showed that the organic carbon content of wetland soil vegetated with Phragmites australis (site A) was markedly lower than that with P. australis and Spartina alternifiora (site B). Sites differences were due to higher microbial activity at site A, which led to higher soil respiration intensity and greater carbon outputs.This indicated that the capability of organic carbon accumulation of the site B soils was greater than at site A. In addition, petroleum pollution and soil salinity were different in the two wetland soils. After bio-remediation, the soil petroleum pollution at site B was reduced to a similar level of site A. However, the culturable microbial biomass and enzyme activity in the remediated soils were also lower than at site A. These results indicated that greater petroleum pollution at site B did not markedly inhibit soil microbial activity.Therefore, differences in vegetation type and soil salinity were the primary factors responsible for the variation in microbial activity,organic carbon output and organic carbon accumulation capability between site A and site B.

  5. Biospheric and petrogenic organic carbon flux along southeast Alaska

    Science.gov (United States)

    Cui, Xingqian; Bianchi, Thomas S.; Jaeger, John M.; Smith, Richard W.

    2016-10-01

    Holocene fjords store ca. 11-12% of the total organic carbon (OC) buried in marine sediments with fjords along southeast (SE) Alaska possibly storing half of this OC (Smith et al., 2015). However, the respective burial of biospheric (OCbio) and petrogenic OC (OCpetro) remains poorly constrained, particularly across glaciated versus non-glaciated systems. Here, we use surface sediment samples to quantify the sources and burial of sedimentary OC along SE Alaska fjord-coastal systems, and conduct a latitudinal comparison across a suite of fjords and river-coastal systems with distinctive OC sources. Our results for SE Alaska show that surface sediments in northern fjords (north of Icy Strait) with headwater glaciers are dominated by OCpetro, in contrast to marine and terrestrially-derived fresh OC in non-glaciated southern fjords. Along the continental shelf of the Gulf of Alaska, terrestrial OC is exported from rivers. Using end-member mixing models, we determine that glaciated fjords have significantly higher burial rates of OCpetro (∼ 1.1 ×103 gOC m-2yr-1) than non-glaciated fjords and other coastal systems, making SE Alaska potentially the largest sink of OCpetro in North America. In contrast, non-glaciated fjords in SE Alaska are effective in burying marine OC (OCbio-mari) (13-82 g OC m-2yr-1). Globally, OC in fjord sediments are comprised of a mixture of OCpetro and fresh OCbio, in contrast to the pre-aged OC from floodplain river-coastal systems. We find that there may be a general latitudinal trend in the role of fjords in processing OC, where high-latitude temperate glacial fjords (e.g., Yakutat Bay, SE Alaska) rebury OCpetro and non-glacial mid-latitude fjords (e.g., Doubtful Sound, Fiordland) sequester CO2 from phytoplankton and/or temperate forests. Overall, we propose that fjords are effective in sequestering OCbio and re-burying OCpetro. Based on our study, we hypothesize that climate change will have a semi-predictable impact on fjords' OC cycling in

  6. Hierarchically-organized, well-dispersed hydroxyapatite-coated magnetic carbon with combined organics and inorganics removal properties

    OpenAIRE

    Yang, Huihui; Liu, Qiang; Masse, Sylvie; Zhang, Hao; Li, Laifeng; ,; Coradin, Thibaud

    2015-01-01

    Novel hierarchically-organized magnetic microspheres have been successfully developed that consist of an aqueous hollow core, a magnetic porous Fe3O4-carbon layer and a well-define hydroxyapatite (HAp) shell. The hollow magnetic carbon microspheres were prepared by ultrasonic spray pyrolysis and coated with HAp using a biomimetic approach. The resulting powders exhibit micro- and meso-porosity. The removal capacity of the composite spheres towards an antibiotic (ampicilin), a rare-earth ion (...

  7. 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 oxy

  8. 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

  9. Mycorrhizal mediation of soil organic carbon decomposition under elevated atmospheric carbon dioxide

    Science.gov (United States)

    Significant effort in global change research has recently been directed towards assessing the potential of soil as a carbon sink under future atmospheric carbon dioxide scenarios. Attention has focused on the impact of elevated carbon dioxide on plant interactions with mycorrhizae, a symbiotic soil...

  10. Arterial Blood Carbonic Acid Inversely Determines Lactic and Organic Acids

    OpenAIRE

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    Objective: To establish that arterial blood carbonic acid varies inversely with lactic acid in accordance with bicarbonate exchanging for lactate across cell membranes through the anion exchange mechanism to maintain the Gibbs-Donnan equilibrium.

  11. The coupling of glycolysis and the Rubisco-based pathway through the non-oxidative pentose phosphate pathway to achieve low carbon dioxide emission fermentation.

    Science.gov (United States)

    Li, Ya-Han; Ou-Yang, Fan-Yu; Yang, Cheng-Han; Li, Si-Yu

    2015-01-01

    In this study, Rubisco-based engineered Escherichia coli, containing two heterologous enzymes of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoribulokinase (PrkA), has been shown to be capable of the in situ recycling of carbon dioxide (CO2) during glycolysis. Two alternative approaches have been proposed to further enhance the carbon flow from glycolysis to a Rubisco-based pathway through the non-oxidative pentose phosphate pathway (NOPPP). The first is achieved by elevating the expression of transketolase I (TktA) and the second by blocking the native oxidation-decarboxylation reaction of E. coli by deleting the zwf gene from the chromosome (designated as JB/pTA and MZB, respectively). Decreases in the CO2 yield and the CO2 evolution per unit mole of ethanol production by at least 81% and 40% are observed. It is demonstrated in this study that the production of one mole of ethanol using E. coli strain MZB, the upper limit of CO2 emission is 0.052mol.

  12. Interannual stability of organic to inorganic carbon production on a coral atoll

    Science.gov (United States)

    Kwiatkowski, Lester; Albright, Rebecca; Hosfelt, Jessica; Nebuchina, Yana; Ninokawa, Aaron; Rivlin, Tanya; Sesboüé, Marine; Wolfe, Kennedy; Caldeira, Ken

    2016-04-01

    Ocean acidification has the potential to adversely affect marine calcifying organisms, with substantial ocean ecosystem impacts projected over the 21st century. Characterizing the in situ sensitivity of calcifying ecosystems to natural variability in carbonate chemistry may improve our understanding of the long-term impacts of ocean acidification. We explore the potential for intensive temporal sampling to isolate the influence of carbonate chemistry on community calcification rates of a coral reef and compare the ratio of organic to inorganic carbon production to previous studies at the same location. Even with intensive temporal sampling, community calcification displays only a weak dependence on carbonate chemistry variability. However, across three years of sampling, the ratio of organic to inorganic carbon production is highly consistent. Although further work is required to quantify the spatial variability associated with such ratios, this suggests that these measurements have the potential to indicate the response of coral reefs to ongoing disturbance, ocean acidification, and climate change.

  13. Effects of Low-Molecular-Weight Organic Acids on the Dissolution of Hydroxyapatite Nanoparticles in Batch and Column Experiments: A Perspective from Phosphate Oxygen Isotope Fractionation

    Science.gov (United States)

    Wang, D.; Jaisi, D. P.; Jin, Y.

    2015-12-01

    Hydroxyapatite nanoparticles (HANPs) are increasingly being advocated as an efficient and environment-friendly "green" phosphorus nanofertilizer attributed to their nanoscale dimension, large reactive surface area, and low leaching potential. However, knowledge of how naturally occurring low-molecular-weight organic acids (LMWOAs) that are secreted by plant roots mediate the dissolution of HANPs (releasing PO43- ion for plant growth) is nonexistent. Here three most commonly encountered LMWOAs (acetic acid, oxalic acid, and citric acid) at environmentally relevant concentration (1 mM) were evaluated for their effects on HANPs' dissolution in static batch and dynamic column systems. Particularly, phosphate oxygen isotope fractionation of HANPs during dissolution was examined to disentangle mechanisms controlling the evolution of O-isotopic composition of dissolved PO43- ion. Our results reveal that in batch experiments the dissolution of HANPs was fast but the overall dissolution efficiency of HANPs was limited (≤30%). In contrast, ~100% HANPs were dissolved in columns where LMWOAs were continuously injected. The limited dissolution of HANPs in static batch systems was due primarily to pH buffer effect (pH increased sharply when LMWOA was added in HANPs suspension), whereas in dynamic column systems the HANPs were continuously dissolved by low pH LMWOAs and leached away. Regardless of LMWOA type and experimental system, the isotopically light phosphate (P16O4) was preferentially released during dissolution and the O-isotopic composition of dissolved PO43- ion increased gradually with increasing dissolution due to equilibrium isotope effect between dissolved PO43- ion and HANPs. However, the overall magnitude of O-isotopic fractionation of dissolved PO43- ion was less in batch than in column systems, due to less mass transfer between dissolved PO43- ions and HANPs in batch relative to column experiments. Our findings provide new insights into bioavailability

  14. Estimating organic micro-pollutant removal potential of activated carbons using UV absorption and carbon characteristics.

    Science.gov (United States)

    Zietzschmann, Frederik; Altmann, Johannes; Ruhl, Aki Sebastian; Dünnbier, Uwe; Dommisch, Ingvild; Sperlich, Alexander; Meinel, Felix; Jekel, Martin

    2014-06-01

    Eight commercially available powdered activated carbons (PAC) were examined regarding organic micro-pollutant (OMP) removal efficiencies in wastewater treatment plant (WWTP) effluent. PAC characteristic numbers such as B.E.T. surface, iodine number and nitrobenzene number were checked for their potential to predict the OMP removal of the PAC products. Furthermore, the PAC-induced removal of UV254 nm absorption (UVA254) in WWTP effluent was determined and also correlated with OMP removal. None of the PAC characteristic numbers can satisfactorily describe OMP removal and accordingly, these characteristics have little informative value on the reduction of OMP concentrations in WWTP effluent. In contrast, UVA254 removal and OMP removal correlate well for carbamazepine, diclofenac, and several iodinated x-ray contrast media. Also, UVA254 removal can roughly describe the average OMP removal of all measured OMP, and can accordingly predict PAC performance in OMP removal. We therefore suggest UVA254 as a handy indicator for the approximation of OMP removal in practical applications where direct OMP concentration quantification is not always available. In continuous operation of large-scale plants, this approach allows for the efficient adjustment of PAC dosing to UVA254, in order to ensure reliable OMP removal whilst minimizing PAC consumption. PMID:24651017

  15. Metal-organic gel templated synthesis of magnetic porous carbon for highly efficient removal of organic dyes.

    Science.gov (United States)

    Wang, Luhuan; Ke, Fei; Zhu, Junfa

    2016-03-21

    Magnetic porous carbon composites are promising materials in various applications, such as adsorbents, supercapacitors and catalyst supports, due to their high surface area, thermal and chemical stability, and easy separation. However, despite the increasing number of reports of magnetic porous carbon composites, the preparation of these materials with environmentally friendly procedures still remains a great challenge. Herein, we report a facile method to prepare a magnetic porous carbon composite with high surface area from a Fe-based metal-organic gel (MOG) template, an extended structure of a metal-organic framework (MOF). The obtained magnetic porous carbon composite was applied to remove organic dyes from an aqueous solution by selecting methyl orange (MO) as a model molecule. It exhibits excellent adsorption capacity (182.82 mg g(-1)), fast adsorption kinetics (8.13 × 10(-3) g mg(-1) min(-1)), and a perfect magnetic separation performance for the MO removal. This study demonstrates a new way to achieve clean synthesis of magnetic porous carbon materials, and opens a new door for the application of MOGs in organic dye removal.

  16. Evaluating soil organic carbon and nutrient storage in a sustainable forest chestnut management context

    OpenAIRE

    Patrício, Maria do Sameiro; Nunes, Luís; Pereira, Ermelinda

    2013-01-01

    Forests fix carbon dioxide from the atmosphere and sequester it in biomass, timber products and soils (stock effect). Soil organic carbon (SOC) is the major stock of the terrestrial biosphere with great importance for the balance of carbon at the global scale. Nowadays, a reliable estimate of the stored C, in the mineral soil pool of forest ecosystems, is of great importance in helping Governments to make decisions in carrying out the Kyoto Protocol. In this study the quantification of C and ...

  17. An exploratory spatial analysis of soil organic carbon distribution in Canadian eco-regions

    OpenAIRE

    Tan, S.-Y.; Li, J.

    2014-01-01

    As the largest carbon reservoir in ecosystems, soil accounts for more than twice as much carbon storage as that of vegetation biomass or the atmosphere. This paper examines spatial patterns of soil organic carbon (SOC) in Canadian forest areas at an eco-region scale of analysis. The goal is to explore the relationship of SOC levels with various climatological variables, including temperature and precipitation. The first Canadian forest soil database published in 1997 by the Canada Fo...

  18. 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.

  19. POLY(TRIMETHYLENE CARBONATE) AND BIPHASIC CALCIUM PHOSPHATE COMPOSITES FOR ORBITAL FLOOR RECONSTRUCTION : A FEASIBILITY STUDY IN SHEEP

    NARCIS (Netherlands)

    van Leeuwen, A. C.; Yuan, H.; Passanisi, G.; van der Meer, J. W.; de Bruijn, J. D.; van Kooten, T. G.; Grijpma, D. W.; Bos, R. R. M.

    2014-01-01

    In the treatment of orbital floor fractures, bone is ideally regenerated. The materials currently used for orbital floor reconstruction do not lead to the regeneration of bone. Our objective was to render polymeric materials based on poly(trimethylene carbonate) (PTMC) osteoinductive, and to evaluat

  20. Organic Carbon Geochemistry in the North-western Black Sea Danube River System

    Science.gov (United States)

    Galimov, E. M.; Kodina, L. A.; Zhiltsova, L. I.; Tokarev, V. G.; Vlasova, L. N.; Bogacheva, M. P.; Korobeinik, G. S.; Vaisman, T. I.

    2002-03-01

    The isotopic and chemical composition of organic matter from sediments collected on the north-western shelf of the Black Sea and the Danube River are discussed. The δ 13C distribution pattern in organic carbon from surface sediments (0-1 cm) of the western part of the Black Sea has been established. It reveals a rather complicated picture, reflecting the superposition of several factors: local marine primary productivity, terrestrial input to the Danube River discharge and possible contribution from anaerobic microbial activity. The analysis of organic carbon by a pyrolysis-chromatography technique showed that the H/O indices of organic matter from marine sediments are in correlation with δ 13C values. This is an indication of the mixed origin of the organic carbon in the littoral sediments. However, samples from the zone where H 2S conditions prevail deviate from the correlation line of δ 13C vs H/O indices. We believe that this is due to the contribution of the biomass of chemosynthetic bacteria in the sediments. Thus, we argue that in the Danube-Black Sea system several consecutive zones are distinguished. River discharge delivers organic carbon with δ 13C values from -28 to -26 (PSU is used). Mixing of the land-derived material with autochtonous marine primary production gives δ 13C values of about -26 to -23 for the organic carbon in coastal sediments. On the shelf area, beyond significant influence of both terrestrial and sulphide regime factors, plankton material dominates as a source of organic carbon in sediments. In the hydrogen sulphide zone, chemosynthetic bacteria produce additional amounts of organic matter with hydrogen to oxygen indices similar to those of plankton, but with different isotopic composition, which results in the appearance of relatively isotopically light organic carbon in the deep-sea sediments.

  1. VIIRSN Level-3 Standard Mapped Image, Particulate Organic Carbon, Monthly, 4km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes Particulate Organic Carbon data from ther NPP-Suomi spacecraft. Measurements are gathered by VIIRS instrument carried aboard the...

  2. VIIRSN Level-3 Standard Mapped Image, Particulate Organic Carbon, 8-Day, 4km

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes Particulate Organic Carbon data from the NPP-Suomi Spacecraft Measurements are gathered by the VIIRS instrument carried aboard the...

  3. Organic carbon in the sediments of the lower reaches of Periar River

    Digital Repository Service at National Institute of Oceanography (India)

    Devi, K.S.; Venugopal, P.; Sankaranarayanan, V.N.

    Sediments are indicators of the quality of water overlying them and hence, useful in the assessment of environmental pollution. Temporal and spatial variations in sediment characteristics and organic carbon content from 9 stations in the lower...

  4. 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...

  5. 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.

  6. 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

    a core-shell formation of COP material grafted to the outer layers of activated carbon. This general method brings features of both COPs and porous carbons together for target-specific environmental remediation applications, which was corroborated with successful adsorption tests for organic dyes...

  7. EPIC modeling of soil organic carbon sequestration in croplands of Iowa

    Science.gov (United States)

    Agricultural lands can mitigate detrimental effects of greenhouse gases because soils can be managed to reduce carbon dioxide emissions and sequester carbon in soil organic matter. Simulation models are useful tools for studying the long-term impacts of crop and soil management practices on soil org...

  8. Impacts of soil redistribution on the transport and fate of organic carbon in loess soils

    NARCIS (Netherlands)

    X. Wang

    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

  9. Stock characteristics of soil organic carbon pools under three subtropical forests in South China

    Science.gov (United States)

    Zhang, X. Y.; Guan, D. S.; Xiao, M. Z.

    2016-08-01

    Vegetation biomass and soil organic carbon (SOC) pools for the three representative forest types, i.e. conifer forest (CF), mixed conifer and broad-leaf forest (CBF), evergreen broad-leaf forest (EBF) in South China were investigated. We found that SOC stock of the three chief forest ranged from 55.54 to 151.16 MgC·ha-1, and it increased with increasing vegetation biomass under the same type forest within 100cm depth. The organic carbon contents at an equivalent level of forest maturity tended to be in the following decreasing order: EBF > CBF > CF, various active organic carbon (AOC) fractions in the 0-20cm topsoil layer tended to be in the following decreasing order: light fraction carbon (LFC) ≈ particulate organic carbon (POC) > easily oxidisable carbon (EOC) > microbial biomass carbon (MBC) > water-soluble carbon (WSC). At an equivalent level of forest maturity, there was a trend that each of these five AOC fractions increased from CF to CBF to the EBF.

  10. 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

  11. Impacts of management practices on soil organic carbon in degraded alpine meadows on the Tibetan Plateau

    OpenAIRE

    X. F. Chang; Wang, S.P.; X. X. ZHU; Cui, S. J.; Luo, C. Y.; Zhang, Z. H.; A. Wilkes

    2014-01-01

    Grassland soil organic carbon (SOC) is sensitive to anthropogenic activities. Increased anthropogenic disturbance related to overgrazing has led to widespread alpine grassland degradation on the Tibetan Plateau. The degraded grasslands are considered to have great potential for carbon sequestration after adoption of improved management practices. Here, we calibrated and employed the Century model to investigate the effects of overgrazing and improved managem...

  12. Surface modification of hollow magnetic Fe3O4@NH2-MIL-101(Fe) derived from metal-organic frameworks for enhanced selective removal of phosphates from aqueous solution

    Science.gov (United States)

    Li, Yan; Xie, Qiying; Hu, Qian; Li, Chengping; Huang, Zhangjie; Yang, Xiangjun; Guo, Hong

    2016-01-01

    Hollow magnetic Fe3O4@NH2-MIL-101(Fe) derived from metal-organic frameworks are fabricated through a general facile strategy. The synthetic parameters are regulated to control the shape of the as-prepared samples. The concentration of phosphates decreased sharply from the initial 0.60 to 0.045 mg.L−1 with the exposure time in 50 minutes. The correlation between the most significant parameters such as contact time, adsorbent dose, pH, as well as adsorption capacities was optimized, and the effects of these parameters on the removal efficiency of phosphates were investigated. Surface functionalization of magnetic hollow materials is a well-designed way to bridge the gap between high adsorption activity, excellent separation and recovery of phosphates from the water treatment system. Therefore, it exhibits a remarkable selective removal of phosphates from aqueous solution. PMID:27470443

  13. Surface modification of hollow magnetic Fe3O4@NH2-MIL-101(Fe) derived from metal-organic frameworks for enhanced selective removal of phosphates from aqueous solution.

    Science.gov (United States)

    Li, Yan; Xie, Qiying; Hu, Qian; Li, Chengping; Huang, Zhangjie; Yang, Xiangjun; Guo, Hong

    2016-01-01

    Hollow magnetic Fe3O4@NH2-MIL-101(Fe) derived from metal-organic frameworks are fabricated through a general facile strategy. The synthetic parameters are regulated to control the shape of the as-prepared samples. The concentration of phosphates decreased sharply from the initial 0.60 to 0.045 mg.L(-1) with the exposure time in 50 minutes. The correlation between the most significant parameters such as contact time, adsorbent dose, pH, as well as adsorption capacities was optimized, and the effects of these parameters on the removal efficiency of phosphates were investigated. Surface functionalization of magnetic hollow materials is a well-designed way to bridge the gap between high adsorption activity, excellent separation and recovery of phosphates from the water treatment system. Therefore, it exhibits a remarkable selective removal of phosphates from aqueous solution. PMID:27470443

  14. Molecular, radioactive and stable carbon isotope characterization of estuarine particulate organic matter

    OpenAIRE

    Megens, L.; van der Plicht, J.; De Leeuw, JW; Leeuw, Jan W. de; Mook, W.G.

    1998-01-01

    Organic matter in sediments and suspended matter is a complex mixture of constituents with different histories, sources and stabilities. To study these components in a suspended matter sample from the Ems-Dollard Estuary, we used combined molecular analysis with pyrolysis/gas chromatography/mass spectrometry and stable and radioactive carbon isotope analyses of the bulk and separated chemical fractions. Carbohydrates and proteins, ca. 50% of the total organic carbon (TOC), are much younger th...

  15. Organic carbon source and burial during the past one hundred years in Jiaozhou Bay, North China

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; YUAN Huamao; LI Ning; SONG Jinming

    2008-01-01

    Organic carbon (OC), total nitrogen (TN), and 210Pb in core sediment were measured to quantify the burial of organic carbon and the relative importance of allochthonous and autochthonous contributions during the past one hundred years in Jiaozhou Bay, North China. The core sediment was dated using 210Pb chronology, which is the most promising method for estimation of sedimentation rate on a time scale of 100-150 years. The variation of the burial flux of organic carbon in the past one hundred years can be divided into the following three stages: (1) relatively steady before 1980s; (2) increasing rapidly from the 1980s to a peak in the 1990s, and (3) decreasing from the 1990s to the present. The change is consistent with the amount of solid waste and sewage emptied into the bay. The OC:TN ratio was used to evaluate the source of organic carbon in the Jiaozhou Bay sediment. In the inner bay and bay mouth, the organic carbon was the main contributor from terrestrial sources, whereas only about half of organic carbon was contributed from terrestrial source in the outer bay. In the inner bay, the terrestrial source of organic carbon showed a steady change with an increase in the range of 69%-77% before 1990 to 93% in 2000, and then decreased from 2000 because of the decrease in the terrestrial input. In the bay mouth, the percentage of organic carbon from land reached the highest value with 94% in 1994. In the outer bay, the sediment source maintained steady for the past one hundred years.

  16. The percentage of living bacterial cells related to organic carbon release from senescent oceanic phytoplankton

    OpenAIRE

    S. Lasternas; S. Agustí

    2014-01-01

    Bacteria recycle vast amounts of organic carbon, playing key biogeochemical and ecological roles in the ocean. Bacterioplankton dynamics are expected to be dependent on phytoplankton primary production, but there is a high diversity of processes (e.g., sloppy feeding, cell exudation, viral lysis) involved in the transfer of primary production to dissolved organic carbon available to bacteria. Here, we show the percentage of living heterotrophic bacterioplankton in the subtro...

  17. Small organic amine assisted synthesis of an extra-large pore containing open-framework zinc-cobalt phosphate templated by a chain-type polyamine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An open-framework zinc-cobalt phosphate CoZnPO4-V with 16-ring extra-large-pore channels has been obtained in the presence of chain-type polyamines as the structure directing agent (SDA). Its large single crystal suited for structure refinement has been prepared with the assistance of small organic amines. Single-crystal X-ray diffraction analysis has shown that CoZnPO4-V is a novel metal phosphate. It crystallizes in monoclinic space group P21/c (No. 14), with a = 31.936(3) , b = 8.3775(7) , c = 15.7874(13) , α = γ = 90°, β = 97.0530(10)°, V = 4191.8(6) 3, and Z = 4 with R1 = 0.0455,wR2 = 0.0869. Its three-dimensional framework can be considered as stacking from two-dimensional nets and one-dimensional units as linkers. Between the stacking nets and linkers are located extra-large channels with 16-ring apertures.

  18. Small organic amine assisted synthesis of an extra-large pore containing open-framework zinc-cobalt phosphate templated by a chain-type polyamine

    Institute of Scientific and Technical Information of China (English)

    LI DaiPing; SONG HaiBin; WANG HongGen; LI Niu; GUAN NaiJia; XIANG ShouHe

    2009-01-01

    An open-framework zinc-cobalt phosphate CoZnPO4-V with 16-ring extra-large-pore channels has been obtained in the presence of chain-type polyamines as the structure directing agent (SDA).Its large single crystal suited for structure refinement has been prepared with the assistance of small organic amines.Single-crystal X-ray diffraction analysis has shown that CoZnPO4-V is a novel metal phosphate.It crystallizes in monoclinic space group P21/c (No.14),with a=31.936(3)(A),b = 8.3775(7)(A),c=15.7874(13) (A),a= y=90°,#=97.0530(10)°,V=4191.8(6)(A)3,and Z=4 with R1 =0.0455,wR2=0.0869.Its three-dimensional framework can be considered as stacking from two-dimensional nets and onedimensional units as linkers.Between the stacking nets and linkers are located extra-large channels with 16-ring apertures.

  19. Soil Organic Carbon, Black Carbon, and Enzyme Activity Under Long-Term Fertilization

    Institute of Scientific and Technical Information of China (English)

    SHAO Xing-hua; ZHENG Jian-wei

    2014-01-01

    The present study aims to understand the effects of long-term fertilization on soil organic carbon (SOC), black carbon (BC), enzyme activity, and the relationships among these parameters. Paddy ifeld was continuously fertilized over 30 yr with nine different fertilizer treatments including N, P, K, NP, NK, NPK, 2NPK (two-fold NPK), NPK+manure (NPKM), and CK (no fertilization), N, 90 kg urea-N ha-1 yr-1; P, 45 kg triple superphosphate-P2O5 ha-1 yr-1; K, 75 kg potassium chloride-K2O ha-1 yr-1;and pig manure, 22 500 kg ha-1 yr-1. Soil samples were collected and determined for SOC, BC content, and enzyme activity. The results showed that the SOC in the NPKM treatment was signiifcantly higher than those in the K, P, and CK treatments. The lowest SOC content was found in the CK treatment. SOC content was similar in the N, NP, NK, NPK, 2NPK, and NPKM treatments. There was no signiifcant difference in BC content among different treatments. The BC-to-SOC ratios (BC/SOC) ranged from 0.50 to 0.63, suggesting that BC might originate from the same source. Regarding enzyme activity, NPK treatment had higher urease activity than NPKM treatment. The urease activity of NPKM treatment was signiifcantly higher than that of 2NPK, NP, N, P, K, CK, and NPKM treatment which produced higher activities of acid phosphatase, catalase, and invertase than all other treatments. Our results indicated that long-term fertilization did not signiifcantly affect BC content. Concurrent application of manure and mineral fertilizers increased SOC content and signiifcantly enhanced soil enzyme activities. Correlation analysis showed that catalase activity was signiifcantly associated with invertase activity, but SOC, BC, and enzyme activity levels were not signiifcantly correlated with one another. No signiifcant correlations were observed between BC and soil enzymes. It is unknown whether soil enzymes play a role in the decomposition of BC.

  20. 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.

  1. Symmetric organization of self-assembled carbon nitride

    International Nuclear Information System (INIS)

    A scheme for creating 'flower-like' nanostructures of carbon nitride is described that involves the self-assembly of nanocrystals following laser ablation of a solid graphite target immersed in aqueous ammonia solution. The primary nanocrystals possess rod-like symmetry, and then self-assemble upon drying to form nanoleaf or nanopetal shaped structures. Samples were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), x-ray photoelectron microscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The analyses confirmed their composition to be consistent with that of crystalline β-phase carbon nitride. The morphologies of the carbon nitride nanostructures depended strongly on the synthesis conditions and upon the conditions under which the aqueous suspension of ablated particles were dried

  2. Nanosized Carbon Dots from Organic Matter and Biomass

    Institute of Scientific and Technical Information of China (English)

    LI Yuanyuan; CHEN Tong; MA Yulong

    2016-01-01

    Carbon nanoparticles (C-dots) were prepared by relfuxing the combustion soots of candles and corn stalk in nitric acid. The synthesized C-dots were characterized. The results showed a sharp increase in oxygen content and a sharp decrease in carbon content after oxidation. The C-dots had -OH and -CO2H groups introduced which made them hydrophilic. However, their difference was also obvious. The C-dots from candle soot had a 10-45 nm broad particle size distribution, and those from corn stalk soot had a 6-18 nm relatively small and narrow size distribution. The C-dots were mainly ofsp2 andsp3 carbon structure different from the C-dots of diamond-like structure from candle soot. Interestingly, two kinds of C-dots all exhibited unique photoluminescent properties. The obtained C-dots have potential applications in a broad range of areas.

  3. The carbon copy of human activities : how long-term land use explains spatial variability of soil organic carbon stocks at multiple scales

    NARCIS (Netherlands)

    Schulp, C.J.E.

    2009-01-01

    Invloed van landgebruik, landgebruik-geschiedenis en management op de koolstofvoorraad in de bodem in Nederland.The carbon copy of human activities - how long-term land use explains spatial variability of soil organic carbon stocks at multiple scales.

  4. 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.

  5. Soil labile organic carbon and carbon-cycle enzyme activities under different thinning intensities in Chinese fir plantations

    NARCIS (Netherlands)

    Chen, Xinli; Chen, Han Y.H.; Chen, Xin; Wang, Jing; Chen, Bin; Wang, Dong; Guan, Qingwei

    2016-01-01

    Thinning is a silvicultural tool that is used to facilitate the growth of timber plantations worldwide. Plantations are important CO2 sinks, but the mechanism by which thinning affects the quantity and stability of soil organic carbon (SOC) is poorly understood. In this study, we exami

  6. Absorption features of chromophoric dissolved organic matter (CDOM) and tracing implication for dissolved organic carbon (DOC) in Changjiang Estuary, China

    OpenAIRE

    X. Y. Zhang; 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...

  7. 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.

  8. 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.

  9. Dual carbon isotope characterization of total organic carbon in wintertime carbonaceous aerosols from northern India

    Science.gov (United States)

    Bikkina, Srinivas; Andersson, August; Sarin, M. M.; Sheesley, R. J.; Kirillova, E.; Rengarajan, R.; Sudheer, A. K.; Ram, K.; Gustafsson, Örjan

    2016-05-01

    Large-scale emissions of carbonaceous aerosols (CA) from South Asia impact both regional climate and air quality, yet their sources are not well constrained. Here we use source-diagnostic stable and radiocarbon isotopes (δ13C and Δ14C) to characterize CA sources at a semiurban site (Hisar: 29.2°N, 75.2°E) in the NW Indo-Gangetic Plain (IGP) and a remote high-altitude location in the Himalayan foothills (Manora Peak: 29.4°N, 79.5°E, 1950 m above sea level) in northern India during winter. The Δ14C of total aerosol organic carbon (TOC) varied from -178‰ to -63‰ at Hisar and from -198‰ to -1‰ at Manora Peak. The absence of significant differences in the 14C-based fraction biomass of TOC between Hisar (0.81 ± 0.03) and Manora Peak (0.82 ± 0.07) reveals that biomass burning/biogenic emissions (BBEs) are the dominant sources of CA at both sites. Combining this information with δ13C, other chemical tracers (K+/OC and SO42-/EC) and air mass back trajectory analyses indicate similar source regions in the IGP (e.g., Punjab and Haryana). These results highlight that CA from BBEs in the IGP are not only confined to the atmospheric boundary layer but also extend to higher elevations of the troposphere, where the synoptic-scale circulations could substantially influence their abundances both to the Himalayas and over the downwind oceanic regions such as the Indian Ocean. Given the vast emissions of CA from postharvest crop residue combustion practices in the IGP during early Northeast Monsoon, this information is important for both improved process and model understanding of climate and health effects, as well as in guiding policy decision aiming at reducing emissions.

  10. Open tube combustion method of organic samples for stable carbon isotope analysis.

    Science.gov (United States)

    Velivetskaya, Tatiana A; Ignatyev, Alexander V; Reize, Marina V; Kiyashko, Serguei I

    2007-01-01

    A simple and effective method for the conversion of organic carbon into carbon dioxide for analysis of stable carbon isotopes (delta(13)C) in samples of various organic substances, soils, sedimentary rocks, oils and volatile organic liquids is presented. The conversion of organic carbon of the samples is carried out in a quartz reactor connected to a vacuum line for CO(2) freezing and purification. A solid organic sample mixed with CuO is placed at the reactor bottom and the reactor is subsequently filled with granular CuO. One end of the CuO column is preheated to 850 degrees C while the other end of the column in contact with the sample is kept at ambient temperature. Heating of the sample (850 degrees C) and the remainder of the column is then performed. The preheated part of the column provides efficient conversion of carbon into CO(2). The reactor for the conversion of volatile liquid organic compounds is filled with granular CuO. The column of CuO is heated to 850 degrees C. Samples of volatile liquids are introduced into the reactor through a septum using a microsyringe. Complete conversion takes 10 min for solid samples and 3 min for volatile liquids. The precision of the delta(13)C analysis for solid and volatile liquid organic substances is +/-0.1 per thousand and +/-0.04 per thousand, respectively.

  11. Characterization of Dissolved Organic Carbon in Deep Groundwater from the Witwatersrand Basin

    Science.gov (United States)

    Pullin, M. J.; Hendrickson, S.; Simon, P.; Sherwood Lollar, B.; Wilkie, K.; Onstott, T. C.; Washton, N.; Clewett, C.

    2013-12-01

    This work describes the isolation, fractionation, and chemical analysis of dissolved organic carbon (DOC) in deep groundwater in the Witwatersrand Basin, South Africa. The groundwater was accessed through mining boreholes in gold and diamond mine shafts. Filtered water samples were collected and preserved for later analysis. In some cases, the organic carbon was also collected on DAX-8 and XAD-4 adsorption resins in situ and then transported to the surface for removal, clean-up, and lyophilization. Solid state C-13 NMR analysis of that organic carbon was conducted. Organic compounds were also isolated from the water using solid phase extraction cartridges for later analysis by GC-MS. Absorbance, fluorescence, and HPLC analyses was were used to analyze the DOC in the filtered water samples. C-14 and C-13 isotopic analysis of the organic carbon was also conducted. Identifiable components of the DOC include both organic acids and amino acids. However, initial results indicate that the majority of the subsurface DOC is a complex heterogeneous mixture with an average molecular weight of approximately 1000 Da, although this DOC is less complex than that found in soils or surface water. Finally, we will discuss possible sources of the organic carbon and its biogeochemical cycling in the subsurface.

  12. 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.

  13. A molecular organic carbon isotope record of Miocene climate changes

    NARCIS (Netherlands)

    Schoell, M.; Schouten, S.; Sinninghe Damsté, J.S.; Leeuw, J.W. de; Summons, R.E.

    1994-01-01

    The difference in carbon-13 (13C) contents of hopane and sterane biomarkers in the Monterey formation (Naples Beach, California) parallels the Miocene inorganic record of the change in 18O (δ18O), reflecting the Miocene evolution from a well-mixed to a highly stratified photic zone (upper 100 meters

  14. Reexposure and advection of C-14-depleted organic carbon from old deposits at the upper continental slope

    OpenAIRE

    Tesi, Tommaso; Goñi, Miguel A.; Langone, Leonardo; Puig, Pere; Canals, Miquel; Nittrouer, Charles A.; Durrieu De Madron, Xavier; Calafat, Antoni; Palanques, Albert; Heussner, Serge; Davies, Maureen H.; Drexler, Tina M.; Fabres, Joan; Miserocchi, Stefano

    2010-01-01

    Outcrops of old strata at the shelf edge resulting from erosive gravity-driven flows have been globally described on continental margins. The reexposure of old strata allows for the reintroduction of aged organic carbon (OC), sequestered in marine sediments for thousands of years, into the modern carbon cycle. This pool of reworked material represents an additional source of C-14-depleted organic carbon supplied to the ocean, in parallel with the weathering of fossil organic carbon delivered ...

  15. Complete Transmetalation in a Metal-Organic Framework by Metal Ion Metathesis in a Single Crystal for Selective Sensing of Phosphate Ions in Aqueous Media.

    Science.gov (United States)

    Asha, K S; Bhattacharjee, Rameswar; Mandal, Sukhendu

    2016-09-12

    A complete transmetalation has been achieved on a barium metal-organic framework (MOF), leading to the isolation of a new Tb-MOF in a single-crystal (SC) to single-crystal (SC) fashion. It leads to the transformation of an anionic framework with cations in the pore to one that is neutral. The mechanistic studies proposed a core-shell metal exchange through dissociation of metal-ligand bonds. This Tb-MOF exhibits enhanced photoluminescence and acts as a selective sensor for phosphate anion in aqueous medium. Thus, this work not only provides a method to functionalize a MOF that can have potential application in sensing but also elucidates the formation mechanism of the resulting MOF.

  16. 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.

  17. Carbon dioxide capturing technologies: a review focusing on metal organic framework materials (MOFs).

    Science.gov (United States)

    Sabouni, Rana; Kazemian, Hossein; Rohani, Sohrab

    2014-04-01

    In this study, a relevant literature has been reviewed focusing on the carbon dioxide capture technologies in general, such as amine-based absorption as conventional carbon dioxide capturing technology, aqueous ammonia-based absorption, membranes, and adsorption material (e.g., zeolites, and activated carbons). In more details, metal organic frameworks (MOFs) as new emerging technologies for carbon dioxide adsorption are discussed. The MOFs section is intended to provide a comprehensive overview of MOFs including material characteristics and synthesis, structural features, CO2 adsorption capacity, heat of adsorption and selectivity of CO2. PMID:24338107

  18. Soil organic carbon storage and soil CO2 flux in the alpine meadow ecosystem

    Institute of Scientific and Technical Information of China (English)

    TAO Zhen; SHEN ChengDe; GAO QuanZhou; SUN YanMin; YI WeiXi; LI YingNian

    2007-01-01

    High-resolution sampling, measurements of organic carbon contents and 14C signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau, and application of 14C tracing technology were conducted in an attempt to investigate the turnover times of soil organic carbon and the soil-CO2 flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12(104 kg C hm-2 to 30.75(104 kg C hm-2 in the alpine meadow ecosystems, with an average of 26.86(104 kg C hm-2. Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO2 flux ranges from 103.24 g C m-2 a-1 to 254.93 gC m-2 a-1, with an average of 191.23 g C m-2 a-1. The CO2 efflux produced from microbial decomposition of organic matter varies from 73.3 g C m-2 a-1 to 181 g C m-2 a-1. More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%-81.23% of total CO2 emitted from organic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming, the storage, volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed, which needs further research.

  19. Soil organic carbon storage and soil CO2 flux in the alpine meadow ecosystem

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    High-resolution sampling,measurements of organic carbon contents and 14C signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau,and application of 14C tracing technology were conducted in an attempt to investigate the turnover times of soil organic car-bon and the soil-CO2 flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12×104 kg C hm-2 to 30.75×104 kg C hm-2 in the alpine meadow eco-systems,with an average of 26.86×104 kg C hm-2. Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO2 flux ranges from 103.24 g C m-2 a-1 to 254.93 gC m-2 a-1,with an average of 191.23 g C m-2 a-1. The CO2 efflux produced from microbial decomposition of organic matter varies from 73.3 g C m-2 a-1 to 181 g C m-2 a-1. More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%―81.23% of total CO2 emitted from or-ganic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming,the storage,volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed,which needs further research.

  20. A Simple Approach to Estimate Soil Organic Carbon and Soil CO2 Emission

    Directory of Open Access Journals (Sweden)

    Farhat Abbas

    2013-01-01

    Full Text Available SOC (Soil Organic Carbon and soil CO 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 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 2 emission over short- and long-term basis for global climate change assessment studies.

  1. A metabolic trade-off between phosphate and glucose utilization in Escherichia coli.

    Science.gov (United States)

    Behrends, Volker; Maharjan, Ram P; Ryall, Ben; Feng, Lu; Liu, Bin; Wang, Lei; Bundy, Jacob G; Ferenci, Thomas

    2014-11-01

    Getting the most out of available nutrients is a key challenge that all organisms face. Little is known about how they optimize and balance the simultaneous utilization of multiple elemental resources. We investigated the effects of long-term phosphate limitation on carbon metabolism of the model organism Escherichia coli using chemostat cultures. We profiled metabolic changes in the growth medium over time and found evidence for an increase in fermentative metabolism despite the aerobic conditions. Using full-genome sequencing and competition experiments, we found that fitness under phosphate-limiting conditions was reproducibly increased by a mutation preventing flux through succinate in the tricarboxylic acid cycle. In contrast, these mutations reduced competitive ability under carbon limitation, and thus reveal a conflicting metabolic benefit in the role of the TCA cycle in environments limited by inorganic phosphate and glucose.

  2. Co-precipitation of dissolved organic matter by calcium carbonate in Pyramid Lake, Nevada

    Science.gov (United States)

    Leenheer, Jerry A.; Reddy, Michael M.

    2008-01-01

    Our previous research has demonstrated that dissolved organic matter (DOM) influences calcium carbonate mineral formation in surface and ground water. To better understand DOM mediation of carbonate precipitation and DOM co-precipitation and/or incorporation with carbonate minerals, we characterized the content and speciation of DOM in carbonate minerals and in the lake water of Pyramid Lake, Nevada, USA. A 400-gram block of precipitated calcium carbonate from the Pyramid Lake shore was dissolved in 8 liters of 10% acetic acid. Particulate matter not dissolved by acetic acid was removed by centrifugation. DOM from the carbonate rock was fractionated into nine portions using evaporation, dialysis, resin adsorption, and selective precipitations to remove acetic acid and inorganic constituents. The calcium carbonate rock contained 0.23% DOM by weight. This DOM was enriched in polycarboxylic proteinaceous acids and hydroxy-acids in comparison with the present lake water. DOM in lake water was composed of aliphatic, alicyclic polycarboxylic acids. These compound classes were found in previous studies to inhibit calcium carbonate precipitation. DOM fractions from the carbonate rock were 14C-age dated at about 3,100 to 3,500 years before present. The mechanism of DOM co-precipitation and/or physical incorporation in the calcium carbonate is believed to be due to formation of insoluble calcium complexes with polycarboxylic proteinaceous acids and hydroxy-acids that have moderately large stability constants at the alkaline pH of the lake. DOM co-precipitation with calcium carbonate and incorporation in precipitated carbonate minerals removes proteinaceous DOM, but nearly equivalent concentrations of neutral and acidic forms of organic nitrogen in DOM remain in solution. Calcium carbonate precipitation during lime softening pretreatment of drinking water may have practical applications for removal of proteinaceous disinfection by-product precursors.

  3. Determining the Carbon-Carbon Distance in an Organic Molecule with a Ruler

    Science.gov (United States)

    Simoni, Jose A.; Tubino, Matthieu; Ricchi, Reinaldo Alberto, Jr.

    2004-01-01

    The procedure to estimate the carbon-carbon bond distance in the naphthalene molecule is described. The procedure is easily performed and can be done either at home or in the classroom, with the restriction that the mass of the naphthalene must be determined using an analytical or a precise balance.

  4. Fluvial organic carbon flux from an eroding peatland catchment, southern Pennines, UK

    Directory of Open Access Journals (Sweden)

    R. R. Pawson

    2007-04-01

    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, 40.8 t organic carbon (OC is exported from the catchment, which represents an areal value of 107 gC m−2 a−1. POC was the most significant form of organic carbon export, accounting for ~82% 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. 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.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    B. Tiemeyer

    2014-02-01

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

  8. Quantification of functional soil organic carbon pools in a chronosequence of land abandonment in southern Spain.

    Science.gov (United States)

    Trigalet, Sylvain; Gabarrón-Galeote, Miguel A.; Van Oost, Kristof; van Wesemael, Bas

    2015-04-01

    Land abandonment is the dominant land use change in the Mediterranean, and determines the soil organic carbon (SOC) as the vegetation recovers during secondary succession. The rate of SOC recovery is influenced by environmental factors such as precipitation, soil properties or other local factors. Using aerial photographs taken in 1956, 1977, 1984, 1998, 2001 and 2009, a chronosequence of crop land abandonment was designed and topsoil samples were taken at each stage of recovery in a region North of Málaga. As SOC is a mixture of functional pools, it is important to isolate organic carbon with distinct functional properties to better understand the overall dynamic over decades. Using fractionation scheme introduced by Zimmermann et al. (2007), five fractions were isolated based on particle size, density and resistance: particulate organic matter (POM), dissolved organic carbon (DOC), SOC linked to silt and clay (s & c), SOC attached to sand particles or occluded in aggregates (S+A) and a chemically resistant fraction obtained by NaOCl oxidation (rSOC). Although there were no significant changes in particle-size distribution between the recovery stages (except for the croplands), there was a significant increase of S+A fraction over time (16 to 38%) at the expense of the s & c fraction (84 to 58%), indicating aggregation processes. Carbon concentrations within fractions S+A or rSOC did not change over time. Rather, carbon associated with silt and clay particles (s &c) was significantly affected after a few decades of abandonment. It increased from 5.7 gC.kg-1 in croplands to 10.3 gC.kg-1 in semi-natural plots. The chronosequence showed that carbon can be stored in more stable fractions. Taking into account active carbon (DOC + POM) and intermediate carbon (s & c, S+A) as indicators for carbon dynamics, we showed that the proportion of active carbon increased from 11% to 34% within the chronosequence. On the other hand, the proportion of slow cycling carbon

  9. Linking CDOM spectral absorption to dissolved organic carbon concentrations and loadings in boreal estuaries

    DEFF Research Database (Denmark)

    Asmala, Eero; Stedmon, Colin A.; Thomas, David N.

    2012-01-01

    The quantity of chromophoric dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in three Finnish estuaries (Karjaanjoki, Kyrönjoki and Kiiminkijoki) was investigated, with respect to predicting DOC concentrations and loadings from spectral CDOM absorption measurements. Altogether 87...

  10. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

  11. Kinetics of continuous biodegradation of pesticide organic wastewater by activated carbon-activated sludge

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Organic triazophos wastewater was continuously treated with Rhodopseudomonas capsulatus and activated carbon and activated sludge system(PACT-AS) in a plug bioreactor. A kinetic model of PACT-AS wastewater treatment system was established to provide an useful basis for further simulate scale-up treatment of toxic organic wastewater.

  12. Adopting soil organic carbon management practices in soils of varying quality

    NARCIS (Netherlands)

    Merante, Paolo; Dibari, Camilla; Ferrise, Roberto; Sánchez, Berta; Iglesias, Ana; Lesschen, Jan Peter; Kuikman, Peter; Yeluripati, Jagadeesh; Smith, Pete; Bindi, Marco

    2017-01-01

    Soil organic carbon (SOC) content can greatly affect soil quality by determining and maintaining important soil physical conditions, properties and soil functions. Management practices that maintain or enhance SOC affect soil quality and may favour the capacity of soils to sequester further organ

  13. Partitioning Carbon Dioxide Emission and Assessing Dissolved Organic Carbon Leaching of a Drained Peatland Cultivated with Pineapple at Saratok, Malaysia

    Directory of Open Access Journals (Sweden)

    Liza Nuriati Lim Kim Choo

    2014-01-01

    Full Text Available Pineapples (Ananas comosus (L. Merr. cultivation on drained peats could affect the release of carbon dioxide (CO2 into the atmosphere and also the leaching of dissolved organic carbon (DOC. Carbon dioxide emission needs to be partitioned before deciding on whether cultivated peat is net sink or net source of carbon. Partitioning of CO2 emission into root respiration, microbial respiration, and oxidative peat decomposition was achieved using a lysimeter experiment with three treatments: peat soil cultivated with pineapple, bare peat soil, and bare peat soil fumigated with chloroform. Drainage water leached from cultivated peat and bare peat soil was also analyzed for DOC. On a yearly basis, CO2 emissions were higher under bare peat (218.8 t CO2 ha/yr than under bare peat treated with chloroform (205 t CO2 ha/yr, and they were the lowest (179.6 t CO2 ha/yr under cultivated peat. Decreasing CO2 emissions under pineapple were attributed to the positive effects of photosynthesis and soil autotrophic activities. An average 235.7 mg/L loss of DOC under bare peat suggests rapid decline of peat organic carbon through heterotrophic respiration and peat decomposition. Soil CO2 emission depended on moderate temperature fluctuations, but it was not affected by soil moisture.

  14. Partitioning carbon dioxide emission and assessing dissolved organic carbon leaching of a drained peatland cultivated with pineapple at Saratok, Malaysia.

    Science.gov (United States)

    Lim Kim Choo, Liza Nuriati; Ahmed, Osumanu Haruna

    2014-01-01

    Pineapples (Ananas comosus (L.) Merr.) cultivation on drained peats could affect the release of carbon dioxide (CO2) into the atmosphere and also the leaching of dissolved organic carbon (DOC). Carbon dioxide emission needs to be partitioned before deciding on whether cultivated peat is net sink or net source of carbon. Partitioning of CO2 emission into root respiration, microbial respiration, and oxidative peat decomposition was achieved using a lysimeter experiment with three treatments: peat soil cultivated with pineapple, bare peat soil, and bare peat soil fumigated with chloroform. Drainage water leached from cultivated peat and bare peat soil was also analyzed for DOC. On a yearly basis, CO2 emissions were higher under bare peat (218.8 t CO2 ha/yr) than under bare peat treated with chloroform (205 t CO2 ha/yr), and they were the lowest (179.6 t CO2 ha/yr) under cultivated peat. Decreasing CO2 emissions under pineapple were attributed to the positive effects of photosynthesis and soil autotrophic activities. An average 235.7 mg/L loss of DOC under bare peat suggests rapid decline of peat organic carbon through heterotrophic respiration and peat decomposition. Soil CO2 emission depended on moderate temperature fluctuations, but it was not affected by soil moisture. PMID:25215335

  15. Assessing Impacts of 20 yr Old Miscanthus on Soil Organic Carbon Quality

    Science.gov (United States)

    Hu, Yaxian; Schäfer, Gerhard; Kuhn, Nikolaus

    2015-04-01

    The use of biomass as a renewable energy source has become increasingly popular in Upper Rhine Region to meet the demand for renewable energy. Miscanthus is one of the most favorite biofuel crops, due to its long life and large yields, as well as low energy and fertilizer inputs. However, current research on Miscanthus is mostly focused on the techniques and economics to produce biofuel or the impacts of side products such as ash and sulfur emissions to human health. Research on the potential impacts of Miscanthus onto soil quality, especially carbon quality after long-term adoption, is very limited. Some positive benefits, such as sequestrating organic carbon, have been repeatedly reported in previous research. Yet the quality of newly sequestrated organic carbon and its potential impacts onto global carbon cycling remain unclear. To fully account for the risks and benefits of Miscanthus, it is required to investigate the quality as well as the potential CO2 emissions of soil organic carbon on Miscanthus fields. As a part of the Interreg Project to assess the environmental impacts of biomass production in the Upper Rhine Region, this study aims to evaluate the carbon quality and the potential CO2 emissions after long-term Miscanthus adoption. Soils were sampled at 0-10, 10-40, 40-70, and 70-100 cm depths on three Miscanthus fields with up t